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Elbow & Forearm MCQs

Practice Set 56 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 1101

Topic: Elbow & Forearm

A 6-month-old infant is found to have an irreducible, complete dislocation of the radial head. The forearm is in pronation and flexion, and there is limited supination. Radiographs confirm radial head dislocation and an abnormal radial head configuration. The child has no other obvious deformities. What is the most likely underlying condition?

. Nursemaid's elbow
. Congenital radial head dislocation
. Monteggia fracture-dislocation
. Madelung's deformity
. Olecranon fracture

Correct Answer & Explanation

. Congenital radial head dislocation

Explanation

The description of an irreducible, complete radial head dislocation with an abnormal radial head configuration in a 6-month-old infant, without history of trauma (implying congenital), is characteristic of congenital radial head dislocation. Nursemaid's elbow is a subluxation of the radial head that is usually reducible and occurs after a pull injury. A Monteggia fracture-dislocation involves a fracture of the ulna with radial head dislocation, typically traumatic. Madelung's deformity involves dorsal subluxation of the distal ulna with premature physeal closure of the distal radius. Olecranon fracture is a traumatic elbow injury.

Question 1102

Topic: Elbow & Forearm

A 35-year-old male falls on an outstretched hand, sustaining a "terrible triad" injury of the elbow. What is the most widely accepted surgical sequence for reconstructing this injury pattern?

. LCL repair, coronoid fixation, radial head fixation/replacement
. Coronoid fixation, radial head fixation/replacement, LCL repair
. Radial head fixation/replacement, LCL repair, coronoid fixation
. MCL repair, LCL repair, radial head fixation
. Coronoid fixation, MCL repair, radial head replacement

Correct Answer & Explanation

. Coronoid fixation, radial head fixation/replacement, LCL repair

Explanation

The standard surgical sequence for a terrible triad injury proceeds from deep-to-superficial. It involves fixing the coronoid first, followed by addressing the radial head, and finally repairing the lateral collateral ligament (LCL) complex.

Question 1103

Topic: Elbow & Forearm

A 45-year-old male falls on his outstretched hand and sustains a 'terrible triad' injury of the elbow. What is the standard sequence of surgical reconstruction for this injury?

. Medial collateral ligament, coronoid, radial head, lateral collateral ligament
. Radial head, coronoid, lateral collateral ligament, medial collateral ligament
. Coronoid, radial head, lateral ulnar collateral ligament, medial collateral ligament
. Lateral ulnar collateral ligament, radial head, coronoid, medial collateral ligament

Correct Answer & Explanation

. Coronoid, radial head, lateral ulnar collateral ligament, medial collateral ligament

Explanation

The standard surgical algorithm for a terrible triad injury involves repairing structures from deep to superficial: coronoid first, followed by the radial head, then the lateral ulnar collateral ligament (LUCL). The medial collateral ligament (MCL) is only addressed if the elbow remains residually unstable in extension.

Question 1104

Topic: Elbow & Forearm

A 35-year-old bodybuilder feels a pop in his anterior elbow during a deadlift. He has a positive hook test. Which intact structure may limit the proximal retraction of the torn distal biceps tendon, potentially masking the cosmetic deformity?

. Brachialis muscle
. Bicipital aponeurosis (Lacertus fibrosus)
. Pronator teres
. Brachioradialis

Correct Answer & Explanation

. Bicipital aponeurosis (Lacertus fibrosus)

Explanation

The bicipital aponeurosis (lacertus fibrosus) expands from the distal biceps tendon to the antebrachial fascia. If it remains intact during a distal biceps rupture, it prevents severe proximal retraction of the muscle belly, sometimes masking the classic 'Popeye' deformity.

Question 1105

Topic: Elbow & Forearm

A patient presents with painful clicking and subjective instability when pushing out of a chair. Posterolateral rotatory instability (PLRI) of the elbow is suspected. The primary deficient structure originates from which anatomic location?

. Lateral epicondyle and inserts on the supinator crest
. Medial epicondyle and inserts on the sublime tubercle
. Lateral epicondyle and inserts on the radial neck
. Capitellum and inserts on the annular ligament

Correct Answer & Explanation

. Lateral epicondyle and inserts on the supinator crest

Explanation

PLRI is caused by incompetence of the lateral ulnar collateral ligament (LUCL). The LUCL originates on the lateral epicondyle and inserts on the supinator crest of the proximal ulna, acting as a crucial secondary stabilizer to varus stress and primary stabilizer to posterolateral rotation.

