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7. Hand and Wrist MCQs

Practice Set 24 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 461

Topic: 7. Hand and Wrist
According to Mayfield's progressive stages of perilunate instability, what anatomical disruption characterizes the final stage (Stage IV) of the injury sequence?
. Scapholunate dissociation
. Lunotriquetral disruption
. Volar dislocation of the lunate
. Dorsal dislocation of the capitate
. Disruption of the radiocarpal ligaments

Correct Answer & Explanation

. Volar dislocation of the lunate

Explanation

Mayfield Stage IV represents a complete volar lunate dislocation into the carpal tunnel. The sequence is: I (scapholunate dissociation), II (perilunate dislocation with capitate dorsal), III (lunotriquetral disruption), and IV (volar lunate dislocation).

Question 462

Topic: Hand Trauma & Infection

A patient presents with a swollen, painful index finger 3 days after a minor puncture wound. Of Kanavel's four cardinal signs of flexor tenosynovitis, which is typically considered the earliest and most sensitive finding?

. Fusiform swelling of the entire digit
. Flexed resting posture of the digit
. Tenderness along the entire course of the flexor tendon sheath
. Pain with passive extension of the digit

Correct Answer & Explanation

. Pain with passive extension of the digit

Explanation

Pain with passive extension of the digit is generally considered the earliest and most sensitive sign of infectious pyogenic flexor tenosynovitis. It effectively stretches the inflamed tendon sheath, eliciting immediate, disproportionate pain.

Question 463

Topic: Wrist & Carpus

When performing internal fixation of a proximal pole scaphoid fracture, which surgical approach provides the most direct access for optimal screw trajectory without violating the radiocarpal articular surface?

. Volar approach through the bed of the flexor carpi radialis (FCR)
. Dorsal approach between the third and fourth extensor compartments
. Mid-lateral radial approach through the anatomic snuffbox
. Volar approach between the radial artery and FCR
. Dorsal approach between the first and second extensor compartments

Correct Answer & Explanation

. Dorsal approach between the third and fourth extensor compartments

Explanation

The dorsal approach (often utilizing the interval between the 3rd and 4th compartments) is preferred for proximal pole scaphoid fractures. It allows central screw placement directly down the longitudinal axis of the scaphoid without damaging the articular surface.

Question 464

Topic: Hand Trauma & Infection
A patient with a human bite wound over the third metacarpophalangeal joint grows a fastidious Gram-negative rod that forms 'pit' colonies on agar. Which of the following antibiotics is this organism predictably resistant to?
. Amoxicillin-clavulanate
. Ampicillin
. Clindamycin
. Cefoxitin
. Trimethoprim-sulfamethoxazole

Correct Answer & Explanation

. Amoxicillin-clavulanate

Explanation

Eikenella corrodens is a common pathogen in human 'fight bite' injuries. It is classically susceptible to penicillin and amoxicillin but notoriously resistant to clindamycin and first-generation cephalosporins.

Question 465

Topic: Wrist & Carpus
A 45-year-old male presents with chronic wrist pain and a scaphoid nonunion. Radiographs demonstrate degenerative changes isolated to the radioscaphoid and scaphocapitate joints. The radiolunate articulation is preserved. What is the SNAC classification and an appropriate surgical option?
. SNAC Stage I treated with proximal row carpectomy
. SNAC Stage II treated with scaphoid excision and four-corner fusion
. SNAC Stage III treated with radial styloidectomy
. SNAC Stage IV treated with a total wrist arthrodesis
. SNAC Stage I treated with scaphoid excision alone

Correct Answer & Explanation

. SNAC Stage II treated with scaphoid excision and four-corner fusion

Explanation

SNAC Stage II involves arthritis of the radioscaphoid and scaphocapitate joints. Appropriate salvage options include scaphoid excision with four-corner fusion or a proximal row carpectomy (if the capitate head is preserved).

Question 466

Topic: 7. Hand and Wrist

The primary blood supply to the proximal pole of the scaphoid, making it susceptible to avascular necrosis after fracture, is derived from which of the following vessels?

. Volar carpal branch of the radial artery entering distally
. Dorsal carpal branch of the radial artery entering via the dorsal ridge
. Superficial palmar arch entering the distal tubercle
. Anterior interosseous artery entering the proximal articular surface
. Ulnar artery via the deep palmar arch

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery entering via the dorsal ridge

Explanation

The scaphoid receives 70-80% of its blood supply from the dorsal carpal branch of the radial artery, which enters at the dorsal ridge and supplies the proximal pole in a retrograde fashion.

