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Elbow & Forearm MCQs

Practice Set 44 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 861

Topic: Elbow & Forearm

When performing a lateral ulnar collateral ligament (LUCL) reconstruction for posterolateral rotatory instability (PLRI) of the elbow, accurate graft placement is critical. Where is the precise isometric origin of the LUCL on the lateral epicondyle to ensure stability and uniform tension throughout the elbow's range of motion?

. At the geometric center of the capitellum's axis of rotation
. Proximal and posterior to the lateral epicondyle
. Directly on the lateral supracondylar ridge
. Distal and anterior to the lateral epicondyle
. At the supinator crest of the ulna

Correct Answer & Explanation

. At the geometric center of the capitellum's axis of rotation

Explanation

The isometric point for the origin of the lateral ulnar collateral ligament (LUCL) on the humerus is located at the center of the capitellum's axis of rotation. Placing the humeral tunnel at this exact point ensures that the reconstructed ligament maintains consistent tension and provides stability across the full arc of elbow flexion and extension.

Question 862

Topic: Elbow & Forearm

A 38-year-old bodybuilder sustains a distal biceps tendon rupture and undergoes a two-incision (Mayo) repair. Postoperatively, he presents with an inability to extend his fingers and thumb, though wrist extension is preserved but deviates radially. Sensation is intact. Which technical error most likely caused this complication?

. Over-retraction of the medial antebrachial cutaneous nerve during the anterior approach
. Entrapment of the superficial radial nerve in the biceps tendon tunnel
. Vigorous retraction around the radial neck during the posterolateral exposure
. Direct transection of the anterior interosseous nerve while exposing the radial tuberosity
. Compression of the median nerve by the bicipital aponeurosis repair

Correct Answer & Explanation

. Vigorous retraction around the radial neck during the posterolateral exposure

Explanation

The patient has a posterior interosseous nerve (PIN) palsy, evidenced by the loss of finger/thumb extension and radial deviation with wrist extension (ECRL is intact via the radial nerve proper, but ECU is out). In the two-incision distal biceps repair, the PIN is at highest risk of injury during the posterolateral approach if retractors are placed too vigorously around the radial neck. Supinating the forearm moves the PIN further away from the surgical field during this step.

Question 863

Topic: Elbow & Forearm

A 45-year-old man receives a radial head replacement for a highly comminuted radial head fracture. Two years postoperatively, he complains of progressive lateral elbow pain and stiffness. Radiographs demonstrate widening of the lateral ulnohumeral joint space and erosive changes of the capitellum. What is the most likely cause of these findings?

. Overstuffing the radiocapitellar joint with a prosthetic implant that is too thick
. Undersizing the radial head implant, leading to valgus instability
. A latent subclinical infection (e.g., Cutibacterium acnes)
. Unrecognized disruption of the medial collateral ligament (MCL)
. Proximal radioulnar impingement due to an elongated implant stem

Correct Answer & Explanation

. Overstuffing the radiocapitellar joint with a prosthetic implant that is too thick

Explanation

Using a radial head implant that is too thick 'overstuffs' the radiocapitellar joint. This causes increased contact pressures on the capitellum, leading to early cartilage wear, osteonecrosis, or capitellar erosion. It also artificially widens the lateral ulnohumeral joint space on radiographs and restricts elbow flexion and forearm rotation.

Question 864

Topic: Elbow & Forearm

A 35-year-old female falls on an outstretched hand and sustains an isolated capitellar fracture.

According to the Dubberley classification of capitellum fractures, what finding distinguishes a Type 3 fracture from a Type 1 or 2, and what is its primary surgical implication?

. Involvement of the medial trochlea; requires a dual-incision approach
. Comminution of the posterior aspect of the capitellum; requires bone grafting or a posterior buttress plate
. Anterior articular cartilage impaction; requires an osteochondral autograft transfer
. Associated lateral epicondyle fracture; requires concurrent LUCL reconstruction
. Extension into the radiocapitellar joint space; mandates radial head excision

Correct Answer & Explanation

. Comminution of the posterior aspect of the capitellum; requires bone grafting or a posterior buttress plate

Explanation

The Dubberley classification for capitellum and trochlea fractures is based on the presence of posterior comminution. Type 1 involves the capitellum, Type 2 involves the capitellum and trochlea as a single piece. A Type 3 fracture is distinguished by the presence of posterior comminution, which destroys the posterior buttress. This implies that simple anterior-to-posterior screw fixation will fail due to lack of posterior support, often necessitating bone grafting or posterior buttress plating.

