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Elbow & Forearm MCQs

Practice Set 35 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 681

Topic: Elbow & Forearm

A 42-year-old male weightlifter feels a pop in his anterior elbow while performing a heavy deadlift. Clinical examination reveals a positive Hook test. If surgical repair of the ruptured distal biceps tendon is performed via a single anterior incision technique, which of the following nerves is at the highest risk of iatrogenic injury?

. Lateral antebrachial cutaneous nerve
. Posterior interosseous nerve
. Ulnar nerve
. Median nerve
. Anterior interosseous nerve

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve

Explanation

The lateral antebrachial cutaneous nerve (LABCN) is the most commonly injured nerve during a single-incision anterior approach for distal biceps tendon repair, with reported injury or neuropraxia rates ranging from 10% to 30%. The LABCN exits the deep fascia just lateral to the biceps tendon in the antecubital fossa. While the posterior interosseous nerve (PIN) is also at risk (particularly with errant placement of retractors around the radial neck), LABCN injury is much more frequent. A two-incision approach classically reduced the risk of PIN injury but historically carried a higher risk of radioulnar synostosis.

Question 682

Topic: Elbow & Forearm

A 35-year-old man falls from a height and sustains a traumatic elbow dislocation. After closed reduction, radiographs reveal a displaced radial head fracture, a small type 1 coronoid tip fracture, and a lateral collateral ligament (LCL) tear. He is scheduled for operative fixation. What is the standard and most appropriate sequence of surgical repair for this 'terrible triad' injury?

. Coronoid fixation, radial head fixation/replacement, LCL repair, followed by MCL repair if still unstable
. Radial head fixation, coronoid fixation, LCL repair, followed by MCL repair if still unstable
. LCL repair, radial head fixation, coronoid fixation, MCL repair
. MCL repair, radial head fixation, coronoid fixation, LCL repair
. Coronoid fixation, LCL repair, radial head fixation/replacement, MCL repair

Correct Answer & Explanation

. Coronoid fixation, radial head fixation/replacement, LCL repair, followed by MCL repair if still unstable

Explanation

The standard surgical protocol for a terrible triad injury of the elbow proceeds from deep to superficial. The typical sequence is: 1) Coronoid fixation or anterior capsule repair, 2) Radial head fixation or replacement, 3) Lateral collateral ligament (LCL) repair. If the elbow remains unstable after these steps, the medial collateral ligament (MCL) may be repaired or a hinged external fixator applied.

Question 683

Topic: Elbow & Forearm

A 38-year-old woman falls on an outstretched hand and sustains a 'terrible triad' injury to her right elbow. Which of the following represents the most appropriate sequence of surgical reconstruction to effectively restore joint stability?

. Lateral ulnar collateral ligament (LUCL) repair, radial head fixation/replacement, coronoid fixation
. Coronoid fixation, LUCL repair, radial head fixation/replacement
. Coronoid fixation, radial head fixation/replacement, LUCL repair
. Radial head fixation/replacement, LUCL repair, coronoid fixation
. LUCL repair, coronoid fixation, radial head fixation/replacement

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL) repair, radial head fixation/replacement, coronoid fixation

Explanation

The standard surgical protocol for a terrible triad injury of the elbow (elbow dislocation, radial head fracture, coronoid fracture) typically proceeds from deep to superficial and medial to lateral (if approached from a single lateral incision). The widely accepted sequence is: 1) fixation of the coronoid process to restore the anterior buttress, 2) repair or replacement of the radial head to restore the anterior and valgus buttress, and 3) repair of the lateral ulnar collateral ligament (LUCL) to restore posterolateral rotatory stability. If the elbow remains unstable after these steps, the medial collateral ligament (MCL) may be repaired or a hinged external fixator applied.

Question 684

Topic: Elbow & Forearm

A 6-year-old boy sustains a Bado Type I Monteggia fracture-dislocation. Radiographs show a plastic deformation of the ulna and an anterior dislocation of the radial head. During closed reduction, the radial head reduces when the forearm is supinated and the elbow is flexed, but it repeatedly subluxates upon pronation. What is the most critical step to ensure stable maintenance of the radial head reduction?

. Annular ligament reconstruction
. Transarticular radiocapitellar pinning
. Operative correction of the ulnar deformity
. Cast immobilization in full extension and pronation
. Resection of the radial head

Correct Answer & Explanation

. Annular ligament reconstruction

Explanation

In pediatric Monteggia fractures, the stability of the radial head is entirely dependent on the length and anatomic alignment of the ulna. If the radial head subluxates or fails to remain reduced, it is almost always due to incomplete correction of the ulnar deformity (including plastic deformation). Operative correction of the ulna is required to restore length and alignment, which will spontaneously stabilize the radial head.

