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7. Hand and Wrist MCQs

Practice Set 34 of 266

This practice set contains high-yield board review questions covering key concepts in 7. Hand and Wrist. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 661

Topic: 7. Hand and Wrist

What is the primary mechanism of injury for a typical Galeazzi fracture-dislocation?

. Direct blow to the ulnar side of the forearm
. Fall onto an outstretched hand with the forearm in pronation
. Fall onto an outstretched hand with the forearm in supination
. Hyperflexion injury of the wrist
. Rotational force applied to a flexed elbow

Correct Answer & Explanation

. Fall onto an outstretched hand with the forearm in pronation

Explanation

Correct Answer: BThe typical mechanism for a Galeazzi fracture is a fall onto an outstretched hand with the forearm in pronation. This axial load combined with pronation results in an oblique or transverse fracture of the distal radius and often disrupts the DRUJ, as pronation tightens the interosseous membrane, transferring forces to the DRUJ.

Question 662

Topic: Wrist & Carpus

In an adult patient with a confirmed Galeazzi fracture-dislocation, what is the generally accepted definitive management strategy?

. Closed reduction and long arm casting
. Percutaneous pinning of the radius and DRUJ
. Open reduction and internal fixation (ORIF) of the radial shaft with assessment of DRUJ stability
. External fixation of the forearm with dynamic traction
. Ulnar head resection

Correct Answer & Explanation

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

Explanation

Correct Answer: CGaleazzi fractures in adults are inherently unstable due to the loss of stability provided by the intact radial shaft and disruption of the DRUJ. Non-operative management leads to high rates of malunion and persistent DRUJ instability. Therefore, open reduction and internal fixation (ORIF) of the radial shaft is the standard of care, aiming to restore radial length, rotation, and alignment, followed by careful assessment and, if necessary, stabilization of the DRUJ.

Question 663

Topic: 7. Hand and Wrist

Which of the following radiographic findings is crucial for diagnosing a Galeazzi fracture and assessing DRUJ involvement, beyond the obvious radial shaft fracture?

. Radial head subluxation
. Positive ulnar variance
. Widening of the DRUJ space on an AP view and/or dorsal displacement of the ulna on a lateral view
. Scapholunate dissociation
. Presence of an os centrale

Correct Answer & Explanation

. Widening of the DRUJ space on an AP view and/or dorsal displacement of the ulna on a lateral view

Explanation

Correct Answer: CWhile a radial shaft fracture is central to the diagnosis, the key to recognizing a Galeazzi injury is the associated DRUJ disruption. Radiographically, this often manifests as widening of the DRUJ space on the AP view and/or dorsal (less commonly volar) displacement of the ulna relative to the radius on the lateral view. Comparing to the contralateral wrist can be helpful. Radial head subluxation is associated with Monteggia fractures. Positive ulnar variance can be a normal variant or occur with certain wrist pathologies but is not diagnostic for Galeazzi. Scapholunate dissociation relates to carpal instability.

Question 664

Topic: Wrist & Carpus

During open reduction and internal fixation of a Galeazzi fracture, after stable fixation of the radial shaft is achieved, the DRUJ remains unstable with forearm rotation. What is the most appropriate next step in managing the DRUJ?

. Accept the instability as it will improve with rehabilitation
. Immediately proceed with an ulnar head resection
. Assess for interposition of soft tissues (e.g., pronator quadratus, extensor carpi ulnaris tendon) and consider temporary K-wire fixation of the DRUJ
. Apply a sugar tong splint and defer DRUJ treatment
. Perform a Sauve-Kapandji procedure

Correct Answer & Explanation

. Assess for interposition of soft tissues (e.g., pronator quadratus, extensor carpi ulnaris tendon) and consider temporary K-wire fixation of the DRUJ

Explanation

Correct Answer: CIf, after anatomical reduction and stable fixation of the radial shaft, the DRUJ remains unstable, it is critical to address this. Common causes of persistent instability include interposition of soft tissues (e.g., pronator quadratus, ECU tendon) within the joint, or significant injury to the TFCC or capsule. The most appropriate immediate step is to ensure there are no incarcerated soft tissues preventing reduction and then to stabilize the DRUJ with temporary K-wire fixation, typically with the forearm in supination (or neutral if stable) for 4-6 weeks to allow capsuloligamentous healing. Ulnar head resection or Sauve-Kapandji are salvage procedures for chronic instability or malunion, not primary acute management.

