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Wrist & Carpus MCQs

Practice Set 15 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 281

Topic: Wrist & Carpus

A 32-year-old man sustains a Galeazzi fracture. After achieving anatomic open reduction and internal fixation of the radius, intraoperative assessment reveals the distal radioulnar joint (DRUJ) remains unstable in supination. What is the most appropriate next step in management?

. Transfix the DRUJ with K-wires in supination
. Transfix the DRUJ with K-wires in neutral rotation
. Proceed to immediate open reduction of the DRUJ
. Perform a distal ulnar resection (Darrach procedure)
. Immobilize the patient in a cast in full pronation

Correct Answer & Explanation

. Transfix the DRUJ with K-wires in supination

Explanation

In a Galeazzi fracture-dislocation, if the DRUJ remains unstable despite anatomic radius fixation, the joint should be transfixed with K-wires in the position of maximum stability, which is typically full supination.

Question 282

Topic: Wrist & Carpus

During open reduction and internal fixation of a Galeazzi fracture-dislocation in a 30-year-old man, the distal radius is anatomically plated. Intraoperative evaluation reveals that the distal radioulnar joint (DRUJ) remains grossly unstable in supination. What is the most appropriate next step in management?

. Repair the triangular fibrocartilage complex (TFCC) and/or pin the DRUJ
. Resect the distal ulna (Darrach procedure)
. Perform a Sauve-Kapandji procedure
. Immobilize the wrist in full pronation for 6 weeks
. Accept the instability as it will self-stabilize with soft tissue healing

Correct Answer & Explanation

. Repair the triangular fibrocartilage complex (TFCC) and/or pin the DRUJ

Explanation

In a Galeazzi fracture, if the DRUJ remains unstable after anatomic stabilization of the radius, operative intervention of the DRUJ is required. This consists of repairing the TFCC or pinning the DRUJ in the position of maximum stability (usually supination).

Question 283

Topic: Wrist & Carpus

A 45-year-old woman sustains a nondisplaced distal radius fracture treated in a short arm cast. Six weeks later, after cast removal, she suddenly loses the ability to actively extend the interphalangeal joint of her thumb. What is the most likely diagnosis?

. Posterior interosseous nerve palsy
. Extensor pollicis longus tendon rupture
. Flexor pollicis longus tendon rupture
. Anterior interosseous nerve palsy
. Stenosing tenosynovitis of the first dorsal compartment

Correct Answer & Explanation

. Extensor pollicis longus tendon rupture

Explanation

Extensor pollicis longus (EPL) ruptures frequently occur following nondisplaced distal radius fractures due to mechanical attrition or local ischemia at Lister's tubercle. Treatment typically involves an extensor indicis proprius (EIP) to EPL tendon transfer.

Question 284

Topic: Wrist & Carpus

Which of the following factors most significantly increases the risk of avascular necrosis and nonunion following a scaphoid fracture?

. Distal pole location
. Volar comminution
. Delay in casting of 3 days
. Proximal pole location
. Associated distal radius fracture

Correct Answer & Explanation

. Proximal pole location

Explanation

The blood supply to the scaphoid enters at the dorsal ridge distally and flows in a retrograde fashion. Consequently, proximal pole fractures are at the highest risk for ischemia, avascular necrosis, and nonunion.

Question 285

Topic: Wrist & Carpus

A 28-year-old active manual laborer complains of ulnar-sided wrist pain 6 months after a nonoperatively treated distal radius fracture. Radiographs show a shortened, dorsally angulated distal radius with DRUJ incongruity. What is the most appropriate definitive surgical intervention?

. Darrach procedure (ulnar head resection)
. Sauve-Kapandji procedure
. Ulnar shortening osteotomy
. Distal radius corrective opening-wedge osteotomy
. Total wrist arthrodesis

Correct Answer & Explanation

. Distal radius corrective opening-wedge osteotomy

Explanation

In a young, active patient with an extra-articular distal radius malunion causing secondary DRUJ dysfunction, a corrective osteotomy of the radius restores native anatomy, mechanics, and DRUJ congruity. Procedures like the Darrach are reserved for low-demand or elderly patients.

Question 286

Topic: Wrist & Carpus

A 28-year-old gymnast presents with chronic ulnar-sided wrist pain. Examination reveals a positive foveal sign. MRI arthrogram demonstrates a peripheral tear of the triangular fibrocartilage complex (TFCC) with an avulsion from the fovea of the ulna. This corresponds to which Palmer classification, and what is the preferred treatment?

. Palmer 1A; Debridement
. Palmer 1B; Open or arthroscopic repair
. Palmer 1C; Ulnar shortening osteotomy
. Palmer 1D; Proximal row carpectomy
. Palmer 2C; Darrach procedure

Correct Answer & Explanation

. Palmer 1B; Open or arthroscopic repair

Explanation

A peripheral tear of the TFCC involving the foveal attachment is classified as Palmer 1B. Because the peripheral TFCC has excellent blood supply, these tears are highly amenable to open or arthroscopic surgical repair.

