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Wrist & Carpus MCQs

Practice Set 8 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 141

Topic: Wrist & Carpus

A patient is diagnosed with a peripheral, foveal avulsion of the Triangular Fibrocartilage Complex (TFCC), classified as a Palmer 1B lesion. To restore stability to the distal radioulnar joint (DRUJ), which specific anatomical structures within the TFCC must be anatomically repaired to the fovea?

. The central articular disc
. The extensor carpi ulnaris (ECU) subsheath
. The deep (ligamentum subcruentum) fibers of the dorsal and volar radioulnar ligaments
. The ulnolunate and ulnotriquetral ligaments
. The meniscal homologue

Correct Answer & Explanation

. The deep (ligamentum subcruentum) fibers of the dorsal and volar radioulnar ligaments

Explanation

The primary stabilizers of the Distal Radioulnar Joint (DRUJ) are the dorsal and volar radioulnar ligaments. The deep fibers of these ligaments converge and attach to the fovea at the base of the ulnar styloid. An anatomic repair of a Palmer 1B foveal avulsion must reattach these deep fibers to the fovea to appropriately restore DRUJ mechanics and stability.

Question 142

Topic: Wrist & Carpus

A 26-year-old male presents with a persistent scaphoid nonunion and avascular necrosis of the proximal pole, featuring a humpback deformity and a 6 mm bone defect. Which of the following graft options provides both the structural integrity to correct the deformity and the robust blood supply necessary for this specific scenario?

. 1,2 Intercompartmental supraretinacular artery (ICSRA) pedicled graft
. Free vascularized medial femoral condyle (MFC) bone graft
. Non-vascularized iliac crest bone graft
. Vascularized distal radius bone graft pedicled on the pronator quadratus
. Demineralized bone matrix with platelet-rich plasma

Correct Answer & Explanation

. Free vascularized medial femoral condyle (MFC) bone graft

Explanation

The free vascularized medial femoral condyle (MFC) graft provides necessary structural support to correct large defects (>5 mm) and humpback deformities, along with a robust blood supply essential for healing AVN.

Question 143

Topic: Wrist & Carpus

During an Adams-Berger anatomic reconstruction of the distal radioulnar joint (DRUJ) for chronic instability, a tendon graft is utilized to recreate the palmar and dorsal radioulnar ligaments. Where are the graft ends passed through the radius?

. Through tunnels at the dorsal and volar margins of the sigmoid notch
. Directly through the anatomic center of the radial styloid
. Around Lister's tubercle and sutured to the brachioradialis insertion
. Through the central medullary canal of the distal radius
. Subperiosteally along the volar metaphysis of the radius

Correct Answer & Explanation

. Through tunnels at the dorsal and volar margins of the sigmoid notch

Explanation

The Adams-Berger procedure reconstructs the radioulnar ligaments using a graft passed through an isometric tunnel in the ulnar fovea and secured through tunnels at the dorsal and volar margins of the sigmoid notch.

Question 144

Topic: Wrist & Carpus

A 25-year-old male presents with a scaphoid nonunion demonstrating a humpback deformity and avascular necrosis of the proximal pole on MRI. The proximal fragment measures 6 mm. Which of the following is the most appropriate vascularized bone graft to restore scaphoid geometry and maximize the likelihood of union?

. 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) graft
. Pedicled pronator quadratus bone graft
. Free medial femoral condyle vascularized bone graft
. Pedicled capitate vascularized bone graft
. Non-vascularized iliac crest bone graft

Correct Answer & Explanation

. Free medial femoral condyle vascularized bone graft

Explanation

A free medial femoral condyle vascularized bone graft provides structural corticocancellous bone capable of correcting a humpback deformity while revascularizing the proximal pole. Pedicled distal radius grafts like the 1,2 ICSRA are often too thin to correct significant humpback deformities and have higher failure rates in advanced AVN.

