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Wrist & Carpus MCQs

Practice Set 5 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 81

Topic: Wrist & Carpus
According to the Mayfield classification of progressive perilunate instability, a Stage III injury is defined by the disruption of which of the following specific ligamentous structures?
. Scapholunate interosseous ligament
. Dorsal radiocarpal ligament
. Lunotriquetral interosseous ligament
. Volar radioscaphocapitate ligament
. Ulnocarpal complex

Correct Answer & Explanation

. Scapholunate interosseous ligament

Explanation

The Mayfield sequence describes the typical progression of perilunate instability: Stage I is scapholunate failure, Stage II involves capitate dislocation, Stage III is lunotriquetral disruption, and Stage IV is complete lunate dislocation.

Question 82

Topic: Wrist & Carpus

A 60-year-old female presents with a sudden inability to actively extend her thumb interphalangeal joint 6 weeks after a non-operatively treated, undisplaced distal radius fracture. What is the primary pathomechanism of this specific complication?

. Iatrogenic nerve injury from an improperly molded cast
. Anterior interosseous nerve palsy secondary to hematoma
. Mechanical attrition and localized hypovascularity of the extensor pollicis longus tendon
. Entrapment of the extensor pollicis brevis tendon within the fracture site
. Failure of the sagittal band at the metacarpophalangeal joint

Correct Answer & Explanation

. Mechanical attrition and localized hypovascularity of the extensor pollicis longus tendon

Explanation

Spontaneous rupture of the extensor pollicis longus (EPL) tendon is a known complication of minimally displaced distal radius fractures. It is caused by mechanical attrition of the tendon against the fracture callus at Lister's tubercle, compounded by a watershed area of hypovascularity in the tendon.

Question 83

Topic: Wrist & Carpus

A 42-year-old male presents to the emergency department after falling onto his outstretched left hand with his forearm in pronation. He complains of severe pain and deformity in his distal forearm. Physical examination reveals a shortened, radially deviated forearm with a prominent ulnar head dorsally. Initial radiographs are shown below. Which of the following is the most appropriate initial management step?

. Closed reduction and long arm cast immobilization in pronation.
. Immediate open reduction and internal fixation (ORIF) of the radial shaft with assessment of DRUJ stability.
. Application of a sugar tong splint and referral for delayed surgical consultation.
. Percutaneous pinning of the distal radioulnar joint (DRUJ) followed by a short arm cast.
. Attempted closed reduction of the DRUJ followed by a long arm cast in supination, without addressing the radial fracture.

Correct Answer & Explanation

. Immediate open reduction and internal fixation (ORIF) of the radial shaft with assessment of DRUJ stability.

Explanation

Correct Answer: BThe patient's presentation (fall on outstretched hand in pronation, shortened/radially deviated forearm, prominent dorsal ulnar head) and the described radiographs are classic for a Galeazzi fracture-dislocation (fracture of the distal third of the radial diaphysis with associated distal radioulnar joint (DRUJ) disruption). In adults, Galeazzi fractures are inherently unstable due to the loss of radial support and muscle forces (brachioradialis, pronator quadratus) acting on the fragments, as well as the associated DRUJ injury. Non-operative management in adults is associated with unacceptably high rates of malunion, nonunion, and persistent DRUJ instability (often 50-100%). Therefore, the definitive management for an adult Galeazzi fracture is immediate open reduction and internal fixation (ORIF) of the radial shaft to restore anatomical length, rotation, and alignment. This is followed by a careful assessment of DRUJ stability, which often reduces indirectly once radial anatomy is restored. If the DRUJ remains unstable, direct stabilization (e.g., temporary K-wire fixation) is performed.Option A is incorrect because closed reduction and casting are rarely successful in adults due to the inherent instability and high risk of malunion/redislocation. Option C is incorrect as delayed surgical consultation for an adult Galeazzi fracture is inappropriate; definitive fixation is required. Option D is incorrect because pinning the DRUJ without addressing the radial shaft fracture will not provide stability or restore radial length. Option E is incorrect as it prioritizes DRUJ reduction over the primary radial fracture, and attempting to reduce the DRUJ without stabilizing the radius is futile and will not lead to a stable construct.

Question 84

Topic: Wrist & Carpus

Following successful open reduction and internal fixation of the radial shaft in an adult Galeazzi fracture, the surgeon performs an intraoperative assessment of the distal radioulnar joint (DRUJ). Despite anatomical reduction and stable plating of the radius, the DRUJ remains unstable with excessive dorsal translation of the ulna during forearm rotation. What is the most appropriate next step?

