This practice set contains high-yield board review questions covering key concepts in Nerve & Tendon. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 141
Topic: Nerve & Tendon
Which of the following anatomical structures is MOST critical for providing blood supply to the flexor digitorum profundus (FDP) tendon in the distal finger, particularly relevant in Type I Jersey finger injuries?
Correct Answer & Explanation
. Vincula tendinum.
Explanation
Correct Answer: CThe vincula tendinum are mesotendinous structures that connect the flexor tendons to the phalanges and provide the primary blood supply to the tendons within the flexor sheath. In a Type I Jersey finger, the FDP tendon avulses distal to the vincula longa and retracts into the palm, often stripping it of its vincula and thus its blood supply, leading to a high risk of tendon necrosis. The A2 pulley is a critical mechanical structure but not primarily a source of blood supply to the tendon itself. The flexor sheath provides an environment, not the primary blood supply. Annular ligaments are the pulleys. Lumbrical muscles have their own blood supply but do not supply the FDP tendon directly.
Question 142
Topic: Nerve & Tendon
A patient undergoes FDP repair for a Jersey finger. The post-operative protocol involves early active motion. What is the primary rationale behind initiating early active motion protocols for flexor tendon repairs?
Correct Answer & Explanation
. To prevent adhesion formation and improve tendon gliding.
Explanation
Correct Answer: DThe primary rationale for early active motion protocols after flexor tendon repair is to promote tendon gliding and prevent the formation of restrictive adhesions within the flexor sheath. Controlled motion helps to maintain the gliding surface between the tendon and the surrounding tissues, which is crucial for achieving a good functional outcome and full range of motion. While it may indirectly help with swelling and muscle atrophy, its main goal is to optimize tendon healing and prevent adhesions, which is a major cause of post-operative stiffness.
Question 143
Topic: Nerve & Tendon
During the primary repair of a Zone II flexor tendon laceration, a surgeon elects to use a multi-strand core suture technique. Which of the following factors is most critical in minimizing gap formation at the repair site during early active rehabilitation?
Correct Answer & Explanation
. The number of core suture strands crossing the repair site.
Explanation
The biomechanical strength and resistance to gap formation in a flexor tendon repair are most directly correlated with the number of core suture strands crossing the repair site and adequate core purchase length. Epitendinous sutures further increase repair strength and smooth the gliding surface.
Question 144
Topic: Nerve & Tendon
A 30-year-old rugby player presents with an inability to actively flex the distal interphalangeal (DIP) joint of his ring finger. MRI demonstrates a flexor digitorum profundus (FDP) avulsion retracted completely into the palm. Within what maximum timeframe should this specific injury ideally be surgically repaired to prevent permanent tendon retraction and necrosis?
Correct Answer & Explanation
. 7 to 10 days
Explanation
This describes a Leddy and Packer Type I FDP avulsion (Jersey finger), where the tendon retracts into the palm, disrupting both the long and short vincula. It requires surgical repair within 7-10 days before the tendon undergoes contracture and ischemic necrosis.
Question 145
Topic: Nerve & Tendon
A 22-year-old rugby player grabs an opponent's jersey and feels a pop in his ring finger. He cannot actively flex the distal interphalangeal (DIP) joint. Imaging shows no fracture, and the flexor digitorum profundus (FDP) tendon is palpable in the palm. What is the optimal timing and treatment?
Correct Answer & Explanation
. Surgical repair within 7-10 days to prevent tendon retraction and myostatic contracture
Explanation
This is a Type 1 Jersey finger (FDP retracted into the palm), compromising its vascular supply from the vincula. It requires early surgical repair within 7-10 days to prevent permanent myostatic contracture and tendon necrosis.
Question 146
Topic: Nerve & Tendon
A patient develops a Boutonniere deformity 4 weeks after suffering a volar PIP joint dislocation. Which of the following best describes the underlying pathomechanics of this deformity?
Correct Answer & Explanation
. Rupture of the central slip with volar subluxation of the lateral bands
Explanation
A Boutonniere deformity is characterized by PIP flexion and DIP extension. It is caused by rupture or attenuation of the central slip, allowing the lateral bands to subluxate volarly to the PIP joint axis of rotation, acting as PIP flexors and DIP extensors.
Question 147
Topic: Nerve & Tendon
A 62-year-old patient is undergoing tension band wiring for a displaced olecranon fracture. During the posterior approach to the elbow, the surgical team must be particularly vigilant about identifying and protecting a specific neurovascular structure that is intimately associated with the medial aspect of the olecranon. Which of the following structures is at the highest risk of iatrogenic injury during this procedure?
