Menu

Wrist & Carpus MCQs

Practice Set 14 of 33

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

Question 261

Topic: Wrist & Carpus

A 35-year-old male undergoes ORIF for a distal-third radial shaft fracture with an associated distal radioulnar joint (DRUJ) dislocation (Galeazzi fracture). Intraoperatively, after rigid fixation of the radius, the DRUJ is found to be reducible but stable ONLY in full supination. What is the most appropriate next step in management?

. Immobilization in a long-arm cast or splint in supination
. Immobilization in a long-arm cast or splint in pronation
. Transfixion of the DRUJ with K-wires in neutral rotation
. Immediate open repair of the triangular fibrocartilage complex (TFCC)
. Darrach procedure

Correct Answer & Explanation

. Immobilization in a long-arm cast or splint in supination

Explanation

In a Galeazzi fracture, if the DRUJ is reducible and stable in supination after anatomic fixation of the radius, it is appropriate to immobilize the arm in supination for 4 to 6 weeks. K-wire transfixion or open repair is indicated if the joint remains unstable in all positions.

Question 262

Topic: Wrist & Carpus

A 48-year-old female was treated non-operatively in a cast for a nondisplaced distal radius fracture. Six weeks later, she reports a sudden inability to actively extend her thumb interphalangeal joint. What is the most appropriate and reliable surgical treatment?

. Primary end-to-end repair of the extensor pollicis longus (EPL)
. Extensor indicis proprius (EIP) to EPL tendon transfer
. Flexor carpi radialis (FCR) to EPL tendon transfer
. Palmaris longus interposition autograft
. Tenodesis of the EPL to the extensor digitorum communis (EDC)

Correct Answer & Explanation

. Extensor indicis proprius (EIP) to EPL tendon transfer

Explanation

Attritional rupture of the EPL tendon is a known complication of nondisplaced distal radius fractures due to ischemia or mechanical wear in Lister's tubercle. The standard and most reliable treatment is an EIP to EPL tendon transfer, as the native tendon ends are typically retracted and degenerated.

Question 263

Topic: Wrist & Carpus

A 28-year-old construction worker falls from a height and sustains a wrist injury. Radiographs show the lunate is displaced and rotated volar to the radius, while the capitate remains aligned with the radius. What is this injury pattern?

. Dorsal perilunate dislocation
. Volar lunate dislocation
. Scaphoid fracture dislocation
. Trans-scaphoid perilunate dislocation
. Barton fracture

Correct Answer & Explanation

. Volar lunate dislocation

Explanation

A volar lunate dislocation represents the final stage (Mayfield IV) of perilunate instability. The lunate is displaced volarly (the "spilled teacup" sign), while the capitate falls back into alignment with the radius.

Question 264

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 265

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 266

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 267

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 268

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 269

Topic: Wrist & Carpus

A 26-year-old motorcyclist falls onto an extended wrist. Lateral radiographs show a 'spilled teacup' sign with the lunate displaced volarly. The capitate is aligned with the radius. What is the correct diagnosis?

. Scaphoid fracture
. Perilunate dislocation
. Lunate dislocation
. Trans-scaphoid perilunate dislocation
. Volar Barton's fracture

Correct Answer & Explanation

. Lunate dislocation

Explanation

A volarly displaced and tipped lunate with the capitate maintaining its collinear alignment with the radius describes a lunate dislocation. In a perilunate dislocation, the lunate remains aligned with the radius while the rest of the carpus is dorsally dislocated.

Question 270

Topic: Wrist & Carpus

A 35-year-old man sustains a severe fall, leading to an Essex-Lopresti lesion. The central band of the interosseous membrane is torn. Which of the following best describes the normal anatomical orientation of the fibers of this central band?

. Proximal radius to distal ulna
. Proximal ulna to distal radius
. Transversely between the midshafts
. Proximal radius to proximal ulna
. Distal radius to distal ulna

Correct Answer & Explanation

. Proximal ulna to distal radius

Explanation

The central band of the interosseous membrane is the primary stabilizer against longitudinal proximal migration of the radius. Its fibers run obliquely from proximal on the radius to distal on the ulna.

Question 271

Topic: Wrist & Carpus

A 40-year-old male sustains an injury to the primary stabilizing structure of the distal radioulnar joint (DRUJ). Which structure is most crucial for DRUJ stability?

. Triangular fibrocartilage complex (TFCC)
. Extensor carpi ulnaris (ECU) subsheath
. Volar radiocarpal ligaments
. Interosseous membrane
. Pronator quadratus

Correct Answer & Explanation

. Triangular fibrocartilage complex (TFCC)

Explanation

The TFCC is the primary stabilizer of the DRUJ, specifically the deep radioulnar ligaments (ligamentum subcruentum) which attach to the fovea of the ulnar head.

Question 272

Topic: Wrist & Carpus

A patient presents with an attritional tendon rupture following a distal radius fracture. The ruptured tendon normally passes through the third dorsal extensor compartment. Which tendon is this?

. Extensor pollicis brevis
. Extensor carpi radialis longus
. Extensor pollicis longus
. Extensor indicis proprius
. Extensor digiti minimi

Correct Answer & Explanation

. Extensor pollicis longus

Explanation

The extensor pollicis longus (EPL) tendon is the sole occupant of the third dorsal extensor compartment and uses Lister's tubercle as a fulcrum.

Question 273

Topic: Wrist & Carpus

When stabilizing a dorsally comminuted distal radius fracture with a volar locking plate, what is the primary biomechanical advantage provided by the distal locking screws?

