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7. Hand and Wrist MCQs

Practice Set 148 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 2941

Topic: 7. Hand and Wrist

A 45-year-old manual laborer presents with chronic, progressive wrist pain. He sustained an untreated wrist sprain 10 years ago. Radiographs demonstrate a scaphoid nonunion with advanced arthritic changes at the radioscaphoid and capitolunate joints; however, the radiolunate joint is completely spared.

Which of the following salvage procedures is most appropriate for this patient?

. Scaphoid excision and four-corner fusion
. Proximal row carpectomy
. Total wrist arthrodesis
. Radial styloidectomy alone
. Distal radius osteotomy

Correct Answer & Explanation

. Scaphoid excision and four-corner fusion

Explanation

The patient has Stage 3 Scaphoid Nonunion Advanced Collapse (SNAC), characterized by radioscaphoid and capitolunate arthritis with sparing of the radiolunate joint. Scaphoid excision with four-corner fusion (capitate, lunate, hamate, triquetrum) is the procedure of choice. Proximal row carpectomy (PRC) relies on a preserved capitate head to articulate with the lunate fossa; because the capitolunate joint is arthritic in Stage 3 SNAC, PRC is contraindicated.

Question 2942

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?

. Primary end-to-end repair of the ruptured tendon
. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Thumb interphalangeal joint arthrodesis
. Exploration and tenolysis of the first dorsal compartment
. Abductor pollicis longus (APL) to EPL tendon transfer

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 2943

Topic: Nerve & Tendon

A 50-year-old man presents with chronic numbness in his small and ring fingers, accompanied by intrinsic muscle wasting and a positive Froment's sign. Electromyography confirms severe compression of the ulnar nerve at the elbow. During an in situ ulnar nerve decompression, the surgeon must ensure all potential sites of compression are released. Which of the following is the most common anatomical site of ulnar nerve compression in this region?

. Arcade of Struthers
. Medial intermuscular septum
. Osborne's ligament (cubital tunnel retinaculum)
. Deep flexor pronator aponeurosis
. Guyon's canal

Correct Answer & Explanation

. Arcade of Struthers

Explanation

While the ulnar nerve can be compressed at multiple sites around the elbow (including the arcade of Struthers, the medial intermuscular septum, and the fascial bands between the two heads of the FCU), the most common site of compression is Osborne's ligament, which forms the roof of the cubital tunnel spanning between the medial epicondyle and the olecranon.

Question 2944

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?

. Failure to repair the triangular fibrocartilage complex (TFCC)
. Inadequate fixation of the volar lunate facet fragment
. Iatrogenic rupture of the extensor pollicis longus tendon
. Unrecognized scapholunate ligament tear
. Proximal migration of the radius shaft

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 2945

Topic: 7. Hand and Wrist

A 55-year-old manual laborer presents with chronic wrist pain and weakness. Radiographs reveal a scaphoid nonunion with advanced radioscaphoid arthritis and narrowing of the capitolunate joint space, but the radiolunate joint is preserved. Which of the following is the most appropriate surgical salvage procedure for this patient?

. Scaphoid excision and four-corner fusion
. Proximal row carpectomy (PRC)
. Total wrist arthrodesis
. Radial styloidectomy and scaphoid ORIF with vascularized bone graft
. Radioscapholunate fusion

Correct Answer & Explanation

. Scaphoid excision and four-corner fusion

Explanation

The patient has a Stage III Scaphoid Nonunion Advanced Collapse (SNAC) wrist, characterized by radioscaphoid and capitolunate arthritis with a preserved radiolunate joint. Proximal row carpectomy (PRC) is contraindicated because the capitate head articulates with the lunate fossa; in Stage III, the proximal capitate is arthritic. Therefore, scaphoid excision and four-corner fusion (capitate, lunate, triquetrum, hamate) is the most appropriate motion-preserving salvage procedure.

Question 2946

Topic: Nerve & Tendon

A 28-year-old carpenter presents with an inability to make an 'OK' sign with his right hand. On examination, his thumb interphalangeal joint and index finger distal interphalangeal joint remain extended when attempting to pinch. He has no sensory deficits. Which of the following anatomical variants is a well-known cause of this specific nerve compression syndrome?