Question 145

Topic: Wrist & Carpus

A 65-year-old woman presents 8 weeks after open reduction and internal fixation of a distal radius fracture with a volar locking plate. She suddenly lost the ability to actively extend her thumb interphalangeal joint. Radiographs show prominent screws penetrating the dorsal cortex. What is the most reliable surgical treatment for this complication?

. Primary end-to-end repair of the ruptured tendon
. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Free tendon graft using the palmaris longus
. Tenodesis of the EPL to the extensor carpi radialis brevis
. Arthrodesis of the thumb interphalangeal joint

Correct Answer & Explanation

. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer

Explanation

Prominent dorsal screws from volar plating commonly cause attritional rupture of the Extensor Pollicis Longus (EPL) tendon. Primary repair is usually impossible due to retracted, frayed tendon ends; therefore, an EIP to EPL transfer is the gold standard treatment.

Question 146

Topic: Wrist & Carpus

A 19-year-old gymnast presents with chronic ulnar-sided wrist pain. MRI demonstrates a central, avascular tear of the triangular fibrocartilage complex (TFCC) with no evidence of distal radioulnar joint (DRUJ) instability. Ulnar variance is neutral. What is the preferred surgical treatment?

. Open repair of the TFCC to the fovea
. Arthroscopic debridement of the central tear
. Ulnar shortening osteotomy
. Darrach procedure
. Bowers hemiresection interposition arthroplasty

Correct Answer & Explanation

. Arthroscopic debridement of the central tear

Explanation

Central TFCC tears occur in the avascular zone and lack healing potential. In a stable DRUJ with neutral ulnar variance, arthroscopic debridement is the preferred treatment. Peripheral tears are vascularized and amenable to repair.

Question 147

Topic: Wrist & Carpus

A 25-year-old man sustains a Galeazzi fracture. Radiographs show a fracture of the distal third of the radial shaft with dislocation of the distal radioulnar joint (DRUJ). Which structure is the primary stabilizer of the DRUJ that is disrupted in this injury pattern?

. Extensor carpi ulnaris tendon sheath
. Triangular fibrocartilage complex (TFCC)
. Interosseous membrane
. Volar radiocarpal ligaments
. Pronator quadratus

Correct Answer & Explanation

. Triangular fibrocartilage complex (TFCC)

Explanation

The triangular fibrocartilage complex (TFCC) is the primary stabilizing structure of the DRUJ. In a Galeazzi fracture-dislocation, the DRUJ is disrupted, implying a significant tear or avulsion of the TFCC that must be addressed if the joint remains unstable after radius fixation.

Question 148

Topic: Wrist & Carpus

You are performing a volar (Henry) approach to the distal radius for open reduction and internal fixation of a distal radius fracture. After developing the interval between the flexor carpi radialis (FCR) tendon and the radial artery, which muscle must be reflected from radial to ulnar to adequately expose the volar surface of the distal radius?

. Flexor digitorum superficialis (FDS)
. Flexor pollicis longus (FPL)
. Pronator quadratus (PQ)
. Brachioradialis
. Flexor carpi ulnaris (FCU)

Correct Answer & Explanation

. Pronator quadratus (PQ)

Explanation

During the volar Henry approach to the distal radius, the deep dissection involves elevating the pronator quadratus (PQ) muscle. The PQ is carefully elevated from its radial insertion (leaving a small cuff of tissue for later repair) and reflected ulnarly to expose the volar cortex of the distal radius. This protects the anterior interosseous nerve (AIN) and artery, which travel deep to the PQ.

Question 149

Topic: Wrist & Carpus

A 55-year-old male with a history of a remote distal radius fracture presents with difficulty extending his fingers and thumb, but normal sensory examination. He exhibits pain approximately 4 cm distal to the lateral epicondyle on resisted supination. Which structure is the most common site of compression for the nerve affected in this syndrome?

