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7. Hand and Wrist MCQs

Practice Set 69 of 266

This practice set contains high-yield board review questions covering key concepts in 7. Hand and Wrist. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1361

Topic: 7. Hand and Wrist

A 25-year-old construction worker lands on his outstretched hand in a fall. The position of his wrist at the time of impact causes a force that leads to hyperextension, ulnar deviation, and intercarpal supination. Radiographs are shown in Figures 48a and 48b. Management should consist of

. closed reduction and a long arm cast.
. closed reduction, percutaneous pin fixation, and a long arm cast.
. closed reduction and an external fixator.
. open reduction and internal fixation and soft-tissue repair.
. proximal row carpectomy.

Correct Answer & Explanation

. closed reduction and a long arm cast.

Explanation

DISCUSSION: Open reduction and internal fixation is the treatment of choice for accurate reduction of the disrupted intercarpal ligaments.  In addition, the displaced scaphoid fracture will require open reduction and internal fixation and possible bone grafting.  Closed reduction and long arm casting will not allow accurate reduction of the dislocated intracarpal intervals, and it is unlikely to allow accurate reduction of the scaphoid.  The maneuver required to effect closed reduction of a displaced scaphoid fracture will most likely cause the scaphoid lunate interval to displace.  Closed reduction with percutaneous pin fixation or with an external fixator is unable to effect anatomic reduction of the injury.  Proximal row carpectomy is used as a salvage procedure for a variety of degenerative and posttraumatic problems of the wrist.REFERENCES: Kozin SH: Perilunate injuries: Diagnosis and treatment.  J Am Acad Orthop Surg 1998;6:114-120.Herzberg G, Comtet JJ, Linscheid RL, Amadio PC, Cooney WP, Stalder J: Perilunate dislocations and fracture-dislocations: A multicenter study.  J Hand Surg Am 1993;18:768-779.Sotereanos DG, Mitsionis GJ, Ginnakopoulos PN, Tomaino MM, Herndon JH: Perilunate dislocation and fracture dislocation: A critical analysis of the volar-dorsal approach.  J Hand Surg Am 1997;22:49-56.

Question 1362

Topic: 7. Hand and Wrist

-Figure is the clinical photograph of a 70-year-old woman with squamous cell cancer on her thumb.Resection and reconstruction is planned and requires soft-tissue coverage. Thumb region coverage is best obtained with

. the Moberg flap.
. a third dorsal metacarpal artery flap.
. a first dorsal metacarpal artery flap.
. a full-thickness skin grafting.
. a reverse cross-finger flap from the index finger with full-thickness skin grafting.

Correct Answer & Explanation

. the Moberg flap.

Explanation

Question 1363

Topic: 7. Hand and Wrist
  • A 25 year-old amateur baseball player sustained a dorsal fracture-dislocation of the proximal interphalangeal joint of his long finger. He underwent closed reduction 3 hours ago. Examination reveals mild laxity of the radial collateral fragment involving 30% of the volar articular surface of the middle phalanx. Management should now include
. open reduction and internal fixation
. buddy taping to the adjacent index finger
. early motion with application of a dynamic banjo splint
. application of a cast with the hand in a “safe position” for 3 weeks.
. dorsal extension block splinting

Correct Answer & Explanation

. open reduction and internal fixation

Explanation

ORIF is most commonly used to treat displaced intrarticular, unstable, or unreducible injuries. Buddy taping is used for isolated volar plate injuries. Dynamic splints are used for volar dislocations in this presentation. Casting in the intrinsic plus position is falling out of favor for earlier range of motion options with PIP fracture dislocations.“Intra-articular fractures that involve the base of the middle phalanx are usually one of three types 1. Dorsal chip fracture 2. Volar lip fracture, usually combined with a dorsal dislocation of subluxation of the middle phalanx 3. Lateral chip fracture, representing avulsion of bone by the collateral ligament.” Kuczynski has suggested that the volar plate is less mobile in the PIP joint than it is in the MP joint.“What must always occur with dorsal dislocation, however, is rupture of the volar plate. According to Bowers, the plate is virtually always disrupted from its distal attachment into the base of the middle phalanx. This may with or without a small avulsion chip fracture.”If the fracture involves more than a third of the joint or is unstable then the PIP joint must be stabilized in a reduced position with early range of motion while restricting PIP hyperextension.The preferred method of treatment is dorsal extension block splinting for three weeks, then protected range of motion until united.

