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 321
Topic: Wrist & Carpus
Eight weeks following nonoperative management of a nondisplaced distal radius fracture in a short arm cast, a 60-year-old woman reports the sudden inability to actively extend her thumb interphalangeal joint. What is the most likely etiology of her new deficit?
Correct Answer & Explanation
. Unrecognized scaphoid fracture
Explanation
Extensor pollicis longus (EPL) tendon rupture is a well-known complication of nondisplaced distal radius fractures. It occurs secondary to mechanical attrition or local ischemia within the unreleased third extensor compartment.
Question 322
Topic: Wrist & Carpus
A 55-year-old woman undergoes volar plate fixation for a distal radius fracture. Six months later, she suddenly loses the ability to actively flex the interphalangeal joint of her thumb. What is the most likely cause of this complication?
Correct Answer & Explanation
. Nonunion of the distal radius fracture
Explanation
Prominence of a volar plate distal to the watershed line of the distal radius can cause attritional wear and subsequent rupture of the flexor pollicis longus (FPL) tendon. This presents as a loss of active thumb IP joint flexion.
Question 323
Topic: Wrist & Carpus
A 45-year-old female treated non-operatively for a nondisplaced distal radius fracture presents 6 weeks later unable to actively extend her thumb interphalangeal joint. Tenodesis effect is absent. What is the most appropriate and reliable surgical treatment?
Correct Answer & Explanation
. Primary end-to-end repair of the EPL tendon
Explanation
Extensor pollicis longus (EPL) tendon rupture is a classic complication of nondisplaced distal radius fractures due to ischemia or attrition in the third dorsal compartment. Because the tendon ends retract and degenerate, primary repair is rarely feasible, making an EIP to EPL transfer the gold standard treatment.
Question 324
Topic: Wrist & Carpus
Six months after undergoing volar locked plating for a distal radius fracture, a 55-year-old woman reports sudden inability to actively flex the interphalangeal joint of her thumb. Radiographs reveal the plate was placed distal to the watershed line. What is the most likely cause of her current symptoms?
Correct Answer & Explanation
. Flexor pollicis longus (FPL) tendon rupture
Explanation
Placement of a volar plate distal to the watershed line of the radius increases the risk of flexor tendon attrition and subsequent rupture. The flexor pollicis longus (FPL) is the most commonly affected tendon in this scenario.
Question 325
Topic: Wrist & Carpus
Following volar locked plating of a comminuted distal radius fracture, the patient develops attrition rupture of a tendon due to prominent screws penetrating the dorsal cortex. Which tendon is at greatest risk?
Correct Answer & Explanation
. Extensor carpi radialis longus (ECRL)
Explanation
The Extensor Pollicis Longus (EPL) tendon is highly susceptible to attrition rupture from dorsal screw prominence. It resides in the 3rd extensor compartment and courses around Lister's tubercle, where overpenetrating screws often protrude.
Question 326
Topic: Wrist & Carpus
A 20-year-old gymnast presents with chronic ulnar-sided wrist pain, clicking, and instability after a fall. Examination reveals tenderness over the dorsal TFCC, a positive grind test, and pain with resisted supination. Radiographs are normal. MRI shows a Palmer Type 1B tear of the TFCC. What is the MOST appropriate treatment for this patient?
Correct Answer & Explanation
. Immobilization in a long arm cast for 6 weeks
Explanation
A Palmer Type 1B tear of the TFCC involves a traumatic avulsion of the TFCC from its ulnar insertion, often associated with instability. In a young, active individual like a gymnast, restoration of TFCC stability is paramount to prevent chronic pain, instability, and degenerative changes. Arthroscopic repair, specifically reattachment of the avulsed peripheral TFCC, is the preferred treatment for this type of tear, especially if unstable. Immobilization might be tried initially for stable peripheral tears, but with chronic symptoms and instability, repair is indicated. Ulnar shortening osteotomy is indicated for ulnar positive variance with central (Type 1A) or degenerative (Type 2) tears, not primary traumatic peripheral tears with instability. Arthroscopic debridement is usually for stable, central TFCC tears (Type 1A) or degenerative tears (Type 2). Excision of the ulnar styloid is not a standard treatment for TFCC tears.
Question 327
Topic: Wrist & Carpus
A 40-year-old male sustains a Galeazzi fracture-dislocation. Radiographs show a fracture of the distal third of the radius with associated dorsal dislocation of the distal radioulnar joint (DRUJ). He is an active laborer. What is the MOST appropriate treatment for this injury?