. Ligament of Struthers
. Lacertus fibrosus
. Arcade of Frohse
. Leash of Henry
. Distal edge of the supinator muscle

Correct Answer & Explanation

. Arcade of Frohse

Explanation

The clinical presentation describes Posterior Interosseous Nerve (PIN) syndrome, characterized by weakness in thumb and finger extension without sensory loss (as the superficial radial nerve branches off proximal to the compression). The most common site of PIN compression is the Arcade of Frohse, which is the thickened proximal aponeurotic edge of the superficial head of the supinator muscle.

Question 150

Topic: Wrist & Carpus

A patient with Ulnar Impaction Syndrome presents with chronic ulnar-sided wrist pain. Diagnostic arthroscopy reveals a Palmer Type 2C tear of the Triangular Fibrocartilage Complex (TFCC), characterized by a central perforation, chondromalacia of the ulnar head, and a complete tear of the lunotriquetral (LT) interosseous ligament. Ulnar variance is measured at +3 mm. What is the most appropriate surgical treatment?

. Arthroscopic Wafer procedure
. Ulnar shortening osteotomy
. Darrach procedure
. Sauve-Kapandji procedure
. Open direct repair of the central TFCC perforation

Correct Answer & Explanation

. Ulnar shortening osteotomy

Explanation

In a patient with Ulnar Impaction Syndrome and positive ulnar variance of +3 mm, especially in the presence of a concomitant lunotriquetral (LT) ligament tear (Palmer 2C), an ulnar shortening osteotomy (USO) is the treatment of choice. USO unloads the ulnocarpal joint and has the added biomechanical advantage of tightening the ulnocarpal ligaments (ulnolunate and ulnotriquetral), which helps stabilize the incompetent LT joint. The Wafer procedure is typically reserved for positive variance of <2 mm and does not tighten the ulnocarpal ligaments. Central TFCC tears (degenerative) are typically debrided, not repaired.

Question 151

Topic: Wrist & Carpus
A 40-year-old carpenter presents with ulnar-sided wrist pain. Radiographs show a +3 mm ulnar variance with cystic changes in the lunate and ulnar head. MRI demonstrates a central perforation of the triangular fibrocartilage complex (TFCC). Arthroscopy confirms the TFCC tear but shows pristine, intact articular cartilage at the distal radioulnar joint (DRUJ). What is the most appropriate surgical treatment?
. Darrach procedure
. Sauvé-Kapandji procedure
. Ulnar shortening osteotomy
. Ulnar head replacement
. Arthroscopic wafer procedure

Correct Answer & Explanation

. Ulnar shortening osteotomy

Explanation

This patient has Ulnar Impaction Syndrome with a large positive ulnar variance (+3 mm) and intact DRUJ cartilage. The gold standard treatment for ulnar impaction with intact DRUJ cartilage and >2 mm of positive variance is an ulnar shortening osteotomy (USO). The arthroscopic wafer procedure is generally limited to patients with <2 mm of positive variance. The Darrach and Sauvé-Kapandji procedures are salvage operations indicated when there is concurrent DRUJ arthritis, which this patient does not have.

Question 152

Topic: Wrist & Carpus
A 40-year-old heavy laborer presents with severe, symptomatic post-traumatic distal radioulnar joint (DRUJ) osteoarthritis. He requires preservation of maximum grip strength and forearm rotation for work. Which of the following salvage procedures is designed to eliminate DRUJ pain while explicitly preserving the ulnocarpal ligament complex and carpal support?
. Sauvé-Kapandji procedure
. Darrach procedure
. Hemiresection interposition arthroplasty (Bowers)
. Distal ulna prosthetic replacement
. Ulnar shortening osteotomy

Correct Answer & Explanation

. Sauvé-Kapandji procedure

Explanation

The Sauvé-Kapandji procedure involves arthrodesis of the DRUJ with a creation of a pseudoarthrosis in the distal ulnar metaphysis to allow forearm rotation. Because the ulnar head remains securely articulated and fused with the sigmoid notch, the ulnocarpal ligaments and triangular fibrocartilage complex (TFCC) attachments are preserved, maintaining ulnocarpal support and minimizing ulnar translation of the carpus. The Darrach procedure removes the distal ulna entirely, sacrificing this support.

