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Elbow & Forearm MCQs

Practice Set 52 of 57

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

Question 1021

Topic: Elbow & Forearm

Which clinical test is most specific for diagnosing posterolateral rotatory instability (PLRI) of the elbow?

. Valgus stress test
. Varus stress test
. Moving valgus stress test
. Lateral pivot shift test of the elbow
. Cozen's test

Correct Answer & Explanation

. Lateral pivot shift test of the elbow

Explanation

The lateral pivot shift test of the elbow (or chair push-up test, posterior drawer test with valgus stress) is the most specific clinical test for diagnosing posterolateral rotatory instability (PLRI). This test reproduces the subluxation and reduction of the radial head and ulna relative to the humerus, which is pathognomonic for PLRI due to insufficiency of the lateral ulnar collateral ligament (LUCL). The valgus and varus stress tests assess the medial and lateral collateral ligaments respectively, while the moving valgus stress test assesses UCL integrity. Cozen's test is for lateral epicondylitis.

Question 1022

Topic: Elbow & Forearm

What is the primary stabilizer of the proximal radioulnar joint?

. Quadrate ligament
. Interosseous membrane
. Oblique cord
. Annular ligament
. Radial collateral ligament

Correct Answer & Explanation

. Annular ligament

Explanation

The annular ligament is the primary stabilizer of the proximal radioulnar joint. It encircles the radial head, holding it in firm apposition with the radial notch of the ulna, thereby allowing pronation and supination while preventing proximal migration or subluxation of the radial head. The interosseous membrane and oblique cord are distal to this joint and provide stability to the forearm generally. The quadrate ligament also contributes to PRUJ stability but is secondary to the annular ligament. The radial collateral ligament stabilizes the humeroradial joint.

Question 1023

Topic: Elbow & Forearm

Which of the following conditions is most likely to result in a 'gunstock deformity' (cubitus varus)?

. Untreated supracondylar humerus fracture in a child
. Chronic lateral epicondylitis
. Radial head fracture malunion
. Ulnar collateral ligament insufficiency
. Olecranon fracture malunion

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 1024

Topic: Elbow & Forearm

Which imaging modality is most sensitive for detecting early osteochondral lesions of the capitellum in an athlete?

. Plain radiographs
. CT scan
. MRI with contrast
. Ultrasound
. Bone scan

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 1025

Topic: Elbow & Forearm

What is the key to preventing recurrent posterolateral rotatory instability (PLRI) after operative repair?

. Aggressive early range of motion
. Strict immobilization for 6 weeks
. Repair or reconstruction of the lateral ulnar collateral ligament (LUCL)
. Medial collateral ligament reconstruction
. Radial head excision

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 1026

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?

. Repeat corticosteroid injection
. Platelet-rich plasma (PRP) injection
. Open surgical debridement of the ECRB origin
. MRI of the cervical spine
. Further observation with NSAIDs

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 1027

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?

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

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 1028

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)?

. Patellar tendon autograft
. Achilles tendon allograft
. Semitendinosus autograft
. Peroneus longus autograft
. Flexor carpi radialis autograft

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 1029

Topic: Elbow & Forearm
Which of the following describes the most common type of radial head fracture according to the Mason-Hotchkiss classification?
. Type I: Nondisplaced or minimally displaced fracture
. Type II: Single displaced fracture involving a significant portion of the articular surface
. Type III: Comminuted fracture involving the entire radial head
. Type IV: Radial head fracture with associated elbow dislocation
. Type IIIA: Resectable fragments

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 1030

Topic: Elbow & Forearm

A 7-year-old child presents with a 'pulled elbow' (Nursemaid's elbow). What is the underlying pathology?

. Radial head fracture
. Dislocation of the radiocapitellar joint
. Subluxation of the radial head from under the annular ligament
. Tear of the ulnar collateral ligament
. Supracondylar humerus fracture

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 1031

Topic: Elbow & Forearm

In a patient presenting with refractory lateral epicondylitis (tennis elbow), what is the primary pathology targeted by surgical intervention?

