Hand Fingertip Amputations, Dupuytren's, Vascular 01-22, 24 Flashcards

Question

A 40-year-old man sustained traumatic amputation of all fingers of the dominant hand 3 months ago. Tripod pinch reconstruction is planned with a double second toe transfer. Which of the following arteries is most likely to be the dominant blood supply to the second toe transfer in this patient? A) First dorsal metatarsal artery B) First plantar metatarsal artery C) Lateral plantar artery D) Medial plantar artery E) Third plantar metatarsal artery

Answer 1

The correct response is Option A. The first dorsal metatarsal artery (FDMA) is the dominant blood supply (to the great toe and second toe) in approximately 70% of cases. The first plantar metatarsal artery (FPMA) is the dominant blood supply in 20% of cases. The FDMA and the FPMA have a similar vessel caliber in the remaining 10% of cases. The dominant vascular pattern can be evaluated by careful retrograde dissection that begins at the dorsal aspect of the first web space. The junction of the lateral digital artery of the great toe and the medial digital artery of the second toe can be identified just above the intermetatarsal ligament. Proximal dissection continues dorsally and plantarly to evaluate the FDMA and FPMA. If the FDMA is the larger caliber vessel or of similar caliber to the FPMA, then the toe transfer can be based on the FDMA. Proximal dissection of the FDMA to obtain length is relatively straightforward. In the setting of a plantar dominance, dissection of the FPMA is carried out proximally, which can be more challenging. Plantar proximal dissection is typically limited to the mid metatarsal level to avoid additional morbidity. If additional length is required on the FPMA pedicle, a vein graft can be used. It is important to note that in bilateral second toe transfers, the dominant vascular pattern can be asymmetric in 20% of patients.

Answer 2

The correct response is Option D. Psoriatic arthritis often presents with auto-fusion of the small hand joints and diffuse fusiform swelling of the digits. This psoriatic dactylitis or "sausage digit" is caused by inflammation of periosteum, tendon, and tendon insertions. Nail deformities include pitting, leukonychia, nail crumbling, and onycholysis (separation of nail plate from bed). Nail deformities affect approximately 80% of patients with psoriatic arthritis, and 50% of patients with psoriasis. Nail lichen planus (NLP) is characterized by thinning, longitudinal ridging, and distal splitting of the nail plate. NLP is usually resistant to topical corticosteroid therapy, but successful treatment has been reported with intralesional or systemic administration of corticosteroids. Characteristic skin lesions of arsenic poisoning include hyperkeratosis and Mees’ lines. Mees’ lines are prominent transverse white lines in fingernails or toe-nails due to arsenic deposition in keratin-rich tissues. Subungual melanoma has distinct cutaneous nail manifestations such as brown or black streaks in the nail without any known injury, streaks on the nails that increase in size, or a "bruise" on the nail that will not heal or move up as the fingernail grows. One of the key indications of subungual melanoma is known as "Hutchinson's sign." This is when a person has a streak that extends from the tip of the nail down to the nail bed and into the eponychium. Nail disorders in HIV-infected patients include clubbing, splitting of the nails, or discoloration (black or brown lines going either vertically or horizontally).

Answer 3

The correct response is Option B. The medication that is used to reverse the effects of epinephrine is phentolamine, which is an alpha-adrenergic receptor blocker. The wide-awake Hand Surgery is well described by Donald Lalonde and utilizes the effects of local anesthesia to perform a wide variety of hand-surgical procedures without general anesthesia. An alpha-adrenergic receptor activator, such as epinephrine, could increase vasoconstriction and worsen the scenario, as could a beta-adrenergic receptor blocker. Sodium channel blockers and potassium channel activators are not indicated for reversal of epinephrine effect.

Answer 4

The correct response is Option E. The reasonable maximum time frame for replantation of an appropriately cooled and stored digit (referred to as cold ischemia time) is 24 hours. However, the warm ischemia time for digital replantation is 12 hours. These times are further reduced when replanting more proximally amputated limbs, such as an arm or leg, because of the presence of ischemia-sensitive muscle. The recommended maximum cold ischemia time to replantation in these major replants is 12 hours; the warm ischemia time is 6 hours. Despite these recommended time frames, successful replantations performed many hours after the amputations have been reported. In 1986, May et al. reported a successful digit replantation after 39 hours of cold ischemia, the seventh of a seven-finger replant. Then, in 1988, Wei et al. reported successful digital replantations after 84, 86, and 94 hours of cold ischemia. Whenever there is more muscle mass in the replanted limb, ischemia time becomes more critical. In these clinical scenarios, immediate shunting should be considered especially when the ischemia time is nearing the time frames described above. The other options are incorrect because they are within the ideal maximum time frame.

Answer 5

The correct response is Option C. The most appropriate indication to perform a replantation is the level of the amputation. Replantation of an amputation distal to the flexor digitorum superficialis is attempted because the function of the digit is improved with additional length to a normal proximal interphalangeal joint. An amputation in a child is an indication for replantation (adult age is not). Hand dominance is not a major variable in the determination of whether or not to perform a replantation. Replantation of single digits (including the index finger) at the proximal phalanx or proximal interphalangeal joint in adults often is not performed because the limited motion of the digit can inhibit overall hand function. An exception is any level amputation of the thumb, which is a major indication for replantation because the thumb provides 40 to 50% of hand function. Smoking status is not a major variable for the consideration of replantation.

Answer 6

The correct response is Option B. Case reports have been documented of ischemia and subsequent tissue necrosis following elective hand surgery using lidocaine with epinephrine. The vasoconstrictive effect of epinephrine is a result of its stimulation of alpha-adrenergic receptors. Phentolamine, an alpha-adrenergic antagonist, has been used effectively to reverse the vasoconstrictive effect of epinephrine. When used in the hand, phentolamine rescue is carried out by injecting 1 to 2 mg of phentolamine in 1 to 5 mL of saline into the area where epinephrine was used. The reversal of vasoconstriction should result within 1 hour. Digital ischemia following accidental EpiPen injection into the hand has also been reported. The use of topical terbutaline infiltration has been attempted in such cases. In one case series, terbutaline infiltration was found to be effective in reversing vasoconstriction in some, but not all cases. The conclusion reached in the study was that terbutaline should be considered as an alternative when phentolamine is not available. The use of topical nitroglycerin and warm water immersion has not been proven to be an effective method to reverse the alpha-adrenergic effect of epinephrine. If prolonged ischemia is a concern following the use of lidocaine with epinephrine, further management, such as phentolamine rescue, should be considered given that complications such as distal digital amputation have occurred.

Answer 7

The correct response is Option C. Contracture of the first web space may be secondary to cutaneous scarring, skin deficiency, fibrosis of the fascia and thenar muscles, or joint contractures. Mild contractures may be isolated to the skin; however, deeper structures are most likely involved as the contracture becomes more severe. It is important to understand the mechanism of injury, length of time the contracture has been present, and any prior treatments. Reconstruction of the first web space involves complete contracture release and resurfacing with adequate vascularized tissue. The dissection should be carried out palmarly and dorsally with release of the palmar fascia and adductor aponeurosis as needed. Intrinsic muscle and joint contractures should be addressed at this time, and a trapeziectomy may be needed to restore carpometacarpal (CMC) motion. This patient has a severe contracture that likely involves multiple structures given her history of deep lacerations and bony injury. This requires resurfacing with thin, pliable vascularized tissue. In this setting, the posterior interosseous artery (PIA) flap is the best choice. This flap is outside the zone of injury and provides an adequate amount of vascularized tissue for resurfacing of the web space. The PIA runs between the extensor carpi ulnaris and extensor digit quinti and forms an anastomosis with the anterior interosseous artery 2cm proximal to the distal radioulnar joint. Skin grafting alone, either split-thickness or full-thickness, should be avoided because of the inherent tendency for secondary contracture. Skin grafts may be combined with local flaps such as a 4-flap or 5-flap z-plasty in mild to moderate contractures. Tissue flaps from the dorsum of the hand such as the first dorsal metacarpal artery fasciocutaneous flap or dorsal hand transposition flap may be good options in some patients with small- to moderate-sized skin deficits. However, this patient sustained trauma to the dorsal hand with dorsal skin lacerations. This makes a random-pattern transposition flap unreliable. The defect in question is also too large to be completely resurfaced with a first dorsal metacarpal artery (FDMA) flap. The flexor carpi ulnaris flap is useful for elbow coverage as a turn-over flap but will not reach the hand.

Answer 8

The correct response is Option B. Patients presenting with Raynaud syndrome fall into two classic categories: primary (traditionally referred to as Raynaud disease) and secondary (Raynaud phenomenon, associated with an underlying condition, most commonly involving an autoimmune process). In this woman presenting without an underlying etiology for her vasospastic symptoms, primary treatment should be directed at managing the vasospasm. Although a plethora of interventions have been tried, recent reviews show the calcium-channel blockers, such as nifedipine, to be the optimal first-line intervention. Temperature biofeedback has shown variable effect in multiple small trials, and, consequently, it is not recommended as a primary intervention for vasospasm. Topical nitrates can assist with vasodilation in the digits, making them an occasional adjunct treatment for symptoms not completely managed by calcium channel blockers. In isolation, topical nitrates have been ineffective for managing Raynaud syndrome. Multiple small trials have demonstrated successful relief of pain and digital ulcers in a mixed group of both primary and secondary Raynaud syndrome with injection of botulinum toxin around the digital vessels in the palm. The cost and risk of temporary paralysis to intrinsic muscles, however, renders this a second-line treatment for refractory pain or nonhealing ulcers. Treatment of digital vasospasm is still considered an "off-label" use of botulinum toxin and may not be covered by insurance. Surgical sympathectomy, either proximally through a thoracoscopic approach or peri-arterially in the wrist and hand, represents the most aggressive treatment and would typically be reserved for patients with nonhealing wounds or chronic ischemic changes. These procedures are gradually being supplanted by injection of botulinum toxin type A.

Answer 9

The correct response is Option A. A reverse homodigital island flap is shown. It is a distally based flap that is useful in the repair of fingertip injuries. Arterial inflow is based upon the contralateral digital artery in the crossing ladder vessels of the palmar digital arch that lie just dorsal to the volar plate at each joint. The flap requires sacrifice of the ipsilateral digital artery and care must be taken to preserve the digital nerve during elevation of the skin paddle. Typically, the donor site is grafted.

Answer 10

The correct response is Option D. The patient is presenting with evidence of Volkmann ischemic contracture of his deep volar forearm compartment musculature, specifically flexor digitorum profundus and flexor pollicis longus. Flexor digitorum superficialis could be minimally involved, but the wrist flexors are spared. Mild median nerve involvement with full recovery and sparing of the ulnar nerve would support this diagnosis. The patient has already undergone appropriate physiotherapy. With persistent findings at 4 months, the most appropriate treatment is surgical exploration, debridement of necrotic muscle, with either selective muscle origin slide or tendon lengthening of preserved but contracted muscle. Although continued dynamic physiotherapy could potentially provide further improvement in this patient's muscle tightness, strengthening physiotherapy will not address the problem adequately. Dynamic splinting could complement physiotherapy and be helpful but has likely provided most of its benefit in the 4 months after initial surgery. Intrinsic releases would be indicated in intrinsic muscle contractures; however, this patient has involvement of the extrinsic flexors, not the intrinsic muscles. Finally, flexor tendon transfers would be indicated for more severe cases of Volkmann contractures, where there is no muscle function remaining. This patient's examination suggests adequate muscle function remains.

Answer 11

The correct response is Option E. This patient presents with hypothenar hammer syndrome. The gold standard for establishing the diagnosis is angiography. Aortic arch and upper extremity arteriography is the study of choice. In hypothenar hammer syndrome, the pathognomonic angiographic features can include tortuosity of the ulnar artery with a corkscrew appearance, aneurysm formation, occlusion of the ulnar artery segment overlying the hook of the hamate, occluded digital arteries in the ulnar artery distribution, and demonstration of intraluminal emboli at sites of digital obstruction. Treatment depends largely on the severity of the ischemia. The therapeutic strategy is controversial because there are limited studies on this problem. For most patients with milder or transient/intermittent symptoms, nonsurgical treatment will be sufficient, particularly in the setting of vasospasm with adequate collateral circulation. Conservative nonoperative care may include smoking cessation, avoidance of further trauma (may require change of occupation), padded protective gloves, cold avoidance, calcium channel blockers (nifedipine, diltiazem), antiplatelet agents or anticoagulation, local care of fingers with necrosis, and pentoxifylline to reduce blood viscosity. More severe symptoms (persistent ischemia, soft tissue loss/gangrene, ulnar nerve symptoms) or symptoms refractory to nonoperative management require consideration of surgical intervention. Surgical options in this setting include arterial ligation (assuming an intact radial/palmar arch), resection of thrombosed arterial segment or aneurysm with end-to-end anastomosis, or resection and vascular reconstruction with vein or artery graft. Some argue that best outcomes are seen in those treated with surgical resection and reconstruction. The benefits of surgical treatment include removal of the source of embolism, removal of the painful mass, relief of ulnar nerve compression, and creation of a local periarterial sympathectomy. As this patient has mild and intermittent symptoms without evidence of soft-tissue loss or gangrene or any evidence of ulnar nerve irritation, a trial medical management is indicated. Botulinum toxin type A is indicated for vasospasm secondary to Raynaud syndrome or disease and would not be part of the medical management algorithm.

Answer 12

The correct response is Option C. When caring for patients with mangling hand injuries, it is imperative to consider all aspects of the patient’s history and future goals. This patient would be at risk for cardiac complications if a longer procedure such as a free flap were chosen. The amount of bone loss in the index and middle metacarpals is also problematic and would most likely require multiple procedures. Just placing an external fixation and covering the wound with a local flap is also possible but will require several procedures. Bone grafting while receiving bilaminate neodermis (Integra) and skin grafts is not recommended because of the lack of subcutaneous tissue and poor blood supply. The most expeditious method of covering this patient's wounds in one procedure is finger fillet flaps of the injured digits. Finger fillet flaps can cover a large area for reconstruction as shown.

Answer 13

The correct response is Option C. The thumb is considered to account for at least 40% of hand function. Essential characteristics to provide optimal function of the thumb include mobility, opposition, sensation, stability, strength, and normal shape. Metacarpal distraction can provide a strong, stable, and sensate thumb but is not very aesthetically pleasing as it will be larger than a normal thumb and lack a nail. Osteoplastic reconstruction and flap coverage provides a stable post but no mobility and poor sensation with the same visual concerns. Web space deepening with Z-plasty can provide a very functional stable thumb with more distal amputations but would not provide sufficient length in this patient. Silicone prostheses provide excellent cosmetic digits but are not functional. The most appropriate reconstruction in this patient without a toe transfer would be an index pollicization.

Answer 14

The correct response is Option D. Fat grafting (also called lipofilling) has shown promise as a means to improve outcomes after percutaneous needle aponeurotomy for Dupuytren disease. It is believed to work by several mechanisms: Reducing the density of cell-to-cell myofibroblast contact Inhibiting myofibroblast proliferation via adipose-derived stem cells Acting as an interposed tissue graft Providing passing over the cords to replace native subdermal fat displaced by the nodules and cords A randomized prospective trial by Kan and colleagues showed that aponeurotomy with lipofilling showed equivalent results at one year out from treatment with a much faster recovery compared with limited fasciectomy.

Answer 15

The correct response is Option E. The most appropriate next test is manometry. The patient is exhibiting signs of compartment syndrome after swelling due to fracture under a tight restrictive cast. Signs and symptoms of compartment syndrome include pain with passive stretch, increased pressure on palpation, paresthesia, paralysis, pallor, and pulselessness. Early recognition and treatment are necessary to prevent permanent damage. The pressure within the muscles increases, preventing blood flow to the area and capillary exchange of nutrients. Fasciotomy is recommended if compartment pressure exceeds 30 mmHg, or if the difference between intracompartmental pressure and diastolic blood pressure is less than 30 mmHg. Without treatment, ischemic necrosis to the muscles can result, leading to Volkmann ischemic contracture and causing permanent disability. Scarring and shortening of the muscles can occur, with resultant contracted intrinsic minus appearance of the hand. Compartment pressures can be measured by handheld manometer (Stryker pen), or needle manometer method (Whitesides) with an arterial line setup. Operative fasciotomy is indicated to release the compartment pressures and prevent tissue loss and muscle necrosis in cases of compartment syndrome. Loss of pulse typically occurs later in the spectrum of findings. Angiography would be useful in evaluating vasculature and blood flow. Typically pain with passive stretch does not occur in cases of arterial insufficiency. Duplex ultrasound can evaluate the presence of deep venous thrombosis, which can be a source of pain and swelling. This can occur through compression of the antecubital region, but in this case, the symptomatology would prompt measurement of compartment pressures and urgent fasciotomy. Electromyography can be used to evaluate nerve function but would not be the next appropriate measure. CT scan can provide detailed imaging but would not be indicated in this situation and would delay treatment.

Answer 16

The correct response is Option B. The choice of wrist disarticulation compared with transradial amputation is a controversial one. The primary benefit of the wrist level disarticulation is preservation of the distal radioulnar joint and consequential improvement in forearm rotation. Preservation of the metaphyseal flare of the radius may aid in prosthetic fit; however, the additional length associated with functional units such as myoelectrics may result in a limb length discrepancy. The prominence of the distal radius and ulna may predispose to pressure-related wound issues associated with prosthetic wear. Patients with wrist level disarticulation are more likely to abandon their prosthesis compared with transradial amputees.

Answer 17

The correct response is Option C. Iannuzzi and colleagues have summarized the treatment for acute arterial thrombosis of the hand. Prevention of further damage should be the first line of treatment while completing work-up of the patient. They recommend that heparin and aspirin should be administered to prevent propagation of further arterial occlusion. While the idea of reducing vasospasm in the surrounding vessels is appealing, Iannuzzi's review of the literature is inconclusive of any benefit for tissue salvage outcomes. The article is also useful for comparison of the various imaging modalities for definitive diagnosis and approach to treatment. In their meta-analysis for the Cochrane library, Berridge et al. surveyed the literature and came to the conclusion that distal limb salvage was similar at 30 days, 6 months, and 1 year with either surgical extraction of clot or thrombolysis by direct delivery of the agent to the artery in question. Bleeding and distal embolization were more common after use of thrombolytic agents at 30 days. Robertson et al, also in meta-analysis for the Cochrane library, found some differences favoring tissue plasminogen activator (tPA) in initial vessel patency, but there were no differences in limb salvage outcomes with intra-arterial delivery of tPA or urokinase. In the streptokinase vs tPA studies, there were increased bleeding complications noted with streptokinase.

Answer 18

The correct response is Option E. The indications for surgery in an extravasation injury include full-thickness skin necrosis, chronic ulceration, and persistent pain. Whereas blistering indicates a partial-thickness skin loss, it is alone not an indication for surgery. Erythema, induration, and poor capillary refill (blanching) are signs of extravasation injury but are not indications for an operative intervention.

Answer 19

The correct response is Option D. In this scenario, the physician should rule out compartment syndrome for several reasons: the crush injury, the reperfusion state, and pain unrelieved by pain medications prior to providing more pain relief. Pain that is out of proportion to the expected level or out of proportion to examination findings should alert the clinician to the possibility of compartment syndrome. The only study option provided that would give the clinician the ability to rule out compartment syndrome is the direct measurement of compartment pressures, which is recommended by several authors. Loss of peripheral artery pulses or perfusion to the distal skin would be very late presentations of the ischemic process, at a point where intervention, such as fasciotomy may not be effective. Missing this diagnosis in a patient such as this one, may lead to loss of muscular function (ischemic muscle contracture) even if the limb as a whole is salvaged. The presence of palpable pulses is reassuring evidence for the patency of the bypass graft but does not tell the clinician about the perfusion in the capillary beds of the muscle. Similarly, perfusion of the skin and the digits does not guarantee flow in the muscle that was reperfused.

Answer 20

The correct response is Option E. In patients who sustain digital amputation as a result of an avulsion mechanism, there is often an extensive zone of injury that precludes primary vascular anastomosis. Vein grafts permit vascular anastomosis outside of the zone of injury. Bone shortening can sometimes allow excision of the injured vasculature and primary anastomosis. However, in this case, bone shortening is unlikely to make up for a 2-cm vascular gap. Longer vascular gaps can be addressed with vein grafts. Despite the fact that vein grafts involve an additional anastomosis per vessel compared to primary anastomosis, they have been found to exhibit similar rates of thrombosis and replantation survival. Medicinal leech therapy can help address venous congestion, but is typically considered when venous congestion occurs after attempt at surgical replantation, or if no suitable veins can be found for anastomosis. While postoperative warming and systemic heparin are often used adjunctively in patients undergoing replantation, they have not been demonstrated to increase the likelihood of survival of the replanted part, and would most likely not have as significant an effect as restoring perfusion to the amputated part using vein grafts.

Answer 21

The correct response is Option D. The most efficient sequence to perform the replantation is structure by structure: bone, tendons, arteries, nerves, and then veins. It has been shown that the time to complete the procedure is significantly shorter if the same anatomic structure on each severed digit is fixed before repairing the next structures, as opposed to completing all aspects of the replantation one digit at a time. With respect to the sequence of repair of the severed structures, the general thought is to have a stable construct prior to starting the delicate microscopic repairs. However, the technical sequence used by microsurgeons varies greatly. The only consistent agreement is starting with bony shortening and fixation. The traditional sequence that follows is extensor and flexor tendon repair, and then vessel/nerve repair. However, individual surgeon preference and patient circumstances dictate the usual sequence thereafter. Some surgeons like to start dorsally and complete the extensor tendon, venous, and skin repair first, and then complete the volar structures next. On the volar side, some surgeons repair the tendon first, followed by the artery and nerve, while others fix the artery and nerve first, followed by the tendon. There are those who believe that the nerve is better repaired in a bloodless field, so that should be done first. Others feel that repairing the vein first reduces blood loss and keeps a bloodless field more reliably for better vision. In patients who present with long ischemia time, it may be beneficial to anastomose the artery first, because this provides the advantages of earlier revascularization and allows easier detection of the most functional veins by their spurting backflow. In short, any of these sequences is fine, as long as it follows the bony fixation. The other options are incorrect sequences for the above reasons.

Answer 22

The correct response is Option C. For patients who have patent arterial inflow on imaging, spasm is likely to be responsible for their ischemia. Spasm is most common in those with autoimmune disease. Digital sympathectomy involves stripping the adventitia from the radial, ulnar, and digital arteries in an effort to decrease sympathetic input that is the presumed cause of pathologic vasoconstriction. Vascular occlusion with a satisfactory distal target may require an interposition bypass. Occlusion without a distal target for bypass may require venous arterialization. In the absence of evidence of occlusion, there is no indication for thrombolytic therapy.

Answer 23

The correct response is Option A. The mechanism of injury has the greatest influence on survival of replanted digits. Injuries from sharp devices that leave a clean cut with little or no crush component are the most amenable to replantation. The more the tissue is crushed or avulsed, resulting in greater vessel injury, the less likely the digit will survive. No studies have shown that the use of anticoagulants changes survival rates. Smoking decreases blood flow in digits, but has not been widely studied in replantation. Fingers have no muscle, which is the tissue most susceptible to ischemia, so digits can tolerate long delays as long as they are treated correctly. At least two veins per artery have been shown to help prevent venous congestion.

Answer 24

The correct response is Option A. Ulnar artery aneurysms may cause symptoms because of local mass effect, distal embolization, and/or episodic vasospasm. Ligation of the ulnar artery to exclude the aneurysm from hand circulation can effectively eliminate risk for embolism, but may rob the digits of necessary blood flow if there is not enough collateral circulation from the deep arch or other sources. Measuring the digital-brachial index (DBI) is an effective way to assess whether or not there is sufficient blood flow to the digits. A normal DBI is between 0.75 and 0.97. Values equal to or less than 0.7 indicate inadequate perfusion. Below a DBI of 0.5, tissue loss is inevitable. Following ulnar artery ligation, if the DBI is below 0.7, then reconstruction of the ulnar artery is recommended rather than simple aneurysm excision or ligation. This is typically accomplished with a reversed vein graft or an arterial graft (e.g., from the lateral femoral circumflex system). Anticoagulation alone, or anti-vasospastic drugs, such as botulinum toxin type A or lidocaine, are not sufficient in this clinical situation, where blood flow is limited because of blockage of flow. While sympathectomy could improve circulation in cases of vasospasm, this patient had no history of this, and sympathectomy alone would not be a substitute for arterial reconstruction.

Answer 25

The correct response is Option B. Thumb reconstruction remains a difficult challenge for hand surgeons. Amputations of the skin distally may be covered with palmar advancement flaps; however, this technique is only limited to wounds less than 50% of the palmar surface of the thumb distal to the interphalangeal joint. In order to preserve length and function in more proximal amputations, either a regional or distant flap is required. The toe-to-thumb wraparound flap requires a microvascular anastomosis of digital vessels and nerves, providing excellent sensation and cosmetic results. The toe donor site can be covered with a skin graft in order to preserve length. The volar neurovascular advancement flap would not adequately cover a defect this size. Amputation at the mid-proximal phalanx would result in a very short thumb with loss of function. The radial forearm flap may be utilized to cover the above defect; however, it would lack adequate sensation. Any osteocutaneous radial forearm flap would not be indicated since there is preservation of the bone. Similarly, a second toe-to-thumb transfer would not be indicated since there is preservation of bone in this patient.

Answer 26

The correct response is Option D. Transfer of the index finger to the thumb position on the hand (pollicization) typically transfers the proximal phalanx to the thumb metacarpal, as long as the base of the thumb metacarpal is preserved. Transfer of the middle phalanx or metacarpal of the index would create a neo-thumb that is too short or too large, respectively. Obliterating an intact carpometacarpal joint by transferring the index metacarpal to the trapezium would eliminate palmar and ulnar abduction of the thumb and compromise global hand function.

