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Wrist & Carpus MCQs

Practice Set 32 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 621

Topic: Wrist & Carpus
A 35-year-old manual laborer presents with chronic, progressive dorsal wrist pain and decreased grip strength. Radiographs reveal sclerosis and fragmentation of the lunate, consistent with Kienböck's disease. Which of the following anatomical variants is most strongly associated with the development of this condition?
. Positive ulnar variance
. Negative ulnar variance
. Scapholunate coalition
. Madelung deformity
. Triquetral hypoplasia

Correct Answer & Explanation

. Negative ulnar variance

Explanation

Kienböck's disease is avascular necrosis of the lunate. While the exact etiology is multifactorial (involving vascular anatomy and trauma), it is strongly associated with negative ulnar variance. Negative ulnar variance occurs when the distal ulna is shorter than the distal radius. This anatomical configuration alters the biomechanics of the wrist, leading to increased shear stress and load transmission directly across the radiolunate joint. Over time, this repetitive microtrauma can compromise the tenuous blood supply to the lunate, precipitating osteonecrosis. Joint leveling procedures (e.g., radial shortening osteotomy) are often performed to unload the lunate in early stages of the disease.

Question 622

Topic: Wrist & Carpus

A 45-year-old female underwent volar locked plating for a displaced distal radius fracture six weeks ago. She now presents with a sudden inability to actively extend her thumb interphalangeal joint. Radiographs confirm anatomic alignment with prominent screw tips projecting past the dorsal cortex. Rupture of the involved tendon typically occurs at the level of which anatomical landmark?

. First dorsal compartment
. Lister's tubercle
. Distal radioulnar joint
. Ulnar styloid process
. Scaphoid tubercle

Correct Answer & Explanation

. Lister's tubercle

Explanation

The extensor pollicis longus (EPL) tendon travels through the third dorsal compartment and uses Lister's tubercle as a pulley. It is highly susceptible to attrition and rupture at this site due to either mechanical friction from prominent dorsal screws or ischemia following a distal radius fracture.

Question 623

Topic: Wrist & Carpus

A 72-year-old female presents with severe pain and instability after falling onto her outstretched hand. Radiographs show a comminuted intra-articular fracture of the distal radius with significant dorsal displacement, ulnar positive variance, and disruption of the distal radioulnar joint (DRUJ). Which classification is most appropriate for this injury, and what is its significance?

. Frykman classification; distinguishes between intra- and extra-articular fractures and associated ulnar styloid fractures.
. Fernandez classification; focuses on fracture mechanism and is useful for surgical planning.
. Universal classification; broadly categorizes based on articular involvement and stability.
. AO/OTA classification; describes fracture morphology based on alpha-numeric codes, highly detailed for research and complex cases.
. Gartland classification; primarily used for supracondylar humerus fractures in children.

Correct Answer & Explanation

. AO/OTA classification; describes fracture morphology based on alpha-numeric codes, highly detailed for research and complex cases.

Explanation

The AO/OTA classification is a comprehensive system that uses alphanumeric codes to describe fracture morphology (e.g., location, articular involvement, comminution) in great detail. For a complex, comminuted intra-articular distal radius fracture with DRUJ disruption, this system provides the most specific and reproducible description for surgical planning, research, and communication among surgeons. While Frykman classifies based on intra/extra-articular involvement and associated ulnar fractures, and Fernandez focuses on mechanism, the AO/OTA provides the highest level of detail for such a complex injury, which is critical for understanding the exact nature of the injury and guiding advanced surgical treatment. The Gartland classification is for pediatric elbow fractures.

Question 624

Topic: Wrist & Carpus

A 40-year-old female presents with persistent pain, stiffness, and catching in her right wrist after a fall. Radiographs are normal. MRI reveals a tear of the triangular fibrocartilage complex (TFCC). Which part of the TFCC is most commonly involved in chronic mechanical symptoms?

. Articular disc
. Meniscus homologue
. Ulnolunate ligament
. Radioulnar ligaments (dorsal and volar)
. Extensor carpi ulnaris (ECU) subsheath

Correct Answer & Explanation

. Radioulnar ligaments (dorsal and volar)

Explanation

The triangular fibrocartilage complex (TFCC) is a critical stabilizer of the distal radioulnar joint (DRUJ) and acts as a cushion for the ulnar carpus. While all parts contribute, tears of the dorsal and volar radioulnar ligaments (RULs) are most commonly associated with instability and chronic mechanical symptoms such as pain, clicking, and reduced grip strength. The articular disc can tear, but the RULs are key for DRUJ stability. The meniscus homologue and ulnolunate ligament are components, but the RULs are paramount for DRUJ integrity. The ECU subsheath is adjacent but not part of the TFCC proper.

