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7. Hand and Wrist MCQs

Practice Set 123 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 2441

Topic: 7. Hand and Wrist

A 62-year-old woman presents with the inability to flex her thumb interphalangeal joint 9 months after volar plate fixation of a distal radius fracture.

What is the most likely cause of her current symptoms?

. Anterior interosseous nerve palsy
. Flexor pollicis longus attrition rupture
. Extensor pollicis longus rupture
. Median nerve compression
. Trigger thumb

Correct Answer & Explanation

. Flexor pollicis longus attrition rupture

Explanation

Prominent volar hardware at or distal to the watershed line can cause attrition and subsequent rupture of the flexor pollicis longus (FPL) tendon. The patient's specific loss of active thumb interphalangeal joint flexion is a classic presentation of this complication.

Question 2442

Topic: Nerve & Tendon

A 35-year-old man undergoes surgical repair of a distal biceps tendon rupture via a single-incision anterior approach. Postoperatively, he notes numbness over the lateral aspect of his forearm. Which nerve was most likely injured during the procedure?

. Superficial radial nerve
. Lateral antebrachial cutaneous nerve
. Posterior interosseous nerve
. Median nerve
. Ulnar nerve

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve

Explanation

The lateral antebrachial cutaneous (LABC) nerve, a terminal branch of the musculocutaneous nerve, is highly susceptible to traction or transection injury during the single-incision anterior approach. Injury results in sensory deficits along the lateral forearm.

Question 2443

Topic: 7. Hand and Wrist

A 45-year-old woman falls on an outstretched hand and sustains a comminuted radial head fracture. Three weeks after isolated radial head excision, she develops progressive, severe wrist pain and prominence of the ulnar head. What is the underlying pathology?

. Missed scaphoid fracture
. Undiagnosed TFCC tear without interosseous membrane injury
. Essex-Lopresti lesion with interosseous membrane disruption
. Ulnar impaction syndrome due to prior Madelung deformity
. Post-traumatic radioulnar synostosis

Correct Answer & Explanation

. Essex-Lopresti lesion with interosseous membrane disruption

Explanation

An Essex-Lopresti injury involves a radial head fracture accompanied by rupture of the interosseous membrane and disruption of the distal radioulnar joint (DRUJ). Excision of the radial head in this unrecognized setting leads to proximal migration of the radius, relative ulnar lengthening, and severe ulnocarpal impingement.

Question 2444

Topic: 7. Hand and Wrist

A 30-year-old construction worker falls from a height. Radiographs reveal a dorsal perilunate dislocation. The patient urgently complains of severe numbness and tingling in the thumb, index, and middle fingers. Which nerve is most likely affected by this injury pattern?

. Ulnar nerve
. Superficial radial nerve
. Posterior interosseous nerve
. Anterior interosseous nerve
. Median nerve

Correct Answer & Explanation

. Median nerve

Explanation

Acute carpal tunnel syndrome caused by compression of the median nerve is a frequent neurologic complication of perilunate and lunate dislocations. Prompt closed reduction and potential surgical carpal tunnel release are necessary to relieve the compressive neuropathy.

Question 2445

Topic: Wrist & Carpus

A 65-year-old woman undergoes volar plate fixation for a displaced distal radius fracture. Six months later, she presents with an inability to actively flex her thumb interphalangeal joint. What surgical error is most likely responsible for this complication?

. Prominent dorsal screws
. Plate placed proximal to the watershed line
. Plate placed distal to the watershed line
. Over-reduction of volar tilt
. Radial translation of the plate

Correct Answer & Explanation

. Plate placed distal to the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a known complication of volar plating when the plate is placed too distally (prominent beyond the watershed line), causing mechanical attrition of the tendon.

Question 2446

Topic: 7. Hand and Wrist
In Scapholunate Advanced Collapse (SLAC) of the wrist, which articular surface is typically spared from degenerative changes even in advanced stages (Stage III)?
. Radioscaphoid joint
. Capitolunate joint
. Radiolunate joint
. Scaphocapitate joint
. Scaphotrapezial joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

The radiolunate articulation is classically spared in SLAC wrist due to the spherical congruency of the lunate fossa and the lunate, which maintains contact despite the rotatory subluxation of the scaphoid.

Question 2447

Topic: 7. Hand and Wrist

A 35-year-old male construction worker presents with chronic wrist pain and a known history of a scaphoid nonunion. Radiographs demonstrate advanced radiocarpal arthritis and capitolunate arthritis, but the radiolunate joint is completely spared. What is the most appropriate motion-preserving surgical procedure?

