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Wrist & Carpus MCQs

Practice Set 10 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 181

Topic: Wrist & Carpus



A 65-year-old female underwent volar locked plating for a comminuted distal radius fracture 6 months ago. The fracture has healed uneventfully. However, she now presents to the clinic with a sudden inability to actively flex the interphalangeal (IP) joint of her thumb. Which of the following technical errors during the index surgery most likely caused this complication?

. Over-penetration of the dorsal cortex with locking screws
. Placement of the volar plate distal to the watershed line
. Failure to repair the pronator quadratus over the plate
. Iatrogenic injury to the radial artery during the Henry approach
. Excessive volar tilt correction during reduction

Correct Answer & Explanation

. Placement of the volar plate distal to the watershed line

Explanation

The patient is presenting with a spontaneous rupture of the Flexor Pollicis Longus (FPL) tendon, which is a well-documented complication of volar plating of the distal radius. It is most commonly caused by iatrogenic plate prominence due to placement of the plate distal to the 'watershed line'. This creates attrition and friction on the FPL tendon as it glides over the prominent hardware, eventually leading to rupture. Prominent dorsal screws would endanger the extensor tendons (e.g., EPL).

Question 182

Topic: Wrist & Carpus
A 45-year-old man presents with wrist pain 10 years after an untreated scaphoid fracture. Radiographs show arthritis involving the entire radioscaphoid joint, but the capitolunate joint is completely preserved. What stage of Scaphoid Nonunion Advanced Collapse (SNAC) is this, and what is a recommended salvage procedure?
. SNAC Stage I; Radial styloidectomy and scaphoid fixation
. SNAC Stage II; Proximal row carpectomy or four-corner fusion
. SNAC Stage III; Total wrist arthrodesis
. SNAC Stage I; Proximal row carpectomy
. SNAC Stage II; Total wrist arthroplasty

Correct Answer & Explanation

. SNAC Stage II; Proximal row carpectomy or four-corner fusion

Explanation

SNAC staging: Stage I involves the radial styloid and distal scaphoid. Stage II involves the entire radioscaphoid fossa. Stage III involves the capitolunate (midcarpal) joint. Because the entire radioscaphoid joint is arthritic but midcarpal is spared, this is Stage II. Proximal row carpectomy (PRC) or four-corner fusion are standard recommended treatments.

Question 183

Topic: Wrist & Carpus

A 60-year-old woman undergoes volar locked plating for a comminuted, dorsally angulated distal radius fracture. Six weeks postoperatively, she suddenly loses the ability to actively extend her thumb interphalangeal joint. Rupture of the extensor pollicis longus (EPL) tendon in this scenario is most directly associated with which iatrogenic factor?

. Plate placement distal to the volar watershed line
. Over-distraction of the radiocarpal joint during reduction
. Prominent screw tips penetrating the dorsal cortex
. Use of a tourniquet for greater than 120 minutes
. Failure to repair the pronator quadratus

Correct Answer & Explanation

. Prominent screw tips penetrating the dorsal cortex

Explanation

EPL tendon rupture after volar locked plating of a distal radius fracture is most commonly caused by attrition from prominent screw tips penetrating the dorsal cortex. The EPL runs in the 3rd dorsal compartment, closely apposed to the dorsal cortex of the distal radius, making it highly vulnerable to protruding dorsal screws. Conversely, rupture of the flexor pollicis longus (FPL) tendon on the volar side is associated with prominent hardware placed distal to the volar watershed line.