Question 1106

Topic: Elbow & Forearm

A 45-year-old man undergoes repair of a distal biceps tendon rupture using a single anterior incision approach. Postoperatively, he notes numbness along the lateral aspect of his forearm. Which nerve was most likely injured or retracted excessively during the procedure?

. Superficial radial nerve
. Posterior interosseous nerve
. Lateral antebrachial cutaneous nerve
. Medial antebrachial cutaneous nerve
. Anterior interosseous nerve

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve

Explanation

The lateral antebrachial cutaneous nerve (LABC) is the most commonly injured nerve during a single-incision anterior approach for distal biceps repair due to its superficial course. The posterior interosseous nerve (PIN) is classically more at risk during a two-incision approach.

Question 1107

Topic: Elbow & Forearm

According to standard surgical protocols for a 'terrible triad' injury of the elbow, which of the following represents the most widely accepted sequence of structural repair?

. LCL -> MCL -> Radial head -> Coronoid
. Coronoid -> Radial head -> LCL -> MCL (if needed)
. Radial head -> LCL -> Coronoid -> MCL
. MCL -> Coronoid -> Radial head -> LCL
. LCL -> Coronoid -> Radial head -> Extensor origin

Correct Answer & Explanation

. Coronoid -> Radial head -> LCL -> MCL (if needed)

Explanation

The standard sequence for repairing a terrible triad injury works from deep to superficial: fixing the coronoid first, followed by the radial head (repair or replacement), and then the lateral collateral ligament (LCL). The MCL is only addressed if persistent instability remains after these steps.

Question 1108

Topic: Elbow & Forearm

Posterolateral rotatory instability (PLRI) of the elbow is primarily caused by incompetence of the lateral ulnar collateral ligament (LUCL). What is the exact anatomic insertion of the LUCL on the ulna?

. Coronoid tubercle
. Sublime tubercle
. Olecranon tip
. Supinator crest
. Radial notch

Correct Answer & Explanation

. Supinator crest

Explanation

The LUCL originates from the lateral epicondyle and blends with the annular ligament before inserting on the supinator crest of the proximal ulna. Disruption of this ligament leads to PLRI.

Question 1109

Topic: Elbow & Forearm

A 45-year-old male sustains a severely comminuted, unsalvageable radial head fracture along with a complete tear of the interosseous membrane and distal radioulnar joint disruption. What is the most appropriate management of the proximal radius?

. Radial head excision alone
. Radial head arthroplasty
. Closed reduction and casting
. Open reduction internal fixation of the radial head regardless of comminution
. Resection of the proximal radius to the bicipital tuberosity

Correct Answer & Explanation

. Radial head arthroplasty

Explanation

This patient has an Essex-Lopresti injury. Radial head excision alone is absolutely contraindicated as it will lead to proximal migration of the radius and severe ulnar-sided wrist pain. Radial head arthroplasty is required to maintain longitudinal stability.

Question 1110

Topic: Elbow & Forearm

When performing a distal biceps tendon repair, which of the following complications is most specifically associated with a two-incision technique compared to a single anterior incision approach?

. Lateral antebrachial cutaneous nerve neuropraxia
. Posterior interosseous nerve injury
. Radioulnar synostosis
. Rerupture of the tendon
. Superficial radial nerve injury

Correct Answer & Explanation

. Radioulnar synostosis

Explanation

The two-incision technique for distal biceps repair carries a higher risk of heterotopic ossification and radioulnar synostosis due to violation of the interosseous membrane. The single-incision technique has a higher risk of lateral antebrachial cutaneous nerve (LABC) injury.

Question 1111

Topic: Elbow & Forearm

The primary pathologic process underlying lateral epicondylitis is best described histologically as which of the following?

. Angiofibroblastic tendinosis
. Acute neutrophilic inflammation
. Granulomatous inflammation
. Fibrinoid necrosis
. Chondroid metaplasia

Correct Answer & Explanation

. Angiofibroblastic tendinosis

Explanation

Lateral epicondylitis is a degenerative condition of the extensor carpi radialis brevis (ECRB) origin, not an acute inflammatory process. Histologically, it is characterized by angiofibroblastic tendinosis (hyperplasia of fibroblasts and disorganized collagen).

Question 1112

Topic: Elbow & Forearm

A 35-year-old male presents with a persistent radial nerve palsy following a humerus fracture sustained 12 months ago. He has failed conservative management and is scheduled for tendon transfer surgery. Which of the following describes the most appropriate standard set of tendon transfers to restore wrist, finger, and thumb extension?

