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Wrist & Carpus MCQs

Practice Set 4 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 61

Topic: Wrist & Carpus

A 55-year-old active patient undergoes open reduction and internal fixation of a comminuted distal radius fracture with a volar locking plate. Post-fixation fluoroscopy confirms excellent restoration of radial length, radial inclination, and volar tilt. However, during intraoperative assessment, the surgeon notes persistent dorsal subluxation of the ulnar head relative to the sigmoid notch during forearm rotation, despite adequate radial reduction. Which of the following is the MOST appropriate next step in management?

. Proceed with wound closure, as DRUJ instability often resolves spontaneously after distal radius fixation.
. Apply a long arm cast with the forearm in full supination to stabilize the DRUJ.
. Perform a temporary DRUJ stabilization with K-wires, typically with the forearm in neutral rotation.
. Perform an ulnar shortening osteotomy to address the positive ulnar variance.
. Remove the volar plate and re-reduce the distal radius, suspecting an inadequate reduction.

Correct Answer & Explanation

. Perform a temporary DRUJ stabilization with K-wires, typically with the forearm in neutral rotation.

Explanation

Correct Answer: CThe case explicitly states: 'After plate fixation, meticulous assessment of potential DRUJ and carpal instability is paramount. ... If unstable, consider intraoperative TFCC repair (via arthroscopy or open approach), or K-wire stabilization of the DRUJ (typically 2 K-wires across the DRUJ, with the forearm in neutral rotation).' Persistent DRUJ instability after anatomical reduction of the distal radius indicates a significant TFCC injury or gross incongruity that requires direct intervention. Temporary K-wire stabilization in neutral rotation is a common and effective method to allow the TFCC to heal in a reduced position, preventing chronic instability and subsequent arthritis.Option A is incorrect. Unaddressed DRUJ instability leads to chronic pain, restricted forearm rotation, and early degenerative changes, directly impacting long-term function and increasing CRPS risk.Option B is incorrect. While immobilization is needed, full supination can put stress on the DRUJ ligaments and may not be the optimal position for healing, especially if the instability is dorsal. Neutral rotation is generally preferred for DRUJ stabilization.Option D is incorrect. An ulnar shortening osteotomy is a salvage procedure for chronic positive ulnar variance and ulnar impaction syndrome, not an acute treatment for intraoperative DRUJ instability after radial length has been restored. The problem here is instability, not necessarily positive ulnar variance if radial length is restored.Option E is incorrect. The question states 'excellent restoration of radial length, radial inclination, and volar tilt,' implying the distal radius reduction is adequate. Removing the plate would be unnecessary and detrimental.

Question 62

Topic: Wrist & Carpus

A 48-year-old carpenter sustains a displaced, comminuted distal radius fracture with significant loss of volar tilt and radial shortening. He undergoes open reduction and internal fixation with a volar locking plate. During the procedure, after plate application, the surgeon uses fluoroscopy to confirm optimal screw length and trajectory. Which of the following fluoroscopic findings, if present, would indicate an immediate need for screw revision?

. A distal screw tip extending 1 mm beyond the dorsal cortex.
. A distal screw tip extending 2 mm into the subchondral bone.
. A proximal screw engaging both cortices of the radial shaft.
. A distal screw trajectory parallel to the articular surface.
. A distal screw tip positioned just proximal to the critical watershed line.

Correct Answer & Explanation

. A distal screw tip extending 1 mm beyond the dorsal cortex.

Explanation

Correct Answer: AThe case states: 'Fluoroscopy in both AP and lateral views is crucial to confirm optimal screw length and trajectory, ensuring screws do not violate the joint space or protrude dorsally.' A screw tip extending 1 mm beyond the dorsal cortex, while seemingly small, constitutes dorsal protrusion. This can lead to significant complications such as extensor tendon irritation, tenosynovitis, or even rupture, especially for the extensor pollicis longus (EPL) tendon which courses over Lister's tubercle dorsally. Therefore, any dorsal protrusion requires immediate revision.Option B (2 mm into the subchondral bone) is generally acceptable and desired, as distal screws are designed to buttress the articular surface by engaging the subchondral bone for stable fixation.Option C (Proximal screw engaging both cortices) is the standard for cortical screws in the shaft, providing robust fixation.Option D (Distal screw trajectory parallel to the articular surface) is often ideal for maximizing subchondral bone purchase without violating the joint.Option E (Distal screw tip positioned just proximal to the critical watershed line) refers to plate positioning, not screw tip position. The plate's distal edge should be just proximal to the watershed line to maximize subchondral screw support without impinging on flexor tendons. Screw tips should be within the bone, not violating the joint or protruding dorsally.