Question 153

Topic: Wrist & Carpus

A 28-year-old man sustains a Galeazzi fracture-dislocation (fracture of the distal third of the radius with associated distal radioulnar joint [DRUJ] disruption). Following rigid plate fixation of the radius, intraoperative assessment reveals that the DRUJ subluxates dorsally when the forearm is in pronation but completely reduces and is stable when the forearm is placed in supination. What is the most appropriate management of the DRUJ?

. Immobilization of the forearm in supination for 4 to 6 weeks
. Immobilization of the forearm in pronation for 4 to 6 weeks
. Immediate open reduction and primary repair of the triangular fibrocartilage complex (TFCC)
. Transfixion pinning of the DRUJ with the forearm in neutral rotation
. Resection of the distal ulna (Darrach procedure)

Correct Answer & Explanation

. Immobilization of the forearm in supination for 4 to 6 weeks

Explanation

In a classic Galeazzi fracture, after anatomic and rigid fixation of the radius, the DRUJ must be assessed. If the DRUJ reduces and is stable in a specific position (most commonly supination for a dorsal DRUJ dislocation), the standard of care is closed management with immobilization (sugar-tong splint or long arm cast) in that stable position (supination) for 4 to 6 weeks. Pinning or open repair is reserved for DRUJs that remain unstable in all positions of rotation or are irreducible.

Question 154

Topic: Wrist & Carpus
A 45-year-old active mechanic complains of severe ulnar-sided wrist pain and DRUJ instability 1 year after nonoperative treatment of a distal radius fracture. Radiographs show a distal radius malunion with 25 degrees of dorsal tilt and 5 mm of positive ulnar variance. What is the best surgical management?
. Darrach procedure
. Sauvé-Kapandji procedure
. Ulnar shortening osteotomy
. Distal radius corrective osteotomy with structural bone graft and volar plating
. Hemiresection interposition arthroplasty (Bowers procedure)

Correct Answer & Explanation

. Distal radius corrective osteotomy with structural bone graft and volar plating

Explanation

In a young, active patient with a symptomatic distal radius malunion causing secondary DRUJ incongruity and instability, the ideal treatment is to correct the primary deformity. A corrective opening wedge osteotomy of the distal radius with a structural bone graft and rigid fixation restores normal anatomy, corrects the relative positive ulnar variance, and realigns the DRUJ, thereby preserving joint mechanics.

Question 155

Topic: Wrist & Carpus
A 30-year-old man with Lichtman Stage II Kienböck's disease undergoes a joint-leveling procedure and a pedicled vascularized bone graft from the dorsal distal radius based on the 4+5 Extensor Compartmental Artery (ECA). Anatomically, this vascular pedicle is harvested between which two extensor compartments?
. First and Second
. Second and Third
. Third and Fourth
. Fourth and Fifth
. Fifth and Sixth

Correct Answer & Explanation

. Third and Fourth

Explanation

Pedicled vascularized bone grafts from the dorsal distal radius are a standard treatment for Kienböck's disease. The 4+5 ECA (extensor compartmental artery) graft is harvested from the dorsal radius with its pedicle lying between the fourth dorsal compartment (extensor digitorum communis, extensor indicis proprius) and the fifth dorsal compartment (extensor digiti minimi).

Question 156

Topic: Wrist & Carpus
In a patient with Stage III Scapholunate Advanced Collapse (SLAC) wrist, the radiolunate joint is characteristically spared from degenerative changes. Which of the following biomechanical or anatomic factors is the primary reason for this preservation?
. The robust interosseous blood supply to the lunate
. The shielding effect of the intact triangular fibrocartilage complex (TFCC)
. The elliptical articulation of the radiolunate joint that disperses sheer stress
. The congruent spherical articulation of the radiolunate joint
. The absence of rotational forces on the lunate following scapholunate dissociation

Correct Answer & Explanation

. The congruent spherical articulation of the radiolunate joint

Explanation

In SLAC wrist, the radiolunate joint is typically spared from osteoarthritis due to its congruent spherical articulation. When the scaphoid rotates into a flexed position, its elliptical proximal pole creates incongruous point-loading on the scaphoid fossa of the radius, leading to rapid degeneration (Stage I and II). The lunate, however, maintains a spherical, congruent relationship with the lunate fossa even when extended (DISI deformity), evenly distributing forces and sparing the cartilage.