. Accept the DRUJ instability, as it will resolve with early rehabilitation.
. Perform an ulnar shortening osteotomy to decompress the DRUJ.
. Explore the DRUJ for soft tissue interposition (e.g., pronator quadratus, ECU tendon) and stabilize with temporary K-wires in supination.
. Apply a short arm cast and refer for a second-stage DRUJ reconstruction.
. Perform a Darrach procedure (ulnar head excision) immediately.

Correct Answer & Explanation

. Explore the DRUJ for soft tissue interposition (e.g., pronator quadratus, ECU tendon) and stabilize with temporary K-wires in supination.

Explanation

Correct Answer: CThe primary goal of Galeazzi fracture management is to restore anatomical radial length, rotation, and alignment, which often indirectly reduces and stabilizes the DRUJ. However, if the DRUJ remains unstable after stable radial fixation, direct intervention is necessary. The most appropriate next step is to explore the DRUJ for any incarcerated soft tissues (such as the pronator quadratus muscle, extensor carpi ulnaris (ECU) tendon, or capsule) that might be preventing full reduction. After ensuring no interposition, the DRUJ should be stabilized with temporary K-wires. For dorsal instability, the forearm is typically placed in full supination to tighten the volar radioulnar ligaments, and K-wires are inserted from the dorsal ulna into the radius. These pins are usually left in place for 4-6 weeks to allow capsuloligamentous healing.Option A is incorrect because persistent DRUJ instability after radial fixation will lead to chronic pain, limited forearm rotation, and poor functional outcomes. Option B (ulnar shortening osteotomy) and Option E (Darrach procedure) are salvage procedures for chronic DRUJ pathology or malunion, not acute management for persistent instability after primary fixation. Option D is incorrect as a second-stage reconstruction is not the initial approach for acute instability; it should be addressed during the primary surgery.

Question 85

Topic: Wrist & Carpus

A 9-year-old child sustains a fall and presents with a fracture of the distal radial diaphysis and associated dorsal dislocation of the distal ulna. Radiographs confirm a Galeazzi-type injury. Compared to the management of an adult with the same injury, what is the most common and often successful initial management approach for this child?

. Immediate open reduction and internal fixation (ORIF) of the radial shaft.
. External fixation of the forearm with dynamic traction.
. Closed reduction of the radial fracture and DRUJ, followed by long arm cast immobilization in supination.
. Ulnar head resection to prevent future impingement.
. Percutaneous pinning of the radial shaft and DRUJ.

Correct Answer & Explanation

. Closed reduction of the radial fracture and DRUJ, followed by long arm cast immobilization in supination.

Explanation

Correct Answer: CThe management of Galeazzi-type injuries differs significantly between children and adults. In children, due to their greater remodeling potential, thicker periosteum, and more resilient ligaments, closed reduction of both the radial shaft fracture and the distal radioulnar joint (DRUJ) is often successful. Once reduced, the forearm is typically immobilized in a long arm cast with the forearm in full supination (or neutral position) to help maintain reduction of the DRUJ by tightening the volar radioulnar ligaments. ORIF (Option A) is generally reserved for unstable or irreducible cases in children. External fixation (Option B) is rarely the primary definitive treatment for this injury in children. Ulnar head resection (Option D) is a salvage procedure for chronic DRUJ issues in adults and is never indicated acutely in children. Percutaneous pinning (Option E) might be used in some unstable pediatric cases, but closed reduction and casting is the initial attempt if possible.

Question 86

Topic: Wrist & Carpus

A 65-year-old patient presents with chronic, painful distal radioulnar joint (DRUJ) arthritis and severe positive ulnar variance following a malunited Galeazzi fracture treated 2 years prior. She has exhausted non-operative treatments including injections and therapy. Her radial shaft fracture is healed but shortened. Which of the following salvage procedures would be most appropriate to address her DRUJ pathology and improve forearm rotation?

. Scaphoidectomy and four-corner fusion.
. Proximal row carpectomy.
. Sauve-Kapandji procedure.
. Radial shortening osteotomy.
. Wrist arthrodesis.

Correct Answer & Explanation

. Sauve-Kapandji procedure.