Question 665

Topic: 7. Hand and Wrist

What is the recommended forearm position for temporary K-wire stabilization of the DRUJ following ORIF of a Galeazzi fracture, in cases where dorsal instability is present?

. Full pronation
. Neutral rotation
. Full supination
. Wrist flexion
. Wrist extension

Correct Answer & Explanation

. Full supination

Explanation

Correct Answer: CFor dorsal DRUJ instability, the forearm is typically immobilized in full supination. In this position, the dorsal DRUJ ligaments are taut, helping to maintain reduction of the ulnar head relative to the sigmoid notch of the radius. Conversely, volar instability (less common in Galeazzi) would require pronation. Pins are usually placed from the dorsal ulna into the radius, avoiding the extensor tendons.

Question 666

Topic: 7. Hand and Wrist

Which nerve is most at risk of injury during a volar approach (Henry approach) to the distal radius for Galeazzi fracture fixation?

. Ulnar nerve
. Median nerve
. Superficial radial nerve
. Posterior interosseous nerve (PIN)
. Anterior interosseous nerve (AIN)

Correct Answer & Explanation

. Anterior interosseous nerve (AIN)

Explanation

Correct Answer: EThe anterior interosseous nerve (AIN), a branch of the median nerve, is most vulnerable during a volar approach (Henry approach) to the distal radius. It courses on the interosseous membrane and innervates the flexor pollicis longus, pronator quadratus, and the radial half of the flexor digitorum profundus. Injury can occur during dissection, especially when mobilizing the pronator quadratus or stripping muscle from the interosseous membrane. The median nerve trunk itself is deeper but can be retracted. The PIN is associated with the dorsal approach (Thompson approach).

Question 667

Topic: 7. Hand and Wrist

What is the primary role of the interosseous membrane in forearm stability, particularly relevant in Galeazzi injuries?

. To provide attachment for wrist extensors
. To separate the anterior and posterior compartments
. To transmit axial loads between the radius and ulna and resist longitudinal displacement
. To house the neurovascular bundles
. To lubricate joint surfaces

Correct Answer & Explanation

. To transmit axial loads between the radius and ulna and resist longitudinal displacement

Explanation

Correct Answer: CThe interosseous membrane plays a critical role in forearm stability. Its oblique fibers primarily run from the radius distally and medially to the ulna proximally. This orientation allows it to transmit axial loads from the hand via the radius to the ulna, and also resist longitudinal displacement and provide stability against proximal migration of the radius relative to the ulna, especially during pronation. Its disruption, or altered tension due to radial shortening, significantly impacts DRUJ stability.

Question 668

Topic: Wrist & Carpus

Which specific muscles attach to the distal third of the radius and may be directly involved in the fracture displacement or complicate surgical exposure?

. Flexor carpi radialis and palmaris longus
. Brachioradialis and Pronator Quadratus
. Extensor digitorum communis and extensor carpi ulnaris
. Biceps brachii and supinator
. Triceps brachii and anconeus

Correct Answer & Explanation

. Brachioradialis and Pronator Quadratus

Explanation

Correct Answer: BThe Brachioradialis inserts into the lateral side of the distal radius and its pull can contribute to proximal displacement and shortening of the radial fracture fragment. The Pronator Quadratus originates from the distal ulna and inserts onto the distal radius, acting as a pronator and a key stabilizer of the DRUJ. Its muscle belly can be lacerated by the fracture or complicate exposure during a volar approach.

Question 669

Topic: Wrist & Carpus

A 28-year-old male undergoes ORIF for a Galeazzi fracture. After rigid anatomic fixation of the radius, the DRUJ remains unstable in both pronation and neutral rotation, but reduces congruently and is stable in full supination. What is the most appropriate next step in management?

. ORIF of the ulnar styloid using a tension band construct
. Transarticular radioulnar K-wire pinning in neutral rotation
. Immobilization in a long-arm splint or cast in full supination for 4-6 weeks
. Immediate open repair of the TFCC foveal avulsion
. Resection of the distal ulna (Darrach procedure)

Correct Answer & Explanation

. Immobilization in a long-arm splint or cast in full supination for 4-6 weeks

Explanation

If the DRUJ is reducible and stable in a specific position (typically full supination) following rigid fixation of the radius, the standard of care is to immobilize the forearm in that stable position for 4 to 6 weeks. Transarticular pinning or open TFCC repair is reserved for DRUJ instability that cannot be stabilized by positioning alone.

