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9. Shoulder and Elbow MCQs

Practice Set 146 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 2901

Topic: Elbow & Forearm

What is the MOST critical biomechanical consequence of a lateral ulnar collateral ligament (LUCL) insufficiency in the elbow?

. Increased valgus instability.
. Increased varus instability.
. Posterolateral rotatory instability (PLRI).
. Increased anterior-posterior translation of the radial head.
. Loss of elbow flexion.

Correct Answer & Explanation

. Posterolateral rotatory instability (PLRI).

Explanation

Insufficiency or rupture of the lateral ulnar collateral ligament (LUCL) is the hallmark cause of posterolateral rotatory instability (PLRI) of the elbow. The LUCL originates from the lateral epicondyle and inserts on the supinator crest of the ulna, forming a sling that stabilizes the ulna and radius against posterolateral displacement from the humerus, especially during supination and valgus stress. It does not primarily cause valgus or varus instability directly (though secondary varus may result from severe PLRI). Anterior-posterior translation (Option D) or loss of flexion (Option E) are not direct consequences.

Question 2902

Topic: Elbow & Forearm

A 70-year-old patient with osteoporosis sustains a posterior elbow dislocation with a highly comminuted radial head fracture that is not amenable to open reduction and internal fixation. What is the MOST appropriate management strategy for the radial head in this 'terrible triad' setting?

. Excision of the radial head to prevent impingement.
. Delay surgical intervention until soft tissue swelling resolves.
. Radial head arthroplasty with an appropriate implant.
. Long-term immobilization in a cast.
. Perform a wrist arthrodesis to offload the elbow.

Correct Answer & Explanation

. Radial head arthroplasty with an appropriate implant.

Explanation

In the setting of a terrible triad injury, a highly comminuted radial head fracture not amenable to repair necessitates restoration of the radial column length and joint congruity. Radial head arthroplasty with an appropriate implant (Option C) is generally the preferred method to achieve this, as it helps stabilize the elbow, especially in the context of a deficient LUCL and coronoid fracture. Excision of the radial head (Option A) is contraindicated in terrible triad injuries, as it further destabilizes the elbow and can lead to proximal migration of the radius and secondary wrist pain. Delaying surgery (Option B) is inappropriate for an acute complex injury. Long-term immobilization (Option D) leads to severe stiffness and does not address the instability. Wrist arthrodesis (Option E) is irrelevant.

Question 2903

Topic: 9. Shoulder and Elbow

What is the MOST common long-term complication following a simple posterior elbow dislocation treated non-operatively?

. Recurrent dislocation.
. Heterotopic ossification.
. Ulnar nerve neuropathy.
. Elbow stiffness (loss of range of motion).
. Post-traumatic arthritis.

Correct Answer & Explanation

. Elbow stiffness (loss of range of motion).

Explanation

Elbow stiffness (loss of range of motion), particularly extension, is the most common long-term complication following a simple posterior elbow dislocation, especially with prolonged immobilization. Early controlled motion protocols aim to mitigate this. While heterotopic ossification (Option B) can occur and contribute to stiffness, it is not as universally common as general stiffness. Recurrent dislocation (Option A) is relatively rare after simple dislocations. Ulnar nerve neuropathy (Option C) is an acute complication. Post-traumatic arthritis (Option E) is a long-term risk but less common than stiffness after a simple dislocation.

Question 2904

Topic: Elbow & Forearm

In the setting of a persistent valgus instability after elbow dislocation, which structure is MOST likely to be deficient or ruptured?

. Lateral ulnar collateral ligament (LUCL).
. Annular ligament.
. Anterior bundle of the medial ulnar collateral ligament (MUCL).
. Posterior bundle of the medial ulnar collateral ligament (MUCL).
. Radial collateral ligament (RCL).

Correct Answer & Explanation

. Anterior bundle of the medial ulnar collateral ligament (MUCL).

Explanation

The anterior bundle of the medial ulnar collateral ligament (MUCL) is the primary static stabilizer against valgus stress in the elbow. Its rupture or insufficiency will lead to valgus instability. The LUCL (Option A) causes posterolateral rotatory instability. The annular ligament (Option B) stabilizes the radial head to the ulna. The posterior bundle of the MUCL (Option D) also contributes to valgus stability but the anterior bundle is the primary restraint. The RCL (Option E) provides varus stability.

