Hand - Wrist ligament injuries and fractures Flashcards

Question

A 25-year-old man is brought to the emergency department after falling down a staircase and landing on his outstretched hand. X-ray studies show a perilunate dislocation. The scapholunate and which of the following ligaments must be ruptured for this dislocation to occur? A ) Dorsal intercarpal B ) Dorsal radiotriquetral C ) Lunotriquetral D ) Radioscaphocapitate E ) Ulnotriquetral

Answer 1

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 2

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 3

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 4

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 5

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 6

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 7

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 8

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 9

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 10

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 11

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 12

The correct response is Option C. The mass in question is most likely a dorsal ganglion cyst of the wrist. Sixty to 70% of ganglion cysts are found in the dorsal aspect of the wrist. Dorsal wrist ganglion cysts usually communicate with the joint by a stalk. This stalk usually originates at the scapholunate interval, but it can also rarely arise from other aspects of the dorsal wrist joint. Thirteen to 20% of ganglia are found on the volar aspect of the wrist, and they usually arise from the radioscaphoid, scapholunate, scaphotrapezial, or metacarpotrapezial joint, in decreasing order of frequency. Ganglia arising from the flexor tendon sheath of the hand account for approximately 10%.

Answer 13

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 14

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 15

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 16

Correct answer 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 17

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 18

Correct answer is option C. 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 19

The correct response is Option C. The most appropriate imaging modality is MRI. This patient has presented with a delayed proximal pole scaphoid fracture/nonunion, which was previously untreated. The primary blood supply to the scaphoid enters distally and travels proximally. As a result, perfusion to the proximal portion of the scaphoid occurs in a retrograde fashion. Fractures of the proximal pole of the scaphoid are located at the furthest distance from the blood supply, and these fragments are at risk for nonunion and avascular necrosis. MRI (particularly with gadolinium enhancement) would be the best imaging study for evaluating the blood supply to the scaphoid fragment and looking for the presence of avascular necrosis. MRI can also provide anatomical information regarding the fracture. Direct intraoperative visualization of bleeding of the fragment has also been advocated in assessing vascularity. Angiography can show blood flow patterns, but would not provide anatomic information. CT scan is useful for detailed anatomic analysis of fractures and assessment of healing, but would be less helpful than MRI in determining avascular necrosis. Bone scan shows the presence of inflammatory activity and can be used in identifying the presence of occult fractures (high sensitivity, albeit with low specificity), but has low resolution and would not be helpful in determining avascular necrosis. Ultrasonography has been used in the diagnosis of acute fractures, but would not determine vascularity.

Answer 20

Correct answer 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 21

Correct answer 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 22

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 23

The correct response is Option E. This patient has type IV perilunate dislocation, or lunate dislocation. This represents a complete disruption of the ligamentous stabilizers about the lunate except for the maintained short radiolunate ligament that the lunate rotates on. These injuries are high energy and can be ligamentous only (lesser arc injuries) or include fractures (greater arc injuries), and they are then termed perilunate fracture dislocations. The mechanism of injury involves wrist extension, ulnar deviation, and intercarpal supination. Mayfield described the stages of injury progressing from radial to ulnar in type IV dislocation, including disruption of the scapholunate ligament and radioscaphocapitate ligament, disruption of the lunocapitate joint, disruption of the lunotriquetral ligament, dislocation of the lunate from its fossa at the radiocarpal joint volarly into the carpal tunnel, and disruption of the dorsal radiocarpal ligament. The volar location of the lunate implies a rupture of any dorsal attachments. On the posteroanterior view of the x-ray study of the wrist, there will be disruption of Gilula lines. On a lateral x-ray study, a "spilled teacup" sign is seen

