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Elbow & Forearm MCQs

Practice Set 16 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 301

Topic: Elbow & Forearm

During radial head replacement in the context of a terrible triad injury, the surgeon must be meticulous to avoid a common complication that can lead to persistent instability or stiffness. What specific intraoperative pitfall is emphasized in the case description regarding radial head replacement?

. A) Incorrect sizing of the radial head implant
. B) Failure to adequately debride the joint
. C) 'Overstuffing' the joint with the radial head prosthesis
. D) Damage to the posterior interosseous nerve
. E) Inadequate cementation of the prosthesis

Correct Answer & Explanation

. C) 'Overstuffing' the joint with the radial head prosthesis

Explanation

Correct Answer: CThe case specifically warns against this pitfall: "The next step would be to prepare and place a radial head replacement, taking care not to 'overstuff' the joint." Overstuffing the joint can lead to increased joint reactive forces, stiffness, pain, and even persistent instability by preventing full reduction or proper tracking of the ulnohumeral joint. While other options are important considerations, 'overstuffing' is explicitly mentioned as a critical point to avoid.

Question 302

Topic: Elbow & Forearm

In the described operative sequence for a terrible triad injury, which of the following steps is performed first to facilitate access to deeper structures like the coronoid and anterior capsule?

. A) Repair of the lateral collateral ligament
. B) Placement of the radial head replacement
. C) Excision of the radial head fragments
. D) Reduction and fixation of the coronoid fracture
. E) Repair of the medial collateral ligament

Correct Answer & Explanation

. C) Excision of the radial head fragments

Explanation

Correct Answer: CThe case clearly outlines the initial steps: "I would excise the radial head fragments first, which would give me access to the coronoid and anterior capsule." Removing the radial head fragments provides an unobstructed view and working space for addressing the coronoid fracture and anterior capsule repair, which are crucial for ulnohumeral stability.

Question 303

Topic: Elbow & Forearm

Which radiographic sign is most indicative of a radial head dislocation in the context of an ulnar fracture?

. Widening of the radiocapitellar joint space
. Disruption of the radial head-capitellum alignment on all views
. Presence of fat pads in the elbow joint
. Anterior humeral line not intersecting the capitellum
. Increased carrying angle

Correct Answer & Explanation

. Disruption of the radial head-capitellum alignment on all views

Explanation

Correct Answer: BThe definitive radiographic sign of radial head dislocation is thedisruption of the radial head-capitellum alignment on all views(AP, lateral, and obliques if needed). A line drawn through the center of the radial shaft should always pass through the center of the capitellum, regardless of elbow flexion or forearm rotation. If this capitellar-radial head line does not intersect the capitellum, radial head dislocation is present. While fat pads indicate an effusion (suggesting injury), and an abnormal anterior humeral line suggests supracondylar or condylar fractures, only direct visualization of the radiocapitellar relationship confirms dislocation of the radial head. Widening of the joint space can be a sign but is less definitive than complete disruption of alignment.

Question 304

Topic: Elbow & Forearm

A patient undergoes ORIF for a Monteggia Type II fracture. The ulnar fracture is stably fixed. However, the radial head remains persistently dislocated posteriorly. What is the most likely cause of this persistent dislocation?

. Malreduction of the ulnar fracture
. Rupture of the lateral collateral ligament complex
. Interposition of the torn annular ligament or joint capsule
. Development of heterotopic ossification
. Incorrect choice of implant for ulnar fixation

Correct Answer & Explanation

. Interposition of the torn annular ligament or joint capsule

Explanation

Correct Answer: CEven after stable anatomical reduction and fixation of the ulnar fracture, persistent dislocation of the radial head can occur. The most common cause, especially in the context of the radial head not spontaneously reducing, is theinterposition of soft tissues within the radiocapitellar joint. The torn annular ligament or a portion of the joint capsule can become entrapped, creating a mechanical block to reduction. While malreduction of the ulna can prevent radial head reduction, the question specifies the ulna is 'stably fixed.' Rupture of the lateral collateral ligament complex is possible but less likely to cause an irreducible dislocation compared to mechanical blockage. Heterotopic ossification is a late complication, and implant choice doesn't directly cause irreducible dislocation if the ulna is well-fixed.