. They rely on dynamic compression between the plate and volar cortex
. They act as a fixed-angle construct to support subchondral bone and resist dorsal tilt
. They dynamically compress the dorsal fracture fragments
. They require bicortical purchase for maximal axial load support
. They increase friction at the bone-plate interface

Correct Answer & Explanation

. They act as a fixed-angle construct to support subchondral bone and resist dorsal tilt

Explanation

Volar locking plates utilize threaded screw heads that lock into the plate, creating a fixed-angle construct. This acts as a subchondral raft to support the joint surface and prevent late dorsal collapse without needing bicortical purchase.

Question 274

Topic: Wrist & Carpus

A 55-year-old woman was treated in a cast for a non-displaced distal radius fracture 6 weeks ago. She now presents with a sudden, painless inability to actively extend her thumb interphalangeal joint. What is the most appropriate surgical treatment?

. Primary end-to-end tendon repair
. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Flexor carpi radialis (FCR) to EPL tendon transfer
. Tendon graft using the palmaris longus
. Release of the first dorsal compartment

Correct Answer & Explanation

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

Explanation

EPL rupture is a known complication of non-displaced distal radius fractures due to ischemia or attrition at Lister's tubercle. Because the tendon ends are typically retracted and degenerated, primary repair is rarely possible, making EIP to EPL transfer the gold standard.

Question 275

Topic: Wrist & Carpus
A 45-year-old man presents with chronic wrist pain and is diagnosed with scaphoid nonunion advanced collapse (SNAC). Radiographs reveal arthritis sparing the radiolunate joint but involving the midcarpal joint. According to the SNAC staging system, Stage II disease is characterized by degenerative changes specifically involving which of the following joints?
. Radioscaphoid joint
. Scaphocapitate joint
. Capitolunate joint
. Lunotriquetral joint
. Distal radioulnar joint

Correct Answer & Explanation

. Scaphocapitate joint

Explanation

SNAC arthritis progresses predictably: Stage I involves the radial styloid and distal scaphoid. Stage II involves the scaphocapitate joint, while Stage III progresses to involve the capitolunate joint.

Question 276

Topic: Wrist & Carpus

A 62-year-old woman sustained a nondisplaced distal radius fracture treated nonoperatively in a cast. Two weeks after cast removal, she suddenly loses the ability to actively extend her thumb interphalangeal joint. What is the primary pathophysiology of this specific complication?

. Attritional rupture due to prominent volar hardware
. Ischemic necrosis of the tendon within the third extensor compartment
. Denervation of the extensor pollicis longus due to radial nerve traction
. Adhesions within the first dorsal compartment
. Unrecognized concomitant rupture at the time of the initial injury

Correct Answer & Explanation

. Ischemic necrosis of the tendon within the third extensor compartment

Explanation

Extensor pollicis longus (EPL) rupture is a known complication following nondisplaced distal radius fractures. Fracture hematoma and subsequent callus formation within the tight, unyielding third extensor compartment compromise the local microvascular supply, leading to ischemic necrosis and subsequent rupture of the EPL tendon.

Question 277

Topic: Wrist & Carpus

A 25-year-old man sustains a traumatic injury to his right forearm. Radiographs demonstrate a fracture of the distal third of the radial shaft with associated dorsal displacement of the distal ulna. Which of the following is the most appropriate definitive management?

. Closed reduction and long arm casting in supination
. Closed reduction and long arm casting in pronation
. Open reduction and internal fixation (ORIF) of the radius and pinning of the DRUJ if unstable
. ORIF of both the radius and the ulna
. External fixation of the radius with DRUJ pinning

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF) of the radius and pinning of the DRUJ if unstable

Explanation

A Galeazzi fracture (distal third radius fracture with DRUJ disruption) is highly unstable and requires ORIF of the radius in adults. The DRUJ should then be assessed and, if unstable, stabilized via pinning or immobilization in supination.

Question 278

Topic: Wrist & Carpus

A 55-year-old woman is treated in a cast for a minimally displaced distal radius fracture. Six weeks later, she notes a sudden inability to extend her thumb at the interphalangeal joint. What is the most likely etiology of this complication?

. FPL attrition rupture
. EPL ischemia and attrition
. Radial nerve neuropraxia
. Posterior interosseous nerve entrapment
. Abductor pollicis longus rupture

Correct Answer & Explanation

. EPL ischemia and attrition

Explanation

Extensor pollicis longus (EPL) ruptures typically occur after minimally displaced distal radius fractures. They result from local ischemia due to increased pressure within the intact third extensor compartment, followed by mechanical attrition.

Question 279

Topic: Wrist & Carpus

A 62-year-old woman undergoes volar locked plating for a distal radius fracture. Postoperatively, she develops flexor pollicis longus (FPL) tenosynovitis. What technical error is the most likely cause of this complication?

. Screws penetrating the dorsal cortex
. Plate placed proximal to the watershed line
. Plate placed distal to the watershed line
. Failure to repair the pronator quadratus
. Over-reduction of the volar tilt

Correct Answer & Explanation

. Plate placed distal to the watershed line

Explanation

Volar plates placed too distally (beyond the watershed line of the distal radius) can impinge on the flexor tendons, most commonly the FPL, leading to tenosynovitis or attrition rupture.

Question 280

Topic: Wrist & Carpus

A 65-year-old woman is evaluated 6 months after volar locked plating of a distal radius fracture. She now presents with a new-onset inability to actively flex the interphalangeal joint of her thumb. What is the most likely etiology?

. Extensor pollicis longus rupture
. Flexor pollicis longus rupture
. Anterior interosseous nerve palsy
. Trigger thumb
. Adhesions of the flexor digitorum profundus

Correct Answer & Explanation

. Flexor pollicis longus rupture

Explanation

Hardware placed prominent or volar to the watershed line of the distal radius can lead to attritional rupture of the flexor pollicis longus (FPL) tendon. The clinical presentation is a loss of active thumb interphalangeal joint flexion.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page