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7. Hand and Wrist MCQs

Practice Set 27 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 521

Topic: Nerve & Tendon

A 40-year-old patient presents with a chronic FDP rupture of the ring finger (6 months post-injury). When attempting to make a full fist, the patient exhibits paradoxical hyperextension of the DIP joint and hyperextension of the PIP joint of the affected finger. This specific clinical presentation is known as:

. Quadriga effect.
. Boutonniere deformity.
. Swan neck deformity.
. Lumbrical plus phenomenon.
. Mallet finger.

Correct Answer & Explanation

. Lumbrical plus phenomenon.

Explanation

Correct Answer: DRationale:The described clinical presentation is characteristic of the lumbrical plus phenomenon.Option D (Lumbrical plus phenomenon)is correct. This occurs when the FDP tendon is ruptured, slack, or excessively shortened (e.g., due to overtensioned repair or chronic retraction). When the patient attempts to flex the finger (activating the FDP muscle belly), the lumbrical muscle, which originates from the FDP tendon and inserts into the extensor mechanism, is pulled proximally. This tension on the lumbrical causes it to act as an extensor of the DIP joint and can also contribute to PIP joint hyperextension, resulting in paradoxical DIP extension (or hyperextension) when the patient tries to make a fist.Option A (Quadriga effect)is incorrect. The quadriga effect refers to the restriction of flexion in adjacent, uninjured fingers due to overtensioning or shortening of one FDP tendon, as they share a common muscle belly. It does not involve paradoxical DIP extension.Option B (Boutonniere deformity)is incorrect. A boutonniere deformity is characterized by PIP joint flexion and DIP joint hyperextension, typically due to a central slip rupture of the extensor mechanism.Option C (Swan neck deformity)is incorrect. A swan neck deformity is characterized by PIP joint hyperextension and DIP joint flexion, often seen in conditions like rheumatoid arthritis or due to FDS laxity.Option E (Mallet finger)is incorrect. A mallet finger is a flexion deformity of the DIP joint due to rupture or avulsion of the extensor tendon at its insertion on the distal phalanx.

Question 522

Topic: 7. Hand and Wrist

A 55-year-old manual laborer presents 4 months after sustaining a Jersey finger injury (Type I) to his long finger. He has no active DIP flexion and significant tendon retraction into the palm. Direct primary repair is deemed impossible due to the chronic nature and extensive tendon shortening. What is the most appropriate surgical management strategy for this patient?

. Primary FDP advancement with a bone anchor.
. Non-operative management with intensive hand therapy.
. Immediate DIP joint arthrodesis.
. Staged tendon reconstruction using a silicone rod followed by tendon grafting.
. Flexor digitorum superficialis (FDS) tenodesis to the distal phalanx.

Correct Answer & Explanation

. Staged tendon reconstruction using a silicone rod followed by tendon grafting.

Explanation

Correct Answer: DRationale:For chronic FDP ruptures (typically beyond 3-4 weeks, and certainly at 4 months) where significant tendon retraction and shortening have occurred, direct primary repair or FDP advancement (which is suitable for acute injuries with small gaps, usually <1 cm) is generally not feasible without excessive tension. Excessive tension leads to complications like the quadriga effect or re-rupture.Option D (Staged tendon reconstruction using a silicone rod followed by tendon grafting)is correct. This is the gold standard for managing chronic FDP ruptures with significant tendon loss or retraction. In the first stage, a silicone rod (Hunter rod) is inserted into the flexor sheath to create a smooth, gliding pseudosheath. After several months, in a second stage, the silicone rod is removed, and an autogenous tendon graft (e.g., palmaris longus, plantaris) is threaded through the pseudosheath and attached to the distal phalanx and the FDP muscle belly, restoring active flexion.Option A (Primary FDP advancement with a bone anchor)is incorrect. FDP advancement is for acute injuries with minimal retraction. At 4 months, the tendon would be too retracted and shortened for this technique without excessive tension.Option B (Non-operative management with intensive hand therapy)is incorrect. Non-operative management will not restore active DIP flexion in a complete, chronic FDP rupture.Option C (Immediate DIP joint arthrodesis)is incorrect. While arthrodesis is a salvage procedure for failed repairs or in specific cases (e.g., severe arthritis, very low functional demand), it is generally not the first-line treatment for a chronic FDP rupture, especially in a manual laborer who might benefit from some active motion.Option E (Flexor digitorum superficialis (FDS) tenodesis to the distal phalanx)is incorrect. FDS tenodesis can provide some active DIP flexion or prevent hyperextension, but it typically offers less robust motion and strength compared to a staged FDP reconstruction. It might be considered for older patients with lower functional demands or as a simpler alternative, but staged reconstruction is generally preferred for restoring more complete function in a manual laborer.