Question 305

Topic: Elbow & Forearm

A 42-year-old female sustains a terrible triad injury of the elbow. Operative intervention is planned. Which of the following represents the most widely accepted surgical sequence for restoring stability?

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

Correct Answer & Explanation

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

Explanation

The standard surgical algorithm for terrible triad injuries begins with a deep-to-superficial repair. This involves coronoid fixation or anterior capsule reattachment, followed by radial head fixation or arthroplasty, and finally lateral collateral ligament (LCL) repair.

Question 306

Topic: Elbow & Forearm

During the repair of the lateral ulnar collateral ligament (LUCL) in a terrible triad injury, identifying the correct isometric point on the humerus is critical to prevent joint stiffness or instability. Where is the anatomical origin of the LUCL?

. The anterior aspect of the lateral epicondyle
. The isometric center of the capitellum
. The lateral supracondylar ridge
. The posterior aspect of the capitellum
. The non-articulating surface of the radial head

Correct Answer & Explanation

. The isometric center of the capitellum

Explanation

The LUCL originates at the isometric center of the capitellum on the lateral epicondyle and inserts on the supinator crest of the ulna. Proper isometric placement of the humeral anchor is essential to maintain uniform ligament tension throughout the arc of elbow motion.

Question 307

Topic: Elbow & Forearm

During a terrible triad repair, the surgeon replaces a highly comminuted radial head with a metallic prosthesis. Postoperatively, radiographs show widening of the lateral ulnohumeral joint space. What is the most likely consequence of this specific technical error?

. Early capitellar osteonecrosis and limited elbow flexion
. Ulnar nerve subluxation
. Recurrent posterolateral rotatory instability
. Symptomatic proximal radioulnar synostosis
. Subcoracoid impingement

Correct Answer & Explanation

. Early capitellar osteonecrosis and limited elbow flexion

Explanation

Widening of the lateral ulnohumeral joint indicates overstuffing of the radiocapitellar joint by choosing a radial head prosthesis that is too long or thick. This increases pressure on the capitellum, leading to early cartilage wear, restricted flexion, and potential capitellar osteonecrosis.

Question 308

Topic: Elbow & Forearm

A surgeon is performing open reduction and internal fixation (ORIF) of a Bado Type I Monteggia fracture in an adult. After achieving anatomic reduction and rigid plate fixation of the ulna, the radial head remains anteriorly dislocated. What is the most appropriate next step?

. Perform a closed reduction of the radial head using hyperpronation
. Osteotomize the ulna to shorten it
. Open exploration of the radiocapitellar joint to clear interposed tissue
. Perform a radial head excision
. Accept the position and immobilize in 120 degrees of flexion

Correct Answer & Explanation

. Open exploration of the radiocapitellar joint to clear interposed tissue

Explanation

In a Monteggia fracture, the radial head usually reduces spontaneously once the ulna is anatomically restored. If it remains dislocated, open exploration of the radiocapitellar joint is required to remove interposed structures, most commonly the annular ligament or joint capsule.

Question 309

Topic: Elbow & Forearm

When managing a terrible triad injury, a surgeon chooses an extensile lateral approach utilizing the Kaplan interval to access both the radial head and the coronoid. Which of the following nerve structures is at greatest risk when extending this interval distally?

. Ulnar nerve
. Superficial radial nerve
. Posterior interosseous nerve (PIN)
. Anterior interosseous nerve (AIN)
. Musculocutaneous nerve

Correct Answer & Explanation

. Posterior interosseous nerve (PIN)

Explanation

The Kaplan interval utilizes the plane between the extensor digitorum communis (EDC) and the extensor carpi radialis brevis (ECRB). Extending this interval distally places the posterior interosseous nerve (PIN) at significant risk as it crosses the proximal radius within the supinator muscle.

Question 310

Topic: Elbow & Forearm

An 8-year-old child presents with a progressive cubitus valgus deformity and tardy ulnar nerve palsy. Radiographs reveal a chronic anteriorly dislocated radial head and a malunited proximal ulna fracture sustained 18 months ago. What is the most appropriate surgical treatment?