Answer 27

The correct response is Option B. There are several sensate options for thumb pulp deformities. These include neurovascular island flaps, Moberg flaps, free toe pulp flaps, and the first dorsal metacarpal artery flap (FDMA). Cross finger flaps, skin grafts, and pedicle groin flaps do not have innate innervation. The defect in the question involves the entire pulp of the thumb overlying the distal phalanx and is too large for a Moberg advancement flap. The FDMA flap is supplied by its eponymous artery, which travels in the fascia overlying the index metacarpal and supplies the skin overlying the dorsum of the proximal phalanx. The vessel is accompanied superficially by a branch of the radial nerve that provides neural activation to the skin overlying the proximal phalanx of the index finger. The flap can be transposed to provide sensate coverage of the tip of the thumb, and can provide sufficient size to resurface relatively large defects. Cortical reorientation is the fact that the brain recognizes a stimulus from the flap area as a stimulus from the thumb, and not from the index finger. This process takes some time, but is usually complete after 2 years. Average static two-point discrimination in these flaps utilized for thumb resurfacing is 10 to 11 mm. Use of the FDMA flap for resurfacing of the thumb pulp has been compared to heterodigital island flaps in several studies. Both remain options to be considered, but the ease of elevation, limited dissection, and acceptable donor site morbidity make the FDMA flap a common primary option for thumb tip resurfacing.

Answer 28

The correct response is Option C. Several mechanisms have been proposed to explain the effect of botulinum toxin type A (Botox) to inhibit Raynaud phenomenon in patients with scleroderma. Studies have demonstrated inhibition of Rho/Rho kinase activity, inhibition of substance P secretion and receptor sensitivity, and decreasing the activity of chronically up-regulated C-fiber nociceptors all to occur in models of Raynaud phenomenon that responded to Botox treatment. Fast sodium channels conduct axonal signals AT in gap junctions, but have not been shown to be affected by Botox. Myofibroblasts may be involved in late fibrosis of scleroderma patients but do not exist within the vascular smooth muscle.

Answer 29

The correct response is Option B. The venous flow-through flap was described for small defects of the dorsum of a digit or hand where end-to-end anastomoses of the included veins on the proximal and distal edges of the flap can provide venous outflow for the digit and supply the flap. A defect from the distal, volar surface of the thumb would not have any veins large enough to use. A cross-finger flap is a classical solution to cover the volar aspect of a digit. The other mentioned flaps are also excellent options for volar thumb coverage, except for the thenar flap. The thenar flap is used for distal pulp defects of the fingers in children. The only flap that maintains the normal sensation of the thumb pulp is the Moberg flap, which advances the volar aspect of the thumb on its neurovascular pedicles. The islandized (O'Brien) modification was to make a transverse incision at the base of the thumb and dissect the neurovascular bundles to allow the flap to travel further distally, and then placing a skin graft over the proximal defect.

Answer 30

The correct response is Option B. A body-powered prosthesis uses motion of remaining joints, such as the gleno-humeral and scapulo-thoracic joints, to control an upper extremity prosthesis. Targeted muscle reinnervation (TMR) would not affect function of a body-powered prosthesis. TMR positions amputated nerve stumps well within the remaining muscle and far from the cutaneous closure. Current prosthetics are not yet able to detect sensation and transmit this to the patient. Having nerve stumps near the amputation closure site increases the risk for neuroma pain. TMR has not been shown to decrease denervation atrophy of residual upper extremity muscles. TMR has gained increasing acceptance in the treatment of patients who have undergone or will undergo upper extremity amputation. Resected nerves, such as the median and ulnar nerves, can be coapted to nerve branches to remaining muscles, such as the pectoralis and deltoid. Transcutaneous EMG detectors are positioned over these reinnervation sites to detect nerve signal, which a myoelectric prosthesis can then use to better control distal joints. TMR does not affect the amount of bony length that can be preserved in an amputation.

Answer 31

The correct response is Option C. Fingertip injuries are one of the most common problems encountered in hand surgery. The long finger is the most common finger involved. The patient's age, occupation, and compliance with treatment should be considered when determining treatment. When possible, if the patient has no exposed bone or only a small area of exposed bone, treatment with dressing changes offers excellent results. There is no donor site morbidity, scarring is often minimal, and return of sensation is generally excellent. Patients, however, need to be cautioned that a prolonged period of dressing changes is required, often lasting 3 to 6 weeks. Amputation at the distal interphalangeal joint would result in loss of function of the profundus tendon and grip weakness. Neurovascular island flaps and V-to-Y advancement flaps offer excellent closure options when digital length needs to be preserved and there is significant exposure of bone. However, with these flaps there is a donor defect and decreased sensation. Care must be taken when using a cross-finger flap or thenar flap in older patients to avoid contractures and stiffness of the digits.

Answer 32

The correct response is Option E. Injection of botulinum toxin around the digital vessels in the palm has been shown to decrease pain associated with vasospastic disorders like Raynaud phenomenon. This is a relatively quick, easy, and low-risk method of treating a patient with incapacitating ischemic pain of the hand. The exact mechanism by which botulinum toxin works in this clinical scenario is still under investigation, but some theories suggest an effect on the vessels and/or nerves of the hand through inhibition of sympathetic nerves, sensory nerves (c-fibers), substance P, and/or other signal transduction pathways. Studies show a 75 to 100% reduction in pain and up to 50% healing of chronic ulcers. Approximately 10 units of botulinum toxin is bathed around each of the digital neurovascular bundles in the palm. The most common side effect reported is temporary minor intrinsic hand weakness. Injecting botulinum toxin in the skin or too proximally in the wrist has not shown the same response as around the digital neurovascular bundles in the palm. Surgical sympathectomies by stripping the adventitia of the digital and wrist vessels have also shown some success in symptom control. Stellate ganglion blocks have also been used for this purpose among others (complex regional pain syndrome); however, local anesthetics, not botulinum toxin, are used to block the ganglion.

Answer 33

The correct response is Option B. Emergent incision and drainage is mandatory for high-pressure paint gun injuries. Although clinically these may appear benign and/or superficial, there is often significant underlying injury. Even small amounts of material can lead to compartment syndrome, poor perfusion, and closed space infections resulting in tissue necrosis and ultimately, amputation. History is critical, but plain films may be used to confirm the diagnosis, as both latex and the less common oil-based paints are easily seen. Grease may be radiolucent or radiopaque, depending on lead content. The most commonly injected materials are paint and grease but can also include paint solvents and fuel oil. Nearly all reported cases involved male occupational injuries and injury to the non-dominant second or third digit, as in this case. These machines can generate pressures of 2,000 to 12,000 pounds per square inch (psi), which far exceeds the 100 psi needed to break the skin. These extreme pressures can propel injected material through the skin and subcutaneous tissues down to the bone or along fascial planes, tendon sheaths, and neurovascular bundles. The overall rate of amputation was 30% and particularly related to the location of injury and type of material injected. Optimal time for wide surgical debridement was within 6 hours of injury. Other studies have documented an amputation rate of approximately 40% when surgery is performed within 6 hours, and an amputation rate of 57% when surgery is delayed beyond 6 hours. The amputation risk is as high as 87% without treatment or if treatment is further delayed. None of the other interventions listed are appropriate for this type of emergent injury.

Answer 34

The correct response is Option B. The minimum stump length required for prosthesis fitting is 5 to 10 cm distal to the elbow. Major upper extremity amputations are defined as amputations at or proximal to the wrist joint. Data from 2005 estimate that upper extremity amputations account for 34% of the 1.6 million people living in the US with limb loss, and 41,000 of these were considered major amputations. Limb salvage is always the goal of the initial surgical management; however, the decision to amputate is made when limb salvage will result in a less functional outcome for the patient. The ideal stump has adequate length, durable soft tissue, minimal edema, and a tapered shape with minimal scar tissue that is not directly over the bony prominence. Muscle preservation is important for the potential use of a myoelectric prosthesis. In order to preserve elbow function and allow for fitting of a prosthesis, at least 5 cm of a bony stump is required. Although shorter transradial stumps do not allow for pronation and supination, preservation of elbow function is felt to be worthwhile functionally. Transfer of the biceps tendon to the ulna should be considered in shorter transradial stumps to decrease the risk of developing a flexion contracture at the elbow. Amputations at least 10 cm proximal to the wrist or at the junction of the middle and distal 1/3 are felt to be ideal in terms of muscle coverage, stability of prosthesis fit, and forearm rotation, but not required. More distal stumps can be problematic in terms of soft-tissue coverage over bone and limb-length discrepancy to accommodate the wrist unit of the prosthesis.

Answer 35

The correct response is Option D. The only factor that correlated with survival in the reported series and reviews is the repair and/or grafting of two or more dorsal veins. Reports that did not compare groups recommend repairing at least two dorsal veins of replanted digits. Smoking, level of amputation, need for skin grafting, and associated fractures were not found to have any effect on survival of digits that had ring avulsion injuries.

Answer 36

The correct response is Option B. The most appropriate method of treatment is excision and repair of the nail bed. The anatomy of the nail consists of a nail plate, nail fold, and a nail bed. The nail bed is the soft tissue beneath the nail plate, which is composed of the germinal matrix proximally and the sterile matrix distally. Most nail plate growth (90%) is provided by the germinal matrix. In cases of trauma, adherence between the nail fold dorsally and nail bed volarly can result in synechiae, interfering with nail growth and resulting in a longitudinal split in the nail. It is important to prevent adherence of dorsal and palmar elements by splinting the nail fold open during the healing phase. This can be accomplished by replacement of the nail plate if available, or using a piece of foil from the suture packet. This patient presents with a split nail deformity after previous trauma. There is scarring between the nail fold and the nail bed, resulting in a longitudinal split with inability to allow for growth of the nail plate in the central portion. Proper treatment consists of excision of the nail bed scar, with repair of the nail bed. Splinting of the nail fold during the healing period will prevent recurrent scarring of the dorsal fold to the palmar surface. In cases where there is significant scar tissue and inability to close the resultant defect after excision, grafting of the nail bed may be required. A split graft of the sterile matrix can be performed if the deficit is only present distally. If the germinal matrix is involved, a full-thickness graft is needed. Avulsion of the nail plate alone will not eliminate the scarring at the proximal nail fold. Oral antifungal therapy is useful in treatment of fungal onychomycosis. Complete excision of the nail bed and split-thickness skin grafting can be used in nail ablation, but would result in absence of the nail and not yield a more cosmetic appearance. Topical phenol application has been used for nail matricectomy, but can produce irregular tissue destruction and would result in loss of the nail.

Answer 37

The correct response is Option D. This patient has a proximal thumb avulsion with disruption of the carpometacarpal (CMC) joint. In this scenario, the best reconstructive option (besides successful replantation) is pollicization of the index finger. Reconstruction after thumb amputation, as with congenital deficiencies, depends largely on the length of the remaining skeletal structure. One can lose most of the distal phalanx and still retain good overall thumb function. Amputations that involve the proximal phalanx or the metacarpal suffer from deficient bone length and procedures that add length, like distraction, toe to thumb, or osteoplastic reconstruction. When the entire metacarpal is absent, the aforementioned procedures will not be effective. Pollicization will restore thumb length and provide very good function.

Answer 38

The correct response is Option B. Radiotherapy has been proposed as a potential treatment to slow or stop progression of Dupuytren contractures (palmar fibromatosis). A prospective study of radiotherapy revealed no greater efficacy than observation as an intervention for slowing the disease process. There is no evidence to suggest radiotherapy for correction of an established contracture. Rijssen and colleagues established quantitative criteria for recurrence, using an increase of total passive flexion contracture of 30 or greater, compared to the 6-week follow-up values in previously treated joints. After 5 years, their recurrence rate following percutaneous needle fasciotomy was 85%; 21% for limited fasciectomy; and 32% of joints successfully treated with Clostridial collagenase. Percutaneous aponeurotomy with lipografting is an experimental technique which has shown some promise with correction of contractures and prevention of recurrence, but the evidence is level 4, with no controlled studies looking at this technique, in comparison to other established techniques. Although limited fasciectomy provides the greatest degree of initial correction for Dupuytren contractures, as well as the longest period prior to recurrence, the costs associated with the procedure are by far the highest. When comparing the QALY costs of three interventions (limited fasciectomy, percutaneous needle fasciotomy, and collagenase injection), limited fasciectomy yielded the highest cost per QALY. The authors emphasize that this does not indicate limited fasciectomy is an inappropriate intervention—only that it is relatively the most expensive.

Answer 39

The correct response is Option E. The most appropriate next step is fasciotomy. The patient is exhibiting signs of compartment syndrome after sustaining a significant crush injury to the lower extremity. Signs and symptoms of compartment syndrome include pain with passive stretch, increased pressure on palpation, paresthesias, paralysis, pallor, and pulselessness. Early recognition and treatment are necessary to prevent permanent damage. The pressure within the muscles increases, and prevents blood flow to the area and capillary exchange of nutrients. Fasciotomy is recommended if compartment pressure exceeds 30 mm Hg, or if the difference between intracompartmental pressure and diastolic blood pressure is less than 30 mm Hg. If left untreated, ischemic necrosis to the muscles can result, causing permanent disability. Compartment pressures can be measured by a handheld manometer, or the method of Whitesides with an arterial line setup. Operative fasciotomy is indicated to release the compartment pressures and prevent tissue loss and muscle necrosis. Loss of pulse typically occurs later in the spectrum of findings. Angiography would be useful in evaluating vasculature and blood flow to the lower extremity. Typically pain with passive stretch does not occur in cases of arterial insufficiency. Duplex ultrasound is used to look for deep venous thrombosis, which can be a source of pain and swelling in the lower extremity. This is more typical in the postoperative period or after prolonged immobilization. In this case, the mechanism of injury would prompt urgent fasciotomy. Compression wrap and elevation are used in treatment of venous stasis and lymphedema, which is unlikely to be the cause of swelling in this case of acute trauma. CT scan can provide better detailed imaging, but would not be indicated in this situation and would delay treatment.

Answer 40

The correct response is Option C. The NEXUS Criteria were developed to help physicians determine whether cervical spine imaging could be safely avoided in appropriate patients. The NEXUS literature defines a distracting injury as “a condition thought by the clinician to be producing pain sufficient to distract the patient from a second (neck) injury.” Similarly, the Canadian C-spine rule describes distracting injuries as “injuries […] that are so severely painful that the neck examination is unreliable.” It also must be recognized that the surgeon and ER staff can be “distracted” by what appears to be the overwhelming injury. Trauma evaluation algorithms strictly apply. A patient involved in a rollover motor vehicle accident has significant mechanism of injury to warrant a complete trauma evaluation. All other answers here are appropriate to prepare for the operating room AFTER the initial trauma clearance is obtained.

Answer 41

The correct response is Option C. In the patient described, the most significant contraindication to replantation is the mechanism (crush injury) and multiple-level nature of the injury. It is highly unlikely that replantation will be successful with a crush mechanism due to the zone of injury. In addition, the multiple-level injury including the proximal phalanx and distal interphalangeal (DIP) joint precludes a functional result. Replantation in children does not adversely affect epiphyseal growth. Children adapt quite well to functional deficits of the hand. Microvascular surgery in children, while challenging, has been shown to have a very high success rate when performed by skilled microsurgeons. The index finger can be considered expendable; however, children tend to have more favorable results than adults when it comes to replantation and, therefore, whenever feasible, replantation should be attempted, even if it is an isolated index finger injury. The mechanism of injury plays a greater role than the type of digit in determining the feasibility of replantation in the pediatric population.

Answer 42

The correct response is Option C. In a patient with an intravenous extravasation, if the symptoms are mild (pain, swelling, or erythema), elevation and cold compresses will usually lead to complete resolution. Patients who have more severe symptoms, such as neurovascular compromise, may need additional evaluation of compartment pressures and potentially surgical exploration for decompression; however, the first step in treatment is still elevation of the extremity. Extravasation injury was once a difficult problem. The extravasation of ionic contrast at high osmolality had increased risk for soft-tissue complications, and plastic surgery consultation was often necessary. The switch to nonionic, low-osmolality contrast over the past decade has resulted in a significant decrease in complications. In a recent study of 69,657 patients undergoing a CT scan, the rate of extravasation was 0.7% (476 patients), and only one patient required operative intervention and decompressive fasciotomy. Corticosteroids do not have a role in extravasation injuries.

Answer 43

The correct response is Option D. The use of collagenase Clostridium histolyticum for Duypuytren contracture has been well studied. Reports of its efficacy and safety have been published in numerous papers in peer-reviewed journals. Though postulated, there have been no cases reported in the literature of digital nerve rupture during cord rupture with collagenase Clostridium histolyticum. Pulley rupture and flexor tendon rupture have been reported. In this case, observation would be the most appropriate next step. It is more likely that there is a neuropraxia rather than a frank rupture of the nerve. Electromyography and nerve conduction velocities will not elucidate whether the nerve has been severed. Exploration and repair is not indicated only 1 week after injury; exploration of a neurapraxia injury is indicated 8 weeks after injury. The best option is to observe the patient's injury.

Answer 44

The correct response is Option C. The homodigital island flap raises skin and fat overlying one digital neurovascular bundle that can be advanced distally to cover a pulp defect. As long as both digital arteries are patent, the flap can be raised on either digital artery on any finger. Because the digital nerve is raised with the flap, the overlying skin retains its sensibility (figures 2b and 2c). The first dorsal metacarpal artery flap raises skin and fat from the dorsum of the proximal phalanx of the index finger based on branches of the radial artery and superficial radial nerve. It is useful in providing sensate coverage of the thumb, but the pedicle is not long enough to allow the flap to reach the tip of a finger. The thenar flap and cross-finger flap raise skin from the thenar eminence and dorsal middle phalanx of a finger, respectively. Innervation is not transferred in coverage with these flaps; sensation recovery must occur with growth of the tissue surrounding the original defect. Both of these flaps require two stages, making them less appealing options. The reverse radial forearm flap is a large, robust flap that provides excellent coverage of the hand. Its pedicle allows it to reach the tip of a finger; however, when raised in a reverse pattern with retrograde vascular flow, the flap would not bring sensation with it. In addition, the flap is too large for the defect shown in the photograph.

Answer 45

The correct response is Option D. The patient described has lost the sterile matrix of the nail bed. The germinal matrix is intact, as the nail continues to grow. The nail bed consists of the germinal matrix proximally and the sterile matrix distally. The sterile matrix allows the nail to adhere to the bed. Observation, amputation, and obliteration of the nail bed do not seem to be good options for a patient who has stated that appearance is paramount. The issue here is that the nail continues to grow, but cannot adhere to the full-thickness skin graft. The best option would be to harvest a split-thickness sterile matrix graft from the big toe. No additional germinal matrix is necessary as the germinal matrix is intact and producing nail.

Answer 46

The correct response is Option E. Loss of the distal fingertip and the associated soft-tissue defect can be treated using different methods, but the involvement of the nail influences the choice of surgical approach and makes reconstruction more difficult. If the sterile matrix is foreshortened and heals to the volar soft tissues, it can result in hook-nail deformity. The germinal matrix is responsible for formation of nail plate elements and injury does not result in hook-nail. The nail groove is the lateral margin of the nail and the site of ingrown nails and paronychia. The eponychium is the cuticle covering the proximal nail plate. Loss of the eponychium results in a rough nail lacking the usual lustre. The lunula is similarly on the proximal nail and is under the plate.

Answer 47

The correct response is Option B. The correct response is that the limb should be cooled until vascular anastomoses are complete. Replantation of an amputated extremity remains the primary option at initial presentation. Contraindications for immediate replantation include an unstable patient who cannot tolerate a prolonged operative procedure, and patients in whom amputation and prosthesis would provide a better functional result than reconstruction. Warm ischemia should not exceed 6 hours, but can be extended to 10 to 12 hours when a part is cooled. Therefore, keeping a replanted part cooled until reperfused is important to success. Clamping vessels in an amputated segment damages vessels needed for microanastomoses. Cold heparinized saline and University of Wisconsin solution are commonly used to flush amputated parts to reduce thromboses and cool the part. Systemic complications are not common with the doses used. Persistent cold intolerance is a complaint of the majority of replanted patients. Unless thrombi are present, it is not routine to flush with thrombolytics. Immersing in saline is not appropriate. When performing vascular anastomoses on larger masses of tissue with a longer ischemia time, performing arterial anastomoses and allowing run-off of metabolites through an open venous system before venous anastomoses are performed is recommended. Arterial perfusion may also be established early, allowing more time for repair of bone and tendon without prolonging ischemia times. Fasciotomies are recommended as periods of ischemia can lead to compartment syndrome. However, these do not need to occur before anastomoses and should not delay reperfusion. Elevation of a replanted part is helpful to reduce post-operative edema but has no role before anastomoses.

Answer 48

The correct response is Option E. While amputations distal through the proximal phalanx may benefit from isolated webspace deepening, it is unlikely that adequate length would remain at this level to provide good pinch or grip function even with a deeper web. Prior to the advent of free-tissue transfer, osteoplastic reconstructions, including the reversed radial forearm flap with inclusion of a radius bone segment, were the workhorses of thumb reconstruction. The resulting thumb, however, is insensate and lacks any motion except at the level of the remaining CMC joint. Aesthetically, this reconstruction looks the least like a thumb when compared to toe transfers. The great toe wrap-around flap provides a cosmetically acceptable way to resurface a thumb when the skeletal support is already present, either due to retention from the trauma or from an osteoplastic reconstruction. In this case, the skeletal support is absent, and the wrap-around flap by itself would not allow recreation of a stable thumb. The great toe free flap provides an excellent reconstructive choice for a sensate, mobile thumb. Functionally, it will be nearly identical to the second toe transfer, and the two have both been used extensively for functional restoration. Aesthetically, the great toe tends to be larger than the contralateral thumb, leading to the development of the "trimmed" great toe transfer. In addition, the cosmetic impact on the foot is greater than that of harvesting the second toe, making this a less aesthetically acceptable reconstruction than the second toe. The second toe transfer offers functionality equivalent to the great toe transfer and creates a thumb closer in size to the contralateral thumb. In addition, the harvest of the second toe avoids sacrifice of the aesthetic unit of the great toe on the foot, a consideration for this patient as she may still wear open-toed footwear.

Answer 49

The correct response is Option C. The most appropriate coverage option for this 1.5-cm defect of the thumb is a Moberg flap. The Moberg flap has an axial pattern blood supply. It is indicated for defects as great as 1.5 cm on the volar surface of the thumb. It provides sensate soft-tissue coverage of thumb tip wounds. The VY advancement flap will not cover defects as large as 1.5 cm; and the cross-finger flap, although it will cover defects as large as 1.5 cm, is inferior to the Moberg flap for defects of this type. It also does not carry innervated tissue, making the Moberg flap the most appropriate flap option for this defect.

Answer 50

The correct response is Option C. The correct treatment for this deformity would be excision of scar and repair of the nail germinal and sterile matrices, which had not been done initially. Usually, removal of scar tissue and undermining will allow for delayed primary closure. Grafting of the nail bed should not be necessary. Trephination is done only in the acute setting to evacuate hematoma, if the subungual hematoma is symptomatic. The nail plate grows at 3 mm per month; therefore, full-length nail growth would require 3 to 4 months. Because this deformity has occurred 6 months after the injury, the nail plate has completed a full growth cycle. Nonsurgical treatment would therefore be incorrect. Nail bed ablation, also called matricectomy, is complete chemical or surgical ablation of the nail matrix and is used for recalcitrant and recurrent fungal infections. Matricectomy is also used in painful post traumatic conditions such as pincer or split nail deformities. A wrapped toe procedure is a microsurgical replacement of soft tissue to an amputated finger, and can include nail matrix and surrounding soft tissue replacement, but is not indicated in this setting where only the nail matrix is involved.

Answer 51

The correct response is Option E. Skin is the most reactive component of vascularized tissue allograft. Initial response is an acute rejection, which is modulated by type II hypersensitivity. This is when IgG and IgM antibodies bind to the offending cell, targeting it for destruction by the immune response. Dr. Joseph Edward Murray, plastic surgeon and Nobel Laureate who performed the first human kidney transplant in 1954, elucidated the difficulty in suppressing skin immunogenicity. In fact, the first hand transplant was performed in Ecuador in 1964; however, it quickly failed because of acute rejection. This demonstrated that although the technical ability of vascularized allografting was possible, the medical knowledge of transplant immunology was not yet advanced enough for success. Since it contains antigen-presenting cells such as Langerhans cells, skin is quite immunogenic and current therapy and monitoring of upper extremity vascularized composite allograft relies on skin monitoring to detect for acute rejection. Interestingly, although the skin may be in the process of being rejected, other tissue components of the vascularized composite allograft do not appear to suffer the same amount of immune-modulated damage.

Answer 52

The correct response is Option C. Of the choices given, the most likely complication of brachial artery catheterization is paresthesia to the lateral three digits due to median nerve injury. The median nerve travels adjacent to the brachial artery along its length of the arm until the two separate deep to the bicipital aponeurosis and is thus subject to unintended injury in the course of attempted cannulation in the distal arm. Progressive clawing of the ring and little fingers, and transient loss of wrist and finger extension, manifesting ulnar and high radial nerve injuries, respectively, have not been described as complications of brachial artery catheterization. Common sites of arterial catheterization in adults include the radial, femoral, brachial, dorsalis pedis, and axillary arteries. Complications common to all sites include local and systemic infection, catheter thrombosis, bleeding, hematoma, and pain. One prospective cohort study involving almost 2500 patients found that femoral artery catheters were associated with increased incidence of both local infection and bloodstream infection when compared with radial arterial catheters. A significant relationship between other anatomical sites of arterial catheterization and increased incidence of infection has not been shown in other large studies. There is a decreased risk of catheter thrombosis in larger caliber vessels like the brachial artery compared with smaller vessels such as the radial artery. Other risk factors for catheter thrombosis include duration of catheterization greater than 72 hours, larger gauge catheters, low blood flow states, peripheral artery disease, and vasospastic disorders.

