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Wrist & Carpus MCQs

Practice Set 1 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 1

Topic: Wrist & Carpus

Following open reduction and internal fixation of a distal radius fracture with a volar locking plate, a patient develops an inability to actively flex the interphalangeal joint of the thumb 6 months postoperatively. What technical error is most likely responsible?

. Placement of the plate proximal to the watershed line
. Placement of the plate distal to the watershed line
. Penetration of screws into the dorsal radiocarpal joint
. Over-reduction of the volar tilt
. Failure to repair the pronator quadratus

Correct Answer & Explanation

. Placement of the plate distal to the watershed line

Explanation

Placement of a volar plate distal to the watershed line of the distal radius can cause mechanical irritation and subsequent attrition rupture of the flexor pollicis longus (FPL) tendon.

Question 2

Topic: Wrist & Carpus

The primary stabilizer of the distal radioulnar joint (DRUJ) during forearm supination is the:

. Volar radioulnar ligament
. Dorsal radioulnar ligament
. Extensor carpi ulnaris subsheath
. Interosseous membrane
. Ulnocarpal ligaments

Correct Answer & Explanation

. Volar radioulnar ligament

Explanation

During supination, the volar radioulnar ligament becomes taut and serves as the primary stabilizer of the DRUJ. In contrast, the dorsal radioulnar ligament is the primary restraint during pronation.

Question 3

Topic: Wrist & Carpus

Failure to stabilize the volar lunate facet fragment in a distal radius fracture most commonly leads to subluxation of the carpus in which direction?

. Dorsal
. Volar
. Ulnar
. Radial
. Proximal

Correct Answer & Explanation

. Volar

Explanation

The volar lunate facet is critical for the stability of the radiocarpal joint due to the attachment of the short radiolunate ligament. Failure to capture this fragment often results in volar subluxation of the carpus and catastrophic joint failure.

Question 4

Topic: Wrist & Carpus

In the management of a Galeazzi fracture, which of the following radiographic signs most strongly indicates gross instability of the distal radioulnar joint (DRUJ) requiring operative stabilization?

. Fracture of the radial shaft greater than 7.5 cm from the articular surface
. Volar apex angulation of the radius
. Widening of the DRUJ on the true PA radiograph
. Fracture at the base of the ulnar styloid
. Dorsal comminution of the radius

Correct Answer & Explanation

. Fracture at the base of the ulnar styloid

Explanation

A basilar ulnar styloid fracture in the setting of a Galeazzi fracture frequently signifies complete detachment of the triangular fibrocartilage complex (TFCC) from its foveal insertion. This indicates severe DRUJ instability that often requires pinning or direct repair.

Question 5

Topic: Wrist & Carpus

Which of the following is the most common complication after a posttraumatic distal radial growth arrest:

. Positive distal ulnar variance
. Negative distal ulnar variance
. Increased distal radial articular angle
. Decreased distal radial articular angle
. Distal radioulnar joint instability

Correct Answer & Explanation

. Positive distal ulnar variance

Explanation

The most common complication after a posttraumatic distal radial growth arrest is positive ulnar variance (overgrowth). Other complications may include decreased distal radial articular angle, triradiate fibrocartilage tear, or distal radioulnar joint instability, but they are less common. Increased radial articular angle and negative ulnar variance rarely develop after these injuries.

Question 6

Topic: Wrist & Carpus

A patient undergoes volar plating for a distal radius fracture. Six months later, the patient cannot actively flex the interphalangeal joint of the thumb. What technical error during the initial surgery is the most likely cause?

. Placing the plate proximal to the watershed line
. Placing the plate distal to the watershed line
. Penetration of the dorsal cortex with screws
. Failure to repair the pronator quadratus
. Over-reduction of the volar tilt

Correct Answer & Explanation

. Placing the plate distal to the watershed line

Explanation

Rupture of the flexor pollicis longus (FPL) tendon is a known complication of volar distal radius plating. It most commonly occurs when the plate is placed too distally, crossing the "watershed line," causing mechanical attrition of the tendon.