Question 685

Topic: Elbow & Forearm

A 40-year-old man sustains a terrible triad injury to his left elbow following a fall from a height. Intraoperatively, through a lateral approach, the radial head is replaced and the coronoid fracture is anatomically fixed. However, during range of motion testing, the elbow tends to subluxate posteriorly when brought into extension. Which of the following structures must be addressed next to restore stability?

. Anterior bundle of the medial collateral ligament (MCL)
. Posterior bundle of the medial collateral ligament (MCL)
. Lateral ulnar collateral ligament (LUCL)
. Annular ligament
. Brachialis tendon insertion

Correct Answer & Explanation

. Anterior bundle of the medial collateral ligament (MCL)

Explanation

The standard surgical algorithm for terrible triad injuries of the elbow involves stabilizing the coronoid, restoring the radial head, and repairing the lateral ligamentous complex, specifically the lateral ulnar collateral ligament (LUCL). The LUCL is the primary lateral stabilizer against posterolateral rotatory instability. If the elbow remains unstable after coronoid, radial head, and LUCL repair, then repair of the medial collateral ligament (MCL) or application of a hinged external fixator should be considered.

Question 686

Topic: Elbow & Forearm

A 45-year-old man undergoes repair of an acute distal biceps tendon rupture via a single-incision anterior approach.

Postoperatively, he notes a patch of numbness on the radial aspect of his forearm. Which nerve was most likely injured or stretched during the surgical exposure?

. Lateral antebrachial cutaneous nerve (LABCN)
. Posterior interosseous nerve (PIN)
. Superficial radial nerve
. Anterior interosseous nerve (AIN)
. Medial antebrachial cutaneous nerve (MABCN)

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve (LABCN)

Explanation

The lateral antebrachial cutaneous nerve (LABCN) is the most commonly injured nerve during a single-incision anterior approach for distal biceps repair. It runs in the subcutaneous tissue near the cephalic vein in the lateral aspect of the antecubital fossa and is highly vulnerable during superficial dissection and retraction. While the PIN is at risk during deep retractor placement radially or in a two-incision approach, the LABCN is overall the most frequently affected.

Question 687

Topic: Elbow & Forearm

A 38-year-old male weightlifter undergoes surgical repair of a complete distal biceps tendon rupture via a single-incision anterior approach. Postoperatively, he complains of numbness and tingling over the anterolateral aspect of his forearm. Motor function of the hand and wrist is completely intact. Which nerve is most likely injured, and what is its anatomic relationship to the biceps tendon?

. Posterior interosseous nerve; it crosses anterior to the radial neck
. Lateral antebrachial cutaneous nerve; it emerges lateral to the biceps tendon between the biceps and brachialis
. Superficial radial nerve; it runs deep to the brachioradialis
. Medial antebrachial cutaneous nerve; it runs medial to the brachial artery
. Anterior interosseous nerve; it branches from the median nerve in the proximal forearm

Correct Answer & Explanation

. Posterior interosseous nerve; it crosses anterior to the radial neck

Explanation

The lateral antebrachial cutaneous nerve (LABCN), which is the terminal sensory branch of the musculocutaneous nerve, is the most commonly injured nerve during a single-incision anterior approach for distal biceps repair. It emerges from beneath the lateral edge of the biceps muscle, passing between the biceps and brachialis, making it highly vulnerable during retraction. The posterior interosseous nerve (PIN) is more commonly injured during a two-incision approach or if retractors are placed blindly around the radial neck.

Question 688

Topic: Elbow & Forearm

A 35-year-old man falls from a height and sustains a 'terrible triad' injury of the elbow. During surgical reconstruction, the surgeon successfully fixes the coronoid fracture and replaces the highly comminuted radial head. However, the elbow remains persistently unstable in extension and supination. Which of the following is the most critical next step to restore stability?

. Application of a hinged external fixator
. Anterior capsule reconstruction
. Repair of the lateral ulnar collateral ligament (LUCL) to the lateral epicondyle
. Repair of the medial ulnar collateral ligament (MUCL)
. Fascia lata allograft reconstruction of the annular ligament

Correct Answer & Explanation

. Application of a hinged external fixator

Explanation

The terrible triad of the elbow consists of an elbow dislocation, a radial head fracture, and a coronoid fracture. The standard surgical sequence involves addressing the coronoid, fixing or replacing the radial head, and repairing the lateral collateral ligament (LCL) complex—specifically the lateral ulnar collateral ligament (LUCL)—to its isometric origin on the lateral epicondyle. The LUCL is the primary restraint to posterolateral rotatory instability and is virtually always torn in this injury mechanism. Repairing the MUCL or applying an external fixator is generally reserved for residual instability after the LUCL has been properly repaired.

