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9. Shoulder and Elbow MCQs

Practice Set 147 of 197

This practice set contains high-yield board review questions covering key concepts in 9. Shoulder and Elbow. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2921

Topic: 9. Shoulder and Elbow

What is the recommended period of immobilization after an isolated, stable simple elbow dislocation (without associated fractures) in an adult, prior to initiating early controlled range of motion?

. No immobilization; immediate range of motion.
. 1-3 days (e.g., sling for comfort).
. 2-3 weeks.
. 4-6 weeks.
. 6-8 weeks.

Correct Answer & Explanation

. 1-3 days (e.g., sling for comfort).

Explanation

For a simple, stable elbow dislocation after successful reduction and confirmation of stability, the current recommendation is for brief immobilization (1-3 days, often just for comfort) followed by early, protected range of motion, often in a hinged brace to guide motion within the stable arc. This approach aims to prevent stiffness, which is a major complication of prolonged immobilization. Therefore, 1-3 days (Option B) is the most appropriate. Options C, D, and E represent prolonged immobilization that would increase stiffness. Option A, 'no immobilization; immediate range of motion,' might be too aggressive immediately post-reduction, as some initial soft tissue healing is beneficial. The sling for comfort for a few days fits the '1-3 days' option.

Question 2922

Topic: Elbow & Forearm

During closed reduction of a posterior elbow dislocation, one should avoid excessive force and hyperflexion primarily to prevent which complication?

. Ulnar nerve entrapment.
. Iatrogenic fracture of the coronoid or distal humerus.
. Radial head subluxation.
. Medial collateral ligament avulsion.
. Heterotopic ossification.

Correct Answer & Explanation

. Iatrogenic fracture of the coronoid or distal humerus.

Explanation

Excessive force, particularly with hyperflexion, during closed reduction can lead to iatrogenic fracture, most commonly of the coronoid process or distal humerus. It can also increase the risk of neurovascular injury. While ulnar nerve entrapment (Option A) can occur, it is often due to the initial injury or specific reduction maneuvers. Radial head subluxation (Option C) is a different pattern of instability. Medial collateral ligament avulsion (Option D) is more related to valgus stress. Heterotopic ossification (Option E) is a long-term complication, not an acute risk of reduction itself.

Question 2923

Topic: 9. Shoulder and Elbow

What is the primary indication for surgical intervention in an acute, simple posterior elbow dislocation?

. Patient's desire for a faster return to sport.
. Chronic ulnar neuropathy.
. Irreducibility by closed means.
. Presence of a small, stable coronoid tip fracture.
. More than 5 degrees of elbow extension deficit after reduction.

Correct Answer & Explanation

. Irreducibility by closed means.

Explanation

The primary indication for surgical intervention in an acute, simple posterior elbow dislocation is irreducibility by closed means. This typically implies soft tissue interposition (e.g., medial epicondyle, brachialis muscle) or a significant bony block. A patient's desire for faster return to sport (Option A) is not a medical indication for acute surgery on a simple dislocation. Chronic ulnar neuropathy (Option B) is a pre-existing condition, not an acute indication unless it worsens significantly. A small, stable coronoid tip fracture (Option D) typically doesn't require surgical fixation. More than 5 degrees of extension deficit (Option E) is a common finding and managed with physiotherapy, not acute surgery.

Question 2924

Topic: Elbow & Forearm

In a patient with a terrible triad injury, after repairing the lateral ulnar collateral ligament (LUCL) and addressing the coronoid fracture, what is the MOST important consideration for managing a repairable radial head fracture?

. Excise the radial head to prevent stiffness.
. Perform immediate arthrodesis of the elbow.
. Achieve stable internal fixation with anatomical reduction to maintain radial length and joint congruity.
. Immobilize the elbow in full extension for 6 weeks.
. Replace the radial head with a metallic implant regardless of reparability.

Correct Answer & Explanation

. Achieve stable internal fixation with anatomical reduction to maintain radial length and joint congruity.

Explanation

For a repairable radial head fracture in a terrible triad injury, the MOST important consideration is to achieve stable internal fixation with anatomical reduction to maintain radial length and joint congruity. This contributes significantly to overall elbow stability by providing a buttress to the capitellum and helping to restore forearm mechanics. Excising the radial head (Option A) is contraindicated as it destabilizes the elbow. Arthrodesis (Option B) is a salvage procedure. Immobilization (Option D) leads to stiffness and may not maintain reduction. Replacing the radial head (Option E) is only for non-reparable fractures.