Question 1364

Topic: Nerve & Tendon

Figures 2a and 2b are the MR arthrograms of a 19-year-old college baseball pitcher who injured his throwing elbow during a game 5 days ago when he felt a pop. Immediately after the throw he reported significant discomfort with pitching and noted that he could not achieve his normal velocity or accuracy in location with his subsequent pitches. On further questioning, he admits to increasing medial elbow pain over the last few seasons with pitching. Examination reveals medial elbow swelling and somewhat diffuse tenderness to palpation medially. Valgus stress at 30 degrees of flexion and resisted wrist flexion produced discomfort. He notes some tingling in his fourth and fifth fingers but Tinel's test posterior to the medial epicondyle is unremarkable. Radiographs of the elbow show no fracture. Because the patient wishes to return to competitive throwing, what is the next step in management? Review Topic

. Ulnar nerve transposition
. Ulnar collateral ligament reconstruction
. Long arm cast for a medial epicondyle fracture
. Open reduction and internal fixation of the medial epicondyle
. Elbow arthroscopy and excision of a posteromedial olecranon osteophyte

Correct Answer & Explanation

. Ulnar nerve transposition

Explanation

This high level throwing athlete has a full-thickness injury to the ulnar collateral ligament and is most likely to be able to return to competitive throwing with an ulnar collateral ligament reconstruction. There is no radiographic evidence of a medial epicondyle fracture. The clinical presentation and lack of a posteromedial olecranon osteophyte makes valgus extension overload unlikely, and therefore, makes arthroscopic osteophyte excision a suboptimal choice. Whereas ulnar nerve pathology can coexist with an ulnar collateral ligament injury, isolated ulnar nerve transposition without addressing the ligament injury is not warranted in this patient. Initial nonsurgical management with activity modification and physical therapy is appropriate for partial-thickness injury to the ulnar collateral ligament in a nonthrowing athlete, and in athletes whose sporting activity places them at low risk.

Question 1365

Topic: 7. Hand and Wrist

The inheritance of the deformity shown in Figure 1 is most commonly

. autosomal-recessive.
. autosomal-dominant.
. x-linked dominant.
. mitochondrial.
. sporadic.

Correct Answer & Explanation

. autosomal-recessive.

Explanation

DISCUSSION: Cleft hand and cleft foot malformations are commonly inherited as autosomal-dominant traits and are associated with a number of syndromes.  An autosomal-recessive and an x-linked inheritance pattern have also been described, but these are much less common and are usually atypical.  In the common autosomal-dominant condition, nearly one third of the known carriers of the gene show no hand or foot abnormalities.  This is known as reduced penetrance.  The disorder may be variably expressed; affected family members often exhibit a range from mild abnormalities in one limb only to severe anomalies in four limbs.  Variable expressivity and reduced penetrance can cause difficulty in counseling families regarding future offspring in an affected family.  Many patients have a cleft hand that may be caused by the split-hand, split-foot gene (SHFM1) localized on chromosome 7q21.REFERENCE: Kay SPJ: Cleft hand, in Green DP (ed): Green’s Operative Hand Surgery. Philadelphia, Pa, Churchill Livingston, 1999, pp 402-414.

Question 1366

Topic: 7. Hand and Wrist

An ulnar nerve palsy at the level of the wrist is typically associated with deficits in the palmaris brevis, the hypothenar muscles, and what other groups of muscles?

. Volar interossei, adductor pollicis, and the deep head of the flexor pollicis brevis
. Dorsal interossei, adductor pollicis, and the deep head of the flexor pollicis brevis
. Dorsal interossei, adductor pollicis, and both heads of the flexor pollicis brevis
. All of the interossei and the abductor pollicis brevis
. All of the interossei, adductor pollicis, and the deep head of the flexor pollicis brevis

Correct Answer & Explanation

. Volar interossei, adductor pollicis, and the deep head of the flexor pollicis brevis

Explanation

DISCUSSION: The intrinsic muscles innervated by the ulnar nerve include the palmaris brevis, hypothenar muscles, all of the interossei, adductor pollicis, and the deep head of the flexor pollicis brevis.  The superficial head of the flexor pollicis brevis is innervated by themedian nerve.REFERENCES: Goldfarb CA, Stern PJ: Low ulnar nerve palsy.  JASSH 2003;3:14-26.Omer G: Ulnar nerve palsy, in Green DP, Hotchkiss R, Pederson W (eds): Green’s Operative Hand Surgery, ed 4.  Philadelphia, PA, Churchill Livingstone, 1999, pp 1526-1541.

