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Elbow & Forearm MCQs

Practice Set 47 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 921

Topic: Elbow & Forearm

A 45-year-old male sustains a 'terrible triad' injury of the elbow after a fall on an outstretched hand. Which of the following represents the most widely accepted sequence of surgical reconstruction to restore elbow stability?

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

Correct Answer & Explanation

. LCL repair, coronoid fixation, radial head replacement

Explanation

The standard surgical protocol for a terrible triad of the elbow (elbow dislocation, radial head fracture, coronoid fracture) typically proceeds from deep to superficial: 1) Coronoid fixation or anterior capsule repair, 2) Radial head fixation or arthroplasty, and 3) Lateral ulnar collateral ligament (LUCL) repair. If the elbow remains unstable after these steps, the MCL may be repaired or an external fixator applied.

Question 922

Topic: Elbow & Forearm

A 32-year-old female sustains an Essex-Lopresti injury. She undergoes radial head excision without prosthetic replacement. Which of the following is the most likely late complication?

. Distal radioulnar joint (DRUJ) ankylosis
. Ulnar nerve palsy
. Proximal migration of the radius and ulnar impaction syndrome
. Avascular necrosis of the capitellum
. Cubitus varus deformity

Correct Answer & Explanation

. Distal radioulnar joint (DRUJ) ankylosis

Explanation

An Essex-Lopresti injury consists of a radial head fracture, tear of the interosseous membrane, and disruption of the DRUJ. If the radial head is excised without being replaced, the radius will migrate proximally due to the loss of the stabilizing interosseous membrane and radial head. This leads to positive ulnar variance and severe ulnar impaction syndrome.

Question 923

Topic: Elbow & Forearm

A 42-year-old female sustains a terrible triad injury of the elbow (elbow dislocation, radial head fracture, and coronoid fracture). During surgical reconstruction, what is the most appropriate standard sequence of repair?

. Coronoid fixation, LCL repair, radial head fixation, MCL repair
. Radial head fixation, coronoid fixation, LCL repair, MCL repair
. Coronoid fixation, radial head fixation, LCL repair, common extensor origin repair
. LCL repair, radial head fixation, coronoid fixation, common extensor repair
. Coronoid fixation, LCL repair, radial head excision, MCL repair

Correct Answer & Explanation

. Coronoid fixation, LCL repair, radial head fixation, MCL repair

Explanation

The standard sequence for reconstructing a terrible triad injury is working deep to superficial: coronoid fixation, radial head fixation or replacement, followed by lateral collateral ligament (LCL) and extensor origin repair.

Question 924

Topic: Elbow & Forearm

A 40-year-old male is undergoing a two-incision approach for a distal biceps tendon repair. Compared to a single anterior incision approach, which of the following complications occurs at a higher rate with the two-incision technique?

. Heterotopic ossification (radioulnar synostosis)
. Lateral antebrachial cutaneous nerve palsy
. Radial nerve palsy
. Tendon re-rupture
. Median nerve injury

Correct Answer & Explanation

. Heterotopic ossification (radioulnar synostosis)

Explanation

The two-incision approach (modified Boyd-Anderson) carries a higher risk of heterotopic ossification and radioulnar synostosis due to muscle dissection, whereas the single anterior incision has a higher risk of lateral antebrachial cutaneous nerve neuropraxia.

Question 925

Topic: Elbow & Forearm

A 35-year-old female fell on her outstretched hand.

Radiographs show a radial head fracture with 3 mm of articular step-off. On examination, there is a distinct mechanical block to forearm pronation and supination. What is the most appropriate treatment?

. Open reduction and internal fixation (ORIF) of the radial head
. A sling for 3 days followed by early active motion
. Long-arm cast immobilization for 4 weeks
. Complete radial head resection
. Radial head arthroplasty

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF) of the radial head

Explanation

A displaced radial head fracture (Mason Type II) that causes a mechanical block to forearm rotation is an indication for surgical intervention, typically ORIF if the fragment is large enough and amenable to fixation.

Question 926

Topic: Elbow & Forearm

A 32-year-old gymnast falls from a height and sustains a 'terrible triad' injury of the elbow. Operative intervention is planned. To properly restore elbow stability in a step-wise fashion, what is the accepted standard sequence of surgical repair?