Question 523

Topic: Nerve & Tendon

A surgeon performs a primary FDP repair for a Type I Jersey finger. Post-operatively, the patient complains that when attempting to make a full fist with the repaired finger, the adjacent middle and small fingers are unable to fully flex at their DIP joints. What is the most likely cause of this specific complication?

. Adhesions within the flexor sheath of the repaired finger.
. Re-rupture of the FDP tendon in the repaired finger.
. Excessive tension on the repaired FDP tendon.
. Lumbrical plus phenomenon in the repaired finger.
. Insufficient strength of the FDS tendons in the adjacent fingers.

Correct Answer & Explanation

. Excessive tension on the repaired FDP tendon.

Explanation

Correct Answer: CRationale:The described complication is a classic presentation of the quadriga effect.Option C (Excessive tension on the repaired FDP tendon)is correct. The quadriga effect occurs because the FDP tendons of the middle, ring, and small fingers share a common muscle belly (or are closely intertwined proximally). If one FDP tendon (in this case, the repaired ring finger FDP) is repaired with excessive tension or advanced too much, it restricts the full excursion of the entire FDP muscle group. When the patient attempts to flex the repaired finger, the overtensioned FDP prevents the adjacent, otherwise healthy FDP tendons from fully flexing their respective DIP joints.Option A (Adhesions within the flexor sheath of the repaired finger)is incorrect. Adhesions would primarily limit the range of motion (both flexion and extension) of therepairedfinger itself, not specifically restrict flexion in theadjacentfingers.Option B (Re-rupture of the FDP tendon in the repaired finger)is incorrect. Re-rupture would result in a complete loss of active DIP flexion in therepairedfinger, not restricted flexion in adjacent fingers.Option D (Lumbrical plus phenomenon in the repaired finger)is incorrect. Lumbrical plus phenomenon involves paradoxical DIP extension of therepairedfinger when attempting to flex, not restricted flexion in adjacent fingers.Option E (Insufficient strength of the FDS tendons in the adjacent fingers)is incorrect. The FDS tendons primarily flex the PIP joints. The complaint is about DIP joint flexion, which is controlled by the FDP.

Question 524

Topic: Nerve & Tendon

A 22-year-old athlete sustains a Type I Jersey finger injury. The FDP tendon is found to be retracted into the palm. What specific anatomical structures are most critical for providing blood supply to the FDP tendon in the distal finger, and why is their disruption a major concern in this injury type?

. The A2 and A4 pulleys; they provide direct arterial branches.
. The flexor sheath; it contains a rich vascular plexus.
. The vincula tendinum; they are mesotendinous structures supplying the tendon.
. The lumbrical muscles; they directly vascularize the FDP.
. The digital neurovascular bundles; they run adjacent to the tendon.

Correct Answer & Explanation

. The vincula tendinum; they are mesotendinous structures supplying the tendon.