Question 467

Topic: 7. Hand and Wrist

In a Bennett fracture-dislocation of the thumb carpometacarpal joint, what deforming force is primarily responsible for the dorsal, proximal, and radial displacement of the main metacarpal shaft?

. Adductor pollicis
. Abductor pollicis longus
. Extensor pollicis longus
. Flexor pollicis longus
. Anterior oblique ligament

Correct Answer & Explanation

. Abductor pollicis longus

Explanation

In a Bennett fracture, the volar ulnar beak fragment is held by the anterior oblique ligament. The main metacarpal shaft is displaced dorsally, proximally, and radially by the pull of the abductor pollicis longus (APL).

Question 468

Topic: 7. Hand and Wrist

A 25-year-old male sustains a 'fight bite' over his third MCP joint. In the ER, the finger is explored in full extension and the joint capsule appears intact. He is discharged but returns 3 days later with septic arthritis. What anatomic principle explains the initial missed intra-articular injury?

. Sagittal band subluxation obscures the capsular defect
. The lumbrical muscle covers the capsular defect in extension
. The extensor tendon and capsule glide proximally when the finger is extended
. The volar plate retracts dorsally during extension
. The collateral ligaments become lax in extension hiding the puncture

Correct Answer & Explanation

. The extensor tendon and capsule glide proximally when the finger is extended

Explanation

Fight bites occur with a clenched fist. When the hand is subsequently extended for examination, the lacerated extensor tendon and dorsal capsule glide proximally, hiding the entry path into the joint.

Question 469

Topic: 7. Hand and Wrist

A 20-year-old male falls on an outstretched hand and has anatomic snuffbox tenderness, but initial radiographs are negative. Which imaging modality is considered the most sensitive and specific for detecting an occult scaphoid fracture within 24 hours of injury?

. Repeat plain radiographs with scaphoid views
. Computed tomography (CT) scan without contrast
. Magnetic resonance imaging (MRI)
. Technetium-99m bone scintigraphy
. High-resolution ultrasound

Correct Answer & Explanation

. Magnetic resonance imaging (MRI)

Explanation

MRI is the most sensitive and specific modality for diagnosing occult scaphoid fractures in the acute setting (<24-48 hours) as it easily detects the associated bone marrow edema. CT is highly specific but less sensitive acutely.

Question 470

Topic: 7. Hand and Wrist

A 30-year-old male sustains a trans-scaphoid perilunate dislocation after falling from a roof. According to the Mayfield classification system, this injury pattern is best described as which of the following?

. Lesser arc injury
. Greater arc injury
. Purely ligamentous disruption
. Madelung deformity equivalent
. Galeazzi equivalent

Correct Answer & Explanation

. Greater arc injury

Explanation

Perilunate injuries are classified into lesser arc (purely ligamentous) and greater arc (involving fractures of the surrounding carpal bones). A trans-scaphoid perilunate dislocation is a classic greater arc injury.

Question 471

Topic: 7. Hand and Wrist

A 28-year-old male sustains a proximal pole scaphoid fracture. The treating surgeon counsels the patient on the high risk of avascular necrosis. Which of the following anatomical characteristics is primarily responsible for the increased incidence of avascular necrosis in this specific fracture pattern?

. The scaphoid receives entirely volar blood supply through the superficial palmar arch.
. The primary blood supply enters at the distal pole and provides retrograde perfusion to the proximal pole.
. The proximal pole lacks any cartilaginous covering, limiting diffusion of synovial nutrient fluid.
. The radioscaphocapitate ligament tightly constricts the vascular pedicle during fracture displacement.
. The primary vascular supply to the proximal pole is derived solely from the intra-articular branches of the anterior interosseous artery.

Correct Answer & Explanation

. The primary blood supply enters at the distal pole and provides retrograde perfusion to the proximal pole.

Explanation

The scaphoid is perfused primarily by the dorsal carpal branch of the radial artery, which enters distally and flows retrogradely toward the proximal pole. This tenuous retrograde blood supply leaves the proximal pole highly susceptible to ischemia and avascular necrosis following a fracture.

Question 472

Topic: Hand Trauma & Infection

A 35-year-old male presents with a severely infected third metacarpophalangeal (MCP) joint four days after a bar altercation where he punched another patron in the mouth. Intraoperative cultures grow Eikenella corrodens. Which of the following best describes the antibiotic susceptibility and microbiological profile of this organism?

. It is an anaerobic Gram-positive bacillus highly susceptible to clindamycin.
. It is a fastidious Gram-negative rod typically resistant to first-generation cephalosporins but susceptible to amoxicillin-clavulanate.
. It is a coagulase-negative staphylococcus requiring treatment with intravenous vancomycin.
. It is an aerobic Gram-negative coccus that is universally susceptible to simple penicillin but resistant to fluoroquinolones.
. It is a spore-forming rod that requires hyperbaric oxygen therapy and high-dose penicillin.