Answer 53

The correct response is Option E. This is a lumbrical plus finger as a result of amputation of the long finger at the distal third of the middle phalanx. The flexor digitorum profundus (FDP) tendon has retracted, increasing tension on the lumbricals during flexion through the FDP tendon. This leads to paradoxical extension of the proximal interphalangeal (PIP) joints with attempted flexion of the digit. Division of the lumbrical to the long finger will solve this problem. PIP joint arthrotomy is not necessary, as this is not a PIP joint flexion or extension contracture. The scenario described insinuates this by providing the information about the passive range of motion as compared with the active range of motion at the PIP joint. Flexor tendon adhesions do not lead to paradoxical extension with attempted flexion. Therefore, flexor tenolysis will not improve the range of motion of the PIP joint. The PIP joint has full passive flexion and an ability to extend at the PIP joint, making significant extensor adhesion less likely, and therefore, extensor tenolysis a less worthwhile procedure than lumbrical release to address this issue. Division of the FDP tendon will not improve flexion of the long finger PIP joint or address the paradoxical extension at the PIP joint. Revision amputation of the long finger will not address the paradoxical extension at the PIP joint.

Answer 54

The correct response is Option A. The patient’s presentation is classic for hypothenar hammer syndrome, or trauma-induced thrombosis of the ulnar artery. This condition is significantly more common in men than in women (9:1), peaks in incidence between 40 and 60 years of age, and is often associated with vocational (e.g., carpenter, machinist, mechanic) or recreational activities (e.g., golf, baseball catchers) that subject the ulnar base of the palm to repeated vibration or blunt trauma. Unlike thromboangiitis obliterans (Buerger disease) or Raynaud disease, the presenting signs and symptoms are almost always unilateral and localized to the ulnar side of the hand and can include pain over the hypothenar eminence, cold sensitivity, paresthesias in the ring and little fingers, blanching and slow capillary refill in the ring and little fingers, and possible positive Allen test. Occasionally, there may be an aneurysm (pulsatile mass) in the ulnar tunnel. Nonoperative treatment, such as activity modification, is effective in many cases, but persistent symptoms or the presence of an aneurysm may warrant resection of the involved area with vein grafting. Buerger disease is an acquired vasculitis that occurs almost exclusively in smokers. It is typically bilateral, not localized to the ulnar side of the hand, more common in males (3:1) between the ages of 30 and 45 years, and progresses from intermittent claudication to severe ischemia with ulceration and necrosis of the affected fingers. Raynaud disease is an idiopathic vasospastic disorder that is more common in females under the age of 40 years. This typically affects all fingers and is often bilateral. Symptoms include acute episodes of blanching and lack of blood flow (white fingers), followed by cyanosis (blue finger discoloration), and eventual rapid reperfusion and hyperemia (fingers turn bright red). Ulnar tunnel syndrome refers to compression of the ulnar nerve in the ulnar tunnel, often by a ganglion cyst. While ulnar nerve compression can be a component of hypothenar hammer syndrome, this diagnosis does not include an ischemic presentation as portrayed in the case. Thoracic outlet syndrome is neurovascular compression of the subclavian vessels and brachial plexus. This condition can present with upper extremity cold intolerance and sensory symptoms localized to the ulnar nerve, but the symptoms are usually more diffuse, and vascular compromise is rare and not specific to the ulnar hand.

Answer 55

The correct response is Option D. The most likely muscle to sustain damage is the flexor digitorum profundus. The patient described has signs of compartment syndrome, resulting from a tight cast and swelling due to the fracture. Early recognition and treatment is necessary to prevent permanent damage. The pressure within the muscles increases and prevents blood flow to the area and capillary exchange of nutrients. Fasciotomy is recommended if compartment pressure exceeds 30 mmHg, or if the difference between intracompartmental pressure and diastolic blood pressure is less than 30 mmHg. If left untreated, ischemic necrosis to the muscles can result, causing Volkmann ischemic contracture. This gives rise to scarring and permanent shortening of the muscles. The deep muscles of the forearm, the flexor digitorum profundus, and flexor pollicis longus are the first to sustain damage. If the condition continues, all muscles of the forearm can be involved. The hand is left in a contracted intrinsic minus configuration, with severe disability. The more superficial muscles (flexor digitorum superficialis) are less likely to be affected than the deep muscles. The extensor muscles (extensor digitorum communis, extensor pollicis longus, and extensor carpi radialis brevis) are the last to be involved in Volkmann ischemic contracture.

Answer 56

The correct response is Option A. Hook-nail deformity is a volar curvature of the nail that occurs because of lack of bony support to the sterile matrix. Hook-nails most commonly occur after trauma. The best means of prevention is ensuring that the distal limit of sterile matrix is a minimum of 2 mm proximal to the distal phalanx tip. Reconstruction includes grafting, local and regional flaps, and distal flaps. Bone grafting (free, vascularized or phalanx osteotomy) is another option. Bone grafting has the highest failure rate due to reabsorption. Free vascularized nail flaps, arterialized venous nail flaps, and osteo-onychocutaneous nail flaps are another option.

Answer 57

The correct response is Option D. Collagenase injection has been FDA-approved for the treatment of Dupuytren contractures with palpable cords and works by dissolving collagen contained in the cord. Injection is typically performed with placement of collagenase along several areas along the Dupuytren cord using a hubless 1-mL syringe, followed by a finger extension procedure approximately 24 hours after injection. Care should be taken to avoid injecting into tendons, nerves, blood vessels, or other collagen-containing structures. Injection of the 20-degree contracture of the little finger proximal interphalangeal (PIP) joint is most likely to result in serious complications. Dupuytren contracture is a disease resulting in progressive contracture of the palmar fascia. The disease involves activity of myofibroblasts and has a genetic component, being more common in people of northern European descent. Treatment of PIP contractures of the little finger is most likely to result in serious complications. There have been a few incidents of flexor tendon rupture occurring from collagenase injections, and these are thought to occur due to the proximity of the flexor tendon to the Dupuytren cord. Care must be taken to keep the collagenase injection away from the flexor tendon in this finger. Recommendations for collagenase injections for PIP contractures in the little finger include keeping the injection no more than 2 to 3 mm deep and as close to the palmar digital crease as possible, staying no more than 4 mm distal to the palmar digital crease. Serious complications are not found to be more frequent in other digits or in the metacarpophalangeal (MCP) vs. PIP joints (other than in the little finger PIP joint). The degree of contracture does not have a bearing on the incidence of serious complications.

Answer 58

The correct response is Option A. The microvascular reconstruction of choice is a toe-to-thumb transfer involving the great toe. The most common arterial pedicle for this composite flap is the first dorsal metatarsal artery (~70%), a branch of the dorsalis pedis artery. The great toe can be harvested en bloc, as a trimmed flap to improve size match, or as a wrap-around soft-tissue flap for more distal or soft-tissue–only reconstructions. Less commonly, there is a dominant plantar arterial system from the plantar digital arteries via the lateral plantar artery. Communications between the dorsal and plantar systems exist between the metatarsals, and a flap with plantar-dominant inflow can be traced back to the dorsalis pedis in most cases, although the dissection is tedious. Many authors recommend vein grafting if more length is needed in a plantar-dominant flap. This patient requires mostly restoration of length and sensibility. Reconstruction with a toe-to-thumb transfer has the advantages of transferring similar glabrous tissue with good cosmetic match. Flexion, extension, and sensation can be restored with good outcomes, according to the literature. This patient has an intact carpometacarpal joint and adequate range of motion should be maintained. The lateral plantar artery is the arterial pedicle for the medial plantar artery fasciocutaneous flap. It does not contribute to the plantar arch. This flap is used mostly as a pedicle flap for coverage of defects on the forefoot and heel. It can be used for free tissue transfer. The deep plantar arch is an anastomotic network between the lateral plantar and dorsalis pedis arteries. The peroneal artery is the pedicle for the free fibula osteocutaneous flap; however, this is not described for use in thumb reconstruction. Osteoplastic reconstruction for thumb defects not involving the basilar joint have been described as both pedicle and microvascular free flaps. These involve a vascularized soft-tissue flap surrounding a nonvascularized bone graft. The radial artery is the pedicle for the radial forearm flap, which can be harvested as a soft-tissue flap around an iliac crest bone graft, or as an osteocutaneous flap. The superficial circumflex iliac artery is the pedicle for the groin flap. This is mostly described as a staged pedicled flap for osteoplastic reconstruction around an iliac crest bone graft. Both of these techniques are complicated by poor return of sensation and bone resorption. They should be used as second-line options when free toe transfer or pollicization is not available due to severity of injury or other patient-related concerns.

Answer 59

The correct response is Option A. The patient described sustained a crush injury, and subsequently experienced increased pain in the affected extremity. He ultimately experienced pain upon passive motion as well. This scenario should elevate suspicion for compartment syndrome. Other signs and symptoms of compartment syndrome include paresthesias, which this patient did not have, as well as poikilothermia, and pulselessness, which is a late finding. Compartment syndrome can be the result of high-impact trauma or low-impact injury, and it should be identified as early as possible to prevent permanent disability. Therefore, the next best step in the care of this patient is measurement of compartment pressures to determine if fasciotomy is necessary to release the build-up of pressure in the forearm. Radiological imaging will waste time and possibly worsen the patient’s prognosis. Urinalysis should be performed as part of the patient’s overall workup in order to assess the potential for acute tubular necrosis, but it is not the definitive next step.

Answer 60

The correct response is Option D. The most consistent clinical stage of rejection in this case is hyperacute rejection. In hyperacute rejection, the transplanted tissue is rejected within minutes to hours because of preformed antibodies in the recipient. These antibodies are usually induced by previous blood transfusions, multiple pregnancies, or previous transplantation. The antigen-antibody complexes activate the complement system, causing massive thrombosis in the capillaries, which prevent the vascularization of the graft. If the graft is not removed, severe systemic complications such as systemic inflammatory response syndrome will result. Acute humoral rejection is also primarily mediated by antibody and complement, similar to the hyperacute form of rejection. However, these antibodies are not preexisting, but rather are rapidly induced after exposure to the graft. This usually takes a few days, and the rejection appears in about 3 to 7 days. Another important difference between the hyperacute and acute form of rejection is that there is no known treatment for the former, while the latter may be reversed by plasmapheresis and treatment with anti–B-cell reagents. Acute cellular rejection is mediated by T cells that have been activated against donor antigens, primarily in the lymphoid tissues of the recipient. This is the most common form of rejection treated by clinicians and usually occurs in the first 3 to 6 months of the transplant. Acute cellular rejection is usually treated with increased doses of standard immunosuppressive drugs or anti-lymphocytic antibodies. Chronic rejection develops months to years after acute rejection episodes have subsided. Chronic rejections are both antibody- and cell-mediated. The use of immunosuppressive drugs and tissue-typing methods has increased the survival of allografts in the first year, but chronic rejection is not prevented in most cases.

Answer 61

The correct response is Option B. When multiple digits are amputated, thumb replantation takes priority. If the amputated thumb is not suitable for replantation, the best available finger is replanted in its position. If there are injuries to other fingers or parts of the hand, they should be repaired first before replantation. In a mutilated hand, functional preservation takes priority. Procedures that ensure maximal function must be done first because the hand should not be disturbed after replantation. The sequence of repair of structures in multi-digit replants can be performed either digit-by-digit or structure-by-structure. While structure-by-structure is more efficient, warm ischemia time tends to be longer. If the thumb is involved, it is preferred that the thumb be replanted first followed by the remaining digits. After debridement, vessels and nerves should be identified and tagged because they may be more difficult to locate after bone fixation. The sequence usually is bone fixation, tendon repair, and then vessel and nerve repair. Bone shortening facilitates repair of structures without tension. Bone fixation is performed first and should be stable enough to undergo the rigors of hand therapy. After bone fixation, the volar structures are repaired by structure type (i.e., flexor tendon, then the artery and nerves) followed by the dorsal structures (extensor tendon and veins).

Answer 62

The correct response is Option B. The patient described is presenting with the signs and symptoms consistent with compartment syndrome of the upper extremity. It is still early in the process but time is running out on being able to save muscle and function. The patient must be resuscitated and is likely intravascularly depleted. Of the options presented, the next best option would be to take the patient to the operating room for exploration and decompression of the arm, forearm, and possibly hand. While compartment pressures could be helpful, with this clinical picture, it is important to make a clinical diagnosis and move forward with treatment. Observation might be indicated if there were a delayed presentation in which there is the theoretical risk of increasing infection without restoring function. However, one should typically err on the side of decompression in the hope of saving muscle and function. Imaging studies are not indicated for compartment syndrome.

Answer 63

The correct response is Option E. Although daily dressing changes are appropriate for fingertip injuries with one dimension measuring 1 cm or less, the exposed bone makes this less appropriate due to the increased risk of infection with prolonged bone exposure. A split-thickness skin graft would adequately cover the defect, but padding over the bone may not be sufficient and sensory recovery would not be as good as with a flap. Use of an Atasoy volar V-Y advancement flap is ideal in transverse and dorsal oblique fingertip amputations, particularly those with bone exposure where durability and padding might be a consideration. In addition, Atasoy flaps provide excellent sensation as the neurovascular supply is not interrupted. The Atasoy flap is contraindicated in volar oblique fingertip amputations, as advancement in these amputations would be inadequate. A groin flap would provide excellent durability and padding, but would be an extreme option where local flap reconstruction is available and preferred. The Moberg flap is for thumb tip injuries. The cross-finger flap is for volar defects.

Answer 64

The correct response is Option A. When approaching post-traumatic thumb reconstruction, two of the most important factors in determining treatment are the residual length and relative function of the remaining thumb. In this patient with a distal amputation and good active range of motion, the simplest and most beneficial procedure would be web-space deepening via a four-flap Z-plasty. Simple Z-plasty and dorsal rotational flaps can also serve to deepen the first web, but the most commonly used technique is the four-flap Z-plasty. Groin flap can address soft-tissue defecits that this patient does not have. Instances involving contractures of the first web space frequently require release or resection of some of the first web musculature, including the first dorsal interosseous. In a supple thumb with good abduction, this would not be necessary. Pollicization of the index finger or the stump of an index finger can be useful when amputation occurs in the proximal third of the thumb. In the setting of a healthy index finger, however, amputations through the metacarpal would likely be best handled via toe-to-thumb transplantation. Heterodigital island flaps are one method of restoring glabrous, sensate skin to the palmar surface of the thumb. Such flaps were useful primarily when trying to restore sensation to a thumb reconstructed through osteoplastic techniques. This flap would not add length to the thumb or serve to deepen the web space.

Answer 65

The correct response is Option E. Allen classification includes Zone 1: no bone fragment; Zone 2: injury through the sterile matrix with preservation of at least one-half of the nail bed; Zone 3: shorter nail bed remnant; Zone 4: proximal to the dorsal fold; and Zone 5: through the distal interphalangeal joint. The hyponychium is the skin distal and volar to the nail. The perionychium includes the nail, nail bed, and the surrounding skin. The paronychia are the lateral nail folds. The eponychium is the dorsal nail fold, which is proximal to the nail fold. The sterile matrix is distal to the lunula. The germinal matrix contributes 90% of new nail growth and ends at the lunula. The extensor terminal tendon inserts 1.2 to 1.4 mm proximal to the germinal matrix.

Answer 66

The correct response is Option B. Nonadherence of the nail is the most common nail deformity after trauma and is usually distal to scarring in the nail bed or bone irregularities. The most common cause of nonadherence is nail bed scarring. The scar interrupts the progressive addition of nail cells from the sterile matrix to the volar nail plate, causing detachment of the nail. The nail is then unable to attach to the nail bed distally. Distal nonadherence of the nail may lead to subungual hygiene problems, an unstable nail when manipulating small objects or pain, when catching the nail on objects. Nonadherence is treated by removing the nail plate and excising the underlying scar. The area of scar resection can then be closed primarily or closed with a split-thickness sterile matrix graft if the defect is too large. Malalignment of distal phalanx fractures may cause or contribute to nonadherence. The exostosis should be removed to form a flat surface for the sterile matrix and subsequent nail adherence.

Answer 67

The correct response is Option C. Myofibroblasts act on the collagen bundles deposited by fibroblasts to cause alignment into a cord and shortening of the cord. These cells also secrete extracellular matrix components that remodel in a shorter configuration, creating durability of the contracture. More mature cords are believed to be less cellular. Macrophages are believed to act on the extracellular matrix but do not produce contracture. Striated myocytes are in skeletal muscle and are not involved in Dupuytren disease. Merkel cells are a sensory end-organ and are not involved in Dupuytren disease. Stem cells including adipocyte progenitors are known to exist in Dupuytren cords. They are hypothesized to develop into cells that affect the cord. There is no evidence that these cells act on Dupuytren cords while they are still stem cells.

Answer 68

The correct response is Option D. In the patient described, the most appropriate next step is microvascular replantation. The thumb is an important part of hand function, and thumb amputations at all levels are good indications for replantation. Length and stability of the thumb are important in forming a radial post, and the thumb takes priority in replantation. The patient is otherwise healthy, and there are no medical comorbidities or other injuries that would interfere with the replantation effort. With thumb amputation sustained at the level of the metacarpophalangeal (MCP) joint, the remaining thumb will be too short for adequate function if length is not restored. Although there may be some soft-tissue injury as a result of the saw, bone shortening may be considered to get out of the zone of injury, and vein grafts may be employed if necessary. A groin flap can be used for soft-tissue coverage, but it requires the hand to be attached to the groin for a period of time. This can result in stiffness of the other digits, and requires a staged procedure. It would not restore length in this case. With failed replantation, it may be used for coverage, or form a component of osteoplastic thumb reconstruction. The Moberg flap or volar advancement flap can be used for coverage of soft-tissue defects of the thumb. This is based on the neurovascular bundles of the thumb, and is used in amputations distal to the interphalangeal joint. The flap typically can cover an area up to 2 cm in size. The Moberg flap would not be available in this case, as it is contained in the detached segment. A reverse radial forearm flap can be used for coverage of soft-tissue defects in the hand. This does require sacrifice of a major vessel to the hand. Although this flap can be used to provide coverage for soft-tissue defects, it will not preserve length of the thumb. In the case of failed replantation with bony exposure, this flap can be employed for coverage before further thumb reconstruction. A well-planned amputation should be considered a reconstructive procedure, and can return a patient to functional use of the hand. Goals include preservation of functional length, provision of durable coverage, preservation of sensibility, prevention of neuromas, prevention of joint contractures, minimal morbidity, early prosthetic fitting, and early return to activities of daily living. In the setting of a thumb amputation at the MCP level, the lack of a thumb will result in marked impairment of hand function. If the replantation effort fails, revision amputation may be an option, with thumb reconstruction later attempted by toe-to-thumb transfer.

Answer 69

The correct response is Option E. The decision to proceed to surgery is based on the patient’s functional limitations and severity of joint contracture. A metacarpophalangeal (MCP) joint contracture of less than 30 degrees or any proximal interphalangeal (PIP) joint contracture is considered an indication for surgery. The MCP joint is rarely a problem since it can almost always be released by a simple fascial excision. If the PIP joint remains in fixed flexion, the checkrein should be examined and released. These are two ligamentous cords lying anterolaterally and running from the proximal swallowtail extensions of the volar plate to the neck of the proximal phalanx. The next structure to be released is the accessory collateral ligament running from the condyle on the head of the proximal phalanx to the lateral edges of the volar plate. Lastly, gentle manipulation may be utilized to obtain some release. Forcefully placing the joint in extension with Kirschner wire fixation is not indicated. Collagenase will not address capsular issues.

Answer 70

The correct response is Option C. Management of ring avulsion injuries remain controversial. Microvascular replantation is a challenging prospect in the setting of a ring avulsion injury and is often associated with the highest failure rates following replantation. This is likely secondary to the mechanism of injury that leads to destruction of the intimal layer of the supporting vasculature. The most appropriate next step in management of the patient described is a ray amputation, which involves removal of the entire digit and most or the entire metacarpal. Completely removing the digit eliminates the segmental loss and greatly improves both function and aesthetic appearance. A well-planned amputation should be considered a reconstructive procedure and can return functional use of the hand to the patient. Revision amputation near or at the metacarpophalangeal joint level leaves a large gap between digits and can lead to functional problems such as dropping small objects through the defect. Skin grafting over exposed bone and tendon is unlikely to be successful. A groin flap can be used for soft-tissue coverage but requires the hand to be attached to the groin for a period of time. This can result in stiffness of the other digits and requires a staged procedure. Replacing the ring finger with a toe-to-hand transfer is impractical, as the transferred digit would be significantly shorter than the adjacent digits and would ultimately impair their function. This technique is suitable for patients who have sustained amputations of the thumb or of multiple digits.

Answer 71

The correct response is Option C. Hypothenar hammer syndrome (HHS), or ulnar artery occlusion at the wrist, involves reduced or no flow to the areas supplied by the ulnar artery. Typically due to arterial occlusion, angiography may show areas of stenosis and ectasis (“corkscrew” pattern). In either case, there are symptoms related to arterial insufficiency. Treatment options range from medical to surgical. Indications for surgery include digital ulceration (a late finding) and distal brachial index (DBI) of less than 0.7. Surgery may involve simple ligation and resection or require reconstruction. Typical indications for surgical reconstruction include inadequate collateral flow or inadequate circulation. Some authors suggest that a preoperative DBI of less than 0.7 is an indication for reconstruction, although others state the DBI needs to be measured after arterial ligation/excision. HHS may initially be approached with medical treatment, but the presence of ulceration and a DBI of less than 0.7 indicate the need for surgical intervention. Raynaud disease is a vasospastic disorder which would give similar findings to HHS, except that it would not be limited to just the ulnar digits.

Answer 72

The correct response is Option B. The perionychium includes the nail bed, nail fold, eponychium, paronychium, and hyponychium. The nail bed includes the germinal matrix proximally and the sterile matrix distally. The nail fold consists of a dorsal roof and ventral floor. The ventral floor is the germinal matrix portion of the nail bed. The germinal matrix produces about 90% of the nail. The sterile matrix adds a thin layer of cells to the undersurface of the nail, keeping the nail adherent to the nail bed. Scarring of the germinal matrix leads to absence of the nail, whereas injury to the sterile matrix leads to nail deformity. Nail growth averages about 0.1 mm/day. Nail appearance is not normal for approximately 100 days after injury. Approximately 50% of injuries are associated with a distal phalanx fracture.

Answer 73

The correct response is Option C. In patients who have sustained an amputation of the thumb and replantation is not possible, optimum strength and function are achieved with the toe-to-thumb transfer. The great or second toe may be chosen, depending upon the preference of the patient and the surgeon. The transfer of the great toe gives a more aesthetic thumb reconstruction, but a greater deficit on the foot. Second-toe transfer yields a smaller thumb but a minimal defect on the foot. In a patient who wishes to preserve grip strength, long finger pollicization would yield a weaker grip. Long finger pollicization is not reported. Distraction osteogenesis is useful for amputations at the proximal phalanx or more distal. For proximal amputations, distraction does not allow sufficient length to achieve power grip. Ring-to-thumb neurovascular island transfer is a procedure to gain sensation to an insensate thumb and does not provide bony reconstruction A digital advancement (Moberg) flap can provide coverage for amputations at the distal phalanx of the thumb. Boney reconstruction is not provided. An amputation at the metacarpophalangeal joint level is too proximal for a digital advancement flap to be useful.

Answer 74

The correct response is Option B. The most appropriate management is coverage with a first dorsal metacarpal artery flap. The patient described has sustained a soft-tissue defect of the digit with exposed bone. Given the size of the defect and the exposure of bone, soft-tissue coverage is warranted. The first dorsal metacarpal artery flap is an island flap of tissue based on the first dorsal metacarpal artery. This can provide sensate soft-tissue coverage to the thumb in a single stage, with inclusion of radial sensory nerve branches. The cross-finger flap involves using dorsal skin of an adjacent finger to resurface the palmar soft-tissue defect. This will allow for coverage of the defect, but requires a two-stage procedure with immobilization of the two fingers which are sewn together, and can result in marked joint stiffness. Although use of the cross-finger flap is possible, it is more useful in younger patients where stiffness would be less of a concern. The Moberg volar advancement flap is based on the neurovascular bundles of both ulnar and radial aspects of the digit. This is useful for reconstruction of thumb defects, but there is not sufficient mobility for use in the other digits. Typically, the Moberg flap can cover an area up to 2 cm2, but can result in interphalangeal joint contracture. Observation alone is possible for defects of up to 1 cm2 but would not be advised in this patient with a larger defect and bony exposure. Skin grafting will likely be unsuccessful with bony exposure and would not restore soft-tissue padding to the area.

Answer 75

The correct response is Option C. The most appropriate prophylactic antibiotic to initiate in this patient is ceftriaxone. Leech therapy is associated with Aeromonas species infections with incidences quoted in the literature from 2.4 to 36.2%. The most common clinical presentation of Aeromonas infection in humans is of cellulitis, often with a foul odor, complicated by subcutaneous abscess formation. In severe cases, extensive tissue loss and septicemia have been reported. Of most concern to microsurgeons is the ability of Aeromonas to invade the walls of blood vessels with resultant vasculitis, thrombosis, and hemorrhagic necrosis. Aeromonas species produce beta-lactamase, so penicillins and first-generation cephalosporins, like cefazolin, are ineffective. High levels of resistance to tetracyclines and amoxicillin-clavulanate (Augmentin) have also been observed. These organisms are usually sensitive to second- and third-generation cephalosporins, aminoglycosides, chloramphenicol, fluoroquinolones, and trimethoprim. The use of fluoroquinolones in children has been limited because of the potential of these agents to induce arthropathy in juvenile animals and to potentiate development of bacterial resistance. Fluoroquinolone use should be restricted to situations in which there is no safe and effective alternative to treat an infection caused by multidrug-resistant bacteria or to provide oral therapy when parenteral therapy is not feasible and no other effective oral agent is available. Doxycycline is contraindicated in children younger than age 8 years, as it may cause permanent discoloration and altered development of teeth.