. Struthers' ligament
. Gantzer's muscle
. Anconeus epitrochlearis
. Martin-Gruber anastomosis
. Linburg-Comstock anomaly

Correct Answer & Explanation

. Struthers' ligament

Explanation

The patient presents with Anterior Interosseous Nerve (AIN) syndrome, a pure motor palsy affecting the flexor pollicis longus (FPL), flexor digitorum profundus (FDP) to the index/middle fingers, and the pronator quadratus. Gantzer's muscle is an accessory head of the FPL and is a classic anatomical variant that can compress the AIN. Struthers' ligament compresses the main median nerve, anconeus epitrochlearis compresses the ulnar nerve, Martin-Gruber is a normal variant median-to-ulnar nerve anastomosis in the forearm, and Linburg-Comstock is a tendinous interconnection between the FPL and FDP.

Question 2947

Topic: 7. Hand and Wrist

A 30-year-old tennis player complains of dorsal, central wrist pain and a subjective 'clunk' 4 weeks after falling on an outstretched hand. Examination reveals tenderness over the dorsal scapholunate interval. Radiographs show a scapholunate gap of 4 mm and a radiolunate angle of 25 degrees. Which of the following is the most appropriate management for this patient?

. Cast immobilization for 8 weeks
. Arthroscopic debridement of the scapholunate ligament and thermal shrinkage
. Open scapholunate ligament repair and dorsal capsulodesis
. Proximal row carpectomy
. Scaphotrapezio-trapezoid (STT) fusion

Correct Answer & Explanation

. Cast immobilization for 8 weeks

Explanation

The patient has an acute/subacute scapholunate (SL) dissociation with dynamic or static dorsal intercalated segment instability (DISI), indicated by a gap >3 mm and a radiolunate angle >15 degrees. In a young, active patient with a repairable SL tear and no evidence of osteoarthritis, open reduction, direct repair of the SL ligament (often augmented with a dorsal capsulodesis), and temporary K-wire fixation is the standard of care. Salvage procedures (PRC, STT fusion) are reserved for chronic, unrepairable tears or arthritic wrists (SLAC).

Question 2948

Topic: 7. Hand and Wrist

A 40-year-old diabetic patient presents with a severely swollen, painful index finger 3 days after sustaining a puncture wound.

Examination reveals the finger is held in slight flexion, uniform volar swelling, exquisite pain on passive extension, and tenderness along the entire flexor tendon sheath. He requires emergent surgical irrigation and debridement. Which of the following annular pulleys MUST be preserved during the surgical approach to prevent postoperative bowstringing of the flexor tendons?

. A1 and A3 pulleys
. A2 and A4 pulleys
. A1 and A5 pulleys
. C1 and C2 pulleys
. Palmar aponeurosis pulleys

Correct Answer & Explanation

. A1 and A3 pulleys

Explanation

The patient presents with Kanavel's four cardinal signs of purulent flexor tenosynovitis. When performing surgical drainage (via open or dual-incision technique), it is critical to preserve the biomechanically essential A2 (located over the proximal phalanx) and A4 (located over the middle phalanx) pulleys. Loss of these critical pulleys leads to flexor tendon bowstringing, drastically reducing the mechanical advantage and excursion of the tendons, leading to severe functional impairment.

Question 2949

Topic: 7. Hand and Wrist

A 28-year-old laborer presents with chronic wrist pain and is diagnosed with a scaphoid nonunion with a humpback deformity and early radiocarpal arthrosis limited to the radial styloid (SNAC stage I). He has minimal symptoms at rest but pain with heavy gripping. Which of the following is the most appropriate surgical treatment?

. Proximal row carpectomy
. Four-corner arthrodesis
. Scaphoid excision and four-corner fusion
. Radial styloidectomy, volar wedge grafting, and scaphoid fixation
. Total wrist arthrodesis

Correct Answer & Explanation

. Proximal row carpectomy

Explanation

In a young, active patient with a scaphoid nonunion, humpback deformity, and SNAC stage I (arthrosis limited to the radial styloid-scaphoid articulation), the primary goal is to correct the deformity, achieve union, and address the localized arthritis. Volar wedge grafting restores the scaphoid anatomy (correcting the DISI deformity), rigid fixation stabilizes it, and a radial styloidectomy addresses the localized arthrosis. Four-corner fusion or PRC are salvage procedures reserved for more advanced SNAC wrists (Stages II/III).

Question 2950

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?

. Debridement of the central articular disc
. Arthroscopic thermal shrinkage of the TFCC
. Reattachment of the TFCC to the fovea using a bone anchor or transosseous sutures
. Ulnar shortening osteotomy without TFCC repair
. Darrach procedure

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 2951

Topic: 7. Hand and Wrist

A 35-year-old assembly line worker reports a 4-month history of aching pain in the proximal volar forearm and numbness in the thumb, index, and middle fingers. Symptoms worsen with resisted forearm pronation and elbow flexion, but not with prolonged wrist flexion. Electrodiagnostic studies of the median nerve at the wrist are normal. Which of the following physical exam findings best differentiates this condition from Carpal Tunnel Syndrome?

