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7. Hand and Wrist MCQs

Practice Set 125 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 2481

Topic: Wrist & Carpus

A 45-year-old woman sustained a nondisplaced distal radius fracture treated in a cast. Six weeks later, she suddenly notices an inability to extend her thumb at the interphalangeal joint. She denies any new trauma. What is the most likely cause of this finding?

. Flexor pollicis longus rupture
. Anterior interosseous nerve palsy
. Extensor pollicis longus rupture at Lister's tubercle
. Posterior interosseous nerve palsy
. Extensor indicis proprius rupture

Correct Answer & Explanation

. Extensor pollicis longus rupture at Lister's tubercle

Explanation

Extensor pollicis longus (EPL) tendon rupture is a known complication following nondisplaced distal radius fractures due to ischemia or attrition at Lister's tubercle. It typically presents several weeks post-injury with an inability to actively extend the thumb interphalangeal joint.

Question 2482

Topic: 7. Hand and Wrist

A 22-year-old man falls on a hyperextended wrist. Radiographs reveal a displaced fracture of the proximal pole of the scaphoid. What is the primary arterial supply to the proximal pole of the scaphoid, which places this injury at high risk for avascular necrosis?

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

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The dorsal carpal branch of the radial artery provides the predominant blood supply to the scaphoid, entering distally and flowing retrogradely to the proximal pole. Fractures at the proximal pole disrupt this retrograde flow, heavily increasing the risk of avascular necrosis.

Question 2483

Topic: Wrist & Carpus

A 28-year-old man sustains a fracture of the middle third of the radius with associated distal radioulnar joint (DRUJ) dislocation. Following rigid open reduction and internal fixation of the radius, the DRUJ easily reduces but subluxates in pronation while remaining completely stable in supination. What is the next best step in management?

. Immobilize the forearm in supination for 4 weeks
. Immobilize the forearm in pronation for 4 weeks
. Pin the DRUJ in neutral rotation
. Perform an open repair of the triangular fibrocartilage complex (TFCC)
. Resect the distal ulna (Darrach procedure)

Correct Answer & Explanation

. Immobilize the forearm in supination for 4 weeks

Explanation

If the DRUJ is stable in supination following anatomic fixation of a Galeazzi fracture, the treatment of choice is immobilization in supination for 4-6 weeks. Operative intervention (pinning or TFCC repair) is reserved for cases that are unstable in all positions of rotation.

Question 2484

Topic: 7. Hand and Wrist

A 55-year-old woman is treated with a volar locking plate for a displaced volar Barton's fracture. Postoperatively, she develops severe paresthesias and burning pain in her thumb, index, and middle fingers that fail to improve after two weeks. Which of the following is the most appropriate next step?

. Observation and reassurance for an additional 4 weeks
. Prescribe a 10-day course of oral corticosteroids
. Median nerve decompression and carpal tunnel release
. Immediate hardware removal and casting
. Electromyography and nerve conduction studies

Correct Answer & Explanation

. Median nerve decompression and carpal tunnel release

Explanation

Post-traumatic carpal tunnel syndrome can occur after distal radius fracture or its fixation. Severe, unrelenting, or progressive symptoms of median neuropathy following ORIF should prompt surgical median nerve decompression to prevent permanent nerve injury.

Question 2485

Topic: 7. Hand and Wrist
A 28-year-old man falls backward on an extended, ulnarly deviated wrist. Radiographs reveal a volar lunate dislocation. According to Mayfield's progressive stages of perilunate instability, what is the exact sequence of ligamentous failure leading to this end-stage injury?
. Scapholunate, lunotriquetral, midcarpal, radiolunate
. Scapholunate, capitohamate, lunotriquetral, dorsal radiocarpal
. Scapholunate, capitolunate, lunotriquetral, dorsal radiocarpal
. Lunotriquetral, capitolunate, scapholunate, dorsal radiocarpal
. Lunotriquetral, midcarpal, scapholunate, volar radiocarpal

Correct Answer & Explanation

. Scapholunate, capitolunate, lunotriquetral, dorsal radiocarpal

Explanation

Mayfield described a four-stage progression of perilunate instability starting radially and progressing ulnarly. Stage I disrupts the scapholunate joint, Stage II the capitolunate joint, Stage III the lunotriquetral joint, and Stage IV involves dorsal radiocarpal disruption allowing the lunate to dislocate volarly.

Question 2486

Topic: 7. Hand and Wrist

A 21-year-old male presents with radial-sided wrist pain after falling on an outstretched hand. Radiographs show a displaced fracture of the proximal pole of the scaphoid. Which of the following blood supplies is most at risk, and what is the optimal surgical approach?

. Dorsal carpal branch of the radial artery; volar approach
. Dorsal carpal branch of the radial artery; dorsal approach
. Superficial palmar arch; volar approach
. Superficial palmar arch; dorsal approach
. Ulnar artery; dorsal approach

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery; dorsal approach

Explanation

The proximal pole of the scaphoid relies on retrograde blood flow from the dorsal carpal branch of the radial artery. A dorsal surgical approach is preferred for proximal pole fractures to achieve direct access without further jeopardizing this blood supply.