Question 670

Topic: 7. Hand and Wrist

In a patient presenting with a distal third radial shaft fracture, which of the following physical examination findings is the most reliable clinical indicator of a concomitant distal radioulnar joint (DRUJ) injury (Galeazzi fracture)?

. Weakness in independent thumb extension
. Prominence of the ulnar head with excessive ballotability
. Paresthesias isolated to the median nerve distribution
. Inability to actively flex the wrist against resistance
. Crepitus localized to the radiocapitellar joint

Correct Answer & Explanation

. Prominence of the ulnar head with excessive ballotability

Explanation

Clinical signs of DRUJ instability, defining a Galeazzi fracture, include dorsal or volar prominence of the ulnar head, increased ballotability (piano key sign), and localized pain or swelling precisely at the DRUJ.

Question 671

Topic: Wrist & Carpus

A 55-year-old female develops a delayed extensor pollicis longus (EPL) tendon rupture 6 weeks following a non-operatively managed, non-displaced distal radius fracture. What is the primary accepted etiology of this complication?

. Primary attrition against a prominent volar plate
. Vascular watershed ischemia near Lister tubercle due to hematoma and localized pressure
. Direct laceration by a sharp fracture spike at the time of injury
. Rheumatoid synovial infiltration secondary to post-traumatic arthritis
. Iatrogenic tendon injury during closed reduction maneuvering

Correct Answer & Explanation

. Vascular watershed ischemia near Lister tubercle due to hematoma and localized pressure

Explanation

Delayed EPL rupture following non-displaced distal radius fractures is primarily attributed to ischemia. The intact extensor retinaculum prevents hematoma expansion, increasing pressure on the EPL in its watershed vascular zone as it curves around Lister's tubercle.

Question 672

Topic: Wrist & Carpus

A 28-year-old male presents with a Galeazzi fracture-dislocation. Closed reduction of the distal radioulnar joint (DRUJ) is attempted but remains irreducible. Which anatomic structure is most commonly responsible for preventing reduction of the DRUJ in this setting?

. Extensor carpi ulnaris (ECU) tendon
. Flexor carpi ulnaris (FCU) tendon
. Extensor digiti minimi (EDM) tendon
. Pronator quadratus muscle
. Brachioradialis tendon

Correct Answer & Explanation

. Extensor carpi ulnaris (ECU) tendon

Explanation

The ECU tendon is the most common block to DRUJ reduction in Galeazzi fracture-dislocations. It can become incarcerated in the joint, necessitating open reduction.

Question 673

Topic: Wrist & Carpus

In a Galeazzi fracture, multiple muscle forces act on the distal radial fragment, contributing to displacement and DRUJ disruption. Which of the following muscles is the primary deforming force causing pronation and proximal migration of the distal radial fragment?

. Brachioradialis
. Pronator teres
. Pronator quadratus
. Flexor pollicis longus
. Abductor pollicis longus

Correct Answer & Explanation

. Pronator quadratus

Explanation

The pronator quadratus pulls the distal radius fragment proximally and into pronation. The brachioradialis also contributes to proximal migration (shortening) but does not primarily cause the pronation deformity.

Question 674

Topic: Wrist & Carpus

During operative treatment of a Galeazzi fracture in an adult, the radius is anatomically fixed. Intraoperative fluoroscopy and clinical examination reveal the DRUJ is unstable in pronation but stable in neutral and supination. What is the recommended postoperative protocol?

. Transfix the DRUJ with K-wires in pronation for 6 weeks.
. Immobilize the forearm in a long-arm cast or splint in supination for 4 to 6 weeks.
. Perform immediate open repair of the volar radioulnar ligaments.
. Immobilize the forearm in a Muenster cast in pronation for 3 weeks.
. Allow immediate active range of motion to prevent stiffness.

Correct Answer & Explanation

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

Explanation

If the DRUJ is stable in supination after radius fixation, transfixation pinning is not necessary. Immobilization in a long-arm splint or cast in supination (the position of stability) for 4 to 6 weeks is the appropriate management.