Question 1367

Topic: Nerve & Tendon

preservation of the radioscaphocapitate ligament, the most radial of the palmar extrinsic ligaments, which prevents ulnar subluxation after proximal row carpectomy.

. The arrows in the axial T1-weighted MRI scan shown in Figure 25 show which of the following structures?
. Ulnar artery and accompanying vein
. Deep and superficial branches of the ulnar nerve
. Radial and ulnar digital nerves to the little finger
. Palmar cutaneous and thenar motor branch of the median nerve
. Dorsal cutaneous branch of the ulnar nerve and common digital artery to the fourth web

Correct Answer & Explanation

. The arrows in the axial T1-weighted MRI scan shown in Figure 25 show which of the following structures?

Explanation

The arrows in the figure show the deep branch of the ulnar nerve (more radial) and the superficial branch of the ulnar nerve within Guyon’s canal. Guyon’s canal is approximately 4 cm long beginning at the proximal extent of the transverse carpal ligament and ends at the aponeurotic arch of the hypothenar muscles. Many structures comprise the boundaries of Guyon’s canal. The floor, for example, consists of the transverse carpal ligament, the pisohamate and pisometacarpal ligaments, and the opponens digiti minimi. Within Guyon’s canal, the ulnar nerve bifurcates into the superficial and deep branches. The ulnar artery is immediately adjacent and radial to the ulnar nerve. The median nerve is visualized within the carpal tunnel, and the palmar cutaneous branch is more radial to Guyon’s canal and volar to the carpal tunnel. The radial and ulnar digital nerves to the little finger are branches off of the superficial branch of the ulnar nerve distal to its emergence from Guyon’s canal. The ulnar artery is the round structure located radial to the branches of the ulnar nerve within Guyon’s canal. Adjacent to the ulnar artery are two small veins. The dorsal cutaneous branch of the ulnar nerve branches from the ulnar nerve in the distal forearm, well proximal to Guyon’s canal. The common digital artery to the fourth web branches from the superficial palmar arch distal to Guyon’s canal. The hook of the hamate is clearly seen in the figure, orienting the observer to the ulnar side of the wristA 37-year-old patient with type I diabetes mellitus has a flexor tenosynovitis of the thumb flexor tendon sheath following a kitchen knife puncture wound to the volar aspect of the thumb. Left unattended, this infection will likely first spread proximally creating an abscess in which of the following spaces of the palm?Central spaceHypothenar spaceCarpal tunnelPosterior adductor spaceThenar spaceCORRECT ANSWER: 5Flexor tenosynovitis of the thumb flexor tendon sheath can spread proximally and form an abscess within the thenar space of the palm. The flexor pollicis longus tendon does not pass through the central space of the palm or the hypothenar space of the palm. The flexor pollicis longus tendon does pass through the carpal tunnel, but this is not a palmar space. The three palmar spaces include the hypothenar space, the thenar space, and the central space. The posterior adductor space would likely only be involved secondarily after spread from a thenar space infection.New painful paresthesias near the site of the incision after an ulnar nerve transposition is the result of injury to what nerve?Medial antebrachial cutaneousLateral antebrachial cutaneousPosterior antebrachial cutaneousMedial brachial cutaneousDorsal antebrachial cutaneousBranches of the medial antebrachial cutaneous nerve can often be identified during routine ulnar nerve surgery crossing the medial aspect of the elbow. It should be preserved to avoid development of painful paresthesias.A 21-year-old man who was injured in a snowboarding accident 18 months ago now reports wrist pain. An MRI scan is shown in Figure

Question 1368

Topic: 7. Hand and Wrist

Figures 42a and 42b shows the radiographs of a 20-year-old man who sustained a hyperextension injury to his little finger. Multiple attempts at closed reduction have been unsuccessful. Management should now consist of

. external traction.
. open reduction and internal stabilization.
. repeat closed reduction under general anesthesia.
. open reduction.
. percutaneous pin fixation in the current position.