Answer 76

The correct response is Option D. This is a classic presentation for the patient who develops an ulnar artery aneurysm at Guyon canal. The aneurysm typically is the source of small emboli that tend to affect vessels at the ulnar aspect of the hand and fingers. The emboli cause decreased flow, cold sensitivity, ischemic pain and rubor in the small and ring fingers most commonly. This problem occurs most often in men in their 40s, who suffer repetitive blunt trauma to the hand. Some use their hand as a hammer at work. Other forms of blunt trauma have been linked to this problem, including certain sports and weight lifting. The treatment options include oral medications for vasodilation, cessation of the offending physical activity, smoking cessation if present, sympathectomy, thrombolytics, and either exclusion of the aneurysm and ulnar artery ligation in the palm, or aneurysm excision and vascular reconstruction. Raynaud disease is not the best answer because this presentation with embolic disease localized to the ulnar fingers and the palpable pulse/mass (aneurysm) in the hand are not consistent with Raynaud disease. Patients with Raynaud disease typically present complaining of cold sensitivity, periods of finger blanching, followed by diffuse return of flow to the fingers and pain. Raynaud disease is a diffuse sympathetic problem, not a local aneurysmal problem. Congenital vasospastic disease is not the best answer because the patient in this vignette has no symptoms prior to 3 weeks ago. A congenital vasospastic problem would have presented before, and would be unlikely to be so localized. Distal embolization from the heart is wrong for similar reasons: emboli from the heart would be very unlikely to present unilaterally, in two fingers, adjacent to one another. There would very likely be other symptoms and sites of embolization. Buerger disease is not the best answer for a few reasons. The patient in this vignette is a nonsmoker. Thromboangiitis obliterans (TAO), or Buerger disease, is an inflammatory arteritis seen in smokers. It improves or stops progressing with smoking cessation. Buerger disease does not typically present with such isolated symptoms, and can involve the lower extremities as well.

Answer 77

The correct response is Option B. The hyponychium is the junction of the nail bed (sterile matrix) and fingertip skin beneath the distal free margin of the nail. It consists of a keratinous plug and contains large numbers of polymorphonuclear leukocytes and lymphocytes. It is the first barrier of defense, preventing microorganisms from invading the subungual region. The perionychium extends along the lateral borders of the nail. The eponychium is the distal part of the nail fold where it attaches to the surface of the nail. The lunula is the white arc just distal to the eponychium and marks the distal end of the germinal matrix of the nail bed. It is caused by nail cell nuclei in the germinal matrix as they stream distally and upwards, creating a difference in light reflection between this area and the more distal pink sterile matrix. The nail overlying the sterile matrix, on the other hand, is pink since the nuclei within the nail cells have disintegrated. The nail beyond the point of the lunula is thus clear and the blood vessels of the nail bed show through, giving that part of the nail a pink color.

Answer 78

The correct response is Option B. In patients with traumatic amputations of the thumb, optimal reconstruction is provided by replantation. Vein grafts from the princeps pollicis artery, in the anatomical snuff box, are often required because of the difficult positioning. Vein grafts can be harvested from the foot or the forearm. For injuries at the metacarpophalangeal joint level, no reconstruction method approximates that of the replanted thumb. All efforts should be utilized in order to salvage the amputated thumb. In contrast, for index finger amputations, any surgery which would not provide normal or near normal function often only serves to hamper hand function. A traumatic injury which involved the index finger metacarpophalangeal (MCP) joint would require arthrodesis. A fused MCP joint would only get in the way and detract from function. Option (A) replantation of the thumb and index segment is not correct because of the decreased function which would be observed after a replantation of a poorly functioning index finger. Option (B) is the correct answer. Option (C) is incorrect and since it involved the amputation of both the thumb and index finger. Option (D) “on-top plasty” is a procedure which involves a non-vascularized bone graft covered with a local pedicle flap; this would not provide optimal function. Option (E), which is pollicization of the thumb to index finger, would be suboptimal. Pollicization would only be an option if the thumb were deemed unreplantable.

Answer 79

The correct response is Option C. In this patient with exposed tendon denuded of tenosynovium (as evidenced by the photo and failure to granulate) flap coverage with the first dorsal metacarpal artery flap, or “kite” flap, will provide closure of the wound with similar skin to what has been lost with minimal morbidity. Apart from reaching the thumb dorsal surface, this flap has been successfully used to resurface palmar wounds of the thumb. Photographs of the flap are shown. Alginate dressings would keep the wound moist but would not add to the conservative management of dressing changes the patient has already tried. Skin-graft take relies on adequate granulation tissue in the recipient site to survive. Here neither split- nor full-thickness grafts would be likely to take. Furthermore, grafts directly to tenosynovium can limit tendon excursion after healing. Cross-finger flaps are useful for resurfacing the palmar defects of adjacent digits. Reversed/turnover cross-finger flaps, or cross-finger fascial flaps, can resurface adjacent digits. Wound closure then requires skin grafting of the fascial flap at the recipient site.

Answer 80

The correct response is Option C. Volkmann ischemic contracture can evolve from an untreated acute injury or fracture, blunt or sharp. In the scenario described, the patient appears to have passed out on his forearm, inebriated, possibly compounded by drug use. He presents in a delayed fashion with an early or partial Volkmann ischemic contracture. Essentially, this item tests the examinee’s basic knowledge of which parts of the forearm musculature are most sensitive to internal pressure and ischemic injury. Useful classification systems that correlate well with clinical examination include the Tsuge and Holden classifications. The Tsuge classification basically describes a predictable injury pattern based on the relative susceptibility of different muscles in the forearm to ischemia and pressure. Essentially, the deeper compartments are the most susceptible. A mild Tsuge type affects the flexor digitorum profundus first. The moderate type involves the rest of the deep flexor compartment and begins to affect the superficial flexor compartment. Severe Tsuge type involves the complete deep and superficial flexor compartments, as well as the extensor compartment and mobile wad to varying degrees. Therefore, in this case, the correct response is the flexor digitorum profundus because it is the most sensitive muscle group to a Volkmann ischemic contracture generating insult. A complementary classification system is the Holden classification. The Holden Type 1 classification essentially describes contractures of varied severity caused by injuries proximal to the injured forearm muscles. Examples include a brachial artery thrombosis or a humeral fracture leading to vascular injury and a Volkmann ischemic contracture distal to the site of the initial injury. The Holden Type 2 classification describes direct injuries to the fascial compartment of varied severity, such as prolonged direct pressure, as in the scenario described. Other examples would be direct crush injuries or severe radial and ulnar fractures.

Answer 81

The correct response is Option C. Following a protracted course of tissue ischemia, reperfusion will lead to soft-tissue and muscle edema, and there is a very high risk of compartment syndrome. Routine prophylactic fasciotomy after arterial repair has been questioned. Nevertheless, an extended warm ischemia time of greater than 8 hours and a combined injury involving both major arteries and veins have been proposed as indications for this procedure. In this scenario, the patient has both of these risk factors for reperfusion compartment syndrome, and fasciotomy of the hand and forearm should be performed before leaving the operating room. Wound management, splinting, intravenous administration of antibiotics, and monitoring of hand perfusion are important postoperative modalities, but they are not as temporally relevant as fasciotomy. The use of thrombolytic agents is not indicated in this setting because the perfusion was restored and there is no reason in the vignette to suspect evolving thrombus formation. The routine use of anticoagulant after uncomplicated vessel repair is controversial.

Answer 82

The correct response is Option B. This patient has a split-nail deformity; the most appropriate management is full-thickness nail grafting from the toe. This deformity is caused by injury to the nail bed, leading to scarring of the bed. The nail plate does not grow in the scarred area, resulting in a split in the nail plate. The deformity described involves both the sterile and germinal matrices. Therefore, only a full-thickness nail will provide the sterile and germinal matrix components required for reconstruction. When a full-thickness nail bed graft is harvested, donor morbidity will always occur. Therefore, the donor site should be from the first or second toes or from spare parts in multidigit injuries. In patients who have a small scar affecting the sterile matrix only, appropriate management may include excision of the scar and reapproximation of the sterile matrix. This is usually not possible unless the affected area is quite narrow and there is no involvement of the germinal matrix. A split-thickness nail bed graft from either another finger nail bed or a toe will not provide the components needed for reconstruction of this defect. In addition, using another finger as a donor will result in an unsightly donor defect in the hand.

Answer 83

The correct response is Option B. The Moberg volar advancement flap is a useful and rugged flap for thumb tip coverage of open wounds up to a maximum of 2 cm. The principal advantage of the flap is that it provides like tissue with near-normal sensitivity. In one series of Moberg flaps, when patients with associated bony amputations were excluded, 6 of 11 patients were found to have extension deficits at the interphalangeal joint with a resultant reduction in active range of motion of at least 20 degrees. Unlike other flaps used for thumb coverage, like the Littler neurovascular island flap, sensory retraining is not necessary with the Moberg flap. Dorsal thumb skin necrosis is not a likely complication of the Moberg flap when used for thumb coverage, as the thumb has an independent and hardy dorsal circulation. This is in contradistinction to the other digits, where a volar advancement flap would likely result in dorsal skin necrosis because of inadequate dorsal circulation. Hook-nail deformity can occur after distal fingertip injuries with tissue loss; this would not likely be related to use of a Moberg flap, but instead to loss of support of the distal nail bed. Because the thumb neurovascular bundles are included in the volar tissue advancement of the Moberg flap, volar flap necrosis is an unlikely complication given the robust circulation of the flap.

Answer 84

The correct response is Option E. The most appropriate option for this patient is to perform a replantation with the use of vein grafts to the snuffbox for arterial inflow. Roping injuries are a combination of both an amputation as well as an avulsion, resulting in a significant zone of injury to all structures, but especially to the vessels, which sometimes have up to 4 cm of involvement with bruising of the intima and adventitia and separation of the media from the vessel walls. This zone of injury can result in anastomotic failure and digital demise if not recognized both by the mechanism of injury as well as careful examination of the structures under the operating microscope during attempted repair. Primary anastomosis in these particular injuries is most often not possible; therefore, the use of vein grafts after resection of the involved segment is an optimal strategy. The use of an end-to-side anastomosis into the radial artery at the snuffbox has been described with good success, and would be the preferred choice in this situation. A completion amputation of the thumb at this level (just distal to the metacarpophalangeal joint) would sacrifice needed thumb length and compromise ultimate function. As the thumb is reported to be responsible for up to 40% of hand function, this would represent a significant impact to the patient. It is difficult to repair the FPL tendon once avulsed from the musculotendinous junction, and many authors advocate for FPL resection rather than attempted repair. As the carpometacarpal joint of the thumb is intact, it will afford good range of motion of the thumb in all directions, even if the thumb serves merely as a “post” without ability to flex at the interphalangeal joint. Nonvascularized iliac crest bone grafting with a reverse radial forearm coverage is a surgical option but would not be the primary option in this acute amputation with an intact amputated part eligible for replantation, nor would it be preferred over staged toe-to-thumb transfer for better restoration of function and appearance. A toe-to-thumb transfer would be a good option in this patient if the thumb could not be replanted due to extensive distal injury, distal contamination, or loss of the digit during injury. In this particular case, none of those criteria are met.

Answer 85

The correct response is Option C. Although composite grafts will often survive in children and may be attempted in adults, aggressive defatting of the amputated segment and removal of bone fragments may still fail. The photograph demonstrates an eschar resulting from necrosis following reattachment of an amputated fingertip pulp. In the absence of underlying exposed ?white? structures such as joints, or tendon denuded of tenosynovium, optimal healing and function will occur via secondary intention. In this case, removal of any sloughing eschar will facilitate local wound care during healing. Skin grafting is useful for covering larger defects; however, sensation over the graft will be less satisfactory than over a fingertip wound that heals by secondary intention. A variety of local flaps have been used for fingertip tissue loss, including bilateral V-Y (Kutler) and volar advancement (Atasoy/Tranquilli-Leali) flaps. V-Y flaps place a scar directly in the midline of the pulp and are limited in the degree to which they may be advanced. The longer volar advancement flaps may be useful in covering bone or supporting the nail bed in the setting of a palmar oblique amputation through the distal phalanx; however, these flaps carry an increased risk of flexion contracture at the proximal interphalangeal (PIP) joint. Pulp necrosis can occur in the setting of digital ischemia due to Raynaud disease or thrombotic ulnar artery occlusion (hypothenar hammer syndrome). Periarterial sympathectomy can prevent tissue loss in some cases of vascular spasm or insufficiency. In this patient with an otherwise visibly well-perfused hand and discrete history of trauma, digital ischemia would be an unlikely cause of the necrosis.

Answer 86

The correct response is Option C. Except for Cleland ligament, any of the above named structures can become involved in Dupuytren contracture. Once involved in a contracture, the name of the structure is changed to include ?cord? (e.g., natatory ligament becomes natatory cord). A spiral cord is formed when Dupuytren disease affects the pretendinous band, spiral band, lateral digital sheet, and Grayson ligament. The normal palmar fascia structures pass around the neurovascular bundle in a spiral fashion. As the cord forms and contracts, it eventually becomes straight. The neurovascular bundle is then displaced centrally on the digit and is distorted to spiral around the cord.

Answer 87

The correct response is Option B. The thumb tip is an important structure for opposition and holding objects to the fingers. Thumb function depends on restoration of sensation and durable, reliable padding. When there is bone or tendon exposure, coverage with a flap is preferred. Small thumb tip defects (1 to 1.5 cm) can be reconstructed with a volar rectangular advancement flap, popularized by Moberg. Larger thumb tip defects require other flaps, such as the first dorsal metacarpal artery (FDMA) flap or the Little flap (dorsoulnar aspect of long finger). The FDMA flap can provide a larger wide flap than the Little flap and can be harvested with both venae comitantes and additional subcutaneous vein to provide more reliable venous drainage than the Little flap. Also, the FDMA flap donor site carries less risk of functional compromise of the donor finger than the Little flap donor site. The Little flap donor site can develop flexion contracture if the flap is harvested too volar over the finger, the interphalangeal creases are not preserved, and full-thickness skin grafting is not used on the donor. Both flaps are innervated and sensate and will require cortical reorientation, which can take approximately 1 year, more reliably for younger patients. Free toe pulp transfer would be excessive for this magnitude of injury. When no bone or tendon is exposed, the defect can be reconstructed with a skin graft if greater than 1 cm or allowed to heal spontaneously if less than 1 cm.

Answer 88

The correct response is Option D. Ligation of the radial artery is inappropriate because revascularization through collateral vessels will occur. Arteriovenous fistulas may be acquired during hospitalization secondary to continued intravenous access. Blood flows rapidly from the high-pressure artery to the low-pressure vein. Diagnosis of an established arteriovenous fistula is usually obvious secondary to the palpable thrill. Duplex imaging, technetium scanning, and magnetic resonance angiography are diagnostic. Arteriography is usually not necessary unless there is a question of the diagnosis or if the lesion is small enough to embolize. If surgery is selected, early exploration, excision of the fistula, and reconstruction of the artery are recommended. Vascular ablation would not be appropriate. This lesion does not represent a hemangioma and injection of a corticosteroid would be inappropriate. Observation would not be indicated because the lesion is reportedly growing and the overlying skin is becoming thin and potentially unstable.

Answer 89

The correct response is Option C. Local flap coverage is indicated when there is exposed bone or tendon. The flexor profundus tendon attaches to the base of the distal phalanx. Loss of the profundus tendon results in a significant loss of grip strength. Therefore, the profundus should be preserved if possible. Wounds on the fingertip that are smaller than 1 cm are allowed to heal by secondary intention, which provides better return of sensation and an even smaller scarred area. Larger areas, particularly those with an exposed distal phalanx, require coverage. Skin grafting may be indicated for large wounds that are not expected to heal in a reasonable amount of time. The profundus tendon should not be sutured to the extensor tendon, because this could result in a quadriga effect and a loss of grip strength.

Answer 90

The correct response is Option C. Hypothenar hammer syndrome occurs following repetitive blunt trauma to the hypothenar eminence. It is associated with cold intolerance, pain near the distal aspect of the Guyon canal, ulnar sensory dysfunction, and sometimes a mass near the hypothenar eminence. In severe cases, ulceration can occur in the ring and little fingers. The underlying pathology is thrombosis of the ulnar artery at the level of the Guyon canal. Surgical treatment of hypothenar hammer syndrome consists of excision of the thrombosed arterial segment, usually followed by vascular reconstruction with primary repair or construction of a vein graft. Fracture of the hook of the hamate, or hamulus, is seen more often in athletes who use rackets (ie, golfers, hockey players) or have direct trauma to the palm (ie, baseball catchers). An injury with acute pain is often noted, and tendon rupture may follow months later. Masses and fingertip ulceration are not seen with this condition. Treatment consists of excision of the fracture fragment. Ganglion cysts of the Guyon canal usually present with motor dysfunction, sensory dysfunction, or both. Cold intolerance, fingertip ulceration, and a mass are not usually found. Persistent median artery may present as a cause of carpal tunnel syndrome but would not cause a mass or ulceration. Systemic sclerosis is a relatively rare connective tissue disorder. Its hallmark is calcium deposits within the skin and progressive skin tightening. While skin ulcerations are found in systemic sclerosis, masses in the ulnar palm are not.

Answer 91

The correct response is Option D. The nail is supported by the dorsal tuft of the terminal phalanx. Following distal fingertip trauma, varying amounts of nail support may be lost, resulting in the nail curving palmarwards. This curvature is dependent on the degree of bony loss, the amount of remaining nail bed, and the degree of scar contracture at the hyponychial-pulp interface. The ?parrot beak,? or hook nail, deformity is caused most commonly by tight closure of a fingertip amputation and excessive palmar tension at the hyponychial-pulp suture line. The hook nail deformity is a relatively common complication following fingertip amputation. It can be corrected or prevented with a carefully performed surgical procedure. The nail plate is removed. The redundant nail bed that is folded over the tip of the terminal phalanx is carefully removed with an additional 2 mm that is supported by the terminal phalanx, which ensures that wound healing will not draw the nail bed over the tip of the phalanx again. The fingertip is then resurfaced by a V-Y advancement flap, with precautions taken to avoid all tension in the flap.

Answer 92

The correct response is Option E. The treatment of nail injuries can vary depending upon whether or not a nail plate injury is noted. When the nail plate is intact, the diagnosis of a nail bed injury is determined by the presence of a subungual hematoma. Subungual hematomas cause pressure in the closed space between the nail plate and nail bed, resulting frequently in throbbing pain. Hematoma drainage (trephination) is required for pain relief. This can be done with a battery-powered microcautery device or heated sterile paper clip. The hole should be large enough to allow for prolonged drainage. Care should be taken with the cautery device to avoid further injury to the nail bed. If the nail edges are disrupted or the nail plate is torn, the nail plate should be removed to explore and repair the nail bed. The torn nail plate can be removed to provide exposure for the repair. Lifting the nail plate can sometimes further injure the nail bed. Complete removal is not always mandatory. Extremity elevation will only alleviate the pain minimally. A digital block with epinephrine will provide temporary relief. Amputation is excessive treatment for a nail bed hematoma. Nail beds that are missing a sterile matrix can be reconstructed with a sterile matrix graft, often from the same injured nail bed (smaller defect) or the great toe (larger defect).

Answer 93

The correct response is Option E. Osteopenia is related to disuse and is typical in Stage II of complex regional pain syndrome (CRPS). Calcium stores need to be depleted by 30 to 50% for the osteopenia to become apparent, so this finding may appear more regularly in postmenopausal women. The demineralization affects both cortical and cancellous bone. The clinical presentation of CRPS is slightly different depending on the stage. In Stage I, there is extreme pain out of proportion to the injury, hyperesthesia, edema, erythema, and hyperhidrosis, all of which last for 3 months. Stage II is the ?dystrophic? phase and spans between the third and the ninth month. It is characterized by pain, pronounced stiffness, ?hard? edema, altered blood flow (increased warmth alternating with cyanosis), hair loss, decreased moisture, and osteopenia visible on plain x-ray study. Stage III starts at approximately the ninth month and lasts until 18 months after onset. It represents the ?atrophic? phase, which features increased stiffness and pale, cool, and dry skin, but decreased pain. Tendon adhesions and disruption of the tendon repair are not unique features of CRPS and occur regardless as complications of tendon repair surgery. Abnormalities in blood flow are common in CRPS, which is a direct effect of autonomic dysfunction, and occurs in 98% of cases. The vasomotor changes include loss of thermoregulatory and sudomotor control and manifest as a discolored limb (pale, red, or blue) with excessive sweating or anhidrosis. Numbness is not a typical feature, whereas hyperalgesia and allodynia are very prominent and extend beyond the anatomical confines of any particular peripheral nerve. Exception would be noted if the inciting injury were to involve the nerve.

Answer 94

The correct response is Option D. Injuries to the fingertip are among the most common injuries seen by the hand and plastic surgeons. These injuries can affect all components of the hand, including skin, bones, nerves, tendons, and vessels. In fingertip injuries without a bony amputation or with minimum exposed bone (less than 0.5 mm), a variety of reconstruction methods are possible. For preservation of sensation of the fingertip, the most appropriate method of reconstruction is healing by secondary intention with the use of moist dressings. Skin grafts, either full- or split-thickness, have the poorest sensory recovery. Flaps, either local or regional, provide decreased sensation in the reconstruction.

Answer 95

The correct response is Option C. Nail bed deformities are common after injury to the fingertip. The photograph shows that the patient has a synechia of the nail bed at the lateral aspect of the eponychial fold. In the scenario described, the problem is twofold. First, the eponychial fold is contracted and adherent to the underlying nail bed. Second, the nail bed itself is likely scarred. Therefore, dermabrasion and stent will not affect the status of the nail bed and will not improve the deformity. Reconstruction with a cross-finger flap and bone graft is good for a hook nail deformity but is not appropriate for scarred nail bed. Excision of the scar and attempt at advancement and primary closure is likely to fail in the scenario described as it is limited to defect of 1 mm or less. Given these constraints, resection of the scar and replacement with a graft from an adjacent finger or from one of the toes along with a flap procedure on the eponychial fold is most likely to correct the deformity. Full-thickness skin grafting will not affect this patient €™s goal of improved appearance.

Answer 96

The correct response is Option B. Multiple local flaps are available for coverage of finger defects. A reverse cross-finger flap is used to cover soft-tissue defects on the dorsum of an adjacent digit. The skin on the donor finger is incised on the side closest to the recipient finger and elevated off of the underlying dorsal subcutaneous tissue. The dorsal subcutaneous tissue of the donor finger is raised as a flap based on the side closest to the recipient finger. The flap is sutured to the recipient finger and is used as a bed to receive a full-thickness skin graft. The native skin is then returned to the dorsum of the middle phalanx of the donor finger. If the volar surface of a finger requires coverage, a standard (not reverse) cross-finger flap is used. The photograph shown on the left demonstrates the reverse cross-finger flap raised from the dorsum of the long finger and positioned over the index finger. After inset of the flap, the skin of the donor finger is closed primarily. A skin graft is applied over the flap on the dorsum of the recipient finger as shown in the photograph on the right.

Answer 97

The correct response is Option E. Toe-to-thumb transfer has become the standard of care for thumb reconstruction when the level of loss occurs at or around the metacarpophalangeal (MCP) joint. The functional outcomes from the transfer are excellent and the donor defect, while not completely free from morbidity, is acceptable. Wound and nerve complications, such as neuroma, can be successfully managed through traditional techniques. Revision amputation of the thumb in the patient described would be at or proximal to the MCP joint level. Even with web space deepening, there would be insufficient length of the thumb against which the other fingers could oppose. Distraction lengthening requires a higher-quality skin envelope than exists in the patient described to tolerate the increased space that would be occupied by the thumb metacarpal. In addition, the only remaining mobile joint in this patient would be the carpometacarpal (CMC) joint. Also, the distal end of a thumb created by this technique would have poor sensation and poor durability. Debridement and coverage with a radial forearm flap would provide high-quality tissue that could even be made sensate with coaptation of the medial and lateral antebrachial cutaneous nerves to the digital nerve stumps. However, there would still be inadequate length of the thumb with this method. Pollicization, while less commonly used in adult than in pediatric reconstruction, can still be useful when the level of amputation occurs at the CMC joint, or when the patient cannot tolerate or will not accept microsurgical transfer of a toe. Pollicization generally moves the index finger to the thumb position; pollicizing the long finger is technically very difficult to do because of the vascular pedicle. Given that the index finger is already lost in this patient, sacrifice of the long finger would leave only two mobile fingers on this hand. Photographs of the patient several months after great toe-to-thumb transfer are shown. Although the great toe is slightly larger than a normal thumb, recovery of function is quite good.

Answer 98

The correct response is Option D. The most appropriate management is revision amputation. For the patient described, the tendons, nerves, and vessels have been stretched and avulsed, which results in an extensive zone of injury. A well-planned amputation should be considered a reconstructive procedure and can return functional use of the hand to the patient. Goals include preservation of functional length, provision of durable coverage, preservation of sensibility, prevention of neuromas, prevention of joint contractures, minimal morbidity, early prosthetic fitting, and early return to activities of daily living. The surgeon should take into account the patient €™s occupation, functional status, and attitude toward the proposed amputation. In the scenario described involving a proximal phalanx amputation of the index finger in a manual laborer, the shortened finger will likely be bypassed in favor of the long finger for use in pinch. Amputation can result in a reliable and functional outcome and allow the patient to return to work quickly. Completion of the amputation can be performed, or ray amputation can be undertaken, to eliminate the intervening index finger segment and improve thumb pinch function. A groin flap can be used for soft-tissue coverage but requires the hand to be attached to the groin for a period of time. This can result in stiffness of the other digits and requires a staged procedure. A reverse radial forearm flap can be used for coverage of soft-tissue defects in the hand. This requires sacrifice of a major vessel to the hand and, in this case, would only preserve a section of bone that will serve little function. Microvascular replantation is a challenging prospect in the setting of a ring avulsion injury. Relative contraindications in the patient described would include the avulsion nature of the injury and presence of single-digit amputation within Zone 2. These factors lead to less successful outcome, and replantation would delay the return to work. Skin grafting is not likely to be successful in this patient, who has exposed bone. The lack of tendons would result in absence of movement, and the lack of nerves would lead to loss of sensibility.