Question 7

Topic: Wrist & Carpus

A 65-year-old female undergoes volar locked plating for a comminuted distal radius fracture. Postoperatively, she develops an inability to actively flex the interphalangeal joint of her thumb. Which tendon is most likely injured?

. Extensor pollicis longus (EPL)
. Flexor pollicis longus (FPL)
. Flexor carpi radialis (FCR)
. Abductor pollicis longus (APL)
. Extensor pollicis brevis (EPB)

Correct Answer & Explanation

. Flexor pollicis longus (FPL)

Explanation

The flexor pollicis longus (FPL) tendon is at risk of attrition and rupture from prominent hardware on the volar aspect of the distal radius. Loss of active interphalangeal joint flexion confirms FPL injury.

Question 8

Topic: Wrist & Carpus

Six weeks following a minimally displaced Colles' fracture treated in a short arm cast, a 65-year-old woman presents unable to actively extend the interphalangeal joint of her thumb. She recalls a sudden painless pop the previous day. What is the most appropriate surgical treatment?

. Direct end-to-end repair of the ruptured tendon
. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Extensor carpi radialis longus (ECRL) to EPL tendon transfer
. Free tendon graft using the palmaris longus
. Thumb interphalangeal joint arthrodesis

Correct Answer & Explanation

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

Explanation

Delayed rupture of the EPL following a distal radius fracture leaves degenerated and retracted tendon ends, rendering direct repair impossible. An EIP to EPL tendon transfer is the gold standard treatment for restoration of function.

Question 9

Topic: Wrist & Carpus

A 60-year-old woman sustains a distal radius fracture treated with closed reduction and casting. Which of the following daily oral supplements has the highest level of evidence for reducing her risk of developing Complex Regional Pain Syndrome (CRPS)?

. Vitamin D
. Calcium carbonate
. Vitamin C
. Magnesium sulfate
. Glucosamine

Correct Answer & Explanation

. Vitamin C

Explanation

Vitamin C (typically 500 mg daily for 50 days) has been shown in randomized trials to reduce the incidence of CRPS following distal radius fractures. It acts as an antioxidant mitigating the excessive inflammatory response.

Question 10

Topic: Wrist & Carpus

Six weeks after non-operative management of a non-displaced distal radius fracture, a 60-year-old female presents with a sudden inability to actively extend the interphalangeal joint of her thumb. What is the most appropriate surgical treatment?

. Primary end-to-end repair of the ruptured tendon
. Tendon transfer using the extensor indicis proprius (EIP)
. Tendon transfer using the palmaris longus (PL)
. Tendon graft using the plantaris tendon
. Tenodesis of the distal stump to the first dorsal compartment

Correct Answer & Explanation

. Tendon transfer using the extensor indicis proprius (EIP)

Explanation

Extensor pollicis longus (EPL) rupture is a known complication of non-displaced distal radius fractures due to attrition and localized ischemia. Primary repair is usually impossible due to tendon retraction and fraying, making EIP to EPL transfer the treatment of choice.

Question 11

Topic: Wrist & Carpus

During a posterior (dorsal) approach to percutaneous screw fixation for a scaphoid fracture, many structures are close to the guidewire insertion location and are at risk for injury. Which of the following structures is the closest to the guidewire insertion location according to a recent cadaveric study:

. Posterior interosseous nerve
. Extensor digitorum communis to the index
. Extensor indicis proprius
. Extensor carpi radialis brevis
. Extensor digitorum communis to the index and posterior interosseous nerve

Correct Answer & Explanation

. Extensor digitorum communis to the index and posterior interosseous nerve

Explanation

Adamany and colleagues performed a cadaveric study to evaluate the dorsal structures at risk with truly percutaneous headless screw placement for scaphoid fractures. They noted that the posterior interosseous nerve and the extensor digitorum communis to the index finger were an average of 2.2 mm from the guidewire and therefore at greatest risk from this approach.