Question 184

Topic: Wrist & Carpus
Review the clinical image. What is the earliest radiographic change expected in the natural progression of Scaphoid Nonunion Advanced Collapse (SNAC) if left untreated?
. Radioscaphoid joint arthritis (radial styloid)
. Capitolunate joint arthritis
. Scaphotrapezial joint arthritis
. Radiolunate joint arthritis
. Ulnocarpal arthritis

Correct Answer & Explanation

. Radioscaphoid joint arthritis (radial styloid)

Explanation

Scaphoid Nonunion Advanced Collapse (SNAC) follows a predictable pattern of degenerative changes. Stage I involves arthritis isolated to the articulation between the scaphoid and the radial styloid. Stage II progresses to involve the entire radioscaphoid joint. Stage III involves the capitolunate joint. The radiolunate joint is characteristically spared because the lunate fossa cartilage remains concentric with the lunate.

Question 185

Topic: Wrist & Carpus
A 45-year-old manual laborer presents with chronic, progressive right wrist pain. Radiographs demonstrate a nonunion of the scaphoid with advanced arthritic changes narrowing the radioscaphoid articulation as well as the scaphocapitate joint. The radiolunate joint is completely preserved. What is the correct classification and an appropriate surgical treatment for this condition?
. SNAC I; Radial styloidectomy
. SNAC II; Proximal row carpectomy
. SNAC III; Scaphoid excision and 4-corner fusion
. SNAC III; Total wrist arthrodesis
. SLAC II; Scapholunate ligament repair

Correct Answer & Explanation

. SNAC II; Proximal row carpectomy

Explanation

Scaphoid Nonunion Advanced Collapse (SNAC) progresses in a predictable pattern. SNAC I involves only the radial styloid and distal scaphoid pole. SNAC II involves the entire radioscaphoid joint and the scaphocapitate joint. SNAC III progresses to periscaphoid arthritis (including the capitolunate joint). The radiolunate joint is characteristically spared. A condition involving the radioscaphoid and scaphocapitate joints is SNAC II. Acceptable salvage procedures for SNAC II include proximal row carpectomy (PRC) or scaphoid excision with 4-corner fusion.

Question 186

Topic: Wrist & Carpus
A 45-year-old man presents with chronic wrist pain and a history of a scaphoid fracture 10 years ago. Radiographs demonstrate a scaphoid nonunion. There is radioscaphoid arthritis and narrowing of the scaphocapitate joint, but the lunocapitate and radiolunate joints are completely preserved. According to the Scaphoid Nonunion Advanced Collapse (SNAC) classification, what is the stage of his arthritis?
. Stage I
. Stage II
. Stage III
. Stage IV
. Stage V

Correct Answer & Explanation

. Stage II

Explanation

SNAC arthritis staging progresses predictably based on altered kinematics. Stage I involves arthritis localized to the radial styloid and the distal scaphoid fragment. Stage II progresses to involve the scaphocapitate joint. Stage III involves the lunocapitate joint. The radiolunate joint is uniquely spared in both SLAC and SNAC wrists due to the spherical congruency of the lunate fossa.

Question 187

Topic: Wrist & Carpus

An otherwise healthy 26-year-old woman is involved in a high speed motor vehicle accident and sustains the injury shown in Figure 54 to her dominant right arm. Appropriate treatment of this injury complex includes

General Orthopedics Board Review 2026: High-Yield MCQs (Set 4) - Figure 43

. plating of the radial shaft fracture and open repair of the triangular fibrocartilage complex.
. open reduction and internal fixation of the radius and ulna.
. plating of the radius with closed reduction and evaluation of the distal radioulnar joint (DRUJ).
. closed reduction of the radius and DRUJ.
. plating of the radius and pinning of the DRUJ in pronation.

Correct Answer & Explanation

. plating of the radius with closed reduction and evaluation of the distal radioulnar joint (DRUJ).

Explanation

This Galeazzi fracture is an injury that requires surgical treatment in an adult. The algorithm includes anatomic reduction of the radial shaft and closed reduction of the DRUJ with assessment of stability. If the DRUJ remains unstable, supination of the wrist may reduce the DRUJ. If not, either open or closed reduction with pinning is undertaken. The closer the radius fracture is to the DRUJ, the more likely it is to be unstable.