Answer 99

The correct response is Option B. The set of symptoms in the patient described are consistent with scleroderma or systemic sclerosis. Findings in these patients include calcinosis, Raynaud phenomenon, esophageal dysphasia, sclerodactyly, and telangiectasia, or CREST syndrome. Those with overlap syndrome have associated findings characteristic of lupus, dermatomyositis, or rheumatoid arthritis. Therefore, CREST syndrome is the most likely diagnosis. A history of heavy smoking is more consistent with finger ulcers associated with thromboangiitis obliterans (Buerger disease); however, these patients do not have shiny skin, and their symptoms are generally limited to the hands and feet. A blow or repetitive vibration to the hand might suggest ulnar artery thrombosis and hypothenar hammer syndrome, which can also lead to fingertip ulceration, but these conditions are often limited to one hand and in most cases involve only the ring and little fingers. This syndrome is often seen in patients employed as manual laborers. Hyperthyroidism has nothing in common with the symptoms of the patient described. Finally, sickle cell anemia is characterized by severe pain in the long bones, abdomen, and face. Although hand pain with dactylitis and leg ulcers can be present, ulceration of the fingertips is not common.

Answer 100

The correct response is Option E. The thumb contributes roughly 40% to hand function, and the fingers contribute 60% to hand function. Therefore, amputation of the thumb decreases hand function up to 40%, making reconstruction a high priority. Pollicization refers to the neurovascular pedicle movement of a finger, often with its metacarpal, for thumb reconstruction. Pollicization can be used for amputations of the thumb between the middle of the first metacarpal and at the carpometacarpal joint, but it works best for amputation at the level of the carpometacarpal joint. If the index finger is injured and has little mobility, the injured index finger should be used for thumb reconstruction and serve as a stable post. If thenar muscles are intact, opposition can be expected. Benefits of index finger transfer include aesthetic results, potential motion of transferred and retained joints, and provision of reliable sensation. Debridement and closure of wounds is not ideal, as this would impair function of the dominant hand. Great toe-to-thumb microsurgical reconstruction is best for amputations between the metacarpophalangeal (MCP) joint and interphalangeal joints but can be used for amputations proximal to the MCP. In the patient described, the traumatized index finger serves as an excellent alternative for reconstruction of the amputated thumb with preservation of a normal foot. Osteoplastic thumb reconstruction is rarely performed today, as it results in a stiff, broad, floppy thumb with limited sensation. It involves the combination of a bone graft and flap to lengthen the thumb. At least three stages are required: bone graft from iliac crest covered in a tubed distant flap; flap pedicle division; and transfer of the neurovascular sensory flap from the long finger to the thumb €™s pinch contact surface. If the amputated part had been mangled, lost, or inappropriately preserved, then replantation would not have been an option.

Answer 101

The correct response is Option C. The extensor tendons and flexor tendons in the scenario described have been avulsed from the musculotendinous junction. In addition, the nerve ends extend proximally beyond the level of the soft-tissue injury; both of these findings are indicative of an avulsion-type injury. Such injury mechanisms often result in significant intimal injury within digital arteries, limiting the success of replantation. The amputated part was appropriately managed, and warm ischemia time was minimized. Digits have been successfully replanted with greater than 24 hours of cold ischemia time. Amputations at the metacarpophalangeal or interphalangeal level of the thumb may result in joint fusion; however, in this scenario, bone stock is adequate for skeletal fixation. Infection is a potential problem following any traumatic hand injury, but adequate surgical debridement and appropriate antibiotic coverage make replantation loss from infection a rare occurrence.

Answer 102

The correct response is Option E. Ring avulsion injury remains one of the most challenging replantation problems because of the large zone of injury of the soft tissues. As a result, the regional vessels are significantly damaged due to the stretch avulsion, and as such, need to be resected widely and replaced with vein grafts. Amputated parts should be transported dry in a saline-iced slurry and protected by a plastic bag. Bone grafting should be reserved for a failed union, in the subacute or late setting, while tendon repair should be performed at the time of replantation. A neural repair with more than four sutures is not necessary and may contribute to neuroma formation.

Answer 103

The correct response is Option B. The tissue requirements are determined by the nature of the wound bed and functional requirements for the site of reconstruction. Skin grafts are inappropriate in the face of exposed tendon or tendon sheath. Advancement of the volar tissue of the thumb is useful for distal thumb defects. Dissection of the skin, subcutaneous tissue, and neurovascular bundles from the underlying tissue and flexion of the interphalangeal joint allow for distal movement of the tissue for thumb pulp pad coverage. This approach would not be useful for a volar defect at the level of the proximal phalanx. The first dorsal metacarpal artery flap could be used to provide coverage of this area of the thumb. The skin and subcutaneous tissue can be elevated from the dorsum of the index finger to the level of the middle phalanx. The first dorsal metacarpal artery is included with this tissue. If a sensory flap is desired, branches of the radial nerve within the flap can be preserved or coapted to sensory nerves at the recipient site. A thenar flap would be appropriate for providing coverage for fingertips but not this region of the thumb.

Answer 104

The correct response is Option B. Functional outcomes following replantation vary with the level of injury. Replantation of single digits amputated within the zone II level is relatively contraindicated due to postoperative stiffness. It is also contraindicated when rehabilitation will significantly delay the patient €™s return to work and the procedure offers minimal or no functional benefit. Replantation of single digits, particularly index fingers, usually does not improve hand function. Replantation should be considered on nearly all parts in healthy children. Replantation should be considered in most cases of thumb amputation.

Answer 105

The correct response is Option B. The patient described has a high-pressure injection injury to the index finger of his assisting hand. As with electrical injuries, the damage caused by the destructive chemicals in paint and other hydrocarbons as well as caustic cleaning solutions far exceeds the usual small and apparently innocent entrance wounds. The chemicals tend to travel down the finger and can involve the tendon sheaths with migration to the wrist, resulting in increased morbidity. The subcutaneous tissue is destroyed by either saponification or dissolution of the lipids. This situation warrants early aggressive surgical therapy. Outcome for delayed treatment is nearly uniformly poor, resulting in either amputation or permanent stiffness. The best outcomes result from emergent debridement of all involved tissue and open dressing changes. Early mobilization will assist in treatment. Given these facts, observation for this patient is inappropriate. As his finger remains perfused and sensate, there is no need for immediate amputation. Immediate amputation is appropriate for patients who present with cool, insensate fingers. Delayed amputation may be required for finger necrosis. Mineral oil is itself a hydrocarbon and potentially toxic and therefore not appropriate for the clinical scenario described. The outcome for less caustic injection injury, such as water or air, is more favorable and therefore warrants less aggressive therapy. These patients can be treated with administration of antibiotics, elevation, and early mobilization with minimal or no debridement. Because the patient described had oil-based paint injected into his finger, the less aggressive therapy is not appropriate.

Answer 106

The correct response is Option E. A number of options exist for the management of soft-tissue loss from the volar aspect of the fingertip. Healing by second intention can provide a durable fingertip with acceptable sensation. Unfortunately, when there is significant soft-tissue loss, there may be insufficient padding for the fingertip. The goal of intervention is to improve the bulk of the soft tissue with sensate tissue if possible. The toe pulp flap provides the best opportunity to accomplish both of these goals. The flap is harvested from the lateral aspect of the first toe or the medial aspect of the second toe. The vascular supply of the flap is the first dorsal metatarsal artery and branches of the saphenous venous system. The flap is innervated by the deep peroneal nerve and the palmar digital nerves of the toe. These nerves can be coapted to nerves of the recipient finger. Two-point discrimination of less than 10 mm can be obtained. Thenar and groin flaps involve staged transfer of soft tissue to the recipient digit. These flaps supply the desired soft-tissue bulk; however, they do not provide sensation to the transferred tissue. A cross-finger flap would supply a small amount of additional soft-tissue bulk. The flap is innervated through coaptation of dorsal digital nerves of the donor site to recipient digital nerves. Neither the sensation nor the amount of soft-tissue bulk would match that provided by the toe pulp flap. The Kutler flap entails advancement of tissue from the sides of the finger over the tip in V to Y fashion. Sensation and vascularity are maintained for this tissue. The amount of tissue that this technique provides would be modest compared to the other approaches.

Answer 107

The correct response is Option E. Nail bed injuries are common occurrences. Knowledge of nail bed anatomy is essential for proper evaluation and treatment. The germinal matrix is the most proximal part of the nail bed and is hidden from view by the eponychium. The germinal matrix produces 90% of the nail plate and extends to the visible white arc of the nail known as the lunula. The sterile matrix is the distal portion of the nail bed and adds a thin layer of cells to the undersurface of the nail, which maintains nail adherence to the nail bed. In the patient described, the sterile matrix is scarred and the nail cannot adhere to the nail bed. Reconstruction requires removal of the scarring to the sterile matrix followed by split-thickness nail bed grafting. Though harvesting of a split-thickness nail bed graft should not leave any deformity, one study found a 25% donor deformity. In contrast to a sterile matrix defect, when using a nail bed graft for reconstruction of the germinal matrix, a full-thickness graft is needed. Also, when harvesting a full-thickness nail bed graft, donor morbidity will always occur. Therefore the donor site should be from the first or second toes or from spare parts in multidigit injuries. Lateral Kutler flaps, which are used for soft-tissue loss of the fingertip, may be required in conjunction with nail bed reconstruction but not in this scenario. A full-thickness graft is not an appropriate choice because it is not necessary, and an uninjured digit should not be used for a full-thickness graft donor site. Lateral paronychial-releasing incisions with central advancement flap can be used for full-thickness germinal and sterile matrix losses up to around 4 mm, but this defect is too extensive. Release of the sterile matrix scar and acellular regenerative dermal matrix grafting are more appropriate for a pincer nail deformity.

Answer 108

The correct response is Option B. The first dorsal interosseous is in the zone of injury. When amputations occur through the distal aspect of the palm, the intrinsic muscles are usually injured and intrinsic function is poor despite successful replantation. Finger abduction and adduction, metacarpophalangeal joint flexion, and proximal and distal interphalangeal joint extension and key pinch are limited as a result. Debridement of injured muscle is recommended to prevent contracture and intrinsic tightness. In this setting, movement is generated by extrinsic muscle groups without the fine-tuning of motion usually provided by the intrinsic muscles. With sharp lacerations at the level of the distal palm, the flexor digitorum profundus and superficialis and extensor digitorum communis tendons typically function well with good repair technique, appropriate rehabilitation, and occasional secondary surgery. The flexor pollicis brevis is proximal to the zone of injury. The mechanism of injury is an important determinant in the outcome of the repair. Sharp injuries have the most discrete area of damage and therefore tend to have greater recovery of function. Blunt and avulsion €‘type mechanisms, which have greater zones of injury, require more extensive reconstruction and are associated with less complete restoration of function, including motion and sensibility. In addition to functional considerations, replantation of the amputated hand serves the patient by restoring the appearance of the hand.

Answer 109

The correct response is Option A. A durable, sensate, well €‘vascularized reconstruction is required. The most appropriate flap for reconstruction of the defect in the scenario described is the first dorsal metacarpal artery. When paired with the first dorsal metacarpal nerve, this flap provides sensate coverage of large defects to the distal volar aspect of the thumb. Photographs are shown below. The Moberg flap is a sensate advancement flap used to reconstruct volar thumb tip defects of up to 1 cm. This defect is too large. Use of this flap would endanger the blood flow for the replanted thumb, and it would have a high likelihood of partial flap loss. The reverse posterior interosseous artery flap is a pedicled fasciocutaneous flap often used to reconstruct the dorsum of the hand or the first web space. A proximal extension would be required for the flap to reach the distal volar aspect of the thumb. Tip necrosis is a known complication of this nonsensate flap. The reverse radial artery flap is often a fine choice for thumb reconstruction. In the scenario described, however, ligating the radial artery proximal to the harvested flap may compromise the vascular supply to the replanted thumb. The replanted thumb has already displayed signs of potential vascular compromise caused by the loss of the thumb tip after replantation. The thenar flap is a random flap used to cover volar tip defects of the long and ring fingers. The defect in the patient described could not be covered with a thenar flap.

Answer 110

The correct response is Option B. Treatment of the PIP joint flexion contracture in Dupuytren disease can be difficult and often unsatisfying because early (within one to three years) partial recurrence is common. Adding to this frustration is the failure of recurrent PIP joint disease to respond to therapy and splinting as effectively as MCP joint recurrences. Primary treatment of PIP joint Dupuytren contractures often results in incomplete correction; this also stands in contrast to the complete correction typically obtained at the MCP joint. Recurrent PIP joint disease may require more aggressive management, including more extensive joint release (accessory collateral ligaments, palmar plate/check rein ligaments, flexor sheath) and possible dermatofasciectomy with full thickness skin graft reconstruction. Outcomes from reoperation are guarded, and arthrodesis of the PIP joint as a salvage procedure may be warranted. Routine release of the volar/palmar plate has not been shown to improve outcomes for primary correction of PIP joint contractures in Dupuytren disease.

Answer 111

The correct response is Option C. An amputated thumb is an indication for replantation in the hands of an experienced microsurgeon with the appropriate team regardless of the level of injury to the thumb. In the scenario described, the thumb is well preserved and the cut is clean with no avulsion injury. Attempts should be made to preserve the length and function of the thumb with replantation. Immediate pollicization of the great toe is not indicated in the scenario described, where the distal amputated thumb is well preserved and available for replantation. If the amputated part had been mangled, lost, or inappropriately preserved, thumb reconstruction with great toe transfer could be offered as a reconstructive option. The importance of the thumb in hand function precludes any further amputation of the thumb. Although the thumb wound would likely close by secondary intention if there is no exposed bone, it is best to preserve as much length as possible, making replantation the operation of choice for the thumb. If the part is not replantable, the volar advancement flap, or Moberg flap, is indicated for preservation of length and soft-tissue coverage of exposed bone. A split-thickness skin graft could potentially also be used for coverage but would require shortening of the exposed bone and would not provide the sensibility that is helpful in the use of the thumb. Reconstruction of the thumb does not offer restoration of length and is not appropriate in this clinical situation.

Answer 112

The correct response is Option C. Transplantation of the ipsilateral great toe to the thumb would provide the best function for the patient described. With the degree of shortening that occurs with the level of amputation described, lengthening of the thumb is an important component of reconstruction. This reconstruction can be accomplished with transplantation of the first or second toe, distraction lengthening of residual bone or osteoplastic reconstruction using a flap for soft-tissue coverage, and vascularized or nonvascularized bone autograft. The ipsilateral great toe provides the most complementary anatomy when transplanted to the thumb. Toe transplantation can be performed at the time of injury or in a delayed fashion. Although pollicization of the index finger can be performed in adults, it is typically reserved for amputation from the level of the carpometacarpal joint to the middle of the metacarpal. The functional outcome and aesthetics are inferior to those of great toe transplantation to the residual portion of the thumb. Incomplete conversion of position sense following pollicization is more common in adults than in children. For amputations through the middle to distal aspect of the proximal phalanx, widening of the first web space with Z-plasty and other local flaps or regional flaps, such as reverse radial forearm or posterior interosseous artery flaps, may provide sufficient length and motion for good function.

Answer 113

The correct response is Option E. Contraindications to replantation of hand and digits include the following: 1. Upper extremity time in the proximal to mid forearm with ischemia time greater than six hours 2. Concomitant life €‘threatening injuries 3. Multiple level injury 4. Severe crush or avulsion injury 5. Extreme contamination 6. Systemic illness or surgical history precluding replantation 7. Self €‘mutilation cases and psychotic patients The patient described has a mutilating hand injury with severe, multiple-level, crush amputation to the thumb and index finger rendering them unsuitable for replantation. Heterotopic replantation or transpositional microsurgery is the replantation of a digit in a nonanatomic location when the native digit is unsuitable or unavailable for replantation. There is no definitive rule for heterotopic replantation in cases of mutilating hand injury. The restoration of prehensile function is the primary goal in reconstruction following mutilating hand injuries. The thumb accounts for 40% to 50% of hand function. Other goals include establishment of at least two digits for tripod pinch, functional web spaces, wrist stability, transverse and longitudinal arches of the hand, and aesthetically pleasing appearance. Amputated digits may be replanted at the thumb position to provide restoration of prehensile function. Although establishment of index and middle fingers may be more aesthetically appealing, the use of the long and ring finger and the intervening longer web space will aid in tripod pinch. Priorities in hand reconstruction with heterotopic replantation following mutilating hand injury should be individually tailored to the clinical situation. Digits may be replanted €œdigit by digit € or €œpart by part. € €œDigit by digit € refers to complete replantation of one digit at a time. A €œdigit-by-digit € repair is suitable in cases where the amputated digits have differing warm ischemia times and the digit in the best condition is replanted first in a salvage effort. €œPart by part € refers to grouping the repair of a similar part for all amputated digits. Although the exact order of replantation is controversial, it typically starts with skeletal fixation before soft-tissue repair. The order is typically flexor tendons, extensor tendons, arteries, and veins. Arteries are typically repaired first, because venous efflux allows identification of veins for anastomosis. Some authors advocate venous repair first in guillotine amputations to reduce venous stasis and operative time from blood in the operating field. A €œpart-by-part € approach is generally used when the amputated digits all have the same degree of ischemia. Closure of the amputated stumps would not make use of the other digits for replantation. Although restoration of pinch is important, replantation of the severely crushed thumb and index fingers in any order would be inappropriate and would not likely survive. Replantation of the long, ring, and small fingers alone would leave the patient without a working thumb and pinch grip.

Answer 114

The correct response is Option C. Pincer-nail syndrome has been described as constriction in the distal portion of the shape of the nails such that there is an excessive transverse curvature of the nail plate that increases from the proximal to distal, resulting in constant severe pain. The etiology of the deformity has since been attributed to many factors including psoriasis, ill-fitting shoes, developmental anomalies, Î²-blocking agents such as practolol, allergic reaction, underlying epidermoid cyst, subungual exostosis, and osteoarthritis. Several authors have used dermal and collagen matrix grafts for correction. This surgery corrects the deformity by grafting soft-tissue collagen under the nail matrix, reelevating the edges. Coverage with a cross-finger flap is not thought to be necessary for the correction of this deformity but may be useful in other nail bed deformities such as hook-nail. Sympathectomy probably would not help as this is not an ischemic etiology. Various treatments for nail ablation either with chemical or electrocautery have been described. These treatments relieve the pain but result in permanent loss of nail aesthetics and function. Serial compression splinting is occasionally used for ingrown toenails but is not described for use in pincer deformity.

Answer 115

The correct response is Option A. Small, dorsal defects of the fingers can be reconstructed via a number of local flaps; as in many other parts of the body, adipofascial turnover flaps have been developed for the upper extremity, hand, and fingers. Advantages of these flaps include almost limitless donor sites, single stage reconstruction, and minimal donor site morbidity. For coverage of dorsal digital defects, adipofascial turnover flaps are designed with the base of the flap proximal to the defect. The flap itself is designed to be 2 to 4 mm wider than the skin defect with a base €‘to €‘length ratio of 1:1.5 to 1:3. A longitudinal incision over the center of the flap allows dissection of the flap from the overlying skin. The adipofascial flap is then elevated from proximal to distal from the underlying paratenon. Elevation stops approximately 0.5 to 1 cm proximal to the defect to create the base of the flap; the flap is then turned over into the digital defect and covered with a split €‘thickness skin graft (see the figure below). Given the damage to the adjacent long finger, a cross €‘finger flap would not be possible. A transposition flap from the dorsal thumb may suffice for first web resurfacing but will not adequately reach the dorsal index finger. Both the posterior interosseous artery and radial-artery based flaps are capable of resurfacing sizable defects on the hand and fingers; however, the added morbidity of harvesting these flaps does not warrant their use when a more suitable local flap is available. Image intentionally omitted

Answer 116

The correct response is Option D. Complications of Dupuytren disease have been reported to be 17% overall. Nerve injuries can be a devastating complication after surgery for Dupuytren disease. The digital nerves are displaced medially by the spiral cord, making them more prone to injury. Fortunately, nerve transection is relatively rare, reported in only 1.5% of patients with Dupuytren disease. Complex regional pain syndrome (reflex sympathetic dystrophy) may occur after Dupuytren disease, but this is an uncommon complication (approximately 4% to 8%). It can be confused with flare reaction, which can intense vasodilation; however, there is no associated pain. Infection in patients with Dupuytren disease is not significantly greater than other similar surgeries. Arterial injuries occur in less than 1% of Dupuytren cases. Recurrence after Dupuytren is significant; a recent study placed recurrence at 18% to 24%. Other studies, with 10 €‘year follow-up, have noted that no patients were free of disease. Patients should have realistic expectations on the possible complications and recurrence risks prior to surgery.

Answer 117

The correct response is Option B. If the area of loss of sterile matrix is significant, grafting with sterile matrix provides the best outcome. More than half of the sterile matrix is missing from the injured nail bed of the patient described, which is not enough to provide for coverage of the defect. Therefore, use of sterile matrix from the great toe as the donor site is the most appropriate intervention in the scenario described. Regenerative dermal matrix is not sterile matrix and application of it would not reconstruct either the germinal or sterile matrix. Allowing the nail bed injury of the patient described to heal by secondary intention would result in nail nonadherence and risk bony infection. The sterile matrix should not be reconstructed with a standard skin graft because this would also result in nail nonadherence and risk frequent infection.

Answer 118

The correct response is Option B. History of renal failure or kidney transplantation is associated with the highest risk of amputation in diabetic patients with hand infections. Amputation rates in this population range from 75% to 100%. Multiple studies have shown that diabetes mellitus negatively impacts the prognosis of hand infections. Hand infections in patients with diabetes take longer to resolve and are more likely to require multiple debridements than infections in patients without diabetes. In addition, initiation of treatment is more likely to be delayed in patients with diabetes. In 50% of cases, the initial surgical procedure does not control the infection adequately. Amputation rates for hand infections in patients with diabetes range from 7% to 63%. In up to 28% of patients undergoing amputation, a repeat procedure at a more proximal level is required. Insulin dependence, history of poorly controlled diabetes (as indicated by elevated hemoglobin A1c), white blood cell count greater than 14,000/mm3, and serum glucose level greater than 450 mg/dL have not been shown to significantly increase the risk of amputation in diabetic patients with hand infections.

Answer 119

The correct response is Option B. Scleroderma is an autoimmune disease that includes a disorder of the connective tissue and small blood vessels. This disease can affect the skin, hands, gastrointestinal tract, heart, lungs, and kidneys. The sclerosis or fibrosis is commonly seen in the skin of the face and perioral area. This sclerosis of the face gives the patient a mask-type appearance characteristic of scleroderma. The CREST symptom complex has been used to describe the most common findings of systemic sclerosis: calcinosis, Raynaud phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia. Ulceration at the fingertips is a common finding secondary to poor circulation. Skin breakdown can also occur at the proximal interphalangeal (PIP) and metacarpophalangeal (MP) joints caused by bony joint deformities as well as poor circulation. Tip ulcerations are common because of the poor circulation associated with scleroderma. Many of these ulcerations will successfully heal over time without surgery. An initial conservative approach should therefore be taken. This approach includes conservative debridement, topical antibiotics (eg, silver sulfadiazine), and limited resection of exposed bone. If active infection is present, antibiotics should be administered. If ulceration and pain fail to respond to conservative treatment, more aggressive intervention is required, including amputation and possible digital sympathectomy. Unfortunately, many patients who undergo digital sympathectomy continue to have pain and suffer recurrent ulceration. Calcinosis is the deposition of calcium within the dermis or subcutaneously. These deposits can cause pain, spontaneously cause skin breakdown, and drain calcific material. Symptomatic lesions require excision or partial removal to alleviate symptoms. Amputation, digital sympathectomy, and resection of the distal phalanx with secondary healing are not appropriate because conservative therapy should be attempted first.

Answer 120

The correct response is Option A. The condition of the patient described requires amputation of the entire distal phalanx. Chronic paronychia is usually caused by a candidal infection. Failure of medical treatment with antifungals requires culture, radiographic evaluation to exclude bony involvement, and biopsy to exclude malignancy, particularly squamous cell carcinoma. Squamous cell carcinoma is the most common primary malignancy of the hand. Lesions not involving the nail bed require excision with 1-cm margins; 2-mm margins are inadequate for squamous cell carcinoma. Tumors involving the nail bed or bone necessitate amputation of the entire distal phalanx. Ray amputation of the thumb results in excessive functional loss of the extremity and does not improve long-term survival.

Answer 121

The correct response is Option B. Because the extensor pollicis longus (EPL) and flexor pollicis longus (FPL) tendons are avulsed, repair or reconstruction of their function is difficult. When these tendons are reinserted, there is a risk of infection. The main contribution of the thumb to overall hand function is through its length and ability to oppose the fingers to grab and hold objects. The critical length of the thumb is the level of the interphalangeal (IP) joint. It is optimal to preserve the length of the thumb to at least the IP level. Thumb length is more important than motion. Considerable motion can be preserved through the metacarpophalangeal and carpometacarpal joints of the thumb. Therefore, thumb function is not significantly altered with fusion of the IP joint. Furthermore, fusion of the IP joint can allow for less tension across the microneurovascular repairs. This has been shown to improve survival rates for thumb replantations as well as produce reliable recovery of two €‘point discrimination through nerve repairs that are not under tension. Furthermore, shortening of the thumb allows for avoidance of the potential need for grafts to repair the artery or nerves. If the IP joint of the thumb is fused, there is no need to repair the FPL tendon. Revision amputation with closure, pollicization, or toe transfer would not yield the functional outcome of a successful replantation. Specifically, transfer of the great toe is not needed if thumb length is at the IP level.