Question 625

Topic: Wrist & Carpus

A 64-year-old woman sustains the wrist injury shown in the radiographs. The injury is a volar displaced intra-articular distal radius fracture. When utilizing a volar buttress plate for this specific fracture pattern, what is the primary biomechanical function of the plate?

. To provide dynamic compression across the articular surface
. To act as a tension band against dorsal bending forces
. To neutralize axial loading and volar shearing forces
. To bridge a comminuted metaphyseal defect
. To rigidly lock the radiocarpal joint

Correct Answer & Explanation

. To neutralize axial loading and volar shearing forces

Explanation

Correct Answer: CThe radiographs show a volar Barton's fracture (volar displaced intra-articular fracture of the distal radius). The primary deforming forces are axial loading and volar shear, which cause the carpus to subluxate volarly with the fracture fragment. A volar buttress plate is applied to physically block (buttress) this volar displacement, neutralizing the axial and shearing forces.

Question 626

Topic: Wrist & Carpus

A 64-year-old woman sustains a wrist injury after a fall. Radiographs demonstrate a volar displaced, intra-articular distal radius fracture-dislocation. Which of the following surgical approaches and fixation methods is most appropriate to neutralize the axial loading forces on the fractured fragment?

. Dorsal approach with an angular stable plate
. Volar approach with a buttress plate
. Closed reduction and percutaneous pinning
. Spanning external fixation alone
. Volar approach with headless compression screws only

Correct Answer & Explanation

. Volar approach with a buttress plate

Explanation

Correct Answer: BThe radiographs show a volar Barton's fracture (volar displaced intra-articular distal radius fracture-dislocation). The most biomechanically sound treatment is an open reduction through a volar approach and stabilization with a volar buttress plate. The buttress plate effectively neutralizes the axial loading and shear forces that drive the volar fragment proximally. A dorsal plate cannot provide this buttress effect for a volar shear fracture.

Question 627

Topic: Wrist & Carpus

A 9-year-old girl with Hereditary Multiple Exostoses presents with a progressive forearm deformity. Which of the following best describes the classic deformity pattern seen in this condition?

. Relative radial shortening with ulnar bowing and distal radioulnar joint (DRUJ) dislocation
. Relative ulnar shortening with radial bowing and radial head dislocation
. Isolated proximal radioulnar synostosis
. Volar subluxation of the carpus with excessive radial length
. Symmetric growth arrest of both the radius and ulna

Correct Answer & Explanation

. Relative ulnar shortening with radial bowing and radial head dislocation

Explanation

The classic forearm deformity in HME consists of relative ulnar shortening (due to growth arrest from distal ulnar osteochondromas), secondary bowing of the radius, increased ulnar tilt of the distal radius, and progressive radial head dislocation.

Question 628

Topic: Wrist & Carpus

A 14-year-old male with Hereditary Multiple Exostoses (HME) presents with progressive deformity and limited pronation/supination of his left forearm. Radiographs typically demonstrate which of the following patterns in this condition?

. Relative shortening of the radius with radial bowing
. Relative shortening of the ulna with ulnar deviation of the carpus and bowing of the radius
. Dorsal subluxation of the distal radioulnar joint with a lengthened ulna
. Overgrowth of the radius resulting in a positive ulnar variance
. Premature closure of the proximal radial physis

Correct Answer & Explanation

. Relative shortening of the ulna with ulnar deviation of the carpus and bowing of the radius

Explanation

The classic forearm deformity in HME results from a disproportionately short ulna, which tethers the radius. This causes radial bowing, radial articular angle tilting, and ulnar deviation of the carpus, potentially leading to radial head subluxation.

Question 629

Topic: Wrist & Carpus

A 45-year-old woman undergoes volar locked plating for a distal radius fracture

. At 6 months post-op, she suddenly loses the ability to actively flex her thumb interphalangeal joint. What surgical technical error most likely caused this complication?