Question 63

Topic: Wrist & Carpus

A 40-year-old patient undergoes open reduction and internal fixation of a distal radius fracture. Six months post-operatively, the patient presents with chronic pain, limited forearm rotation, and a clicking sensation on the ulnar side of the wrist. Radiographs show a healed distal radius fracture with neutral ulnar variance. Physical examination reveals tenderness over the DRUJ and instability on stress testing. Based on the case, which of the following is the MOST likely underlying cause of the patient's symptoms?

. Persistent positive ulnar variance leading to ulnar impaction syndrome.
. Unaddressed scapholunate ligament dissociation.
. Chronic flexor pollicis longus (FPL) tendon rupture.
. Unrecognized or inadequately treated triangular fibrocartilage complex (TFCC) injury.
. Post-traumatic arthritis of the radiocarpal joint due to articular step-off.

Correct Answer & Explanation

. Unrecognized or inadequately treated triangular fibrocartilage complex (TFCC) injury.

Explanation

Correct Answer: DThe patient's symptoms of chronic pain, limited forearm rotation, clicking, and DRUJ instability, despite a healed distal radius fracture and neutral ulnar variance, strongly point to an issue with the DRUJ stabilizers. The case highlights: 'The DRUJ is a complex trochoid joint critical for forearm rotation. It is formed by the ulnar head articulating with the sigmoid notch of the distal radius. Stability is primarily conferred by the triangular fibrocartilage complex (TFCC)... Unaddressed DRUJ instability leads to chronic pain, restricted forearm rotation, and early degenerative changes.' An unrecognized or inadequately treated TFCC injury during the initial fracture management would lead to these chronic DRUJ symptoms.Option A (Persistent positive ulnar variance) is incorrect because the radiographs show neutral ulnar variance. Positive ulnar variance is a common cause of DRUJ pathology, but it's ruled out here.Option B (Unaddressed scapholunate ligament dissociation) would primarily cause carpal instability and pain, often with a dorsal intercalated segmental instability (DISI) deformity, but less directly explain isolated DRUJ instability and limited forearm rotation.Option C (Chronic FPL tendon rupture) would cause loss of thumb IP flexion, not DRUJ instability or limited forearm rotation.Option E (Post-traumatic arthritis of the radiocarpal joint) would cause generalized wrist pain and stiffness, but the specific symptoms of clicking and instability on the ulnar side, with limited forearm rotation, are more characteristic of DRUJ pathology rather than primary radiocarpal arthritis, especially with neutral ulnar variance.

Question 64

Topic: Wrist & Carpus

A 65-year-old female undergoes volar locking plate fixation for a displaced distal radius fracture. Six months postoperatively, she presents with a sudden inability to actively flex the interphalangeal joint of her thumb. What is the most likely cause?

. Extensor pollicis longus rupture
. Flexor pollicis longus rupture
. Anterior interosseous nerve palsy
. Trigger thumb
. Flexor digitorum profundus rupture

Correct Answer & Explanation

. Flexor pollicis longus rupture

Explanation

Flexor pollicis longus (FPL) tendon rupture is a well-documented complication of volar plating. It is most often caused by attrition from plate prominence over the watershed line of the distal radius.

Question 65

Topic: Wrist & Carpus

In the anatomic evaluation and treatment of distal radius fractures, what is the normal radiographic volar tilt of the distal articular surface of the radius on a lateral radiograph?

. 0 degrees
. 5 degrees
. 11 degrees
. 22 degrees
. 30 degrees

Correct Answer & Explanation

. 11 degrees

Explanation

The normal anatomic volar tilt of the distal radius is approximately 11 to 12 degrees. Restoration of volar tilt is important to re-establish normal load transmission across the radiocarpal joint.

Question 66

Topic: Wrist & Carpus

A patient undergoing open reduction and internal fixation of a distal radius fracture with a volar locking plate develops an inability to flex the interphalangeal joint of the thumb 6 months postoperatively. Which of the following technical errors during the initial surgery is the most likely cause?

. Placement of the plate proximal to the watershed line
. Placement of the plate distal to the watershed line
. Penetration of screws into the distal radioulnar joint
. Over-penetration of dorsal screws
. Failure to repair the pronator quadratus completely

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 causes prominence of the hardware. This can lead to attritional rupture of the flexor pollicis longus (FPL) tendon over the plate edge.