Correct Answer & Explanation

. It is a fastidious Gram-negative rod typically resistant to first-generation cephalosporins but susceptible to amoxicillin-clavulanate.

Explanation

Eikenella corrodens is a fastidious Gram-negative bacillus frequently isolated from clenched-fist 'fight bite' injuries. It is classically resistant to first-generation cephalosporins and clindamycin, but demonstrates excellent susceptibility to amoxicillin-clavulanate and penicillin.

Question 473

Topic: 7. Hand and Wrist

A 26-year-old avid golfer presents with chronic, deep, ulnar-sided volar wrist pain. He recently noted the inability to actively flex the distal interphalangeal joint of his small finger. Imaging confirms a chronic nonunion of the hook of the hamate. What is the pathomechanism of his new symptom?

. Direct compression of the motor branch of the median nerve at the wrist.
. Attrition and rupture of the flexor digitorum profundus (FDP) tendon of the small finger.
. Progressive avascular necrosis of the capitate extending to the hamate.
. Secondary extensor pollicis longus rupture due to altered carpal kinematics.
. Development of a scapholunate advanced collapse (SLAC) pattern.

Correct Answer & Explanation

. Attrition and rupture of the flexor digitorum profundus (FDP) tendon of the small finger.

Explanation

Hook of hamate fractures frequently occur from repetitive impact in racquet sports or golf. If left untreated, chronic friction against the irregular, nonunited fracture site can lead to tenosynovitis and subsequent attritional rupture of the adjacent FDP tendons, most commonly affecting the small finger.

Question 474

Topic: 7. Hand and Wrist

A 19-year-old male presents with a closed, isolated fracture of the fifth metacarpal neck (Boxer's fracture) following an altercation. He has no rotational deformity. What is the generally accepted maximum degree of volar angulation that can be treated non-operatively without significant functional impairment?

. 10 degrees
. 20 degrees
. 30 degrees
. 50 degrees
. 70 degrees

Correct Answer & Explanation

. 50 degrees

Explanation

Fractures of the fifth metacarpal neck can tolerate significant volar angulation due to the high compensatory mobility of the fourth and fifth carpometacarpal joints. Volar angulation up to 40 to 50 degrees is generally well tolerated and can be treated non-operatively.

Question 475

Topic: 7. Hand and Wrist
A 45-year-old manual laborer presents with progressive wrist pain and stiffness. Radiographs reveal an untreated scaphoid nonunion with advanced degenerative changes. According to the Scaphoid Nonunion Advanced Collapse (SNAC) classification, how is Stage II defined?
. Arthritis confined to the articulation between the radial styloid and the scaphoid.
. Arthritis extending to involve the scaphocapitate joint.
. Arthritis involving the radiolunate joint.
. Arthritis involving the entire carpus (pancarpal arthritis).
. Isolated lunocapitate arthritis with a normal radioscaphoid joint.

Correct Answer & Explanation

. Arthritis extending to involve the scaphocapitate joint.

Explanation

Scaphoid Nonunion Advanced Collapse (SNAC) progresses through predictable stages based on abnormal carpal kinematics. Stage I involves the radial styloid, Stage II progresses to the scaphocapitate joint, and Stage III involves the periscaphoid articulation, while characteristically sparing the radiolunate joint.

Question 476

Topic: 7. Hand and Wrist

A 30-year-old male sustains a Bennett fracture-dislocation of his dominant thumb. Which of the following best describes the primary deforming force responsible for proximal, dorsal, and radial displacement of the metacarpal shaft?

. Extensor carpi radialis longus
. Extensor carpi radialis brevis
. Abductor pollicis longus
. Adductor pollicis
. Flexor pollicis longus

Correct Answer & Explanation

. Abductor pollicis longus

Explanation

In a Bennett fracture, the small volar ulnar beak fragment is retained anatomically by the anterior oblique ligament. The larger metacarpal shaft is displaced proximally, dorsally, and radially primarily by the strong pull of the abductor pollicis longus (APL) tendon.

Question 477

Topic: Nerve & Tendon

If surgical intervention is warranted for the 42-year-old female with a stiff elbow, and she has a limitation of elbow flexion of 90 to 100 degrees, which of the following structures needs to be prophylactically addressed when performing an osteocapsular release?