Correct Answer & Explanation
. Closed reduction and long arm cast immobilization
Explanation
A Galeazzi fracture-dislocation (fracture of the distal 1/3 of the radius with associated DRUJ dislocation) is considered an unstable injury. In adults, it almost always requires surgical stabilization. The primary goal is stable fixation of the radial shaft fracture, which, when anatomically reduced, often allows for spontaneous reduction and stabilization of the DRUJ. However, the DRUJ must be carefully assessed intraoperatively for stability after radial fixation. If the DRUJ remains unstable, it requires specific stabilization (e.g., temporary pin fixation across the DRUJ, TFCC repair if indicated). Closed reduction and casting alone are highly prone to failure in adults. ORIF of the radius alone without considering DRUJ stability is incomplete. External fixation is generally reserved for open fractures, severe soft tissue injuries, or highly comminuted fractures not amenable to ORIF. Observation is inappropriate.
Question 328
Topic: Wrist & Carpus
A patient presents 3 months after a distal radius fracture with persistent ulnar-sided wrist pain, clicking, and instability of the distal radioulnar joint (DRUJ). Clinical examination reveals excessive dorsal-palmar translation of the ulna relative to the radius. Radiographs confirm appropriate healing of the distal radius fracture but show mild positive ulnar variance. The TFCC appears attenuated on MRI. What is the MOST appropriate next step in surgical management?
Correct Answer & Explanation
. Ulnar shortening osteotomy
Explanation
The patient presents with chronic, symptomatic DRUJ instability following a distal radius fracture, with excessive translation and an attenuated TFCC, and mild positive ulnar variance. The primary goal is to restore DRUJ stability. Reconstruction of the DRUJ ligaments (e.g., using a tendon graft or capsular plication) along with repair of the TFCC is the most appropriate approach to restore the anatomical constraints of the DRUJ. Ulnar shortening osteotomy addresses positive ulnar variance and can indirectly improve TFCC tension, but it may not fully stabilize a grossly unstable DRUJ with attenuated ligaments. Distal ulna resection (Darrach) or DRUJ arthrodesis (Sauve-Kapandji) are salvage procedures for severe arthritis or painful, irreducible instability. Proximal row carpectomy is for midcarpal arthritis.
Question 329
Topic: Wrist & Carpus
A 55-year-old female presents with the inability to actively flex the interphalangeal joint of her thumb 9 months after undergoing volar locked plating for a distal radius fracture. Radiographs demonstrate that the volar plate is positioned distal to the watershed line of the distal radius. Which of the following tendons is most commonly ruptured in this specific scenario?
Correct Answer & Explanation
. Extensor pollicis longus (EPL)
Explanation
The clinical presentation describes a delayed rupture of the Flexor Pollicis Longus (FPL) tendon, which is a known complication of volar plating of the distal radius. According to the Soong grading classification, plates placed at or distal to the watershed line (Grade 2) are highly prominent and create friction against the overlying flexor tendons, most notably the FPL. EPL ruptures are more commonly associated with non-displaced distal radius fractures or dorsal screw penetration, not prominent volar plates.
Question 330
Topic: Wrist & Carpus
A 60-year-old female is 6 weeks post non-operative management of a minimally displaced distal radius fracture. She suddenly loses the ability to actively extend her thumb interphalangeal joint. Physical exam confirms loss of retropulsion but normal function of the abductor pollicis longus and extensor pollicis brevis. What is the MOST appropriate surgical treatment?
Correct Answer & Explanation
. Extensor pollicis longus (EPL) repair with palmaris longus autograft
Explanation
The patient has suffered a delayed rupture of the extensor pollicis longus (EPL) tendon, a known complication of nondisplaced or minimally displaced distal radius fractures due to ischemia and attrition within the third dorsal compartment. Direct repair is usually impossible due to retracted, frayed tendon ends. The gold standard treatment is an extensor indicis proprius (EIP) to EPL tendon transfer, which restores independent thumb extension without significant morbidity to the index finger.
Question 331
Topic: Wrist & Carpus
A 55-year-old woman is 6 months status post volar locking plate fixation for a comminuted distal radius fracture. She complains of a sudden inability to actively flex the interphalangeal joint of her thumb. Lateral radiographs demonstrate the distal edge of the volar plate is positioned prominently volar to the watershed line. What is the most likely cause of her current presentation?