Question 287

Topic: Wrist & Carpus
A 45-year-old male presents with chronic wrist pain and a history of a scaphoid fracture 15 years ago. Radiographs demonstrate advanced radioscaphoid arthritis and scaphocapitate arthritis, but the radiolunate joint is completely spared (SNAC Stage III). What is the most appropriate definitive surgical intervention?
. Proximal row carpectomy
. Total wrist arthrodesis
. Four-corner arthrodesis with scaphoid excision
. Radiolunate arthrodesis
. Darrach procedure

Correct Answer & Explanation

. Four-corner arthrodesis with scaphoid excision

Explanation

In Scaphoid Nonunion Advanced Collapse (SNAC) Stage III, there is arthritic involvement of both the radioscaphoid and midcarpal (scaphocapitate) joints. Proximal row carpectomy is contraindicated when the capitate is arthritic, making four-corner arthrodesis the procedure of choice.

Question 288

Topic: Wrist & Carpus

A 24-year-old gymnast complains of ulnar-sided wrist pain and clicking. Examination reveals severe distal radioulnar joint (DRUJ) instability in both supination and pronation. MRI confirms a foveal avulsion of the triangular fibrocartilage complex (TFCC). What is the primary biomechanical function of the foveal attachment of the TFCC?

. Stabilizes the ulnocarpal joint against axial load
. Prevents volar translation of the carpus
. Provides the primary restraint to DRUJ translation
. Acts as an articular cushion for the lunate
. Prevents dorsal intercalated segment instability (DISI)

Correct Answer & Explanation

. Provides the primary restraint to DRUJ translation

Explanation

The deep foveal attachment of the TFCC inserts into the base of the ulnar styloid and constitutes the primary stabilizing restraint to distal radioulnar joint (DRUJ) translation. Tears at this location (Type 1B) reliably result in DRUJ instability and often require open or arthroscopic repair.

Question 289

Topic: Wrist & Carpus

A 55-year-old woman sustains a nondisplaced distal radius fracture treated in a short arm cast. Six weeks later, the cast is removed, and she is unable to actively extend her thumb interphalangeal joint. Tenodesis effect of the thumb is absent. What is the most likely etiology?

. Posterior interosseous nerve palsy
. Extensor pollicis longus rupture
. Flexor pollicis longus rupture
. Extensor indicis proprius rupture
. Anterior interosseous nerve palsy

Correct Answer & Explanation

. Posterior interosseous nerve palsy

Explanation

Extensor pollicis longus (EPL) tendon rupture is a well-known complication of nondisplaced distal radius fractures. It occurs due to a combination of mechanical attrition at Lister's tubercle and ischemia in a watershed vascular zone.

Question 290

Topic: Wrist & Carpus

A 33-year-old construction worker sustains a fracture of the distal third of the radial shaft with associated disruption of the distal radioulnar joint (DRUJ). After rigid open reduction and internal fixation of the radius, the DRUJ remains highly unstable. What is the most appropriate next step in management?

. Pinning the DRUJ in maximum supination
. Pinning the DRUJ in maximum pronation
. Casting the arm in neutral rotation without pinning
. Resection of the distal ulna (Darrach procedure)
. Immediate ulnar shortening osteotomy

Correct Answer & Explanation

. Pinning the DRUJ in maximum supination

Explanation

In a Galeazzi fracture, if the DRUJ remains unstable after rigid anatomical fixation of the radius, it should be pinned in the position of maximum stability. For most DRUJ instabilities, this position is full supination.

Question 291

Topic: Wrist & Carpus

Tears of the triangular fibrocartilage complex (TFCC) often occur in conjunction with distal radius fractures. Which zone of the TFCC is considered avascular and therefore has the poorest healing potential?

. Peripheral dorsal
. Peripheral volar
. Central articular
. Ulnar attachment at the fovea
. Radioulnar ligaments

Correct Answer & Explanation

. Peripheral dorsal

Explanation

The central articular disk of the TFCC is avascular, relying on synovial fluid for nutrition, and lacks healing potential. The peripheral portions have a blood supply and can be repaired.

Question 292

Topic: Wrist & Carpus

A 22-year-old male sustains a proximal pole scaphoid fracture. The high risk of avascular necrosis in this fracture pattern is due to the retrograde intraosseous blood supply. The primary vascular inflow to the scaphoid enters at which location?

. Distal pole via volar branches of the ulnar artery
. Dorsal ridge via branches of the radial artery
. Volar tubercle via the superficial palmar arch
. Scapholunate ligament attachments
. Radioscaphocapitate ligament attachments

Correct Answer & Explanation

. Distal pole via volar branches of the ulnar artery

Explanation

The major blood supply to the scaphoid enters distally along the dorsal ridge from branches of the radial artery, leaving the proximal pole dependent on tenuous retrograde flow.

Question 293

Topic: Wrist & Carpus

During clinical assessment of the distal radioulnar joint (DRUJ) for instability, understanding the tensioning of the radioulnar ligaments is essential. Which ligamentous structure is under maximum tension when the forearm is placed in full supination?

