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7. Hand and Wrist MCQs

Practice Set 31 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 601

Topic: 7. Hand and Wrist
A 28-year-old patient undergoes ORIF for a Monteggia fracture. Postoperatively, he cannot extend his thumb or the metacarpophalangeal joints of his fingers, but wrist extension is preserved with radial deviation. Which nerve was most likely injured?
. Anterior interosseous nerve
. Median nerve
. Posterior interosseous nerve
. Superficial radial nerve
. Ulnar nerve

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

The posterior interosseous nerve (PIN) is highly susceptible to injury in Monteggia fractures (especially Bado types I and III). PIN palsy causes weakness in digit and thumb extension, while wrist extension is preserved but deviates radially due to an intact ECRL (innervated by the radial nerve proper).

Question 602

Topic: 7. Hand and Wrist

During the surgical approach for a perilunate dislocation, the surgeon addresses the 'Space of Poirier'. This area of capsular weakness is located between which two carpal bones?

. Scaphoid and Lunate
. Lunate and Capitate
. Lunate and Triquetrum
. Capitate and Hamate
. Scaphoid and Trapezium

Correct Answer & Explanation

. Lunate and Capitate

Explanation

The Space of Poirier is a central weak area in the volar wrist capsule located directly at the lunate-capitate articulation. It allows the capitate to dislocate dorsally in relation to the lunate during perilunate injuries.

Question 603

Topic: 7. Hand and Wrist

A 35-year-old male presents with a transscaphoid perilunate dislocation. What is the most appropriate surgical management sequence to ensure optimal carpal alignment?

. ORIF of the scaphoid followed by lunotriquetral repair
. Closed reduction and percutaneous pinning of the SL interval
. Proximal row carpectomy
. Lunate reduction, lunotriquetral repair, then scaphoid ORIF
. Scaphoid ORIF, lunate reduction, followed by SL and LT repair

Correct Answer & Explanation

. Scaphoid ORIF, lunate reduction, followed by SL and LT repair

Explanation

In transscaphoid perilunate fracture-dislocations, restoring the bony architecture of the radial column (scaphoid ORIF) is the priority. This provides a stable anatomic foundation for the accurate reduction of the lunate and subsequent repair of the lunotriquetral and other injured ligaments.

Question 604

Topic: Wrist & Carpus
According to Mayfield's stages of perilunate instability, a stage III injury is characterized by the disruption of which of the following ligaments?
. Scapholunate interosseous ligament
. Volar radiolunate ligament
. Lunotriquetral interosseous ligament
. Dorsal radiocarpal ligament
. Ulnar collateral ligament

Correct Answer & Explanation

. Lunotriquetral interosseous ligament

Explanation

Mayfield stage I involves the scapholunate ligament, and stage II involves capsular disruption allowing dorsal capitate dislocation. Stage III involves disruption of the lunotriquetral interosseous ligament, separating the lunate from the triquetrum.

Question 605

Topic: 7. Hand and Wrist

A 22-year-old gymnast sustains a pure perilunate dislocation. She undergoes a combined dorsal and volar open approach for reduction and repair. Which of the following is the primary advantage of adding the volar approach to the standard dorsal approach?

. Direct repair of the scapholunate interosseous ligament
. Repair of the dorsal radiocarpal ligament
. Decompression of the carpal tunnel and repair of the rent in the volar capsule
. Better visualization for percutaneous pinning of the midcarpal joint
. Reduction of the capitate into the lunate facet

Correct Answer & Explanation

. Decompression of the carpal tunnel and repair of the rent in the volar capsule

Explanation

While a dorsal approach is essential for repairing the interosseous ligaments (SL and LT), adding a volar approach allows for crucial carpal tunnel decompression. It also facilitates the direct repair of the volar capsular rent (Space of Poirier), optimizing volar stability.