Question 2905

Topic: 9. Shoulder and Elbow

Which of the following statements regarding heterotopic ossification (HO) following elbow dislocation is TRUE?

. HO is more common in simple dislocations treated with early motion.
. Prophylactic low-dose radiation therapy is indicated for all complex elbow dislocations.
. Non-steroidal anti-inflammatory drugs (NSAIDs) are ineffective in preventing HO.
. HO is strongly associated with prolonged immobilization and severe soft tissue injury.
. Surgical excision of HO should ideally be performed within 6 weeks of diagnosis.

Correct Answer & Explanation

. HO is strongly associated with prolonged immobilization and severe soft tissue injury.

Explanation

Heterotopic ossification (HO) is strongly associated with severe soft tissue injury, prolonged immobilization, and high-energy trauma, especially in complex elbow dislocations (Option D). Early motion protocols actually help prevent stiffness and HO in simple dislocations (refuting A). Prophylactic low-dose radiation or NSAIDs (like indomethacin) are indicated forhigh-riskpatients (e.g., severe open injuries, head injury, recurrent dislocations, burn patients), not all complex dislocations (refuting B). NSAIDs are effective in preventing HO (refuting C). Surgical excision of HO (Option E) is typically delayed until the HO is mature and the elbow is quiescent, usually 6 to 12 months after the injury, to minimize recurrence.

Question 2906

Topic: 9. Shoulder and Elbow

A patient sustained an elbow dislocation 8 weeks ago and was treated with prolonged immobilization. They now present with severe elbow stiffness, a flexion contracture of 45 degrees, and maximum flexion to 90 degrees. Radiographs show no significant HO. What is the MOST appropriate initial treatment for this chronic stiffness?

. Immediate surgical capsular release and manipulation under anesthesia.
. Aggressive passive stretching exercises at home.
. Intra-articular corticosteroid injections.
. Intensive supervised physical therapy with dynamic splinting or serial casting.
. Referral for elbow arthroplasty.

Correct Answer & Explanation

. Intensive supervised physical therapy with dynamic splinting or serial casting.

Explanation

For chronic elbow stiffness without significant heterotopic ossification, intensive supervised physical therapy, often supplemented with dynamic splinting or serial casting, is the most appropriate initial treatment. This aims to gradually restore range of motion. Immediate surgical capsular release (Option A) is typically reserved for cases that fail conservative management or have severe structural blocks. Aggressive passive stretching (Option B) can be counterproductive and cause further microtrauma and inflammation. Corticosteroid injections (Option C) are not indicated for mechanical stiffness. Elbow arthroplasty (Option E) is a salvage procedure for end-stage arthritis or irreparable joint destruction, not primary stiffness management.

Question 2907

Topic: 9. Shoulder and Elbow

Which of the following is considered a dynamic stabilizer of the elbow joint?

. Anterior bundle of the MUCL.
. Lateral ulnar collateral ligament (LUCL).
. Coronoid process.
. Anconeus muscle.
. Olecranon.

Correct Answer & Explanation

. Anconeus muscle.

Explanation

The anconeus muscle (Option D) is considered a dynamic stabilizer of the elbow. It originates from the lateral epicondyle and inserts on the olecranon and posterior ulna, and it helps stabilize the elbow during pronation and supination, and also assists in extension. The MUCL (Option A), LUCL (Option B), coronoid process (Option C), and olecranon (Option E) are all static stabilizers (ligamentous or bony).

Question 2908

Topic: Elbow & Forearm

A 25-year-old rugby player presents with a recent elbow dislocation. Post-reduction, the elbow is stable in full flexion but dislocates with pronation and extension, especially when a valgus stress is applied. Which specific ligament injury is MOST likely responsible for this instability pattern?

. Medial ulnar collateral ligament (MUCL) - anterior bundle.
. Lateral ulnar collateral ligament (LUCL).
. Radial collateral ligament (RCL).
. Annular ligament.
. Posterior bundle of the MUCL.

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL).

Explanation

The described instability pattern (dislocates with pronation, extension, and valgus stress) is classic for posterolateral rotatory instability (PLRI), which is caused by a rupture of the lateral ulnar collateral ligament (LUCL) complex. When the LUCL is disrupted, the radius and ulna subluxate posterolaterally on the humerus, particularly with the forearm in supination and the elbow in extension and valgus stress (often tested with a pivot shift maneuver). This pattern is not due to MUCL (Option A and E) which causes valgus instability, RCL (Option C) which causes varus instability, or annular ligament (Option D) which stabilizes the radial head to the ulna.