Explanation

Correct Answer: CRationale:The blood supply to the flexor tendons within the fibro-osseous sheath is crucial for their viability and healing. This supply comes primarily from specific mesotendinous structures.Option C (The vincula tendinum; they are mesotendinous structures supplying the tendon)is correct. The vincula tendinum (vincula longa and vincula brevia) are delicate mesotendinous folds that connect the flexor tendons to the phalanges and the flexor sheath. They carry small arteries that provide the primary blood supply to the FDP and FDS tendons as they pass through the flexor sheath. In a Type I Jersey finger, the FDP tendon avulses without a bony fragment and retracts significantly into the palm. This retraction often strips the tendon of its vincula, leading to a loss of its intrinsic blood supply and placing it at high risk of necrosis, which is why urgent repair is critical.Option A (The A2 and A4 pulleys; they provide direct arterial branches)is incorrect. The A2 and A4 pulleys are crucial mechanical structures that prevent bowstringing and maintain mechanical advantage, but they are not the primary source of blood supply to the tendon substance itself.Option B (The flexor sheath; it contains a rich vascular plexus)is incorrect. While the flexor sheath provides a low-friction environment and contains some vascularity, the direct supply to the tendon comes via the vincula, not directly from the sheath itself as a primary source.Option D (The lumbrical muscles; they directly vascularize the FDP)is incorrect. The lumbrical muscles originate from the FDP tendons but do not provide the primary blood supply to the FDP tendon itself along its course in the finger.Option E (The digital neurovascular bundles; they run adjacent to the tendon)is incorrect. The digital neurovascular bundles run on the sides of the fingers and supply the skin, nerves, and bone, but they do not directly vascularize the FDP tendon within its sheath.

Question 525

Topic: Nerve & Tendon

A 19-year-old patient presents with an acute Jersey finger of the ring finger. Surgical repair is planned. Which of the following surgical incisions is most commonly preferred for accessing the flexor tendons in the finger and why?

. A straight longitudinal volar incision; it provides direct access.
. A midaxial incision along the side of the finger; it avoids neurovascular structures.
. A transverse volar incision at the level of the PIP joint; it minimizes scarring.
. A zigzag incision (Brunner's incision) over the volar aspect; it prevents flexion contracture.
. A dorsal approach with splitting of the extensor mechanism; it offers better visualization.

Correct Answer & Explanation

. A zigzag incision (Brunner's incision) over the volar aspect; it prevents flexion contracture.

Explanation

Correct Answer: DRationale:The choice of surgical incision for flexor tendon repair in the finger is critical to ensure adequate exposure while minimizing complications, particularly flexion contractures.Option D (A zigzag incision (Brunner's incision) over the volar aspect; it prevents flexion contracture)is correct. The Brunner's zigzag incision is the most commonly preferred and safest approach for accessing the flexor tendons and sheath in the finger. This incision provides excellent exposure of the underlying structures while avoiding the creation of a long, linear scar that would be prone to contracting across the flexion creases, thereby preventing a flexion contracture.Option A (A straight longitudinal volar incision; it provides direct access)is incorrect. While it provides direct access, a straight longitudinal volar incision is contraindicated in the finger due to the very high risk of developing a severe and debilitating flexion contracture as the scar matures.Option B (A midaxial incision along the side of the finger; it avoids neurovascular structures)is incorrect. A midaxial incision is typically used for bony procedures, joint access, or accessing the neurovascular bundles, but it does not provide optimal direct access to the flexor tendons within their sheath. It also runs close to the neurovascular bundles.Option C (A transverse volar incision at the level of the PIP joint; it minimizes scarring)is incorrect. While transverse incisions can minimize scarring, a single transverse incision would provide very limited exposure for a flexor tendon repair that often spans multiple zones.Option E (A dorsal approach with splitting of the extensor mechanism; it offers better visualization)is incorrect. A dorsal approach is used for extensor tendon injuries, dorsal bony injuries, or joint fusions. It does not provide access to the flexor tendons, which are on the volar aspect of the finger.

