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Nerve & Tendon MCQs

Practice Set 37 of 53

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 721

Topic: Nerve & Tendon

Which of the following factors would most strongly favor consideration of primary arthrodesis of the DIP joint over FDP repair for a Jersey finger injury?

. Patient age of 25 years.
. Involvement of the ring finger.
. Acute Type II injury with good tendon quality.
. Chronic injury (>6 months) in a heavy manual laborer with severe DIP arthritis and high functional demands.
. Patient preference for early return to sports.

Correct Answer & Explanation

. Chronic injury (>6 months) in a heavy manual laborer with severe DIP arthritis and high functional demands.

Explanation

Primary arthrodesis of the DIP joint is considered for chronic flexor tendon injuries where tendon reconstruction is deemed unlikely to achieve good results, or in patients with pre-existing severe DIP joint arthritis, especially those with high demand for stable grip (like a heavy manual laborer). For a young, otherwise healthy patient with an acute injury, repair is almost always preferred. A chronic injury beyond 6 months, particularly if associated with significant joint degeneration and high functional demands for stability, can make arthrodesis a more predictable and functional outcome than a complex, multi-stage reconstruction. Early return to sports is not a reason for arthrodesis over repair.

Question 722

Topic: Nerve & Tendon

What is the primary concern if an FDP repair is performed with excessive tension?

. Delayed wound healing.
. Increased risk of infection.
. Development of a quadriga effect.
. Formation of a swan neck deformity.
. Inability to achieve full passive extension of the PIP joint.

Correct Answer & Explanation

. Development of a quadriga effect.

Explanation

Repairing the FDP tendon with excessive tension is a known cause of the quadriga effect. Because the FDP tendons of the medial four fingers share a common muscle belly, overtensioning one FDP tendon can restrict the ability of the adjacent, normally functioning FDP tendons to fully flex their respective DIP joints. This results in limited flexion of the uninjured fingers when the repaired finger attempts to flex fully. The other options are less directly and uniquely linked to excessive tension during FDP repair.

Question 723

Topic: Nerve & Tendon

A 60-year-old patient with an acute Jersey finger (Type I) and a history of poorly controlled diabetes presents for surgical repair. What is the most significant concern regarding his prognosis compared to a healthy individual?

. Increased risk of the 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

Poorly controlled diabetes significantly impairs wound healing due to microvascular disease, neuropathy, and compromised immune function. This leads to a substantially increased risk of surgical site infection, delayed tendon healing, and overall poorer outcomes in flexor tendon repair. While other complications can occur, impaired healing and infection risk are paramount concerns in diabetic patients. The other options are not specifically heightened by diabetes more than by general factors of tendon repair or intrinsic to the injury type.

Question 724

Topic: Nerve & Tendon

During examination of a suspected Jersey finger, how would you best differentiate an FDP rupture from a central slip rupture?

. An FDP rupture causes loss of DIP flexion, while a central slip rupture causes a boutonniere deformity (PIP flexion, DIP hyperextension).
. An FDP rupture involves the PIP joint, while a central slip rupture involves the DIP joint.
. An FDP rupture presents with a palpable gap in the palm, while a central slip rupture does not.
. An FDP rupture requires an MRI for diagnosis, while a central slip rupture is diagnosed clinically.
. An FDP rupture is acute, while a central slip rupture is always chronic.

Correct Answer & Explanation

. An FDP rupture causes loss of DIP flexion, while a central slip rupture causes a boutonniere deformity (PIP flexion, DIP hyperextension).

Explanation

The key differentiation lies in the affected joint and associated deformity. A complete FDP rupture leads to an inability to actively flex the DIP joint. A central slip rupture, by contrast, leads to disruption of the extensor mechanism at the PIP joint, eventually resulting in a boutonniere deformity (PIP joint flexion and compensatory DIP joint hyperextension). FDP involves the DIP, central slip involves PIP mechanics primarily. Palpable gaps are not universally present in FDP ruptures. Both can be diagnosed clinically, though imaging can confirm. Both can be acute.

Question 725

Topic: Nerve & Tendon

After surgical repair of a Type II Jersey finger, the patient develops a flexion contracture of the PIP joint. What is the most likely cause of this complication?

. Re-rupture of the FDP tendon.
. Adhesions between the FDS tendon and its sheath.
. Over-tightening of the F FDP repair causing a quadriga effect.
. Insufficient mobilization during the early post-operative period.
. Chronic inflammation of the extensor mechanism.

Correct Answer & Explanation

. Adhesions between the FDS tendon and its sheath.