. Lateral collateral ligament (LCL) -> Radial head -> Coronoid
. Radial head -> Coronoid -> Medial collateral ligament (MCL)
. Medial collateral ligament (MCL) -> Radial head -> Coronoid
. Coronoid -> Lateral collateral ligament (LCL) -> Radial head
. Coronoid -> Radial head -> Lateral collateral ligament (LCL)

Correct Answer & Explanation

. Lateral collateral ligament (LCL) -> Radial head -> Coronoid

Explanation

The standard surgical algorithm for a terrible triad injury follows an 'inside-out' approach. The deep anterior structures (coronoid) are repaired first, followed by the radial head, and finally the lateral collateral ligament (LCL) complex.

Question 927

Topic: Elbow & Forearm

A 45-year-old female sustains a 'terrible triad' injury to the elbow. During surgical reconstruction, after fixing the coronoid and radial head, the elbow remains persistently unstable in extension. What is the next most appropriate step?

. Repair the medial collateral ligament (MCL)
. Apply a hinged external fixator
. Repair the lateral ulnar collateral ligament (LUCL) origin to the lateral epicondyle
. Resect the radial head
. Immobilize in 90 degrees of flexion for 6 weeks

Correct Answer & Explanation

. Repair the medial collateral ligament (MCL)

Explanation

The standard surgical algorithm for a terrible triad injury involves fixation of the coronoid and radial head, followed by repair of the lateral ulnar collateral ligament (LUCL). This restores posterolateral rotatory stability.

Question 928

Topic: Elbow & Forearm

A 'terrible triad' injury of the elbow involves an elbow dislocation, a radial head fracture, and a coronoid process fracture. When undertaking surgical repair, which of the following represents the standard, sequential order of fixation to progressively restore elbow stability?

. Coronoid fixation, followed by Radial head fixation/replacement, followed by Lateral collateral ligament (LCL) repair
. Radial head fixation/replacement, followed by Coronoid fixation, followed by LCL repair
. LCL repair, followed by Coronoid fixation, followed by Radial head fixation
. Coronoid fixation, followed by Medial collateral ligament (MCL) repair, followed by Radial head fixation
. LCL repair, followed by Radial head fixation, followed by Medial collateral ligament repair

Correct Answer & Explanation

. Coronoid fixation, followed by Radial head fixation/replacement, followed by Lateral collateral ligament (LCL) repair

Explanation

The standard surgical protocol for a terrible triad injury involves a systematic approach working deep to superficial and typically from medial (via deep exposure through lateral side) to lateral. The order is: 1) Coronoid fixation or capsular repair, 2) Radial head fixation or arthroplasty, and 3) Lateral collateral ligament (LUCL) complex repair to the lateral epicondyle.

Question 929

Topic: Elbow & Forearm

A 35-year-old bodybuilder undergoes a two-incision technique for repair of a distal biceps tendon rupture. Six months postoperatively, he presents with severely restricted forearm pronation and supination, though elbow flexion and extension are normal. What is the most likely complication he developed from this specific surgical approach?

. Posterior interosseous nerve (PIN) entrapment
. Proximal radioulnar synostosis
. Medial collateral ligament insufficiency
. Recurrent distal biceps rupture
. Capitellar osteochondritis dissecans

Correct Answer & Explanation

. Posterior interosseous nerve (PIN) entrapment

Explanation

The two-incision technique (modified Boyd-Anderson) for distal biceps repair was developed to reduce the risk of posterior interosseous nerve (PIN) injury associated with the extensile single anterior incision. However, muscle splitting and subperiosteal dissection between the radius and ulna during the posterior approach increases the risk of heterotopic ossification, specifically proximal radioulnar synostosis. This complication leads to profound loss of forearm rotation (pronation/supination). Careful technique to avoid exposing the ulna or breaching the interosseous membrane is critical.

Question 930

Topic: Elbow & Forearm

A 32-year-old female falls onto her outstretched hand and sustains a fracture of the anteromedial facet of the coronoid process of the ulna. Based on this specific fracture pattern, what is the underlying mechanism of injury and the associated ligamentous pathology?

