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 41
Topic: Wrist & Carpus
A 28-year-old male undergoes open reduction and internal fixation for a Galeazzi fracture (middle/distal third radial shaft fracture). Intraoperatively, after rigid plating of the radius, the distal radioulnar joint (DRUJ) is noted to be highly unstable in pronation and neutral, but reduces in supination. What is the most appropriate next step in management?
Correct Answer & Explanation
. Pin the DRUJ with a transverse radioulnar K-wire in supination
Explanation
In a Galeazzi fracture with persistent DRUJ instability after anatomic radius fixation, the joint should be reduced in its most stable position (usually supination) and secured with transverse radioulnar K-wires for 4-6 weeks to allow the TFCC to heal.
Question 42
Topic: Wrist & Carpus
Which of the following radiographic findings in a distal radius fracture is LEAST indicative of potential instability requiring surgical intervention following an initially successful closed reduction?
Correct Answer & Explanation
. Associated ulnar styloid fracture
Explanation
Correct Answer: DInstability criteria often guide the decision for surgical fixation following a distal radius fracture. Common indicators of instability include initial dorsal angulation greater than 20 degrees, radial shortening exceeding 3mm, severe metaphyseal comminution, and particularly, intra-articular step-off or gap greater than 1-2mm. While an ulnar styloid fracture is frequently associated with distal radius fractures and may suggest a TFCC injury, its presencealoneis not a direct criterion forradialfracture instability or a primary indication for surgical intervention on the radius, assuming other parameters are acceptable. It might influence DRUJ stability, but not necessarily the stability of the radial reduction itself.
Question 43
Topic: Wrist & Carpus
Which of the following anatomical structures is considered the primary static stabilizer of the distal radioulnar joint (DRUJ)?
Correct Answer & Explanation
. Triangular Fibrocartilage Complex (TFCC)
Explanation
Correct Answer: CThe Triangular Fibrocartilage Complex (TFCC) is the primary static stabilizer of the DRUJ. It is a complex structure comprising the articular disc, dorsal and volar radioulnar ligaments, and the meniscal homologue. While the dorsal and volar radioulnar ligaments within the TFCC are key components, the TFCC as a whole unit provides the most significant static stability. The interosseous membrane provides some longitudinal stability to the forearm, and the Pronator Quadratus offers dynamic stability. The ECU tendon sheath is adjacent but not a primary stabilizer.
Question 44
Topic: Wrist & Carpus
A 55-year-old female develops symptoms consistent with Complex Regional Pain Syndrome (CRPS) Type I following a distal radius fracture treated non-operatively. Her symptoms include severe pain out of proportion to injury, allodynia, swelling, and trophic changes. Which of the following is considered the MOST critical early intervention in managing CRPS?
Correct Answer & Explanation
. Aggressive physical therapy and occupational therapy
Explanation
Correct Answer: CEarly recognition and aggressive physical and occupational therapy focused on pain-free range of motion, desensitization, and functional use are paramount in managing CRPS. While medications (gabapentin, tricyclic antidepressants) and interventional treatments (sympathetic blocks) have a role, they are often adjuncts. Steroids may be used, but not as the initial most critical step. Spinal cord stimulators are reserved for refractory cases. The key to preventing progression and improving outcomes is early, consistent, and active rehabilitation.
Question 45
Topic: Wrist & Carpus
A 30-year-old active male sustains a distal radius fracture with a 4mm intra-articular step-off, 5 degrees dorsal tilt, and 1mm radial shortening. Which of these parameters ALONE typically warrants surgical intervention for definitive management?
Correct Answer & Explanation
. 4mm intra-articular step-off
Explanation
Correct Answer: AWhile age and activity level influence treatment decisions, the specific fracture characteristic of a 4mm intra-articular step-off is a very strong, if not absolute, indication for surgical management, regardless of other parameters. Even 1-2mm of articular incongruity is often considered unacceptable, particularly in a younger, active individual, due to the high risk of post-traumatic arthritis. The dorsal tilt and radial shortening mentioned are relatively minor compared to the articular step-off.
Question 46
Topic: Wrist & Carpus
In an adult patient with a confirmed Galeazzi fracture-dislocation, what is the generally accepted definitive management strategy?
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 47
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?
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 48
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?
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 49
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?
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 50
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?
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 51
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?
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 52
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?