Question 2925

Topic: 9. Shoulder and Elbow

Which direction of elbow dislocation is the MOST common?

. Anterior.
. Posterior.
. Medial.
. Lateral.
. Divergent.

Correct Answer & Explanation

. Posterior.

Explanation

Posterior (or posterolateral) dislocation is by far the most common direction of elbow dislocation, accounting for over 90% of cases. The mechanism is typically a fall on an outstretched hand with the elbow slightly flexed and forearm supinated, causing an axial load and valgus/posterolateral stress. Anterior, medial, lateral, and divergent dislocations are rare.

Question 2926

Topic: 9. Shoulder and Elbow
A 55-year-old male sustains a posterior elbow dislocation. After successful closed reduction, radiographs show a small coronoid tip fracture (Regan and Morrey Type I) and no other associated injuries. On examination, the elbow is stable throughout a full range of motion. What is the appropriate initial immobilization for this patient?
. Dynamic hinged elbow brace, allowing immediate full ROM.
. Long arm cast in 90 degrees flexion and pronation for 3 weeks.
. Sling for comfort for 3-5 days, then early protected range of motion.
. Sugar-tong splint in full extension for 2 weeks.
. Elbow extension block brace (limiting extension to 30 degrees) for 6 weeks.

Correct Answer & Explanation

. Sling for comfort for 3-5 days, then early protected range of motion.

Explanation

For a simple, stable posterior elbow dislocation, even with a small, stable coronoid tip fracture, the modern approach emphasizes early protected range of motion to prevent stiffness. A sling for comfort for a few days (e.g., 3-5 days) followed by early, protected range of motion within the stable arc is the most appropriate management.

Question 2927

Topic: 9. Shoulder and Elbow

What is the primary goal of early range of motion exercises following a simple, stable elbow dislocation?

. To prevent heterotopic ossification.
. To strengthen the surrounding musculature.
. To prevent elbow stiffness.
. To reduce the risk of ulnar nerve compression.
. To allow for rapid return to sport.

Correct Answer & Explanation

. To prevent elbow stiffness.

Explanation

The primary goal of early range of motion (ROM) exercises following a simple, stable elbow dislocation is to prevent elbow stiffness, which is a very common and debilitating complication of prolonged immobilization. While strengthening (Option B) and return to sport (Option E) are later goals, preventing stiffness (Option C) is the immediate priority for rehabilitation. While early motion may indirectly help reduce HO (Option A) compared to prolonged immobilization, preventing stiffness is the direct and most significant benefit. Ulnar nerve compression (Option D) is an acute complication, not primarily addressed by early ROM.

Question 2928

Topic: 9. Shoulder and Elbow

In a patient presenting with a posterior elbow dislocation, which artery is MOST at risk of injury?

. Radial artery.
. Ulnar artery.
. Brachial artery.
. Anterior interosseous artery.
. Deep brachial artery.

Correct Answer & Explanation

. Brachial artery.

Explanation

The brachial artery (Option C) is the most commonly injured artery in association with elbow dislocations. It lies anterior to the elbow joint and is tethered at the cubital fossa, making it vulnerable to stretch or tear during hyperextension and dislocation. While radial and ulnar arteries (Options A and B) are distal branches, the brachial artery is the main vessel across the joint. The anterior interosseous (Option D) and deep brachial (Option E) arteries are less commonly directly affected.

Question 2929

Topic: 9. Shoulder and Elbow

A 40-year-old active female sustains a posterior elbow dislocation. After successful closed reduction, she complains of persistent weakness and tingling in her little finger and half of her ring finger. What is the MOST appropriate initial management?

. Immediate surgical exploration and ulnar nerve transposition.
. Re-reduction of the elbow to relieve potential nerve entrapment.
. Elbow immobilization in flexion to decompress the nerve.
. Observation and protected range of motion with a hinged elbow brace, monitoring neurological recovery.
. High-dose oral corticosteroids.

Correct Answer & Explanation

. Observation and protected range of motion with a hinged elbow brace, monitoring neurological recovery.

