Wrist 01-22, 24 Flashcards

Question

A 36-year-old man undergoes rehabilitation following scapholunate ligament repair. Initial range of motion in therapy is planned to allow wrist movement while minimizing the movement between the scaphoid and lunate bones. Which of the following wrist movements is most likely to achieve this goal? A) Neutral wrist extension to neutral wrist flexion B) Radial deviation in extension to radial deviation in flexion C) Radial deviation in extension to ulnar deviation in flexion D) Ulnar deviation in extension to radial deviation in flexion E) Ulnar deviation in extension to ulnar deviation in flexion

Answer 1

The correct response is Option C. The most appropriate motion is from radial deviation in extension to ulnar deviation in flexion. The dart-thrower’s motion, moving from radial deviation in extension to ulnar deviation in flexion, minimizes the movement between the scaphoid and lunate. Studies have shown that during movement in this axis, from radial deviation and extension to ulnar deviation and flexion, the bones of the proximal carpal row (scaphoid, lunate, triquetrum), remain practically stationary, and motion occurs primarily through the midcarpal joint. As a result, this is felt to be the primary mechanical axis of movement in the wrist. Rehabilitation with movement in the dart-thrower’s axis will limit movement between the bones of the proximal carpal row and allow wrist range of motion while minimizing stress on a scapholunate repair. Simulation of radioscapholunate fusion results in preservation of the dart-thrower’s motion, confirming this concept. The remaining motions listed result in greater intercarpal movement of the proximal row.

Answer 2

The correct response is Option C. The Eaton stress view is done with the radial borders of the thumb distal phalanges pressed together. It is a posteroanterior view and assesses laxity of the basal joint as demonstrated by subluxation of the thumb metacarpal on the trapezium. The Brewerton view is taken with the fingers flat on the x-ray plate with the metacarpophalangeal joints flexed 65 degrees beam angled from a point 15 degrees to the ulnar side of the hand. It shows the metacarpal head and is useful for demonstrating degenerative disease or occult fractures. Bett (or Gedda) view is characterized as a true lateral view of the trapeziometacarpal joint, perpendicular to the plane of the hand. It is performed as a posteroanterior view, with the hand pronated 30 degrees and the axis of the imaging tube angled 25 degrees distally. The view isolates the trapeziometacarpal joint and is useful for evaluating metacarpal base fractures (Bennett’s fracture). Roberts view is done with the wrist hyper-pronated and the dorsum of the thumb flat on the plate with an AP view. It is used to evaluate degeneration of the trapeziometacarpal joint but does not show subluxation as the stress view does.

Answer 3

The correct response is Option E. The scaphoid oblique view is a posteroanterior (PA) view with the wrist in ulnar deviation and the beam angled 20 degrees distal to proximal. This view often will show scaphoid fractures not seen on standard PA, oblique, or lateral views. The other views would not extend the scaphoid and the scaphoid would not be seen as clearly.

Answer 4

The correct response is Option A. Scaphotrapeziotrapezoid (STT) arthritis can often be misdiagnosed on initial presentation as basal joint arthritis. The keys to differentiating the two sites of pain include physical examination, which shows tenderness more proximal than the basal joint and absence of pain with a grind maneuver, coupled with imaging showing osteoarthritic degeneration at the STT rather than the trapeziometacarpal level. Treatment for the arthritic pain can consist of resection arthroplasty or arthrodesis. Both techniques can provide good relief of symptoms. Resection arthroplasty often is used when the scapho-trapezoid articulation is relatively preserved. Regardless of technique chosen, the surgeon should address both the scapho-trapezial and the scapho-trapezoid joints during the procedure. Release of the first dorsal compartment would address de Quervain tenosynovitis, which could present with pain over the anatomic snuffbox. On examination, however, the patient would typically demonstrate pain with the "resisted Hitchhiker" maneuver (resisted extensor pollicis brevis function at the metacarpophalangeal level). Given the negative findings on examination and the STT arthritis noted on imaging, this patient would not likely respond to treatment directed at the first dorsal compartment. Second dorsal compartment tenosynovitis can present with distal forearm and wrist pain. The location of the pain is typically more proximal in the forearm and localized to the intersection between the muscle bellies of the first compartment tendons and the radial wrist extensors. This patient's pain is localized to the STT region rather than the second dorsal compartment. Hemiresection of the distal trapezium and tendon interposition has been used successfully in the management of trapezio-metacarpal arthritis (basal joint arthritis). In this patient, the location of the pain, absence of pain with a "grinding" type maneuver, and the imaging showing preservation of the basal joint argue against directing treatment at the basal joint itself. For the same reasons that hemiresection of the distal trapezium is a poor choice for this patient, arthrodesis of the basal joint addresses the wrong site of arthritis. X-ray study and physical examination both indicate STT arthritis as the etiology of the patient's pain.

Answer 5

The correct response is Option B. The patient described may have a scaphoid fracture that is not apparent on initial x-ray studies. Prudent management involves placement of a thumb spica splint until definitive diagnosis can be made. Repeating x-ray studies in 2 weeks or obtaining further radiologic studies, such as CT scans, can make the definitive diagnosis. Casting would be suboptimal in an acute injury such as this because soft-tissue swelling can cause constriction. Surgical exploration is not warranted at this time. A wrist-control, sugar-tong, or ulnar gutter splint would not adequately immobilize the scaphoid, and therefore, would not be adequate management. Acute scaphoid fractures can often be missed on initial x-ray studies, with reported sensitivities ranging from 84 to 98%. When clinical suspicion of a scaphoid fracture is high and plain films are negative, the traditional recommendation is for these patients to be immobilized in a thumb spica splint or cast with repeat x-ray studies after about 2 weeks. Even on the repeated x-ray study after 10 to 14 days propagated by many clinicians in cases of occult fracture, a scaphoid fracture is often missed since the additional sensitivity is low, although in a case of sclerosis, an x-ray study could confirm the suspected diagnosis. Further studies that may confirm the diagnosis include CT scan, MRI, and bone scan.

Answer 6

The correct response is Option B. The descending genicular artery is the arterial pedicle for the medial femoral condyle free vascularized osseous corticoperiosteal free flap, or free vascularized bone graft. Scaphoid nonunions with a humpback deformity, carpal collapse, and proximal pole osteonecrosis are difficult to treat. Vascularized bone grafts have been shown to have nearly 2× the union rate of traditional nonvascularized bone grafts. Vascularized corticocancellous bone has the potential to revascularize necrotic bone and can provide structural support for fractures with loss of height of the scaphoid. Studies have shown superior union rates for the medial femoral condyle vascularized bone graft versus pedicled grafts from the distal radius. Anatomical studies show no clinical loss of stability of the femur after flap harvest. The peroneal artery is the blood supply of the fibular osseous or osteocutaneous free flap. It is generally reserved for head and neck reconstruction and larger defects of the extremities. The descending branch of the lateral femoral circumflex artery supplies the anterolateral thigh free flap. The dorsalis pedis artery supplies the dorsalis pedis fasciocutaneous flap. The medial sural artery and its perforators supply the medial gastrocnemius muscle, and musculocutaneous and fasciocutaneous flaps. All of these flaps are used for soft-tissue defects alone and are not appropriate for reconstruction of bony defects.