Question 526

Topic: Nerve & Tendon

A 16-year-old patient undergoes FDP repair for a Type I Jersey finger of the small finger. The surgeon notes that the small finger FDP tendon appears smaller in diameter and somewhat more friable than typically seen in other digits. What is the most likely long-term implication of this observation, specifically for the small finger?

. Increased risk of quadriga effect.
. Higher incidence of lumbrical plus phenomenon.
. Greater propensity for persistent stiffness and poorer functional outcomes.
. Reduced risk of re-rupture due to less tension.
. Faster healing time due to smaller size.

Correct Answer & Explanation

. Greater propensity for persistent stiffness and poorer functional outcomes.

Explanation

Correct Answer: CRationale:While FDP avulsion injuries can occur in any digit, the small finger is often cited as having unique challenges and potentially poorer outcomes.Option C (Greater propensity for persistent stiffness and poorer functional outcomes)is correct. The FDP tendon of the small finger is often anatomically smaller in diameter and can be inherently weaker or more friable compared to the FDP tendons of the other digits. This smaller caliber and potentially poorer tissue quality can make surgical repair more challenging, lead to less robust repairs, and contribute to a higher rate of persistent stiffness, less overall range of motion, and generally poorer functional outcomes (e.g., grip strength, dexterity) even with technically successful repairs and diligent rehabilitation.Option A (Increased risk of quadriga effect)is incorrect. The quadriga effect is related to excessive tension in the repair, not specifically to the small finger's inherent tendon quality.Option B (Higher incidence of lumbrical plus phenomenon)is incorrect. Lumbrical plus is related to FDP slackness or overtensioning, not specifically to the small finger's intrinsic tendon quality.Option D (Reduced risk of re-rupture due to less tension)is incorrect. A smaller, weaker tendon would likely have anincreasedrisk of re-rupture if not repaired adequately, not a reduced risk.Option E (Faster healing time due to smaller size)is incorrect. Tendon healing is a biological process that is not significantly accelerated by smaller tendon size; rather, smaller size can make the repair more delicate.

Question 527

Topic: Nerve & Tendon

A 35-year-old patient presents with a suspected Jersey finger. On physical examination, you stabilize the patient's adjacent fingers (long and small) in full extension and ask them to actively flex the PIP joint of the ring finger. The patient is able to flex the PIP joint against resistance. What information does this specific maneuver provide?

. It confirms a complete FDP rupture.
. It rules out a central slip rupture.
. It assesses the integrity and function of the FDS tendon.
. It indicates an intact lumbrical muscle.
. It suggests a partial FDP tear.

Correct Answer & Explanation

. It assesses the integrity and function of the FDS tendon.

Explanation

Correct Answer: CRationale:This maneuver is a classic test to isolate and assess the function of the Flexor Digitorum Superficialis (FDS) tendon.Option C (It assesses the integrity and function of the FDS tendon)is correct. The FDS tendons for the middle, ring, and small fingers share a common muscle belly (or are closely related proximally), as do the FDP tendons. To isolate the FDS of a specific finger, the adjacent fingers must be held in full extension. This maneuver prevents the FDP of the tested finger from acting (as the FDP of the adjacent fingers would also be activated, causing unwanted flexion). If the patient can then actively flex the PIP joint of the tested finger against resistance, it confirms the integrity and function of the FDS tendon for that digit.Option A (It confirms a complete FDP rupture)is incorrect. This test assesses FDS function, not FDP rupture. FDP rupture is assessed by the inability to actively flex the DIP joint.Option B (It rules out a central slip rupture)is incorrect. A central slip rupture affects the extensor mechanism at the PIP joint, leading to a boutonniere deformity. This test is for flexor function.Option D (It indicates an intact lumbrical muscle)is incorrect. While the lumbricals are intrinsic muscles, this test specifically isolates FDS function.Option E (It suggests a partial FDP tear)is incorrect. This test does not directly assess the FDP tendon.