Correct Answer & Explanation
. Ulnar nerve
Explanation
Correct Answer: DThe case clearly identifies the 'Ulnar Nerve' as the most critical neurovascular structure at risk during olecranon surgery. It courses posterior to the medial epicondyle, within the cubital tunnel, and is intimately associated with the medial aspect of the olecranon. Meticulous identification and protection or, if indicated, prophylactic decompression or anterior transposition, are paramount to prevent iatrogenic injury.Option A (Median nerve) and Option E (Brachial artery) are incorrectbecause these structures are located anterior to the elbow joint and are generally not at risk with a posterior approach to the olecranon.Option B (Radial nerve) is incorrectas the radial nerve and its branches (including the PIN) are located more laterally and anteriorly, primarily at risk during lateral or anterior approaches to the elbow, not a direct posterior approach to the olecranon.Option C (Posterior interosseous nerve - PIN) is incorrect. While a branch of the radial nerve, it is not directly in the surgical field for a posterior olecranon approach and is not the most vulnerable structure in this specific context.
Question 148
Topic: Nerve & Tendon
During posterior plating of an olecranon fracture, a surgeon utilizes an approach that elevates the flexor carpi ulnaris off the medial aspect of the ulna. Which nerve is at greatest direct risk of iatrogenic injury during this specific portion of the exposure?
Correct Answer & Explanation
. Ulnar nerve
Explanation
The ulnar nerve courses directly posterior to the medial epicondyle and rests adjacent to the medial aspect of the proximal ulna deep to the flexor carpi ulnaris. Medial dissection or misplaced retractors during olecranon plating place it at high risk.
Question 149
Topic: Nerve & Tendon
A 72-year-old patient is undergoing a total shoulder arthroplasty in the beach chair position. During the procedure, the anesthesia team reports a significant drop in blood pressure. The surgeon is concerned about potential complications related to patient positioning. Which of the following neurological complications is a rare but serious risk associated with the beach chair position, particularly with sustained hypotension?
Correct Answer & Explanation
. D. Posterior ischemic optic neuropathy (PION)
Explanation
Correct Answer: DWhile the case study mentions 'Risk of Cerebral Hypoperfusion' and 'Neck and Head Positioning: Requires careful padding and stabilization to prevent nerve palsy (e.g., brachial plexus, ulnar nerve) or pressure injuries,' it does not explicitly list Posterior Ischemic Optic Neuropathy (PION). However, PION is a well-recognized, albeit rare, and devastating complication associated with the beach chair position, especially in the context of prolonged surgery, significant blood loss, and sustained hypotension. It results from inadequate perfusion to the optic nerve. The question asks for a 'rare but serious risk associated with the beach chair position, particularly with sustained hypotension.' Ulnar nerve palsy (A) and brachial plexus neuropraxia (B) are more commonly associated with direct pressure or stretch from improper limb/neck positioning, not primarily hypotension. Spinal cord injury (C) is extremely rare and typically related to direct trauma or pre-existing spinal conditions, not the beach chair position itself. Sciatic nerve palsy (E) is a lower extremity nerve injury, not typically associated with shoulder surgery in the beach chair position.
Question 150
Topic: Nerve & Tendon
When performing a single-incision anterior approach for distal biceps tendon repair, blind placement of deep retractors laterally over the radial neck places which of the following structures at highest risk of iatrogenic injury?
Correct Answer & Explanation
. Posterior interosseous nerve
Explanation
While the LABC nerve is at risk superficially, deep retractors placed blindly around the radial neck during a single-incision biceps repair put the posterior interosseous nerve (PIN) at significant risk.
Question 151
Topic: Nerve & Tendon
When performing a Zone II flexor tendon repair, which of the following biomechanical factors most significantly increases the tensile strength of the repair?
Correct Answer & Explanation
. Number of core suture strands crossing the repair site
Explanation
The ultimate tensile strength of a flexor tendon repair is directly proportional to the number of core suture strands crossing the repair site. A 4-strand or 6-strand repair allows for safe early active motion protocols.
Question 152
Topic: Nerve & Tendon
A 22-year-old rugby player aggressively grabs an opponent's jersey and feels a pop in his right ring finger. He is unable to actively flex the distal interphalangeal (DIP) joint. On examination, a tender mass is palpable in the proximal palm. According to the Leddy and Packer classification, what is the recommended timeframe for surgical repair?
Correct Answer & Explanation
. Within 7-10 days
Explanation
This is a Type I flexor digitorum profundus (FDP) avulsion (Jersey finger) where the tendon retracts into the palm, compromising its blood supply from the vincula. Early surgical repair within 7-10 days is required to prevent myostatic contracture and tendon necrosis.
Question 153
Topic: Nerve & Tendon
A 40-year-old mechanic presents with an inability to make an "OK" sign, instead forming a flat pinch between his thumb and index finger. Sensation in the hand is completely normal. Compression of which nerve is responsible for this deficit?
