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 3541
Topic: Elbow & Forearm
Which of the following conditions is most likely to result in a 'gunstock deformity' (cubitus varus)?
Correct Answer & Explanation
. Untreated supracondylar humerus fracture in a child
Explanation
Cubitus varus, or 'gunstock deformity,' is most commonly caused by malunion of a supracondylar humerus fracture in a child. This typically occurs when the distal fragment rotates internally, leading to a varus angulation of the elbow in extension. The other conditions do not typically lead to this specific deformity.
Question 3542
Topic: 9. Shoulder and Elbow
A patient presents with a chronically painful, stiff elbow with a fixed flexion deformity of 30 degrees and an arc of motion of 70 degrees. Radiographs show diffuse degenerative changes. What is the main indication for interposition arthroplasty of the elbow?
Correct Answer & Explanation
. Young, active patients with end-stage arthritis where TEA is contraindicated
Explanation
Interposition arthroplasty (e.g., using fascia lata, dermis, or allograft) is generally reserved for younger, active patients with end-stage elbow arthritis where a total elbow arthroplasty (TEA) is contraindicated or carries too high a risk of failure due to the patient's activity level. It aims to provide a pain-relieving, albeit often limited motion, functional joint. TEA is preferred for older, low-demand patients. It's not a primary treatment for acute trauma or stiffness without arthritis, nor is it the primary revision strategy for failed TEA in most cases.
Question 3543
Topic: Elbow & Forearm
Which imaging modality is most sensitive for detecting early osteochondral lesions of the capitellum in an athlete?
Correct Answer & Explanation
. MRI with contrast
Explanation
MRI with contrast is the most sensitive imaging modality for detecting early osteochondral lesions of the capitellum, as it can visualize cartilage integrity, subchondral bone changes, and marrow edema, which are not well seen on plain radiographs or CT. Ultrasound is useful for soft tissues but limited for articular cartilage and bone. A bone scan can show increased metabolic activity but is not specific for an OCD lesion.
Question 3544
Topic: 9. Shoulder and Elbow
What is the primary function of the medial collateral ligament (MCL) complex of the elbow?
Correct Answer & Explanation
. Resist valgus stress
Explanation
The medial collateral ligament (MCL) complex, specifically the anterior bundle of the ulnar collateral ligament (UCL), is the primary static stabilizer that resists valgus stress at the elbow. The lateral collateral ligament (LCL) complex resists varus stress and posterolateral rotatory instability.
Question 3545
Topic: 9. Shoulder and Elbow
A 22-year-old weightlifter presents with chronic anterior elbow pain, particularly with heavy biceps curls. Examination reveals a painful 'pop' with resisted elbow flexion. MRI shows a partial tear of the distal biceps tendon. What is the most appropriate initial management?
Correct Answer & Explanation
. Rest, activity modification, NSAIDs, and physical therapy
Explanation
For a partial tear of the distal biceps tendon, especially in the chronic setting and without complete avulsion, initial management is typically conservative. This includes rest, activity modification (avoiding aggravating activities like heavy lifting), NSAIDs for pain, and a structured physical therapy program focusing on eccentric strengthening. Surgical repair is generally reserved for complete ruptures or failed conservative management of symptomatic partial tears. Injections are generally not recommended for partial tendon tears due to the risk of further degeneration or rupture. Cast immobilization is overly restrictive and can lead to stiffness.
Question 3546
Topic: Elbow & Forearm
What is the key to preventing recurrent posterolateral rotatory instability (PLRI) after operative repair?
Correct Answer & Explanation
. Repair or reconstruction of the lateral ulnar collateral ligament (LUCL)
Explanation
Posterolateral rotatory instability (PLRI) is caused by insufficiency of the lateral ulnar collateral ligament (LUCL). Therefore, the key to preventing recurrent instability after operative treatment is the anatomical repair or reconstruction of the LUCL. Other elements like good rehabilitation are important, but addressing the underlying ligamentous pathology is paramount. Aggressive early range of motion without adequate stability can lead to recurrence. Strict immobilization can lead to stiffness. Medial collateral ligament reconstruction is for valgus instability, and radial head excision can actually worsen stability.
Question 3547
Topic: Elbow & Forearm
A patient with chronic, recalcitrant lateral epicondylitis has failed 6 months of conservative management, including physical therapy, bracing, and a single corticosteroid injection. What is the next most appropriate step?