Explanation

The symptoms described are consistent with ulnar nerve palsy. In the setting of an acute elbow dislocation, ulnar nerve injuries are common. If the nerve palsy is incomplete (tingling, weakness rather than complete paralysis) and the elbow is reduced, the initial management is typically observation and protected range of motion with a hinged elbow brace, closely monitoring neurological recovery (Option D). Most nerve palsies associated with dislocations are neuropraxias and resolve spontaneously. Immediate surgical exploration and transposition (Option A) is reserved for complete palsy, worsening symptoms, or chronic non-resolving symptoms. Re-reduction (Option B) is unnecessary if the elbow is already reduced. Immobilization (Option C) may worsen stiffness. Corticosteroids (Option E) are not indicated.

Question 2930

Topic: 9. Shoulder and Elbow

When assessing the stability of a reduced elbow dislocation, what is the 'arc of stability'?

. The range of motion from 0 to 30 degrees of extension.
. The range of motion where the elbow is stable to valgus and varus stress.
. The range of motion where the elbow is stable and free from apprehension or subluxation.
. The maximum flexion achieved without pain.
. The range of motion from 90 to 120 degrees of flexion.

Correct Answer & Explanation

. The range of motion where the elbow is stable and free from apprehension or subluxation.

Explanation

The 'arc of stability' refers to the range of motion through which the elbow remains concentrically reduced and stable (without apprehension or subluxation) when applying varus, valgus, and rotational stresses. It is a critical assessment after reduction to guide post-operative immobilization and rehabilitation protocols. While stability to valgus/varus stress (Option B) is part of it, the 'arc of stability' is a broader concept that includes overall stability through motion, making Option C the most comprehensive and accurate definition.

Question 2931

Topic: Elbow & Forearm

A patient presents with a history of recurrent elbow dislocations. What is the MOST likely underlying anatomical deficiency?

. Weakness of the biceps brachii muscle.
. Chronic insufficiency of the medial ulnar collateral ligament (MUCL).
. Chronic insufficiency of the lateral ulnar collateral ligament (LUCL).
. Persistent radial head subluxation.
. Heterotopic ossification around the olecranon fossa.

Correct Answer & Explanation

. Chronic insufficiency of the lateral ulnar collateral ligament (LUCL).

Explanation

Recurrent elbow dislocations are most commonly associated with chronic insufficiency of the lateral ulnar collateral ligament (LUCL), leading to recurrent posterolateral rotatory instability (PLRI). This is because the LUCL is the primary restraint to posterolateral displacement of the ulna and radius from the humerus. While MUCL insufficiency (Option B) causes valgus instability, it is less commonly the primary cause of recurrent dislocation itself compared to LUCL. Muscle weakness (Option A), radial head subluxation (Option D), or HO (Option E) are not the primary underlying anatomical deficiencies for recurrent dislocations.

Question 2932

Topic: 9. Shoulder and Elbow

Which complication is LEAST likely to occur following a simple elbow dislocation that is promptly reduced and managed appropriately?

. Elbow stiffness.
. Recurrent dislocation.
. Ulnar nerve neuropathy.
. Heterotopic ossification.
. Post-traumatic arthritis.

Correct Answer & Explanation

. Recurrent dislocation.

Explanation

Recurrent dislocation (Option B) is relatively uncommon after a simple elbow dislocation that is promptly reduced and managed appropriately (i.e., early motion within the stable arc). Elbow stiffness (Option A) is very common, even with good management. Ulnar nerve neuropathy (Option C) can occur acutely. Heterotopic ossification (Option D) and post-traumatic arthritis (Option E) are also potential long-term complications, though less frequent in simple dislocations than in complex ones. The key here is 'LEAST likely'.

Question 2933

Topic: 9. Shoulder and Elbow
In the case of a complex elbow dislocation involving a displaced coronoid fracture (Regan and Morrey Type II or III) and radial head fracture, which factor is MOST critical for achieving long-term elbow stability and good functional outcome?
. Early physiotherapy with passive range of motion.
. Achieving stable fixation of the coronoid process to restore the anterior buttress.
. Using a hinged elbow brace for 12 weeks post-operatively.
. Complete excision of the radial head.
. Strict immobilization for 8 weeks.

Correct Answer & Explanation

. Achieving stable fixation of the coronoid process to restore the anterior buttress.

Explanation

For complex elbow dislocations with coronoid fractures, achieving stable fixation of the coronoid process is MOST critical for restoring the anterior buttress effect, which prevents posterior subluxation of the ulna and contributes significantly to overall elbow stability.