Correct Answer & Explanation
. Anterior interosseous nerve
Explanation
The anterior interosseous nerve (AIN) innervates the flexor pollicis longus (FPL), flexor digitorum profundus (FDP) to the index/middle fingers, and pronator quadratus. AIN syndrome causes a pure motor deficit, preventing flexion of the IP joint of the thumb and DIP of the index finger.
Question 154
Topic: Nerve & Tendon
A 50-year-old patient is 3 weeks post-operative from a surgical repair of a soft tissue mallet finger with transarticular K-wire fixation. He is currently in Phase 1 of his rehabilitation protocol. Which of the following instructions is most critical for the patient to adhere to during this phase?
Correct Answer & Explanation
. Ensure continuous immobilization of the DIP joint in full extension.
Explanation
Correct Answer: CThe 'Post-Operative Rehabilitation Protocols' section, under 'Phase 1: Immobilization (Weeks 0-6)', states: 'The primary goal of this phase is to protect the surgically repaired terminal extensor tendon, allowing for initial healing... Crucial Principle: Absolutely no active or passive DIP joint flexion is permitted. The patient must be meticulously educated on this, particularly for activities of daily living.'Incorrect Options:Begin gentle active DIP flexion exercises to prevent stiffness:This is strictly prohibited in Phase 1 to protect the healing tendon. Active DIP flexion is only gradually introduced in Phase 3.Perform light resistive exercises for DIP extension:Strengthening exercises are part of Phase 3 (Weeks 12+), not Phase 1.Remove the K-wire daily for cleaning and reinsertion:K-wires are sterilely placed and remain in situ until removal by the surgeon, typically at 6 weeks. Daily removal would introduce infection risk and compromise fixation.Initiate scar massage over the surgical incision:Scar management is initiated in Phase 2 (Weeks 6-12) 'once the wound is well-healed', not in Phase 1 when the wound is still fresh.
Question 155
Topic: Nerve & Tendon
A 35-year-old patient presents with a chronic soft tissue mallet finger of 8 months duration. He has a 40-degree extensor lag at the DIP joint and has developed a fixed hyperextension deformity of the PIP joint, consistent with a swan neck deformity. He failed a prolonged course of non-operative management. Which of the following statements regarding the management of his swan neck deformity is most accurate?
Correct Answer & Explanation
. Addressing the mallet deformity is paramount, and the fixed swan neck may require additional procedures like PIP volar plate tenodesis or intrinsic release.
Explanation
Correct Answer: CThe case discusses 'Swan Neck Deformity' as a complication, stating: 'This secondary deformity results from an imbalance in the extensor mechanism, with volar plate laxity at the PIP joint and overactivity of the central slip, leading to PIP hyperextension and compensatory DIP flexion. It can be a consequence of untreated or failed mallet finger.' For 'Fixed Deformity', it notes: 'Often requires complex reconstruction, including PIP volar plate tenodesis, intrinsic release, or PIP arthrodesis in severe, recalcitrant cases. Addressing the underlying mallet deformity (if not already done) is paramount.'Incorrect Options:The swan neck deformity will spontaneously resolve once the mallet finger is surgically repaired:While flexible swan neck deformities may improve, a 'fixed' deformity, as described, typically requires additional intervention beyond just mallet repair.PIP flexion splinting alone will be sufficient to correct a fixed swan neck deformity:PIP flexion splinting is indicated for 'flexible' deformities. A 'fixed' deformity implies structural changes that require more aggressive management, potentially surgical.The swan neck deformity is a contraindication to surgical repair of the mallet finger:A fixed swan neck deformity is listed as an 'Operative Indication' for mallet finger, often requiring a combined approach, not a contraindication.The primary cause of the PIP hyperextension is laxity of the central slip, which should be shortened:The case states the swan neck results from 'volar plate laxity at the PIP joint and overactivity of the central slip'. Shortening the central slip would exacerbate PIP hyperextension, as the central slip extends the PIP joint.
Question 156
Topic: Nerve & Tendon
A 22-year-old athlete presents with an acute soft tissue mallet finger of the ring finger. He has full passive DIP extension and an active extensor lag of 35 degrees. He is highly motivated and compliant. Based on the case, what is the most appropriate initial management strategy and its critical success factor?
Correct Answer & Explanation
. Continuous immobilization of the DIP joint in full extension for 6-8 weeks, with the critical factor being patient compliance.