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 53
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?
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 54
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?
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 55
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?
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 56
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?
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.
Question 57
Topic: Wrist & Carpus
A 24-year-old female sustains a Galeazzi fracture. After achieving rigid anatomic internal fixation of the radius, intraoperative fluoroscopy and clinical examination demonstrate persistent, irreducible DRUJ dislocation in both supination and pronation. What is the most appropriate next step in management?
Correct Answer & Explanation
. Open exploration of the DRUJ and repair of the triangular fibrocartilage complex (TFCC)
Explanation
If the DRUJ remains irreducible or grossly unstable in all positions following rigid fixation of the radius, open exploration is required. The extensor carpi ulnaris (ECU) tendon is a classic anatomic block to DRUJ reduction in Galeazzi fractures.
Question 58
Topic: Wrist & Carpus
A 10-year-old child falls onto an outstretched hand, presenting with localized pain and swelling over the distal forearm and wrist. Radiographs show a fracture of the distal radial diaphysis. In the pediatric population, what is the most common anatomic injury pattern that represents a "Galeazzi equivalent" lesion?
Correct Answer & Explanation
. Distal ulnar physeal separation
Explanation
In pediatric patients, the ligaments of the DRUJ are often stronger than the open growth plates. Therefore, a Galeazzi equivalent fracture involves a distal radius fracture combined with a distal ulnar physeal separation rather than true DRUJ ligamentous disruption.
Question 59
Topic: Wrist & Carpus
Following anatomic rigid internal fixation of the radius for a classic Galeazzi fracture, the surgeon assesses the DRUJ. It is found to be unstable in pronation and neutral rotation, but anatomically reduced and stable in full supination. What is the most appropriate postoperative immobilization strategy?
Correct Answer & Explanation
. Immobilization in a long-arm splint or cast in full supination for 4 to 6 weeks
Explanation
If the DRUJ is reducible and stable in full supination following rigid fixation of the radius, non-operative management of the DRUJ is appropriate. A long-arm cast or splint in supination allows the volar radioulnar ligaments and TFCC to heal.
Question 60
Topic: Wrist & Carpus
A 68-year-old female presents to the emergency department after a low-energy fall onto an outstretched hand. Radiographs reveal a dorsally displaced, comminuted, intra-articular distal radius fracture with 15 degrees of dorsal angulation, 8 mm of radial shortening, and a 3 mm intra-articular step-off involving the lunate fossa. She has no neurovascular deficits. Given her age and fracture characteristics, which of the following findings, if present on a pre-operative CT scan, would be MOST critical to address to prevent long-term post-traumatic arthritis and DRUJ instability?
Correct Answer & Explanation
. A displaced die-punch fragment involving the lunate fossa.
Explanation
Correct Answer: CThe case emphasizes that intra-articular step-off or gap of >1-2 mm is strongly correlated with the development of post-traumatic arthritis. A displaced die-punch fragment, especially involving the lunate fossa, directly contributes to this articular incongruity. The lunate fossa is a critical load-bearing surface, and failure to anatomically reduce a displaced die-punch fragment will lead to altered joint mechanics, progressive cartilage wear, and ultimately, post-traumatic arthritis. While other factors like radial shortening and dorsal angulation contribute to overall wrist dysfunction, direct articular incongruity is the most potent predictor of arthritis. DRUJ instability is often secondary to radial length loss or TFCC injury, but a poorly reduced articular surface can also indirectly affect DRUJ mechanics. A pre-operative CT scan is highly recommended for all displaced intra-articular fractures to precisely identify such fragments and guide surgical reduction to restore articular congruity.Option A (Comminution of the radial styloid) is important for radial length and inclination but less directly impactful on articular congruity than a displaced die-punch fragment.Option B (Non-displaced ulnar styloid fracture) is common and often does not require specific intervention unless associated with gross DRUJ instability, which is not implied by 'non-displaced'.Option D (Mild osteopenia) is a patient factor influencing fixation strategy but not a specific fracture characteristic that directly causes post-traumatic arthritis or DRUJ instability in the same way as articular incongruity.Option E (Non-displaced scaphoid waist fracture) is an associated injury that needs management but, if non-displaced, is less immediately critical for preventing post-traumatic arthritis of the radiocarpal joint than a displaced intra-articular fragment of the distal radius itself.
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