Correct Answer & Explanation
. Anterior interosseous nerve palsy
Explanation
Positioning a volar plate distal to the watershed line of the distal radius places the flexor tendons at high risk for frictional wear against the plate. The flexor pollicis longus (FPL) tendon is most commonly affected due to its anatomic position directly over the distal radius. This attritional wear can lead to sudden, painless rupture of the FPL, presenting as a loss of active IP joint flexion of the thumb.
Question 332
Topic: Wrist & Carpus
A 65-year-old woman is seen 9 months after undergoing open reduction and internal fixation of a distal radius fracture with a volar locking plate. She reports the sudden onset of an inability to actively flex the interphalangeal joint of her thumb. Passive motion is intact. What is the most likely etiology of this complication?
Correct Answer & Explanation
. Extensor pollicis longus rupture due to prominent dorsal screws
Explanation
Sudden loss of active IP joint flexion of the thumb following volar plating of the distal radius is highly characteristic of a flexor pollicis longus (FPL) tendon rupture. This complication most commonly occurs when the volar plate is placed distal to the watershed line of the distal radius, leading to prominent hardware that causes attritional wear and eventual rupture of the overlying FPL tendon. EPL ruptures (Option 0) result in loss of thumb extension and are more commonly associated with prominent dorsal screws penetrating the dorsal cortex.
Question 333
Topic: Wrist & Carpus
A 50-year-old woman presents with persistent ulnar-sided wrist pain that worsens with pronation and gripping, 1 year after non-operative management of a distal radius fracture.
Radiographs demonstrate a healed distal radius with 4 mm of radial shortening, resulting in positive ulnar variance. MRI reveals degenerative tearing of the triangular fibrocartilage complex (TFCC) and cystic changes in the lunate. The distal radioulnar joint (DRUJ) is congruous without advanced arthritis. What is the most appropriate definitive surgical management?
Correct Answer & Explanation
. Sauvé-Kapandji procedure
Explanation
The patient has ulnar impaction syndrome secondary to a malunited distal radius fracture with significant positive ulnar variance (4 mm). Ulnar shortening osteotomy is the treatment of choice as it decompresses the ulnocarpal joint while maintaining the congruous DRUJ. The arthroscopic wafer procedure is typically reserved for positive ulnar variance of 2 mm or less. Sauvé-Kapandji and Darrach procedures are salvage operations indicated for DRUJ arthritis, which this patient does not have.
Question 334
Topic: Wrist & Carpus
A 55-year-old woman sustained a nondisplaced fracture of the distal radius 6 weeks ago, which was managed conservatively in a short-arm cast. Two days after cast removal, she suddenly loses the ability to actively extend the interphalangeal joint of her thumb.
Radiographs show healing of the distal radius fracture with no displacement. What is the gold standard surgical intervention for this complication?
Correct Answer & Explanation
. Primary end-to-end repair of the ruptured tendon
Explanation
The patient has sustained a spontaneous rupture of the extensor pollicis longus (EPL) tendon, a known complication following distal radius fractures (even nondisplaced ones) due to mechanical attrition and hypovascularity within the third dorsal compartment (Lister's tubercle). Primary end-to-end repair is generally impossible due to tendon retraction and degeneration. The gold standard treatment is an extensor indicis proprius (EIP) to EPL tendon transfer.
Question 335
Topic: Wrist & Carpus
A 65-year-old woman is 6 weeks status post nonoperative cast management of a minimally displaced distal radius fracture. She suddenly loses the ability to actively extend her thumb interphalangeal joint, though she denies any new trauma. What is the gold standard surgical management for this specific complication?
Correct Answer & Explanation
. Primary end-to-end repair of the ruptured tendon
Explanation
This patient has experienced an Extensor Pollicis Longus (EPL) tendon rupture, a classic complication following nondisplaced or minimally displaced distal radius fractures. It is caused by mechanical attrition over Lister's tubercle or vascular ischemia within the third dorsal compartment. Because the tendon ends are typically frayed and retracted, primary repair is rarely feasible. An EIP to EPL tendon transfer is the procedure of choice.
Question 336
Topic: Wrist & Carpus
A 45-year-old man falls from a height and sustains an intra-articular distal radius fracture. CT scan demonstrates a 3-mm displaced, 4-mm wide volar ulnar corner (lunate facet) fragment. He undergoes open reduction and internal fixation with a standard volar locking plate. Two weeks postoperatively, radiographs reveal acute volar subluxation of the carpus. Which of the following is the most likely cause of this complication?