Answer 24

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 25

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 26

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 27

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 28

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 29

Correct answer 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 30

Correct answer 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 31

The correct response is Option B. This patient has a type IV perilunate dislocation, or a true lunate dislocation. This represents a complete disruption of the ligamentous stabilizers about the lunate. These injuries are high energy and can be ligamentous only (lesser arc injuries) or include fractures (greater arc) and are then termed perilunate fracture dislocations. Mayfield et al described the stages of injury progressing from radial to ulnar in a type IV dislocation, including injury of the scapholunate ligament, disruption of the lunocapitate joint, injury of the lunotriquetral ligament, and dislocation of the lunate from its fossa at the radiocarpal joint volarly into the carpal tunnel. On posteroanterior x-ray study of the wrist, there will be disruption of Gilula’s lines. On lateral x-ray study, a “spilled teacup” sign is seen. Closed reduction with relaxation and traction is important, as the lunate needs to be relocated to its fossa to restore relative alignment of the wrist and to decompress the median nerve in the carpal tunnel. Surgical intervention can then be performed for open reduction of the joints and ligament repair after swelling has improved. However, progression in median nerve symptoms in the setting of successful or failed closed reduction is indicative of acute carpal tunnel syndrome and necessitates urgent surgical intervention. Advanced imaging such as MRI is not required but may be helpful. Repeat closed reduction is likely to fail at this time, may worsen the swelling, and is unlikely to resolve the carpal tunnel symptoms. Open reduction of the scaphoid is not emergent, and the patient does not have a scaphoid fracture. Aspiration of the wrist will not resolve the inciting etiology of the patient's carpal tunnel symptoms.

Answer 32

Correct answer 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 33

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 34

The correct response is Option A. This patient presents with severe osteoarthritis of the carpometacarpal (CMC) joint of the thumb. The thumb metacarpal is in adduction, and the proximal phalanx is in hyperextension. The complex range of motion of the thumb basal joint is achieved through stability from 16 ligaments. Of the choices given, only the anterior oblique ligament is in the thumb at the basal joint. It has been found to be the most important preventative measure against radial subluxation in cases of CMC arthritis in biomechanical studies. It originates on the volar tubercle of the trapezium and inserts on the thumb metacarpal volarly. In cases of severe thumb CMC arthritis, the progressive ligamentous incompetence of the anterior oblique ligament and dorsal radial ligament allow the thumb metacarpal to migrate dorsally and proximally. The dorsal radial ligament is also important for basal joint stabilization, while the other ligaments of the thumb basal joint are not as important. The ulnar collateral ligament is located at the metacarpophalangeal (MCP) joint of the thumb, and rupture leads to instability of that joint as seen with gamekeeper’s thumb. The dorsal central ligament is not involved in CMC joint subluxation. The deep transverse metacarpal ligaments are located in the hand between the metacarpal heads and assist in supporting the metacarpal arch. The posterior cruciate ligament helps stabilize the knee by preventing the tibia from slipping posteriorly when flexed.

Answer 35

The correct response is Option B. This patient presents with a scaphoid nonunion advanced collapse arthritis pattern (SNAC). The arthritic pattern follows a pattern very similar to scapholunate advanced collapse (SLAC). Watson and Ballet (JHS, 1984) recognized that chronic scapholunate ligament incompetence led to a predictable sequence of arthritic wear at the radioscaphoid junction (scapholunate advanced collapse [SLAC] stages I and II), later progressing to involve the midcarpal joint (SLAC stage III), usually sparing the spherical radiolunate articulation. Four-corner arthrodesis (capitate-lunate-triquetrum-hamate) with scaphoid silicone prosthetic replacement (silicone replacement later omitted) was Watson and Ballet’s recommended surgical treatment and preferred over proximal row carpectomy. The SLAC pattern of arthrosis is thought to be due to traumatic injury to the scapholunate ligament. Calcium pyrophosphate dehydrate crystal deposition disease (CPPD, or pseudogout) has been reported to be a frequent cause of SLAC-type x-ray changes as well. Scaphoid fracture nonunion can lead to a similar degenerative arthritic pattern of the wrist, called scaphoid nonunion advanced collapse (SNAC). Symptomatic treatment with splints, modalities, and injection may suffice in many patients. There are no studies on the long-term success of nonsurgical treatment for SLAC or SNAC wrist, nor are there any long-term natural history studies. Surgical treatment options for either SLAC or SNAC wrist include partial or complete wrist arthrodesis, proximal row carpectomy (PRC), denervation, or radial styloidectomy. SNAC wrist has the additional potential treatment option of excision of the distal ununited scaphoid fragment. Most studies concerning treatment of SLAC/SNAC wrist have focused on the results of four-corner arthrodesis with scaphoid excision or PRC. Controversy exists concerning whether PRC, or a modification thereof, may be performed when the capitate has arthritic changes. Scaphocapitate arthrodesis, with resection of the lunate, is a treatment option for late-stage Keinböck disease. Scaphocapitate arthrodesis leaves the radioscaphoid joint in place, making it inappropriate for the patient in this case who has radioscaphoid arthritis. Open reduction and internal fixation of the scaphoid is not indicated here, since the arthritic change noted on x-ray study is the sequela of an old scaphoid fracture nonunion, which has now gone on to advanced collapse arthritis. There does not appear to be too much arthrosis in the scaphotrapeziotrapezoid (STT) joint, with the more likely source of the patient's pain related to the radiocarpal joint, so an STT fusion would not be indicated here. This arthrosis is the result of a chronic scaphoid nonunion with subsequent carpal collapse, so repair of the SL ligament would not be indicated.