Answer 7

The correct response is Option B. This patient has dynamic scapholunate instability. These injuries can be difficult to diagnose and require a high index of suspicion. A normal x-ray study at 12 weeks in the setting of these clinical findings suggests there is a disruption of the scapholunate interosseous ligament (SLIL) that is symptomatic only with mechanical loading. The SLIL is the primary stabilizer of the scapholunate joint, but it is surrounded by multiple secondary stabilizers consisting of the extrinsic wrist ligaments. Normal kinematic motion of the proximal carpal row is controlled by the tough interosseous ligaments. The dorsal component of the SLIL is the primary restraint to distraction, torsion, and translational forces. Disruption of the dorsal SLIL alone will result in changes in wrist mechanics, but the presence of the intact secondary stabilizing ligaments will prevent changes seen on a normal static x-ray study, such as scapholunate dissociation or an increased scapholunate angle. Stress view x-ray studies, such as the clenched-pencil view, should be obtained when dynamic instability is suspected in the setting of a normal static x-ray study series. These results can be compared with the contralateral normal side. Non-contrast MRI is an advanced imaging modality averaging 71% sensitivity, 88% specificity, and 84% accuracy for SLIL tears. There is improved accuracy with 3.0T MRI machines. Wrist arthroscopy is the gold standard for diagnosis and can be combined with therapeutic procedures such as debridement or thermal shrinkage. An occult scaphoid fracture should be visible at 12 weeks following the injury. Bone resorption at the fracture site makes the fracture line generally visible within 14 days. If suspicion remains for an occult scaphoid fracture at 2 weeks, additional imaging such as MRI or CT scan is indicated. At 3 months following the injury, any fracture present should be visible and treated as a non-union of the scaphoid. De Quervain tenosynovitis is defined as tendinitis of the first dorsal extensor compartment. This condition generally presents with pain and tenderness over the radial styloid with a positive Finkelstein test. Tenderness of the carpal bones and carpal bone instability such as a painful “clunk” would not be present. The condition is most associated with repetitive use and not acute trauma. Kienböck disease involves collapse of the lunate due to vascular insufficiency and avascular necrosis. Etiology is unknown but may involve a combination of anatomic factors and trauma. Early symptoms are similar to a wrist sprain but involve more global wrist pain, loss of dorsiflexion, and tenderness of the dorsal wrist over the lunate. Early stage I disease can have normal x-ray studies but will often show signs of a lunate fracture. Later stage disease shows sclerosis and ultimately fracture or collapse of the lunate. Flexor carpi radialis (FCR) tendinitis is not a common diagnosis. It presents with wrist pain, crepitus, and point tenderness over the FCR at the wrist flexion crease with flexion and radial deviation. Although it is a cause of radial-sided wrist pain, findings of carpal bone instability on examination are not present.

Answer 8

The correct response is Option D. The imaging study that is most sensitive and specific for detecting an acute scaphoid fracture is MRI. Many authors have written about the best secondary imaging study for scaphoid fractures not evident on standard x-ray studies. MRI is the best test considering both sensitivity and specificity, followed by CT scan. The majority of the published data shows bone scan to be the most sensitive but less specific than MRI or CT scan. Ultrasonography is used for evaluation of long bone fractures but is not yet indicated for evaluation of carpal bone fractures.

Answer 9

The correct response is Option A. The capitolunate articulation should be intact in order to perform proximal row carpectomy. The patient described has a chronic scapholunate tear, which if left untreated, can lead to the consequences of scapholunate advanced collapse (SLAC) wrist. With ongoing progression, degenerative wrist arthritis and pain result. Arthritis occurs in a predictable sequence, initially at the radioscaphoid joint, followed by the scaphocapitate joint and the capitolunate joint. The radiolunate joint is typically spared until advanced stages. Proximal row carpectomy is a salvage wrist procedure that can be used in some cases of SLAC wrist. The proximal carpal bones of the wrist (scaphoid, lunate, and triquetral) are removed, and the capitate head is allowed to rest in the lunate fossa of the radius. In order for this procedure to be successful, the capitolunate joint should be free of arthritis. The patient should have preservation of cartilage on the capitate head and the lunate fossa of the radius, as this forms the new articulation of the wrist.

Answer 10

The correct response is Option E. The triquetral is the second most commonly fractured carpal bone. Most triquetral fractures are dorsal ridge fractures that appear as avulsion fractures on lateral view wrist x-ray studies. The most common carpal bone fracture incidences in order of frequency are scaphoid, triquetral, trapezium, lunate, and hamate.

Answer 11

The correct response is Option D. All the other answers are incorrect due to incorrect sequence of force transmission across the wrist. Furthermore B and E are wrong due to incorrect mechanism, as well. Wagner and Mayfield conducted classic studies on carpal dynamics and anatomy to determine the progression of stresses across the wrist in severe hyperextension injuries. They determined that there is a reliable and predictable pattern to these injuries, which is described as Progressive Perilunate Instability (PLI). There are four stages of PLI, corresponding to the degree of stress applied in the injury. The mildest form is the isolated scapholunate dissociation: PLI stage 1. As the forces continue in an ulnar and distal direction, the distal row and scaphoid progress dorsally, and the capitate separates from the lunate: PLI stage 2. As the force continues in an ulnar direction, the lunotriquetral ligaments separate, and if the lunate is still in place, this is the full Midcarpal Dislocation: PLI stage 3. Finally, in the most severe cases, the dorsally dislocated capitate will dislodge the lunate and push it volarly, creating the true lunate dislocation: PLI stage 4.

Answer 12

The correct response is Option C. Treatment of a scaphoid malunion or “humpback” nonunion deformity by means of an opening interposition wedge bone graft is indicated when the lateral intrascaphoid angle is greater than 45 degrees. The intrascaphoid angle is determined by drawing a line tangent to the dorsal cortex of the distal fragment and the palmar cortex of the proximal fragment. Normally, this angle is 30 to 40 degrees. Amadio and coworkers reported on 45 patients with 46 scaphoid fractures greater than 6 months after healing. There were good clinical outcomes in 83% of those with intrascaphoid angles less than 35 degrees, and posttraumatic arthritis in 22%. In contrast, in those with greater than 45 degrees of lateral intrascaphoid angulation, only 27% had good outcome, and 54% developed posttraumatic arthritis. Nakamura and colleagues performed volar wedge bone grafting on seven symptomatic patients with scaphoid malunion, and all improved their symptoms.

Answer 13

The correct response is Option E. Thumb basilar joint arthritis is a common debilitating problem. The prevalence in postmenopausal women has been estimated at 33%, although many patients with radiographic evidence of arthritis remain asymptomatic. It more often occurs in the dominant hand. The extent of arthritis and joint deformity dictates the best treatment choice. The most widely used classification is that of Eaton and is based on radiographic findings. Stage I has normal joint contours but possible joint widening due to effusion. Although most patients respond to splinting, anti-inflammatory medications, trapezial hemi-resection, and metacarpal osteotomy have been advocated in very symptomatic patients. Stage II shows slight trapeziometacarpal (TM) joint narrowing and minimal sclerosis of the articular surface. The indications for operative treatment are more concrete, and surgical options are largely the same as Stage I, with the addition of CMC fusion as an option in a laborer. Stage III presents as TM joint narrowing with cystic or sclerotic changes in the articular surface. There is variable dorsal subluxation of the TM joint, and adduction contracture may occur. There can be early signs of scaphotrapezial (ST) joint arthritis. If the ST joint is in relatively good condition, some authors still advocate trapezial-sparing procedures such as hemi-resection. Nevertheless, most advocate trapeziectomy with or without ligament reconstruction/tendon interposition (LRTI). There is some evidence that ligament reconstruction preserves the joint space better than no reconstruction, but provides no better clinical outcome and has a higher complication rate. Trapeziectomy ± LRTI provides excellent pain relief and improved function, especially in lower demand patients. In Stage IV, the TM and ST joints are completely destroyed. In these patients, LRTI is the preferred treatment. Some authors report good early results in selected patients with implant arthroplasty; however, there is a moderately high rate (up to 40%) of instability, dislocation, and implant breakage. The use of silicone as a spacer has fallen into disuse due to the risk of chronic tissue inflammation and resultant bone resorption.

Answer 14

The correct response is Option A. Specialized views of the wrist can provide better information regarding bony relationships and fractures, in addition to standard anteroposterior, lateral, and oblique films. There are many different specialized views that the plastic surgeon should be familiar with. Among these are the scaphoid, stress, and carpal tunnel views. The carpal tunnel view is a hyperextended wrist view displaying the carpal bone to carpal tunnel relationships. This view allows visualization of the hook of the hamate and the pisotriquetral joint, as well as the palmar surfaces of the trapezium, pisiform, and triquetrum.