Question 2909

Topic: Elbow & Forearm

What is the typical sequence of ligamentous disruption in a posterolateral rotatory instability (PLRI) injury of the elbow, starting with the least severe?

. Medial collateral ligament, anterior capsule, lateral collateral ligament.
. Lateral collateral ligament, anterior capsule, medial collateral ligament.
. Annular ligament, radial collateral ligament, medial collateral ligament.
. Coronoid process fracture, radial head fracture, lateral collateral ligament.
. Posterior capsule, anterior capsule, lateral collateral ligament.

Correct Answer & Explanation

. Lateral collateral ligament, anterior capsule, medial collateral ligament.

Explanation

The 'Horii-Morrey circle of instability' describes the typical pattern of soft tissue disruption in progressive posterolateral rotatory instability (PLRI), which is the most common form of elbow dislocation. The sequence starts laterally and progresses medially: 1) disruption of the lateral collateral ligament (LUCL/LCL complex), 2) disruption of the anterior and posterior capsule, and then 3) disruption of the medial collateral ligament (MUCL). Therefore, Option B is the correct representation of this sequence.

Question 2910

Topic: 9. Shoulder and Elbow

What is the primary goal of surgical management for a 'terrible triad' injury of the elbow?

. Achieve full range of motion immediately.
. Relieve ulnar nerve compression.
. Restore stability, allow early motion, and achieve concentric reduction.
. Prevent heterotopic ossification.
. Excision of all small comminuted fragments.

Correct Answer & Explanation

. Restore stability, allow early motion, and achieve concentric reduction.

Explanation

The primary goal of surgical management for a terrible triad injury is to restore elbow stability (primarily by repairing the LUCL and fixing the coronoid), achieve concentric reduction, and allow for early range of motion to prevent stiffness. This complex injury requires a stable construct to enable early rehabilitation. While full ROM (Option A) is a long-term goal, it's not the immediate primary surgical goal. Relieving ulnar nerve compression (Option B) may be an additional step if present, but not the primary goal of triad repair. Preventing HO (Option D) is a secondary consideration. Excision of all fragments (Option E) is generally avoided if possible to preserve bone stock and joint mechanics, especially for the radial head.

Question 2911

Topic: 9. Shoulder and Elbow

In an anterior elbow dislocation, which structure is MOST commonly interposed within the joint, preventing closed reduction?

. Radial head.
. Olecranon.
. Medial epicondyle.
. Lateral epicondyle.
. Brachialis muscle.

Correct Answer & Explanation

. Olecranon.

Explanation

Anterior elbow dislocations are rare. When they occur and are irreducible by closed means, the most common interposing structure is the olecranon (Option B), which can become buttonholed through the brachialis muscle. The brachialis muscle (Option E) itself can also be entrapped, but the olecranon getting stuck through it is the mechanical block. Medial epicondyle (Option C) and lateral epicondyle (Option D) entrapment are more characteristic of posterior dislocations. Radial head (Option A) is part of the dislocation, not an interposing structure.

Question 2912

Topic: 9. Shoulder and Elbow

What is the typical position of immobilization for a simple, stable posterior elbow dislocation following successful closed reduction?

. Full extension and supination.
. Full flexion and pronation.
. Neutral rotation, 90 degrees of flexion.
. Slight flexion (20-30 degrees) and pronation.
. Full supination, 60 degrees of flexion.

Correct Answer & Explanation

. Neutral rotation, 90 degrees of flexion.

Explanation

For a simple, stable posterior elbow dislocation, the elbow is typically immobilized in approximately 90 degrees of flexion (to maximize stability by engaging the coronoid and olecranon with their fossae) and neutral or pronation (to minimize tension on the healing lateral ulnar collateral ligament). Option C represents this. Full extension (Option A) is unstable. Full flexion (Option B) can cause neurovascular compromise. Slight flexion (Option D) might be too extended for initial stability in some cases. Full supination (Option E) can tension the LUCL and promote posterolateral rotatory instability.

Question 2913

Topic: 9. Shoulder and Elbow

A 30-year-old construction worker falls, sustaining a posterior elbow dislocation. After reduction, an X-ray reveals a small avulsion fracture from the tip of the coronoid. The elbow is stable through a full range of motion. What is the MOST appropriate next step?