Answer 36

Correct answer 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 37

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 38

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 39

The correct response is Option B. Peri-lunate dislocations (PLD) and peri-lunate fracture dislocations (PLFD) are considered complex, high-energy injuries with potentially difficult recovery for many patients. In terms of outcomes research, long-term data are considered to be follow-up greater than 10 years. The long-term data are retrospective but consistent across many studies. The treatment of choice for PLD and PLFD is open reduction and internal fixation. Studies looking at closed reduction and casting or percutaneous pin fixation have shown inferior outcomes, and open treatment is recommend by most authors. All studies agree that there will be the presence of moderate or even severe post-traumatic arthritic changes on x-ray in most patients (50 to 100%), which can be various degrees of SLAC, SNAC, or avascular necrosis. However, the data also show that the presence of radiographic arthritis does not necessarily correlate with functional outcomes. On average, patients will achieve 65 to 70% of wrist flexion-extension arc and 80% grip strength compared with the unaffected side. Although some patients may develop severe complications of a PLD or PLFD such as advanced SLAC or SNAC or ulnar translation of the carpus, it is a rare finding. Most studies show outcomes in the good and fair range according to the Mayo wrist score and other outcome measures. Patients with the most severe arthritis usually do correspond to the worst symptoms and may require salvage procedures such as proximal row carpectomy or limited wrist fusion. Persistent, chronic pain is a rare finding with long-term outcomes of perilunate injuries. Pain with heavy activity only is the most commonly reported outcome, although many patients are largely pain free. Patients can have near normal looking x-rays after PLD or PLFD; however, this is rare. One would not expect \>80% of wrist motion after an injury of this magnitude even with normal x-rays. Also, patients with minimal arthritic changes tend to show better functional outcomes.

Answer 40

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 41

The correct response is Option B. Nondisplaced scaphoid fractures may not be apparent on plain radiographs and are better visualized on CT scan. Although the treatment options for nondisplaced scaphoid wrist fractures may include immobilization alone or surgical fixation, nondisplaced distal pole and tubercle fractures are felt to be more stable and can be treated with immobilization alone for 6 to 12 weeks. In addition, these fractures often have small fragments that are not as amenable to compression screw fixation. Observation and physical therapy allow mobilization of the wrist and are not recommended because of the potential for delayed healing or nonunion. Compression screw fixation is not generally necessary and is sometimes not possible for tubercle fractures, but it is a common treatment for scaphoid wrist fractures. Autologous bone grafting and internal fixation is generally reserved for scaphoid nonunions.

Answer 42

Correct answer 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. Kienbock'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 on 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 43

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 44

The correct response is Option B. Scapholunate injuries frequently occur following falls onto an outstretched hand or other wrist trauma. Patients may develop pain and edema about the wrist, and physical examination should include a scaphoid shift test. In the setting of a scapholunate injury, lateral views of plain x-ray studies often demonstrate a scapholunate angle greater than 60 degrees (normal range, 30 to 60 degrees), and clenched fist views frequently demonstrate a scapholunate diastasis greater than 2 cm. A scapholunate interval of 1.5 cm is normal, and the scaphocapitate interval is not used for determination of a scapholunate ligament injury. Additional imaging modalities include MRI and diagnostic arthroscopy.