. Valgus extension overload; rupture of the anterior bundle of the MCL.
. Posterolateral rotatory instability; rupture of the LUCL and anterior capsule.
. Varus posteromedial rotatory instability; rupture of the LCL complex and preservation of the anterior bundle of the MCL.
. Direct axial loading in hyperflexion; rupture of both MCL and LCL complexes.
. Olecranon shear force; isolated rupture of the posterior band of the MCL.

Correct Answer & Explanation

. Valgus extension overload; rupture of the anterior bundle of the MCL.

Explanation

Anteromedial facet fractures of the coronoid are the hallmark of Varus Posteromedial Rotatory Instability (VPMRI). This injury pattern is caused by a varus stress applied to the elbow, combined with axial load and posteromedial rotation of the ulna. This forces the anteromedial coronoid facet to impact the trochlea, causing a fracture. The lateral collateral ligament (LCL) complex is classically avulsed or torn, leading to the varus instability. The anterior bundle of the medial collateral ligament (MCL) usually remains intact or is only partially injured.

Question 931

Topic: Elbow & Forearm
According to the McKee modification of the Bryan and Morrey classification for capitellum fractures, what describes a Type IV injury?
. An isolated osteochondral shear fracture of the capitellum (Hahn-Steinthal).
. A fracture involving the capitellum and a thin sleeve of cartilage (Kocher-Lorenz).
. A highly comminuted fracture of the capitellum (Broberg-Morrey).
. A coronal shear fracture that includes the capitellum and the majority of the trochlea.
. A fracture of the capitellum extending proximally into the lateral epicondyle.

Correct Answer & Explanation

. A coronal shear fracture that includes the capitellum and the majority of the trochlea.

Explanation

The Bryan and Morrey classification divides capitellar fractures into three primary types: Type I (Hahn-Steinthal, large osseous fragment), Type II (Kocher-Lorenz, primarily articular cartilage with a thin layer of bone), and Type III (Broberg-Morrey, comminuted). McKee later modified this classification by adding Type IV, which is a coronal shear fracture that involves not only the capitellum but extends medially to include the majority of the trochlea. Identifying a Type IV fracture is critical, as it requires fixation of both the capitellum and the trochlear fragment to restore elbow biomechanics.

Question 932

Topic: Elbow & Forearm

A 45-year-old female presents with severe lateral elbow pain exacerbated by lifting objects with the forearm pronated. She is diagnosed with lateral epicondylitis. Histopathologic examination of the affected tissue typically reveals angiofibroblastic hyperplasia rather than acute inflammation. Which tendon is considered the primary site of pathology in this condition?

. Extensor digitorum communis
. Extensor carpi radialis longus
. Extensor carpi radialis brevis
. Extensor carpi ulnaris
. Brachioradialis

Correct Answer & Explanation

. Extensor digitorum communis

Explanation

Lateral epicondylitis (tennis elbow) is a tendinopathy (angiofibroblastic tendinosis) primarily involving the origin of the extensor carpi radialis brevis (ECRB) tendon. The ECRB lies deep to the extensor carpi radialis longus (ECRL) and extensor digitorum communis (EDC). The chronic microtrauma at its origin on the lateral epicondyle leads to tissue degeneration rather than active inflammatory cells. The ECRL and EDC can be secondarily involved, but the ECRB is the hallmark site of pathology.

Question 933

Topic: Elbow & Forearm
A 50-year-old female undergoes a radial head arthroplasty for a comminuted, irreparable radial head fracture (Mason Type III). During the procedure, the surgeon inadvertently implants a prosthesis that is 4 mm too thick. What is the most likely clinical and radiographic consequence of this technical error?
. Valgus instability with attenuation of the medial collateral ligament.
. Medial joint line narrowing and accelerated trochlear wear.
. Asymmetric widening of the lateral ulnohumeral joint with capitellar wear.
. Proximal radioulnar synostosis with blocked supination.
. Posterolateral rotatory instability from stretching the LUCL.

Correct Answer & Explanation

. Asymmetric widening of the lateral ulnohumeral joint with capitellar wear.

Explanation

Overstuffing the radiocapitellar joint by inserting a radial head prosthesis that is too long causes altered elbow kinematics. It exerts excessive pressure on the capitellum, leading to rapid cartilage wear and subchondral osteolysis. Radiographically, this manifests as asymmetric widening of the ulnohumeral joint (specifically opening of the lateral aspect of the ulnohumeral articulation, creating a 'gap') because the radius is pushing the humerus away from the ulna. It also leads to a severe loss of elbow flexion and extension.