Question 2487

Topic: Wrist & Carpus

A 28-year-old motorcyclist is involved in a high-speed collision. Lateral wrist radiographs show the lunate is displaced and rotated volar to the radius, while the capitate remains aligned with the longitudinal axis of the radius. What is the diagnosis?

. Dorsal perilunate dislocation
. Volar perilunate dislocation
. Lunate dislocation
. Scaphoid fracture
. Barton's fracture

Correct Answer & Explanation

. Lunate dislocation

Explanation

This classic 'spilled teacup' sign on the lateral radiograph, where the lunate is volarly displaced while the capitate remains colinear with the radius, defines a lunate dislocation. In a perilunate dislocation, the lunate remains seated in the radial fossa while the capitate is dislocated.

Question 2488

Topic: 7. Hand and Wrist

A 45-year-old man undergoes a modified two-incision repair for a distal biceps tendon rupture. Postoperatively, he presents with the inability to actively extend his fingers and thumb at the metacarpophalangeal joints. Wrist extension is preserved but deviates radially. Which nerve is most likely injured?

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

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

The posterior interosseous nerve (PIN) is highly vulnerable during the lateral exposure of a two-incision distal biceps repair. PIN palsy results in loss of digit extension and radial deviation during wrist extension due to extensor carpi ulnaris weakness.

Question 2489

Topic: Wrist & Carpus

Six weeks after undergoing nonoperative management of a nondisplaced distal radius fracture, a 60-year-old woman suddenly loses the ability to extend her thumb interphalangeal joint. What is the most appropriate surgical management?

. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Primary end-to-end repair of the EPL tendon
. Extensor carpi radialis longus (ECRL) to EPL tendon transfer
. Release of the first dorsal compartment
. Observation and dynamic splinting

Correct Answer & Explanation

. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer

Explanation

Delayed EPL rupture after a distal radius fracture is secondary to attrition or ischemia in the third dorsal compartment. Primary repair is typically impossible due to tendon retraction and degeneration, making EIP-to-EPL transfer the gold standard.

Question 2490

Topic: 7. Hand and Wrist

A 30-year-old male presents after a motorcycle crash with a swollen, painful wrist and numbness in his thumb, index, and long fingers. The lateral radiograph shows the lunate displaced palmar to the radius, while the capitate remains aligned with the radius. What is the diagnosis?

. Dorsal perilunate dislocation.
. Volar perilunate dislocation.
. Lunate dislocation.
. Scapholunate dissociation.
. Midcarpal dislocation.

Correct Answer & Explanation

. Lunate dislocation.

Explanation

In a lunate dislocation, the lunate is displaced and tilted palmarly (creating a 'spilled teacup' sign on the lateral radiograph), while the capitate remains aligned with the radius. Median nerve symptoms are common due to acute carpal tunnel compression.

Question 2491

Topic: 7. Hand and Wrist

A 65-year-old woman is seen 6 months after undergoing volar locked plating for a distal radius fracture. She complains of a sudden inability to flex the interphalangeal joint of her thumb. What is the most likely etiology?

. Anterior interosseous nerve injury
. Extensor pollicis longus tendon rupture
. Flexor pollicis longus tendon rupture
. Flexor digitorum profundus tendon rupture
. Median nerve compression

Correct Answer & Explanation

. Flexor pollicis longus tendon rupture

Explanation

Flexor pollicis longus (FPL) tendon rupture is a well-documented complication of volar plating of the distal radius. It typically occurs due to attritional wear when the plate is positioned distal to the watershed line (Soong Grade 2).

Question 2492

Topic: 7. Hand and Wrist

A 28-year-old male presents with a volar lunate dislocation following a fall on an extended wrist. According to the Mayfield sequence of perilunate instability, what is the first intercarpal ligament to rupture?

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

Correct Answer & Explanation

. Scapholunate interosseous ligament

Explanation

The Mayfield sequence describes the progressive disruption of perilunate ligaments from radial to ulnar. Stage I begins with the rupture of the scapholunate interosseous ligament.

Question 2493

Topic: 7. Hand and Wrist

A 24-year-old man sustains a proximal pole scaphoid fracture. The high risk of avascular necrosis (AVN) in this region is primarily due to which of the following anatomic characteristics?

. Absence of an intra-articular capsular reflection
. Retrograde intraosseous blood supply via the dorsal carpal branch of the radial artery
. Rich network of volar perforators that are easily disrupted
. Lack of hyaline cartilage protecting the proximal pole
. Insertion of the radioscaphocapitate ligament

Correct Answer & Explanation

. Retrograde intraosseous blood supply via the dorsal carpal branch of the radial artery

Explanation

The proximal pole of the scaphoid is entirely covered by articular cartilage and relies on a retrograde blood supply from vessels entering the dorsal ridge distally. Fractures of the proximal pole frequently disrupt this blood supply, causing AVN.