Answer 45

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 46

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 47

The correct response is Option E. Multidrug resistant bacterial infections continue to rise and antimicrobial overuse is the leading cause for antibiotic resistance. There is growing evidence that prophylactic antibiotic use is not necessary for clean plastic surgery cases, aside from breast surgery cases. Despite consensus guidelines, the use of prophylactic antibiotics for elective Hand Surgery cases continues to increase. Level I evidence exists that demonstrates prophylactic antibiotics are not necessary for clean Hand Surgery cases lasting less than 2 hours. Although there has been concern regarding diabetes and surgical infection risk, this has not been demonstrated in larger studies with multivariate analyses.

Answer 48

The correct response is Option D. The correct answer is plain x-rays. Negative x-rays in scaphoid fractures are up to 30%. Cost effectiveness of obtaining x-rays first is shown by the positive finding in 70%. The predictive value of clinical examination is 13-69% with an average of 21%. Depending on clinical suspicion and whether the patient needs to avoid immobilization if the absence of fracture can be confirmed, additional imaging studies may be obtained. For MRI, the estimated sensitivity is 97.7% and the specificity is 99.8% with 96% accuracy. For a CT scan, estimated sensitivity is 85.2 to 94% and the specificity is 96 to 99.5% with 98% accuracy. Bone scintigraphy is 96 to 97.8% and 89 to 93.5%, respectively, with 93% accuracy. For follow-up x-ray studies, 91.1 and 99.8%, respectively. MRI is therefore the best test for ruling in scaphoid fractures where the other tests are better at ruling out scaphoid fractures. Cost effectiveness of MRI for patients with suspicion for scaphoid fracture with negative x-rays is shown by getting patients out of unnecessary splints sooner.

Answer 49

The correct response is Option B. Osteoid osteoma is a benign bone tumor that arises from osteoblasts; the principal symptom is focal pain at the site of the lesion. Multiple studies suggest that CT is the best imaging technique for detection of this tumor. Specifically, CT is best at depicting the nidus, the radiolucent area typical of this tumor type. Within the radiolucent nidus, a central area of high attenuation is often seen, representing mineralized osteoid. As ultrasound waves do not adequately penetrate bone, this intracortical lesion would not easily be detected by this technique. Although magnetic resonance (MR) has been used to detect these lesions, it is not as sensitive at detecting the nidus as CT scanning. This is because the nidus, especially if it is small, will have signal similar to cortical bone on MR. Although an arthrogram may detect an intra-articular osteoid osteoma, this is a more unusual entity. A bone scan may show the lesion, but it is nonspecific and will not confirm the diagnosis. Laser fluorescence angiography has gained popularity for assessing the perfusion of soft tissues (skin, flaps, etc.), but this technique will not help assess bone or tissues of significant depth, nor can it reliably distinguish tumor from other tissue.