Answer 15

The correct response is Option D. The patient described has scapholunate separation that results not only in widening of the gap between the scaphoid and the lunate, as depicted in the x-ray study shown (Terry-Thomas sign), but also in flexion of the scaphoid. This is seen on the anteroposterior x-ray study as a ?ring sign? as a result of the distal pole of the scaphoid moving relatively closer to the proximal scaphoid cortex and being viewed end-on. Carpal bone malalignment is also determined by angles on lateral x-ray studies. As the scaphoid flexes progressively, the lunate (still tethered to the triquetrum) goes into an extension dorsal intercalated segment instability deformity. In a patient with rotary subluxation at the scaphoid, the scapholunate angle is expected to be increased on lateral x-ray study. Normal values range from 30 to 60 degrees. Angles greater than 80 degrees are considered a definite indication of scapholunate dissociation.

Answer 16

The correct response is Option A. The mechanism of injury and the anterior-posterior x-ray study in the scenario described suggest dissociation between the scaphoid and lunate bones. This injury can result in a dorsal intercalated segmental instability (DISI), wherein the scaphoid bone loses the support of the scapholunate ligament and most commonly tips into volar or palmar flexion. In this scenario, the lunate then tips into dorsiflexion by the same mechanism; therefore, dorsiflexion of the lunate bone is correct. This also eliminates dorsiflexion of the scaphoid bone. A dissociation of the lunate and triquetral bones causes the opposite forces, and the lunate tips into volar flexion, eliminating volar flexion of the lunate bone. When the scaphoid and lunate bones dissociate, they can be expected to tip in opposite directions through the same forces, eliminating volar flexion of the lunate and scaphoid bones and dorsiflexion of the lunate and scaphoid bones. This would be a volar intercalated segmental instability (VISI).

Answer 17

The correct response is Option C. Perilunate dislocation is the most common form of carpal dislocation. There is disruption between the ligamentous connections of the lunate and other carpal bones and radius. In the scenario described, rupture of the scapholunate and lunotriquetral ligaments is the most likely cause of the dislocation. These ligaments are usually repaired, followed by open reduction and internal fixation. The dorsal intercarpal, dorsal radiotriquetral, radioscaphocapitate, and ulnotriquetral ligaments are not appropriate choices because they do not connect to the lunate.

Answer 18

The correct response is Option C. Polyurethaneurea (Artelon) implants typically biodegrade by hydrolysis and are described as causing minimal giant cell and foreign body reaction. Although long-term studies are still pending, they currently appear to be the best biomaterial for this application. The use of silicone trapezial implants was, at one time, a common procedure, but the long-term results of silicone arthroplasty wear and deformation led to multinucleated giant cell reactions with silicone granulomas and synovitis. This resulted in about a 25% failure rate with this modality. Similarly, a study by Greenberg, et al, showed an incidence of 80% osteolysis and a high failure rate with GORE-TEX implants. A biopsy specimen of one retrieved implant showed giant cell reactions. Marlex implants also showed foreign body reactions and synovitis. A study by Belcher, et al, on Permacol implants was terminated prematurely because of adverse reactions to the implant in 6 of 13 patients, with significant pain and evidence of multinucleated giant cells.

Answer 19

The correct response is Option C. Perilunate dislocations are relatively uncommon injuries that typically follow high-energy impact to the wrist. The pattern of injury traverses both the greater and lesser carpal arcs, disrupting the lunotriquetral ligament and either the scapholunate ligament or the body of the scaphoid (trans-scaphoid, perilunate dislocation). Although controversy surrounding the need for operative intervention existed in the past, poor long-term outcomes from closed reduction alone have showed the importance of early restoration of carpal alignment with repair of the injured ligaments. In the setting of trans-scaphoid, perilunate dislocation, this would include rigid internal fixation of the scaphoid. Application of finger traps and placement in traction may assist in reduction of the dislocated lunate but will not, by itself, reduce the lunate and remove the need for internal fixation and repair of the injured ligaments. Proximal row carpectomy and wrist function play a role in long-term salvage of the painful wrist following perilunate dislocations. Only in rare circumstances, such as nonreconstructible fractures of the proximal row bones, should acute proximal row carpectomy be considered. Splinting of the wrist in extension often provides relief in the setting of idiopathic carpal tunnel syndrome; however, in the setting of lunate dislocation, the presence of the lunate in the carpal tunnel necessitates reduction of the lunate for relief of symptoms.

Answer 20

The correct response is Option C. The scenario described demonstrates clinical features of the hypothenar hammer syndrome or aneurysm of the ulnar artery in the palm. The perfusion of the small and ring fingers is maintained with circulation through the superficial palmar arch. Thrombus, which accumulates within the aneurysm, showers distally creating embolic infarctions of the digits. Ligation of the artery without reconstruction is acceptable given collateral blood flow to the small and ring fingers. Ligation prevents further release of emboli from the aneurysm and can reduce associated vasospasm. This may improve distal digit perfusion and help in healing of areas of ulceration. In cases where there is evidence of inadequate digit perfusion, arterial reconstruction is indicated. Injection of thrombotic agents into the ulnar artery carries the risk of thrombosis of distal arteries and digital ischemia. The presence of the aneurysm suggests against vasospasm as the primary cause of ulceration. Therefore, digital sympathectomy and administration of antivasospastic medications, such as nifedipine, do not address the cause of the patient €™s problem. Anticoagulation may reduce the number of emboli but would not eliminate the aneurysm. The thrombi from the aneurysm create distal occlusion and necrosis.

Answer 21

The correct response is Option E. The triquetrum is the second-most commonly fractured carpal bone. Most triquetrum fractures are dorsal ridge fractures that appear as avulsion fractures on lateral view radiographs of the wrist. Pisiform, lunate, and capitate bones fracture less often than the triquetrum. The scaphoid is the most commonly fractured carpal bone. Scaphoid fractures comprise 70% of all carpal fractures, with triquetral at 14%. The isolated incidence of other carpal bone fractures is 0.2% to 5%.

Answer 22

The correct response is Option A. The patient described has a closed right dorsal perilunate, transscaphoid, transulnar styloid fracture-dislocation. In the scenario described, with no immediate operating room availability and with worsening pain and numbness, the most appropriate treatment is closed reduction followed by splinting, which can be performed in the emergency department under conscious sedation. When an operating room becomes available, the injuries to ligament and bone can be open repaired or reconstructed. The critical element is reduction to alleviate the numbness and pain. Splinting follows successful reduction. None of the other options listed addresses correction of the dislocation. The injection of corticosteroid, arthrogram, and MRI are not required for operative management. Postoperative radiographs are shown.

Answer 23

The correct response is Option A. Compartment syndrome occurs when the tissue pressure within a limited space results in decreased tissue blood flow, oxygenation, and function. It is primarily a clinical diagnosis based on muscle and nerve ischemia. The hallmark of muscle ischemia is pain, which is persistent, progressive, and unrelieved by immobilization. Accentuation of pain with passive muscle stretching is the most reliable clinical test for making the diagnosis of compartment syndrome. Diminished sensibility is the second most important finding, indicating ischemia of the nerve as it passes through the affected compartment. Weakness is the third most important finding, especially when progressive. Palpation of the forearm compartments for tenderness and tenseness associated with the above signs should confirm the diagnosis. Commonly held pressure thresholds for fasciotomies are as follows: (1) in normotensive patients with positive clinical findings and intracompartment pressures greater than 30 mmHg for an unknown time or a duration believed to be less than eight hours, (2) in uncooperative or unconscious patients with compartment pressures greater than 30 mmHg for less than eight to 10 hours, and (3) in hypotensive patients when compartment pressures are 20 mmHg below diastolic blood pressure for less than eight to 10 hours. If it is believed that a patient has compartment syndrome based on clinical evaluation, regardless of the compartment pressures, a fasciotomy should be performed.

Answer 24

The correct response is Option E. The scenario described is a case of a delayed presentation of compartment syndrome. This presentation could result from a prolonged delay to reduction of a fracture that causes compression of the brachial artery, bleeding into fascial compartments, or a cast that is too tight. Delays in recognition of compartment syndrome result in muscle necrosis and the development of Volkmann contracture. The extent of the injury is determined by the mechanism of injury and the involvement of certain muscle compartments. Milder injuries affect the deep flexor compartments. More severe injuries affect the superficial flexor and extensor compartments and hand-intrinsic muscles. In the absence of deep space infection or distal ischemia, acute management involves the maintenance of supple joints with physical therapy and dynamic splinting. Reconstruction is performed once the tissues have stabilized. At the time of reconstruction, debridement of fibrotic tissue and neurolysis of the median and ulnar nerves are performed. Restoration of motion is accomplished through muscle slide, tendon transfers, and functional free muscle flaps. Four weeks after the injury, muscle necrosis has occurred and the contracture established. Fasciotomies and debridement in this period will make wound care more complex and increase the risk of infection. Some surgeons recommend this intervention for treatment in the late acute phase (2 €“10 days). Intravenous antibiotics would not be indicated in the absence of infection. Electromyography and nerve conduction studies are not appropriate because, although nerve injury can occur as a consequence of treatment of trauma or fracture, isolated nerve injury is not consistent with the clinical scenario described.