Question 12

Topic: Wrist & Carpus

A 28-year-old manual laborer presents with dorsal wrist pain. Radiographs reveal sclerosis and fragmentation of the lunate (Kienbock's disease). Which of the following radiographic anatomical variants is most highly associated with this condition?

. Positive ulnar variance
. Negative ulnar variance
. Type II lunate morphology
. Dorsal intercalated segment instability (DISI)
. Madelung deformity

Correct Answer & Explanation

. Negative ulnar variance

Explanation

Negative ulnar variance is strongly associated with Kienbock's disease. The shortened ulna relative to the radius leads to increased radiolunate contact stresses, precipitating lunate avascular necrosis.

Question 13

Topic: Wrist & Carpus

A 28-year-old male sustains a Galeazzi fracture. Following rigid plate fixation of the radial shaft, the distal radioulnar joint (DRUJ) is noted to be highly unstable in supination but stable in pronation. What is the most appropriate next step in management?

. Immobilization in a long arm cast in supination
. Immobilization in a long arm cast in neutral
. Percutaneous pinning of the DRUJ in supination
. Percutaneous pinning of the DRUJ in pronation
. Open reduction of the DRUJ with ulnar styloid excision

Correct Answer & Explanation

. Immobilization in a long arm cast in supination

Explanation

If the DRUJ remains unstable after rigid anatomical fixation of the radius in a Galeazzi fracture, it should be pinned in the position of maximum stability. If it is unstable in supination (and stable in pronation), pinning the DRUJ in the stable position or supination depending on reducibility is required to allow ligamentous healing.

Question 14

Topic: Wrist & Carpus

An adult patient undergoes rigid plate fixation of the radial shaft for a Galeazzi fracture. Intraoperatively, following radius fixation, the distal radioulnar joint (DRUJ) is tested and found to be grossly unstable in all forearm positions (pronation, neutral, and supination). What is the most appropriate next step in management?

. Immobilization in a long arm cast in supination
. Transverse K-wire fixation of the DRUJ in neutral or supination
. Darrach procedure
. Suave-Kapandji procedure
. Early active range of motion in a functional brace

Correct Answer & Explanation

. Transverse K-wire fixation of the DRUJ in neutral or supination

Explanation

If the DRUJ remains grossly unstable in all positions after anatomic fixation of the radius in a Galeazzi fracture, the joint should be reduced and percutaneously pinned with K-wires (ulna to radius) for 4-6 weeks to allow the triangular fibrocartilage complex (TFCC) to heal.

Question 15

Topic: Wrist & Carpus

Injuries to the central articular disk portion of the triangular fibrocartilage complex are related to all of the following except:

. Age
. Positive ulnar variance
. Ulnocarpal impingement
. Scaphoid nonunion
. Avulsion injuries from the dorsal ligamentous attachments

Correct Answer & Explanation

. Positive ulnar variance

Explanation

Scaphoid nonunion is not related to central triangular fibrocartilage complex injuries. A positive ulnar variance is most strongly associated with triangular fibrocartilage complex central disk injuries.

Question 16

Topic: Wrist & Carpus

A 62-year-old woman sustained a nondisplaced distal radius fracture treated in a cast for 4 weeks. Six weeks after cast removal, she reports a sudden inability to extend her thumb at the interphalangeal joint. What is the most appropriate definitive management for her current condition?

. Primary end-to-end tendon repair
. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Tendon graft using palmaris longus
. Flexor carpi radialis (FCR) to EPL tendon transfer
. Corticosteroid injection and extension splinting

Correct Answer & Explanation

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

Explanation

Delayed extensor pollicis longus (EPL) rupture after a nondisplaced distal radius fracture is best treated with an extensor indicis proprius (EIP) to EPL tendon transfer. Primary repair is typically not feasible due to retracted and degenerated tendon ends.