. Inflammation of the supinator muscle origin
. Degeneration and angiofibroblastic hyperplasia of the extensor carpi radialis brevis (ECRB) origin
. Tear of the lateral ulnar collateral ligament (LUCL)
. Compression of the posterior interosseous nerve (PIN)
. Calcification of the common extensor tendon

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 1032

Topic: Elbow & Forearm

Which muscle is most commonly implicated in medial epicondylitis (golfer's elbow)?

. Extensor carpi radialis brevis
. Supinator
. Pronator teres and flexor carpi radialis
. Biceps brachii
. Triceps brachii

Correct Answer & Explanation

. Pronator teres and flexor carpi radialis

Explanation

Medial epicondylitis, or golfer's elbow, is an overuse injury affecting the common flexor-pronator origin at the medial epicondyle. The pronator teres and flexor carpi radialis are the most commonly involved muscles. The extensor carpi radialis brevis is involved in lateral epicondylitis. Supinator, biceps, and triceps are not primarily implicated in medial epicondylitis.

Question 1033

Topic: Elbow & Forearm
A 25-year-old male sustains a comminuted radial head fracture (Mason Type III) with an associated MCL injury and elbow dislocation (terrible triad). What is the preferred treatment for the radial head component in this active patient?
. Excision of the radial head
. Open reduction and internal fixation (ORIF) of the radial head
. Radial head arthroplasty
. Long-term immobilization
. Percutaneous pinning of the radial head

Correct Answer & Explanation

. Radial head arthroplasty

Explanation

In a terrible triad injury with a comminuted, unreconstructible radial head fracture (Mason Type III) in an active patient, radial head arthroplasty is generally the preferred treatment. Excision of the radial head in the setting of a terrible triad can lead to persistent valgus instability and proximal migration of the radius. ORIF is ideal for reconstructible fractures (Mason Type II), but not for Type III comminution. Long-term immobilization is detrimental for elbow function. Percutaneous pinning is typically for very simple, minimally displaced fractures, not comminuted ones.

Question 1034

Topic: Elbow & Forearm

What is the characteristic radiographic finding in osteochondritis dissecans (OCD) of the capitellum?

. Widening of the trochlear groove
. Sclerosis and fragmentation of the capitellar articular surface
. Prominent osteophytes at the olecranon fossa
. Radial head subluxation
. Medial epicondyle apophysitis

Correct Answer & Explanation

. Sclerosis and fragmentation of the capitellar articular surface

Explanation

Osteochondritis dissecans (OCD) of the capitellum is an idiopathic aseptic necrosis of the subchondral bone, primarily affecting young athletes (e.g., gymnasts, baseball pitchers). Radiographically, it is characterized by sclerosis, fragmentation, and potential loosening of a segment of the capitellar articular surface. Other options describe different pathologies or non-specific findings.

Question 1035

Topic: Elbow & Forearm

Which structure provides the most significant secondary stability to the elbow, particularly in valgus stress, when the primary stabilizer (AMCL) is compromised?

. Radial head and capitellum articulation
. Common extensor origin
. Triceps tendon insertion
. Joint capsule (anterior and posterior)
. Anconeus muscle

Correct Answer & Explanation

. Radial head and capitellum articulation

Explanation

The radial head and capitellum articulation provide significant secondary stability to the elbow, especially against valgus stress, once the primary stabilizer (anterior bundle of the medial collateral ligament) is compromised. This is why excision of the radial head in the setting of valgus instability (e.g., terrible triad) can exacerbate the instability. The other options contribute less directly or significantly to static valgus stability.

Question 1036

Topic: Elbow & Forearm

What is the primary concern when managing a displaced lateral condyle fracture of the humerus in a 6-year-old child?