Question 675

Topic: 7. Hand and Wrist

Following anatomic reduction and plating of the radius in a Galeazzi fracture, the distal radioulnar joint (DRUJ) remains irreducible. Which of the following structures is most commonly interposed in the DRUJ, preventing reduction?

. Extensor carpi ulnaris tendon
. Flexor carpi ulnaris tendon
. Extensor digiti minimi tendon
. Median nerve
. Pronator quadratus

Correct Answer & Explanation

. Extensor carpi ulnaris tendon

Explanation

The extensor carpi ulnaris (ECU) tendon is the most common structure to become interposed and block reduction of the DRUJ in a Galeazzi fracture-dislocation. Open reduction and extraction of the tendon from the joint is required.

Question 676

Topic: Wrist & Carpus

A patient who underwent volar locked plating of a distal radius fracture 6 months ago presents with sudden inability to actively flex the interphalangeal joint of the thumb. Which of the following technical errors most likely caused this complication?

. Placement of screws that are too long dorsally
. Plate placement distal to the watershed line
. Failure to repair the pronator quadratus
. Iatrogenic injury to the anterior interosseous nerve
. Over-reduction of the volar tilt

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a known complication of volar plating caused by plate prominence distal to the watershed line. The prominent hardware causes attritional wear of the tendon over time.

Question 677

Topic: Wrist & Carpus

A 30-year-old male undergoes ORIF for a Galeazzi fracture. Intraoperative assessment reveals the DRUJ remains unstable in neutral rotation but is stable in full supination. What is the most appropriate postoperative management of the DRUJ?

. Long-arm cast in full supination for 4-6 weeks
. Transfixing the DRUJ with two parallel K-wires in neutral rotation
. Immediate open repair of the triangular fibrocartilage complex (TFCC)
. Dorsal spanning plate across the radiocarpal and DRUJ
. Short-arm cast in neutral rotation to allow early elbow motion

Correct Answer & Explanation

. Long-arm cast in full supination for 4-6 weeks

Explanation

If the DRUJ is unstable in neutral but stable in supination following radial fixation in a Galeazzi fracture, the standard treatment is immobilization in a long-arm splint or cast in full supination for 4-6 weeks. K-wire fixation is reserved for cases unstable in all positions.

Question 678

Topic: 7. Hand and Wrist
A patient with a malunited distal radius fracture presents with ulnar-sided wrist pain. Radiographs demonstrate a radial shortening of 4 mm and a resultant positive ulnar variance. Which of the following conditions is the most likely consequence of this deformity?
. Kienböck's disease
. Scapholunate advanced collapse
. Ulnar impaction syndrome
. Intersection syndrome
. De Quervain tenosynovitis

Correct Answer & Explanation

. Ulnar impaction syndrome

Explanation

Radial shortening leads to a relative positive ulnar variance, which significantly increases load transmission across the ulnocarpal joint. This predisposes the patient to ulnar impaction syndrome and degenerative tears of the TFCC.

Question 679

Topic: 7. Hand and Wrist

A 65-year-old polytraumatized patient presents with a highly comminuted, intra-articular distal radius fracture. The surgeon elects to use a distraction dorsal spanning plate. Between which two bones is the plate typically applied?

. Radius and scaphoid
. Radius and lunate
. Radius and third metacarpal
. Ulna and fourth metacarpal
. Radius and capitate

Correct Answer & Explanation

. Radius and third metacarpal

Explanation

A dorsal spanning plate utilizes the principle of ligamentotaxis to maintain length and alignment in highly comminuted fractures. It is secured to the diaphysis of the radius proximally and the third metacarpal distally, bypassing the carpus.

Question 680

Topic: Wrist & Carpus

A 35-year-old patient undergoes open reduction and internal fixation for a diaphyseal both-bone forearm fracture. Postoperatively, the patient presents with a permanent 30-degree deficit in full supination and pronation. Radiographs reveal a flattened radial contour. Which biomechanical parameter of the radius was most likely inadequately restored during fixation?

. Radial inclination
. Volar tilt
. Maximum radial bow magnitude
. Ulnar variance
. Radial length

Correct Answer & Explanation

. Maximum radial bow magnitude

Explanation

Restoration of the maximum radial bow magnitude is critical for recovering the full arc of forearm pronation and supination. A loss of the radial bow greater than 10% significantly restricts rotational motion, particularly pronation.

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