Question 67

Topic: Wrist & Carpus

A 60-year-old male undergoes non-operative treatment for a non-displaced distal radius fracture. Eight weeks later, he presents with the sudden inability to actively extend his thumb interphalangeal joint. What is the most appropriate surgical treatment?

. Direct primary repair of the extensor pollicis longus tendon
. Extensor indicis proprius to extensor pollicis longus tendon transfer
. Flexor carpi radialis to extensor pollicis longus tendon transfer
. Thumb interphalangeal joint arthrodesis
. Palmaris longus autograft interposition

Correct Answer & Explanation

. Extensor indicis proprius to extensor pollicis longus tendon transfer

Explanation

Extensor pollicis longus (EPL) rupture after a distal radius fracture occurs due to ischemia or mechanical attrition at Lister's tubercle. Because the tendon ends are typically retracted and degenerate, an extensor indicis proprius (EIP) to EPL transfer is the gold standard treatment.

Question 68

Topic: Wrist & Carpus

During volar plating of a comminuted distal radius fracture, the surgeon suspects a screw may be protruding past the dorsal cortex into the extensor compartments. Which intraoperative fluoroscopic view is most sensitive to evaluate for this specific complication?

. Standard posteroanterior (PA) view
. Standard lateral view
. 11-degree elevated PA view
. Dorsal tangential (skyline) view
. 45-degree pronated oblique view

Correct Answer & Explanation

. Dorsal tangential (skyline) view

Explanation

The dorsal tangential (skyline) view is specifically designed to profile the dorsal cortex of the distal radius. It accurately assesses dorsal screw prominence, which can lead to extensor tendon irritation or rupture.

Question 69

Topic: Wrist & Carpus

A 55-year-old male treated non-operatively in a cast for a nondisplaced distal radius fracture presents 8 weeks post-injury with a sudden inability to actively extend his thumb interphalangeal joint. The fracture is radiographically healed. What is the most appropriate definitive surgical management?

. Primary end-to-end repair of the ruptured tendon
. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Palmaris longus interposition grafting of the tendon gap
. Flexor digitorum superficialis (FDS) 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) tendon transfer

Explanation

Extensor pollicis longus (EPL) ruptures following distal radius fractures usually result from ischemia and attrition within the tight third dorsal compartment. Because the tendon ends are typically degenerated and retracted, primary repair is rarely feasible, making an EIP to EPL tendon transfer the treatment of choice.

Question 70

Topic: Wrist & Carpus

Six weeks after open reduction and internal fixation of a distal radius fracture with a volar locking plate, a patient suddenly loses the ability to actively extend the interphalangeal joint of the thumb. Which technical error most likely caused this complication?

. Over-penetration of a dorsal cortical screw
. Failure to repair the pronator quadratus
. Plate placement distal to the watershed line
. Iatrogenic injury to the radial sensory nerve
. Excessive volar tilt correction

Correct Answer & Explanation

. Over-penetration of a dorsal cortical screw

Explanation

Extensor pollicis longus (EPL) rupture is a known complication of volar plating of the distal radius. It is most commonly caused by over-penetration of dorsal cortical screws, leading to mechanical attrition of the tendon in the third extensor compartment.

Question 71

Topic: Wrist & Carpus
A 65-year-old female presents with severe pain at the base of her thumb. Radiographs show Eaton-Littler Stage III trapeziometacarpal arthritis with significant subluxation and a 40-degree hyperextension deformity of the metacarpophalangeal (MCP) joint. In addition to a trapeziectomy and LRTI, what additional procedure must be performed?
. Thumb CMC arthrodesis
. Thumb MCP joint arthrodesis or volar capsulodesis
. Excision of the scaphoid
. Distal radius osteotomy
. Transfer of the EIP to the EPL

Correct Answer & Explanation

. Thumb MCP joint arthrodesis or volar capsulodesis

Explanation

In thumb CMC arthritis with an associated MCP joint hyperextension deformity of greater than 30 degrees, the MCP joint must be addressed to prevent recurrent CMC subluxation and weakness. This is typically managed with a volar capsulodesis, EPB transfer, or MCP joint arthrodesis.

Question 72

Topic: Wrist & Carpus

A 70-year-old patient with a history of diabetes and smoking undergoes a reverse radial forearm flap for coverage of an exposed distal radius fracture plate. On the first postoperative day, the flap appears dusky, swollen, and has sluggish capillary refill, despite adequate arterial Doppler signals. What is the most likely immediate complication, and what is the appropriate initial management?

