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Elbow & Forearm MCQs

Practice Set 30 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 581

Topic: Elbow & Forearm

A 35-year-old man falls on his outstretched arm, sustaining an elbow dislocation with associated radial head and coronoid process fractures. After operative restoration of the coronoid and radial head, the elbow remains unstable in extension. What is the most appropriate next step in management?

. Repair the lateral ulnar collateral ligament (LUCL).
. Repair the medial collateral ligament (MCL).
. Apply an external fixator.
. Perform a common extensor origin repair.
. Cross-pin the radiocapitellar joint.

Correct Answer & Explanation

. Repair the lateral ulnar collateral ligament (LUCL).

Explanation

The standard surgical sequence for a terrible triad injury involves coronoid fixation, radial head repair or replacement, and LUCL repair. If the elbow remains unstable after these steps, MCL repair or a hinged external fixator may be considered.

Question 582

Topic: Elbow & Forearm

A 45-year-old man undergoes volar locked plating for a displaced distal radius fracture. Six months later, he presents with an inability to actively extend his thumb interphalangeal joint. This complication is most likely due to rupture of which structure?

. Extensor pollicis longus (EPL).
. Flexor pollicis longus (FPL).
. Extensor carpi radialis brevis (ECRB).
. Extensor indicis proprius (EIP).
. Posterior interosseous nerve (PIN).

Correct Answer & Explanation

. Extensor pollicis longus (EPL).

Explanation

Prominent dorsal screws extending past the dorsal cortex in a volar plate construct are a common cause of extensor tendon irritation and EPL rupture. The EPL is particularly vulnerable as it curves around Lister's tubercle.

Question 583

Topic: Elbow & Forearm

A 28-year-old woman falls from a height, sustaining a highly comminuted, unsalvageable radial head fracture and positive ulnar variance at the wrist with distal radioulnar joint (DRUJ) instability. What is the most appropriate management of the radial head in this setting?

. Radial head excision alone.
. Radial head excision with distal radioulnar joint pinning.
. Radial head arthroplasty.
. Radial head arthroplasty and distal radioulnar joint pinning.
. Open reduction and internal fixation.

Correct Answer & Explanation

. Radial head arthroplasty and distal radioulnar joint pinning.

Explanation

This is an Essex-Lopresti injury involving longitudinal radioulnar dissociation. Excision of the radial head without replacement leads to proximal radial migration; therefore, radial head arthroplasty combined with DRUJ stabilization is required.

Question 584

Topic: Elbow & Forearm

A 40-year-old woman falls on her outstretched hand and sustains a capitellum fracture. Radiographs show a large anterior osteochondral fragment that includes the capitellum and the lateral half of the trochlea. This describes which type of fracture pattern?

. Hahn-Steinthal (Type 1).
. Kocher-Lorenz (Type 2).
. Broberg-Morrey (Type 3).
. Type 4 (McKee modification).
. Osborne-Cotterill.

Correct Answer & Explanation

. Type 4 (McKee modification).

Explanation

A Type 4 capitellum fracture (McKee modification of the Bryan and Morrey classification) involves a coronal shear fracture that includes the capitellum and the lateral half of the trochlea. It often requires stable anatomic fixation to prevent post-traumatic arthrosis.

Question 585

Topic: Elbow & Forearm

A 35-year-old female presents with a 'terrible triad' injury of the elbow consisting of an elbow dislocation, radial head fracture, and coronoid fracture. What is the standard sequence of repair during surgical reconstruction?

. Coronoid fixation, radial head repair/replacement, lateral ulnar collateral ligament repair
. Radial head repair/replacement, coronoid fixation, lateral ulnar collateral ligament repair
. Lateral ulnar collateral ligament repair, coronoid fixation, radial head repair
. Coronoid fixation, lateral ulnar collateral ligament repair, radial head repair
. Radial head repair/replacement, lateral ulnar collateral ligament repair, coronoid fixation

Correct Answer & Explanation

. Coronoid fixation, radial head repair/replacement, lateral ulnar collateral ligament repair

Explanation

The standard surgical sequence for terrible triad injuries addresses structures from deep to superficial: coronoid fixation first, followed by radial head repair or replacement, and finally lateral ulnar collateral ligament (LUCL) repair.

Question 586

Topic: Elbow & Forearm

A 40-year-old weightlifter undergoes an anterior single-incision repair of a distal biceps tendon rupture. Postoperatively, he reports numbness over the lateral aspect of his forearm. Which nerve was most likely injured during the procedure?