Question 188

Topic: Wrist & Carpus

In the surgical treatment of complex intra-articular distal radius fractures, a volar marginal fragment involving the lunate facet (the 'lunate drop-out' or 'Melone' fragment) is notoriously difficult to capture with standard fixed-angle volar locking plates. Failure to secure this specific fragment most commonly results in which of the following complications?

. Dorsal subluxation of the entire carpus.
. Volar subluxation of the carpus.
. Avascular necrosis of the scaphoid.
. Rupture of the extensor pollicis longus (EPL) tendon.
. Proximal migration of the radius resulting in ulnar positive variance.

Correct Answer & Explanation

. Volar subluxation of the carpus.

Explanation

The volar lunate facet fragment provides critical bony support for the strong short radiolunate ligament. Because this ligament remains attached to the fragment, if the fragment is not anatomically secured (e.g., if a volar plate is placed too proximally to buttress it), the lunate—and consequently the rest of the carpus—will subluxate or dislocate volarly off the distal radius. This catastrophic failure is a well-known complication of inadequately fixing the volar lunate facet.

Question 189

Topic: Wrist & Carpus

A 55-year-old female presents with a sudden inability to actively flex the interphalangeal joint of her right thumb, 8 months after undergoing open reduction and internal fixation of a distal radius fracture with a volar locking plate.

What technical error during the initial surgery most likely caused this complication?

. Placement of screws past the dorsal cortex
. Positioning the plate distal to the watershed line
. Failure to repair the pronator quadratus
. Over-reduction of the volar tilt
. Injury to the anterior interosseous nerve during the surgical approach

Correct Answer & Explanation

. Positioning the plate distal to the watershed line

Explanation

Attritional rupture of the flexor pollicis longus (FPL) tendon is a classic complication of volar plating for distal radius fractures. It is most commonly caused by positioning the plate too distally, allowing prominent hardware beyond the watershed line to cause friction and eventual tendon failure.

Question 190

Topic: Wrist & Carpus

A 45-year-old female presents with a chronic, progressively worsening painful wrist, especially on the ulnar side. X-rays show positive ulnar variance and degenerative changes at the distal radioulnar joint (DRUJ) and ulnocarpal articulation. Which condition is most likely?

. Kienbock's disease
. Preiser's disease
. TFCC tear
. Ulnar Impaction Syndrome
. Scapholunate Advanced Collapse (SLAC)

Correct Answer & Explanation

. Ulnar Impaction Syndrome

Explanation

Ulnar impaction syndrome (also known as ulnar abutment syndrome) is caused by repetitive loading and degenerative changes between the ulnar head, TFCC, lunate, and triquetrum, often associated with positive ulnar variance. This results in ulnar-sided wrist pain. Kienbock's disease is avascular necrosis of the lunate. Preiser's disease is avascular necrosis of the scaphoid. A TFCC tear can cause ulnar pain but is often a component of ulnar impaction or can occur in isolation. SLAC wrist involves scapholunate ligament disruption and subsequent arthritis, typically radial-sided initially.

Question 191

Topic: Wrist & Carpus

Which of the following ligaments is considered the most important stabilizer of the distal radioulnar joint (DRUJ)?

. Palmar radiocarpal ligament
. Dorsal radiocarpal ligament
. Ulnar collateral ligament of wrist
. Radial collateral ligament of wrist
. Triangular Fibrocartilage Complex (TFCC)

Correct Answer & Explanation

. Triangular Fibrocartilage Complex (TFCC)

Explanation

The Triangular Fibrocartilage Complex (TFCC) is the primary stabilizer of the DRUJ and the ulnar side of the wrist. It consists of the articular disc, dorsal and volar radioulnar ligaments, and the meniscal homologue. The radiocarpal and ulnar/radial collateral ligaments primarily stabilize the radiocarpal joint but have less direct influence on DRUJ stability.