Correct Answer & Explanation

. external traction.

Explanation

DISCUSSION: The radiographs show a complex dislocation of the little finger metacarpophalangeal joint.  This is characterized by obvious dislocation on the AP and lateral views and a type of bayonet apposition best visualized on the lateral view.  Irreducibility of this injury is caused by displacement of the volar plate that has been traumatically avulsed from its origin on the metacarpal, with subsequent displacement into the metacarpophalangeal joint.  This abnormal position of the volar plate causes irreducibility that can be corrected only by open reduction.  This can be effected either by dorsal or palmar approaches.REFERENCES: Stern PJ: Fractures of the metacarpals and phalanges, in Green DP, Hotchkiss RN, Pederson WC (eds): Green’s Operative Hand Surgery, ed 4.  Philadelphia, PA, 1999,pp 711-771.Becton JL, Christian JD Jr, Goodwin HN, Jackson JG III: A simplified technique for treating the complex dislocation of the index metacarpophalangeal joint.  J Bone Joint Surg Am 1975;57:698-700.Green DP, Terry GC: Complex dislocation of the metacarpophalangeal joint: Correlative pathological anatomy.  J Bone Joint Surg Am 1973;55:1480-1486.

Question 1369

Topic: 7. Hand and Wrist

Figures 45a and 45b show the radiographs of a 40-year-old woman with rheumatoid arthritis who is unable to straighten her ring and little fingers. Examination reveals that the fingers can be passively corrected, but she is unable to actively maintain the fingers in extension. Management should consist of

. radial head resection.
. dynamic splinting.
. metacarpophalangeal arthroplasties.
. total wrist arthrodesis with a flexor digitorum sublimis to extensor digitorum communis transfer.
. distal ulnar resection with an extensor indius proprius to extensor digitorum communis transfer.

Correct Answer & Explanation

. radial head resection.

Explanation

DISCUSSION: The patient has extensor tendon ruptures at the level of the wrist that are the result of synovitis at the distal radioulnar joint (Vaughn-Jackson syndrome).  Extensor indius proprius transfer appropriately matches strength and excursion of the ruptured extensor digiti quinti and extensor digitorum communis tendons.  An extensor tenosynovectomy with distal radioulnar joint resection decreases the synovitis, which if left untreated may cause additional tendon ruptures.  Radial head resection is used for posterior interosseous nerve compression secondary to radial head synovitis, and in this patient only two fingers are involved, which rules out this diagnosis.  Dynamic splinting is not indicated for ruptured tendons.  Metacarpophalangeal arthroplasties and imbrication of the sagittal bands are used for metacarpophalangeal arthritis and extensor tendon subluxation.  If this was the problem, the patient should be able to maintain the fingers in extension after they are passively extended.  Total wrist arthrodesis prevents the tenodesis effect, thus limiting effective tendon excursion and making the proposed transfer less effective.REFERENCES: Feldon P, Terrono AL, Nalebuff EA, et al: Rheumatoid arthritis and other connective tissue diseases: Tendon ruptures, in Green DP, Hotchkiss RN, Pederson WC (eds): Green’s Operative Hand Surgery, ed 4.  New York, NY, Churchill Livingstone, 1999,pp 1669-1684.Moore JR, Weiland AJ, Valdata L: Tendon ruptures in the rheumatoid hand:  Analysis of treatment and functional results in 60 patients.  J Hand Surg Am 1987;12:9-14.Leslie BM: Rheumatoid extensor tendon ruptures.  Hand Clin 1989;5:191-202.