. Dorsal screw penetration past the extensor cortex
. Plate placement distal to the watershed line
. Over-tightening of the brachioradialis insertion
. Failure to repair the pronator quadratus
. Placement of the plate deep to the flexor carpi radialis sheath

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Attritional rupture of the flexor pollicis longus (FPL) tendon is a known complication of volar plating for distal radius fractures. It is most commonly caused by placing the plate too far distally, protruding anterior to the watershed line and impinging on the flexor tendons.

Question 630

Topic: Wrist & Carpus

A 60-year-old woman is treated for a dorsally angulated distal radius fracture with a volar locking plate. Six weeks postoperatively, she suddenly loses the ability to actively extend her thumb interphalangeal joint. What is the most likely cause of this complication?

. Irritation and attritional rupture from dorsally prominent screws
. Irritation from a prominent volar plate at the watershed line
. Spontaneous attritional rupture over Lister's tubercle
. Avascular necrosis of the extensor pollicis longus tendon
. Missed iatrogenic laceration during the initial surgical exposure

Correct Answer & Explanation

. Irritation and attritional rupture from dorsally prominent screws

Explanation

Extensor pollicis longus (EPL) tendon rupture following volar plating of the distal radius is most commonly caused by iatrogenic dorsal screw prominence. The screws penetrate the dorsal cortex and cause attritional wear on the overlying extensor tendons.

Question 631

Topic: Wrist & Carpus

A 45-year-old female is 8 weeks status post closed reduction and cast immobilization for a distal radius fracture. She complains of severe, burning pain that is disproportionate to the injury, along with skin color changes and stiffness.

Radiographs show patchy osteopenia. Which intervention has been shown to reduce the incidence of this condition when administered daily following a distal radius fracture?

. Calcium and Vitamin D
. Vitamin C (500 mg daily for 50 days)
. Gabapentin (300 mg TID)
. Prednisone taper over 2 weeks
. Prophylactic stellate ganglion block

Correct Answer & Explanation

. Vitamin C (500 mg daily for 50 days)

Explanation

This patient has Complex Regional Pain Syndrome (CRPS) or Sudeck's atrophy. Daily administration of 500 mg of Vitamin C for 50 days after a distal radius fracture has been shown to significantly decrease the risk of developing CRPS.

Question 632

Topic: Wrist & Carpus

A 45-year-old female is treated conservatively for a distal radius fracture. Eight weeks later, she develops severe burning pain out of proportion to the injury, along with skin changes and stiffness. Radiographs show patchy, periarticular osteopenia.

What is the best pharmacologic prophylaxis that could have been prescribed at the time of injury to reduce her risk of developing this condition?

. Gabapentin
. Vitamin C
. Prednisone
. Amitriptyline
. Ibuprofen

Correct Answer & Explanation

. Vitamin C

Explanation

The patient has Complex Regional Pain Syndrome (CRPS) Type I. Vitamin C (500mg daily for 50 days) has been shown in some studies to reduce the incidence of CRPS following distal radius fractures.

Question 633

Topic: Wrist & Carpus



A 45-year-old female presents 8 weeks after ORIF of a distal radius fracture with severe burning pain, swelling, and shiny skin. Radiographs show patchy osteopenia. Which prophylactic medication given post-operatively could have significantly reduced her risk of developing this condition?

. Calcium supplementation
. Vitamin C (Ascorbic acid)
. Oral bisphosphonates
. Non-steroidal anti-inflammatory drugs
. Pregabalin

Correct Answer & Explanation

. Vitamin C (Ascorbic acid)

Explanation

The patient has Complex Regional Pain Syndrome (CRPS), also known as Sudeck's atrophy. Prophylactic administration of Vitamin C (500 mg daily for 50 days) after a distal radius fracture has been shown to decrease the incidence of CRPS.

Question 634

Topic: Wrist & Carpus

A 55-year-old female sustains a distal radius fracture. To prevent the complication shown in the radiograph

, what pharmacological prophylaxis has historically been recommended during the conservative management of this injury?

. Gabapentin 300mg daily
. Vitamin C 500mg daily
. Ibuprofen 600mg every 8 hours
. Prednisone 10mg daily
. Amitriptyline 25mg nightly

Correct Answer & Explanation

. Vitamin C 500mg daily

Explanation

Vitamin C (500 mg daily for 50 days) has been shown in some studies to reduce the incidence of Complex Regional Pain Syndrome (CRPS) following distal radius fractures. CRPS is characterized by pain out of proportion, sudomotor changes, and patchy osteopenia.