Question 528

Topic: 7. Hand and Wrist
A 48-year-old patient undergoes surgical repair of a Type III Jersey finger, where a large bony avulsion fragment was reattached to the distal phalanx. Four weeks post-operatively, X-rays show no signs of healing at the bone-to-bone interface, and the patient reports persistent pain and tenderness over the distal phalanx. What is the most likely complication in this scenario?
. Re-rupture of the FDP tendon.
. Lumbrical plus phenomenon.
. Non-union of the bony fragment.
. Quadriga effect.
. Adhesions within the flexor sheath.

Correct Answer & Explanation

. Non-union of the bony fragment.

Explanation

A Type III Jersey finger involves a bony avulsion fragment from the distal phalanx. When this fragment is reattached, the healing of the bone-to-bone interface is crucial for a successful outcome. The scenario describes a lack of radiographic healing at the bone-to-bone interface and persistent pain/tenderness, which are classic signs of a non-union of the reattached bony fragment. This is a specific complication associated with avulsion fractures where bone healing is required.

Question 529

Topic: Nerve & Tendon

A 65-year-old patient with a history of poorly controlled diabetes and peripheral neuropathy sustains an acute Type I Jersey finger. He is scheduled for surgical repair. Compared to a healthy, non-diabetic patient, what is the most significant increased risk factor for a poor outcome in this patient?

. Increased risk of quadriga effect.
. Higher likelihood of lumbrical plus phenomenon.
. Significantly impaired wound healing and increased infection risk.
. Inability to tolerate early active motion protocols.
. Greater chance of associated nerve injury.

Correct Answer & Explanation

. Significantly impaired wound healing and increased infection risk.

Explanation

Correct Answer: CRationale:Systemic comorbidities can significantly impact the prognosis and outcome of flexor tendon repairs.Option C (Significantly impaired wound healing and increased infection risk)is correct. Poorly controlled diabetes, especially when accompanied by peripheral neuropathy, is a major risk factor for complications in surgical procedures, including flexor tendon repair. Diabetes impairs wound healing due to microvascular disease (reduced blood flow), neuropathy (impaired sensation and trophic changes), and compromised immune function. This leads to a substantially increased risk of surgical site infection, delayed tendon healing, and overall poorer functional outcomes.Option A (Increased risk of quadriga effect)is incorrect. The quadriga effect is primarily related to surgical technique (excessive tension in the repair), not directly to diabetes.Option B (Higher likelihood of lumbrical plus phenomenon)is incorrect. Lumbrical plus phenomenon is related to FDP tendon length/tension, not directly to diabetes.Option D (Inability to tolerate early active motion protocols)is incorrect. While neuropathy might affect sensation and compliance, the primary issue is biological healing, not necessarily tolerance of motion protocols, which are carefully controlled.Option E (Greater chance of associated nerve injury)is incorrect. While peripheral neuropathy is present, it doesn't inherently increase the chance of anassociatednerve injury from the initial trauma or during surgery more than in a healthy individual. The concern is more about the healing process.

Question 530

Topic: 7. Hand and Wrist

A 22-year-old male presents with radial-sided wrist pain after a fall onto an outstretched hand. Imaging confirms a displaced proximal pole fracture of the scaphoid. Operative fixation is planned. Which of the following surgical approaches is most appropriate, and why?

. Volar approach to preserve the dorsal carpal branch of the radial artery
. Dorsal approach to preserve the volar radiocarpal ligaments and optimize visualization of the proximal fragment
. Percutaneous volar approach using a headless compression screw
. Arthroscopically assisted volar approach to evaluate interosseous ligaments
. Medial approach through the floor of the carpal tunnel

Correct Answer & Explanation

. Dorsal approach to preserve the volar radiocarpal ligaments and optimize visualization of the proximal fragment

Explanation

Proximal pole scaphoid fractures are best approached dorsally. This approach avoids injury to the vital volar radiocarpal ligaments and provides direct, in-line visualization and access for screw trajectory into the small proximal pole.