Question 689

Topic: Elbow & Forearm

A 42-year-old bodybuilder undergoes a single-incision anterior approach for the repair of a complete acute distal biceps tendon rupture. In the recovery room, he complains of numbness and tingling along the lateral (radial) border of his forearm. Motor function is fully intact. Which nerve was most likely injured or compressed by retractors during the surgical exposure?

. Posterior interosseous nerve (PIN)
. Superficial branch of the radial nerve
. Medial antebrachial cutaneous nerve
. Anterior interosseous nerve (AIN)
. Lateral antebrachial cutaneous nerve (LABCN)

Correct Answer & Explanation

. Posterior interosseous nerve (PIN)

Explanation

The lateral antebrachial cutaneous nerve (LABCN) is the terminal sensory branch of the musculocutaneous nerve. It exits the deep fascia lateral to the biceps tendon and is the most commonly injured nerve during a single-incision anterior approach for distal biceps repair due to retraction or direct trauma. Injury results in paresthesias or numbness along the lateral aspect of the forearm. While the posterior interosseous nerve (PIN) is the most dreaded motor nerve injury (causing weak finger/thumb extension), the patient's intact motor function and specific sensory distribution point to the LABCN.

Question 690

Topic: Elbow & Forearm

A 45-year-old man sustains a fall on an outstretched hand, resulting in a 'terrible triad' injury of the elbow. Intraoperatively, the coronoid is found to have a small tip fracture, which is treated with anterior capsular repair. A radial head arthroplasty is performed for a comminuted radial head fracture. Following these steps, the elbow remains persistently unstable in extension and supinates when extended. Which of the following is the most appropriate next step in management?

. Repair of the medial ulnar collateral ligament (MUCL)
. Application of a hinged external fixator
. Repair of the lateral ulnar collateral ligament (LUCL)
. Open reduction and internal fixation of the coronoid process
. Transarticular pinning of the ulnohumeral joint

Correct Answer & Explanation

. Repair of the medial ulnar collateral ligament (MUCL)

Explanation

The standard surgical algorithm for a terrible triad injury involves restoring the anterior column (coronoid), the lateral column (radial head), and the lateral stabilizing structures (LCL complex, specifically the LUCL). If the elbow remains unstable after addressing the coronoid and radial head, the LUCL must be repaired. MUCL repair or hinged external fixation is generally reserved for cases where the elbow remains unstable despite a secure LUCL repair.

Question 691

Topic: Elbow & Forearm

A 45-year-old man sustains a fall from a height and presents with a 'terrible triad' injury of the elbow. Which of the following correctly describes the typical deep surgical sequence for operative repair of this injury?

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

Correct Answer & Explanation

. Lateral collateral ligament repair, coronoid fixation, radial head fixation/replacement

Explanation

The terrible triad of the elbow consists of an elbow dislocation, a radial head fracture, and a coronoid fracture. The standard 'inside-out' protocol for surgical management involves: 1) repairing or fixing the coronoid fracture to restore the anterior buttress, 2) fixing or replacing the radial head to restore the anterior and valgus buttress, and 3) repairing the lateral ulnar collateral ligament (LUCL) to restore posterolateral rotatory stability. The medial collateral ligament is only addressed if profound instability persists after the standard sequence.

Question 692

Topic: Elbow & Forearm

A 35-year-old bodybuilder undergoes a two-incision (modified Boyd-Anderson) repair of a distal biceps tendon rupture. Compared to a single anterior incision approach, he is at an increased risk for which of the following complications?

. Lateral antebrachial cutaneous nerve palsy
. Radial nerve palsy
. Heterotopic ossification
. Posterior interosseous nerve palsy
. Median nerve palsy

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve palsy

Explanation

The two-incision technique for distal biceps tendon repair was developed to decrease the risk of posterior interosseous nerve (PIN) injury, which was a historic concern with the single anterior incision approach. However, the two-incision approach carries a significantly higher risk of heterotopic ossification (specifically radioulnar synostosis), especially if the interosseous membrane is heavily breached or muscle bellies are traumatized. The single anterior incision is most commonly associated with lateral antebrachial cutaneous (LABC) nerve neurapraxia.