Answer 25

The correct response is Option E. Split-thickness skin grafts allow for large defects to be covered with skin that will contract with time. In fasciotomy defects following crush injuries, the extremity remains swollen for an extended time. As the swelling subsides, the split graft will contract. A full-thickness graft would not contract as well and would require a large donor site defect for this sizable area. Burying the forearm in an abdominal flap would yield a very bulky forearm and prevent physical therapy to the extremity while it is attached to the abdomen. A free flap is unnecessary, as there are no exposed structures (nerve, tendon, or bone) that require vascularized coverage. Under different circumstances, the scapular free flap provides a fairly large surface area of thin skin. The defect in the patient described is too large for intraoperative skin expansion and would put the underlying structures under pressure.

Answer 26

The correct response is Option E. The patient described has a case of impending compartment syndrome. The cardinal signs of evolving compartment syndrome are $ pain disproportionate to the injury $ palpably swollen compartments $ pain on passive stretching of the involved muscles $ diminished perception of simple touch $ decreased strength of the involved muscles $ hypesthesia or anesthesia A significant amount of forearm hemorrhaging can occur after avulsion injuries such as the one shown in the photograph. The surgeon must suspect compartment syndrome and proceed to surgery. None of the other treatment modality options listed are adequate in light of the severity of symptoms.

Answer 27

The correct response is Option B. Osteoarthritis of the carpometacarpal joint of the thumb is frequently seen by hand surgeons and often requires surgical reconstruction. Classical teaching by Eaton and Littler supports the technique of ligament reconstruction and tendon interposition arthroplasty. Reported results using this technique are very good, with more than 80% relief of symptoms. Several authors have recently reported that trapezium excision and cast immobilization may be just as effective in relieving symptoms as the more extensive placement of a soft €‘tissue spacer and ligament reconstruction. Although the other management options are effective, they are not as essential to successful outcome as the simple act of cast or splint immobilization for four to six weeks in the postoperative period.

Answer 28

The correct response is Option A. The trapeziometacarpal (TM) joint is frequently affected with osteoarthritis. Arthritis of the trapezium can affect five articulations: TM, trapezium €‘second metacarpal, trapezium €‘trapezoid, scaphotrapezial, and scaphotrapezoidal. When all of these surfaces are involved, the condition is called pantrapezial arthritis. This complex of trapezial articulations is referred to as the basal joint of the thumb. The key to the scenario described is twofold. The first important fact is that radiographic staging may not relate to symptoms. The second important tenet is that conservative nonoperative therapy such as splinting and injection of corticosteroids should be tried first. If conservative therapy is unsuccessful, then arthroplasty is indicated. The patient described has pantrapezial arthritis in the right basilar joint, but he has no symptoms. Therefore, no intervention is needed. The left basilar joint (the patient €™s dominant hand) is symptomatic, and an initial trial of conservative therapy is indicated. One study found that 70% of patients undergoing conservative therapy were able to avoid surgery in the long term. The grind test is performed by holding the thumb metacarpal and applying axial compression while rotating the metacarpal in a circular motion. Pain and crepitance indicate a positive result. Early stages of basal arthritis can be treated with ligament reconstruction. The goal of this operation is reconstruction of the volar beak ligament of the thumb metacarpal and reinforcement of the dorsal ligaments. Metacarpal extension osteotomy is an alternative operation for early basal arthritis. The goal of this operation is to unload the palmar joint surfaces. More advanced stages of basal arthritis require either partial or complete resection of the trapezium. Silicone implant arthroplasty has fallen out of favor because of long-term complications such as implant wear, implant fracture, and subluxation. The most common treatment for advanced pantrapezial arthritis is excision of the trapezium with ligament reconstruction and metacarpal suspension. Hematoma and distraction arthroplasty is excision of the trapezium without tendon interposition. In this technique, Kirschner wires are placed for six weeks to maintain the trapezial space. Bone stimulation does not play a role in the treatment of basilar joint arthritis.

Answer 29

The correct response is Option E. Minimally or nondisplaced fractures of the distal radius may be associated with significant complications, including nonunion, malunion, stiffness, and tendon ruptures. The extensor pollicis longus (EPL) and the extensor digitorum communis tendons are the most frequently ruptured tendons after distal radius fracture. Rupture of the EPL tendon is more common in minimally or nondisplaced fractures of the distal radius. The management of EPL ruptures is surgical exploration and transfer of the extensor indicis proprius tendon to the distal stump of the EPL tendon. This tendon transfer is a simple procedure that retains the extensor function of the index finger. Generally, EPL rupture occurs late. A zone of relative ischemia within the tendon weakens the EPL until rupture occurs. With rupture of the EPL tendon, the proximal muscle and tendon retracts. Direct repair is not possible or would place excessive tension on the repair. Grafting of the gap lays the tendon graft in a scarred bed and motors the muscle €‘tendon unit with a contracted muscle. Fusion of the interphalangeal joint of the thumb would not be optimal treatment because a simple tendon transfer exists; however, it may serve to be a viable option if there are multiple tendon ruptures and no sufficient transfers exist. Splinting will not restore tendon function. Tenolysis is indicated for tendon adhesions but has no role in the management of a tendon rupture. Interphalangeal joint arthrodesis is a more reasonable option with a similarly ruptured flexor pollicis longus where the flexor sheath is scarred.

Answer 30

The correct response is Option D. The patient described has scapholunate advanced collapse (SLAC wrist). Components of a SLAC wrist include radioscaphoid, capitolunate, and scaphocapitate arthritis. The capitate wedges itself between the scaphoid and lunate as it slides off the ulnar articular surface of the scaphoid. Typically, the articulation of the lunate with the distal radius is preserved, although there are advanced degenerative changes elsewhere in the wrist. In the radiograph shown, the radiolunate and the scapho-trapezio €‘trapezoid (STT) joints appear preserved. The STT joint is unlikely to be the source of pain considering the clinical history and the radiographic appearance. Therefore, STT arthrodesis is incorrect. Radioscaphoid arthrodesis is unlikely to relieve all symptoms in this patient because of the presence of multiple other arthritic joints. Injection of dexamethasone into the wrist may provide some relief; however, this is not a long €‘term solution. Total wrist arthrodesis is excellent for control of pain caused by advanced osteoarthritis; however, this pain control comes at the expense of loss of mobility. Because of the preservation of the radiolunate joint, a limited wrist arthrodesis (scaphoidectomy and four €‘corner fusion) is a superior alternative. This is because the arthritic joints can be fused or eliminated while preserving wrist motion. Therefore, total wrist arthrodesis is not the best option.

Answer 31

The correct response is Option E. This patient has sustained a trans-scaphoid, dorsal perilunate, volar lunate fracture dislocation. In addition to pain in the wrist, this injury often presents with acute carpal tunnel syndrome, which must be recognized promptly and treated emergently. The lunate must be relocated from the carpal canal to the carpus, and the associated hematoma must be evacuated. After the lunate has been relocated, the volar radiocarpal ligaments must be repaired. Correct carpal alignment usually requires dorsal and volar approaches using a Kirschner wire in the lunate to function as a joystick. Reduction and fixation of the scaphoid are also required. Acute carpal tunnel syndrome indicates ongoing compression and ischemia of the median nerve. Conservative measures such as elevation of the hand and serial measurement of compartment pressures are contraindicated. Proximal row carpectomy and scapholunate arthrodesis are options for treatment of degenerative arthritis of the wrist but should not be used as primary treatment of a fracture dislocation.