Question 865

Topic: Elbow & Forearm

During open reduction and internal fixation of a highly comminuted capitellum fracture, excessive posterior soft tissue stripping is performed. The patient subsequently develops avascular necrosis (AVN) of the capitellum. Which of the following best describes the anatomical basis for this complication?

. Disruption of the radial recurrent artery traversing the anterior capsule
. Disruption of the middle collateral artery traveling with the ulnar nerve
. Disruption of the end-vessels entering the capitellum via posterior capsular attachments
. Disruption of the interosseous recurrent artery at the lateral epicondyle
. Disruption of the superior ulnar collateral artery

Correct Answer & Explanation

. Disruption of the end-vessels entering the capitellum via posterior capsular attachments

Explanation

The capitellum is primarily supplied by penetrating end-vessels that enter the bone posteriorly through the capsular attachments. Because the articular surface covers the anterior, inferior, and lateral aspects of the capitellum, there is no direct anterior vascular supply. Aggressive posterior dissection or stripping of the posterior soft tissues during surgical approaches (such as an extended lateral approach) significantly increases the risk of avascular necrosis.

Question 866

Topic: Elbow & Forearm

During the surgical management of a 'Terrible Triad' injury of the elbow, the lateral ulnar collateral ligament (LUCL) is repaired to the humerus using suture anchors.

To ensure isometric function of the LUCL throughout the arc of elbow flexion and extension, where must the humeral anchor be placed?

. At the proximal pole of the lateral epicondyle
. At the exact center of rotation of the capitellum
. Anterior and superior to the capitellar axis of rotation
. Directly on the supinator crest
. Distal to the annular ligament reflection

Correct Answer & Explanation

. At the exact center of rotation of the capitellum

Explanation

The isometric point for the origin of the lateral collateral ligament complex (specifically the LUCL) is located at the center of the axis of rotation of the capitellum on the lateral epicondyle. Repairing the ligament at this exact center of rotation ensures that the ligament maintains consistent tension throughout the entire arc of elbow flexion and extension, minimizing the risk of recurrent instability or severe stiffness.

Question 867

Topic: Elbow & Forearm

A 45-year-old mechanic presents with an inability to actively extend his thumb and the fingers at the metacarpophalangeal (MCP) joints.

Wrist extension is preserved but distinctly deviates radially. Sensation in the hand and forearm is entirely normal. Which of the following structures is the most frequent site of compression causing this exact clinical picture?

. The tendinous margin of the extensor carpi radialis brevis (ECRB)
. The arcade of Struthers
. The proximal fibrous edge of the superficial head of the supinator (Arcade of Frohse)
. The distal border of the pronator teres
. The leash of Henry

Correct Answer & Explanation

. The proximal fibrous edge of the superficial head of the supinator (Arcade of Frohse)

Explanation

This is a classic presentation of Posterior Interosseous Nerve (PIN) syndrome. The PIN is a purely motor nerve after it branches from the radial nerve proper. Compression classically occurs at the Arcade of Frohse (proximal edge of the superficial head of the supinator). It leads to paralysis of the EDC, EIP, EDM, EPL, EPB, and APL. Wrist extension is preserved (but deviates radially) because the extensor carpi radialis longus (ECRL) and brevis (ECRB) are typically innervated by the radial nerve proximal to the bifurcation or arcade.

Question 868

Topic: Elbow & Forearm

A 45-year-old male weightlifter sustains an acute distal biceps tendon rupture. He undergoes operative repair via a single-incision anterior approach using cortical button fixation.

Postoperatively, he complains of an area of numbness and tingling extending down the radial (lateral) aspect of his forearm. Which nerve is most likely injured, and what specific surgical maneuver places it at highest risk?