Question 693

Topic: Elbow & Forearm

A 38-year-old construction worker falls from a ladder and sustains a 'terrible triad' injury of the elbow. He is taken to the operating room for surgical stabilization. To optimize stability and functional outcomes, what is the most widely accepted sequence for repairing the injured structures?

. Lateral collateral ligament (LCL) repair, radial head fixation/replacement, coronoid repair
. Coronoid repair, radial head fixation/replacement, lateral collateral ligament (LCL) repair
. Radial head fixation/replacement, lateral collateral ligament (LCL) repair, coronoid repair
. Medial collateral ligament (MCL) repair, coronoid repair, radial head fixation/replacement
. Coronoid repair, medial collateral ligament (MCL) repair, radial head fixation/replacement

Correct Answer & Explanation

. Lateral collateral ligament (LCL) repair, radial head fixation/replacement, coronoid repair

Explanation

The terrible triad of the elbow consists of an elbow dislocation, a radial head fracture, and a coronoid fracture. The standard surgical protocol dictates a 'deep to superficial' approach. The sequence begins with restoring the anterior column by fixing the coronoid fracture or anterior capsule, followed by restoring the lateral column by fixing or replacing the radial head, and finally repairing the lateral collateral ligament (LCL) complex to the lateral epicondyle.

Question 694

Topic: Elbow & Forearm

A 45-year-old weightlifter feels a sudden 'pop' in his anterior elbow during a heavy biceps curl. Examination demonstrates a positive hook test. He undergoes a single-incision distal biceps tendon repair. Which of the following is the most commonly reported complication specifically associated with this surgical approach?

. Posterior interosseous nerve (PIN) neuropraxia
. Heterotopic ossification
. Radioulnar synostosis
. Lateral antebrachial cutaneous nerve (LABCN) neuropraxia
. Medial antebrachial cutaneous nerve neuropraxia

Correct Answer & Explanation

. Posterior interosseous nerve (PIN) neuropraxia

Explanation

The single-incision anterior approach for distal biceps tendon repair is most commonly associated with neuropraxia of the lateral antebrachial cutaneous nerve (LABCN) due to its proximity to the superficial surgical dissection. The two-incision approach has a historically higher risk of radioulnar synostosis and heterotopic ossification. While PIN injury can occur with both approaches, it is less frequent than LABCN injury in the single-incision technique.

Question 695

Topic: Elbow & Forearm

A 34-year-old man falls on an outstretched hand and sustains a coronal shear fracture of the capitellum that extends medially to include the majority of the trochlea (McKee modification Type IV). Which surgical approach and fixation strategy is considered most appropriate for direct visualization and anatomic reconstruction of this specific fracture pattern?

. Posterior approach with olecranon osteotomy and posterior-to-anterior headless screws
. Extensile lateral approach with anterior-to-posterior headless compression screws
. Medial approach with bridging plate fixation
. Anterior approach with mini-fragment plate fixation
. Arthroscopic debridement and fragment excision

Correct Answer & Explanation

. Posterior approach with olecranon osteotomy and posterior-to-anterior headless screws

Explanation

Capitellar and trochlear shear fractures (Bryan and Morrey types, including the McKee modification Type IV) are articular fractures requiring anatomic reduction and rigid fixation. An extensile lateral approach (e.g., extended Kocher or Kaplan) provides excellent visualization of the capitellum and lateral trochlea. Fixation is classically achieved using headless compression screws placed from anterior to posterior, burying the heads beneath the articular cartilage to allow early range of motion without impinging on the radial head.

Question 696

Topic: Elbow & Forearm

A 42-year-old man falls on an outstretched hand and sustains a posterior elbow dislocation, a radial head fracture, and a coronoid process fracture. During the surgical reconstruction of this "terrible triad" injury, what is the generally recommended sequence of repair to restore elbow stability?

. Coronoid fixation, radial head repair/replacement, lateral collateral ligament (LCL) repair
. Lateral collateral ligament (LCL) repair, radial head repair/replacement, coronoid fixation
. Radial head repair/replacement, coronoid fixation, lateral collateral ligament (LCL) repair
. Coronoid fixation, lateral collateral ligament (LCL) repair, radial head repair/replacement
. Lateral collateral ligament (LCL) repair, coronoid fixation, radial head repair/replacement

Correct Answer & Explanation

. Coronoid fixation, radial head repair/replacement, lateral collateral ligament (LCL) repair

Explanation

The standard surgical sequence for treating a terrible triad injury of the elbow typically proceeds from deep to superficial, or "inside-out." The recommended sequence is fixation of the coronoid (to restore the anterior buttress), followed by repair or replacement of the radial head (to address anterior and lateral stability), and finally repair of the lateral ulnar collateral ligament (LUCL) complex. If the elbow remains unstable after these steps, the medial collateral ligament (MCL) may be repaired or a hinged external fixator applied.