Answer 122

The correct response is Option B. The Moberg flap is the most effective intervention for thumb tip defects of 1.5 cm or smaller. Some of the tactics that have been described to facilitate distal advancement of the flap include flexion of the thumb interphalangeal crease, extension of the lateral incisions proximal to the metaphalangeal crease, and islandization of the flap by releasing the skin at the base of the flap and skin grafting the donor wound. The cross-finger flap can be used for the thumb but is best suited for fingers of younger patients because of the risk of flexion contractures when used in older patients. Secondary healing is inappropriate in the case described because of the large size of the wound. Skin grafting is not appropriate for the patient described because bone is exposed. The thenar flap is harvested from the thumb and, therefore, is not used to reconstruct the thumb.

Answer 123

The correct response is Option A. In the small finger, the ulnar cord typically originates from the musculotendinous junction of the abductor digiti minimi. From this location, the pretendinous band, spiral band, lateral digital sheath, and Grayson ligament can become involved, which can result in significant contractures at the metacarpophalangeal and proximal interphalangeal joints. The other structures listed are not typically involved in Dupuytren contracture. The abductor pollicis brevis is the most radial thenar muscle and does not affect the ulnar cord. The antebrachial fascia is the superficial forearm fascia and is not related to Dupuytren contracture. The contractile cords involve Grayson ligaments and not Cleland ligaments. The Cleland ligament is dorsal to the neurovascular bundle. The volar carpal ligament covers the Guyon canal.

Answer 124

The correct response is Option E. The time interval between amputation and replantation can change a replantable situation to an unreplantable one. There are no strict guidelines for ischemia times. There have been case reports of a successful hand replantation performed after 54 hours of cold ischemia and a successful digit replantation after 42 hours of warm ischemia. Acceptable ischemia time is dependent on the amount of muscle in the amputated part: the more muscle, the shorter the acceptable ischemia time. General guidelines are that if warm ischemia time is greater than 6 hours for amputations proximal to the carpus or 12 hours for the digits, replantation is usually not recommended. Cold ischemia can double these acceptable time limitations. The patient discussed is a young police officer with an amputation of the thumb and index finger. The thumb is the only opposable digit and, as such, is critical for hand function. Thumb amputation is a strong indication for replantation. The dangerous weather in the scenario described precludes quick transfer; however, the cold ischemia time would be approximately 24 hours in a digit with no muscle. This time frame is within the limits for a successful outcome. Therefore, the most appropriate management in the scenario described is to wrap the amputated parts in saline-soaked gauze and place them on ice. Debriding and closing the wounds is not appropriate because this would treat the cold ischemia time as a contraindication for replantation and commit this patient to late reconstruction. Reattaching the amputated parts with sutures as a composite graft and applying splints to the involved digits is not appropriate because of the size of the amputated digit. Small composite grafts can survive; however, this applies to young children with distal tip amputations. Furthermore, suturing the parts back on will create a condition of warm ischemia instead of cold ischemia. In situations of near-complete amputations, the attached digits can be placed in an ice saline slurry. Dermabrading the epidermis of the amputated parts and inserting them under the skin of the abdomen through two separate incisions will not work for similar reasons. Replanting the amputated parts with step-by-step guidance of the plastic surgeon via telephone is inappropriate because of the poor outcome associated with an inexperienced operator.

Answer 125

The correct response is Option B. This defect is too large for reconstruction with a Moberg flap. Typically, the Moberg flap is suitable for 1- to 1.5-cm defects. A skin graft would be inappropriate because bone is exposed along the wound. Because the index finger is burned, the first dorsal metacarpal artery flap, which would usually be the first choice for this type of defect, is not available. The groin flap would be insensate and unstable and, therefore, is a poor option for reconstruction of the thumb. In the thumb, sensory restoration is crucial for hand function; therefore, an innervated flap is preferred. The gold standard neurosensory flap is the first web space flap. The first web space flap is harvested from the lateral aspect of the great toe and the medial aspect of the second toe. The general dimensions of the flap are 6 cm transversely and 3 cm longitudinally. This flap usually is based on the first dorsal metatarsal artery, which is a branch of the dorsalis pedis artery. It also can be based on the first plantar metatarsal artery, but the dorsal branch usually is used because of difficulty with exposure of the first plantar metatarsal artery. If more pedicle length is required, the arterial dissection can be extended to include the dorsalis pedis artery. The venous drainage of the first web space flap is reliable because either or both the venae comitante and the saphenous system can be used. Usually, the flap is harvested with the saphenous vein system because of its large caliber and easier dissection. There are several advantages to the use of the first web space flap for sensory restoration of the hand. The first web space flap provides a sensate glabrous surface similar to sensate glabrous defects of the hand. The flap has a relatively constant vascular and neural anatomy. The donor site usually can be covered with a split-thickness skin graft with minimal donor morbidity and minimal disturbance of foot mechanics. Studies have demonstrated a recovery of two-point discrimination of 3 to 8 mm with this flap for the thumb.

Answer 126

The correct response is Option D. The most appropriate method of replantation in this case is part by part; bone, flexor tendons, extensor tendons, nerves, arteries, veins. This patient has acute amputations and has presented promptly to the emergency department. In addition, all amputated parts have been approximately equally well preserved. In this scenario, the longer ischemia times tolerated by digital amputations allow for increased operative efficiencies by group repair of similar parts. Because all three digits have been equally preserved, replantation should proceed by group repair of similar parts. Therefore, the digit-by-digit options are incorrect. If the digits were in different states of preservation, with one or more digits being more mutilated than the others, then replantation would proceed digit by digit. In that scenario, the digit in the best condition would be replanted first and might be orthotopically replanted based on the clinical circumstance. In this particular instance, if the index digit were the only well preserved digit, then consideration would be given to replanting that digit in the ring position because ulnar-sided hand function is more important than index function radially. Skeletal stability must always be restored before any soft-tissue repairs. This is usually performed with crossed K-wires. Therefore, replantation part by part &Mac255; flexor tendons, extensor tendons, bone, arteries, veins, nerves is incorrect. The exact sequence of part-by-part repair thereafter is somewhat controversial; however, the heavier structures (flexor and extensor tendons) should be repaired first, followed by microsurgery. Arterial repair usually precedes venous repair, because the venous efflux assists with identification of the most desirable veins for anastomosis or grafting. The timing of the repairs often depends on tourniquet time but may be done either before the arterial repairs or after the venous repairs.

Answer 127

The correct response is Option A. Goals in management of fingertip amputations include wound closure, maximizing sensory return, maintaining joint function, obtaining satisfactory cosmesis, and preservation of length, especially in the thumb. Split-thickness grafting would not be appropriate to cover with exposed bone. The cross-finger flap is a pedicled, heterodigital flap that brings in durable cover from the dorsal middle phalanx skin from an adjacent finger. The donor site requires a split-thickness skin graft for coverage. The thenar flap is a regional pedicled flap based on the soft tissue of the thenar eminence. Both the cross-finger flap and the thenar flap reconstructions have the disadvantages of requiring a second stage for division and inset as well as problems with joint stiffness secondary to immobilization while awaiting vascular ingrowth from the recipient bed. The Atasoy-Kleinert flap is a homodigital V-Y advancement flap of the volar pulp tissue useful in transverse or oblique fingertip injuries with greater soft tissue on the volar aspect. The Atasoy-Kleinert flap is the best choice because it is a one-stage repair that allows primary closure of its donor site. The Moberg flap is a volar advancement flap used in thumb tip amputation coverage.

Answer 128

The correct response is Option D. This patient has a Dupuytren’s contracture of the hand. Dupuytren’s disease is a benign fibroproliferative disorder of the palmar fascia that may result in disabling finger contractures. This condition has been associated with epilepsy, alcoholism, chronic pulmonary disease, diabetes, and northern European ancestry. There is no cause-and-effect relationship between the existence of one of the comorbidities listed above and the development of Dupuytren’s disease. Because the risk of complications with this disease is significant, there are narrow indications that must be met to justify surgery for this condition. The surgery involves direct excision of the involved fascia. This can be performed through zig-zag (Brunner), midlateral, Y-to-V incisions, and longitudinal with zig-zag rearrangement incisions. The complications of Dupuytren’s fasciectomy include recurrence, hematoma, skin loss, infection, nerve and arterial division, loss of flexion, reflex sympathetic dystrophy, and digital loss. Threshold indications concerning contractures are 30 degrees at the metacarpophalangeal (MP) joint and any at the interphalangeal (IP) joints, specifically the proximal interphalangeal (PIP) joint. Some studies have shown that when surgery was performed for patients with less than 30-degree MP joint contracture, surgery outcome was worse for some patients after fasciectomy. PIP joint contracture is not improved with joint release. Additionally, with or without PIP joint release, long-term improved motion is approximately 37% of the short-term improved motion. The general indications for Dupuytren’s fasciectomy include loss of 30 degrees of MP joint extension, any loss of proximal phalangeal joint extension, and neurovascular compromise. Spiral cords can wrap around the neurovascular bundles and cause neurovascular compromise. Solitary asymptomatic palmar nodules are observed. Tender nodules can be injected with corticosteroids or collagenase. Pain in the hand is not an indication for Dupuytren’s surgery. The most commonly involved finger is the ring finger. The anatomic structures that are involved with Dupuytren’s include pretendinous bands, spiral bands, lateral digital sheet, Grayson’s ligament lateral digital sheet, and natatory ligament. The superficial transverse ligament, deep transverse ligaments, Cleland’s ligament, and Landsmeer’s ligament usually are not involved.

Answer 129

The correct response is Option A. Palmar bands in an older man of Northern European descent without a history of trauma is most likely Dupuytren’s disease. Because the patient is entirely functional and has a history of slow progression, observation would be the best course of management at this time. Threshold indications for surgery include a 30-degree contracture of the metacarpophalangeal joint or any contracture of the proximal interphalangeal joint. In a fully functioning patient with slow progression of disease, immediate surgery would not be necessary. Corticosteroid injections are useful for painful Dupuytren=s nodules but are generally ineffective for the extensive bands described. Finally, although therapy is a routine part of the postoperative management of this problem, it is unlikely to be of benefit in preventing the progression of disease. Stretching the joint contractures with splints and external fixators has shown limited long-term improvement.

Answer 130

The correct response is Option B. In general, isolated amputations proximal to the flexor digitorum superficialis (FDS) insertion should not be replanted because of poor long-term function. Often these fingers are bypassed by the other uninjured digits and are perceived by the patient as a nuisance. Certain situations warrant attempts at single finger replantation, such as in musicians and children, but this clinical scenario is not one. Amputated digits in which the warm ischemia time has exceeded 12 hours are usually poor candidates for replantation; however, fingers have been reimplanted after 54 hours of cold ischemia time. Infection is a risk in any case of replantation, but the risk may be kept to a minimum by appropriate use of antibiotics and thorough surgical debridement. Patients with sharp injuries such as this one are the best candidates for replantation.

Answer 131

The correct response is Option E. The clinical and angiographic findings are most consistent with hypothenar hammer syndrome, which is thrombosis of the ulnar artery and proximal superficial arch. This syndrome is the most common type of post-traumatic upper extremity arterial occlusion and results from repetitive injury to the hypothenar region of the hand. Symptoms of pain, cold sensitivity, and numbness are common after thrombosis of the artery within Guyon’s canal. The syndrome occurs most commonly in male laborers who usually use the palm of the hand as a hammer, resulting in injury to the ulnar artery as it is crushed between the roof of Guyon’s canal and the hook of the hamate and pisiform. Patients with this condition are often smokers. Treatment consists of resection of the thrombosed segment followed by vein grafting. Previous treatments include ligation of the artery alone. Smoking cessation, calcium channel blocker therapy, and biofeedback have all been used to treat vasospastic conditions of the hand and would not be effective in this situation.

Answer 132

The correct response is Option A. In this patient, age is the primary indication for replantation. In the pediatric population, replantation is indicated for any amputation. Other indications for replantation include thumb amputations, multiple-digit amputations, and single-digit amputations distal to the flexor digitorum superficialis (FDS) tendon insertion. This patient’s injury is through the proximal interphalangeal joint and, therefore, is proximal to the FDS insertion. The duration of tissue ischemia can have a profound effect on the outcome of replantation, depending on the amount of muscle involved. Warm ischemia time should not exceed 12 hours for digits and should not exceed six hours for any amputation proximal to the wrist. Ischemia time is significantly prolonged by cooling the amputated part to 10 degrees Celsius. Ischemia time for digits is extended to 24 hours, whereas major limbs can survive 12 hours. Warm ischemia time less than 12 hours is favorable. Method of injury often dictates whether the amputation is salvageable. Guillotine-type amputations are very good candidates for replantation. Injuries that cause additional local trauma (such as from table saws), avulsion injuries, and crush-type injuries generally create amputations that are difficult to replant. Single-digit amputation, in itself, is not an indication for replantation even if it involves the dominant extremity.

Answer 133

The correct response is Option E. Because of his occupation, this patient requires the best sensation and the most rapid treatment possible. Local flaps such as cross-finger and thenar flaps are good options but require at least two operations (inset then division) and can result in stiffness. Local flaps also have lesser return of sensibility than the other techniques listed. Return of tactile sensibility is excellent after treatment with application of dressings. However, dressing changes for wounds that measure a total of 2 cm2 require a lengthy recovery time. This patient would undergo two to three months of dressing changes. Skin grafting would be the next available option with acceptable sensory return. It is an operation that can be performed during local anesthesia, requires only one operation, and would allow for early motion. Interestingly, classic studies have shown that full-thickness skin grafts recover sensation better than split-thickness skin grafts. A radial forearm flap will be excessively bulky and is not warranted. This procedure will result in inadequate sensory recovery.

Answer 134

The correct response is Option A. In patients with established connective tissue disease and small vessel disease of the hand, the most appropriate management of painful ulcerations of the fingertip is conservative amputation. The degree of dermal bleeding at the site of amputation can be used to assess the likelihood of healing. Digital sympathectomy is also a possible management of this lesion. Digital arterial bypass is unlikely to succeed in patients with small vessel occlusive disease. Skin flaps should be loosely approximated without tension. Distally based digital flaps are highly unlikely to succeed in patients with small vessel disease. Full-thickness skin grafting is unlikely to succeed in this patient because the wound extends into the joint, the finger is ischemic, and the wound bed is unlikely to provide adequate vascularity for the skin graft. Larger surgical procedures, such as ray amputation, are not indicated as a first choice in this patient, because of the increased incidence of complications and wound-related problems.

Answer 135

The correct response is Option D. The thenar flap is ideal for young patients with a volar defect of the index or long finger. These patients are not likely to have stiffness, and the radial digits are in proximity to the volar metacarpophalangeal joint of the thumb. A reverse cross-finger flap is used to cover dorsal defects on adjacent digits. In this patient, a cross-finger flap is not an option because of the lacerations to the long finger. Revision amputation is an option, but in this young woman it is preferable to preserve the nail and finger length for functional and cosmetic reasons. Healing by secondary intention is not appropriate for patients with injuries involving exposed bone and tendon. Secondary healing is ideal for young patients but is usually reserved for smaller defects. A V-Y advancement flap is indicated for distal tip amputations, but it is not an option in this patient because there is significant volar loss at the insertion site of the flexor digitorum profundus tendon on the proximal base of the distal phalanx. V-Y advancement flaps can be designed volarly or laterally. The volar flap is most useful when the volar skin is longer than the dorsal skin. The lateral flaps are designed bilaterally over the midlateral line and advanced to the tip, leaving a longitudinal incision at the tip of the digit.

Answer 136

The correct response is Option C. Associated life-threatening conditions are the only true contraindications to replantation of an amputated part. All other concomitant conditions, such as diabetes mellitus or psychiatric disorders, are relative contraindications, and the risks and benefits of replantation should be weighed in patients with these conditions. A history of smoking may affect the success of the replantation but is not an absolute contraindication. In some patients, multilevel amputations can be replanted successfully, especially if the amputation is sharp and/or guillotine-like. Although a self-inflicted amputation in a patient with an underlying psychiatric disorder is problematic, replantation is not contraindicated absolutely. In patients who sustain single-digit amputations, replantation is relatively contraindicated because the risk for functional loss in the adjacent fingers is high in relation to the possible functional gain that will result. Replantation is strongly indicated in patients with amputations of multiple digits or of the thumb. Replantation is easier and is more likely to be successful in patients with sharp, guillotine-like amputations than in those with ragged, avulsion, or crush-type injuries. In general, amputations distal to the insertion of the flexor digitorum superficialis (FDS) tendon (zone I) are associated with a better functional outcome than amputations proximal to the insertion of the FDS tendon (zone II).

Answer 137

The correct response is Option C. When the proximal interphalangeal (PIP) joint is flexed for an extended period, the neurovascular bundles shorten. During contracture release, extension of the PIP joint must be performed judiciously. It may be necessary to accept a less-than-perfect PIP joint correction in an effort to prevent stretching of the digital arteries, which can cause insufficient perfusion distal to the PIP joint. After joint release and splinting, regular follow-up is necessary to ensure adequate perfusion. If vascularity is a concern, the surgeon must remove the splint and flex the finger to relax the digital arteries. Vasospasm typically resolves and does not result in postoperative necrosis. Bilateral digital artery laceration loss would result in complete digital loss. Intra-arterial injection of a local anesthetic agent would not result in postoperative necrosis. A retained digital tourniquet, not a tight splint, would cause postoperative necrosis.

Answer 138

The correct response is Option A. Ring avulsion injuries have been classified as follows: Class I: Circulation adequate; standard bone and soft-tissue treatment is indicated Class II: Circulation inadequate; vessel repair is required for viability Class III: Complete degloving or amputation is required This patient has sustained a complete degloving avulsion, which qualifies as a Class III injury. Although management of ring avulsion injuries remains controversial, the recommended approach for these severe injuries is completion of the amputation. Burial of the finger’s skeletal structures into an abdominal pocket does nothing toward constructing a functional finger. Class I injuries, which have adequate circulation, and Class II injuries, which have inadequate circulation, can be reconstructed successfully in most cases. Reconstruction of these less severe injuries can be effected by various microsurgical procedures and skin flap reconstructions. This patient underwent shortening and closure of the amputation stump. He was able to return to his vocation as a mechanic approximately two weeks after the original injury.

Answer 139

The correct response is Option A. In recent clinical trials, collagenase injection has been shown to be effective in enzymatic digesting the finger cords that cause Dupuytren’s contracture. This procedure corrects flexion deformities of the MP joint but not contracture of the proximal interphalangeal (PIP) joint. Relief of PIP joint contracture requires radical fasciectomy and volar plate release. Tendon rupture, neuropraxia, and wound complications are infrequent with this procedure. Use of collagenase will not prevent future recurrence of Dupuytren’s contracture.

Answer 140

The correct response is Option C. Dupuytren’s disease is a contracture of the palmar fascia of the hand. The etiology is unclear. In patients with this condition, diseased structures of the palmar fascia contract, causing contracture of the palm and digits. The normal fascia and bands of the hand become contracted cords. The spiral cord is composed of the pretendinous band, the spiral band, the lateral digital sheath, Grayson’s ligament, and the vertical band. Contracture of the spiral cord can displace the neurovascular bundles of the fingers toward the midline proximally and superficially, rendering the vascular structures of the nerve more susceptible to injury during surgical release. Cleland’s ligament is not involved in Dupuytren’s disease and/or the spiral cord. The dorsal digital fascia is separate from Cleland’s ligament and develops into the retrovascular cords. The natatory ligament and transverse fibers of the palmar fascia are transversely oriented structures and are not involved in the spiral cord.

Answer 141

The correct response is Option B. The kite flap is most appropriate for coverage of this patient’s defect. This flap is based on the first dorsal metacarpal artery, which emerges from between the dorsal interosseus muscles and travels over the proximal aspect of the index finger. It is appropriate for coverage of defects as large as 4 _ 3 cm and may include a large skin paddle. The superficial radial nerve branch and dorsal digital nerve branch can be harvested with the kite flap to supply sensation. Venous drainage is provided by the venae comitantes and dorsal veins. The donor site of the kite flap can be covered easily with a skin graft. However, motion of the donor index finger may be diminished. The Littler flap is a neurovascular island flap that is typically based on the third common neurovascular bundle. However, this flap is technically more difficult than the kite flap. Although it is a sensate flap, significant cortical reorientation is required. In addition, its venous drainage occurs via the venae comitantes alone, making it less reliable. This flap should be harvested from the nonopposition side of the long or ring finger and over the full palmar aspect of the finger to obviate the need for a skin graft for the donor defect. The radial forearm flap supplies greater surface area than required. Skin grafts will not take over exposed bone and tendon. The Moberg flap is appropriate for coverage of small defects (up to 1.5 cm) of the tip of the thumb.

Answer 142

The correct response is Option A. Because thumb length is critical to hand function, including opposition of the thumb to the fingers, defects of the thumb tip should be managed conservatively. Shortening and/or revision amputation should be avoided if possible. Of the two flaps used for thumb reconstruction, the first dorsal metacarpal artery flap is preferred over the Littler neurovascular island flap because a large vein can be included with the venae comitantes. There is decreased morbidity at the donor site, and the prospects for cortical reorientation of sensation on the thumb are better. Young patients can relearn to interpret pressure on the thumb flap as the thumb and not as the original long finger donor. This patient’s defect is too large for a Moberg flap. The exposed bone might impede proper healing of a skin graft.

Answer 143

The correct response is Option E. Simple and stellate matrix lacerations of the nail bed should be managed by primary repair of the nail at the time of injury. Healing by secondary intention without anatomic alignment can result in increased scar tissue in the nail bed. As the nail plate regenerates, the nail will not properly adhere to the nail bed, causing deviation of the nail away from the finger as well as subsequent trauma and discomfort. Sterile nail bed injuries that involve lost tissue should be corrected with a sterile nail bed graft. Loss of the germinal matrix requires a full-thickness germinal matrix graft.

Answer 144

The correct response is Option B. In patients with type III avulsion injury of the ring finger, the soft-tissue envelope detaches completely from the base of the finger. The zone of injury is extensive and the extent of arterial vessel injury cannot be determined, even with microscopy. Recent technical modifications have focused on revascularizing the amputated digit as distally as possible to bypass the injured arterial segments. Effective techniques include long vein grafting or transfer of the ulnar digital artery from the long finger to anastomose the digital artery at the level of the distal interphalangeal joint. The transposition technique appears to be simpler because it affords exact matching of luminal diameters and involves only one anastomosis. Although amputation for type III avulsion injury has been advocated in the past, recent research has shown that judicious replantation efforts may achieve a better functional and aesthetic outcome. Replantation requires recreation of arterial flow. Due to the extent of injury to the native arteries, an arterial source is required from an adjacent digit, i.e., the long finger ulnar digital artery. A native artery inflow source would thrombose due to the intimal injury. Leech application is useful for inadequate venous outflow. Successful arterial inflow, not systemic heparinization or relatively short ischemic time, is critical for success of replantation.

Answer 145

The correct response is Option C. The carpal canal contains nine tendons: the flexor pollicis longus and the four slips of both the flexor digitorum superficialis and the flexor digitorum profundus. The ulnar nerve is contained within Guyon’s canal, which is bordered by the pisiform ligament, hook of the hamate ligament, and pisohamate ligament. The flexor carpi ulnaris partly forms the volar boundary of Guyon’s canal. The flexor carpi radialis is contained within its own flexor sheath outside the carpal canal. The palmaris longus, which is also outside the carpal canal, continues into the palm as the palmar aponeurotic expansion. The brachioradialis is an accessory elbow flexor that crosses the elbow and inserts into the distal radial aspect of the radius. The pronator teres is the most superficial of the forearm muscles and inserts into the radius proximal to the level of the wrist. The abductor pollicis longus and extensor pollicis brevis are located within the first dorsal compartment. The lumbrical muscles arise from the flexor digitorum profundus tendons at the level of the palm and are typically distal to the carpal canal. The palmaris brevis is a vestigial muscle that partly constitutes the prominence of the proximal aspect of the hypothenar eminence of the hand. The palmar cutaneous branch exits from the median nerve at the level of the distal third of the forearm on the radial aspect of the flexor carpi radialis tendon as it travels toward the scaphoid tuberosity.

Answer 146

The correct response is Option B. In patients undergoing ray amputation of the finger, the space between the small and long fingers is closed by suturing the deep intervolar plate ligaments. Another technique that can be used to close the gap between the long and small fingers is ray transposition, which involves transferring the base of the metacarpal of the small finger to the base of the ring finger. However, ray transposition often requires a longer period of immobilization to allow the osteotomy to heal. Suture of the collateral ligaments, extensor tendons, flexor tendons, and sagittal bands would create a tether and limit tendon excursion and range of motion.

Answer 147

The correct response is Option D. The thenar flap is most appropriate for reconstruction of this patient’s defect. This flap can be used to effectively reconstruct defects of the tips of the index and long fingers, which flex comfortably into the thenar eminence. In contrast, because the ring and small fingers have difficulty reaching the thenar crease, defects of these fingertips can be covered instead using a hypothenar flap from the ulnar side of the hand. Split-thickness or full-thickness skin grafting is inappropriate over exposed bone, and padding is required for coverage of any fingertip defect. Moberg flaps are recommended for coverage of soft-tissue defects of the volar pad of the thumb. The dorsal circulation of the thumb allows for the extensive soft-tissue mobilization required with this flap. The neurovascular bundles are elevated with the Moberg flap. A reverse cross-finger flap is used to cover defects of the dorsal aspect of the finger. With this flap, subcutaneous tissue is harvested from the dorsal and not the volar aspect of the finger; therefore, the neurovascular bundles are not disrupted. A cross-finger flap cannot be used in this patient because the dorsal skin of the long finger is avulsed. Likewise, a volar V-Y advancement flap is not possible because the volar skin pad of the index finger has also been avulsed. Although the dorsal skin is intact, it should not be used for coverage because the patient would like to preserve finger length, and because the risk for development of a hook nail deformity would be increased if the dorsal skin were transferred.