. Proximal row carpectomy
. Total wrist fusion
. Four-corner fusion with scaphoid excision
. Radial styloidectomy
. Scapholunate ligament repair

Correct Answer & Explanation

. Four-corner fusion with scaphoid excision

Explanation

This patient has Scaphoid Nonunion Advanced Collapse (SNAC) with capitolunate arthritis. Proximal row carpectomy is contraindicated when the capitate articular surface is degenerate, making a four-corner fusion the most appropriate motion-preserving option.

Question 2448

Topic: Wrist & Carpus

A 55-year-old woman underwent volar locked plating of a distal radius fracture 6 months ago. She now presents with a sudden inability to actively flex the interphalangeal joint of her thumb. What is the most likely cause of this complication?

. Extensor pollicis longus rupture
. Flexor carpi radialis rupture
. Flexor pollicis longus rupture
. Flexor digitorum profundus rupture
. Anterior interosseous nerve palsy

Correct Answer & Explanation

. Flexor pollicis longus rupture

Explanation

Flexor pollicis longus (FPL) tendon rupture is a well-documented complication of volar plating for distal radius fractures. It typically occurs due to attritional wear from plate placement distal to the watershed line.

Question 2449

Topic: Wrist & Carpus

A 55-year-old woman undergoes volar locked plating for a distal radius fracture. Six months postoperatively, she is unable to actively flex the interphalangeal joint of her thumb. Which of the following technical errors most likely contributed to this complication?

. Placement of screws dorsal to the Lister tubercle
. Plate placement distal to the watershed line
. Inadequate reduction of the volar lunate facet
. Screws penetrating the distal radioulnar joint (DRUJ)
. Failure to repair the pronator quadratus

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a known and significant complication of volar locked plating for distal radius fractures. It is most commonly caused by hardware prominence due to plate placement distal to the watershed line, leading to tendon attrition.

Question 2450

Topic: 7. Hand and Wrist

A 32-year-old man presents with chronic wrist pain. Radiographs reveal a scaphoid nonunion with radioscaphoid arthritis, but preservation of the midcarpal and radiolunate joints. Which of the following is the most appropriate surgical treatment?

. Proximal row carpectomy (PRC)
. Four-corner arthrodesis
. Total wrist arthrodesis
. Scaphoid excision and four-corner arthrodesis
. Radial styloidectomy and scaphoid bone grafting

Correct Answer & Explanation

. Scaphoid excision and four-corner arthrodesis

Explanation

The patient has Stage II scaphoid nonunion advanced collapse (SNAC). Because the radiolunate articulation is preserved, scaphoid excision and four-corner arthrodesis (or PRC) is the treatment of choice to relieve pain while maintaining some wrist motion.

Question 2451

Topic: 7. Hand and Wrist

A 22-year-old male sustains a minimally displaced fracture of the scaphoid waist. Which of the following best describes the primary blood supply to the proximal pole of the scaphoid?

. Volar carpal branch of the radial artery
. Dorsal carpal branch of the radial artery
. Ulnar artery
. Anterior interosseous artery
. Deep palmar arch

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The primary blood supply to the scaphoid is from the dorsal carpal branch of the radial artery, which enters the distal 80% of the bone and provides retrograde blood flow to the proximal pole. This tenuous retrograde supply increases the risk of avascular necrosis in proximal pole fractures.

Question 2452

Topic: Wrist & Carpus

Which of the following represents an acceptable radiographic parameter for the nonoperative management of a distal radius fracture in an active adult?

. Radial shortening of 8 mm
. Articular step-off of 3 mm
. Dorsal tilt less than 10 degrees past neutral
. Radial inclination less than 10 degrees
. Volar tilt greater than 25 degrees

Correct Answer & Explanation

. Radial shortening of 8 mm

Explanation

Acceptable radiographic parameters for nonoperative management of a distal radius fracture typically include radial shortening < 5 mm, dorsal tilt < 10 degrees past neutral (or < 15 degrees), and articular step-off < 2 mm.

Question 2453

Topic: 7. Hand and Wrist

In a purely ligamentous lesser arc perilunate dislocation of the wrist, which carpal bone classically remains anatomically aligned with the distal radius on a true lateral radiograph?

. Scaphoid
. Lunate
. Capitate
. Triquetrum
. Trapezium

Correct Answer & Explanation

. Lunate

Explanation

In a perilunate dislocation, the lunate remains contained within the lunate fossa of the distal radius, while the capitate and the rest of the carpus dislocate dorsally. In a lunate dislocation, the lunate is displaced anteriorly ('spilled teacup').