Question 2494

Topic: 7. Hand and Wrist
A 55-year-old man presents with chronic wrist pain. Radiographs reveal Scapholunate Advanced Collapse (SLAC) Stage III, characterized by arthritis in the capitolunate joint. Which of the following articulations is typically spared in this condition?
. Radioscaphoid
. Capitolunate
. Radiolunate
. Scaphocapitale
. Trapeziometacarpal

Correct Answer & Explanation

. Radiolunate

Explanation

In SLAC wrist, the radiolunate joint is characteristically spared due to the concentric shape of the lunate fossa and its strong ligamentous supports. This sparing allows for salvage procedures like a four-corner fusion.

Question 2495

Topic: 7. Hand and Wrist

During a carpal tunnel release, care must be taken to avoid injury to the recurrent motor branch of the median nerve. In the most common anatomical variation (extraligamentous), this branch originates:

. Proximal to the transverse carpal ligament
. Beneath the transverse carpal ligament and pierces it
. Distal to the transverse carpal ligament and courses retrogradely
. From the ulnar nerve via a Martin-Gruber anastomosis
. From the palmar cutaneous branch

Correct Answer & Explanation

. Distal to the transverse carpal ligament and courses retrogradely

Explanation

The extraligamentous type is the most common anatomical variant (approximately 50-80%), where the recurrent motor branch arises distal to the transverse carpal ligament and loops back to innervate the thenar muscles.

Question 2496

Topic: Nerve & Tendon

A patient undergoes in situ decompression of the ulnar nerve for cubital tunnel syndrome. During the approach, the roof of the cubital tunnel is incised. What structure primarily forms the roof of this tunnel?

. Osborne's ligament (FCU aponeurosis)
. Medial collateral ligament
. Medial epicondyle
. Arcade of Struthers
. Brachialis fascia

Correct Answer & Explanation

. Osborne's ligament (FCU aponeurosis)

Explanation

The roof of the cubital tunnel is primarily formed by Osborne's ligament, which is the aponeurotic band connecting the humeral and ulnar heads of the flexor carpi ulnaris (FCU).

Question 2497

Topic: Wrist & Carpus

A 25-year-old gymnast complains of ulnar-sided wrist pain after a fall. Examination reveals a positive fovea sign and pain with ulnar deviation. MRI confirms a Palmer Type 1B tear of the Triangular Fibrocartilage Complex (TFCC). What is the appropriate surgical management if conservative treatment fails?

. Arthroscopic debridement of the central disc
. Open ulnar shortening osteotomy
. Arthroscopic repair of the TFCC to the fovea
. Darrach procedure
. Wafer procedure

Correct Answer & Explanation

. Arthroscopic repair of the TFCC to the fovea

Explanation

A Palmer Type 1B tear is an avulsion of the TFCC from its ulnar insertion (fovea/ulnar styloid). Direct surgical repair (arthroscopic or open) to the fovea is the standard of care to restore distal radioulnar joint (DRUJ) stability.

Question 2498

Topic: 7. Hand and Wrist
A 45-year-old manual laborer presents with chronic wrist pain. Radiographs demonstrate a scaphoid nonunion with radioscaphoid and capitolunate arthritis, but the radiolunate joint is completely preserved. What is the most appropriate surgical intervention?
. Proximal row carpectomy
. Scaphoid excision and four-corner fusion
. Total wrist arthrodesis
. Radial styloidectomy
. Vascularized bone grafting of the scaphoid

Correct Answer & Explanation

. Scaphoid excision and four-corner fusion

Explanation

This presentation describes SNAC stage III with capitolunate arthritis, which makes a proximal row carpectomy contraindicated due to capitate wear. Scaphoid excision and four-corner fusion preserves some wrist motion while relying on the spared radiolunate joint.

Question 2499

Topic: 7. Hand and Wrist

A 55-year-old woman undergoes volar locked plating for a comminuted distal radius fracture. Six months later, she presents unable to actively flex the interphalangeal joint of her thumb. What technical error during the initial surgery most likely caused this complication?

. Screw penetration into the radiocarpal joint
. Plate placement distal to the watershed line
. Over-penetration of dorsal screws through the distal cortex
. Malreduction of the sigmoid notch
. Iatrogenic injury to the recurrent motor branch of the median nerve

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a known complication of volar plating of the distal radius. It classically occurs when the plate is placed distal to the watershed line, causing mechanical attrition of the tendon against the prominent hardware.

Question 2500

Topic: Nerve & Tendon

A 42-year-old bodybuilder feels a 'pop' in his anterior elbow followed by weakness in supination. He undergoes a classic two-incision distal biceps tendon repair. Which nerve is at greatest risk of injury during the posterolateral dissection of this approach?

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

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

The posterior interosseous nerve (PIN) is at greatest risk during the two-incision approach. This risk is minimized by keeping the forearm in full pronation during the posterolateral muscle splitting dissection.

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