Question 531

Topic: Wrist & Carpus

A 25-year-old male sustains a closed volar Barton's fracture of the distal radius after a motorcycle accident. Which of the following is the most appropriate surgical treatment strategy to restore articular congruity and prevent displacement?

. Closed reduction and percutaneous pinning
. Spanning external fixation alone
. Volar buttress plating
. Dorsal spanning plate
. Fragment-specific dorsal plating

Correct Answer & Explanation

. Volar buttress plating

Explanation

A volar Barton's fracture is a volar shear fracture of the distal radius with radiocarpal subluxation. Volar buttress plating is the gold standard as it mechanically blocks the volar displacement of the articular fragment and carpus.

Question 532

Topic: 7. Hand and Wrist

A 30-year-old carpenter sustains a clean laceration to the volar aspect of his index finger at the level of the proximal phalanx, resulting in inability to flex the DIP and PIP joints. Following primary repair of both the FDS and FDP tendons, which postoperative rehabilitation protocol yields the best functional outcome?

. Strict immobilization for 6 weeks
. Early active motion protocols (e.g., Belfast or modified Duran)
. Dynamic extension splinting with static flexion
. Immediate passive flexion and active extension only
. Immobilization for 3 weeks followed by aggressive passive stretching

Correct Answer & Explanation

. Early active motion protocols (e.g., Belfast or modified Duran)

Explanation

Zone II flexor tendon repairs benefit significantly from early active motion protocols. This approach reduces tendon adhesions, improves tendon excursion, and maximizes functional outcomes compared to strict immobilization or purely passive protocols.

Question 533

Topic: Wrist & Carpus
A 45-year-old man presents with chronic wrist pain. Radiographs reveal a scaphoid waist nonunion with advanced radioscaphoid arthritis, but the midcarpal joint is spared. What is the correct classification for this pattern of arthritis?
. SNAC Stage I
. SNAC Stage II
. SNAC Stage III
. SLAC Stage I
. SLAC Stage II

Correct Answer & Explanation

. SNAC Stage II

Explanation

Scaphoid Nonunion Advanced Collapse (SNAC) Stage II involves arthritis extending to the entire radioscaphoid joint. Stage I involves only the radial styloid, while Stage III involves the capitolunate joint.

Question 534

Topic: Hand Trauma & Infection

A patient presents with a swollen, erythematous index finger 3 days after a puncture wound. Which of Kanavel's cardinal signs of flexor tenosynovitis is generally considered the most sensitive and earliest finding?

. Fusiform swelling of the digit
. Pain with passive extension of the digit
. Flexed resting posture of the digit
. Tenderness along the flexor tendon sheath
. Erythema tracking up the forearm

Correct Answer & Explanation

. Pain with passive extension of the digit

Explanation

Pain with passive extension of the digit is typically the earliest and most sensitive of Kanavel's four cardinal signs for purulent flexor tenosynovitis.

Question 535

Topic: 7. Hand and Wrist

A patient sustained a Monteggia fracture-dislocation that was treated surgically. Postoperatively, he is unable to actively extend his thumb and digits at the MCP joints, but he can extend his wrist with radial deviation. Sensation in the hand is completely normal. What is the most likely diagnosis?

. High radial nerve palsy
. Anterior interosseous nerve syndrome
. Ulnar nerve neurapraxia
. Posterior interosseous nerve (PIN) palsy
. Median nerve injury

Correct Answer & Explanation

. Posterior interosseous nerve (PIN) palsy

Explanation

PIN palsy presents with loss of digit and thumb extension, but wrist extension is preserved (though radially deviated) due to an intact ECRL, which is innervated by the radial nerve proper proximal to the PIN branch. Sensation remains intact because the superficial sensory branch of the radial nerve is spared.

Question 536

Topic: 7. Hand and Wrist

A 40-year-old mechanic sustains a fingertip amputation of the middle finger resulting in a volar-oblique defect with exposed distal phalanx bone. Which of the following local flap options is most appropriate for coverage of this specific defect?