. Arterial occlusion; urgent re-exploration for vascular repair.
. Infection; immediate broad-spectrum antibiotics and wound debridement.
. Venous congestion; elevate the extremity, release tight sutures, and consider leeches.
. Hematoma formation; surgical evacuation and placement of a drain.
. Partial flap necrosis; conservative management with dressing changes.

Correct Answer & Explanation

. Venous congestion; elevate the extremity, release tight sutures, and consider leeches.

Explanation

Correct Answer: CThe clinical presentation of a dusky, swollen flap with sluggish capillary refill, despite adequate arterial Doppler signals, is highly indicative ofvenous congestion. This is a common complication, especially in patients with comorbidities like diabetes and smoking, which can affect microvascular health. The initial management for venous congestion includes elevating the extremity to promote venous outflow, releasing any tight sutures or dressings that might be causing external compression, and considering adjunctive measures like medicinal leeches or heparin paste to improve venous drainage.Option A is incorrect; arterial occlusion would typically present with a pale, cold, non-blanching flap with absent arterial Doppler signals, which contradicts the presence of adequate arterial signals.Option B is incorrect; while infection is a risk, the immediate presentation points more towards a vascular issue. Infection typically manifests later with signs of inflammation (redness, warmth, purulence).Option D is incorrect; hematoma formation can cause swelling and compromise flap viability, but the dusky appearance and sluggish capillary refill are more specific to venous congestion. While a hematoma could contribute, venous congestion is the more direct diagnosis based on the description.Option E is incorrect; partial flap necrosis is an outcome of prolonged vascular compromise (often venous congestion), not the immediate complication itself. The goal is to manage the congestion to prevent necrosis.

Question 73

Topic: Wrist & Carpus
A 35-year-old male sustains a distal radius fracture. Radiographs show an extra-articular fracture of the distal radius with an associated ulnar styloid fracture. According to the Frykman classification system, what type of fracture does this represent?
. Frykman Type I
. Frykman Type II
. Frykman Type III
. Frykman Type IV
. Frykman Type V

Correct Answer & Explanation

. Frykman Type II

Explanation

The Frykman classification system categorizes distal radius fractures based on articular involvement and the presence of an ulnar styloid fracture: Type I: Extra-articular, no ulnar styloid fracture. Type II: Extra-articular, with ulnar styloid fracture. Type III: Intra-articular (radiocarpal joint only), no ulnar styloid fracture. Type IV: Intra-articular (radiocarpal joint only), with ulnar styloid fracture. Type V: Intra-articular (radiocarpal and distal radioulnar joint), no ulnar styloid fracture. Type VI: Intra-articular (radiocarpal and distal radioulnar joint), with ulnar styloid fracture. Therefore, an extra-articular distal radius fracture with an associated ulnar styloid fracture is classified as Frykman Type II.

Question 74

Topic: Wrist & Carpus

A 25-year-old male sustains a Galeazzi fracture-dislocation. After anatomic rigid fixation of the radius, the distal radioulnar joint (DRUJ) remains unstable in neutral but reduces and is stable in full supination. What is the most appropriate next step in management?

. Pinning of the DRUJ with two smooth K-wires in neutral rotation
. Open reduction and ligamentous repair of the triangular fibrocartilage complex (TFCC)
. Immobilization of the forearm in a long-arm cast or splint in supination for 4-6 weeks
. Resection of the distal ulna (Darrach procedure)
. Placement of a dynamic external fixator

Correct Answer & Explanation

. Immobilization of the forearm in a long-arm cast or splint in supination for 4-6 weeks

Explanation

If the DRUJ is unstable in neutral but stable in supination following anatomic radius fixation, nonoperative management with supination splinting or casting for 4-6 weeks is indicated. Pinning or TFCC repair is generally reserved for cases where the DRUJ remains unstable even in full supination.

Question 75

Topic: Wrist & Carpus

A 29-year-old man sustains a Galeazzi fracture-dislocation. Following rigid plate fixation of the radial diaphysis, the distal radioulnar joint (DRUJ) remains persistently subluxated despite supination. Which of the following structures is most commonly interposed, blocking anatomic reduction of the DRUJ?

. Extensor Carpi Ulnaris (ECU) tendon
. Flexor Carpi Ulnaris (FCU) tendon
. Triangular Fibrocartilage Complex (TFCC) central disk
. Median nerve
. Pronator quadratus muscle belly

Correct Answer & Explanation

. Extensor Carpi Ulnaris (ECU) tendon

Explanation

In a Galeazzi fracture, if the DRUJ is irreducible after anatomic fixation of the radius, soft tissue interposition is likely. The Extensor Carpi Ulnaris (ECU) tendon is the most commonly interposed structure.