. Posterior interosseous nerve; passing the drill pin through the dorsal cortex of the radius
. Lateral antebrachial cutaneous nerve; aggressive lateral retraction of the skin and subcutaneous tissue
. Superficial radial nerve; dissecting deep to the brachioradialis muscle belly
. Median nerve; placing retractors medially against the pronator teres
. Medial antebrachial cutaneous nerve; incision over the medial bicipital groove

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve; aggressive lateral retraction of the skin and subcutaneous tissue

Explanation

The Lateral Antebrachial Cutaneous Nerve (LABCN), which is the terminal sensory branch of the musculocutaneous nerve, exits lateral to the biceps tendon in the distal arm. It is highly susceptible to neuropraxia during a single-incision anterior approach to the distal biceps due to aggressive lateral retraction of the superficial soft tissues. It provides sensation to the radial/lateral aspect of the forearm.

Question 869

Topic: Elbow & Forearm
A 35-year-old female falls on an outstretched hand and sustains a coronal shear fracture of the distal humerus involving the capitellum and extending medially to include the lateral ridge of the trochlea. According to the Bryan and Morrey classification, what type of fracture is this?
. Type I (Hahn-Steinthal)
. Type II (Kocher-Lorenz)
. Type III (Broberg-Morrey)
. Type IV (McKee modification)
. Type V (Dubberley modification)

Correct Answer & Explanation

. Type IV (McKee modification)

Explanation

A Type IV coronal shear fracture, added by McKee to the Bryan and Morrey classification, involves the capitellum and extends medially to include the lateral ridge of the trochlea (the capitellotrochlear shear fracture). Type I involves primarily the capitellum with significant subchondral bone, whereas Type II is mostly an articular cartilage shell.

Question 870

Topic: Elbow & Forearm

A surgeon is performing a two-incision distal biceps repair (modified Boyd-Anderson approach). To minimize the risk of proximal radioulnar synostosis, which technical step is most critical during the procedure?

. Splitting the supinator muscle blindly
. Preserving the ulnar bursa
. Exposing the radial tuberosity through the extensor carpi ulnaris
. Avoiding subperiosteal dissection and exposure of the ulna
. Using a cortical button rather than suture anchors

Correct Answer & Explanation

. Avoiding subperiosteal dissection and exposure of the ulna

Explanation

In a two-incision distal biceps repair, heterotopic ossification and proximal radioulnar synostosis are major risks. This complication is minimized by strictly avoiding any exposure or subperiosteal elevation of the ulna when creating the posterolateral window.

Question 871

Topic: Elbow & Forearm

A 50-year-old female presents with a 'Terrible Triad' injury of the elbow (coronoid fracture, radial head fracture, and elbow dislocation). During surgical reconstruction, what is the generally accepted optimal sequence of repair to restore elbow stability?

. Repair the lateral ulnar collateral ligament (LUCL), fix the radial head, fix the coronoid
. Fix the radial head, repair the medial collateral ligament (MCL), fix the coronoid
. Fix or replace the radial head, fix the coronoid, repair the LUCL
. Fix the coronoid, fix or replace the radial head, repair the LUCL
. Repair the MCL, repair the LUCL, fix the coronoid

Correct Answer & Explanation

. Fix the coronoid, fix or replace the radial head, repair the LUCL

Explanation

The standard surgical algorithm for a Terrible Triad injury progresses from deep to superficial and typically from medial/anterior to lateral. The accepted sequence is: 1) Fix the coronoid (to restore the anterior buttress), 2) Fix or replace the radial head (to restore the lateral column/anterior buttress), 3) Repair the lateral collateral ligament complex (LUCL) to the lateral epicondyle. The MCL is only repaired if the elbow remains grossly unstable after these steps.

Question 872

Topic: Elbow & Forearm

A posterolateral (Kocher) approach is performed on the elbow for radial head replacement.

Which ligament is most at risk of iatrogenic injury if the origin of the extensor mass on the lateral epicondyle is aggressively elevated anteriorly?

. Annular ligament
. Radial collateral ligament
. Lateral ulnar collateral ligament (LUCL)
. Medial ulnar collateral ligament
. Quadrate ligament

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL)

Explanation

The lateral ulnar collateral ligament (LUCL) originates on the lateral epicondyle and inserts on the supinator crest of the ulna. It acts as the primary restraint to posterolateral rotatory instability (PLRI) of the elbow. If the dissection is taken too far anteriorly or distally off the lateral epicondyle, the LUCL can be severed, leading to iatrogenic PLRI.