. Surgical fixation of the coronoid tip fracture.
. Immobilization in 30 degrees of extension.
. Immediate active range of motion with a hinged elbow brace.
. Long arm cast immobilization for 6 weeks.
. Repeat CT scan to assess fracture morphology.

Correct Answer & Explanation

. Immediate active range of motion with a hinged elbow brace.

Explanation

A small avulsion fracture from the tip of the coronoid (Regan-Morrey Type I) that does not compromise stability after reduction is often treated non-operatively. Since the elbow is stable through a full range of motion, immediate active range of motion with a hinged elbow brace (Option C) is the most appropriate next step. This prevents stiffness, which is a major complication of prolonged immobilization. Surgical fixation (Option A) is generally not indicated for small, stable coronoid tip fractures. Immobilization in extension (Option B) is unstable. Long arm cast for 6 weeks (Option D) would lead to severe stiffness. CT scan (Option E) might be useful if stability was questionable, but not in this stable scenario.

Question 2914

Topic: Elbow & Forearm

When performing a surgical repair of the lateral ulnar collateral ligament (LUCL) for posterolateral rotatory instability, where is the most critical anatomical attachment point to recreate for stability?

. Capitellum.
. Lateral epicondyle.
. Radial head neck.
. Supinator crest of the ulna.
. Medial epicondyle.

Correct Answer & Explanation

. Lateral epicondyle.

Explanation

The lateral ulnar collateral ligament (LUCL) originates from the lateral epicondyle (Option B) of the humerus and inserts onto the supinator crest of the ulna (Option D), forming a 'sling' that prevents posterolateral rotatory displacement of the ulna. Therefore, to recreate stability, both the origin and insertion are critical. However, specifically the lateral epicondyle is where the complex originates, and a direct repair or reconstruction must re-attach or anchor here. The question asks for 'attachment point to recreate for stability', and the epicondyle is the origin. The supinator crest is the insertion. The LUCL is distinct from the radial collateral ligament that attaches to the annular ligament. Hence, the lateral epicondyle is the most critical anatomical point to recreate the proximal attachment.

Question 2915

Topic: 9. Shoulder and Elbow

What is the primary function of the annular ligament in the elbow joint?

. Stabilizes the humeroulnar joint against varus stress.
. Primary restraint to valgus stress.
. Maintains the radial head in approximation with the radial notch of the ulna.
. Prevents posterior translation of the ulna.
. Connects the ulna to the humerus.

Correct Answer & Explanation

. Maintains the radial head in approximation with the radial notch of the ulna.

Explanation

The annular ligament encircles the radial head and holds it firmly against the radial notch of the ulna, allowing it to rotate while providing stability. It is a key component of the proximal radioulnar joint (Option C). It does not primarily stabilize against varus (Option A) or valgus (Option B) stress, nor does it directly prevent posterior translation of the ulna (Option D) or connect the ulna to the humerus (Option E).

Question 2916

Topic: 9. Shoulder and Elbow

A 22-year-old male sustains an elbow dislocation. After successful reduction, radiographs show a comminuted radial head fracture, but the elbow remains stable in extension. He has no neurovascular deficits. What is the BEST immediate plan for management of the radial head fracture?

. Excision of the radial head.
. Immobilization in a long arm cast for 4 weeks.
. Radial head arthroplasty.
. Open reduction and internal fixation (ORIF) of the radial head if possible, followed by early motion.
. Immediate elbow arthroplasty.

Correct Answer & Explanation

. Radial head arthroplasty.

Explanation

Given a comminuted radial head fracture (which typically implies an Essex-Lopresti type injury or complex radial head fracture) in the setting of a reduced elbow dislocation, the goal is to stabilize the elbow and restore radial column length. If the fracture is comminuted and not amenable to ORIF (Option D), and the elbow is stable in extension (suggesting the lateral collateral ligament may still be competent or healing), then radial head arthroplasty (Option C) is often the best option to restore stability and allow early motion. Excision of the radial head (Option A) is contraindicated as it destabilizes the forearm. Immobilization (Option B) will lead to severe stiffness and may not maintain reduction. Elbow arthroplasty (Option E) is excessive.

Question 2917

Topic: 9. Shoulder and Elbow

Which of the following scenarios would MOST strongly indicate the need for a computed tomography (CT) scan in a patient with an elbow dislocation?