Answer 148

The correct response is Option A. In this 63-year-old man who has limited extension of the proximal interphalangeal (PIP) joint of the left small finger that has occurred as a result of a Dupuytren contracture, the central and lateral cords are the most likely cause. Diseased cords evolve from the normal fascial bands of the hand in patients with Dupuytren disease, leading to flexion deformities of the affected joints. Fascial structures of the hand that may contribute to Dupuytren contracture include Grayson’s and Cleland’s ligaments, the lateral digital sheath, the natatory ligament, the pretendinous and spiral bands, and the superficial transverse ligament. The central, lateral, and spiral cords cause flexion contractures of the PIP joint. The central cord arises from the pretendinous band, and the lateral cord is formed from the central digital sheath. The spiral cord is composed of the pretendinous and spiral bands, lateral digital sheath, and Grayson’s ligament. Contraction of the spiral cord results in medial and superficial displacement of the neurovascular bundle. In addition to the contracture of the PIP joint caused by the central and lateral cords, this patient’s hand posture results from contracture of the metacarpophalangeal joint caused by the action of the pretendinous cord. The pretendinous cord does not contribute to contractures of the PIP joint. The natatory cord is formed from the natatory ligament as it passes transversely across the palm at the level of the web spaces. It causes adduction, not flexion, contractures of the digits.

Answer 149

The correct response is Option E. Ring avulsion injuries are typically associated with the highest failure rates following replantation, most likely because of the mechanism of injury, which involves destruction of the intimal layer of the supporting vasculature. In this patient, revascularization has failed, leaving a necrotic digit. The most appropriate next step in management of this patient is ray amputation, which involves removal of the entire digit and most or all of the metacarpal. Completely removing the digit eliminates the segmental loss and greatly improves both function and aesthetic appearance, as shown in the photographs above. Resection of nonviable soft tissue results in exposure of the phalanges and tendons. A full-thickness skin graft will not take over these exposed structures. The Littler neurovascular island flap is based on the digital neurovascular bundle of either the long or ring finger. This flap provides sensate coverage of smaller digital defects, particularly the thumb, but would not cover the entire defect in this patient. Replacing the long finger with a toe-to-hand transfer is impractical, as the transferred digit would be significantly shorter than the adjacent digits and would ultimately impair their function. This technique is appropriate for patients who have sustained amputations of the thumb or of multiple digits. Simple revision amputation is the easiest method of skin closure but leaves a large gap between the long and small fingers, allowing an area through which small objects can fall, and thus limiting hand function.

Answer 150

The correct response is Option E. In this patient who has a split nail deformity, the most appropriate management is full-thickness nail grafting from the toe. This deformity is caused by injury to the nail bed, leading to scarring of the bed. The nail plate does not grow in the scarred area, resulting in a split in the nail plate. Because the deformity involves both the sterile and germinal matrices, only a full-thickness nail will provide the sterile and germinal matrix components required for reconstruction. Harvest of a full-thickness nail produces a significant cosmetic defect at the donor site; therefore, a graft from the second toe is thought to provide the least unsightly result. In patients who have a small scar affecting the sterile matrix only, appropriate management may include excision of the scar and re-approximation of the sterile matrix; however, the sterile matrix is not usually mobilized and re-approximated unless the affected area is narrow. In addition, the germinal matrix cannot tolerate re-approximation. As mentioned above, a split nail graft from either the same nail bed or another nail bed will not provide the components needed for reconstruction of this defect. In addition, using another finger as a donor will result in an unsightly donor defect in the hand.

Answer 151

The correct response is Option D. Fascial structures that encase the neurovascular bundles include Cleland’s and Grayson’s ligaments, the lateral digital sheet, and the retrovascular band. Cleland’s ligament is a thick fascial structure that lies deep to the neurovascular bundle; it arises from the side of the phalanges and courses obliquely toward the skin. Grayson’s ligament is thinner and more sheet-like than Cleland’s ligament, and is positioned superficial to the neurovascular bundle; it arises from the tendon sheath and extends to the skin. The lateral digital sheet is comprised of superficial fascia on either side of the phalanges. It receives fibers from the natatory ligament and the spiral band, and is found lateral to the neurovascular bundle. The retrovascular band is a longitudinal structure situated dorsomedial to the neurovascular bundle. The pretendinous cord is a pathologic component of Dupuytren disease. It is an extension of the pretendinous band in the midline of the phalanges. The pretendinous band is not a component of the fascia surrounding the neurovascular bundles.

Answer 152

The correct response is Option C. In this 27-year-old machinist who has a lumbrical-plus deformity secondary to release of the flexor digitorum profundus tendon to the index finger, the most appropriate management is sectioning or division of the lumbrical muscle. Because the profundus tendon to the index finger is independent, proximal retraction causes proximal retraction of lumbrical tendon, leading to increased tension. With attempted flexion of the proximal interphalangeal (PIP) joint (ie, to make a full fist), the lumbrical muscle migrates more proximally, exerting tension on the extensor mechanism through the lateral band. Paradoxical extension of the interphalangeal joints results. Sectioning of the muscle can be performed as an outpatient procedure using a local anesthetic. Osteotomy of the middle phalanx will not correct the muscle-tendon imbalance. Release of the sagittal bands is most likely to result in subluxation of the extensor tendons across the metacarpophalangeal joint. Tenolysis of the profundus tendon is appropriate for management of flexion contractures with adhesions, and transfer of the interosseous muscle is performed for correction of ulnar drift in patients with rheumatoid arthritis.

Answer 153

The correct response is Option B. In this patient who has sustained a stellate laceration of the nail bed of the long finger, the most appropriate management is primary repair of the nail bed. Lacerations of the nail bed are common injuries that most frequently occur in the long finger, as it is typically the last digit to be moved during a situation of potential trauma to the hand. Injury to the nail bed can be classified as simple laceration, stellate laceration, avulsion, crush injury, or amputation. The most appropriate management of simple and stellate lacerations of the sterile matrix is primary repair. These injuries are associated with the best prognosis; the nail typically has a normal appearance after healing. In patients with avulsion and crush injuries, the outcome is often variable, as fracture of the distal phalanx may be associated. Any fracture that occurs must be reduced initially to eliminate irregular bone contours, which often result in a nail deformity. If there is contamination of the nail bed, the necrotic tissue is debrided. Split matrix grafting, using sterile grafts obtained from an adjacent portion of uninjured nail bed, can be performed for reconstruction. A split nail bed graft can be harvested also from the great toe. Healing by second intention would result in deformity of the nail bed. Germinal matrix grafts are appropriate for repair of trauma to the germinal matrix of the nail. These are full-thickness grafts that leave a deformity at the donor site following harvest. Reconstruction of the nail bed with a free flap is reserved for management of chronic deformities of the nail and is not considered in patients with acute injuries.

Answer 154

The correct response is Option D. In addition to the experience of the surgeon, the mechanism of injury is most likely to influence the success of replantation in any patient who has sustained an amputation of a digit. Because the vessels of the amputated part are damaged in patients who sustain avulsion and crush amputations, perfusion will be impeded, decreasing the likelihood of successful replantation. In addition, cooling of the amputated part contributes to the success of the replantation, as the amputated part can be replanted as late as 24 hours after injury if it is well preserved. The age of the patient does not affect the success rate of replantation in the absence of other comorbid conditions or a history of cigarette smoking. Likewise, hematocrit and a history of hand surgery generally do not influence the outcome of replantation significantly. Because digits do not contain muscle, the length of ischemia time is not an influential factor.

Answer 155

The correct response is Option C. In this patient who has a pincer or trumpet nail deformity, the most appropriate management is lateral elevation of the nail matrix and dermal autografting. This deformity of unknown cause is characterized by excess transverse curvature of the nail and progressive pinching of the soft tissue of the distal fingertip, resulting in a painful, unattractive deformity. To correct this, the nail plate is removed, the nail bed is elevated from the sides of the distal phalanx, and dermal grafts are placed under the lateral and medial portions of the nail bed. Another management option is surgical ablation of the nail matrix and full-thickness skin grafting. Topical application of podophyllin is appropriate for treatment of digital or plantar warts. Removal of the nail plate or toenail transplantation would not correct the underlying distorted matrices, and the new nail would continue to grow in the same pattern. Split matrix grafting is used for nail reconstruction in patients who have bifid nails or eponychial or hyponychial pterygium, in which the nail bed is scarred or the nail plate does not adhere to the nail bed.

Answer 156

The correct response is Option C. Dupuytren's diathesis is an aggressive form of Dupuytren's contracture associated with knuckle pads, involvement of the plantar fascia, and Peyronie's disease, or thickening of the tunica albuginea of the penis. Dupuytren's diathesis has an earlier age of onset and a more rapid progression than Dupuytren's contractures, and is more likely to be bilateral and to involve the radial side of the hand. In contrast, Dupuytren's contractures typically affect the ulnarmost digits. Heberden's (DIP) and Bouchard (PIP) nodes, which affect the distal interphalangeal and proximal interphalangeal joints, respectively, occur in association with osteoarthritis of the hand. Patients with Dupuytren's diathesis who undergo surgery have been shown to be at increased risk for development of a flare response with early recurrence or extension of the condition. A flare response is a type of extreme, focal reflex sympathetic dystrophy or complex regional pain syndrome that occurs after surgery for Dupuytren's contracture and is associated with hypersensitivity and skin discoloration. Flexor tenosynovitis occurs in patients with trigger finger or rheumatoid arthritis. Thrombophlebitis, sclerodactyly, trophic changes in the fingers, and decreased temperature in the fingers and/or hand are symptomatic of vascular conditions such as ischemia, scleroderma, or Raynaud's disease.

Answer 157

The correct response is Option A. The findings in this 40-year-old construction worker are consistent with hypothenar hammer syndrome. In this condition, there is increased pressure caused by significant trauma to the hand, resulting in crushing of the ulnar artery at Guyon's canal. This produces a true aneurysm that can shower emboli to the digits. The ischemic symptoms in the long, ring, and small fingers are caused by an incomplete superficial arch and excessive sympathetic activity resulting from localized inflammation in the region of Guyon's canal, adjacent to the ulnar nerve. Doppler ultrasonography shows occlusion of the ulnar artery at that location and patency of the radial artery and the superficial arch. Following arteriography, the thrombosed segment of the ulnar artery is excised. The success of arterial reconstruction using a reverse saphenous vein graft depends on the vascularity of the digits. In this patient, reverse saphenous vein grafting was successful, immediately restoring pulsatile flow to the three ulnarmost digits. Maffucci syndrome is a rare disorder that is characterized by multiple enchondromas associated with vascular hemangiomas. Because the risk for chondrosarcoma is increased, frequent follow-up examination is required. Raynaud's phenomenon is a progressive vasospastic condition that typically occurs in middle-age women. Affected patients develop nonhealing ulcers and gangrenous changes of the fingertips due to inadequate tissue perfusion. Cold stress vascular testing can be used in diagnosis. Patients with thoracic outlet syndrome have sensorimotor findings in the distribution of C8-T1 resulting from compression of the subclavian artery and lower trunk of the brachial plexus. Symptoms include occipital headaches, numbness in the fingers (especially the small finger), and pain in the shoulder and chest that is exacerbated when the arm is lifted above the level of the shoulder. Occlusion of peripheral arteries is not associated. Thromboangiitis obliterans, or Buerger's disease, manifests as gangrene of the fingertips. This condition typically occurs in middle-age patients who smoke. Arteriography shows diffuse atherosclerotic plaques in the digital arteries. Management includes cessation of smoking.

Answer 158

The correct response is Option D. When contemplating replantation of multiple digits, it is important to choose a management plan that maximizes the potential for survival of each replanted digit. For instance, in patients with sharp amputations, there is a better prognosis for replantation than in patients with avulsion-type amputations or crush amputations. The level of injury also helps determine the usefulness of the digit. In a patient who has sustained amputations of all digits, the relative importance of replantation is guided by the contribution of each digit to overall hand function. Because the thumb is generally believed to be the most important digit, its preservation is a priority. Although the index finger is generally important for fine motor pinch, the long finger can perform its functions in its absence. The two ulnarmost digits provide power grasping functions of the hand. In a five-digit replantation, the thumb is thought to be the most important digit, followed by either the long or ring finger, with replantation of the index finger being least important. Optimal repair has been shown to occur with a structure-by-structure approach, rather than a digit-by-digit approach. Most surgeons agree that bone and tendons should be repaired initially, followed by either vein or artery repair. The nerves should be repaired last. The AMA Guides to the Evaluation of Permanent Impairment are used to assign an impairment percentage to each amputated digit. Impairment can be calculated based on the level of amputation and the involved digit; each digit is given a value relative to the whole hand. The thumb is given a value of 40%, the index and long fingers values of 20% each, and the ring and small fingers values of 10% each. In addition, amputation through each portion of a digit is assigned a relative value of loss to the entire digit. Amputation through the metacarpophalangeal joint of a digit is assigned a value of 100%, and amputation through the proximal interphalangeal joint has a value of 80%. Amputation through the interphalangeal joint of the thumb is given a value of 50%. Amputation through the distal interphalangeal joint has a value of 45%.

Answer 159

The correct response is Option B. Transposition of the index finger to the long finger is best accomplished at the level of the metacarpal base. This provides a greater volume of cancellous bone at the metaphyseal flare, resulting in a higher rate of bony union. There is an increased incidence of nonunion if the osteotomy is performed too distally. Ray resection of the metacarpal of the long finger can also be performed in this patient, and the deep transverse metacarpal ligaments between the index and ring fingers can be sutured to close the web space. However, the width of the palm decreases following ray amputation, and grip strength may be diminished. In contrast, preservation of the metacarpal also preserves palmar width, but leaves a functional midhand gap in the areas of the missing digits. If transposition were performed at the level of the carpometacarpal (CMC) joint, CMC arthrodesis would be required. Transposition of the index finger at the metacarpal head will stretch the neurovascular bundle, increasing the risk for injury to the nerves and/or vessels. Transposition at the level of the metacarpophalangeal joint will result in a stiff joint.

Answer 160

The correct response is Option C. The most appropriate management is coverage with a palmar advancement flap, also known as a Moberg flap. This flap provides durable and sensate skin to the pulp of the thumb and preserves length. Although it can be used to cover defects as large as 2 \* 2 cm, it is more typically used for defects that have a length of 1 to 1.5 cm. Flap transfer involves mobilization of both digital arteries and nerves and advancement of volar skin, resulting in a minimal flexion deformity. Healing by second intention is contraindicated in a patient who has a defect involving exposed bone. Full-thickness skin grafts can be used for reconstruction of small defects but would result in an insensate thumb. In addition, grafting over exposed bone does not provide adequate coverage for pinch functions. Although transfer of pulp from the second toe may be indicated for thumb reconstruction, it is not the procedure of choice in a 67-year-old farmer. Coverage with a neurovascular island skin flap derived from the long finger is appropriate for reconstruction of large defects that involve sensate pinch on the radial aspect of the thumb. This technique is often performed secondarily if other first-line methods fail to restore satisfactory sensation.

Answer 161

The correct response is Option A. In this 10-year-old boy who has developed venous congestion after undergoing thumb replantation, it is important to remove all dressings and splints initially and examine the thumb. If improvement does not occur following removal of the dressings, suture removal is indicated because the closure may be constricting the digit and obstructing venous outflow. Other potential causes of venous obstruction include development of a hematoma or bleeding onto the dressing, which may cause the dressing to harden into a "blood cast." If these measures fail to resolve the congestion, intravenous administration of heparin, leech therapy, or heparin-induced matrix bleeding may be considered. If symptoms do not improve or worsen instead, repeat operative exploration of the venous and in some cases arterial anastomoses is warranted. Amputation of the thumb in a child is only indicated if all other measures have failed.

Answer 162

The correct response is Option D. The first dorsal metacarpal artery courses within the fascia of the first dorsal interosseous muscle; in rare cases, it may lie within the muscle itself. It communicates with the perforators from the superficial palmar arch at the level of the metacarpophalangeal joint. The first dorsal metacarpal artery flap is axially patterned and based on a terminal branch of the radial artery after it exits the region known as the anatomic snuff box. This region is bordered volarly by the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons (first dorsal compartment) and dorsally by the extensor pollicis longus (EPL) tendon (third dorsal compartment). The skin paddle of this flap is obtained from the dorsal aspect of the index finger over the proximal phalanx, and the venae comitantes and superficial veins provide venous drainage.

Answer 163

The correct response is Option C. Dupuytren's disease is an autosomal dominantly inherited disorder of unknown etiology that involves benign fibroproliferation of the palmar fascia. This condition occurs almost exclusively in Caucasian persons and is rare in African American and Asian American persons. It is most likely to develop in patients between 40 and 60 years of age, and men are seven to 15 times more likely to require surgery than women. Patients with diabetes mellitus are at greater risk for development of Dupuytren's disease. Contractures of the metacarpophalangeal (MP) and proximal interphalangeal (PIP) joints have been shown to result from distinct fascial elements. The central, lateral, retrovascular, and spiral cords cause contractures of the PIP joint. Grayson's ligament and the lateral digital sheath, pretendinous band, spiral band, and vertical band contribute to the spiral cord. The natatory ligament is the only web coalescence structure that is not involved in a contracture of the PIP joint. Division or resection of the involved cords is indicated in patients with joint or web space contractures that inhibit hand function. Surgery should be considered in patients who have MP joint contractures of more than 30 degrees or any type of flexion contracture involving the interphalangeal joints.

Answer 164

The correct response is Option D. The most appropriate management in this 3-year-old child who has a minimal fingertip defect is replacement using the amputated tip as a composite graft. The results are often good in children who undergo composite grafting of modest fingertip defects because the amputated part typically survives completely. Healing by secondary intention is appropriate for small defects without exposed bone, which may dessicate during the prolonged recovery period. Moist dressings can be used to cover the wound, but this becomes less optimal if the amputated tip is available for grafting. Split-thickness and full-thickness grafts should not be placed directly over exposed bone. A thenar flap is more appropriate for defects of the index and long fingers. In order to use this flap, the small finger must reach the thenar crease, which is difficult.

Answer 165

The correct response is Option C. Studies have shown that approximately 80% to 95% of patients with fractures of the distal phalanx have an associated nail bed laceration, making this the most commonly associated physical finding. In contrast, 60% of persons who have a subungual hematoma involving more than 50% of the nail have an associated nail bed laceration. These lacerations are seen more frequently in children and adolescents and are typically caused by crush injuries, in which the affected digit is caught in a door or window. The long finger is most often affected. In a patient who has either a fracture of the distal phalanx or a large subungual hematoma, the nail plate should be removed and the nail bed inspected under direct visualization. Nail bed lacerations can be repaired using small (6.0 or 7.0) absorbable sutures, which will prevent long-term nail ridging. The nail plate should then be replaced beneath the eponychial fold, where it will prevent the development of adhesions between the eponychial fold and nail matrix (termed "synechia"). Nail bed lacerations are not commonly associated with closed division of the extensor tendon or dislocation of the distal interphalangeal joint. Digital nerve neurapraxia is common in patients who sustain significant crush injuries to the fingertip but is not a predictor of nail bed lacerations.

Answer 166

The correct response is Option D. The thumb has a dual blood supply, which allows for harvest of volarly based flaps (such as the Moberg flap) without compromising digital perfusion. With the Moberg flap, volar tissue based on both neurovascular bundles is advanced. The edge of the defect comprises the distal limit of the flap. Lateral incisions are made between the dorsal and volar skin; the flap is dissected distally to proximally and raised from the remaining periosteum and flexor tendon sheath to include both digital arteries and digital nerves to the level of the metacarpophalangeal joint crease. Following harvest, the thumb joints are splinted in flexion for two to three weeks. Although pulp sensibility is near normal with the use of this flap, thumb stiffness may be seen. The typical Moberg flap can be advanced 1 to 1.5 cm. The skin at the base of the flap can be divided, and the subcutaneous tissue can be covered with a skin graft. Larger defects can be reconstructed using either a neurovascular island flap from the index, long, or ring fingers or a free tissue transfer from the great toe.

Answer 167

The correct response is Option C. The findings in this patient are most likely caused by the development of a lumbrical plus deformity. Patients with this deformity have paradoxical extension of the proximal interphalangeal (PIP) joint during attempted flexion; the finger often catches on objects. Common causes of the lumbrical plus deformity include distal amputations, excessively long flexor digitorum profundus (FDP) tendon interposition grafts, and excessive FDP tendon lengthening procedures. A patient with extrinsic extensor tendon adherence or scarring will have limited flexion across the metacarpophalangeal and PIP joints without paradoxical extension of the finger. The flexor digitorum sublimis tendon is still intact at the level of the distal interphalangeal joint. The quadriga effect results from adherence of the FDP tendon to the amputation stump. In patients with this condition, tethering of the FDP tendon in the injured finger leads to decreased motion and strength in the uninjured fingers. Posttraumatic stiffness would inhibit both passive and active range of motion of all joints in the hand.

Answer 168

The correct response is Option B. Because the radial digital artery of the ring finger is typically less important to finger perfusion, it is routinely ligated during mobilization of a neurovascular island flap from the ulnar aspect of the long finger. This flap, which is used in thumb reconstruction, derives its sensory innervation from the ulnar digital nerve. Although the flap can be harvested from the nontactile aspect of any digit, the ulnar aspect of the long finger is often used. Adequate blood flow in the ulnar digital artery of the ring finger and radial digital artery of the long finger must be ensured prior to flap harvest using either Doppler ultrasonography or an Allen's test. The ulnar digital artery and nerve of the long finger are included with the skin flap along with a cuff of fibrofatty tissue for venous drainage. During dissection, the common digital arteries in the palm, which are branches of the superficial palmar arch, are identified first. The patency of the radial digital artery of the long finger and ulnar digital artery of the ring finger are confirmed, and the flap is harvested with the included structures identified above. The radial digital artery of the ring finger is divided. The proper ulnar digital nerve of the long finger may be dissected proximally from the common digital nerve to allow for tension-free transposition.

Answer 169

The correct response is Option A. The most appropriate first step in major limb replantation is establishment of blood flow. In any patient who sustains an amputation proximal to the level of the wrist, the blood supply must be reestablished within six hours of warm ischemia time (or 12 hours of cold ischemia time) to minimize the extent of myonecrosis. In a patient who seeks treatment immediately after sustaining an amputation, fasciotomies should be performed first, followed by bone fixation, arterial repair, vein repair, and then nerve repair. However, if the ischemia time is approaching the six-hour limit, temporary arterial shunting should be established with a Silastic endarterectomy shunt, small Foley catheter, or feeding tube. In patients who have prolonged ischemia, arterial flow should always be established before venous outflow. The arterial anastomosis should be opened to allow venous egress and to prevent the systemic return of lactic acid, which can result in detrimental complications.

Answer 170

The correct response is Option A. This 52-year-old man most likely has a Dupuytren's nodule; therefore, the most appropriate management is observation alone. Dupuytren's nodules are common in patients who have a history of plantar fibromatosis. Solitary nodules often remain unchanged for years, and only occasional follow-up examinations are required. Painful lesions can be treated with injection of a corticosteroid. Because Dupuytren's nodules contain abundant myofibroblasts that produce abnormal collagen, purified collagenase has been used with some success in management. Other conservative treatments including application of dimethyl sulfoxide (DMSO), interferon therapy, splinting, and ultrasonography have not been proven to be widely effective. Biopsy is not recommended for this nonmalignant lesion. Excision of a Dupuytren's nodule is rarely indicated.

Answer 171

The correct response is Option A. This patient's flexion contractures are most likely caused by involvement of the central cord. The central cord has no precursor band; it arises with the pretendinous cord and attaches to the tendon sheath or bone of the middle phalanx. It is the most common cause of contractures involving the proximal interphalangeal (PIP) joint. Contracted cords are typically seen on one side of the finger only; diseased cords on both sides are rare. The lateral and spiral cords can also cause flexion contractures of the PIP joint. In addition, the lateral cord can be a primary cause of flexion contractures of the distal interphalangeal joints. The spiral cords are composed of the spiral band, lateral digital sheath, and Grayson's ligament, which in the normal human hand form a spiral around the neurovascular bundle. However, in patients with Dupuytren's disease, the spiral cord contracts, causing the neurovascular bundle to form a spiral around the cord. Contraction of the spiral cord results in medial and superficial displacement of the neurovascular bundle. The development of a natatory cord typically results in loss of finger abduction and flexion contractures of the PIP joints. Some fibers of the natatory cord may pass distally on the sides of the affected finger. The pretendinous cords cause contracture of the metacarpophalangeal joint. These cords evolve from the pretendinous bands; contracture of these bands causes pitting in the palm.

Answer 172

The correct response is Option E. The photograph illustrates Littler's neurosensory island flap, which is based on the proper digital nerve to the ulnar aspect of the ring finger. This nerve is a terminal branch of the ulnar nerve. This flap is used to provide needed sensibility to the thumb and index finger pads. Its vascularity is supplied by the corresponding proper digital artery with venous return through multiple adventitial venae comitantes. The flap can be pedicled all the way to the superficial palmar arch by ligating the proper digital artery to the radial aspect of the small finger, creating a flap with adequate reach to resurface the volar aspect of the thumb. Adequate blood flow in the radial digital artery of the ring finger and ulnar digital artery of the small finger must be ensured prior to flap transfer. The common digital nerve to the fourth web space can be divided along the fascicles to allow for mobilization of the digital nerve to the level of the superficial arch. This patient has third-degree burns of the thumb with destruction of the digital nerves resulting from an electrocution injury. In order to restore function and sensibility in the thumb, the neurosensory flap is elevated from the ulnar aspect of the ring finger, tunneled across the palm of the hand subcutaneously, and inset into the perimeter of the thumb wound to provide sensation to the thumb pad. Flap vascularity is not supplied by the dorsal metacarpal artery or posterior interosseous artery. Nor do the radial and median nerves innervate the ulnar aspect of the ring finger, which would be transposed to provide sensation to the thumb pad.