Question 873

Topic: Elbow & Forearm
A 40-year-old female presents with an isolated coronal shear fracture of the capitellum involving a large segment of subchondral bone. How is this fracture classified according to the Bryan and Morrey system?
. Type I (Hahn-Steinthal)
. Type II (Kocher-Lorenz)
. Type III (Broberg-Morrey)
. Type IV (McKee)
. Type V (Osborne-Cotterill)

Correct Answer & Explanation

. Type I (Hahn-Steinthal)

Explanation

A Bryan and Morrey Type I fracture, also known as a Hahn-Steinthal fracture, involves a large coronal shear fracture of the capitellum that includes a significant portion of subchondral bone. Type II (Kocher-Lorenz) involves an articular cartilage sleeve with very little bone.

Question 874

Topic: Elbow & Forearm

Which tendon is most commonly involved in 'tennis elbow' (lateral epicondylitis)?

. Flexor carpi radialis
. Flexor carpi ulnaris
. Extensor carpi ulnaris
. Extensor carpi radialis brevis
. Brachioradialis

Correct Answer & Explanation

. Extensor carpi radialis brevis

Explanation

Lateral epicondylitis, or 'tennis elbow,' is a degenerative condition affecting the common extensor origin at the lateral epicondyle, with the Extensor Carpi Radialis Brevis (ECRB) tendon being most commonly involved. Repetitive wrist extension and supination contribute to its development. The other tendons listed are either flexors or less commonly involved in this specific condition.

Question 875

Topic: Elbow & Forearm

A 40-year-old female presents after falling from a height. She sustains a comminuted, unsalvageable radial head fracture, a longitudinal tear of the interosseous membrane, and dislocation of the distal radioulnar joint (DRUJ). Which of the following is the most appropriate management of the proximal radius in this specific clinical entity?

. Excision of the radial head
. Excision of the radial head with planned delayed replacement
. Immediate radial head arthroplasty
. Closed reduction and long arm casting
. Resection of the distal ulna (Darrach procedure)

Correct Answer & Explanation

. Immediate radial head arthroplasty

Explanation

This patient has an Essex-Lopresti fracture-dislocation (radial head fracture, interosseous membrane disruption, and DRUJ dislocation). Because the interosseous membrane is torn, the radiocapitellar joint becomes the primary restraint to proximal migration of the radius. Therefore, excision of the radial head is absolutely contraindicated, as it will lead to rapid proximal migration of the radius and ulnocarpal impaction. Immediate radial head arthroplasty is essential to restore longitudinal stability to the forearm.

Question 876

Topic: Elbow & Forearm

A 45-year-old male sustains a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, and coronoid fracture). The coronoid fracture is a Type II according to Regan and Morrey, and the radial head is comminuted. When proceeding with operative management, what is the classic and most biomechanically sound sequence of reconstruction?

. Radial head arthroplasty, Coronoid fixation, Lateral ulnar collateral ligament (LUCL) repair
. Coronoid fixation, Radial head arthroplasty, Lateral ulnar collateral ligament (LUCL) repair
. Lateral ulnar collateral ligament (LUCL) repair, Coronoid fixation, Radial head arthroplasty
. Radial head arthroplasty, Lateral ulnar collateral ligament (LUCL) repair, Coronoid fixation
. Coronoid fixation, Lateral ulnar collateral ligament (LUCL) repair, Radial head arthroplasty

Correct Answer & Explanation

. Coronoid fixation, Radial head arthroplasty, Lateral ulnar collateral ligament (LUCL) repair

Explanation

The classic sequence for reconstructing a terrible triad injury of the elbow proceeds from deep to superficial and medial to lateral: 1) Fixation of the coronoid process, 2) Repair or replacement of the radial head, and 3) Repair of the lateral collateral ligament complex (LUCL). The medial collateral ligament is only repaired if the elbow remains unstable after the primary triad of structures is restored.