. Simple posterior dislocation with intact neurovascular status.
. Post-reduction, the elbow appears stable on clinical examination.
. Suspicion of occult intra-articular fracture fragments or impaction after plain radiographs.
. Prior history of multiple elbow dislocations.
. Patient expresses concern about post-traumatic arthritis.

Correct Answer & Explanation

. Suspicion of occult intra-articular fracture fragments or impaction after plain radiographs.

Explanation

A CT scan is most strongly indicated when there is suspicion of occult intra-articular fracture fragments, incarcerated fragments, or complex fracture patterns (e.g., coronoid, radial head) that are not clearly visualized or fully characterized by plain radiographs (Option C). This is particularly true if stability cannot be adequately assessed or if surgical intervention is contemplated. Simple dislocations (Option A), clinically stable elbows (Option B), or previous dislocations (Option D) typically do not warrant a CT as a primary step. Concerns about arthritis (Option E) are usually addressed with follow-up imaging, not emergent CT.

Question 2918

Topic: 9. Shoulder and Elbow
What is the primary risk of attempting vigorous closed reduction on a chronic, unreduced elbow dislocation (e.g., >3 weeks)?
. Development of heterotopic ossification.
. Iatrogenic fracture of the humerus or ulna.
. Increased likelihood of recurrent dislocation.
. Delayed union of associated fractures.
. Deep vein thrombosis.

Correct Answer & Explanation

. Iatrogenic fracture of the humerus or ulna.

Explanation

Attempting vigorous closed reduction on a chronic, unreduced elbow dislocation carries a high risk of iatrogenic fracture of the humerus (especially the supracondylar region), ulna (coronoid or olecranon), or radial head, due to soft tissue contracture, fibrosis, and potential osteopenia or remodeling. Neurovascular injury is also a significant concern.

Question 2919

Topic: Elbow & Forearm

A patient is undergoing open reduction and internal fixation of a terrible triad injury. After coronoid and radial head fixation, the elbow remains unstable with a positive pivot shift test (posterolateral rotatory instability). What is the MOST crucial next step to restore stability?

. Apply an external fixator across the elbow.
. Perform a medial collateral ligament repair.
. Reinforce the anterior capsule.
. Perform a lateral ulnar collateral ligament (LUCL) repair or reconstruction.
. Consider radial head excision to decompress the joint.

Correct Answer & Explanation

. Perform a lateral ulnar collateral ligament (LUCL) repair or reconstruction.

Explanation

A positive pivot shift test after coronoid and radial head fixation indicates persistent posterolateral rotatory instability, which is primarily due to insufficiency of the lateral ulnar collateral ligament (LUCL) complex. Therefore, performing a lateral ulnar collateral ligament (LUCL) repair or reconstruction is the most crucial next step to restore stability in this scenario. While an external fixator (Option A) can be used as an adjunct, it is not the primary stabilizing procedure for the LUCL. Medial collateral ligament repair (Option B) addresses valgus instability, not PLRI. Reinforcing the anterior capsule (Option C) is less critical than addressing the LUCL. Radial head excision (Option D) would further destabilize the elbow.

Question 2920

Topic: 9. Shoulder and Elbow

Which of the following features is MOST indicative of a complex elbow dislocation, requiring surgical consideration?

. Posterior dislocation pattern.
. Associated ulnar nerve palsy.
. Grossly unstable after closed reduction.
. Patient age < 10 years.
. Presence of a full-thickness tear of the medial collateral ligament (MCL).

Correct Answer & Explanation

. Grossly unstable after closed reduction.

Explanation

A complex elbow dislocation is defined by the presence of an associated fracture that compromises stability, or an open injury. Gross instability after closed reduction (Option C) strongly suggests significant bony or ligamentous disruption (e.g., terrible triad), making it complex and often requiring surgery. While ulnar nerve palsy (Option B) is a complication, it doesn't define the complexity of the joint injury itself in terms of bony or ligamentous stability. Posterior dislocations (Option A) are common and can be simple or complex. Age < 10 years (Option D) suggests different considerations but doesn't define complexity. A full-thickness tear of the MCL (Option E) indicates valgus instability but doesn't encompass the breadth of complex injuries as well as 'grossly unstable after reduction' which typically implies multi-ligamentous or fracture involvement.

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