Question 606

Topic: 7. Hand and Wrist

You are evaluating a 28-year-old male with a suspected perilunate injury. The lateral radiograph demonstrates a 'spilled teacup' sign. According to Mayfield's progressive sequence, what anatomical structure must completely fail to allow this specific displacement?

. Volar radiolunate ligament
. Dorsal radiocarpal ligament
. Radioscaphocapitate ligament
. Triangular fibrocartilage complex
. Scaphotrapezial ligament

Correct Answer & Explanation

. Dorsal radiocarpal ligament

Explanation

A 'spilled teacup' sign on a lateral radiograph indicates a lunate dislocation (Mayfield Stage IV). This final stage of instability occurs when the dorsal radiocarpal ligament completely fails, allowing the lunate to spill volarly into the carpal tunnel.

Question 607

Topic: 7. Hand and Wrist

In a Mayfield Stage IV perilunate injury resulting in a volar lunate dislocation, which key ligamentous structure remains intact and tethers the lunate to the radius, acting as a hinge for its displacement?

. Dorsal radiocarpal ligament
. Short radiolunate ligament
. Scapholunate interosseous ligament
. Lunotriquetral interosseous ligament
. Radioscaphocapitate ligament

Correct Answer & Explanation

. Short radiolunate ligament

Explanation

In a Mayfield Stage IV injury, the lunate is extruded volarly into the carpal tunnel. The strong palmar short radiolunate ligament typically remains intact, tethering the lunate to the distal radius and preventing complete free-floating extrusion.

Question 608

Topic: 7. Hand and Wrist

When performing a combined dorsal and volar approach for the surgical treatment of a perilunate dislocation, the dorsal approach typically utilizes the interval between which extensor compartments to access the radiocarpal joint?

. Between the 1st and 2nd compartments
. Between the 2nd and 3rd compartments
. Between the 3rd and 4th compartments
. Between the 4th and 5th compartments
. Between the 5th and 6th compartments

Correct Answer & Explanation

. Between the 2nd and 3rd compartments

Explanation

The dorsal approach to the wrist for perilunate dislocations typically utilizes the interval between the 3rd (extensor pollicis longus) and 4th (extensor digitorum communis) dorsal extensor compartments. This provides excellent exposure of the carpus while preserving the capsular ligaments for repair.

Question 609

Topic: 7. Hand and Wrist

A 30-year-old patient with a lunate dislocation presents with dense numbness in the median nerve distribution. A successful closed reduction is performed in the emergency department, but the patient's median nerve symptoms remain severe and unchanged after 2 hours. What is the most appropriate next step?

. Reassurance and observation for an additional 24 hours
. Corticosteroid injection into the carpal tunnel
. Emergent open reduction and carpal tunnel release
. Application of a rigid short arm cast in wrist flexion
. MRI of the wrist to evaluate the median nerve

Correct Answer & Explanation

. Emergent open reduction and carpal tunnel release

Explanation

Acute median neuropathy that does not resolve rapidly after closed reduction of a perilunate or lunate dislocation indicates ongoing nerve compression. This requires emergent carpal tunnel release and simultaneous open reduction and internal fixation.

Question 610

Topic: 7. Hand and Wrist

When evaluating a PA radiograph of a normal wrist, Gilula's arcs are critical for identifying subtle perilunate instability. Gilula's second arc traces the contour of which of the following articular boundaries?

. Proximal articular surfaces of the scaphoid, lunate, and triquetrum
. Distal articular surfaces of the scaphoid, lunate, and triquetrum
. Proximal articular surfaces of the capitate and hamate
. Distal articular surfaces of the capitate and hamate
. The articulation between the distal radius and the proximal carpal row

Correct Answer & Explanation

. Distal articular surfaces of the scaphoid, lunate, and triquetrum

Explanation

Gilula's second arc traces the distal concave articular surfaces of the proximal carpal row (scaphoid, lunate, and triquetrum). Disruption of this arc is a reliable radiographic indicator of a perilunate dislocation or major carpal derangement.