Question 877

Topic: Elbow & Forearm

A 6-year-old boy presents with a Bado Type I Monteggia fracture-dislocation (anterior dislocation of the radial head with fracture of the ulnar diaphysis). In the operating room, an anatomic closed reduction of the ulnar shaft is achieved and confirmed under fluoroscopy; however, the radial head remains persistently dislocated. What is the most likely cause of this persistent radial head dislocation?

. Ulnar malreduction
. Annular ligament interposition
. Biceps tendon interposition
. Radial nerve entrapment
. Plastic deformation of the radius

Correct Answer & Explanation

. Annular ligament interposition

Explanation

The most common overall cause of persistent radial head dislocation in a Monteggia injury is failure to achieve an anatomic reduction of the ulna (ulnar malreduction or length discrepancy). However, the question specifies that anatomic reduction of the ulna was achieved. When the ulna is perfectly out-to-length and the radial head still will not reduce, the most common blocking structure is interposition of the torn annular ligament or joint capsule.

Question 878

Topic: Elbow & Forearm

Surgical management of a 'Terrible Triad' injury of the elbow (elbow dislocation, radial head fracture, coronoid fracture) typically follows a systematic approach to restore joint stability. What is the standard, most widely accepted sequence of structural repair/fixation during the operation?

. LCL complex repair, followed by radial head, then coronoid
. Coronoid (or anterior capsule), followed by radial head, then LCL complex
. Radial head fixation, followed by coronoid, then MCL repair
. MCL repair, followed by coronoid, then radial head
. LCL complex repair, followed by MCL repair, then radial head

Correct Answer & Explanation

. Coronoid (or anterior capsule), followed by radial head, then LCL complex

Explanation

The standard surgical algorithm for a terrible triad injury utilizes a deep-to-superficial (inside-out) approach. Fixation begins with the deepest anterior structure, the coronoid (or anterior capsule repair if the fragment is too small). Next, the radial head is either fixed (ORIF) or replaced, restoring the anterior/lateral bony column. Finally, the lateral collateral ligament (LCL) complex is repaired to the lateral epicondyle. MCL repair or cross-pinning/hinged ex-fix is reserved for residual instability after the primary lateral-sided and bony repairs.

Question 879

Topic: Elbow & Forearm

A 45-year-old female falls on an outstretched hand and sustains a capitellum fracture. CT imaging demonstrates a coronal shear fracture that involves the capitellum and the lateral ridge of the trochlea, with extensive posterior articular comminution. Based on the Dubberley classification, this is a Type 3B fracture. What does the 'B' designation specifically indicate in this classification?

. Involvement of the medial trochlea
. An associated radial head fracture
. Posterior radiocapitellar comminution
. An associated avulsion of the lateral ulnar collateral ligament
. Intact posterior articular cartilage

Correct Answer & Explanation

. Posterior radiocapitellar comminution

Explanation

The Dubberley classification of capitellar/trochlear shear fractures categorizes based on anatomical involvement: Type 1 (capitellum only), Type 2 (capitellum + lateral trochlear ridge), Type 3 (capitellum + entire trochlea). The modifiers 'A' and 'B' refer to the absence or presence of posterior radiocapitellar comminution, respectively. A Type 'B' fracture is critical because posterior comminution means there is no posterior buttress, making isolated anterior-to-posterior screw fixation prone to failure; these often require a posterior surgical approach and structural grafting or arthroplasty.

Question 880

Topic: Elbow & Forearm

A 35-year-old male sustains a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, coronoid fracture). Standard surgical management requires a specific sequence of repair. Which of the following is the most widely accepted first step in the internal fixation sequence for this injury?

. Repair of the lateral collateral ligament (LCL) complex
. Fixation or replacement of the radial head
. Fixation of the coronoid process fracture
. Repair of the medial collateral ligament (MCL)
. Application of a hinged external fixator

Correct Answer & Explanation

. Fixation of the coronoid process fracture

Explanation

The standard surgical sequence for a terrible triad injury proceeds deep to superficial and distal to proximal: fixation of the coronoid fracture first, followed by fixation or arthroplasty of the radial head, and finally repair of the lateral ulnar collateral ligament (LUCL/LCL complex). MCL repair is generally only performed if the elbow remains unstable after the lateral side is fixed.

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