Answer 50

The correct answer 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 51

The correct response is Option B. The CMCJ is very important for hand function and plays a key role in pinch and grasp. The increased range of motion inherent to the thumb CMCJ is attributed to the anatomy of the joint. The biconcave saddle shaped articular surface of the CMCJ also provides some inherent stability. Motion allowed by the joint includes flexion, extension, adduction, abduction, circumduction. Stabilizing ligaments and joint capsule further reinforce the joint, thus thumb CMCJ dislocations are rare injuries. These injuries account for less than 1% of hand injuries. There are five major stabilizing ligaments to the CMCJ: anterior (volar) oblique, ulnar collateral, intermetacarpal, dorsoradial, and dorsal (posterior) oblique. These ligaments are critical stabilizers during motion. The volar oblique ligament and dorsoradial ligaments are considered to be the most important resistive forces in dislocation in cadaver studies. Reports of traumatic thumb CMCJ dislocation have been in a dorsal vector. The volar oblique ligament was originally thought to be the critical resistive ligament; however, recent literature has supported the dorsal complex (includes the dorsoradial and posterior oblique ligaments) are the most critical for restraint of the joint, thus are injured in dorsal dislocations. Timely recognition is important for these injuries as immediate reduction and casting or splinting for 4 to 6 weeks may be adequate to prevent recurrence. However, these injuries are often missed on radiologic examination or may be persistently unstable. Closed reduction and Kirschner wire fixation may be adequate for treatment in persistently unstable injuries. Some authors advocate for open reduction and ligament reconstruction. Delayed treatment especially beyond three weeks will likely require open reduction and ligament reconstruction. These injuries are often missed on x-ray examination as they can be subtle especially in the setting of more obvious trauma. Inadequate treatment puts these patients at increased risk for subsequent posttraumatic osteoarthritis given the joint malalignment. The radiocarpal and dorsal intercarpal ligaments are wrist stabilizer not thumb CMCJ stabilizers.

Answer 52

The correct response is Option B. The correct answer is wrist arthroscopy. Arthroscopy is considered the gold standard for the diagnosis of scapholunate and other intercarpal ligament injuries as the injury is directly visualized. The scapholunate ligament is generally best visualized through the 3,4 portal, and midcarpal joint arthroscopy is also recommended to make the diagnosis. Arthroscopy is the standard that all other modalities are compared against. Standard x-ray studies should be performed for any patient with suspected wrist pathology. In addition to posteroanterior, lateral, and oblique films, both scaphoid and clenched fist views should be obtained. Dynamic scapholunate instability will have normal x-ray studies, and it can take 3 months or longer to see any evidence of scapholunate instability, such as scapholunate diastasis greater than 3 mm or an increased scapholunate angle greater than 70 degrees. Noncontrast MRI is a common method of evaluation for intercarpal ligament tears. The accuracy of MRI is improved with a 1.5-T or greater magnet, thin slices, use of a wrist coil, and reading by a fellowship-trained musculoskeletal radiologist. Studies show that MRI is only about 70% sensitive but highly specific (close to 100%) for scapholunate ligament tears. Arthrography, both conventional CT and MR, can improve the accuracy of imaging. Contrast extravasation to the midcarpal joint is diagnostic of a complete tear but does not examine the extent of the lesion. Arthrography sensitivity and specificity is approximately 95% and 85%, respectively.

Answer 53

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 54

Correct answer 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 55

The correct response is Option B. The posteroanterior x-ray study of the right wrist demonstrates static scapholunate (SL) dissociation with more than 3 mm of widening between the scaphoid and lunate bones. In a normal wrist, with radial to ulnar deviation of the wrist, the proximal carpal bones go into flexion then extension. With ulnar deviation, the hamate bone pushes the triquetrum into relative extension, while the scaphotrapezium-trapezoid (STT) ligament pulls the scaphoid into extension. The lunate follows the direction of its counterparts. With radial deviation, loading across the STT joint pulls the scaphoid into flexion; the lunate and triquetrum follow while translating dorsally and pronating. When there is complete dissociation between the scaphoid and lunate, the dorsal SL ligament and secondary stabilizers (such as the dorsal intercarpal ligament) have failed. Dorsal intercalated segment instability (DISI) describes the abnormal position of the lunate relative to the long axis of the radius. Secondary to the loss of the SL and associated stabilizers, the scaphoid falls into a position of flexion and pronation, while the triquetrum pulls the lunate into the triquetrum’s preferred position of extension given the intact lunotriquetral ligament. Additionally, the lunate’s configuration with a narrower dorsum and volarly inclined radial joint surface plays a role. Volar intercalated segment instability (VISI) describes the pattern of lunate flexion with disruption of the lunotriquetral ligament; the lunate is pulled into flexion with the scaphoid while the triquetrum falls into its normal tendency to extend. The dorsal radiocarpal ligament has been implicated as well in VISI pattern deformity.