Explanation
Correct Answer: BThe 'Indications & Contraindications' section, under 'Non-Operative Indications', states: 'The vast majority of acute soft tissue mallet injuries (Doyle Type I) are successfully managed non-operatively. The core principle is continuous immobilization of the DIP joint in full extension or slight hyperextension (0-10 degrees) for a prolonged period, typically 6 to 8 weeks, followed by a gradual weaning phase. The PIP joint should be left free to allow full range of motion.' It also lists 'Patient Compliance' as a key factor. The 'Summary of Key Literature / Guidelines' reinforces this: 'continuous immobilization of the DIP joint in extension (or slight hyperextension) for 6-8 weeks... remains the gold standard for acute soft tissue injuries. Studies... underscore the high success rates (typically 80-90%) with proper splinting and patient compliance. The critical factor is continuous wear.'Incorrect Options:Immediate surgical repair with K-wire fixation, with the critical factor being early active DIP motion:Surgical repair is generally reserved for failed non-operative management or specific complex cases, not acute, compliant patients. Early active DIP motion is contraindicated post-surgery.Dynamic splinting of the DIP joint to gradually restore extension, with the critical factor being aggressive strengthening:Dynamic splinting is not the initial treatment for acute mallet finger. Continuous static immobilization is preferred. Aggressive strengthening is for later phases.PIP joint immobilization to prevent swan neck deformity, with the critical factor being early return to sport:The PIP joint should be left free to allow full range of motion during DIP splinting. Early return to sport is not the critical factor for healing.Oral anti-inflammatory medications and rest, with the critical factor being pain control:While pain control is important, this alone does not address the mechanical disruption of the tendon. Immobilization is the primary treatment.
Question 157
Topic: Nerve & Tendon
A 65-year-old patient undergoes surgical repair for a chronic soft tissue mallet finger. Six months post-operatively, despite adherence to the rehabilitation protocol, he presents with a persistent 20-degree extensor lag at the DIP joint and significant loss of DIP flexion, limiting his ability to grasp small objects. Which of the following complications is most likely contributing to his current functional deficit, and what is a potential salvage strategy for the persistent extensor lag?
Correct Answer & Explanation
. Extensor lag / Re-rupture; Salvage with revision surgery (e.g., repeat repair, tenodesis, or DIP fusion).
Explanation
Correct Answer: CThe 'Complications & Management' table lists 'Extensor Lag / Re-rupture' as 'Most common (5-20%), higher in chronic cases'. The explanation further states: 'Recurrent extensor lag is the most frequent reason for dissatisfaction post-surgery... For persistent, functionally significant lag, revision surgery may be considered. Options include repeat direct repair, tendon advancement (if proximal tissue allows), tenodesis (using a portion of the lateral band or a small palmaris longus graft), or, in cases of severe, irreparable damage with significant functional impairment, DIP joint arthrodesis (fusion) in a functional position.'Incorrect Options:Infection; Salvage with immediate K-wire removal and antibiotics:While infection is a complication, the primary issue described is persistent extensor lag and stiffness, not signs of active infection. K-wires are typically removed at 6 weeks, not 6 months.Nail deformity; Salvage with nail bed revision:Nail deformity is often cosmetic and does not typically cause a 20-degree extensor lag or significant loss of DIP flexion.Hypersensitivity/CRPS; Salvage with sympathetic blocks:CRPS is rare and presents with a constellation of symptoms (pain, swelling, skin changes) beyond just extensor lag and stiffness.Skin necrosis; Salvage with local flap coverage:Skin necrosis is an acute wound healing complication, not a chronic issue presenting 6 months post-op with extensor lag and stiffness.
Question 158
Topic: Nerve & Tendon
A 24-year-old athlete presents with an acute soft-tissue mallet deformity of his long finger after jamming it during a basketball game. Radiographs are negative for any fracture. What is the gold standard initial management for this injury?
Correct Answer & Explanation
. Continuous DIP joint extension splinting for 6 to 8 weeks
Explanation
The primary treatment for an acute soft-tissue mallet finger is continuous, uninterrupted extension splinting of the DIP joint for 6 to 8 weeks. The PIP joint should be left free to allow active range of motion and prevent stiffness.
Question 159
Topic: Nerve & Tendon
A 55-year-old woman presents with a chronic, untreated mallet finger injury of the small digit sustained 6 months ago. She has now developed a secondary deformity characterized by DIP joint flexion and PIP joint hyperextension. What is the primary pathophysiological mechanism causing the hyperextension at the PIP joint?
Correct Answer & Explanation
. Proximal retraction of the extensor mechanism and lateral bands
Explanation
An untreated mallet finger can lead to a swan neck deformity due to the proximal retraction of the extensor mechanism. This proximal migration increases the extension force transmitted through the central slip at the PIP joint, leading to hyperextension.
Question 160
Topic: Nerve & Tendon
A 60-year-old man receives an injection of collagenase clostridium histolyticum for a prominent central cord causing an MCP joint contracture. When performing this injection, careful technique is required to prevent a severe complication associated with incorrect placement. Injecting the medication too deep poses the greatest risk of damage to which structure?
Correct Answer & Explanation
. Flexor digitorum superficialis tendon
Explanation
Collagenase injections carry a risk of flexor tendon rupture if injected incorrectly. The needle must remain within the diseased fascial cord to avoid enzymatic degradation of the underlying flexor tendons or pulleys.
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