. Radial head excision alone
. In situ ulnar nerve transposition
. Ulnar osteotomy with open reduction of the radial head
. Observation until skeletal maturity
. Radiocapitellar arthrodesis

Correct Answer & Explanation

. Ulnar osteotomy with open reduction of the radial head

Explanation

In a child with a chronic Monteggia fracture-dislocation, the standard treatment involves a corrective opening-wedge osteotomy of the ulna to restore length and alignment. This is combined with open reduction of the radial head, as radial head excision is contraindicated in growing children.

Question 311

Topic: Elbow & Forearm

When performing surgical reconstruction for a terrible triad injury of the elbow, which of the following represents the most widely accepted sequential order of repair?

. LCL complex, radial head, coronoid, MCL
. MCL, coronoid, radial head, LCL complex
. Coronoid, radial head, LCL complex, MCL (if needed)
. Radial head, LCL complex, coronoid, MCL
. Coronoid, LCL complex, radial head, MCL

Correct Answer & Explanation

. Coronoid, radial head, LCL complex, MCL (if needed)

Explanation

The standard protocol for terrible triad reconstruction is 'inside-out'. This begins with fixing the coronoid, followed by the radial head (fixation or arthroplasty), and then the lateral collateral ligament (LCL) complex. The MCL or a hinged external fixator is addressed last only if residual instability exists.

Question 312

Topic: Elbow & Forearm

To restore posterolateral rotatory stability during terrible triad surgery, the lateral ulnar collateral ligament (LUCL) must be repaired. Where is the correct distal insertion site of the LUCL?

. Radial tuberosity
. Coronoid process
. Supinator crest of the ulna
. Olecranon tip
. Lesser sigmoid notch

Correct Answer & Explanation

. Supinator crest of the ulna

Explanation

The LUCL originates at the lateral epicondyle and inserts distally on the supinator crest of the proximal ulna. Restoring this footprint is critical to preventing posterolateral rotatory instability.

Question 313

Topic: Elbow & Forearm

During surgery for a terrible triad injury, the radial head is found to be highly comminuted with more than 3 fragments and is deemed irreparable. What is the most appropriate management of the radial head?

. Radial head excision alone
. Metallic radial head arthroplasty
. Silicone radial head replacement
. Primary radiocapitellar fusion
. Allograft radial head transplantation

Correct Answer & Explanation

. Metallic radial head arthroplasty

Explanation

In the setting of a terrible triad, radial head excision alone leads to severe instability because the primary collateral ligaments are disrupted. Metallic radial head arthroplasty is indicated to restore the lateral column buttress.

Question 314

Topic: Elbow & Forearm

When evaluating pediatric elbow radiographs for a subtle Monteggia variant, which radiographic line is critical to assess to rule out a radial head dislocation?

. Radiocapitellar line
. Anterior humeral line
. Baumann's angle
. Tear drop sign
. Metaphyseal-diaphyseal angle

Correct Answer & Explanation

. Radiocapitellar line

Explanation

The radiocapitellar line should bisect the capitellum on every radiographic view, irrespective of the degree of elbow flexion. Failure of this line to intersect the capitellum indicates a radial head dislocation.

Question 315

Topic: Elbow & Forearm

When utilizing a bone anchor to repair the avulsed lateral collateral ligament complex during a terrible triad reconstruction, where is the exact anatomic isometric origin on the lateral humerus?

. At the center of rotation on the lateral epicondyle, anterior to the capitellum
. At the isometric center of rotation on the lateral epicondyle, located at the axis of the capitellum
. At the insertion of the brachioradialis
. Directly on the lateral supracondylar ridge
. On the posterior non-articulating aspect of the trochlea

Correct Answer & Explanation

. At the isometric center of rotation on the lateral epicondyle, located at the axis of the capitellum

Explanation

The LUCL originates at the isometric point on the lateral epicondyle, which corresponds to the central axis of elbow rotation (capitellum). Proper isometric placement ensures the ligament maintains appropriate tension throughout the flexion-extension arc.

Question 316

Topic: Elbow & Forearm

A 45-year-old female presents with a terrible triad injury of the elbow. During surgical reconstruction, what is the most widely accepted sequential order of repair to restore elbow stability?