Question 1370

Topic: 7. Hand and Wrist
A positive Froment sign indicates weakness of which of the following muscles?
. First dorsal interosseous
. Adductor pollicis
. Opponens pollicis
. Flexor pollicis brevis
. Abductor pollicis longus

Correct Answer & Explanation

. Adductor pollicis

Explanation

DISCUSSION: Thumb adduction is powered by the adductor pollicis (ulnar nerve). Testing involves having the patient forcibly hold a piece of paper between the thumb and radial side of the index proximal phalanx. When this muscle is weak or nonfunctioning, the thumb interphalangeal joint flexes with this maneuver, resulting in a positive Froment sign. The paper is held by action of the thumb flexion (flexor pollicis longus and flexor pollicis brevis; median innervated). REFERENCE: Burton RI: The Hand: Examination and Diagnosis. Chicago, IL, American Society for Surgery of the Hand, 1978, pp 26-27.

Question 1371

Topic: 7. Hand and Wrist
At which joint do degenerative changes occur first in a patient with chronic, untreated scapholunate dissociation?
. Radioscaphoid
. Radiolunate
. Scapholunate
. Capitolunate

Correct Answer & Explanation

. Radioscaphoid

Explanation

EXPLANATION: Stage I of scapholunate advanced collapse (SLAC) is characterized by the presence of radioscaphoid arthritis. A predictable pattern exists of the progression of degenerative changes for SLAC wrist, including stage I (radial styloid involvement at the scaphoid fossa), stage II (scaphoid and entire scaphoid facet involvement), stage III (degeneration between the capitate and lunate), and stage IV (pancarpal involvement). The radiolunate joint is often spared.

Question 1372

Topic: 7. Hand and Wrist
Spontaneous rupture of the extensor pollicis longus tendon is most frequently associated with which of the following scenarios?
. Nondisplaced distal radius fracture
. Nondisplaced Rolando fracture
. Second metacarpal base fracture
. Boxer's fracture
. Nondisplaced radial styloid fracture

Correct Answer & Explanation

. Nondisplaced distal radius fracture

Explanation

DISCUSSION: Rupture of the extensor pollicis longus (EPL) tendon after nonoperative treatment for a distal radius fracture occurs with a 0.3-3% incidence. The causes of EPL rupture include mechanical irritation, attrition, and vascular impairment leading to delayed rupture. Synovitis of the extensor carpi radialis due to repetitive use may invade the EPL tendon and lead to rupture. Recommended treatment in the pre-rupture setting includes a third dorsal compartment release with or without an extensor retinacular patch graft. Palmaris longus graft or a transfer from the extensor indicis proprius to the EPL tendon are reasonable treatment options. Results of all treatments seem to be clinically satisfactory. The referenced article by Gelb is a review of the etiology and treatment of this injury. He reviews the above discussion and findings.

Question 1373

Topic: Nerve & Tendon
  • A patient sustains a closed dorsal dislocation of the proximal interphalangeal joint of the middle finger without an associated fracture. Closed treatment results in a cocentric stable reduction. The finger is not immobilized. Which of the following conditions may appear 1 year later?
. Triggering
. Lateral instability
. Swan-neck deformity
. Boutonniere deformity
. Loss of distal interphalangeal joint flexion

Correct Answer & Explanation

. Triggering

Explanation

Swan neck deformity describes a posture of the finger in which the PIP joint is hyperextended and the DIP joint is flexed. Initially this is a dynamic imbalance that occurs when a patient attempts maximal digital extension. This dynamic finger imbalance can progress to a static deformity. There are many etiologies for SND and include injuries resulting in volar plate laxity (e.g. dorsal dislocation of the PIP.), spastic conditions such as stroke & CP, RA, fractures of the middle and proximal phx healed in extension.Question 199 -Examination of a 3-year-old boy who slammed his finger in a door 3 months ago reveals 0 to 40 degrees of proximal interphalangeal joint motion. Radiographs are shown in Figures 47a and 47b. Management should consist ofVolar osteotomyObservation onlyFlexor tenolysisVolar plate arthoplastyA hinged distraction external fixatorSubcondylar fractures of the proximal and middle phalynx occur at the neck of the phalynx, usually as a result of a crush injury, and almost exclusively in the pediatric age group. The distal fragment rotates dorsally and the degree of displacement may be misjudged if a true lateral is not obtained. If malunion occurs there is block to flexion. Subcondylar fossa reconstruction by removal of bone through a palmar approach removes this boney block.