Question 2454

Topic: 7. Hand and Wrist
In the natural history of a scaphoid nonunion advanced collapse (SNAC) wrist, where are the degenerative changes primarily located during Stage II?
. Radioscaphoid joint
. Scaphocapitate joint
. Capitolunate joint
. Radioulnar joint
. Lunotriquetral joint

Correct Answer & Explanation

. Capitolunate joint

Explanation

In a SNAC wrist, Stage I involves arthritis between the radial styloid and the distal scaphoid fragment. Stage II progresses to involve the scaphocapitate joint. Stage III involves the capitolunate joint.

Question 2455

Topic: 7. Hand and Wrist

A 22-year-old athlete sustains a proximal pole scaphoid fracture. Which of the following vascular structures provides the primary retrograde blood supply to the proximal pole, explaining the high risk of avascular necrosis (AVN) in this fracture pattern?

. Volar carpal branch of the radial artery
. Dorsal carpal branch of the radial artery
. Superficial palmar arch
. Anterior interosseous artery
. Recurrent branch of the ulnar artery

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The dorsal carpal branch of the radial artery enters the scaphoid at the distal pole and provides retrograde blood supply to the proximal pole. Fractures at the proximal pole disrupt this supply, resulting in a high rate of AVN.

Question 2456

Topic: Wrist & Carpus

A 28-year-old male sustains a Galeazzi fracture-dislocation. After plate fixation of the radial shaft, the distal radioulnar joint (DRUJ) remains unstable. Which muscle provides the primary deforming force causing volar and ulnar translation of the distal radius fragment?

. Pronator teres
. Pronator quadratus
. Brachioradialis
. Flexor pollicis longus
. Extensor carpi radialis longus

Correct Answer & Explanation

. Pronator quadratus

Explanation

In a Galeazzi fracture, the brachioradialis pulls the proximal fragment proximally, while the pronator quadratus pulls the distal fragment in a volar and ulnar direction, leading to the characteristic deformity.

Question 2457

Topic: 7. Hand and Wrist

A patient falls from a height and sustains a Mayfield Stage IV perilunate dislocation. Review the provided reference image.

What is the characteristic position of the lunate in a Stage IV injury?

. Dislocated dorsally relative to the radius
. Dislocated volarly into the carpal tunnel
. Rotated 90 degrees sagitally but contained in the radiocarpal joint
. Migrated proximally between the radius and ulna
. Articulating normally with the capitate but separated from the scaphoid

Correct Answer & Explanation

. Dislocated volarly into the carpal tunnel

Explanation

In Mayfield Stage IV (lunate dislocation), the dorsal radiocarpal ligament ruptures, and the lunate is extruded volarly into the carpal tunnel. This commonly causes acute median nerve compression.

Question 2458

Topic: Wrist & Carpus

A 65-year-old woman undergoes volar plate fixation for a distal radius fracture. Six months postoperatively, she presents with an inability to actively flex the interphalangeal joint of her thumb. Placement of the plate distal to which of the following anatomical landmarks is the primary risk factor for this complication?

. Lister's tubercle
. Watershed line
. Sigmoid notch
. Brachioradialis insertion
. Pronator quadratus insertion

Correct Answer & Explanation

. Watershed line

Explanation

The watershed line is the bony ridge on the volar distal radius. Plate placement distal to this line significantly increases the risk of flexor pollicis longus (FPL) tendon attrition and subsequent rupture.

Question 2459

Topic: 7. Hand and Wrist

A 22-year-old male sustains a proximal pole scaphoid fracture. Which of the following arterial branches is responsible for the retrograde blood supply to the proximal pole, making it highly susceptible to avascular necrosis?

. Deep palmar arch
. Superficial palmar arch
. Volar carpal branch of the radial artery
. Dorsal carpal branch of the radial artery
. Anterior interosseous artery

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The scaphoid receives its primary blood supply from the dorsal carpal branch of the radial artery, which enters at the distal pole and waist, providing retrograde flow to the proximal pole.

Question 2460

Topic: 7. Hand and Wrist

A 60-year-old woman undergoes volar locked plating of a distal radius fracture. Postoperatively, she is unable to actively flex the interphalangeal joint of her thumb. This complication is most commonly associated with which of the following?

. Plate placement proximal to the watershed line
. Plate placement distal to the watershed line
. Penetration of screws into the dorsal cortex
. Use of a prominent dorsal spanning plate
. Unrecognized intra-operative median nerve injury

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a well-known complication of volar locked plating. It most frequently occurs when the plate is placed distal to the watershed line, causing attritional wear of the tendon.

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