Correct Answer & Explanation
. Open surgical debridement of the ECRB origin
Explanation
After 6-12 months of failed comprehensive conservative management for chronic lateral epicondylitis, surgical intervention, typically open or arthroscopic debridement of the degenerative ECRB origin, is considered the next most appropriate step. Repeating corticosteroid injections is not recommended due to potential long-term negative effects. PRP injections have shown mixed results and are still considered experimental or second-line. MRI of the cervical spine is relevant if radiculopathy is suspected, but in a classic presentation with localized tenderness, surgical treatment of the elbow is more indicated. Further observation is unlikely to lead to resolution after extensive failed conservative care.
Question 3548
Topic: 9. Shoulder and Elbow
What is the primary role of the posterior bundle of the ulnar collateral ligament (UCL)?
Correct Answer & Explanation
. Secondary stabilizer against valgus stress in flexion, limiting full flexion
Explanation
The posterior bundle of the ulnar collateral ligament (UCL) is a fan-shaped structure that becomes taut in full elbow flexion. Its primary role is to act as a secondary stabilizer against valgus stress in flexion and to limit full elbow flexion. The anterior bundle is the primary valgus stabilizer, particularly between 30 and 120 degrees of flexion. The posterior bundle is distinct from the primary valgus stabilizers.
Question 3549
Topic: Elbow & Forearm
A 45-year-old male presents with chronic posterolateral rotatory instability (PLRI) of the elbow after a remote fall. He failed conservative management. Clinically, he has a positive lateral pivot shift test. Which of the following structures is primarily responsible for resisting posterolateral rotatory instability?
Correct Answer & Explanation
. Lateral ulnar collateral ligament (LUCL)
Explanation
The Lateral Ulnar Collateral Ligament (LUCL) is the primary static stabilizer preventing posterolateral rotatory instability of the elbow. Injury to the LUCL allows the ulna to rotate externally and subluxate posterolaterally on the capitellum, especially in supination and valgus stress. The anterior bundle of the medial collateral ligament is the primary valgus stabilizer. The annular ligament stabilizes the radial head but is not the primary restraint to PLRI. The posterior bundle of the MCL contributes to valgus stability but is less critical than the anterior bundle. The radial collateral ligament is part of the lateral collateral ligament complex but the LUCL is the specific component preventing PLRI.
Question 3550
Topic: Elbow & Forearm
A 32-year-old professional baseball pitcher presents with chronic medial elbow pain and valgus instability. MRI shows a complete tear of the ulnar collateral ligament (UCL). He desires to return to pitching. What is the most common graft used for UCL reconstruction (Tommy John surgery)?
Correct Answer & Explanation
. Semitendinosus autograft
Explanation
The semitendinosus autograft is the most commonly used graft for ulnar collateral ligament (UCL) reconstruction (Tommy John surgery) due to its sufficient length, strength, and low donor site morbidity. Palmaris longus is also frequently used if present and of adequate size. Patellar tendon and Achilles tendon grafts are typically reserved for larger joints like the knee or ankle. Peroneus longus is less commonly used. Flexor carpi radialis is another potential option but semitendinosus is generally preferred and more common.
Question 3551
Topic: 9. Shoulder and Elbow
What is the primary function of the anconeus muscle in elbow kinematics?
Correct Answer & Explanation
. Assists in elbow extension and stabilizes the ulna during pronation/supination
Explanation
The anconeus muscle is a small muscle located on the posterolateral aspect of the elbow. Its primary function is to assist the triceps in elbow extension and to stabilize the ulna, particularly during pronation and supination movements, preventing medial displacement of the ulna. It is not a primary flexor, supinator, or pronator.
Question 3552
Topic: 9. Shoulder and Elbow
What is the normal carrying angle of the elbow in adults, and how does it typically differ between sexes?
Correct Answer & Explanation
. 5-15 degrees of valgus, generally greater in females
Explanation
The normal carrying angle of the elbow is typically 5-15 degrees of valgus. This angle is generally slightly greater in females (around 10-15 degrees) than in males (around 5-10 degrees). The carrying angle allows the forearm to clear the hips during walking. Varus deformity is abnormal. Options indicating varus or no consistent angle are incorrect.
Question 3553
Topic: Elbow & Forearm
Which of the following describes the most common type of radial head fracture according to the Mason-Hotchkiss classification?
Correct Answer & Explanation
. Type I: Nondisplaced or minimally displaced fracture
Explanation
Type I radial head fractures (nondisplaced or minimally displaced) are the most common type, accounting for approximately 50% of all radial head fractures. They are typically managed conservatively. Type II involves displaced but reconstructible fragments, Type III is comminuted and often non-reconstructible, and Type IV (Hotchkiss modification) adds associated elbow dislocation.
Question 3554
Topic: 9. Shoulder and Elbow
A 50-year-old male presents with sudden onset of severe anterior elbow pain and a palpable 'Popeye' deformity in his arm after attempting to lift a heavy object. Examination reveals weakness in forearm supination and elbow flexion. What is the most appropriate management?