. Lateral ulnar collateral ligament (LUCL) repair, radial head fixation, coronoid fixation
. Radial head fixation, coronoid fixation, medial collateral ligament (MCL) repair
. Coronoid fixation, radial head fixation or arthroplasty, LUCL repair
. LUCL repair, coronoid fixation, radial head arthroplasty
. Coronoid fixation, MCL repair, LUCL repair, radial head fixation

Correct Answer & Explanation

. Coronoid fixation, radial head fixation or arthroplasty, LUCL repair

Explanation

The standard surgical sequence for a terrible triad injury works deep to superficial: fixing the coronoid/anterior capsule first, followed by the radial head, and finally repairing the LUCL. Reassessing stability afterward determines if MCL repair or an external fixator is needed.

Question 317

Topic: Elbow & Forearm

A 50-year-old male undergoes radial head arthroplasty as part of a terrible triad reconstruction. Postoperatively, he has persistent medial elbow pain, a 15-degree loss of terminal flexion, and widening of the medial joint line on AP radiographs. What is the most likely iatrogenic cause of these findings?

. Undersizing the radial head prosthesis
. Overstuffing the radiocapitellar joint
. Failure to repair the MCL
. Placement of the LUCL suture anchors anterior to the isometric point
. Entrapment of the ulnar nerve

Correct Answer & Explanation

. Overstuffing the radiocapitellar joint

Explanation

Overstuffing the radiocapitellar joint with a radial head prosthesis that is too long causes increased pressure on the capitellum, restricted flexion, and gaping of the medial radioulnar joint due to tension on the medial structures.

Question 318

Topic: Elbow & Forearm

During the lateral approach for a terrible triad injury, the surgeon decides to use the Kaplan interval instead of the Kocher interval to access the radial head. Between which two muscles does the Kaplan approach pass, and what structure is at higher risk compared to the Kocher approach?

. ECU and anconeus; posterior interosseous nerve (PIN)
. EDC and ECRB; posterior interosseous nerve (PIN)
. ECU and anconeus; lateral ulnar collateral ligament (LUCL)
. EDC and ECRB; lateral ulnar collateral ligament (LUCL)
. Brachioradialis and ECRL; superficial radial nerve

Correct Answer & Explanation

. EDC and ECRB; posterior interosseous nerve (PIN)

Explanation

The Kaplan approach utilizes the interval between the extensor digitorum communis (EDC) and the extensor carpi radialis brevis (ECRB). It places the PIN at greater risk distally compared to the Kocher approach (ECU and anconeus), though it generally preserves the LUCL better.

Question 319

Topic: Elbow & Forearm

When repairing the lateral ulnar collateral ligament (LUCL) during a terrible triad reconstruction, anatomic placement of the suture anchor on the humerus is crucial. What is the correct anatomic origin of the LUCL?

. The medial epicondyle, anterior to the flexor pronator mass
. The lateral epicondyle, at the isometric center of capitellar rotation
. The supinator crest of the proximal ulna
. The lateral supracondylar ridge, proximal to the ECRL origin
. The radial tuberosity, deep to the biceps tendon

Correct Answer & Explanation

. The lateral epicondyle, at the isometric center of capitellar rotation

Explanation

The LUCL originates on the lateral epicondyle at the isometric point corresponding to the center of capitellar rotation. It inserts distally onto the supinator crest of the ulna.

Question 320

Topic: Elbow & Forearm

A surgeon approaches a complex proximal ulna fracture with radial head dislocation using the Boyd approach. Which of the following complications is historically highly associated with the extensive muscle stripping required by this approach?

. Superficial radial nerve neuroma
. Triceps avulsion
. Proximal radioulnar synostosis
. Ulnar nerve palsy
. Avascular necrosis of the capitellum

Correct Answer & Explanation

. Proximal radioulnar synostosis

Explanation

The Boyd approach exposes the proximal ulna and radius by elevating the supinator and anconeus off the ulna. This extensive subperiosteal stripping in the region of the interosseous membrane carries a notoriously high risk of developing proximal radioulnar synostosis.

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