Explanation

Correct Answer: CFor chronic, painful DRUJ arthritis and severe positive ulnar variance resulting from a malunited Galeazzi fracture, salvage procedures are often necessary. The Sauve-Kapandji procedure is a well-established option. It involves arthrodesis (fusion) of the distal radioulnar joint combined with a pseudoarthrosis (creation of a false joint) of the ulna proximal to the fusion. This allows for forearm rotation while maintaining the distal ulna for cosmetic appearance and some stability. Another common salvage procedure is the Darrach procedure (excision of the distal ulna or ulnar head), which also aims to relieve impingement and restore rotation.Option A (Scaphoidectomy and four-corner fusion) and Option B (Proximal row carpectomy) are procedures for midcarpal or radiocarpal arthritis, not primarily for DRUJ pathology. Option D (Radial shortening osteotomy) would worsen the positive ulnar variance; an ulnar shortening osteotomy might be considered if the radial fracture was anatomically healed and the primary issue was ulnar length, but not for irreducible DRUJ arthritis. Option E (Wrist arthrodesis) fuses the entire wrist, sacrificing all wrist motion, which is a more extensive procedure typically reserved for diffuse pancarpal arthritis or severe instability not amenable to other options, and it doesn't specifically address DRUJ rotation.

Question 87

Topic: Wrist & Carpus

After successful open reduction and internal fixation of a Galeazzi fracture and temporary K-wire stabilization of a persistently unstable distal radioulnar joint (DRUJ), what is a key principle of early postoperative rehabilitation?

. Immediate active forearm pronation and supination exercises to prevent stiffness.
. Strict immobilization of the forearm in a long arm cast until K-wires are removed (typically 4-6 weeks).
. Early passive range of motion of the wrist and elbow, avoiding any forearm rotation.
. Aggressive strengthening of the wrist flexors and extensors starting on postoperative day 1.
. Removal of the cast after 2 weeks and transition to a removable brace for full activity.

Correct Answer & Explanation

. Strict immobilization of the forearm in a long arm cast until K-wires are removed (typically 4-6 weeks).

Explanation

Correct Answer: BWhen the DRUJ has been stabilized with temporary K-wires following Galeazzi fracture fixation, the primary goal of early postoperative rehabilitation is to protect the healing capsuloligamentous structures of the DRUJ. This necessitates strict immobilization of the forearm, typically in a long arm cast or splint, in the position of DRUJ stability (e.g., supination for dorsal instability). The K-wires are usually maintained for 4-6 weeks to allow sufficient time for soft tissue healing. Premature or aggressive forearm rotation (Option A) would risk disrupting the healing DRUJ ligaments, leading to recurrent instability or pin complications. After K-wire removal and clinical assessment of DRUJ stability, a gradual and protected range of motion program for forearm rotation can be initiated.Option C is partially correct regarding wrist and elbow motion, but strict immobilization of the forearm is paramount. Option D (aggressive strengthening) is too early and risks disrupting fixation and healing. Option E (early cast removal and full activity) is far too aggressive and would almost certainly lead to failure of DRUJ stabilization and potential radial malunion.

Question 88

Topic: Wrist & Carpus

To appropriately evaluate reduction of a distal radius fracture, the surgeon must understand normal radiographic parameters. Which of the following values most accurately represents the normal native anatomy of the distal radius?

. Radial inclination 22 degrees, Volar tilt 11 degrees, Radial height 12 mm
. Radial inclination 11 degrees, Volar tilt 22 degrees, Radial height 5 mm
. Radial inclination 15 degrees, Volar tilt 5 degrees, Radial height 22 mm
. Radial inclination 22 degrees, Dorsal tilt 11 degrees, Radial height 12 mm
. Radial inclination 30 degrees, Volar tilt 0 degrees, Radial height 15 mm

Correct Answer & Explanation

. Radial inclination 22 degrees, Volar tilt 11 degrees, Radial height 12 mm

Explanation

The standard radiographic parameters of the normal distal radius are approximately 22 degrees of radial inclination, 11 degrees of volar tilt, and 11 to 12 mm of radial height.

Question 89

Topic: Wrist & Carpus

A 35-year-old man undergoes volar plating of a distal radius fracture. Three months postoperatively, he develops sudden inability to actively flex the interphalangeal joint of his thumb. Which technical error most likely contributed to this complication?