Question 192

Topic: Wrist & Carpus

A 25-year-old weightlifter presents with ulnar-sided wrist pain, worse with gripping and pronation/supination. Examination reveals tenderness over the distal ulna and a positive 'fovea sign' (tenderness in the depression between the ulnar styloid and flexor carpi ulnaris tendon). Which of the following is the most likely diagnosis?

. Pisotriquetral arthritis
. Ulnar collateral ligament sprain
. Triangular Fibrocartilage Complex (TFCC) tear
. Extensor Carpi Ulnaris (ECU) subluxation
. Lunotriquetral instability

Correct Answer & Explanation

. Triangular Fibrocartilage Complex (TFCC) tear

Explanation

The clinical presentation, particularly the ulnar-sided wrist pain exacerbated by gripping and pronation/supination, and a positive fovea sign, are highly indicative of a Triangular Fibrocartilage Complex (TFCC) tear. The TFCC is a primary stabilizer of the DRUJ and the ulnar carpus. Pisotriquetral arthritis causes pain more volar and distal. Ulnar collateral ligament sprains are less common in the wrist itself. ECU subluxation often presents with snapping. Lunotriquetral instability also causes ulnar-sided pain, but the fovea sign is more specific to TFCC.

Question 193

Topic: Wrist & Carpus
According to Mayfield's progressive perilunar instability, what is the final stage (Stage IV) of the sequence?
. Scapholunate dissociation
. Lunotriquetral disruption
. Dorsal perilunate dislocation
. Volar lunate dislocation
. Capitate fracture

Correct Answer & Explanation

. Volar lunate dislocation

Explanation

Mayfield's stages describe a predictable pattern of ligamentous injury around the lunate. Stage I is scapholunate dissociation, Stage II includes capitate dislocation, Stage III is perilunate dislocation, and Stage IV is a volar lunate dislocation.

Question 194

Topic: Wrist & Carpus

A 45-year-old female treated non-operatively for a minimally displaced distal radius fracture presents 6 weeks later with a sudden inability to actively extend her thumb interphalangeal joint. What is the most appropriate management?

. Primary repair of the extensor pollicis longus (EPL) tendon
. Tendon transfer using the extensor indicis proprius (EIP)
. Tenolysis of the first dorsal compartment
. Tendon transfer using the extensor carpi radialis longus (ECRL)
. Tendon graft using palmaris longus

Correct Answer & Explanation

. Tendon transfer using the extensor indicis proprius (EIP)

Explanation

EPL rupture is a known complication of nondisplaced or minimally displaced distal radius fractures due to attrition and ischemia. Because the tendon ends are typically frayed and retracted, EIP to EPL transfer is the preferred surgical treatment.

Question 195

Topic: Wrist & Carpus

A 42-year-old female sustained a nondisplaced distal radius fracture treated conservatively in a cast. Six weeks later, she suddenly loses the ability to actively extend her thumb interphalangeal joint. What is the preferred surgical management for this complication?

. Primary end-to-end tendon repair
. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) transfer
. Palmaris longus (PL) to extensor pollicis longus (EPL) transfer
. Flexor carpi radialis (FCR) to extensor pollicis longus (EPL) transfer
. Tenodesis of the EPL to the extensor carpi radialis brevis (ECRB)

Correct Answer & Explanation

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

Explanation

This patient has an EPL rupture due to ischemic attrition at the watershed area or friction over a bony spike following a distal radius fracture. Primary repair is usually impossible due to tendon retraction and degeneration, making an EIP to EPL tendon transfer the gold standard treatment.