. Positive Tinel's sign at the wrist
. Numbness over the thenar eminence
. Weakness of the abductor pollicis brevis
. Positive Phalen's test
. Wasting of the hypothenar eminence

Correct Answer & Explanation

. Positive Tinel's sign at the wrist

Explanation

The patient's clinical presentation is classic for Pronator Syndrome, a proximal compressive neuropathy of the median nerve in the forearm. A key differentiating factor from Carpal Tunnel Syndrome (CTS) is the presence of sensory disturbances over the thenar eminence. The palmar cutaneous branch of the median nerve provides sensation to the thenar eminence and branches off proximal to the carpal tunnel, traveling superficial to the flexor retinaculum. Therefore, thenar sensation is preserved in CTS but diminished in Pronator Syndrome.

Question 2952

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?

. Placement of the plate proximal to the watershed line
. Penetration of the dorsal cortex with a prominent peg
. Failure to repair the pronator quadratus
. Placement of the plate distal to the watershed line
. Over-distraction of the radiocarpal joint

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 2953

Topic: 7. Hand and Wrist

A 28-year-old manual laborer presents with chronic dorsal wrist pain. Radiographs reveal sclerosis and collapse of the lunate with a fixed flexion deformity of the scaphoid (radioscaphoid angle of 65 degrees) and proximal migration of the capitate. Ulnar variance is neutral. Based on the Lichtman classification, what is the most appropriate definitive surgical intervention?

. Radial shortening osteotomy
. Lunate excision and silastic arthroplasty
. Scaphoid-trapezium-trapezoid (STT) arthrodesis
. Vascularized bone grafting from the distal radius
. Core decompression of the radius

Correct Answer & Explanation

. Radial shortening osteotomy

Explanation

This patient has Stage IIIB Kienbรถck disease, defined by lunate collapse, carpal height collapse, and fixed scaphoid rotary subluxation. Joint-leveling procedures (like radial shortening) and vascularized bone grafts are generally indicated for Stage I, II, or IIIA (prior to carpal collapse). For Stage IIIB, salvage procedures such as an STT fusion, scaphocapitate fusion, or proximal row carpectomy (PRC) are indicated to address the altered carpal kinematics and prevent further collapse.

Question 2954

Topic: 7. Hand and Wrist

A 32-year-old skier falls and sustains a forced hyperabduction injury to his right thumb. Clinical examination reveals 40 degrees of radial deviation laxity at the metacarpophalangeal (MCP) joint with no distinct endpoint. A discrete, tender mass is palpable just proximal to the MCP joint. Which of the following structures is interposed, preventing anatomic healing of the injured ligament and necessitating surgical repair?

. Extensor pollicis brevis tendon
. Abductor pollicis longus tendon
. Adductor pollicis aponeurosis
. First dorsal interosseous muscle
. Flexor pollicis longus tendon

Correct Answer & Explanation

. Extensor pollicis brevis tendon

Explanation

The patient has an acute rupture of the ulnar collateral ligament (UCL) of the thumb MCP joint (Skier's thumb). The clinical presentation of a palpable mass indicates a Stener lesion, which occurs when the torn UCL displaces proximal to the adductor pollicis aponeurosis. The aponeurosis becomes interposed between the ruptured ligament and its insertion on the proximal phalanx, preventing primary healing and establishing an absolute indication for operative repair.

Question 2955

Topic: 7. Hand and Wrist

A 25-year-old carpenter sustains a volar laceration to his index finger at the level of the proximal phalanx, transecting both the FDS and FDP tendons (Zone II). During the primary surgical repair, optimizing flexor tendon gliding and preventing bowstringing is paramount. Preserving or reconstructing which of the following annular pulley combinations is most critical to ensure maximal biomechanical efficiency of the digit?

. A1 and A3
. A2 and A4
. A3 and A5
. C1 and C2
. A1 and A5

Correct Answer & Explanation

. A1 and A3

Explanation

The flexor tendon sheath consists of a series of annular (A) and cruciate (C) pulleys. The A2 pulley (located over the proximal phalanx) and the A4 pulley (located over the middle phalanx) are the major biomechanical pulleys. They are critical for preventing tendon bowstringing and maintaining the appropriate moment arm for digit flexion. Loss of both A2 and A4 results in significant mechanical disadvantage, loss of active range of motion, and fixed flexion contractures.

Question 2956

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?