. Plate placement distal to the watershed line
. Use of excessively long dorsal locking screws
. Failure to repair the pronator quadratus completely
. Inadequate reduction of the volar tilt
. Over-penetration of the drill bit into the DRUJ

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a known complication of volar plating. It occurs due to tendon attrition over a prominent plate placed too distally (beyond the watershed line) on the radius.

Question 90

Topic: Wrist & Carpus

A 24-year-old falls onto an outstretched hand and sustains a Galeazzi fracture. Following open reduction and internal fixation of the radius, the distal radioulnar joint (DRUJ) remains unstable in supination. What is the most appropriate next step in management?

. Cast immobilization in maximal pronation
. Open reduction of the DRUJ with TFCC repair
. Transfixion pinning of the DRUJ in neutral or supination
. Darrach procedure
. Resection of the ulnar styloid

Correct Answer & Explanation

. Transfixion pinning of the DRUJ in neutral or supination

Explanation

If the DRUJ remains unstable after anatomic fixation of the radius in a Galeazzi fracture, it should be reduced and pinned using K-wires in the position of maximum stability (usually supination).

Question 91

Topic: Wrist & Carpus

A 55-year-old woman sustains an extra-articular distal radius fracture treated with closed reduction and casting. Four weeks later, she reports a sudden pop and inability to actively extend her thumb interphalangeal joint. What is the most common management for this complication?

. Primary end-to-end repair of the ruptured tendon
. Extensor indicis proprius to extensor pollicis longus transfer
. Palmaris longus interposition graft
. Thumb interphalangeal joint arthrodesis
. Flexor digitorum superficialis transfer

Correct Answer & Explanation

. Extensor indicis proprius to extensor pollicis longus transfer

Explanation

Extensor pollicis longus (EPL) rupture at Lister's tubercle is a known complication of nondisplaced or minimally displaced distal radius fractures. Treatment of choice is an EIP to EPL tendon transfer because the ruptured ends are typically retracted and attenuated.

Question 92

Topic: Wrist & Carpus

A 25-year-old snowboarder falls and sustains a severely displaced intra-articular distal radius fracture. Which radiographic parameter is most predictive of developing symptomatic post-traumatic radiocarpal osteoarthrosis?

. Loss of radial inclination greater than 10 degrees
. Volar tilt of 5 degrees dorsal
. Intra-articular step-off greater than 2 mm
. Radial shortening of 3 mm
. Ulnar variance of +1 mm

Correct Answer & Explanation

. Intra-articular step-off greater than 2 mm

Explanation

The most critical radiographic factor correlating with the development of post-traumatic arthritis after a distal radius fracture is an intra-articular step-off of greater than 2 mm. Anatomic reduction of the articular surface is a primary goal of operative intervention.

Question 93

Topic: Wrist & Carpus

A 30-year-old male sustains a Galeazzi fracture. After rigid open reduction and internal fixation of the radius, the distal radioulnar joint (DRUJ) remains unstable in pronation but is stable when the forearm is placed in full supination. What is the most appropriate intraoperative management of the DRUJ?

. Immobilize the forearm in a long arm cast in pronation
. Immobilize or percutaneously pin the DRUJ in supination
. Perform an open repair of the volar radioulnar ligament
. Perform a prophylactic Darrach procedure
. Perform an open reduction of the DRUJ through a dorsal approach

Correct Answer & Explanation

. Immobilize or percutaneously pin the DRUJ in supination

Explanation

If the DRUJ is reducible and stable in supination after radius fixation in a Galeazzi fracture, it should be immobilized or pinned in supination for 4 to 6 weeks. Pinning in the position of stability ensures joint congruence while the triangular fibrocartilage complex (TFCC) heals.

Question 94

Topic: Wrist & Carpus

A 32-year-old male sustains a distal third radial shaft fracture with an associated distal radioulnar joint (DRUJ) dislocation (Galeazzi fracture). Open reduction and internal fixation of the radius is performed. Intraoperatively, the DRUJ is found to be highly unstable in pronation but reduces well in supination. What is the most appropriate next step in management of the DRUJ?

. Pinning of the DRUJ in pronation
. Open repair of the triangular fibrocartilage complex (TFCC)
. Functional bracing without further fixation
. Closed reduction and pinning of the DRUJ in supination
. Primary resection of the distal ulna

Correct Answer & Explanation

. Closed reduction and pinning of the DRUJ in supination

Explanation

Galeazzi fractures frequently involve DRUJ instability that persists after radial fixation. The DRUJ should be reduced and pinned in supination, which is the position of maximum anatomic stability for this joint.