Answer 173

The correct response is Option C. The patient has a burn wound with exposed tendon (no paratenon) over a joint. Appropriate coverage will permit tendon glide and joint motion. Sensation is not required. The kite flap can be based on the first or second dorsal metacarpal artery over the dorsal aspect of the index and long fingers, respectively. The flap territory includes the dorsal skin of the proximal phalanx of the index finger for the first metacarpal artery flap and the dorsal skin of the proximal phalanx of the long finger for the second metacarpal artery flap. The radial and dorsal proximal interphalangeal sensory branches can be used to create a sensate flap. The first dorsal metacarpal artery flap works well when used for coverage of dorsal thumb wounds; however, the second dorsal metacarpal artery flap will not reach the dorsal thumb. Coverage of this patient's wound with a skin graft will be unsuccessful. Neither a split- nor a full-thickness graft will heal over exposed tendon without paratenon, which will not provide adequate vascularization to support a skin graft. Additionally, the graft would adhere to the tendon. A Moberg flap advances volar tissue from the thumb pad 1 to 1.5 cm for volar pad coverage. A thenar flap is appropriate for index and long fingertip pad defects. The thenar flap will not reach the interphalangeal joint area of the dorsal thumb.

Answer 174

The correct response is Option C. An occlusive dressing consisting of a polyurethane foam and a hydrocolloid polymer complex (DuoDerm), or a semiocclusive dressing consisting of synthetic adhesive moisture vapor permeable films (eg, Op-Site, Tegaderm) will minimize patient discomfort, reduce the risk for infection, and decrease healing time. Fine mesh gauzes (eg, Scarlet Red, Vaseline, Xeroform) use the semiopen technique of wound healing. Epithelialization and infection rates are favorable, but, when compared with other dressings, pain and discomfort are greater. Another version of the semiopen wound-healing technique involves the use of a semipermeable silicone membrane and a knitted nylon fabric covalently bonded to porcine collagen (Biobrane). This method is more comfortable for the patient but is associated with a higher rate of infection following skin grafting. Biologic dressings (eg, cadaveric skin homografts, heterografts, porcine xenografts, amniotic membranes) are frequently associated with marked inflammation of the wound, delayed epithelialization, and prolonged wound healing times.

Answer 175

The correct response is Option E. This 45-year-old man sustained a multilevel crush injury to his right index finger, resulting in gangrenous changes at the level of the midportion of the midphalanx. In most patients who have extensive soft-tissue and nerve damage, the affected digit should be shortened to a level at which ample soft tissue is available for primary closure of the wound. However, complete ray amputation is recommended instead in this patient because the soft-tissue injuries extend proximal to the level of the distal interphalangeal joint. This single-stage procedure will securely close the soft tissues, allowing the patient to return to work sooner. In addition, oblique osteotomy should be performed through the proximal metacarpal flare, enhancing the curved web space. Hand function can be realized by allowing the middle finger to perform as an index finger during grasping. Healing by second intention is typically reserved for fingertip amputations without exposed bone. In this patient who has an extensive area of injury with contamination, second intention healing may result in the development of wound sepsis. Although dressing changes can aid in wound debridement, they would be inadequate in a patient with a severely injured and possibly contaminated digit. Staged reconstruction of the skin, tendons, nerves, and vessels would result in a stiff, insensitive digit that would be bypassed during hand activities. Amputation at the PIP joint is rarely indicated for the index finger. Amputation through the metacarpophalangeal joint would result in a prominent, cumbersome amputation stump and would provide no advantage over ray amputation because the intrinsic and extrinsic tendons have already been sacrificed.

Answer 176

The correct response is Option D. The most likely diagnosis in this 50-year-old woman is scleroderma, or primary systemic sclerosis. Characteristic findings in patients with scleroderma include shiny edema of the skin and stiffness of the joints. Vasospasm of the digits may lead to ischemia and ultimately to the ulceration typically associated with Raynaud's phenomenon. These conditions may occur concomitantly as part of the CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasias). Raynaud's disease is a vasospastic disorder characterized by triphasic color changes of the skin. This disorder has no gender predilection and typically has its onset in patients age 30 to 50 years. Hand symptoms are bilateral and dysesthesias of the extremities are associated. Symptoms must be present for two years before a definitive diagnosis can be made. In patients with Raynaud's phenomenon, there are episodic triphasic color changes of the digits following stress or cold exposure. Digital gangrene may result. This condition often occurs in patients with connective tissue disorders such as scleroderma. Patients with reflex sympathetic dystrophy have the sudden onset of diffuse pain and hypersensitivity of one extremity following surgery or trauma to the extremity. Signs and symptoms of reflex sympathetic dystrophy include diminished hand function, joint stiffness, color changes, and vasomotor instability. Systemic lupus erythematosus is an autoimmune disorder characterized by arthralgias of the hands, wrists, and feet and swelling of the joints. This condition typically affects women of child-bearing age. Neurologic involvement is common; a malar rash can also be seen.

Answer 177

The correct response is Option D. A kite flap will provide reliable soft-tissue coverage of this patient's wound. This axially patterned flap is based on the first dorsal metacarpal artery; it can be elevated from the dorsal aspect of the proximal phalanx of the index finger. In order to reach distal defects of the dorsal thumb, the surgeon should dissect proximally to the origin of the first dorsal metacarpal artery, just proximal to the bifurcation of the dorsal radial artery and into the princeps pollicis artery and deep palmar arch. Although this flap is technically demanding, it will provide optimal results. A dermal turnover flap from the index finger will not have a sufficient arc of rotation to cover this defect. A flag flap is best for coverage of defects involving the proximal phalanges or metacarpophalangeal joints of the fingers and should not be used for the thumb. A free flap should not be attempted when more simple options are available. A muscle flap is too bulky and would inhibit pinch strength, effectively limiting the use of the hand, which is unacceptable in a laborer.

Answer 178

The correct response is Option E. In this patient who has sustained a crush amputation of the distal third of the dominant thumb, the most appropriate management is coverage of the wound using a volar advancement, or Moberg, flap. This flap is most effective for coverage of thumb amputations that occur distal to the interphalangeal joint. It is comprised entirely of palmar thumb skin, providing an excellent color and tissue match. In addition, both neurovascular bundles are included for stable, sensate wound coverage. Split-thickness skin grafting alone over exposed bone will result in a painful thumb due to inadequate padding. A full-thickness skin graft provides a poor skin match. Sensory recovery is diminished with the use of this type of graft. The cross-finger flap should not be used in construction workers or other patients who require good hand function following repair. In addition, a large donor site defect would result. A thenar flap, which is based on the thenar eminence, is used to cover adjacent defects and cannot be used for the thumb.

Answer 179

The correct response is E In this patient who has findings consistent with hypothenar hammer syndrome, or thrombosis of the ulnar artery in Guyon's canal, the most appropriate next step in diagnosis is angiography of the upper extremity. Hypothenar hammer syndrome is characterized by pain in the region of the hook of the hamate bone as well as paresthesias and a decrease in digital temperature in the ring and little fingers. Because this condition is caused by repetitive trauma, it is often seen in carpenters who use the hypothenar eminence as a hammer-type device during their work. The diagnosis of hypothenar hammer syndrome can be confirmed with Doppler ultrasonography or angiography of the upper extremity. If findings on either test are positive, management should include surgical exploration of the ulnar artery and resection of the thrombosed segment. The inflammation characteristically seen around the thrombus in patients with hypothenar hammer syndrome has been theorized to result in sympathetic hyperstimulation and irritation of the ulnar nerve; as a result, some surgeons have advocated the use of thrombolytic therapy. Although reconstruction of the ulnar artery with a vein graft is controversial, most surgeons agree that grafting can be used to prevent cold intolerance in certain patients. If the distal ulnar artery pressure is less than 0.7 times the proximal ulnar artery pressure, vein grafting can be beneficial. Radiographs of the carpal tunnel can be performed to diagnose a fracture of the hook of the hamate bone, which is instability in patients with Raynaud's phenomenon.

Answer 180

The correct response is Option A. The central, lateral, and spiral cords each contribute to recurrent contracture of the PIP joint; the little finger is affected most frequently. The central cord develops from fascia between the neurovascular bundles and is continuous proximally with the pretendinous cord. It attaches distally to the tendon sheath over the middle phalanx. The lateral cord is adherent to the skin, while the spiral cord can occur as a continuation of the pretendinous cord or can arise at the musculotendinous junction of the intrinsic muscle. This cord straightens and courses less obliquely over time. The natatory cord passes across the palm at the level of the web spaces and attaches to each individual flexor tendon sheath. Contracture of this cord can contribute to contracture of the PIP joint. Cleland's ligaments are fascial structures located dorsal to the neurovascular bundle that help to hold the skin in position during flexion and extension of the finger. These structures are only an occasional cause of PIP joint contracture. The retrovascular cord most frequently causes contractures of the distal interphalangeal joint. This longitudinally oriented fascial cord lies dorsal to the neurovascular bundle and palmar to Cleland's ligament. Knuckle pads are a manifestation of joint contracture and not a cause themselves.

Answer 181

The correct response is Option C. This 43-year-old man has limited abduction of the ring and little fingers at the level of the metacarpophalangeal joints caused by Dupuytren's contracture of the natatory ligaments. These ligaments, which are found within the digital web spaces, primarily pass in a transverse manner but may run distally along the sides of the fingers to join with the lateral digital sheet. Patients with Dupuytren's contracture of the natatory ligaments have limited finger abduction and flexion contractures of the proximal interphalangeal joints. Although transverse fibers of the palmar aponeurosis are seen more proximally at the level of the metacarpal necks, they play no role in the Dupuytren's contractures. Cleland's ligaments, which originate from the phalanges and pass dorsal to the digital neurovascular bundle into the lateral digital sheet, do not contribute to Dupuytren's contractures. Grayson's ligaments are thin structures that arise from the flexor tendon sheath and travel volar to the digital neurovascular bundle into the lateral digital sheet. These ligaments are frequently involved in Dupuytren's contractures. The mechanism of action of both Cleland's and Grayson's ligaments is stabilization of the skin during finger motion. Most patients with Dupuytren's contractures have involvement of the pretendinous bands of the palmar aponeurosis. Progressive fibrosis and shortening of these bands results in the development of a pretendinous cord, which causes flexion contractures of the metacarpophalangeal joints in the disease state. This band continues distally into the fingers, where it divides into the radial and ulnar spiral bands. Although these bands ultimately contribute to the lateral digital sheet, they are not a cause of Dupuytren's contractures.

Answer 182

The correct response is Option C. This patient's wound is best covered with a Moberg advancement flap. This flap can be used to effectively preserve length in many patients who have palmar oblique amputations of the thumb. Harvest of the Moberg flap is possible because the thumb has a dual arterial supply. It is raised on its neurovascular pedicles and thus provides durable, sensate coverage of the pulp of the thumb. However, advancement greater than 1.5 cm is difficult; contractures of the interphalangeal joints can occur with the use of a Moberg flap. In addition, this flap should not be used in other digits because the digital arteries must be included with the flap. Vascular compromise is likely, resulting in dorsal skin necrosis. The V-Y flap is a useful variation of the Moberg flap. Dressing changes are most appropriate for small wounds (less than 10 ( 10 mm) without exposure of bone or tendon. Full-thickness skin grafts are appropriate for large avulsion injuries; these grafts will regain at least protective sensibility when employed. The neurovascular island flap is a sensate flap harvested from the ulnar side of the middle or ring finger and transferred to the thumb. Venous congestion and absence of cortical reorientation may be noted following flap transfer. Thenar flaps are used for amputations of the index and middle fingertips with exposed bone to preserve finger length; they cannot be used in the thumb. Postoperative stiffness of the proximal interphalangeal joint and painful donor site scarring may be associated.

Answer 183

The correct response is Option E. In this patient who has a Dupuytren's contracture primarily involving the metacarpophalangeal (MP) joint of the ring finger, the least appropriate management is static flexion splinting, which would only worsen the flexion contracture. Static extension splinting should be used instead following surgical treatment of flexion contractures. Collagenase injections have been used successfully in the treatment of Dupuytren's contracture. According to several studies, excellent results have been achieved in 90% of MP joint contractures and 60% of proximal interphalangeal joint contractures nine months after initiation of treatment. Continuous skeletal traction has been shown to provide only a temporary resolution of flexion contractures. This technique, which results in continuous elongation, should be followed by limited fasciectomy. Administration of triamcinolone and/or other corticosteroids has been shown to improve palmar nodules. Other modalities, such as administration of dimethyl sulfoxide (DMSO), vitamin E, or medications used in the treatment of gout, as well as physical therapy and ultrasonography, have no demonstrated effect in patients with Dupuytren's contractures.

Answer 184

The correct response is Option C. In this patient who has sustained an avulsion injury of the skin of the dominant thumb, the most appropriate management is coverage of the defect using a kite flap, a neurovascular flap harvested from the dorsal soft tissue of the proximal phalanx of the index finger. The vascular pedicle of this flap is the second dorsal metacarpal artery; two nerve branches, the superficial radial sensory nerve branch and dorsal proximal interphalangeal joint branch, can be used for digital nerve reconstruction (microneurorrhaphy). The kite flap can only be used if the paratenon has been preserved; in addition, skin grafting of the donor site must be performed following flap transfer. Dressing changes are best for defects smaller than 10 ( 10 mm without exposed vital structures (eg, bone, tendons, nerves). A 1-cm wound may require as long as six weeks to heal. Split-thickness skin grafts to the distal phalanx of the thumb cortex would not result in stable, durable, or sensate thumb padding. The Moberg advancement flap is appropriate for palmar oblique thumb amputations in order to preserve as much length as possible. However, because the flap cannot be advanced more than 1.5 cm, its use would not be practical in this patient. In addition, contractures of the interphalangeal joints are associated, and sensibility would be poor in a patient with absence of both digital nerves. The thenar flap is typically used for coverage of defects involving the index and middle fingers in which there is exposed bone in order to preserve much length as possible. Postoperative stiffness of the proximal interphalangeal joint and painful scarring are associated. The thenar flap cannot be used to cover thumb amputations.

Answer 185

The correct response is Option A. Arterial thrombosis of the hand occurs infrequently but can lead to significant loss of hand function. Treatment options depend on the history and clinical findings. Appropriate care almost always requires coordination with interventional radiologists. Doppler ultrasonography can be used to evaluate flow all the way out to the digital arteries. The lack of a biphasic signal suggests arterial occlusion but cannot document the area of occlusion. Another limitation of ultrasonography is operator expertise. Laser Doppler can be useful for monitoring local perfusion of flaps. CT angiography is often the first imaging done for patients with limb ischemia due to the faster scan times, but it cannot show much detail beyond the wrist and is rarely useful in visualizing the superficial arch or digital vessels. MR angiography (MRA) has the advantage of not requiring ionizing radiation or the use of contrast agents, but it is very time-consuming and requires significant expertise to get good images. Traditionally, spatial resolution limits of MRA limit the visualization of arteries 1.0 mm or less in diameter. Nonetheless, MRA may be indicated for patients with contraindications to CT angiography or catheter-based arteriography. Catheter-based arteriography is the gold standard for vascular imaging of the smaller vessels of the hand and may allow the interventionalist to treat with catheter-directed thrombolysis or percutaneous mechanical thrombectomy. Angiography also can evaluate the entire limb to rule out proximal sources of emboli and gives the surgeon the best road map if surgical intervention is decided on.

Answer 186

The correct response is Option D. This patient is experiencing a flare reaction following Dupuytren surgery and should be managed initially with anti-inflammatory medication. When counseling patients about postoperative complications following surgery for Dupuytren disease, flare reaction and complex regional pain syndrome (CRPS) should both be discussed. Flare reaction is disproportionate swelling, pain, and stiffness following surgery that usually appears after several weeks of otherwise uneventful healing. Management is supportive, with anti-inflammatory medications, stellate ganglion block, edema control, and neurologic medications. Incidence of flare reaction has been documented between 10 and 50%. This diagnosis has some overlap with CRPS type 1. Both diagnoses are poorly understood. CRPS is divided into two subtypes. CRPS type 1, formerly called reflex sympathetic dystrophy, is a chronic pain syndrome that develops without a defined nerve injury. CRPS type 2, formerly called causalgia, is a chronic pain syndrome that develops after a nerve injury. Clinically, however, the two subtypes appear the same. The timing of CRPS post injury can vary widely, from first symptoms immediately to weeks later. Unfortunately, CRPS has no defined pathognomonic marker. The diagnosis is associated with autonomic dysfunction and pain in a regional, rather than dermatomal or peripheral nerve, distribution. Diagnosis is based on the Budapest Criteria, which has high sensitivity for CRPS and greater specificity than the International Association for the Study of Pain criteria. The Budapest Criteria are: * Continued pain that is disproportionate to any inciting event * Patient must report one symptom in three of the following four categories: * Sensory: allodynia or hyperalgesia * Vasomotor: temperature asymmetry, skin color changes * Sudomotor: edema, changes in sweating * Motor: decreased range of motion, motor dysfunction, changes in hair or nail growth * Must display one sign at the time of evaluation in at least two of the following categories: * Sensory: evidence of hyperalgesia and allodynia * Vasomotor: evidence of temperature asymmetry or skin color changes * Sudomotor: evidence of edema or swelling * Motor: motor weakness/dysfunction * No other diagnosis explains the patients signs or symptoms. A recent large claims review found a rate of CRPS following Dupuytren surgery at 0.31%. Significant predictors included female sex, southern region, long-term disability status, palmar fasciectomy with release of one or more than one digit, or multiple concurrent procedures for Dupuytren contracture. Previously, investigators recommended triple-phase bone scanning to make the diagnosis of CRPS. However, they have insufficient sensitivity and specificity and are not a prerequisite for the diagnosis. Electromyography has shown some use for diagnosing CRPS in specific patient populations. Approximately 11 to 36% of patients with CRPS demonstrate myoclonus, and this may be characterized as different from other types of myoclonus by using electromyography. The limited number of patients who present with CRPS and myoclonus limits the sensitivity of electromyography as a diagnostic tool. Ultrasonography has been used to characterize differences in muscle tissue in CRPS patients. CRPS patients have significant myoglobular distortion, while muscles affected by chronic neuropathic pain are structurally normal. However, no studies have validated ultrasonography as a useful diagnostic modality. The clinical presentation is suspicious for flare or CRPS. Fasciotomy is not indicated.

Answer 187

The correct response is Option E. The patient presents with classic primary Raynaud findings. While relatively common and not associated with underlying systemic disease, the symptoms of primary Raynaud disease can have a detrimental effect on quality of life. Such patients have overactive smooth muscle alpha-2 adrenoceptors, leading to amplification of sympathetic vasoconstriction in response to normal norepinephrine release at decreased temperatures. Options for treatment include chemical sympathectomy with botulinum toxin type A injections. Botulinum toxin type A can prevent sympathetic vasoconstriction seen in patients with Raynaud disease. Endothelin-1 is found circulating in higher levels in patients with secondary Raynaud phenomenon, which is seen most commonly in patients with connective tissue disorders but can also be found in patients with obstructive vascular disease, certain drug exposures, viral infections, and occupational exposures. Antiphospholipid antibodies may be seen in connective tissue disorder and are associated with increased risk for thrombosis. Delta receptors, also called delta opioid receptors, are found in the brain, and their activation leads to analgesia. They are not implicated in Raynaud phenomenon.

Answer 188

The correct response is Option E. The patient has signs and symptoms consistent with hypothenar hammer syndrome. Hypothenar hammer syndrome results from repeated trauma to the ulnar artery at the hook of hamate bone. This can lead to ulnar artery aneurysm, with possible formation of a palpable mass, thrombosis, and distal embolization to the fingers. Patients may also experience pain, cyanosis, pallor, coolness, and recurrent episodes of vasospasm. The condition is more common in men than women, typically occurs in the fourth and fifth decade of life, and is more likely to affect the dominant hand in certain professions like carpenters, builders, and other physical laborers working with hammers and vibrating tools. Angioplasty and stenting is typically not done in the hand. Catheter-directed thrombolysis can address intermittent clots in the acute setting but would not resolve the underlying problem of aneurysmal dilation. Digital sympathectomy has been suggested to alleviate vasospastic conditions, but it would not be adequate to treat the embolic consequences of ulnar artery aneurysm in hypothenar hammer syndrome. Ligation of the ulnar artery alone is a form of treatment for hypothenar hammer syndrome, but it is typically not done unless there is better blood flow (digital brachial index greater than 0.7). In this patient with a digital brachial index of 0.6, the relative ischemia would suggest restoration of ulnar artery flow with repair or graft instead of ligation alone. Mechanical compression and thrombin injection is a method of treatment for pseudoaneurysms, but it would not be indicated in the management of hypothenar hammer syndrome.

Answer 189

The correct response is Option D. Skeletal stabilization should be performed first when time allows as the manipulation required may disrupt the repair of the other structures if they are performed first (such as vessels and nerves). Due to the presence of skeletal muscle in the forearm and upper arm, which has limited tolerance for ischemia, the order of management of the injuries is different than in digital replantation or revascularization. Early establishment of distal perfusion is important and can either be achieved by direct vascular repair, vein grafting, or placement of a temporary shunt. Shunting may be necessary first if the patient is presenting in delayed fashion, as establishing perfusion is critical, but skeletal stabilization requires manipulation and may interrupt the arterial repair. If temporary perfusion is established and skeletal stabilization is complete, definitive vascular repair can be performed subsequently in conjunction with tendon and nerve repair, as dictated by the character of the wound. However, for this patient presenting early (2 hours), skeletal stabilization should be completed first, followed by reestablishing perfusion. Consideration should always be given to decompressive fasciotomy after major revascularization procedures of the upper extremity.

Answer 190

The correct response is Option B. In a study of 1807 patients presenting to Boston Children's Hospital between 2005 and 2011 with digital injuries, 59% were male, the mean age at time of injury was 8 years, and the most common mechanism of injury was crush in a door or window (46%). This mechanism was distantly followed by laceration, sports, machine, and fall. In another study of digital amputations in patients aged 19 years and younger, doors accounted for nearly 60% of all cases in children under 10 years old and 15% of cases in the 10- to 19-year-old age group. Other notable causes included chairs or stools and bicycle components. Over age 20 years, amputations are predominantly caused by saws in over 55% of cases.

Answer 191

The correct response is Option A. There is wide variety to the arterial blood supply of the trimmed great toe flap. The first dorsal metatarsal artery is dominant in approximately 70% of cases, the first plantar metatarsal artery is dominant in 20%, and the two are equivalent in 10%. Within those categories, there is variety in the course and location of the artery. Gilbert classified the anatomic varieties of the first dorsal metatarsal artery into type I superficial, type II deep, and type III fine branch/absent. More recently, Gu et al presented a more detailed first dorsal metatarsal artery classification system with clinical applications. This classification system has three components: location, size, and branching pattern. The most common variant was found to be an intramuscular, 1- to 1.5-mm, ramifying type. The variant with the highest rate of flap failure was an inframuscular, less than 1 mm, fine branch type. The lateral dorsal digital artery can be used for smaller flaps, such as for distal digital reconstruction. The medial plantar digital artery flap is a pedicle that can be used for trimmed second toe flaps.

Answer 192

The correct response is Option C. "White clot" is comprised of platelets and can lead to vascular complications in microsurgical anastomosis. This is typically encountered in more damaged or abnormal vessels and can also be seen due to technical errors in the anastomosis. While thrombolytic agents (such as tissue plasminogen activator) can be used, they have been shown to not be as effective with white clot and would not be administered systemically. In arterial anastomosis, local heparin use has been shown to be more effective than systemic heparin. Management of white clot in this setting is ultimately a technical solution, in that removing the damaged segment of artery and vein grafting would have a higher degree of success. Given that the clot is comprised of platelets, white clot is better treated by antiplatelet pharmacologic agents than anticoagulation agents. Because the thumb is a critical digit, another attempt at salvage outside of the zone of injury is warranted.

Answer 193

The correct response is Option C. The most appropriate management of this patient is active rewarming (eg, warmed intravenous fluids, warming blankets) and observation. He has moderate hypothermia, evidenced by confusion, shivering, and tachycardia. He likely has some form of frostbite in his fingers; however, it is too soon to determine what treatment is required for this condition. First-degree frostbite affects the outer skin only, second-degree frostbite affects the skin in full thickness but heals in most cases, and third-degree frostbite affects the deeper structures and often requires amputation. Passive rewarming (eg, blankets, warm room) is appropriate for mild hypothermia only. Amputations are not indicated this early in this patients course, as indicated previously. Digital escharotomy might be indicated for a severe hand burn, but it has no role for this patient with hypothermia and an undetermined degree of frostbite.

Answer 194

E Digital amputations represent a common presenting injury for the hand surgeon to manage. Replantation is an option for treating amputation injuries, and criteria for patient selection has been proposed in the literature based on outcomes. There are many considerations including factors related to the patient, hospital, and treating surgeon. Many reports have measured the success of replantation at high-volume centers versus medium- and low-volume centers, demonstrating a greater success rate at high-volume centers (Brown et al, Hsu et al). This is important in considering referral to a specialized center when encountering these injuries. While single-digit involvement can at times be a relative contraindication to replantation depending on the digit (eg, border digit), the involvement of a single digit is not associated with failure of replantation (Pet et al). The mechanism of injury can play a major role in success, with sharp injuries resulting in less tissue damage and greater success rates compared with crush and burn injuries (Pet et al). The use of vein grafts has been demonstrated to not decrease the likelihood of success and in many situations is a necessary step in completing a successful replantation (Sebastin et al). Digital ischemia time prior to revascularization has been evaluated and shown to be successful within the time frame of this scenario (Sebastin et al).