Answer 32

The correct response is Option D. This patient's radiocarpal angles suggest scapholunate instability and secondary dorsal intercalated segment instability. Scapholunate instability is a result of an injury to the scapholunate interosseous ligament and is the most common form of wrist instability. The scapholunate interosseous ligament is the primary stabilizer of scaphoid motion in linked carpal motion. A normal scapholunate angle is approximately 46 degrees with a range of 30 to 60 degrees. Scapholunate angles greater than 60 degrees tend to imply a scapholunate interosseous ligament injury, whereas angles less than 30 degrees tend to imply a lunotriquetral interosseous ligament injury. The radiolunate angle is normally 0 to 11 degrees. The lunate can be thought of as a balanced cup on the lateral radiograph, and its articular surface should point straight vertical. The scaphoid acting through the scapholunate interosseous ligament tends to pull the lunate forward, whereas the lunotriquetral interosseous ligament tends to pull the lunate dorsally. Therefore, an injury to the scapholunate ligament allows the triquetrum to exert an extension force on the lunate, pulling it into a dorsally tipped position, which is referred to as a dorsal intercalated segment instability (DISI) deformity. The scapholunate gap is normally 2 mm; a gap greater than or equal to 3 mm is believed to be abnormal and may or may not be present in cases of scapholunate instability. The dorsal capsule is believed to be one of several secondary stabilizers of the scaphoid and may or may not be injured in this scenario. The ligament of Testut, also know as the radioscapholunate ligament, and the triangular fibrocartilage complex are not believed to contribute to carpal stability.

Answer 33

The correct response is Option D. This patient has sustained an injury to the scapholunate ligament. His injury is not recent, as evidenced by the arthritis that is involving the radiocarpal joint and radial styloid. The radiograph suggests a scapholunate injury because of the widened gap between the scaphoid and lunate bones and the widened scapholunate angle (greater than 60 degrees on lateral view). When patients present early, for example within three months of injury, the scapholunate ligament can be repaired and a dorsal capsulodesis procedure can be performed to strengthen the repair. However, when they present later, especially after developing arthritis, the edges of the scapholunate ligament usually cannot be reapproximated and the pain elicited by the arthritis will not be relieved. A wrist arthrodesis may be an option if the lunate fossa of the radius or capitate head are involved with arthritis. However, in this patient, proximal row carpectomy would be the most appropriate management. Patients who undergo proximal row carpectomy usually recover 70% to 80% grip strength and 50% to 60% range of motion. Most patients who undergo proximal row carpectomy have resolution of pain. The scapholunate ligament can be reconstructed with the flexor carpi radialis tendon, AlloDerm, or bone ligament bone construct, but this is not an alternative in an individual who already has arthritis. The scaphoid has not been fractured; therefore, open reduction and internal fixation is not needed. Postoperative radiographs are shown.

Answer 34

The correct response is Option C. In patients with symptomatic arthritis of the trapezial metacarpal joint of the thumb, initial conservative treatment includes nonsteroidal anti-inflammatory drugs, splinting, and injection of corticosteroids. If conservative treatment fails, surgery is a good option for pain relief. The standard surgical treatment is trapezial excision. Trapezial excision can be performed alone or along with ligament reconstruction and tendon interposition using the flexor carpal radialis tendon or the abductor pollicis longus tendon. Trapezial excision may also be combined with silicone joint replacement. Several studies have been performed comparing all three of these options with the conclusion that there is no significant difference between any of the surgical options in regard to relief of pain or pinch strength. Silicone prostheses have the potential problems of displacement and silicone synovitis.

Answer 35

The correct response is option B. Proximal pole scaphoid fractures are at increased risk for devascularization. This is visible radiographically with an un-united fracture line and, potentially, sclerosis or whitening of the proximal pole fragment. Left untreated, there is a near 100% incidence of degenerative joint disease, i.e., scaphoid nonunion advanced collapse (SNAC wrist). However, in this case, the articulations between the radius and scaphoid, scaphoid and capitate, and capitate and lunate are preserved. Therefore, scapholunate advanced collapse (SLAC wrist) and SNAC wrist are incorrect. SLAC wrist is commonly associated with scapholunate ligament injuries and a dorsal intercalated segmental instability pattern (DISI deformity). In this pattern, the lunate assumes an extended position while the scaphoid flexes. In both SNAC wrist and SLAC wrist, the initial degeneration occurs both in the distal scaphoid and the radial styloid. Scapho-trapezio-trapezoid (STT) arthritis is incorrect because there are no degenerative joint changes in the STT joint on the radiograph. Kienbock=s disease is avascular necrosis of the lunate which is present on the radiograph. Treatment of un-united proximal pole function of the scaphoid is difficult. Options include simple compression, fixation with a bone graft or bone flap, and excision with or without tendon in position arthroplasty.

Answer 36

The correct response is Option C. This patient has a scapholunate advanced collapse (SLAC) pattern of degenerative wrist arthritis. To achieve the goals of pain relief and maintenance (or improvement) of wrist motion, scaphoid excision with arthrodesis of the capitate-lunate-hamate-triquetrum is the treatment of choice. If this patient were not concerned about wrist motion, total wrist arthodesis could be performed. Revascularization of the lunate is more appropriate for the treatment of Kienbock disease, which is believed to result from microfractures of the lunate that lead to ischemic changes and vascular necrosis. Proximal row carpectomy will result in the diseased capitate being inserted into the lunate fossa. Resurfacing of the capitate would be required for this to be a viable option. Neither scaphoid excision alone nor scaphoid-trapezium-trapezoid arthrodesis will treat the diseased capitolunate joint. Radioscapholunate arthrodesis will also fail to treat the diseased capitolunate joint. This would be a reasonable treatment for joint changes confined to the radiocarpal joint, where the midcarpal joint is normal. If this is done, resection of the distal third of the scaphoid may help minimize impingement and loss of motion in radial deviation and flexion.

Answer 37

The correct response is Option E. The radiograph shows radial subluxation of the metacarpal of the thumb on the trapezium, osteophytic spurring, sclerosis, and articular irregularities of the joint surfaces. The carpometacarpal grind test differentiates radial subluxation from other common sources of wrist pain. For this maneuver, the thumb ray is loaded axially and rotated, stressing the carpometacarpal (basal) joint. If the joint is significantly diseased, pain that mimics the pain resulting from normal hand movement will be reproduced. The Finkelstein test is used to identify de Quervain’s tenosynovitis. With this maneuver, the thumb is grasped by the fingers in the palm of the hand, and the wrist is ulnarly deviated. This movement accentuates pain over the first dorsal compartment and indicates the presence of tenosynovitis in this region. The Phalen test is a common maneuver used to diagnose carpal tunnel syndrome. Numbness, tingling, or pain in the distribution of the median nerve is produced with wrist flexion. The scaphoid shift test is performed by palpating the area over the scaphoid tuberosity and moving the wrist from an ulnar to a radial direction. The scapholunate ligament becomes stressed as the scaphoid assumes a more vertically oriented position with radial deviation. Pain with this maneuver indicates a scapholunate ligament injury. The distal radioulnar shuck test is performed by stressing the distal radioulnar joint dorsally and palmarly by moving the radius dorsally and the ulna palmarly, or vice versa. Reproduction of pain by this maneuver indicates possible disease of the triangular fibrocartilage complex or distal radioulnar joint.

Answer 38

The correct response is Option D. The most appropriate management of this condition is release of the pisohamate and volar carpal ligaments. This patient has ulnar tunnel syndrome or compression of the ulnar nerve in Guyon’s canal. Nerve conduction studies and electromyography can be used to confirm the diagnosis. Conservative treatment includes activity modification, splinting, and administration of a nonsteroidal anti-inflammatory drug. Surgical management involves release of the ulnar tunnel, which is 4 to 4.5 cm in length, beginning at the proximal volar carpal ligament and ending at the fibrous edge of the hypothenar muscles. Zone I is the region of the tunnel proximal to the bifurcation of the nerve. Zone II is the area around the deep motor branch, and Zone III is the area surrounding the superficial branch. The ulnar nerve courses between the volar carpal ligament and the transverse carpal ligament. Release of the transverse carpal ligament is appropriate for management of compression of the median nerve at the wrist (carpal tunnel syndrome). Osborne’s ligament and the arcade of Struthers are potential sites of compression of the ulnar nerve at the elbow. The arcade of Struthers is 8 to 10 cm proximal to the medial epicondyle and extends from the medial intermuscular septum to the medial head of the triceps. The fascia of Osborne is a band bridging the two origins of the flexor carpi ulnaris muscle and the medial epicondyle.