Question 95

Topic: Wrist & Carpus

When evaluating a post-reduction radiograph of an adult distal radius fracture, which of the following represents the widely accepted normal radiographic parameters for radial inclination, radial height, and volar tilt, respectively?

. 10 degrees, 5 mm, 0 degrees
. 22 degrees, 11 mm, 11 degrees
. 15 degrees, 22 mm, 5 degrees
. 30 degrees, 15 mm, 20 degrees
. 5 degrees, 11 mm, 22 degrees

Correct Answer & Explanation

. 22 degrees, 11 mm, 11 degrees

Explanation

Normal radiographic parameters of the distal radius include a radial inclination of 22 degrees, a radial height of 11-12 mm, and a volar tilt of 11 degrees. Restoration of these metrics is crucial for optimizing functional outcomes.

Question 96

Topic: Wrist & Carpus

During volar locking plate fixation of a distal radius fracture, screws placed into the distal fragments can protrude dorsally if they are too long. Which anatomical landmark serves as a critical pulley for the extensor pollicis longus (EPL) tendon, placing it at high risk of attritional rupture from prominent dorsal hardware?

. Radial styloid
. Sigmoid notch
. Lister's tubercle
. Ulnar styloid
. Volar rim

Correct Answer & Explanation

. Lister's tubercle

Explanation

Lister's tubercle acts as a bony pulley for the extensor pollicis longus (EPL) tendon, which resides in the third extensor compartment. Dorsally prominent screws near this landmark frequently cause attritional rupture of the EPL.

Question 97

Topic: Wrist & Carpus

A 55-year-old female presents with an inability to flex her thumb interphalangeal joint 6 months after open reduction and internal fixation of a distal radius fracture with a volar locking plate. What surgical technical error most likely led to this complication?

. Placement of screws into the radiocarpal joint
. Plate placement distal to the watershed line
. Over-penetration of dorsal cortical screws
. Failure to repair the pronator quadratus
. Excessive radial inclination correction

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a known complication of volar plating for distal radius fractures. It most commonly occurs due to prominent hardware placed distal to the watershed line, causing attritional wear of the tendon.

Question 98

Topic: Wrist & Carpus

A 10-year-old girl with multiple hereditary exostoses presents for routine follow-up. Which of the following is the most classic forearm deformity associated with this condition?

. Relative overgrowth of the ulna leading to radial deviation
. Ulnar shortening with secondary radial bowing and ulnar deviation of the carpus
. Radial shortening with a positive ulnar variance
. Dorsal subluxation of the distal radioulnar joint (DRUJ) isolated without bowing
. Congenital radioulnar synostosis

Correct Answer & Explanation

. Ulnar shortening with secondary radial bowing and ulnar deviation of the carpus

Explanation

The classic forearm deformity in multiple hereditary exostoses (MHE) involves disproportionate growth restriction of the distal ulna. This leads to relative ulnar shortening, secondary bowing of the radius, ulnar deviation of the carpus, and possible radial head dislocation.

Question 99

Topic: Wrist & Carpus

A 62-year-old female underwent volar plating for a distal radius fracture 8 weeks ago. She now complains of a sudden inability to flex the interphalangeal joint of her thumb. Which of the following is the most likely cause of this complication?

. Prominent screw tips penetrating the dorsal cortex
. Plate placement proximal to the watershed line
. Plate placement distal to the watershed line
. Injury to the anterior interosseous nerve during approach
. Nonunion of the distal radius

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Placing a volar plate distal to the watershed line of the distal radius creates a prominence that can cause attritional rupture of the flexor pollicis longus (FPL) tendon. The FPL is particularly vulnerable due to its close anatomical relationship to the volar cortex.

Question 100

Topic: Wrist & Carpus

Which of the following radiographic parameters is the most critical to restore during the operative fixation of an intra-articular distal radius fracture to prevent radiocarpal arthrosis?

. Radial inclination
. Radial height
. Volar tilt
. Intra-articular step-off less than 2 mm
. Ulnar variance

Correct Answer & Explanation

. Intra-articular step-off less than 2 mm

Explanation

While restoring extra-articular alignment is important for overall mechanics, correcting an intra-articular step-off or gap to less than 2 mm is the most critical factor for minimizing the risk of post-traumatic radiocarpal arthrosis.

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