Answer 56

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 57

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 58

The correct response is Option E. Operative planning for surgical treatment of basal thumb osteoarthritis requires not only careful history, physical examination, and radiographic examination of the basal thumb joint, but also the scaphotrapeziotrapezoid (STT) joint, the carpal tunnel, and the thumb metacarpophalangeal (MP) joint. Persistent arthritic symptoms following treatment of the basal thumb joint are often due to unrecognized STT arthritis, and many patients will have carpal tunnel syndrome concomitant with basal thumb arthritis; thus, it is important to evaluate for these pathologies to avoid persistent symptoms following surgery. The MP joint must be evaluated for collapse, or hyperextension, particularly with pinch prior to operative treatment. Failure to correct MP hyperextension, particularly that beyond 30 degrees, may lead to persistent pain and progressive collapse of the thumb. The scapholunate, lunotriquetral, thumb interphalangeal, and radioscaphoid joints are not associated with basal thumb arthritis or its treatment.

Answer 59

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 60

The correct response is Option C. This patient has early-stage scapholunate advanced collapse (SLAC) wrist. SLAC wrist is generally categorized by the Watson classification, which is a descriptive classification but also helps determine management options. The Watson classification is as follows: Stage I: Arthritis between scaphoid and radial styloid Stage II: Arthritis between scaphoid and entire scaphoid facet of the radius Stage III: Arthritis between capitate and lunate While original Watson classification describes preservation of radiolunate joint in all stages of SLAC wrist, subsequent description by other surgeons of pancarpal arthritis (stage IV) observed rare cases in which the radiolunate joint is affected. The radioulnar joint is not affected by SLAC wrist.

Answer 61

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 62

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 63

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 64

The correct response is Option A. The descending genicular artery supplies the medial femoral condyle flap. The descending genicular artery is a branch of the superficial femoral artery. This corticoperiosteal flap has been used with increasing frequency for small bony defects and the treatment of nonunion. A cutaneous component can also be harvested based on a saphenous artery branch. The anterolateral thigh flap is based off the lateral femoral circumflex artery perforators. The gracilis muscle flap is based off vessels from the medial circumflex femoral artery; perforator flaps can also be designed based off this vascular system. The profunda femoris supplies the posterior thigh flap. The peroneal artery provides the vascular supply to the fibula flap.