. Ulnar nerve
. Anterior bundle of the MCL
. Posterior band of the MCL
. Fascia of the flexor pronator mass
. Medial intermuscular septum

Correct Answer & Explanation

. Ulnar nerve

Explanation

Correct Answer: AProphylactic treatment of the ulnar nerve (typically decompression or transposition) should be performed before an osteocapsular release in patients with significant elbow stiffness, especially if flexion is limited to 90-100 degrees or less. Anatomic studies have demonstrated that the cubital tunnel significantly decreases in size with elbow flexion greater than 90 degrees, leading to a corresponding increase in pressure on the ulnar nerve. After an osteocapsular release, the elbow's range of motion, particularly flexion, is expected to improve. This increased flexion can place the ulnar nerve under greater tension or compression, potentially exacerbating pre-existing neuropathy or inducing new symptoms. Given the patient's history of previous ulnar nerve surgery, the nerve is already vulnerable, making prophylactic management even more critical. The other structures listed are important for elbow stability or anatomy but are not typically prophylactically addressed in the same manner to prevent iatrogenic nerve compression from increased range of motion.

Question 478

Topic: 7. Hand and Wrist

A 68-year-old female presents after a fall on an outstretched hand (FOOSH) with a 'dinner fork' deformity of her right wrist. Radiographs confirm a dorsally displaced, dorsally angulated, comminuted distal radius fracture with an associated ulnar styloid fracture. Initial closed reduction under hematoma block achieves reasonable alignment, but post-reduction radiographs show a residual dorsal tilt of 15 degrees, radial shortening of 4 mm, and a positive ulnar variance of 2 mm. The fracture extends into the articular surface. Which of the following is the most significant indication for surgical intervention in this patient?

. Associated ulnar styloid fracture
. Age of the patient
. Comminution of the distal radius
. Persistent dorsal tilt and radial shortening after reduction
. Mechanism of injury (FOOSH)

Correct Answer & Explanation

. Persistent dorsal tilt and radial shortening after reduction

Explanation

Correct Answer: DThe most significant indication for surgical intervention in this scenario is the persistent dorsal tilt and radial shortening after reduction. While comminution, age, and ulnar styloid fracture are relevant factors, residual displacement parameters (dorsal tilt > 10 degrees, radial shortening > 3 mm) after initial attempts at closed reduction signify an unstable fracture that is likely to lose reduction, leading to malunion and functional impairment. These unstable parameters typically mandate surgical stabilization to restore and maintain anatomical alignment, preventing complications like pain, decreased range of motion, and post-traumatic arthritis. An ulnar styloid fracture alone is rarely an absolute indication unless it significantly contributes to DRUJ instability, which is not explicitly stated as the primary driver here. Comminution contributes to instability but theresultantunacceptable alignment after reduction is the direct surgical trigger.

Question 479

Topic: Wrist & Carpus

Regarding the surgical management of unstable Colles fractures with volar locking plates, which anatomical landmark is crucial to avoid hardware impingement on the flexor tendons and potential rupture?

. Lister's tubercle
. The pronator quadratus muscle insertion
. The volar watershed line
. The dorsal cortex of the distal radius
. The radial styloid process

Correct Answer & Explanation

. The volar watershed line

Explanation

Correct Answer: CThe volar watershed line is a critical anatomical landmark in volar plating of distal radius fractures. Plates placed distal to this line, or with screws protruding distally, risk irritation and rupture of the flexor tendons, particularly the flexor pollicis longus (FPL). The watershed line represents the ridge where the volar capsule and ligaments attach, marking the safe zone for plate placement proximally. Lister's tubercle is on the dorsal aspect, the pronator quadratus covers the plate proximally and protects tendons, but proper plate positioning relative to the articular surface, guided by the watershed line, is paramount for preventing distal tendon impingement.

Question 480

Topic: Wrist & Carpus

Which of the following is NOT typically considered a stable parameter after closed reduction of a Colles fracture?

. Radial inclination of 22 degrees
. Volar tilt of 5 degrees
. Radial length difference of 2 mm compared to the contralateral side
. Articular step-off of 3 mm
. Ulnar variance of 0 mm

Correct Answer & Explanation

. Articular step-off of 3 mm

Explanation

Correct Answer: DAn articular step-off of 3 mm is NOT considered a stable or acceptable parameter. Generally, an articular step-off or gap of >2 mm is considered unstable and an indication for surgical management, especially in active patients, due to the high risk of post-traumatic arthritis. Radial inclination of 22 degrees, volar tilt of 5 degrees (neutral to slight volar is acceptable for Colles), radial length difference of 2 mm (usually <3mm difference is acceptable), and ulnar variance of 0 mm (neutral) are all generally within acceptable post-reduction radiographic parameters for stable Colles fractures.

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