. Superficial radial nerve
. Median nerve
. Posterior interosseous nerve (PIN)
. Lateral antebrachial cutaneous nerve
. Medial antebrachial cutaneous nerve

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve

Explanation

The lateral antebrachial cutaneous nerve (LACN) is the terminal sensory branch of the musculocutaneous nerve and courses near the cephalic vein in the lateral forearm. It is the most commonly injured nerve during a single-incision anterior distal biceps repair.

Question 587

Topic: Elbow & Forearm

A 35-year-old man falls on an outstretched hand, sustaining a 'terrible triad' injury of the elbow. During surgical reconstruction, what is the generally recommended sequence of repair to restore elbow stability?

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

Correct Answer & Explanation

. Coronoid, then radial head, then lateral collateral ligament complex

Explanation

The standard surgical sequence for a terrible triad injury is repairing deep to superficial. This involves addressing the coronoid first, followed by the radial head (repair or replace), and finally the lateral collateral ligament complex.

Question 588

Topic: Elbow & Forearm

In the surgical management of a "terrible triad" injury of the elbow, which of the following represents the most accepted sequence of repair after exposing the joint?

. Radial head repair, LCL repair, coronoid fixation
. Coronoid fixation, LCL repair, radial head repair
. Coronoid fixation, radial head repair, LCL repair
. LCL repair, radial head repair, coronoid fixation
. Radial head repair, coronoid fixation, LCL repair

Correct Answer & Explanation

. Coronoid fixation, LCL repair, radial head repair

Explanation

Standard protocol for the terrible triad includes coronoid fixation, radial head repair or replacement, followed by lateral collateral ligament (LCL) repair. This inside-out sequence restores anterior skeletal stability before addressing the lateral ligamentous restraints.

Question 589

Topic: Elbow & Forearm

A 35-year-old woman sustains a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, and coronoid fracture). Surgical fixation is planned. What is the generally accepted sequence of repair to restore stability?

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

Correct Answer & Explanation

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

Explanation

The standard surgical algorithm for a terrible triad injury proceeds from deep to superficial: coronoid fixation first, followed by the radial head, and finally the lateral collateral ligament (LCL) complex. MCL repair is only considered if the elbow remains grossly unstable after these steps.

Question 590

Topic: Elbow & Forearm

A 30-year-old male presents with elbow clicking and apprehension when pushing up from a chair. Posterolateral rotatory instability (PLRI) is diagnosed. The primary deficient structure originates on the lateral epicondyle and inserts on which of the following structures?

. Coronoid process of the ulna
. Radial tuberosity
. Supinator crest of the ulna
. Olecranon tip
. Annular ligament directly

Correct Answer & Explanation

. Supinator crest of the ulna

Explanation

Posterolateral rotatory instability (PLRI) results from insufficiency 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 the primary restraint to varus and external rotatory stress.

Question 591

Topic: Elbow & Forearm

A patient with rheumatoid arthritis presents with an inability to actively extend their thumb interphalangeal joint. Rupture of the extensor pollicis longus (EPL) tendon is suspected. The EPL tendon normally routes around Lister's tubercle, separating which two dorsal extensor compartments?

. Compartments 1 and 2
. Compartments 2 and 3
. Compartments 3 and 4
. Compartments 4 and 5
. Compartments 1 and 3

Correct Answer & Explanation

. Compartments 2 and 3

Explanation

Lister's tubercle acts as a mechanical pulley for the EPL tendon, which resides in the 3rd dorsal compartment. It separates the 2nd dorsal compartment (containing the ECRL and ECRB) from the 3rd compartment.

Question 592

Topic: Elbow & Forearm

The distal biceps tendon normally inserts on the radial tuberosity. To maximize supination strength during a surgical repair of a ruptured tendon, it should be reattached to which specific footprint?

. Anterior aspect of the radial tuberosity
. Ulnar aspect of the coronoid process
. Posterior aspect of the radial tuberosity
. Lateral aspect of the radial tuberosity
. Distal pole of the radial tuberosity

Correct Answer & Explanation

. Posterior aspect of the radial tuberosity

Explanation

The native distal biceps tendon inserts on the ulnar/posterior aspect of the radial tuberosity. Reattaching it as posterior as possible maximizes the supination moment arm and restores functional strength.

Question 593

Topic: Elbow & Forearm

A 28-year-old gymnast sustains an elbow dislocation. After closed reduction, she has persistent posterolateral rotatory instability (PLRI). Deficiency of which of the following structures is the primary cause of this instability?

. Radial collateral ligament
. Lateral ulnar collateral ligament
. Annular ligament
. Accessory collateral ligament
. Anterior bundle of the medial collateral ligament

Correct Answer & Explanation

. Lateral ulnar collateral ligament

Explanation

The lateral ulnar collateral ligament (LUCL) is the primary stabilizer against posterolateral rotatory instability (PLRI) of the elbow. It originates from the lateral epicondyle and inserts on the supinator crest of the ulna.