Question 1374

Topic: 7. Hand and Wrist
A 44-year-old man sustains the injury shown in Figures 1 through 3. What is the most appropriate treatment?
. Reduction and internal fixation
. Closed reduction and splinting alone
. Carpometacarpal arthrodesis
. Carpometacarpal (CMC) joint suspension arthroplasty

Correct Answer & Explanation

. Reduction and internal fixation

Explanation

Reduction, either open or closed, with internal fixation (pinning) is the recommended treatment for the majority of these injuries. Closed reduction with pinning is most often performed for acute injuries. Open reduction with pinning is performed for those injuries that cannot be reduced by closed means or those with a delayed presentation. Four cases of successful closed reduction and splinting, all performed upon presentation in the emergency department, have been described by Storken and associates, but the authors note that their review of three prior reports uncovered cases of secondary dislocation, which required surgical stabilization. One of the dislocations occurred 4 months after the reduction. They assert that an indication for primary ORIF is a CMC dislocation associated with major fractures. Primary arthrodesis can be considered in cases with severe intra-articular comminution, but this procedure substantially limits the ability of the hand to increase and decrease the transverse metacarpal arch, which is an important functional movement. It can also lead to osteoarthritis of the triquetrohamate joint. Suspension arthroplasty has been described for old fracture-dislocations of the fifth CMC joint, using a partial slip of the extensor carpi ulnaris.

Question 1375

Topic: Wrist & Carpus

A prospective randomized trial is conducted to test the efficacy of Vitamin C versus placebo in treating patients who develop chronic regional pain syndrome (CRPS) after distal radius fractures. At first follow-up, the rates of CRPS are 1% and 9% in the study and placebo group, respectively. Which statistical test is most appropriate to determine significance?

. Single factor analysis of variance
. Chi-square test
. Student t-test
. Mann-Whitney rank sum test
. Wilcoxon rank sum test

Correct Answer & Explanation

. Single factor analysis of variance

Explanation

In the study provided, we need to determine whether distributions of categorical variables differ from one another. The appropriate study is the chi-square test.Data can be classified as numerical (continuous) or categorical (proportional). Responses to such questions as "What is your major?" or Do you own a car?" are categorical because they yield data such as "biology" or "no." In contrast, responses to such questions as "How tall are you?" or "What is your G.P.A.?" are numerical. When comparing two independent means from numeric data, a t-test is performed. However, if categorical data is being compared, the chi-square test will determine if the proportions are really different.Kocher et al. review basic clinical epidemiology and biostatistics relevant to orthopaedic surgery. Amongst other things, they describe that data can be summarized in terms of measures of central tendency, such as mean, median, and mode, and interms of measures of dispersion, such as range, standard deviation, and percentiles. Illustration A shows an algorithm for determining which test to use for varying data.Incorrect Answers:

Question 1376

Topic: 7. Hand and Wrist
Figures 1 through 3 demonstrate the radiographs obtained from a 25-year-old man who injured his right hand by punching a wall 3 weeks earlier. He notes pain and deformity about the ulnar aspect of his hand. The best treatment option is:
. closed reduction and cast immobilization.
. open reduction and internal fixation (ORIF).
. arthrodesis.
. resection arthroplasty.

Correct Answer & Explanation

. open reduction and internal fixation (ORIF).

Explanation

The initial radiographs reveal a fourth and fifth carpometacarpal (CMC) joint fracture dislocation. Because the patient presented in a delayed fashion (3 weeks after injury), open reduction with internal fixation is required. Closed reduction and casting are not appropriate for delayed presentations of this injury.

Question 1377

Topic: 7. Hand and Wrist
Which of the following is an advantage of computer-assisted navigation used to place medullary nail interlocking screws compared to a freehand technique?
. Reduced fluoroscopy time
. More reliable placement of interlocking screws through the nail
. Reduced procedure time
. Increased quality of fluoroscopic images
. Improved accuracy of screw length

Correct Answer & Explanation

. Reduced fluoroscopy time

Explanation

Computer-assisted navigation has been shown to reduce radiation exposure for surgeons when performing interlocking of medullary nails compared to the freehand technique. Studies have shown that fluoroscopy time and the number of fluoroscopy images are significantly less when using computer-guided systems.