. Radial nerve entrapment
. Ulnar nerve palsy
. Nonunion and cubitus valgus deformity
. Brachial artery injury
. Posterolateral rotatory instability

Correct Answer & Explanation

. Nonunion and cubitus valgus deformity

Explanation

Displaced lateral condyle fractures in children are prone to nonunion, especially if not adequately fixed. A nonunion of the lateral condyle can lead to a progressive cubitus valgus deformity, which can then cause a delayed ulnar nerve palsy (tardy ulnar palsy). Therefore, preventing nonunion and subsequent deformity is a primary concern. Nerve and vascular injuries are less common than with supracondylar fractures. PLRI is associated with LUCL injury.

Question 1037

Topic: Elbow & Forearm

When performing Maudsley's test, which specific finding indicates a positive result and points towards lateral epicondylitis?

. Pain over the medial epicondyle with resisted wrist flexion.
. Pain over the lateral epicondyle with resisted supination.
. Pain over the lateral epicondyle with resisted extension of the third digit (middle finger).
. Pain over the dorsal aspect of the wrist with resisted wrist flexion.
. Pain in the biceps groove with resisted forearm supination.

Correct Answer & Explanation

. Pain over the lateral epicondyle with resisted extension of the third digit (middle finger).

Explanation

Maudsley's test, also known as the 'middle finger extension test,' specifically assesses the extensor digitorum communis (EDC) which has a common origin with the ECRB. A positive test involves pain over the lateral epicondyle with resisted extension of the third digit (middle finger). This test places direct stress on the common extensor origin. Options A, B, D, and E describe tests for medial epicondylitis, radial tunnel, wrist pain, or biceps pathology respectively.

Question 1038

Topic: Elbow & Forearm

What is the typical sensory deficit, if any, associated with a true lateral epicondylitis?

. Numbness in the little finger and ulnar half of the ring finger.
. Hypesthesia in the dorsal web space of the thumb and index finger.
. Decreased sensation along the lateral forearm.
. No specific sensory deficit.
. Paresthesias in the thumb, index, and middle fingers.

Correct Answer & Explanation

. No specific sensory deficit.

Explanation

Lateral epicondylitis is a tendinopathy and does not directly cause specific sensory nerve deficits. If sensory changes are present, they point towards a differential diagnosis such as cervical radiculopathy (C6-C7), radial tunnel syndrome (though primarily motor), or less commonly, superficial radial nerve entrapment (which would cause sensory changes on the dorsal thumb/index finger). Therefore, a pure lateral epicondylitis, without nerve involvement, should present with no specific sensory deficits.

Question 1039

Topic: Elbow & Forearm

When evaluating a patient with suspected lateral epicondylitis, which observation, if present, would most strongly suggest an alternative diagnosis such as radiohumeral osteoarthritis?

. Pain with resisted wrist extension.
. Point tenderness over the lateral epicondyle.
. Crepitus and pain with forearm pronation/supination.
. Pain relief with rest.
. Weak grip strength.

Correct Answer & Explanation

. Crepitus and pain with forearm pronation/supination.

Explanation

While pain with resisted wrist extension and point tenderness are hallmarks of lateral epicondylitis, crepitus and pain specifically with forearm pronation and supination are highly indicative of intra-articular pathology, such as radiohumeral osteoarthritis, or possibly a plica. These mechanical symptoms are less typical for isolated tendinopathy. Pain relief with rest and weak grip strength can be present in both conditions to varying degrees.

Question 1040

Topic: Elbow & Forearm

Which of the following laboratory tests is most helpful in the routine diagnosis and workup of lateral epicondylitis?

. Erythrocyte Sedimentation Rate (ESR)
. C-Reactive Protein (CRP)
. Rheumatoid Factor (RF)
. Complete Blood Count (CBC)
. None of the above

Correct Answer & Explanation

. None of the above

Explanation

Lateral epicondylitis is a clinical diagnosis based on history and physical examination. There are no specific laboratory tests that diagnose or are routinely helpful in the workup of uncomplicated lateral epicondylitis. ESR, CRP, and RF might be considered if an inflammatory arthropathy is suspected as a differential, but not for typical lateral epicondylitis. CBC is a general health screen. Therefore, none of the listed tests are routinely indicated.

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