Explanation

While the FDP was repaired, adhesions can occur between the FDS tendon and its sheath, or between the FDP and FDS, or the FDS to its own sheath. If the FDS tendon develops adhesions, it can limit PIP extension and lead to a flexion contracture of the PIP joint. Re-rupture of the FDP primarily affects DIP flexion. Quadriga effect limits flexion of adjacent fingers. Insufficient mobilization usually leads to global stiffness, but if specifically the FDS is adhered, it creates PIP flexion. Extensor inflammation would more likely cause an extensor lag or pain, not a contracture in flexion of PIP.

Question 726

Topic: Nerve & Tendon

A patient sustained a Jersey finger and is unable to undergo surgery for 5 weeks due to systemic illness. The injury is a Type I FDP avulsion of the ring finger. What is the most likely surgical approach to consider given this delayed presentation?

. Primary repair using a pull-out suture.
. FDP advancement, as the gap is still manageable.
. Staged tendon reconstruction with a silicone rod.
. Direct repair using bone anchors without any lengthening procedures.
. DIP joint arthrodesis as a primary procedure.

Correct Answer & Explanation

. Staged tendon reconstruction with a silicone rod.

Explanation

At 5 weeks, a Type I Jersey finger is already significantly delayed. The FDP tendon would have retracted considerably and undergone shortening and likely degenerative changes due to loss of blood supply. Primary repair with pull-out sutures or bone anchors would likely be impossible without excessive tension. FDP advancement is for smaller, acute gaps. Therefore, staged tendon reconstruction using a silicone rod to create a pseudosheath, followed by a tendon graft, becomes the most viable option to restore active flexion. DIP joint arthrodesis is a salvage procedure, typically considered after failed repairs or in very specific chronic cases.

Question 727

Topic: Nerve & Tendon

A patient presents with a chronic FDP rupture of the ring finger. He attempts to make a fist, and you observe active hyperextension of the DIP joint. This is known as:

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

Correct Answer & Explanation

. Lumbrical plus phenomenon.

Explanation

This is a classic description of the lumbrical plus phenomenon. In a chronic FDP rupture, the FDP tendon is slack or non-functional. When the patient attempts to flex the finger (activating the FDP muscle belly), the lumbrical muscle is pulled proximally, and its contraction (as it originates from the FDP tendon and inserts into the extensor mechanism) causes paradoxical extension of the DIP joint instead of flexion. This can be seen as active hyperextension of the DIP with attempted grip.

Question 728

Topic: Nerve & Tendon

What is the expected long-term outcome regarding grip strength following a successful FDP repair for a Type I Jersey finger in a young, compliant patient?

. Complete restoration of pre-injury grip strength within 3 months.
. Significant permanent reduction in grip strength, even with good recovery.
. Near-normal grip strength can be achieved, but DIP flexion strength may be slightly reduced.
. Grip strength will be entirely dependent on the FDS tendon, as FDP function is lost.
. Increased grip strength due to compensatory hypertrophy of other flexors.

Correct Answer & Explanation

. Near-normal grip strength can be achieved, but DIP flexion strength may be slightly reduced.

Explanation

Following a successful FDP repair in a young, compliant patient, near-normal grip strength can typically be achieved. However, isolated DIP flexion strength, and potentially endurance, may remain slightly reduced compared to the uninjured contralateral digit due to some scarring, stiffness, or slight tendon shortening. Complete restoration is optimistic, but significant permanent reduction is too pessimistic for a successful repair. The FDP is crucial for grip, not fully compensated by FDS. Increased grip strength is not expected.

Question 729

Topic: Nerve & Tendon

When evaluating a patient for a Jersey finger, which finding on physical examination most strongly suggests the FDS tendon is still functional?

. Inability to actively flex the DIP joint.
. Intact cascade of all fingers at rest.
. Ability to actively flex the PIP joint while holding adjacent fingers in extension.
. Pain with passive extension of the DIP joint.
. Palpable tendon in the distal palm.

Correct Answer & Explanation

. Ability to actively flex the PIP joint while holding adjacent fingers in extension.

Explanation

The Flexor Digitorum Superficialis (FDS) is the primary flexor of the PIP joint. The most definitive test for FDS function is to stabilize the patient's adjacent fingers in full extension (to inactivate the FDP of those fingers, which share a common muscle belly) and then ask the patient to actively flex the PIP joint of the finger being tested. If the PIP joint flexes against resistance, the FDS is functional. Inability to flex the DIP suggests FDP rupture. Intact cascade is an FDP sign. Pain with passive extension is non-specific. Palpable tendon doesn't confirm function.

Question 730

Topic: Nerve & Tendon

What is the most likely complication if the A2 pulley is inadvertently excised during FDP repair?