Question 611

Topic: Wrist & Carpus

During the initial stage of a perilunate dissociation (Mayfield Stage I), isolated disruption of the scapholunate interosseous ligament occurs. If left untreated, this specific ligamentous failure predominantly results in which radiographic deformity over time?

. Volar intercalated segment instability (VISI)
. Dorsal intercalated segment instability (DISI)
. Ulnar translocation of the carpus
. Proximal migration of the capitate
. Dorsal subluxation of the distal radioulnar joint

Correct Answer & Explanation

. Dorsal intercalated segment instability (DISI)

Explanation

Disruption of the scapholunate ligament allows the lunate to extend abnormally with the triquetrum, while the scaphoid flexes. This abnormal dorsal tilt of the lunate presents radiographically as a Dorsal Intercalated Segment Instability (DISI) deformity.

Question 612

Topic: Wrist & Carpus

A 28-year-old male sustains a transscaphoid perilunate fracture-dislocation. Despite prompt and anatomic open reduction and internal fixation, the patient remains at high risk for which of the following long-term complications due to the inherent vascular anatomy?

. Avascular necrosis of the capitate
. Avascular necrosis of the proximal pole of the scaphoid
. Hypothenar hammer syndrome
. Kienbock's disease isolated to the distal lunate pole
. Complex regional pain syndrome type II

Correct Answer & Explanation

. Avascular necrosis of the proximal pole of the scaphoid

Explanation

Transscaphoid perilunate dislocations carry a high risk of nonunion and avascular necrosis (AVN) of the proximal pole of the scaphoid. This is due to the retrograde intraosseous blood supply entering the scaphoid distally, which is disrupted by the fracture.

Question 613

Topic: 7. Hand and Wrist

A 25-year-old male undergoes open reduction and internal fixation for a transscaphoid perilunate fracture-dislocation. To restore carpal kinematics and prevent dorsal intercalated segment instability (DISI), repair of which specific structure is most critical alongside scaphoid fixation?

. Lunotriquetral ligament
. Volar radiocarpal ligament
. Scapholunate interosseous ligament
. Dorsal intercarpal ligament
. Triangular fibrocartilage complex

Correct Answer & Explanation

. Scapholunate interosseous ligament

Explanation

In transscaphoid perilunate dislocations, anatomic scaphoid fixation is paramount, but concurrent tears of the scapholunate interosseous ligament must also be repaired. Failure to address the SL ligament leads to progressive carpal collapse and DISI deformity.

Question 614

Topic: 7. Hand and Wrist
A 28-year-old male sustains a Bado type I Monteggia fracture-dislocation. Following closed reduction in the emergency department, he is unable to extend his thumb and fingers at the MCP joints, though wrist extension is preserved with radial deviation. Which nerve is most likely injured?
. Anterior interosseous nerve
. Posterior interosseous nerve
. Superficial radial nerve
. Ulnar nerve
. Median nerve

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

The posterior interosseous nerve (PIN) is frequently injured in Bado type I and type III Monteggia fractures. It presents with weakness in digit extension but preserved wrist extension, because the ECRL is innervated by the radial nerve proper proximal to the PIN branch.

Question 615

Topic: 7. Hand and Wrist
A 30-year-old male is diagnosed with a Mayfield stage IV carpal instability following a high-energy motorcycle crash. Which of the following radiographic findings characterizes this specific stage?
. Disruption of the scapholunate interval only
. Dorsal dislocation of the capitate relative to the lunate
. Volar dislocation of the lunate into the carpal tunnel
. Triquetral fracture with lunotriquetral dissociation
. Scaphoid waist fracture with proximal pole avascular necrosis

Correct Answer & Explanation

. Volar dislocation of the lunate into the carpal tunnel

Explanation

Mayfield stage IV represents the final stage of perilunate instability, where the dorsal radiocarpal ligament fails, allowing the lunate to dislocate volarly into the carpal tunnel. Stages I-III involve progressive destabilization around a normally seated lunate.