Answer 65

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 66

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 67

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 68

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 69

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 70

Correct Answer: B. Scaphoidectomy with four-corner fusion. The patient has scapholunate advanced collapse (SLAC) wrist with both radiocarpal and intercarpal arthritis, specifically involving the radioscaphoid and capitolunate articulations. Classification of advanced scapholunate collapse is broken down into 4 stages: -Stage I demonstrates radial styloid degenerative changes -Stage II is represented by degenerative changes that involve the scaphoid fossa and the styloid -Stage III has lunocapitate degenerative changes -Stage IV is the last, indicated by pancarpal arthritis (This is somewhat controversial because some surgeons do not believe that advanced scapholunate collapse will result in pancarpal arthritis.) Nevertheless, per the classical description, the radiolunate facet is always spared of arthrosis in scapholunate advanced collapse. However, results from recent studies have reported radiolunate arthrosis in up to 80% of patients. A stage IV SLAC has been described that includes pancarpal arthritis. In the treatment of SLAC wrist, scaphoidectomy eliminates the arthritic radioscaphoid articulation, while fusion of the capitate, hamate, lunate, and triquetrum bones addresses intercarpal capitolunate arthritis. This limited wrist fusion allows some degree of wrist motion. Arthrodesis of the radiolunate joint is used to prevent ulnar translation of the carpus in cases of radiocarpal arthritis, such as in rheumatoid arthritis. However, this approach does not address the issues of radioscaphoid or capitolunate arthritis. Proximal row carpectomy (PRC) is another treatment option for SLAC wrist, offering an alternative to scaphoidectomy and four-corner fusion in some cases. However, PRC is not optimal when capitolunate (midcarpal) arthritis is present, as the postoperative articulation between the capitate and the radius retains an arthritic joint surface. While osteochondral resurfacing of the arthritic capitate head has been proposed, it remains a controversial procedure. Silicone wrist arthroplasty can preserve some motion and decrease pain in wrist arthritis, but it is generally reserved for low-demand patients (e.g., those with rheumatoid arthritis). This approach is not suitable for manual laborers, as excessive force can lead to implant failure. Total wrist arthrodesis effectively relieves wrist pain caused by arthritis but sacrifices wrist motion. It is a good option for pancarpal arthritis and provides pain relief in high-demand wrists, though it does not preserve motion. Ligament reconstruction is contraindicated in the presence of arthritis or SLAC wrist. Treatment and Management The treatment of Scapholunate Advanced Collapse (SLAC) wrist is complex and often unpredictable. Nonoperative treatment may include: Nonsteroidal anti-inflammatory drugs (NSAIDs) Wrist splints Corticosteroid injections (for mild disease) Surgical management options include: Radial styloidectomy Proximal row carpectomy (PRC) Scaphoid excision and four-corner fusion Total wrist arthrodesis Wrist arthroplasty Stage-Wise Surgical Treatment Options Stage I SLAC Wrist Radial styloidectomy and scaphoid stabilization procedures PIN (posterior interosseous nerve) and AIN (anterior interosseous nerve) denervation Stage II SLAC Wrist Proximal row carpectomy (PRC) PRC is indicated for Stage II SLAC wrist but is contraindicated in Stage III due to the presence of capitolunate arthritis. Performing a PRC in cases of Stage III deformity often results in inferior outcomes due to the involvement of the capitolunate articulation. Stage III SLAC Wrist Scaphoid excision and four-corner fusion This procedure provides reliable and positive outcomes for patients with debilitating Stage II or Stage III SLAC wrist deformity. Long-term outcomes are equivalent to PRC for Stage II SLAC wrist deformity. Wrist fusion Indicated for Stage III SLAC wrist or pancarpal arthritis (Stage IV SLAC). While wrist fusion procedures effectively relieve pain, they compromise wrist motion compared to scaphoid excision and four-corner fusion. Scaphoid excision and four-corner fusion preserve wrist motion through the lunate/distal radius articulation at the lunate fossa, offering functional advantages. References Daar DA, Shah A, Mirrer JT, Thanik V, Hacquebord J. Proximal row carpectomy versus four-corner arthrodesis for the treatment of scapholunate advanced collapse/scaphoid nonunion advanced collapse wrist: a cost-utility analysis. Plast Reconstr Surg. 2019;143(5):1432-1445. doi:10.1097/PRS.0000000000005558 Saltzman BM, Frank JM, Slikker W, Fernandez JJ, Cohen MS, Wysocki RW. Clinical outcomes of proximal row carpectomy versus four-corner arthrodesis for post-traumatic wrist arthropathy: a systematic review. J Hand Surg Eur Vol. 2015;40(5):450-457. doi:10.1177/1753193414554359 Wagner ER, De George BR. Intercarpal and radiocarpal arthritis. In: Weiss APC, Budoff JE, Calfee RP, et al., eds. The American Society for Surgery of the Hand Textbook of Hand and Upper Extremity Surgery. 2nd ed. American Society for Surgery of the Hand; 2019:519-544.

Answer 71

Correct Answer: D. Forearm and elbow x-ray studies to assess for a more proximal fracture and instability. The patient’s symptoms and history, including ulnar-sided wrist pain, limited supination, and a history of radial head excision following trauma, raise suspicion for an Essex-Lopresti injury. This injury involves distal radioulnar joint (DRUJ) instability, disruption of the interosseous membrane (IOM), and proximal radial migration due to previous trauma (Ulnar positive variance). • Forearm and elbow x-rays are essential to evaluate for proximal injuries, such as proximal radial migration and any associated fractures or joint instability. • Clenched-fist x-rays assess scapholunate ligament injuries, which are not the primary concern here. • Wrist CT can identify occult wrist fractures but would not address the possibility of proximal injury. • MR arthrogram might show TFCC injury but is invasive, not first-line, and unnecessary before ruling out proximal issues. • 30-degree supinated lateral x-ray is specific for metacarpal fractures, which are irrelevant in this scenario.

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Hand - Wrist ligament injuries and fractures Flashcards

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