. Lumbrical plus phenomenon.
. Quadriga effect.
. Boutonniere deformity.
. Flexor tendon bowstringing.
. Increased risk of chronic pain.

Correct Answer & Explanation

. Flexor tendon bowstringing.

Explanation

The A2 pulley, along with the A4 pulley, is considered critical for maintaining the mechanical efficiency of the flexor tendons. Excision or rupture of the A2 pulley leads to 'bowstringing' of the flexor tendon, where the tendon lifts away from the bone during flexion, significantly reducing its mechanical advantage and causing a loss of grip strength and range of motion. Lumbrical plus and quadriga are related to tendon length/tension. Boutonniere involves the extensor mechanism. Chronic pain is a general complication, not specific to A2 excision.

Question 731

Topic: Nerve & Tendon

After ORIF of an adult Monteggia fracture, the patient complains of numbness in the small finger and medial half of the ring finger. What nerve injury should be suspected?

. Radial nerve
. Median nerve
. Posterior interosseous nerve
. Anterior interosseous nerve
. Ulnar nerve

Correct Answer & Explanation

. Ulnar nerve

Explanation

Numbness in the small finger and the medial half of the ring finger, along with weakness of intrinsic hand muscles (interossei, adductor pollicis), indicates an ulnar nerve injury. While PIN injury is most common with the Monteggia fracture itself, iatrogenic ulnar nerve injury can occur during surgical approaches to the medial or posterior elbow, or due to prolonged traction or compression during surgery. Assessment of nerve function is crucial both pre- and post-operatively.

Question 732

Topic: Nerve & Tendon

During surgical exposure for an olecranon fracture, the ulnar nerve is identified. What is the most appropriate management strategy if the nerve is found to be intact but compressed by surrounding hematoma or scar tissue, especially in a fracture requiring internal fixation?

. No intervention, close the wound
. Neurolysis in situ
. Anterior transposition of the ulnar nerve
. Posterior interosseous nerve release
. Immediate nerve graft

Correct Answer & Explanation

. Anterior transposition of the ulnar nerve

Explanation

If the ulnar nerve is found to be compressed or at high risk of post-operative compression/irritation (e.g., due to hardware placement or significant swelling, or pre-existing cubital tunnel syndrome), anterior transposition (C) is often performed prophylactically or therapeutically. This moves the nerve out of the cubital tunnel and into a less constrained anterior position, reducing the risk of neuropathy. Neurolysis in situ (B) may be considered for milder cases but is less definitive if significant risk factors for ongoing compression are present. No intervention (A) would be inappropriate if compression is present or anticipated. Posterior interosseous nerve release (D) is for radial nerve issues. Immediate nerve graft (E) is for transected nerves.

Question 733

Topic: Nerve & Tendon

During a posterior approach to the elbow for olecranon fracture fixation, the ulnar nerve is typically located in which anatomical relationship to the medial epicondyle?

. Anterior and lateral
. Posterior and lateral
. Anterior and medial
. Posterior and medial
. Directly over the olecranon tip

Correct Answer & Explanation

. Posterior and medial

Explanation

The ulnar nerve runs in the cubital tunnel, which is located posterior and medial (D) to the medial epicondyle of the humerus. This makes it vulnerable to injury during a posterior surgical approach to the olecranon, requiring careful identification and protection.

Question 734

Topic: Nerve & Tendon

What specific maneuver is critical to perform during the closure of a posterior approach for olecranon fracture fixation, especially if the ulnar nerve was exposed or transposed?

. Ensure full elbow extension
. Perform passive varus stress test
. Check for tension-free closure over the ulnar nerve
. Apply immediate full active flexion
. Tighten triceps repair aggressively

Correct Answer & Explanation

. Check for tension-free closure over the ulnar nerve

Explanation

Ensuring a tension-free closure over the ulnar nerve (C) is paramount to prevent post-operative nerve irritation or entrapment. If the nerve has been transposed, it must be placed in a bed of soft tissue and not directly beneath skin or fascia under tension. Aggressive tightening of the triceps repair (E) can cause undue tension. The other options are not directly related to ulnar nerve protection during closure.

Question 735

Topic: Nerve & Tendon

Besides early controlled range of motion, what other intra-operative technique is crucial to minimize post-operative elbow stiffness following olecranon fracture fixation?

