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Elbow & Forearm MCQs

Practice Set 57 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 1121

Topic: Elbow & Forearm

A 10-year-old boy with multiple osteochondromas presents with a progressive forearm deformity. Which of the following is the classic pattern of forearm deformity expected in this patient due to the anarchic development of bone constituents?

. Radial shortening, ulnar bowing, and radial deviation of the hand
. Ulnar shortening, radial bowing, ulnar deviation of the hand, and potential radial head dislocation
. Equal shortening of radius and ulna with volar subluxation of the carpus
. Proximal radioulnar synostosis with fixed pronation contracture
. Madelung deformity with dorsal subluxation of the distal ulna

Correct Answer & Explanation

. Ulnar shortening, radial bowing, ulnar deviation of the hand, and potential radial head dislocation

Explanation

Correct Answer: Ulnar shortening, radial bowing, ulnar deviation of the hand, and potential radial head dislocationMultiple Hereditary Exostoses (MHE), also known as diaphyseal aclasis, is characterized by the anarchic development of cartilage-capped bony outgrowths. In the forearm, the distal ulna is disproportionately affected because it contributes a large percentage of the bone's overall longitudinal growth and has a small cross-sectional area. This leads to relative ulnar shortening. The radius continues to grow, resulting in radial bowing to accommodate the length discrepancy. The tethering effect leads to ulnar deviation of the carpus and can eventually cause dislocation of the radial head (usually posterolaterally).

Question 1122

Topic: Elbow & Forearm

A 10-year-old boy with multiple hereditary exostoses (MHE) presents with a progressive forearm deformity. Which of the following is the most characteristic pattern of forearm deformity seen in this condition?

. Radial shortening, ulnar bowing, and radial deviation of the carpus
. Ulnar shortening, radial bowing, ulnar deviation of the carpus, and radial head dislocation
. Equal shortening of the radius and ulna with volar subluxation of the carpus
. Proximal radioulnar synostosis with fixed pronation

Correct Answer & Explanation

. Ulnar shortening, radial bowing, ulnar deviation of the carpus, and radial head dislocation

Explanation

Correct Answer: Ulnar shortening, radial bowing, ulnar deviation of the carpus, and radial head dislocationThe classic forearm deformity in Multiple Hereditary Exostoses (MHE) is driven by the disproportionate shortening of the ulna. Because the ulna contributes less to the distal growth plate than the radius, osteochondromas at the distal ulna severely tether its growth. This leads to ulnar shortening, secondary bowing of the radius (which continues to grow but is tethered to the short ulna), ulnar deviation of the carpus (due to lack of ulnar support), and eventual dislocation of the radial head.

Question 1123

Topic: Elbow & Forearm

A 5-year-old girl sustains a minimally displaced lateral condyle fracture of the humerus that is treated nonoperatively. She is lost to follow-up and presents 15 years later with progressive numbness and tingling in her ring and small fingers. What is the most likely underlying cause of her current symptoms?

. Cubitus varus deformity
. Cubitus valgus deformity
. Recurrent elbow dislocations
. Heterotopic ossification
. Radial head overgrowth

Correct Answer & Explanation

. Cubitus valgus deformity

Explanation

Correct Answer: Cubitus valgus deformityNonunion is a classic complication of lateral condyle fractures, particularly if displacement is missed or inadequately treated. A nonunion of the lateral condyle leads to a progressive cubitus valgus deformity as the medial physis continues to grow while the lateral side does not. Over time, this valgus alignment stretches the ulnar nerve behind the medial epicondyle, leading to a tardy ulnar nerve palsy. This presents with numbness, tingling, and potential intrinsic muscle weakness in the ulnar nerve distribution.

Question 1124

Topic: Elbow & Forearm

A 6-year-old boy is evaluated for painless, limited forearm rotation. Radiographs demonstrate an isolated posterior dislocation of the radial head. Which of the following radiographic features most strongly supports a congenital rather than a traumatic etiology?

. A concave articular surface of the radial head
. A domed or convex radial head with a hypoplastic capitellum
. Presence of a healed Monteggia fracture
. Associated proximal radioulnar synostosis
. Hypertrophy of the olecranon process

Correct Answer & Explanation

. A domed or convex radial head with a hypoplastic capitellum

Explanation

Congenital dislocation of the radial head is typically posterior and characterized by adaptive changes from a lack of normal articulation. These include a domed or convex radial head, a hypoplastic or flattened capitellum, and bowing of the ulna.

Question 1125

Topic: Elbow & Forearm

A 10-year-old boy with multiple hereditary exostoses is being evaluated in the orthopedic clinic. Which of the following forearm deformities is most characteristic of this condition due to anarchic growth at the physes?

. Relative shortening of the radius with ulnar bowing
. Relative shortening of the ulna with radial bowing and ulnar deviation of the hand
. Volar subluxation of the distal radioulnar joint
. Proximal radioulnar synostosis
. Madelung-like deformity with dorsal subluxation of the ulna

Correct Answer & Explanation

. Relative shortening of the ulna with radial bowing and ulnar deviation of the hand

Explanation

Correct Answer: Relative shortening of the ulna with radial bowing and ulnar deviation of the handIn multiple hereditary exostoses, the distal ulna is disproportionately affected compared to the radius because the ulna relies more heavily on its distal physis for longitudinal growth, and its smaller cross-sectional area makes it more susceptible to growth arrest from exostoses. This leads to relative ulnar shortening. The continued growth of the radius against a tethered ulna causes radial bowing, ulnar deviation of the carpus, and often radial head subluxation or dislocation.

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