Question 697

Topic: Elbow & Forearm

Following a radial head fracture, a surgeon must assess the blood supply to the radial head. The primary blood supply to the radial head is derived from which artery?

. Brachial artery
. Ulnar artery
. Posterior interosseous artery
. Radial recurrent artery (from radial artery)
. Anterior interosseous artery

Correct Answer & Explanation

. Brachial artery

Explanation

The radial head primarily receives its blood supply from the radial recurrent artery, which is a branch of the radial artery. This artery forms an anastomosis around the elbow joint. While other arteries contribute to the overall elbow circulation, the radial recurrent artery is specifically responsible for the majority of the blood supply to the radial head. This is clinically relevant in complex radial head fractures where comminution or displacement can compromise this delicate blood supply, leading to avascular necrosis.

Question 698

Topic: Elbow & Forearm

Posterolateral rotatory instability (PLRI) of the elbow typically results from an insufficiency of the lateral ulnar collateral ligament (LUCL). To effectively reconstruct this ligament, the surgeon must anatomically recreate its attachments. What are the correct anatomical origin and insertion of the LUCL?

. Origin: Medial epicondyle; Insertion: Sublime tubercle of the ulna
. Origin: Lateral epicondyle; Insertion: Annular ligament
. Origin: Lateral epicondyle; Insertion: Supinator crest of the ulna
. Origin: Radial head; Insertion: Radial notch of the ulna
. Origin: Lateral epicondyle; Insertion: Radial tuberosity

Correct Answer & Explanation

. Origin: Medial epicondyle; Insertion: Sublime tubercle of the ulna

Explanation

The lateral collateral ligament complex of the elbow consists of the radial collateral ligament, the lateral ulnar collateral ligament (LUCL), and the annular ligament. The LUCL is the primary restraint to posterolateral rotatory instability (PLRI). It originates from the lateral epicondyle of the humerus and inserts onto the supinator crest of the proximal ulna. For context, the sublime tubercle is the insertion site for the anterior band of the medial ulnar collateral ligament.

Question 699

Topic: Elbow & Forearm

A 32-year-old female presents with recurrent posterolateral rotatory instability (PLRI) of her right elbow following a traumatic dislocation 6 months ago. Reconstruction of the lateral ulnar collateral ligament (LUCL) is planned. What are the correct anatomical origin and insertion sites for the LUCL?

. Lateral epicondyle to the radial head
. Capitellum to the annular ligament
. Medial epicondyle to the sublime tubercle
. Lateral epicondyle to the supinator crest of the proximal ulna
. Coronoid process to the radial tuberosity

Correct Answer & Explanation

. Lateral epicondyle to the radial head

Explanation

The lateral ulnar collateral ligament (LUCL) is the primary restraint to posterolateral rotatory instability (PLRI) of the elbow. It originates on the lateral epicondyle (blending with the lateral collateral ligament complex) and courses distally and posteriorly to insert on the supinator crest of the proximal ulna. The anterior band of the medial collateral ligament (MCL) originates on the medial epicondyle and inserts on the sublime tubercle of the coronoid.

Question 700

Topic: Elbow & Forearm

A 32-year-old male sustains a Monteggia fracture-dislocation. He undergoes open reduction and internal fixation of the ulna with closed reduction of the radial head. Postoperatively, he is unable to actively extend his thumb and fingers at the metacarpophalangeal joints. Wrist extension is preserved but occurs with radial deviation. Compression or injury to the affected nerve most commonly occurs at which of the following anatomic structures?

. Ligament of Struthers
. Lacertus fibrosus
. Arcade of Frohse
. Osborne's ligament
. Between the two heads of the pronator teres

Correct Answer & Explanation

. Ligament of Struthers

Explanation

The patient is exhibiting symptoms of a posterior interosseous nerve (PIN) palsy. The PIN innervates the finger and thumb extensors and the extensor carpi ulnaris (ECU). Because the extensor carpi radialis longus (ECRL) and brevis (ECRB) are often innervated by the radial nerve proximal to the PIN branch, wrist extension is preserved but deviates radially. The most common site of PIN compression is the Arcade of Frohse, which is the thickened proximal tendinous edge of the superficial head of the supinator muscle.

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