. V-Y advancement (Atasoy) flap
. Cross-finger flap
. Moberg volar advancement flap
. Thenar flap
. Reverse radial forearm flap

Correct Answer & Explanation

. Cross-finger flap

Explanation

A volar-oblique fingertip defect with exposed bone is best covered by a cross-finger flap, which provides stable volar soft tissue. A V-Y advancement flap is indicated for transverse or dorsal-oblique defects, while the Moberg flap is strictly for the thumb.

Question 537

Topic: Nerve & Tendon

A 21-year-old rugby player presents 2 days after violently grabbing an opponent's jersey. He cannot actively flex the DIP joint of his ring finger. MRI confirms the FDP tendon is retracted completely into the palm. According to the Leddy-Packer classification, what is the optimal timing for surgical repair of this Type I injury?

. Within 24 hours
. Within 7 to 10 days
. Within 3 to 4 weeks
. After 3 months with a two-stage tendon reconstruction
. Immediate non-operative management

Correct Answer & Explanation

. Within 7 to 10 days

Explanation

A Leddy-Packer Type I "jersey finger" involves the FDP tendon retracting into the palm, severing all vincular blood supply. It must be repaired within 7 to 10 days before the tendon retracts permanently and undergoes myostatic contracture.

Question 538

Topic: Hand Trauma & Infection

A 28-year-old woman injured her thumb while skiing, resulting in a "Gamekeeper's thumb" (ulnar collateral ligament tear). Physical exam reveals an endpoint on valgus stress in extension, but no endpoint with 30 degrees of flexion, and a palpable mass at the ulnar base of the thumb MCP. What anatomical structure is blocking healing of the ligament, necessitating surgical repair?

. Extensor pollicis longus tendon
. Adductor pollicis aponeurosis
. Abductor pollicis brevis tendon
. Flexor pollicis brevis tendon
. Volar plate

Correct Answer & Explanation

. Adductor pollicis aponeurosis

Explanation

A Stener lesion occurs when the torn ends of the ulnar collateral ligament of the thumb are separated by the adductor pollicis aponeurosis. This interposition prevents primary healing and is an absolute indication for surgical repair.

Question 539

Topic: 7. Hand and Wrist

When performing an open carpal tunnel release, the surgeon must be mindful of the variable anatomy of the recurrent motor branch of the median nerve. Which anatomic variant places the recurrent motor branch at the greatest risk for iatrogenic transection during release of the transverse carpal ligament?

. Extraligamentous with recurrent course
. Subligamentous with ulnar course
. Transligamentous course
. Pre-ligamentous branching from the ulnar nerve
. High division of the median nerve

Correct Answer & Explanation

. Transligamentous course

Explanation

The transligamentous variant occurs in approximately 20% of cases, where the recurrent motor branch pieces directly through the transverse carpal ligament. This anatomy places the nerve at significant risk during standard carpal tunnel release if the ligament is divided blindly.

Question 540

Topic: 7. Hand and Wrist

A 65-year-old woman sustained a minimally displaced distal radius fracture treated non-operatively in a cast. Six weeks later, she presents to the clinic unable to actively extend the interphalangeal joint of her thumb. What is the most likely etiology of her new deficit?

. Median nerve compression in the carpal tunnel
. Attrition and rupture of the Extensor Pollicis Longus (EPL) tendon
. Nonunion of the distal radius fracture
. Rupture of the Extensor Pollicis Brevis (EPB) tendon
. Adhesive capsulitis of the CMC joint

Correct Answer & Explanation

. Attrition and rupture of the Extensor Pollicis Longus (EPL) tendon

Explanation

EPL tendon rupture is a known complication following non-displaced or minimally displaced distal radius fractures. It occurs due to vascular compromise or mechanical attrition of the tendon as it passes around Lister's tubercle.

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