Question 76

Topic: Wrist & Carpus

A 28-year-old male undergoes ORIF for a highly comminuted both-bone forearm fracture. Six months postoperatively, radiographs demonstrate bridging callus and union, but he has a 40-degree deficit in supination. The radial bow was reconstructed with 10% less magnitude than the contralateral side. What is the most likely cause of his restricted supination?

. Loss of radial bow magnitude
. Proximal migration of the radius
. Undiagnosed DRUJ instability
. Contracture of the pronator quadratus
. Heterotopic ossification of the interosseous membrane

Correct Answer & Explanation

. Loss of radial bow magnitude

Explanation

Restoration of the radial bow is critical for maintaining normal forearm rotation. A loss of the magnitude of the radial bow (even minor alterations) or shifting of the apex of the bow directly correlates with a mechanical loss of forearm rotation, particularly pronation and supination.

Question 77

Topic: Wrist & Carpus



A 45-year-old mechanic sustains a Galeazzi fracture-dislocation. Following rigid plate fixation of the radial shaft, the distal radioulnar joint (DRUJ) is noted to be grossly unstable in supination. What is the recommended acute management for the DRUJ?

. Perform a Darrach procedure
. Pin the DRUJ in pronation with K-wires
. Repair the triangular fibrocartilage complex (TFCC) via an open approach
. Cast immobilization in full pronation
. Pin the DRUJ in supination or immobilize in a long-arm cast in supination

Correct Answer & Explanation

. Pin the DRUJ in supination or immobilize in a long-arm cast in supination

Explanation

In a Galeazzi fracture, if the DRUJ remains unstable after anatomic radius fixation, the forearm should be assessed in supination. If stable in supination, immobilization in a long-arm cast in supination is indicated; if still unstable, percutaneous pinning of the DRUJ in supination is recommended.

Question 78

Topic: Wrist & Carpus

A distal radius fracture is stabilized with a volar locking plate. Compared to conventional non-locking plates, the stability of this locked construct relies primarily on which biomechanical mechanism?

. Friction between the plate and the underlying bone surface
. Thread engagement in the far cortex only
. Fixed-angle coupling between the screw head and the plate
. Dynamic interfragmentary compression
. Plastic deformation of the plate

Correct Answer & Explanation

. Fixed-angle coupling between the screw head and the plate

Explanation

Locked plates function as single-beam constructs where stability depends on the fixed-angle threaded coupling between the screw head and the plate hole. Unlike conventional plates, they do not rely on friction between the plate and the bone.

Question 79

Topic: Wrist & Carpus

A surgeon is repairing a Galeazzi fracture in a 32-year-old male. Following anatomic open reduction and rigid internal fixation of the radial shaft, the distal radioulnar joint (DRUJ) remains grossly unstable. What is the most appropriate next step in management?

. Percutaneous pinning of the DRUJ with the forearm positioned in maximal supination
. Percutaneous pinning of the DRUJ with the forearm positioned in maximal pronation
. Immediate open repair of the triangular fibrocartilage complex (TFCC) through a dorsal approach
. Resection of the distal ulna (Darrach procedure)
. Application of a hinged elbow external fixator

Correct Answer & Explanation

. Percutaneous pinning of the DRUJ with the forearm positioned in maximal supination

Explanation

If the DRUJ remains unstable after anatomic fixation of the radius in a Galeazzi fracture, the joint should be reduced and stabilized with K-wires in maximal supination, which is the most stable position for the DRUJ.

Question 80

Topic: Wrist & Carpus

A 55-year-old female presents with sudden inability to flex the interphalangeal joint of her thumb. Seven months prior, she underwent volar locking plate fixation for a distal radius fracture. Radiographs reveal the volar plate is positioned distal to the watershed line. Which tendon is most likely injured?

. Flexor carpi radialis (FCR)
. Flexor digitorum superficialis (FDS) to the index finger
. Flexor digitorum profundus (FDP) to the index finger
. Flexor pollicis longus (FPL)
. Abductor pollicis longus (APL)

Correct Answer & Explanation

. Flexor pollicis longus (FPL)

Explanation

Volar plates placed distal to the watershed line of the distal radius are a well-documented cause of flexor tendon irritation and rupture. The flexor pollicis longus (FPL) tendon is most commonly affected due to its immediate proximity to the hardware.

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