. Pronator teres to ECRB, FCU to EDC, Palmaris longus to EPL
. Pronator teres to ECRL, FCR to EDC, Palmaris longus to EPL
. Pronator teres to ECRB, FCR to EDC, Palmaris longus to EPL
. FCR to ECRB, FCU to EDC, Pronator teres to EPL
. FCU to ECRB, FCR to EDC, Palmaris longus to EPL

Correct Answer & Explanation

. Pronator teres to ECRB, FCR to EDC, Palmaris longus to EPL

Explanation

The classic set of transfers for radial nerve palsy is the Pronator Teres (PT) to Extensor Carpi Radialis Brevis (ECRB) for wrist extension, Flexor Carpi Radialis (FCR) to Extensor Digitorum Communis (EDC) for finger extension, and Palmaris Longus (PL) to Extensor Pollicis Longus (EPL) for thumb extension. Transferring PT to ECRB rather than ECRL is preferred to prevent a radial deviation moment with wrist extension. FCR is often preferred over FCU for finger extension as preserving the FCU provides better ulnar-sided wrist stability, especially in power grip.

Question 1113

Topic: Elbow & Forearm

In a patient undergoing tendon transfer for a high radial nerve palsy (e.g., standard Jones or Brand transfer), which muscle-tendon unit is universally utilized to restore functional wrist extension?

. Flexor carpi ulnaris
. Flexor carpi radialis
. Pronator teres
. Palmaris longus
. Flexor digitorum superficialis

Correct Answer & Explanation

. Pronator teres

Explanation

The pronator teres (PT) is universally utilized to restore wrist extension in radial nerve palsy. It is transferred to the extensor carpi radialis brevis (ECRB) because the ECRB is centrally located and provides balanced wrist extension without severe radial or ulnar deviation. The other muscles mentioned are typically utilized to restore finger extension or thumb extension.

Question 1114

Topic: Elbow & Forearm

A 50-year-old male with an irreversible high radial nerve palsy is undergoing tendon transfers. The surgeon elects to perform a Boyes transfer rather than the standard set of tendon transfers. Which of the following specific tendon transfers is a defining feature of the Boyes technique for restoring finger extension?

. Flexor carpi ulnaris (FCU) to Extensor digitorum communis (EDC)
. Pronator teres (PT) to Extensor carpi radialis brevis (ECRB)
. Flexor digitorum superficialis (FDS) of the long finger to the EDC
. Flexor carpi radialis (FCR) to the EDC
. Palmaris longus (PL) to the Extensor pollicis longus (EPL)

Correct Answer & Explanation

. Flexor digitorum superficialis (FDS) of the long finger to the EDC

Explanation

In the treatment of high radial nerve palsy, standard tendon transfers (e.g., Jones or modified standard) often use the FCR or FCU for finger extension. The Boyes transfer is uniquely characterized by utilizing the Flexor Digitorum Superficialis (FDS) of the long finger transferred through the interosseous membrane to the EDC to restore finger extension. PT to ECRB is common to almost all methods to restore wrist extension.

Question 1115

Topic: Elbow & Forearm

A patient presents with a chronic high radial nerve palsy following a humerus fracture and elects to undergo tendon transfer surgery to restore wrist and finger extension. Which of the following is the most widely accepted standard tendon transfer to restore wrist extension in this scenario?

. Flexor carpi ulnaris (FCU) to extensor digitorum communis (EDC)
. Flexor carpi radialis (FCR) to extensor digitorum communis (EDC)
. Pronator teres (PT) to extensor carpi radialis brevis (ECRB)
. Pronator teres (PT) to extensor carpi radialis longus (ECRL)
. Palmaris longus (PL) to extensor pollicis longus (EPL)

Correct Answer & Explanation

. Pronator teres (PT) to extensor carpi radialis brevis (ECRB)

Explanation

In the standard set of tendon transfers for a high radial nerve palsy, the pronator teres (PT) is transferred to the extensor carpi radialis brevis (ECRB) to restore wrist extension. The ECRB is preferred over the ECRL because it inserts centrally at the base of the third metacarpal, providing pure wrist extension without the radial deviation seen when transferring to the ECRL.

Question 1116

Topic: Elbow & Forearm

A 40-year-old male sustains a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, and coronoid fracture). During surgical reconstruction, after fixation of the coronoid and replacement of the comminuted radial head, the elbow remains unstable in extension and supination. What is the next most appropriate step in the surgical sequence?