Question 635

Topic: Wrist & Carpus

A 65-year-old woman sustains a displaced distal radius fracture. To reduce the risk of developing the painful condition shown in the radiograph, which is characterized by periarticular patchy osteopenia, which of the following prophylactic measures is recommended?

. Daily calcium and Vitamin D supplementation
. Vitamin C 500 mg daily for 50 days
. Early prophylactic corticosteroid therapy
. Prophylactic stellate ganglion block
. Gabapentin 300 mg daily

Correct Answer & Explanation

. Vitamin C 500 mg daily for 50 days

Explanation

The image demonstrates Sudeck's atrophy (CRPS). Vitamin C (500 mg daily for 50 days) has been shown in some studies to significantly reduce the incidence of CRPS following distal radius fractures.

Question 636

Topic: Wrist & Carpus

A patient develops early-stage CRPS of the upper extremity following a distal radius fracture, presenting with severe sympathetically maintained pain. If conservative management fails, what is the primary sympathetic ganglion targeted for diagnostic and therapeutic nerve blocks?

. Celiac ganglion
. Sphenopalatine ganglion
. Stellate ganglion
. Lumbar sympathetic chain
. Superior cervical ganglion

Correct Answer & Explanation

. Stellate ganglion

Explanation

The stellate ganglion provides sympathetic innervation to the upper extremity. Stellate ganglion blocks are utilized both diagnostically and therapeutically for sympathetically maintained pain in upper extremity CRPS.

Question 637

Topic: Wrist & Carpus

A 45-year-old female sustains a minimally displaced distal radius fracture treated in a cast. Six weeks later, she presents with severe, burning pain out of proportion to her injury, alongside swelling, stiffness, and shiny skin.

Which of the following interventions at the time of injury has been shown to reduce the risk of developing this condition?

. Early passive stretching
. Gabapentin 300mg daily
. Vitamin C 500mg daily
. Prophylactic corticosteroid taper
. Amitriptyline 10mg nightly

Correct Answer & Explanation

. Vitamin C 500mg daily

Explanation

This patient has Complex Regional Pain Syndrome (CRPS) Type I (algodystrophy/Sudeck's atrophy). Administration of Vitamin C (500mg daily for 50 days) starting at the time of injury has been shown in studies to significantly reduce the incidence of CRPS following distal radius fractures.

Question 638

Topic: Wrist & Carpus

A 55-year-old woman is scheduled for closed reduction and casting of a Colles fracture.

What pharmacological agent, when given daily for 50 days post-injury, has been shown in some trials to reduce the incidence of CRPS in distal radius fractures?

. Ibuprofen 400 mg
. Vitamin C 500 mg
. Gabapentin 300 mg
. Amitriptyline 10 mg
. Prednisone 5 mg

Correct Answer & Explanation

. Vitamin C 500 mg

Explanation

Vitamin C (ascorbic acid) at a dose of 500 mg daily for 50 days has been demonstrated in multiple studies to significantly decrease the incidence of Complex Regional Pain Syndrome following distal radius fractures.

Question 639

Topic: Wrist & Carpus

Which of the following anatomical locations is considered extremely rare for the development of Dysplasia Epiphysealis Hemimelica (DEH)?

. Distal femur
. Distal tibia
. Talus
. Distal radius
. Medial femoral condyle

Correct Answer & Explanation

. Distal radius

Explanation

Correct Answer: DDEH usually occurs in the lower limb, with the distal femur, distal tibia, and talus being the most commonly affected sites. Upper limb involvement (such as the distal radius) is considered extremely rare.

Question 640

Topic: Wrist & Carpus

A 4-year-old boy presents with painless swelling of the medial ankle. Imaging shows irregular ossification centers adjacent to the medial malleolus. What is the classic eponymous name for this exact condition?

. Ollier disease
. Trevor disease
. Maffucci syndrome
. Blount disease
. Kienbock disease

Correct Answer & Explanation

. Trevor disease

Explanation

Dysplasia Epiphysealis Hemimelica is classically referred to as Trevor disease, named after David Trevor who described the condition as 'tarso-epiphyseal aclasis'.

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