Correct Answer & Explanation
. Failure to repair the triangular fibrocartilage complex (TFCC)
Explanation
The volar ulnar corner (volar lunate facet) is a critical structure for radiocarpal stability, as the short radiolunate ligament originates here. Standard volar locking plates often do not sit sufficiently distal or ulnar to capture this small but crucial fragment. Failure to specifically secure it (via fragment-specific fixation, customized plates, or wire/suture techniques) leads to loss of the volar buttress and subsequent volar radiocarpal subluxation.
Question 337
Topic: Wrist & Carpus
A 24-year-old professional tennis player complains of ulnar-sided wrist pain worsening with forearm rotation and ulnar deviation. MRI reveals a peripheral tear of the triangular fibrocartilage complex (TFCC) at its foveal attachment. Nonoperative management has failed. During arthroscopic repair, which of the following is the most appropriate technique for a Palmer Class 1B tear?
Correct Answer & Explanation
. Debridement of the central articular disc
Explanation
A Palmer Class 1B tear represents a traumatic avulsion of the peripheral attachment of the TFCC to the ulnar fovea (involving the radioulnar ligaments). Because the peripheral zone of the TFCC is well-vascularized, it is highly amenable to primary repair. Reattachment of the TFCC to its anatomic footprint at the fovea using transosseous sutures or a bone anchor restores stability to the distal radioulnar joint (DRUJ). Debridement (Option A) is indicated for central, avascular tears (Class 1A).
Question 338
Topic: Wrist & Carpus
A 55-year-old woman undergoes volar locked plating for a displaced intra-articular distal radius fracture. Six months postoperatively, she presents to the clinic with a sudden inability to actively flex the interphalangeal joint of her thumb. She reports no new trauma. Which of the following technical errors during the index procedure is the most likely cause of this complication?
Correct Answer & Explanation
. Placement of the plate proximal to the watershed line
Explanation
The patient has suffered a flexor pollicis longus (FPL) tendon rupture, which is a known complication of volar plating of the distal radius. This typically occurs due to attritional wear of the tendon over a prominent volar plate that is placed too far distal, specifically distal to the 'watershed line' (the bony prominence on the volar aspect of the distal radius). Prominent dorsal pegs would cause extensor tendon irritation or rupture.
Question 339
Topic: Wrist & Carpus
A 55-year-old woman presents with the inability to actively flex the interphalangeal joint of her right thumb. She underwent open reduction and internal fixation of a distal radius fracture with a volar locking plate 8 months ago. Radiographs reveal that the plate is positioned distal to the watershed line of the distal radius. What is the most likely etiology of her current deficit?
Correct Answer & Explanation
. Extensor pollicis longus rupture
Explanation
Flexor pollicis longus (FPL) rupture is a known complication of volar plating of the distal radius. It typically occurs when the plate is placed distal to the watershed line, which is the most prominent volar margin of the distal radius. Implants placed distal to this line can impinge on the flexor tendons, causing attritional wear and eventual rupture of the FPL tendon. An anterior interosseous nerve palsy would also cause loss of thumb IP joint flexion, but given the timeline and radiographic findings of a prominent volar plate, attritional tendon rupture is the most likely diagnosis. Extensor pollicis longus (EPL) rupture is more commonly associated with nondisplaced distal radius fractures or dorsal prominent screws.
Question 340
Topic: Wrist & Carpus
A 55-year-old female presents 6 months after a volar locking plate fixation of a distal radius fracture. She complains of suddenly losing the ability to actively flex the interphalangeal joint of her thumb. Radiographs show the fracture has healed, but the plate was placed on and slightly distal to the watershed line. Which of the following tendons is most commonly ruptured in this scenario?
Correct Answer & Explanation
. Flexor digitorum profundus to the index finger
Explanation
The flexor pollicis longus (FPL) tendon is at the highest risk for iatrogenic attritional rupture following volar plate fixation of distal radius fractures, particularly when the hardware is placed at or distal to the watershed line. The prominent distal edge of the plate causes friction and attritional wear of the overlying FPL tendon. Conversely, Extensor pollicis longus (EPL) ruptures are more common with non-operative management of nondisplaced distal radius fractures (due to ischemia or callus in the 3rd dorsal compartment) or from dorsally protruding screws piercing the dorsal cortex.
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