. Dorsal radioulnar ligament
. Volar radioulnar ligament
. Ulnar collateral ligament
. Radioscaphocapitate ligament
. Lunotriquetral ligament

Correct Answer & Explanation

. Dorsal radioulnar ligament

Explanation

The volar (palmar) radioulnar ligament of the TFCC is tightest in full supination, preventing dorsal translation of the ulna. Conversely, the dorsal radioulnar ligament becomes tightest in full pronation.

Question 294

Topic: Wrist & Carpus

The central band of the forearm interosseous membrane is essential for longitudinal load transfer. What is the anatomical orientation of its fibers?

. Proximal radius to distal ulna
. Proximal ulna to distal radius
. Transverse from radius to ulna
. Proximal radius to proximal ulna
. Distal radius to distal ulna

Correct Answer & Explanation

. Proximal radius to distal ulna

Explanation

The central band of the interosseous membrane runs obliquely from the proximal radius to the distal ulna. This orientation facilitates the transfer of axial loads from the radius to the ulna.

Question 295

Topic: Wrist & Carpus

The triangular fibrocartilage complex (TFCC) stabilizes the distal radioulnar joint (DRUJ). Which component is the primary restraint to dorsal translation of the distal ulna when the forearm is in pronation?

. Volar radioulnar ligament
. Dorsal radioulnar ligament
. Ulnocarpal meniscus
. Ulnolunate ligament
. Extensor carpi ulnaris subsheath

Correct Answer & Explanation

. Volar radioulnar ligament

Explanation

During forearm pronation, the dorsal radioulnar ligament becomes taut and acts as the primary restraint against dorsal translation of the distal ulna. Conversely, the volar radioulnar ligament tightens in supination.

Question 296

Topic: Wrist & Carpus

Six weeks after undergoing volar plating for a distal radius fracture, a patient notes a sudden inability to actively extend the interphalangeal joint of the thumb. The tendon most likely ruptured wraps around which bony prominence?

. Radial styloid
. Ulnar styloid
. Lister's tubercle
. Volar rim of the lunate fossa
. Scaphoid tubercle

Correct Answer & Explanation

. Radial styloid

Explanation

The extensor pollicis longus (EPL) tendon uses Lister's tubercle on the dorsal radius as a pulley. It can rupture due to mechanical attrition from prominent dorsal screws or biological factors following a distal radius fracture.

Question 297

Topic: Wrist & Carpus

The triangular fibrocartilage complex (TFCC) is the primary stabilizer of the distal radioulnar joint. Which portion of the articular disc has the best potential for healing after repair due to its rich vascularity?

. Central articular disc
. Volar radial attachment
. Dorsal radial attachment
. Peripheral ulnar attachment
. Radial sigmoid notch attachment

Correct Answer & Explanation

. Central articular disc

Explanation

The peripheral 10-20% of the TFCC, specifically its ulnar attachment, is well-vascularized by branches of the ulnar artery and anterior interosseous artery. This periphery has an excellent capacity to heal after surgical repair, whereas the central portion is avascular.

Question 298

Topic: Wrist & Carpus

A 65-year-old female experiences isolated rupture of the flexor pollicis longus (FPL) tendon following a volar plate fixation for a distal radius fracture. Which anatomical landmark on the distal radius is most commonly associated with FPL tendon attrition in this setting?

. Lister's tubercle
. Radial styloid
. Volar lip of the lunate fossa
. Watershed line
. Sigmoid notch

Correct Answer & Explanation

. Lister's tubercle

Explanation

The "watershed line" is a critical volar bony landmark on the distal radius. Placement of a volar plate distal to this line significantly increases the risk of flexor tendon irritation and subsequent rupture, most commonly the FPL.

Question 299

Topic: Wrist & Carpus

A 45-year-old woman develops a spontaneous rupture of the extensor pollicis longus (EPL) tendon following a nondisplaced distal radius fracture treated in a cast. Around which bony prominence does this tendon normally pivot, making it susceptible to attrition?

. Radial styloid
. Lister's tubercle
. Ulnar styloid
. Pisiform
. Hook of the hamate

Correct Answer & Explanation

. Radial styloid

Explanation

The EPL tendon travels in the 3rd dorsal extensor compartment and uses Lister's tubercle as a fulcrum to change direction toward the thumb. Callus formation or undisplaced fracture lines in this area can lead to attrition and rupture of the EPL.

Question 300

Topic: Wrist & Carpus

A patient complains of ulnar-sided wrist pain after a fall. MRI shows a tear of the foveal attachment of the Triangular Fibrocartilage Complex (TFCC). This specific attachment is critical for:

. Stabilizing the extensor carpi ulnaris tendon
. Providing primary longitudinal support to the carpus
. Maintaining stability of the distal radioulnar joint (DRUJ)
. Limiting radial deviation of the wrist
. Preventing volar subluxation of the lunate

Correct Answer & Explanation

. Stabilizing the extensor carpi ulnaris tendon

Explanation

The foveal attachment of the TFCC consists of the deep radioulnar ligaments, which converge on the fovea of the ulnar head. They are the primary stabilizers of the distal radioulnar joint (DRUJ).

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