Answer 39

The correct response is Option A. In manual laborers, the pounding of the hypothenar area on machinery can cause thrombosis of the ulnar artery resulting in acute hypoperfusion of the hand. In patients who have an incomplete palmar arch, the less dominant radial artery is unable to provide adequate blood flow to the ulnarmost three digits, resulting in ischemic symptoms to the hand. Raynaud’s phenomenon, which is a vasospastic condition occurring mostly in women, causes vasoconstriction of the vessels to the hand. Thoracic outlet syndrome is a neurologic and/or vascular compression syndrome occurring in the neck. Thromboangiitis obliterans, or Buerger’s disease, is a vaso-occlusive disease occurring mainly in smokers. Vascular malformations are congenital, arterial, or venous, which typically do not cause ischemia.

Answer 40

The correct answer is Option E. The primary advantage of wrist disarticulation, when compared with below-elbow amputation, is preservation of the distal radioulnar joint, resulting in improved pronation and supination. The level of amputation does not affect the incidence of cold intolerance, elbow contracture, or phantom pain. Prosthetic fitting may be more challenging with the excess length.

Answer 41

The correct response is Option B. This patient has severe rheumatoid arthritis of the distal radioulnar joint. Disease of this joint gradually inhibits rotation around the axis of the forearm. If the radiohumeral articulation at the elbow is functional, resection of the distal ulna can produce significant improvement in supination and pronation of the forearm and hand. Darrach resection is a simple surgical procedure that is often combined with other reconstructive surgical procedures in the comprehensive treatment of severe rheumatoid arthritis. Therapy is started almost immediately after surgery. This patient had dramatic improvement in supination and pronation of the forearm amounting to 160 degrees after undergoing Darrach resection. She also underwent metacarpophalangeal joint arthroplasty of the index, long, and ring fingers, centralization of the extensor tendons, transposition of the extensor retinaculum, carpal tunnel release with synovectomy, and arthrodesis of the interphalangeal joint of the thumb. Arthrodesis of the scaphotrapeziotrapezoid joint, proximal row carpectomy, repair of the triangular fibrocartilage complex, and scaphoidectomy will not improve this patient=s forearm supination and pronation. Arthrodesis of the scaphotrapeziotrapezoid joint is effective for management of trapezial arthritis. Proximal row carpectomy is most commonly used to alleviate pain and limited motion in patients with scapholunate advanced collapse of the wrist. Repair or debridement of the triangular fibrocartilage complex is often appropriate for patients with pain at the ulnar aspect of the wrist who have documented tears. Scaphoidectomy is often combined with four-corner arthrodesis of the capitate, hamate, triquetrum, and lunate to manage scapholunate advanced collapse of the wrist.

Answer 42

The correct response is Option D. Basilar joint arthritis is one of the most common arthritic conditions of the wrist. The amount of force exerted between the pulp of the index finger and thumb during pinch is magnified more than 12-fold by the time the force is exerted at the carpometacarpal joint. Four degenerative stages of arthritis at the basilar joint have been described. Loss of cartilage between the first metacarpal and the trapezium causes eburnation of the subchondral bone, loss of joint space, and formation of cysts and osteophytes. The volar oblique ligament (beak ligament) attenuates, and the first metacarpal subluxes in a radial direction off the trapezium. Osteophytes often grow within the space between the first and second metacarpal. With subluxation of the metacarpal, the thumb is drawn into more adducted position, and patients often have poor abduction of the thumb, weakened grip, and pain at the carpometacarpal joint. Rupture of the extensor pollicis longus tendon is not associated with this condition.

Answer 43

The correct response is Option E. This patient has scapholunate advanced collapse of the wrist, also known as SLAC wrist, with radioscaphoid arthrosis and a dorsiflexed intercalated segment instability deformity. This condition is caused by incompetency of the scapholunate ligament, which leads to rotatory subluxation of the scaphoid. SLAC is the most common cause of degenerative arthritis of the wrist. This condition can be classified according to four stages, as shown in the table below. Stage I Radioscaphoid Stage II Radial midcarpal Stage III Ulnar midcarpal Stage IV Pancarpal Surgical management is aimed at decreasing pain and optimizing wrist function, using two unaffected articular surfaces if possible. In this patient, goals of surgery include eliminating the radioscaphoid articulation and stabilizing carpal kinematics. Therefore, the most appropriate procedure is scaphoid excision and four-corner arthrodesis between the lunate, capitate, hamate, and triquetrum. None of the other procedures addresses all of the problems that are present in this patient’s wrist.

Answer 44

The correct response is Option E. In this 39-year-old assembly line worker who has significant degenerative arthritis of the trapeziometacarpal joint (ie, carpometacarpal joint of the thumb) of the dominant hand, the most appropriate management is trapeziometacarpal arthrodesis. Arthrodesis is recommended for younger patients who have arthritis that is limited to the trapeziometacarpal joint and who require strong grip and pinch. This procedure may increase stresses across the peritrapezial joints, leading to pain, laxity, and subsequent arthritis. In addition, some range of motion of the thumb is sacrificed, but this may improve over time. Other potential options include partial trapeziectomy and interposition of the palmaris longus, which is a new arthroscopic technique that has demonstrated promising results but is not yet used widely. Trapeziectomy, with or without soft-tissue interposition arthroplasty, is most commonly used to treat trapeziometacarpal arthritis because it provides relief of pain and increased mobility. However, this technique results in a decrease of pinch and grip strength to approximately 75% of normal. Silastic arthroplasty is performed only in low-demand patients who have adequate bone stock. Reconstruction of the palmar oblique (beak) ligament is indicated for treatment of prearthritic, painful instability of the trapeziometacarpal joint, and may prevent the development of arthritis. However, this procedure will not alleviate pain once significant arthritic changes have occurred.

Answer 45

The correct response is Option D. This patient has a scaphoid-perilunate fracture-dislocation, also known as a scaphoid-dorsal perilunate fracture-dislocation. Wrist dislocations can range from simple injuries to extended fractures associated with dislocation of one or more carpal bones. This patient has sustained one of the most severe forms of wrist dislocation, as shown in the radiographs. Fracture-dislocations of the wrist are identified according to the carpal bone(s) involved and the type of lunate dislocation (ie, incomplete or complete). Lunate dislocations are subdivided into midcarpal lunocapitate, complete lunate, and perilunate injuries. A complete lunate injury can be differentiated from a perilunate injury by the presence of a concomitant dislocation of the radiolunate joint. Greater arc injuries are typically caused by high-energy trauma. The radial styloid, scaphoid, capitate, hamate, triquetrum, and/or ulnar styloid may be fractured. Lesser arc dislocations involve injury to the scapholunate, lunocapitate, and/or lunotriquetral intervals; these injuries are rated as type I to type IV according to Mayfield’s classification. The radiographs do not depict a carpometacarpal joint-hamate fracture-dislocation. A fracture-dislocation of the radial styloid would occur more proximally. The scaphocapitate and scaphotrapeziotrapezoid lie distal to the level of injury.

Answer 46

The correct response is Option A. Fractures of the scaphoid comprise as many as 60% of all carpal bone fractures; most of these fractures are caused by a fall onto a dorsally flexed wrist. Scaphoid fractures can be displaced or nondisplaced. In patients with nondisplaced fractures, application of a cast followed by mobilization results in a rate of union as high as 95%. A long arm thumb spica cast is typically applied first, then replaced with a short arm thumb spica cast. In contrast, displaced fractures are often associated with an unacceptably high rate of nonunion if treated conservatively and a high incidence of avascular necrosis. This complication has been reported to occur in 13% to 40% of patients with scaphoid fractures; its incidence is dependent on the presence or absence of displacement and the anatomic location of the fracture. Because perforators to the scaphoid enter distally and proceed proximally, fractures that occur more proximally are more likely to interrupt the blood supply to the scaphoid. The distal pole of the scaphoid has a good, protective blood supply; as a result, the risk for avascular necrosis is low. In contrast, fractures of the scaphoid waist are associated with an incidence of avascular necrosis of approximately 30%, and fractures of the proximal pole of the scaphoid have a rate of avascular necrosis that may be as high as 100%. Therefore, internal fixation is generally advocated for treatment of fractures of the proximal pole of the scaphoid. With rigid fixation of the bone, revascularization of the scaphoid occurs almost uniformly.