Question 594

Topic: Elbow & Forearm

A patient presents with posterolateral rotatory instability (PLRI) of the elbow following a dislocation. This condition is primarily caused by insufficiency of the lateral ulnar collateral ligament (LUCL). Where does the LUCL anatomically insert?

. Radial neck
. Annular ligament
. Supinator crest of the ulna
. Coronoid process of the ulna
. Olecranon process

Correct Answer & Explanation

. Supinator crest of the ulna

Explanation

The lateral ulnar collateral ligament (LUCL) is the primary restraint to posterolateral rotatory instability of the elbow. It originates on the lateral epicondyle and inserts on the supinator crest of the proximal ulna.

Question 595

Topic: Elbow & Forearm

During the proximal portion of the volar (Henry) approach to the forearm, supination of the forearm is performed to protect a major nerve. Which muscle's insertion is stripped and elevated to expose the proximal radius, and what is the anatomical relationship of the at-risk nerve to this muscle?

. Supinator; the nerve lies within the substance of the muscle between its superficial and deep heads.
. Pronator teres; the nerve lies superficial to its ulnar border.
. Biceps brachii; the nerve lies deep to its aponeurosis.
. Brachioradialis; the nerve lies medial to its tendon.
. Flexor digitorum superficialis; the nerve lies deep to its radial head.

Correct Answer & Explanation

. Supinator; the nerve lies within the substance of the muscle between its superficial and deep heads.

Explanation

In the volar (Henry) approach to the proximal radius, the supinator muscle is elevated to expose the bone. Supinating the forearm protects the posterior interosseous nerve (PIN), which safely moves laterally away from the surgical field as it courses between the superficial and deep heads of the supinator.

Question 596

Topic: Elbow & Forearm

Posterolateral rotatory instability (PLRI) of the elbow is primarily caused by insufficiency of the lateral ulnar collateral ligament (LUCL). What is the precise insertion of the LUCL?

. Radial neck
. Supinator crest of the ulna
. Sublime tubercle
. Annular ligament
. Lesser sigmoid notch

Correct Answer & Explanation

. Supinator crest of the ulna

Explanation

The LUCL originates on the lateral epicondyle of the humerus, blends with the annular ligament, and inserts on the supinator crest of the proximal ulna. Its insufficiency is the primary lesion in posterolateral rotatory instability.

Question 597

Topic: Elbow & Forearm

The lateral ulnar collateral ligament (LUCL) is the primary stabilizer against posterolateral rotatory instability (PLRI) of the elbow. Where does the LUCL typically insert?

. Olecranon tip
. Radial tuberosity
. Supinator crest of the ulna
. Coronoid process
. Lateral epicondyle

Correct Answer & Explanation

. Lateral epicondyle

Explanation

The LUCL originates from the lateral epicondyle of the humerus and inserts onto the supinator crest of the proximal ulna. Disruption of this ligament leads to posterolateral rotatory instability.

Question 598

Topic: Elbow & Forearm

A 2-year-old girl presents with her arm held closely to her side in slight flexion and pronation. Her father reports pulling her by the arm to prevent a fall. Radiographs are normal. What anatomical structure is subluxated?

. Annular ligament
. Quadrate ligament
. Radial collateral ligament
. Ulnar collateral ligament
. Interosseous membrane

Correct Answer & Explanation

. Annular ligament

Explanation

Nursemaid's elbow is a radial head subluxation caused by axial traction on a pronated and extended forearm. The annular ligament slips over the radial head and becomes interposed between the radius and the capitellum.

Question 599

Topic: Elbow & Forearm

In a patient with a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, coronoid fracture), what is the most appropriate surgical sequence to restore elbow stability?

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

Correct Answer & Explanation

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

Explanation

The standard surgical sequence for a terrible triad injury works deep to superficial. This involves fixation of the coronoid first, followed by radial head repair or replacement, and finally repair of the lateral collateral ligament (LCL) complex.

Question 600

Topic: Elbow & Forearm

A patient falls on an outstretched hand and complains of lateral elbow pain. Radiographs show a comminuted radial head fracture. There is also marked tenderness over the distal radioulnar joint (DRUJ). If the radial head is excised without replacement, what complication is most likely to occur?

. Proximal migration of the radius
. Heterotopic ossification of the elbow
. Ulnar nerve palsy
. Avascular necrosis of the capitellum
. Nonunion of the ulna

Correct Answer & Explanation

. Proximal migration of the radius

Explanation

The patient has an Essex-Lopresti lesion, consisting of a radial head fracture, interosseous membrane disruption, and DRUJ injury. Excision of the radial head without prosthetic replacement in this setting will lead to profound proximal radial migration and chronic wrist pain.

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