Question 17

Topic: Wrist & Carpus
A 24-year-old male is diagnosed with a stage III perilunate dislocation according to Mayfield's classification. Which intercarpal ligamentous connection or joint is disrupted at this stage?
. Scapholunate
. Lunocapitate
. Lunotriquetral
. Radiolunate
. Trapeziometacarpal

Correct Answer & Explanation

. Scapholunate

Explanation

Mayfield staging of perilunate instability progresses from radial to ulnar. Stage I is scapholunate disruption; Stage II is lunocapitate disruption; Stage III is lunotriquetral disruption; and Stage IV is lunate dislocation (radiolunate failure).

Question 18

Topic: Wrist & Carpus

A 25-year-old patient presents with persistent anatomical snuffbox tenderness after a FOOSH injury. Initial plain radiographs are negative for a scaphoid fracture.

According to current literature and guidelines, which advanced imaging modality has demonstrated superior diagnostic accuracy over plain radiographs and bone scans for detecting occult scaphoid fractures?

. Computed Tomography (CT) Scan
. Magnetic Resonance Imaging (MRI)
. Diagnostic Ultrasound
. Arthrography
. Fluoroscopy with stress views

Correct Answer & Explanation

. Magnetic Resonance Imaging (MRI)

Explanation

Correct Answer: BThe text states under "Diagnostic Algorithms": "MRI is highly sensitive for occult fractures and bone contusions...Meta-analyses have demonstrated the superior diagnostic accuracy of MRI over plain radiographs and bone scans for occult scaphoid fractures." This directly supports MRI as the superior modality for detecting occult fractures when initial radiographs are negative.Incorrect Options:A) Computed Tomography (CT) Scan:While CT is the gold standard for assessing fracture displacement, comminution, and fragment orientation for surgical planning, MRI is generally considered more sensitive for detecting occult fractures (bone edema/contusion) not visible on initial radiographs or even early CT.C) Diagnostic Ultrasound:Ultrasound has limited diagnostic accuracy for scaphoid fractures, especially occult ones, compared to MRI or CT.D) Arthrography:Arthrography is primarily used to assess ligamentous injuries and cartilage integrity, not for diagnosing occult bone fractures.E) Fluoroscopy with stress views:Fluoroscopy is used intraoperatively for guiding fixation or dynamically assessing carpal instability, but it is not an advanced imaging modality for detecting occult fractures.

Question 19

Topic: Wrist & Carpus

A 24-year-old male sustains a proximal pole scaphoid fracture. Which of the following surgical approaches and screw trajectories offers the best biomechanical stability and biological preservation for this specific injury?

. Volar approach, eccentric screw placement
. Volar approach, central-central screw placement
. Dorsal approach, central-central screw placement
. Dorsal approach, eccentric screw placement
. Lateral approach, divergent screw placement

Correct Answer & Explanation

. Dorsal approach, central-central screw placement

Explanation

For proximal pole scaphoid fractures, a dorsal approach is preferred as it avoids dividing the critical volar radioscaphocapitate ligament and allows for direct, central-central screw placement which biomechanically provides the greatest load to failure.

Question 20

Topic: Wrist & Carpus

When performing internal fixation of a proximal pole scaphoid fracture, which surgical approach provides the most direct access for optimal screw trajectory without violating the radiocarpal articular surface?

. Volar approach through the bed of the flexor carpi radialis (FCR)
. Dorsal approach between the third and fourth extensor compartments
. Mid-lateral radial approach through the anatomic snuffbox
. Volar approach between the radial artery and FCR
. Dorsal approach between the first and second extensor compartments

Correct Answer & Explanation

. Dorsal approach between the third and fourth extensor compartments

Explanation

The dorsal approach (often utilizing the interval between the 3rd and 4th compartments) is preferred for proximal pole scaphoid fractures. It allows central screw placement directly down the longitudinal axis of the scaphoid without damaging the articular surface.

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