. Prolonged tourniquet time
. Aggressive periosteal stripping
. Meticulous anatomical reduction of the articular surface
. Oversized hardware
. Routine prophylactic ulnar nerve transposition

Correct Answer & Explanation

. Meticulous anatomical reduction of the articular surface

Explanation

Meticulous anatomical reduction of the articular surface (C) is critical. A smooth, congruent joint surface minimizes friction, prevents abnormal contact stresses, and allows for smoother motion, significantly reducing the risk of post-traumatic arthritis and subsequent stiffness. Prolonged tourniquet time (A) and aggressive periosteal stripping (B) can increase tissue damage and lead to stiffness and heterotopic ossification. Oversized hardware (D) can itself be prominent and restrict motion. Routine prophylactic ulnar nerve transposition (E) is performed to prevent nerve symptoms, not primarily stiffness, although avoiding nerve irritation can facilitate rehabilitation.

Question 736

Topic: Nerve & Tendon
All of the following are potential contributing factors to elbow stiffness following an olecranon fracture EXCEPT:
. Prolonged immobilization
. Heterotopic ossification
. Complex intra-articular comminution
. Aggressive early active range of motion within pain limits
. Ulnar nerve entrapment

Correct Answer & Explanation

. Aggressive early active range of motion within pain limits

Explanation

Aggressive early active range of motion within pain limits is actually a preventative measure against stiffness, as controlled motion helps maintain joint mobility and cartilage health. Therefore, it is not a contributing factor to stiffness. Prolonged immobilization, heterotopic ossification, and complex intra-articular comminution are all well-known causes of elbow stiffness. Ulnar nerve entrapment can cause pain and limit participation in rehabilitation, thereby indirectly contributing to stiffness.

Question 737

Topic: Nerve & Tendon

Which peripheral nerve is most commonly injured in association with olecranon fractures or during their surgical repair?

. Radial nerve
. Median nerve
. Ulnar nerve
. Musculocutaneous nerve
. Anterior interosseous nerve

Correct Answer & Explanation

. Ulnar nerve

Explanation

The ulnar nerve (C) is located in the cubital tunnel posterior to the medial epicondyle, making it highly susceptible to injury during olecranon fractures (due to direct trauma, displacement of fragments, or hematoma) and during surgical approaches (due to retraction, direct injury, or hardware impingement). It is by far the most commonly involved nerve in this setting.

Question 738

Topic: Nerve & Tendon

Which factor makes the posterior aspect of the elbow particularly prone to hardware prominence and subsequent irritation after olecranon fracture fixation?

. High vascularity of the olecranon
. Lack of significant muscle or subcutaneous tissue coverage
. Presence of the ulnar nerve in the cubital tunnel
. Frequent flexion and extension movements of the elbow
. High incidence of infection

Correct Answer & Explanation

. Lack of significant muscle or subcutaneous tissue coverage

Explanation

The posterior aspect of the elbow (over the olecranon) has very little subcutaneous tissue or muscle coverage, making it particularly susceptible to hardware prominence and irritation (B). Even well-placed hardware can be felt directly under the skin, leading to pain, bursitis, or skin breakdown, often necessitating removal once the fracture has healed. While frequent movement (D) can exacerbate symptoms, the lack of soft tissue is the primary anatomical reason for prominence.

Question 739

Topic: Nerve & Tendon

Which of the following nerves is most commonly injured with a supracondylar humerus fracture in a child?

. Radial nerve
. Ulnar nerve
. Median nerve
. Anterior interosseous nerve (AIN)
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve (AIN)

Explanation

The anterior interosseous nerve (AIN), a motor branch of the median nerve, is the most commonly injured nerve in supracondylar humerus fractures, particularly in extension-type injuries. AIN injury manifests as inability to make an 'OK' sign (flexion of IP joint of thumb and DIP joint of index finger). While the median nerve itself and the radial nerve can be injured, the AIN is specifically highlighted due to its vulnerability in this common pediatric fracture.

Question 740

Topic: Nerve & Tendon

A 35-year-old carpenter sustains a deep laceration to his proximal volar forearm. After wound closure, he is unable to make an 'OK' sign, demonstrating an extended distal interphalangeal joint of the index finger and an extended interphalangeal joint of the thumb. Which of the following muscles is most likely spared in this specific isolated nerve injury?

. Flexor pollicis longus
. Flexor digitorum profundus to the index finger
. Flexor digitorum profundus to the middle finger
. Pronator quadratus
. Flexor carpi radialis

Correct Answer & Explanation

. Flexor carpi radialis

Explanation

The patient has an Anterior Interosseous Nerve (AIN) palsy, characterized by the inability to form the 'OK' sign due to paralysis of the Flexor Pollicis Longus (FPL) and the Flexor Digitorum Profundus (FDP) to the index (and often middle) finger. The AIN also innervates the Pronator Quadratus. The Flexor Carpi Radialis (FCR) is innervated by the main branch of the median nerve before it gives off the AIN, and is therefore spared in an isolated AIN injury.

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