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9. Shoulder and Elbow MCQs

Practice Set 39 of 197

This practice set contains high-yield board review questions covering key concepts in 9. Shoulder and Elbow. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 761

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 762

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 763

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 764

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 765

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 766

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 767

Topic: 9. Shoulder and Elbow

Which of the following is the most common complication following surgical treatment of a terrible triad injury of the elbow?

. Post-traumatic elbow stiffness
. Nonunion of the radial head
. Symptomatic hardware requiring removal
. Ulnar neuropathy
. Recurrent posterolateral rotatory instability

Correct Answer & Explanation

. Post-traumatic elbow stiffness

Explanation

Post-traumatic stiffness is the most common complication following the surgical treatment of terrible triad injuries. To combat this, achieving a stable repair that permits early active motion is a primary surgical goal.

Question 768

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 769

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 770

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 771

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 772

Topic: 9. Shoulder and Elbow

A surgeon performs a radial head arthroplasty for a terrible triad injury but accidentally sizes the implant too large. Which of the following complications is most likely to occur as a direct result?

. Capitellar wear and loss of elbow flexion
. Proximal radioulnar joint dissociation
. Ulnar nerve impingement
. Recurrent posterolateral rotatory instability
. Coronoid nonunion

Correct Answer & Explanation

. Capitellar wear and loss of elbow flexion

Explanation

Oversizing or 'overstuffing' the radiocapitellar joint increases joint contact pressures significantly. This leads to accelerated capitellar wear, pain, and restricted elbow range of motion, particularly in flexion.

Question 773

Topic: 9. Shoulder and Elbow

Following fixation of the coronoid and radial head, and repair of the LCL in a terrible triad injury, the elbow subluxates posteriorly when extended past 30 degrees. What is the most appropriate next intraoperative step?

. Perform a corrective ulnar osteotomy
. Repair the medial collateral ligament (MCL) or apply a hinged external fixator
. Remove the radial head prosthesis to relieve tension
. Perform a primary triceps advancement
. Cast the arm in full extension for 6 weeks

Correct Answer & Explanation

. Repair the medial collateral ligament (MCL) or apply a hinged external fixator

Explanation

If the elbow remains unstable after addressing the coronoid, radial head, and LCL, it indicates severe medial-sided injury or gross global instability. The next step is to repair the MCL and/or apply a hinged external fixator.

Question 774

Topic: 9. Shoulder and Elbow

A 10-year-old child presents with a 6-month history of a missed anterior Monteggia fracture. Which of the following physical examination findings is most characteristic of this chronic unreduced state?

. Severe resting pain and intrinsic minus hand
. Loss of terminal elbow flexion and limited forearm pronation
. Fixed cubitus varus deformity
. Progressive ulnar nerve clawing
. Severe radiocarpal arthritis

Correct Answer & Explanation

. Loss of terminal elbow flexion and limited forearm pronation

Explanation

A chronically anteriorly dislocated radial head acts as a mechanical block. This typically restricts terminal elbow flexion and limits full forearm rotation.

Question 775

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 776

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 777

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 778

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 779

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 780

Topic: 9. Shoulder and Elbow

After completing the fixation of the coronoid, radial head, and repairing the LUCL in a terrible triad injury, the elbow remains unstable and continues to dislocate posteriorly at 30 degrees of flexion. What is the most appropriate next step in management?

. Perform a radial nerve release
. Apply an external fixator or repair the medial collateral ligament (MCL)
. Revise the radial head to a larger prosthesis
. Cast the patient in 90 degrees of flexion and maximal supination
. Resect the remaining coronoid to decompress the joint

Correct Answer & Explanation

. Apply an external fixator or repair the medial collateral ligament (MCL)

Explanation

If the elbow remains unstable (specifically tending to dislocate at >30 degrees of flexion) after addressing the coronoid, radial head, and LUCL, the next step is either to repair the MCL or to apply a hinged elbow external fixator to maintain a concentric reduction.

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