Question 1378

Topic: 7. Hand and Wrist
Figure 1 is the radiograph of a 22-year-old man who underwent an open reduction and pinning of a perilunate dislocation 10 weeks ago. The hardware has been removed. What is the best next step?
. Observation
. Vascularized bone grafting to the lunate
. Core decompression of the radius and ulna
. Immobilization

Correct Answer & Explanation

. Observation

Explanation

Lunate or perilunate dislocations are usually treated with open reduction and internal fixation through a dorsal or combined dorsal and volar approach. A high index of suspicion is necessary when treating patients who sustain multiple trauma because as many as 25% of lunate or perilunate dislocations are missed initially. The radiodense appearance of the lunate seen in Figure 1 is an example of transient ischemia of the lunate that can occur following treatment of lunate and perilunate dislocations. It has been reported in up to 12.5% of cases. This usually is seen between 1 and 4 months post-injury with a relative radiodensity of the lunate. This appearance of the lunate should not be overtreated and usually is a benign self-limiting event. Surgery is not indicated at this time; the incorrect responses are treatment options for Kienböck disease. Treatment of the lunate or perilunate dislocation involves initial gentle closed reduction followed by open reduction, ligamentous and bone repair, and internal fixation. Median nerve dysfunction is common, and a simultaneous carpal tunnel release is often performed. Early treatment seems to produce better results, but good results have been reported when treatment is delayed for up to 6 months. The many questions regarding treatment of this problem involve the use of capsulodesis to supplement intercarpal ligament repair, repair/stabilization of the lunotriquetral interval vs no treatment of that articulation, and intercarpal fixation techniques. In delayed cases, proximal row carpectomy when the head of the capitate is intact and total wrist fusion if there are degenerative changes have been used. Chondral injuries are common, may not be recognized on radiographs, and may negatively affect long-term outcomes. Even when treatment is optimal, this injury is associated with a guarded prognosis and possible permanent partial loss of wrist motion and grip strength. At 10-year follow-up, radiographs will often demonstrate degenerative changes, but these changes do not always substantially negatively affect hand function.

Question 1379

Topic: 7. Hand and Wrist
Compared with percutaneous pinning with Kirschner wires (K-wires), the treatment of metacarpal neck fractures with cannulated intramedullary screws is associated with
. increased rates of soft-tissue infection.
. greater initial construct stiffness and peak load until failure.
. a slower return of digital range of motion.
. an earlier time to bony union.

Correct Answer & Explanation

. greater initial construct stiffness and peak load until failure.

Explanation

In a biomechanical study, headless compression screws showed superior load to failure, higher three-point bending strength, and greater strength in axial loading compared with percutaneous K-wire fixation for metacarpal neck fractures. Headless compression screws provide greater initial stability to allow earlier motion in the postoperative period. No data comparing infection rates between the two methods of fixation are available; however, it is assumed that K-wires placed outside of the skin would have increased rates of infection. Neither fixation method would increase the time to healing.

Question 1380

Topic: 7. Hand and Wrist
The patient in Figure 55 is actively attempting to make a fist. This clinical scenario suggests which of the following anatomic lesions?
. Median nerve lesion in the arm
. Radial nerve lesion in the arm
. Anterior interosseous nerve syndrome
. Posterior interosseous nerve syndrome
. Median neuropathy at the wrist

Correct Answer & Explanation

. Median nerve lesion in the arm

Explanation

DISCUSSION: The clinical presentation is characteristic of a high median nerve palsy. When trying to make a fist, the patient is unable to flex the thumb and index fingers due to paralysis of flexion of the distal interphalangeal joint of the thumb and the distal and proximal interphalangeal joints of the index finger. This hand attitude differs from the anterior interosseous nerve lesion in which loss of distal interphalangeal joint flexion is seen in the thumb, index, and middle fingers. Posterior interosseous nerve syndrome presents with dropped fingers at the metacarpophalangeal joints with wrist extension in radial deviation. Wrist and finger drop is the typical posture of patients with radial nerve lesions. REFERENCE: Kline DG, Hudson AR: Nerve Injuries: Operative Results for Major Nerve Injuries, Entrapments and Tumors. Philadelphia, PA, WB Saunders, 1995, p 189.

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