Question 157

Topic: Wrist & Carpus

A 55-year-old woman presents to the clinic unable to actively extend the interphalangeal joint of her thumb. She was treated non-operatively 6 weeks ago for a non-displaced distal radius fracture. What is the primary pathophysiological cause of this late complication?

. Iatrogenic transaction of the tendon during a hematoma block
. Mechanical attrition and local ischemia of the tendon at Lister's tubercle
. Entrapment of the tendon within the healing fracture site
. Primary osteoarthritis of the carpometacarpal joint
. Compression of the nerve by the extensor retinaculum

Correct Answer & Explanation

. Mechanical attrition and local ischemia of the tendon at Lister's tubercle

Explanation

Spontaneous rupture of the extensor pollicis longus (EPL) tendon is a classic complication that occurs weeks after a non-displaced distal radius fracture. It is primarily caused by mechanical attrition from bony irregularity at Lister's tubercle, compounded by localized ischemia of the tendon within the unyielding third extensor compartment due to fracture hematoma and swelling.

Question 158

Topic: Wrist & Carpus

During volar locking plate fixation of a distal radius fracture, the surgeon accidentally places a screw that protrudes through the dorsal cortex of the distal radius into the third extensor compartment. Which tendon is at the highest risk for attrition and rupture?

. Extensor digitorum communis
. Extensor carpi radialis longus
. Extensor pollicis longus
. Extensor indicis proprius
. Extensor carpi radialis brevis

Correct Answer & Explanation

. Extensor pollicis longus

Explanation

Prominent dorsal screws protruding through the third extensor compartment specifically place the Extensor Pollicis Longus (EPL) tendon at risk for attritional rupture. Proper screw length measurement is critical to avoid this complication.

Question 159

Topic: Wrist & Carpus

Six months following open reduction and internal fixation of a distal radius fracture with a volar locking plate, a 55-year-old woman is unable to actively flex the interphalangeal joint of her thumb. Which of the following technical errors during the index procedure is the most likely cause of this complication?

. Placement of the plate proximal to the watershed line
. Prominence of the plate distal to the watershed line
. Drilling past the dorsal cortex with a sharp drill bit
. Failure to repair the pronator quadratus during closure
. Use of locking screws that are too long in the distal row

Correct Answer & Explanation

. Prominence of the plate distal to the watershed line

Explanation

Rupture of the flexor pollicis longus (FPL) tendon is a well-recognized complication of volar plating of the distal radius. It is most commonly caused by hardware prominence distal to the watershed line (the most volar margin of the radius). The tendon glides over the sharp distal edge of the plate, leading to attritional rupture. Placement proximal to the watershed line is the correct technique to avoid this. Long distal screws would cause extensor tendon rupture, not flexor.

Question 160

Topic: Wrist & Carpus

In Scaphoid Nonunion Advanced Collapse (SNAC), degenerative changes progress through the wrist in a predictable anatomical sequence. Which of the following joints is typically the LAST to develop osteoarthritic changes and is specifically spared in early to middle stages?

. Radioscaphoid joint
. Capitolunate joint
. Radiolunate joint
. Scaphotrapezial-trapezoidal (STT) joint
. Distal radioulnar joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

In both SNAC and SLAC (Scapholunate Advanced Collapse) patterns of wrist arthritis, the radiolunate joint is characteristically spared until the absolute latest stages of the disease. This is because the lunate maintains its congruency within the spherical lunate fossa of the distal radius, a concept central to the rationale for performing a four-corner fusion or proximal row carpectomy, both of which rely on a preserved radiolunate articulation.

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