. Application of an articulated dynamic external fixator
. Repair of the lateral ulnar collateral ligament (LUCL) to the lateral epicondyle
. Repair of the anterior bundle of the medial collateral ligament (MCL)
. Transarticular pinning of the ulnohumeral joint
. Excise the coronoid fragment to remove the mechanical block

Correct Answer & Explanation

. Repair of the lateral ulnar collateral ligament (LUCL) to the lateral epicondyle

Explanation

The standard algorithm for a terrible triad injury works from deep to superficial and typically involves restoring the anterior buttress (coronoid), restoring the radiocapitellar contact (radial head fix/replace), and then restoring the lateral stabilizing structures by repairing the LUCL to the lateral epicondyle. If the elbow remains unstable after LUCL repair, MCL repair or a hinged external fixator is considered.

Question 1117

Topic: Elbow & Forearm

In a patient with an irreversible high radial nerve palsy, which of the following is the most standard and biomechanically reliable tendon transfer to restore wrist extension?

. Flexor carpi ulnaris (FCU) to extensor carpi radialis brevis (ECRB)
. Pronator teres (PT) to extensor carpi radialis longus (ECRL)
. Pronator teres (PT) to extensor carpi radialis brevis (ECRB)
. Flexor digitorum superficialis (FDS) to extensor digitorum communis (EDC)
. Palmaris longus (PL) to extensor pollicis longus (EPL)

Correct Answer & Explanation

. Pronator teres (PT) to extensor carpi radialis brevis (ECRB)

Explanation

The classic transfer for restoring wrist extension in a radial nerve palsy is the Pronator Teres (PT) to the Extensor Carpi Radialis Brevis (ECRB). The ECRB is chosen over the ECRL because its central insertion at the base of the third metacarpal provides balanced wrist extension, whereas ECRL insertion results in radial deviation.

Question 1118

Topic: Elbow & Forearm
A 35-year-old female sustains a Monteggia fracture-dislocation. According to the Bado classification, a Type I injury consists of an ulnar diaphyseal fracture combined with which of the following?
. Anterior dislocation of the radial head
. Posterior dislocation of the radial head
. Lateral dislocation of the radial head
. Fracture of the radial head without dislocation
. Distal radioulnar joint dislocation

Correct Answer & Explanation

. Anterior dislocation of the radial head

Explanation

The Bado classification describes Monteggia fractures based on the direction of radial head dislocation. Type I (most common) is an anterior dislocation of the radial head with an anteriorly angulated ulnar fracture. Type II is posterior. Type III is lateral. Type IV involves fractures of both the radius and ulna with an anterior radial head dislocation.

Question 1119

Topic: Elbow & Forearm

A 10-year-old boy with Hereditary Multiple Exostoses (HME) presents with progressive forearm deformity and loss of pronation. Which of the following is the characteristic pattern of forearm dysplasia typically seen in HME?

. Radial shortening, ulnar bowing, and ulnocarpal impaction
. Ulnar shortening, radial bowing, and radial head subluxation
. Equal shortening of the radius and ulna with proximal radioulnar synostosis
. Radial overgrowth with distal radioulnar joint dislocation
. Ulnar overgrowth with proximal radioulnar joint dislocation

Correct Answer & Explanation

. Ulnar shortening, radial bowing, and radial head subluxation

Explanation

In HME, the distal ulna contributes significantly to longitudinal growth and is disproportionately affected by osteochondromas. This results in relative ulnar shortening, secondary radial bowing, and eventual radial head subluxation.

Question 1120

Topic: Elbow & Forearm

A 14-year-old boy with a known diagnosis of Multiple Hereditary Exostoses (MHE) presents with a progressive deformity of his left forearm. Which of the following is the most typical pattern of forearm deformity expected in this condition?

. Ulnar lengthening with secondary distal radioulnar joint subluxation
. Ulnar shortening, radial bowing, and potential radial head dislocation
. Symmetrical shortening of both the radius and ulna with a neutral wrist alignment
. Primary radial shortening with secondary ulnar bowing and ulnar head dislocation

Correct Answer & Explanation

. Ulnar shortening, radial bowing, and potential radial head dislocation

Explanation

Correct Answer: Ulnar shortening, radial bowing, and potential radial head dislocationIn Multiple Hereditary Exostoses (Osteochondromatosis), forearm deformities are common due to the presence of osteochondromas affecting the distal physes. The distal ulnar physis contributes a larger percentage to the overall length of the ulna compared to the radius. Therefore, an osteochondroma here disproportionately retards ulnar growth, leading to relative ulnar shortening. The continued growth of the tethered radius results in radial bowing, increased ulnar variance (negative), and eventually radial head subluxation or dislocation (Masada classification).

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