. Extensor pollicis longus rupture
. Flexor pollicis longus rupture
. Anterior interosseous nerve palsy
. Trigger thumb
. Flexor carpi radialis tendinopathy

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 2957

Topic: 7. Hand and Wrist

A 35-year-old male presents with chronic wrist pain and weakness, noting he sustained a 'sprain' during a football game 5 years ago that was never formally evaluated. Radiographs reveal a scaphoid waist nonunion with advanced degenerative changes at the radioscaphoid and capitolunate joints. The radiolunate articulation is well-preserved. Which of the following is the most appropriate surgical treatment?

. Proximal row carpectomy (PRC)
. Four-corner arthrodesis with scaphoid excision
. Total wrist arthrodesis
. Radial styloidectomy
. Total wrist arthroplasty

Correct Answer & Explanation

. Proximal row carpectomy (PRC)

Explanation

This patient has Stage III Scaphoid Nonunion Advanced Collapse (SNAC). The staging of SNAC is as follows: Stage I involves arthritis isolated to the radial styloid; Stage II involves the entire radioscaphoid joint; Stage III involves the radioscaphoid and capitolunate joints; Stage IV is pancarpal arthritis. Importantly, the proximal pole of the scaphoid and the radiolunate joint are typically spared until very late in the disease process. Because the capitolunate joint is involved (Stage III), proximal row carpectomy (PRC) is contraindicated. PRC requires a pristine capitate head and lunate fossa to form a new articulation. Therefore, four-corner arthrodesis (fusion of the capitate, lunate, hamate, and triquetrum) with scaphoid excision is the standard and most appropriate treatment for this patient.

Question 2958

Topic: Nerve & Tendon

During surgical decompression and anterior transposition of the ulnar nerve for severe cubital tunnel syndrome, the surgeon meticulously releases all potential sites of compression. From proximal to distal, which of the following structures represents the most proximal potential site of ulnar nerve compression in the arm?

. Osborne's ligament
. Medial intermuscular septum
. Arcade of Struthers
. Fascia of the flexor carpi ulnaris (FCU)
. Ligament of Struthers

Correct Answer & Explanation

. Osborne's ligament

Explanation

The Arcade of Struthers is a fascial band located approximately 8 cm proximal to the medial epicondyle, extending from the medial head of the triceps to the medial intermuscular septum. It is the most proximal site of potential ulnar nerve compression. As the ulnar nerve courses distally, other potential compression sites include the medial intermuscular septum, the medial epicondyle itself, Osborne's ligament (the fascial band connecting the humeral and ulnar heads of the flexor carpi ulnaris), and the deep flexor-pronator aponeurosis. Notably, the 'Ligament of Struthers' is a structure associated with a supracondylar process that can compress the median nerve and brachial artery, not the ulnar nerve.

Question 2959

Topic: 7. Hand and Wrist

During an open carpal tunnel release, the surgeon encounters the recurrent motor branch of the median nerve piercing directly through the transverse carpal ligament. According to the Lanz classification, what type of anatomical variant does this represent?

. Extraligamentous
. Subligamentous
. Transligamentous
. Ulnar-sided
. Intraligamentous

Correct Answer & Explanation

. Extraligamentous

Explanation

According to Lanz's classification of the recurrent motor branch of the median nerve, the extraligamentous type is the most common (~50-80%), where the nerve branches distal to the ligament and courses backwards. The transligamentous variant, in which the nerve pierces directly through the transverse carpal ligament, occurs in approximately 20% of individuals. This variant places the nerve at the highest risk for iatrogenic injury during a carpal tunnel release, especially in endoscopic or mini-open procedures if the ligament is divided without complete visualization.

Question 2960

Topic: 7. Hand and Wrist

A 24-year-old male sustains a proximal pole scaphoid fracture. The high risk of avascular necrosis and nonunion in this fracture pattern is primarily due to the unique blood supply to the scaphoid. The predominant blood supply to the scaphoid is derived from branches of which of the following vessels?

. Ulnar artery via the volar carpal arch
. Anterior interosseous artery
. Radial artery via the dorsal carpal branch
. Superficial palmar arch
. Deep palmar arch

Correct Answer & Explanation

. Ulnar artery via the volar carpal arch

Explanation

The scaphoid receives its primary blood supply (70-80%) from the dorsal carpal branch of the radial artery, which enters the scaphoid at the dorsal ridge (near the waist) and supplies the proximal pole in a retrograde fashion. The volar scaphoid branches (also from the radial artery) supply the distal 20-30%. Because of this retrograde flow, fractures at the waist or proximal pole disrupt the blood supply to the proximal fragment, leading to a high rate of avascular necrosis and nonunion.

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