Question 2934

Topic: 9. Shoulder and Elbow

What is the key difference between a 'simple' and a 'complex' elbow dislocation?

. Simple dislocations involve only posterior displacement, while complex dislocations involve other directions.
. Simple dislocations are seen in adults, complex dislocations in children.
. Simple dislocations have no associated fractures, while complex dislocations have associated fractures.
. Simple dislocations are reducible by closed means, complex dislocations require open reduction.
. Simple dislocations have no neurovascular compromise, complex dislocations always do.

Correct Answer & Explanation

. Simple dislocations have no associated fractures, while complex dislocations have associated fractures.

Explanation

The key distinguishing factor between a simple and a complex elbow dislocation is the presence of associated fractures. Simple dislocations involve only soft tissue injury (ligaments, capsule) and no associated fractures. Complex dislocations include associated fractures, such as radial head, coronoid process, or olecranon fractures, which significantly impact stability and management. Direction of dislocation (Option A) is not the defining difference. Age (Option B) is not a defining factor. While complex dislocations often require open reduction (Option D), and simple ones are usually reducible, this is a consequence, not the primary definition. Neurovascular compromise (Option E) can occur in either.

Question 2935

Topic: Elbow & Forearm

A patient sustains a posterior elbow dislocation. During assessment, the physician notes an inability to fully supinate the forearm and a click with pronation. This may indicate an injury to which structure?

. Medial ulnar collateral ligament.
. Lateral ulnar collateral ligament (LUCL) complex.
. Annular ligament.
. Radial head.
. Brachialis muscle.

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL) complex.

Explanation

The inability to fully supinate and a click with pronation after an elbow dislocation may indicate an injury to the lateral ulnar collateral ligament (LUCL) complex, specifically the lateral collateral ligament. This pattern suggests posterolateral rotatory instability (PLRI) where the radial head and ulna pivot or subluxate posterolaterally. The LUCL is the primary restraint to PLRI. Medial ulnar collateral ligament (Option A) injury causes valgus instability. Annular ligament (Option C) injury leads to radial head subluxation but less commonly this specific pronation/supination click. Radial head (Option D) is bony, and brachialis muscle (Option E) is soft tissue but less specifically related to this click.

Question 2936

Topic: Elbow & Forearm

What is the typical management approach for an acutely dislocated radial head with an intact ulna (isolated radial head dislocation)?

. Closed reduction followed by long arm cast in supination.
. Open reduction and internal fixation of the radial head.
. Radial head excision to prevent re-dislocation.
. Closed reduction followed by long arm cast in pronation.
. No specific treatment, as it is a stable injury.

Correct Answer & Explanation

. Closed reduction followed by long arm cast in supination.

Explanation

Isolated radial head dislocations (without an ulnar fracture, often referred to as a congenital or developmental issue, or potentially an acute traumatic entity in specific scenarios) are rare in adults and usually unstable after reduction. However, a pure traumatic isolated radial head dislocation is extremely rare. More commonly, radial head dislocations are associated with ulnar shaft fractures (Monteggia lesion). If it's apureisolated radial head dislocation, closed reduction is attempted, but stability is a major issue. For traumatic isolated radial head dislocation without associated ulnar fracture, which implies tearing of the annular ligament, stabilization of the radial head via closed reduction followed by a long arm cast insupinationis typically attempted to reduce stress on the annular ligament and the interosseous membrane. However, if irreducible or unstable, surgical repair of the annular ligament might be needed. Option A: Closed reduction followed by long arm cast insupinationis chosen to maintain reduction by tightening the interosseous membrane. Option D, pronation, would loosen it. This assumes an acute traumatic injury. If it is a chronic or congenital dislocation, management is different. This question is tricky given the 'isolated' aspect. Let's re-evaluate. Most 'isolated' radial head dislocations are congenital. Traumatic isolated radial head dislocation implies annular ligament rupture, and closed reduction with supination is the typical initial treatment to attempt to re-engage the radial head and allow annular ligament healing. If irreducible or unstable, then surgery for annular ligament repair is indicated. Radial head excision (Option C) is destabilizing. Therefore, closed reduction and immobilization in supination is the most appropriateinitialmanagement for an acute traumatic isolated radial head dislocation.

Question 2937

Topic: 9. Shoulder and Elbow

Which of the following describes the 'pivot shift test' for the elbow?