Question 616

Topic: 7. Hand and Wrist

A surgeon is performing an open reduction of a perilunate dislocation. What is the primary indication for utilizing a combined dorsal and volar approach rather than an isolated dorsal approach?

. Presence of a transscaphoid fracture
. Concomitant median nerve neuropathy failing to resolve with closed reduction
. To repair the dorsal intercarpal ligament
. To achieve anatomic reduction of the lunotriquetral interval
. Presence of a triquetral avulsion fracture

Correct Answer & Explanation

. Concomitant median nerve neuropathy failing to resolve with closed reduction

Explanation

A combined dorsal and volar approach is typically indicated when severe median nerve compression requires an open carpal tunnel release. An isolated dorsal approach is otherwise preferred for direct visualization and repair of the critical interosseous ligaments.

Question 617

Topic: 7. Hand and Wrist

During a perilunate dislocation, the carpus typically fails through the space of Poirier. Between which two structures is this space located?

. Scaphoid and lunate
. Lunate and capitate
. Capitate and hamate
. Radius and lunate
. Triquetrum and pisiform

Correct Answer & Explanation

. Lunate and capitate

Explanation

The space of Poirier is an area of relative weakness in the volar wrist capsule located between the volar radiocarpal ligaments and the volar intercarpal ligaments, spanning the lunocapitate joint. It is the site where the capitate typically dislocates dorsally in perilunate injuries.

Question 618

Topic: 7. Hand and Wrist
When evaluating a standard PA radiograph of the wrist for a suspected perilunate injury, disruption of Gilula's arcs is noted. Arc II represents the contour of which specific articular surfaces?
. Proximal articular surfaces of the scaphoid, lunate, and triquetrum
. Distal articular surfaces of the scaphoid, lunate, and triquetrum
. Proximal articular surfaces of the capitate and hamate
. Distal articular surfaces of the radius and ulna
. Articular surface between the trapezium and first metacarpal

Correct Answer & Explanation

. Proximal articular surfaces of the scaphoid, lunate, and triquetrum

Explanation

Gilula's arcs are three smooth radiographic lines used to assess carpal alignment. Arc I outlines the proximal convexities of the scaphoid, lunate, and triquetrum; Arc II outlines their distal concave surfaces; and Arc III outlines the proximal convexities of the capitate and hamate.

Question 619

Topic: 7. Hand and Wrist

Which of the following factors has been shown to be the most significant predictor of poor clinical outcomes and late post-traumatic arthritis following open reduction and internal fixation of a perilunate dislocation?

. Delay in surgery greater than 4 weeks
. Use of K-wires rather than screws for intercarpal fixation
. Patient age over 35 years
. Concomitant carpal tunnel syndrome at presentation
. Presence of a trans-triquetral fracture line

Correct Answer & Explanation

. Delay in surgery greater than 4 weeks

Explanation

Delays in the surgical treatment of perilunate dislocations, especially beyond 4 to 6 weeks, are strongly associated with poor outcomes, including persistent instability, stiffness, and severe post-traumatic arthritis.

Question 620

Topic: 7. Hand and Wrist

During the surgical management of a trans-scaphoid perilunate dislocation, the surgeon utilizes a combined dorsal and volar approach. What is the primary therapeutic advantage of incorporating the volar approach?

. Direct repair of the scapholunate interosseous ligament
. Anatomic reduction and fixation of the scaphoid waist
. Decompression of the carpal tunnel and repair of the rent in the Space of Poirier
. Restoration of Gilula's radiographic arcs
. Direct visualization and repair of the dorsal radiocarpal ligament

Correct Answer & Explanation

. Decompression of the carpal tunnel and repair of the rent in the Space of Poirier

Explanation

The volar approach in perilunate fracture-dislocations is essential for decompressing the median nerve in the carpal tunnel. It also allows direct access to repair the strong volar capsular ligaments, specifically addressing the capsular rent in the Space of Poirier to restore volar stability.

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