Correct Answer & Explanation
. Surgical repair of the distal biceps tendon
Explanation
The clinical presentation (sudden severe anterior elbow pain, 'Popeye' deformity, weakness in supination and elbow flexion) is classic for a distal biceps tendon rupture. For active individuals, especially those requiring strength in supination and flexion, surgical repair of the distal biceps tendon is the most appropriate management to restore strength and prevent chronic weakness. Non-operative management leads to significant loss of supination strength (up to 50%) and flexion strength. Injections are contraindicated in ruptures. Diagnostic arthroscopy is not the primary management.
Question 3555
Topic: 9. Shoulder and Elbow
What is the typical carrying angle range for the elbow?
Correct Answer & Explanation
. 5-15 degrees of valgus
Explanation
The carrying angle is the angle formed by the long axis of the humerus and the long axis of the ulna with the elbow in extension and the forearm in supination. A normal carrying angle is typically 5-15 degrees of valgus. An angle outside this range, especially a varus angle, can indicate a pathological condition.
Question 3556
Topic: 9. Shoulder and Elbow
Which of the following ligaments is considered the primary static stabilizer against valgus stress at the elbow?
Correct Answer & Explanation
. Anterior bundle of the medial collateral ligament (AMCL)
Explanation
The anterior bundle of the medial collateral ligament (AMCL) is the primary static stabilizer against valgus stress at the elbow. It is taut throughout the entire range of motion, providing significant resistance to medial opening of the joint. The LUCL is crucial for posterolateral rotatory stability. The radial collateral and annular ligaments contribute to lateral stability but not valgus. The posterior bundle of the MCL contributes to valgus stability at extremes of flexion but is secondary to the AMCL.
Question 3557
Topic: Elbow & Forearm
A 7-year-old child presents with a 'pulled elbow' (Nursemaid's elbow). What is the underlying pathology?
Correct Answer & Explanation
. Subluxation of the radial head from under the annular ligament
Explanation
Nursemaid's elbow, or radial head subluxation, occurs when the radial head slips out from under the annular ligament, usually due to a sudden pull on the child's extended and pronated arm. It is a subluxation, not a complete dislocation of the radiocapitellar joint. The annular ligament becomes trapped between the radial head and capitellum. It is not a fracture or ligament tear.
Question 3558
Topic: Elbow & Forearm
In a patient presenting with refractory lateral epicondylitis (tennis elbow), what is the primary pathology targeted by surgical intervention?
Correct Answer & Explanation
. Degeneration and angiofibroblastic hyperplasia of the extensor carpi radialis brevis (ECRB) origin
Explanation
While historically called 'epicondylitis' suggesting inflammation, the primary pathology in chronic lateral epicondylitis is actually degeneration and angiofibroblastic hyperplasia (tendinosis) of the origin of the extensor carpi radialis brevis (ECRB) tendon, with minimal inflammatory cells. Surgical interventions typically involve debridement of this degenerated tissue. Other options represent different pathologies or less common features.
Question 3559
Topic: 9. Shoulder and Elbow
What is the primary goal of surgical management for elbow stiffness and contracture?
Correct Answer & Explanation
. To achieve a functional arc of motion (approximately 30-130 degrees)
Explanation
The primary goal of surgical management for elbow stiffness is to achieve a functional arc of motion, typically considered to be approximately 30-130 degrees of flexion/extension. This range allows most activities of daily living. While achieving full range is ideal, it is often not realistic or necessary. Resecting HO is often part of the procedure, but the goal is functional motion. Prolonged immobilization is detrimental, early motion is key. TEA is reserved for end-stage arthritis or complex unreconstructible trauma.
Question 3560
Topic: 9. Shoulder and Elbow
A 40-year-old male presents with persistent elbow instability following a complex elbow dislocation that was managed non-operatively. Radiographs reveal chronic instability and articular damage. Which of the following conditions would make him a poor candidate for a simple ligamentous repair and would push toward a more complex reconstruction or arthroplasty?
Correct Answer & Explanation
. Significant articular cartilage loss and osteoarthritic changes
Explanation
Significant articular cartilage loss and established osteoarthritic changes are poor prognostic indicators for simple ligamentous repair and often preclude it as a standalone solution for instability. The joint surface itself is compromised, leading to pain and dysfunction even if stability is restored. In such cases, interposition arthroplasty, total elbow arthroplasty, or possibly an ulnohumeral arthroplasty might be considered depending on the extent of damage and patient factors. Mild varus or isolated LUCL insufficiency without significant arthritis would still be amenable to reconstructive procedures. Heterotopic ossification, while often present, doesn't directly preclude ligament repair but can complicate it.
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