Answer 47

The correct response is Option D. Approximately two-thirds of carpal fractures involve the scaphoid, and more than 90% of nondisplaced scaphoid fractures treated by cast immobilization result in bony union. However, fracture displacement disrupts the retrograde endosteal blood supply of the scaphoid. In patients with scaphoid fractures that are displaced more than 1 mm treated with cast immobilization, approximately 55% have nonunion, and 50% ultimately develop avascular necrosis. Fractures of the proximal pole of the scaphoid are associated with an incidence of avascular necrosis approaching 100%. Appropriate management of a displaced fracture of the scaphoid bone involves reduction and compressive, rigid fixation. Pedicled bone flaps can be used to revascularize the nonhealing scaphoid bone. These flaps are based on septal perforators from the adjacent extensor compartments. A bone flap based on the septum between the first and second extensor compartments is used most commonly. Bone flaps from the distal radius have been shown to improve the rate of bone healing in patients who have nonunion of the scaphoid. According to one study of ten patients who underwent reconstruction with a pedicled bone flap for long-term nonunion of fractures of the proximal pole of the scaphoid, approximately 100% demonstrated union, at an average of twelve weeks after surgery. In addition, in those patients who have Kienbšck disease (avascular necrosis of the lunate), successful revascularization of the lunate has been shown to occur. Although bone grafts from the distal radius have been used in the past, they do not provide vascularized bone for grafting at the avascular site of the fracture.

Answer 48

The correct response is Option C. In this patient who has an acute scapholunate ligament tear, the most appropriate management is operative repair through a dorsal incision. Surgery should be expedited in patients who have acute scapholunate ligament tears associated with carpal instability because degenerative wrist arthritis is likely to occur if the diastasis and carpal collapse are not corrected. The tear is repaired through a dorsal approach, and the carpal collapse is reduced with Kirschner wires. Pin fixation of the reduced scapholunate joint is performed under fluoroscopic control. The scapholunate ligament is repaired either directly or with suture anchors if necessary. Dorsal (ie, Blatt) capsulodesis will augment the repair and further stabilize the rotary subluxation of the scaphoid. According to Mayfield's classification of progressive perilunate instability patterns, the stage of injury correlates directly with the progression of ligamentous injury around the lunate. Stage I involves instability of the scapholunate joint, or tearing of the scapholunate and volar radioscaphoid ligaments. Stage II is dislocation of the capitate. Separation of the lunate and triquetrum is seen in stage III. Lunate dislocation is classified as stage IV. Greater and lesser arc injuries are also associated with perilunate dislocations. Greater arc injuries can include fractures of the radial styloid, scaphoid, capitate, triquetrum, and ulnar styloid. Lesser arc injuries are classified according to the stages of Mayfield's progressive perilunate instability. Application of a long arm cast without operative repair does not address the injury and is likely to result in degenerative wrist arthritis. Percutaneous pin fixation is appropriate only in patients who have diastasis of the scapholunate joint that can be corrected with this technique. Pin fixation is difficult in a patient who has a carpal collapse pattern and would most likely be ineffective. Proximal row carpectomy and scapholunate arthrodesis are contraindicated in patients with acute injuries and are instead reserved for management of certain types of late degenerative wrist arthritis.

Answer 49

The correct response is Option C. In this patient who has a displaced fracture of the scaphoid waist, the most appropriate management is open reduction and compression screw fixation. This can be accomplished using a Herbert, Herbert-Whipple, or Accutrak screw; the Herbert-Whipple and Accutrak screws are cannulated to allow for guided pin placement. Compression screw fixation allows reduction of the fracture and compression across the fracture site, decreasing the risk for nonunion and the time required for immobilization. Although some surgeons suggest that adequate screw fixation allows early protected range of motion and eliminates the need for cast application, most physicians still recommend postoperative cast immobilization for three to six weeks. This shortened period of immobilization decreases the potential for muscle atrophy and joint stiffness and allows the patient to return to work sooner. Previously recommended techniques for management of displaced fractures of the scaphoid waist, including prolonged immobilization in a long arm cast for three months or longer, have been associated with nonunion or malunion rates ranging from 30% to 40%. Kirschner wire fixation is considered an acceptable fixation method, but is associated with higher rates of nonunion than compression screw fixation. In addition, Kirschner wires are typically buried for an extended fixation time to allow bony union and require an additional operative procedure for removal. Scaphoidectomy is appropriate for management of patients with malunion or nonunion who develop scaphoid nonunion advanced collapse (SNAC wrist), which is a progressive, patterned arthritis of the wrist that may develop in a patient with nonunion. This procedure can be performed adjuvantly with proximal row carpectomy or four-corner arthrodesis, depending on the pattern of arthritis seen in the patient. It is not appropriate in patients with acute injuries.

Answer 50

The correct response is Option D. In this patient who has a nondisplaced transverse fracture of the scaphoid waist, the wrist should be immobilized in a thumb spica cast for 10 to 14 weeks. Most surgeons agree that acute nondisplaced scaphoid fractures will generally heal if the wrist is immobilized adequately for two to three months. Some surgeons recommend immobilization in a long arm cast for the first several weeks and replacement with a short arm cast for the duration of the healing period. Open reduction and internal fixation are indicated in patients who have scaphoid fractures with displacement of more than 1 mm because the blood supply to the bone is likely to be disrupted. Because this blood supply enters the scaphoid distally and proceeds proximally, fractures of the tubercle and distal third of the scaphoid exhibit a more rapid healing process. Therefore, casting for no more than four to six weeks is recommended in patients with fractures of the distal third of the scaphoid if there is no displacement. In contrast, the proximal pole of the scaphoid receives the poorest blood supply, and nondisplaced fractures of the proximal pole of the scaphoid would typically be immobilized for four to six months to allow for bony union. Instead, open reduction and internal fixation can be performed even if the fracture is nondisplaced. Electrical stimulation or ultrasound can be used adjunctively to treat delayed bony union. Because fracture healing is variable, frequent follow-up examination and radiographs are indicated. CT scans show fracture callus and bridging trabeculae in healing scaphoid fractures.

Answer 51

The correct response is Option B. This patient has pantrapezial osteoarthritis of the basal joint of the thumb, as shown in the radiograph. Degenerative arthritis of the basal joint of the thumb can affect the carpometacarpal, scaphotrapeziotrapezoid, and radiocarpal joints. This condition is common in laborers or other persons with occupations that require extensive hand functions. Pantrapezial arthritis manifests as pain at the base of the thumb that is exacerbated with pinch, grasp, lifting, or twisting functions. Failure of the volar beak ligament is the most common initial finding. Patients typically have trouble opening jars and buttoning their clothes. Tenderness that is increased with direct compression and axial loading on physical examination will isolate the osteoarticular level of the thumb. Progressive dorsal subluxation of the basilar joint of the thumb may result in hyperextension of the metacarpophalangeal joint. Posteroanterior, oblique, lateral, and Robert's view radiographs of the thumb should be obtained. The treatment of pantrapezial osteoarthritis depends on the stage of the disease. In patients in the early stages of arthritis, joint protection, modification of activity, and administration of nonsteroidal anti-inflammatory drugs are recommended. A splint can be based at either the hand or forearm. Injection of a corticosteroid may be considered in those patients who have significant pain. If conservative management is unsuccessful, surgery is an option. The goals of surgery include stability and functional positioning of the thumb. In this patient, trapeziectomy, reconstruction of the volar beak ligament, and tendon interposition arthroplasty are indicated. Dorsal opening wedge osteotomy of the thumb metacarpal is more appropriate for patients in the earlier stages of arthritis. Although silicone and metal implants have been used in the past, the trapezium would only be partially resected to fit the implant; therefore, this patient's pain would not be relieved completely. Arthrodesis of the carpometacarpal joint is indicated in patients who have high work demand, and is associated with nonunion. Patients who undergo this procedure are unable to flatten the palm. Scaphotrapeziotrapezoid arthrodesis would not treat the involved joint.