Question 196

Topic: Wrist & Carpus
According to Mayfield's progressive perilunate instability classification, which of the following represents the correct sequential sequence of ligamentous failure ending in a lunate dislocation?
. Scapholunate -> Lunotriquetral -> Capitolunate -> Volar radiolunate
. Lunotriquetral -> Capitolunate -> Scapholunate -> Dorsal radiolunate
. Scapholunate -> Capitolunate -> Lunotriquetral -> Dorsal radiocarpal
. Scapholunate -> Capitolunate -> Lunotriquetral -> Volar radiocarpal
. Capitolunate -> Scapholunate -> Lunotriquetral -> Volar radiolunate

Correct Answer & Explanation

. Scapholunate -> Capitolunate -> Lunotriquetral -> Volar radiocarpal

Explanation

Mayfield's stages of perilunate instability occur in a distinct sequence: Stage I (Scapholunate), Stage II (Capitolunate), Stage III (Lunotriquetral), and Stage IV (Lunate dislocation, failing the dorsal radiocarpal ligaments and displacing volarly).

Question 197

Topic: Wrist & Carpus
A 29-year-old male presents with dorsal wrist pain. X-rays reveal Lichtman Stage IIIA Kienbock's disease with a negative ulnar variance of 3 mm. What is the most appropriate joint-leveling procedure to unload the lunate?
. Proximal row carpectomy
. Ulnar lengthening osteotomy
. Radial shortening osteotomy
. Capitate shortening osteotomy
. Scaphoid excision and four-corner fusion

Correct Answer & Explanation

. Radial shortening osteotomy

Explanation

In early stages of Kienbock's disease (Stages I-IIIA) with negative ulnar variance, joint-leveling procedures are indicated to unload the lunate. Radial shortening osteotomy is the gold standard as it is technically easier and has lower nonunion rates than ulnar lengthening.

Question 198

Topic: Wrist & Carpus

A 32-year-old male presents with a rigid, isolated volar dislocation of the distal radioulnar joint (DRUJ) following a hyperpronation injury. Attempted closed reduction is unsuccessful. What anatomical structure is most commonly responsible for blocking the closed reduction of a volar DRUJ dislocation?

. Extensor carpi ulnaris (ECU) tendon
. Pronator quadratus muscle
. Triangular fibrocartilage complex (TFCC)
. Ulnar nerve
. Flexor digitorum profundus (FDP) tendons

Correct Answer & Explanation

. Pronator quadratus muscle

Explanation

In a volar dislocation of the DRUJ, the ulnar head displaces volarly. The pronator quadratus is frequently the structure that entraps the ulnar head, acting as a soft tissue interposition that blocks closed reduction.

Question 199

Topic: Wrist & Carpus
A 32-year-old male presents with chronic dorsal wrist pain and decreased grip strength. Radiographs demonstrate sclerosis and early collapse of the lunate, with a negative ulnar variance of 3 mm. There is no evidence of radiocarpal or midcarpal arthritis. Which of the following is the most appropriate surgical management?
. Proximal row carpectomy
. Radial shortening osteotomy
. Four-corner fusion
. Lunate excision and silastic replacement
. Ulnar lengthening osteotomy

Correct Answer & Explanation

. Radial shortening osteotomy

Explanation

This patient has Stage IIIA Kienbock's disease with negative ulnar variance. A joint-leveling procedure, such as a radial shortening osteotomy, offloads the radiolunate joint and is the treatment of choice before the onset of degenerative arthritis.

Question 200

Topic: Wrist & Carpus

A 45-year-old female presents with sudden inability to actively extend the interphalangeal joint of her thumb. Six weeks prior, she sustained a nondisplaced distal radius fracture treated in a cast. What is the most reliable surgical option to restore thumb extension?

. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Primary end-to-end repair of the EPL tendon
. Palmaris longus interposition graft
. Extensor carpi radialis longus (ECRL) to EPL transfer
. Abductor pollicis longus (APL) transfer to EPL

Correct Answer & Explanation

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

Explanation

Delayed EPL rupture after a nondisplaced distal radius fracture is due to vascular ischemia or mechanical attrition in Lister's tubercle. Primary repair is rarely possible due to tendon retraction and degeneration, making an EIP to EPL tendon transfer the gold standard treatment.

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