. Applying valgus stress to the elbow in full extension.
. Applying varus stress to the elbow in 90 degrees of flexion.
. Applying axial compression and pronation while moving the elbow from extension to flexion with valgus stress.
. Assessing stability to flexion-extension by applying anterior-posterior force to the radial head.
. Testing for ulnar nerve integrity by tapping the cubital tunnel.

Correct Answer & Explanation

. Applying axial compression and pronation while moving the elbow from extension to flexion with valgus stress.

Explanation

The elbow pivot shift test is performed by applying axial compression and pronation while moving the elbow from extension into flexion, with an added valgus moment (Option C). A positive test indicates posterolateral rotatory instability, with the radius and ulna subluxating posterolaterally in extension and reducing with a 'clunk' as the elbow is flexed. This test specifically evaluates the integrity of the lateral ulnar collateral ligament (LUCL) complex. Option A tests valgus stability, Option B tests varus stability, Option D assesses humeroradial or humeroulnar translation, and Option E is Tinel's sign for ulnar nerve.

Question 2938

Topic: 9. Shoulder and Elbow

A patient undergoes surgical repair of a complex elbow dislocation. Post-operatively, a hinged external fixator is applied. What is the primary advantage of using a hinged external fixator in this scenario?

. Allows for immediate full weight-bearing on the arm.
. Provides static stability while permitting controlled, pain-free range of motion.
. Completely prevents heterotopic ossification.
. Eliminates the need for any internal fixation of associated fractures.
. Facilitates nerve regeneration.

Correct Answer & Explanation

. Provides static stability while permitting controlled, pain-free range of motion.

Explanation

A hinged external fixator provides static stability to the elbow joint, particularly in cases of severe instability (e.g., following complex ligamentous repairs or highly comminuted fractures), while simultaneously permitting controlled, early range of motion (Option B). This allows the soft tissues to heal in a protected environment while preventing the severe stiffness that would result from prolonged immobilization. It does not allow for immediate full weight-bearing (Option A). While it helps to prevent stiffness, it does not completely prevent HO (Option C). It is often usedin conjunction withinternal fixation, not instead of it (Option D). It does not directly facilitate nerve regeneration (Option E).

Question 2939

Topic: 9. Shoulder and Elbow

What is the primary function of the anterior bundle of the medial ulnar collateral ligament (MUCL) in the elbow?

. Primary restraint to varus stress.
. Primary restraint to valgus stress.
. Stabilizes the radial head.
. Prevents posterior translation of the ulna.
. Guides the trochlea into the olecranon fossa during extension.

Correct Answer & Explanation

. Primary restraint to valgus stress.

Explanation

The anterior bundle of the medial ulnar collateral ligament (MUCL) is the primary static stabilizer against valgus stress at the elbow, particularly from 20 to 120 degrees of flexion. Its integrity is crucial for resisting forces that tend to open the medial side of the joint. It is not a primary restraint to varus stress (Option A), nor does it stabilize the radial head (Option C), prevent posterior translation of the ulna (Option D), or guide the trochlea (Option E).

Question 2940

Topic: 9. Shoulder and Elbow

A 68-year-old male with multiple comorbidities sustains an open elbow dislocation with significant soft tissue loss. What is the MOST appropriate initial management goal after debridement and reduction?

. Achieve definitive internal fixation of all bony structures.
. Immediate free flap coverage of the soft tissue defect.
. Prioritize wound coverage and infection control, possibly with external fixation for stability.
. Immediate elbow replacement arthroplasty.
. Prolonged immobilization in a cast.

Correct Answer & Explanation

. Prioritize wound coverage and infection control, possibly with external fixation for stability.

Explanation

For an open elbow dislocation with significant soft tissue loss, especially in a patient with comorbidities, the priority after debridement and reduction is wound coverage and infection control. This often involves delayed primary closure, local/regional flaps, or sometimes free flaps, and ensuring skeletal stability which may be achieved with external fixation, particularly if internal fixation is not feasible or desirable due to soft tissue compromise. Immediate definitive internal fixation (Option A) may not be possible or advisable due to the open wound and infection risk. Immediate free flap coverage (Option B) may not be theinitialgoal, but rather after initial debridement and assessment. Arthroplasty (Option D) is not an acute management option. Prolonged immobilization (Option E) increases infection risk and leads to stiffness.

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