Answer 52

The correct response is Option E. Patients with basilar joint arthritis of the thumb typically have involvement of the trapeziometacarpal joint; the scaphotrapeziotrapezoidal joint is involved less frequently. Conservative management including splinting, administration of anti-inflammatory agents, and joint protection should be attempted first. Recent studies have shown that administration of glucosamine and chondroitin sulfate may aid in alleviation of pain. Both arthroplasty and arthrodesis are recommended in patients in whom conservative management has been unsuccessful. Either procedure will alleviate pain in the diseased trapeziometacarpal joint. Because arthroplasty has limited use in manual laborers who require durability, arthrodesis is more appropriate. Although trapeziometacarpal arthrodesis permits pain-free powerful grip and pinch, this procedure places greater motion demands on the metacarpophalangeal and scaphotrapezial joints. Another disadvantage of trapeziometacarpal arthrodesis is that the procedure results in a decrease in thumb metacarpal motion; as a result, hand span will be decreased, and the patient will be unable to flatten the palm completely. The other procedures do not address the trapeziometacarpal joint of the thumb and thus are not indicated.

Answer 53

The correct response is Option D. This patient has findings consistent with scapholunate dissociation and longitudinal carpal instability. Scapholunate dissociation involves mechanical disruption of the ligament between the scaphoid and lunate bones. Anteroposterior radiographs will show an increased scapholunate gap; the scaphoid bone will appear foreshortened. Comparison radiographs with the opposite, unaffected wrist and anteroposterior radiographs with the fist clenched are also helpful in diagnosis. Early recognition and treatment are important to prevent the development of radiocarpal arthritis following injury, which can ultimately progress to scapholunate advanced collapse (SLAC wrist). Interestingly, this patient's radiograph also shows diastasis of the capitatohamate joint and the third and fourth metacarpals. This is a rare finding that is only seen following high-energy injuries and should be treated as soon as possible. Kienbšck's disease, or avascular necrosis of the lunate, is a progressive condition associated with an ulnar negative variance. Radiographs will show sclerosis or fragmentation of the lunate or loss of lunate height, depending on the stage of the disorder. In patients with midcarpal instability, the proximal row is shifted into either dorsiflexed or volar-flexed intercalated segment instability. There is destabilization between the distal and proximal carpal rows on radial or ulnar deviation of the wrist. However, separation of the scaphoid and lunate bones would not be evident on radiographs. Perilunate dislocations can be classified as either greater arc or lesser arc injuries depending the site of trauma and the extent of carpal bone injury. Anteroposterior radiographs will show overlap of the distal carpal row onto the proximal carpal row and a triangular-shaped lunate. Scapholunate syndrome develops following fracture of both the scaphoid and capitate. The proximal pole of the capitate will typically be rotated either 90 degrees or 180 degrees.

Answer 54

This patient has findings consistent with scapholunate advanced collapse (SLAC wrist), a common pattern of degenerative arthritis of the wrist. This patient's condition developed following an undiagnosed scapholunate injury; other common causes include rotary subluxation or nonunion of the scaphoid, Preiser's disease, and Kienbšck's disease. The radiograph shows a 2.5-mm diastasis of the scapholunate joint, as well as proximal migration of the capitate between the scaphoid and lunate and loss of capitolunate joint space. The capitate will ultimately become wedged between the scaphoid and lunate. Pantrapezial arthritis is an advanced type of basal joint arthritis of the thumb that involves the carpometacarpal and scaphotrapeziotrapezoid joints. A grind test will be positive. In radiocarpal arthritis, loss of joint space between the scaphoid and its fossa will be visible on radiographs, and the patient will have pain in the region of the anatomic snuff box. In contrast, patients with scaphotrapeziotrapezoidal (STT) arthritis will have loss of the STT joint space and positive findings on grind testing. Ulnar-sided wrist pain is typically the initial symptom of a tear of the triangular fibrocartilage complex; arthrography or arthroscopy should be used to confirm the diagnosis.

Answer 55

The correct response is Option C. The patient has scapholunate advanced collapse (SLAC) wrist with both radiocarpal and intercarpal arthritis, involving the radioscaphoid and capitolunate articulations. In this procedure, scaphoidectomy eliminates the arthritic radioscaphoid articulation, and fusion of the capitate, hamate, lunate, and triquetrum bones will address the intercarpal capitolunate arthritis. This limited wrist fusion will still allow some degree of movement at the wrist. Arthrodesis of the radiolunate joint is used to prevent ulnar translation of the carpus in cases of radiocarpal arthritis, such as in rheumatoid arthritis. This would not address the issue of radioscaphoid or capitolunate arthritis. Proximal row carpectomy is a treatment option for SLAC wrist and an alternate option to scaphoidectomy and four-corner fusion in many cases. However, this would not be the best choice in the presence of capitolunate (midcarpal) arthritis, since the remaining postoperative articulation of the capitate bone to the radius would involve retaining an arthritic joint surface. Osteochondral resurfacing of the arthritic capitate head has been proposed but is still somewhat controversial. Silicone wrist arthroplasty can preserve some motion and decrease pain in the setting of wrist arthritis, but it is typically used in cases of low physical demand (such as rheumatoid arthritis) and would not be the best choice in a manual laborer. Excessive force can result in implant failure. Total wrist arthrodesis would relieve wrist pain from arthritis at the expense of losing motion. This is a good strategy for pancarpal arthritis and may be used for pain relief in the high-demand wrist, but it will not preserve motion. Ligament reconstruction is contraindicated in the presence of arthritis or SLAC wrist.

Answer 56

The correct response is Option E. Trauma caused by a longitudinal force onto an outstretched hand with the elbow in extension, resulting in distal radioulnar joint instability, raises the concern for an Essex-Lopresti injury or Galeazzi injury. In the Essex-Lopresti injury, energy is transmitted in a longitudinal direction proximally, causing distal radioulnar joint instability, tears of the interosseous membrane, and a radial head fracture. In the Galeazzi injury, the radial shaft is fractured, creating instability of the distal radioulnar joint. Wrist x-ray studies often demonstrate ulnar positivity because of proximal migration of the radius. Distal radioulnar joint widening or distal radioulnar impingement can also be seen. Forearm and elbow x-ray studies are the appropriate study to order next, to assess for a more proximal fracture. A clenched-fist x-ray study is often performed bilaterally and is useful to assess for scapholunate interval widening. An MR arthrogram of the wrist, in this situation, would likely demonstrate leakage of dye from the ulnocarpal joint space into the distal radioulnar joint, indicating a triangular fibrocartilage complex injury. However, this would not be necessary before elbow x-ray studies. Furthermore, MR arthrography is an invasive procedure that is not appropriately done in an emergency room setting. A wrist CT scan could demonstrate occult wrist fractures not identified on plain x-ray studies. A 30-degree supinated lateral x-ray study is useful in addressing fourth and fifth metacarpal fractures, which can sometimes be difficult to see on standard hand/wrist x-ray study views.

Answer 57

The correct response is Option B. Following scapholunate interosseous ligament injury, a predictable pattern of dorsal intercalated segment instability evolves. Evolution of changes occurs first in a dynamic pattern (seen only with loading, such as fluoroscopy or clenched-fist x-ray study views), followed by a static instability pattern (seen on plain x-ray study), followed by degenerative changes, or scapholunate advanced collapse (SLAC). Lunate extension is seen as part of dorsal intercalated segment instability, together with flexion of the scaphoid and widening of the scapholunate gap greater than 3 mm. The scapholunate angle increases greater than 60 degrees. Lunate flexion is not seen in isolated scapholunate injuries, and together with extended posture of the capitate is seen in volar intercalated segment instability (VISI) due to lunotriquetral ligament injuries or secondarily as part of carpal instability adaptive. Scaphoid cyst formation is not a typical finding in scapholunate injuries. Scaphoid ulnar translocation is not seen as part of scapholunate interosseous ligament injuries; for this to occur there must be a disruption of the radiocarpal ligaments.

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Wrist 01-22, 24 Flashcards

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