Question 934

Topic: Elbow & Forearm

A 30-year-old male presents with elbow pain and a mechanical click during extension and forearm supination following a fall. Examination reveals a positive lateral pivot-shift test. Which ligamentous structure is primarily deficient?

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

Correct Answer & Explanation

. Anterior bundle of the medial collateral ligament

Explanation

Posterolateral rotatory instability (PLRI) of the elbow is caused by insufficiency of the lateral ulnar collateral ligament (LUCL). The lateral pivot-shift test dynamically reproduces the characteristic subluxation and reduction of the radiocapitellar joint.

Question 935

Topic: Elbow & Forearm

A 14-year-old elite baseball pitcher presents with lateral elbow pain, clicking, and a 15-degree extension deficit. Radiographs reveal a radiolucent lesion of the capitellum with a sclerotic margin and a visible loose body in the joint. What is the most appropriate management?

. Rest and cessation of throwing for 6 weeks
. Arthroscopic debridement, loose body removal, and marrow stimulation
. Open reduction internal fixation of the capitellum
. Ulnar collateral ligament reconstruction
. Radial head excision

Correct Answer & Explanation

. Rest and cessation of throwing for 6 weeks

Explanation

In an adolescent with capitellar osteochondritis dissecans (OCD) presenting with a loose body and mechanical symptoms (indicating an unstable lesion), surgical intervention is required. Arthroscopic loose body removal and marrow stimulation (microfracture) is the standard of care.

Question 936

Topic: Elbow & Forearm

A 21-year-old collegiate pitcher undergoes a Tommy John surgery (UCL reconstruction). Which specific bundle of the Ulnar Collateral Ligament is the primary restraint to valgus stress at 90 degrees of flexion and is the primary target for this reconstruction?

. Anterior band of the anterior bundle
. Posterior band of the anterior bundle
. Posterior bundle
. Transverse ligament
. Oblique band

Correct Answer & Explanation

. Anterior band of the anterior bundle

Explanation

The anterior bundle of the UCL, specifically the anterior band, is the primary restraint to valgus stress between 30 and 120 degrees of elbow flexion. It is the critical structure reconstructed in Tommy John surgery.

Question 937

Topic: Elbow & Forearm

A 38-year-old female complains of a "clunking" sensation in her elbow when pushing up from a chair. A lateral pivot-shift test is performed to evaluate for posterolateral rotatory instability (PLRI). What is the specific mechanical subluxation that occurs during the provocation phase of this test?

. The radius and ulna subluxate posterolaterally away from the humerus
. The radius subluxates anteriorly from the capitellum
. The ulna subluxates posteromedially from the trochlea
. The radial head subluxates directly laterally
. The coronoid subluxates inferiorly

Correct Answer & Explanation

. The radius and ulna subluxate posterolaterally away from the humerus

Explanation

Posterolateral rotatory instability (PLRI) is due to lateral ulnar collateral ligament (LUCL) insufficiency. During the pivot-shift test, applying an axial load, valgus stress, and supination causes the radius and ulna to subluxate as a single unit posterolaterally off the humerus.

Question 938

Topic: Elbow & Forearm

Which ligamentous complex is the primary restraint to posterolateral rotatory instability (PLRI) of the elbow, frequently injured following a fall on an outstretched hand resulting in axial loading, valgus, and supination forces?

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

Correct Answer & Explanation

. Anterior bundle of the medial ulnar collateral ligament

Explanation

The lateral ulnar collateral ligament (LUCL) is the primary restraint to posterolateral rotatory instability of the elbow. Reconstruction or repair of this specific structure is critical to restoring stability.

Question 939

Topic: Elbow & Forearm

A 40-year-old male sustains a severely comminuted radial head fracture and a concomitant distal radioulnar joint (DRUJ) disruption (Essex-Lopresti injury). If the radial head is completely excised without prosthetic replacement, what is the most likely late mechanical complication?

. Heterotopic ossification of the interosseous membrane
. Proximal migration of the radius causing ulnocarpal impingement
. Severe cubitus varus deformity
. Isolated elbow extension deficit
. Posterolateral rotatory instability

Correct Answer & Explanation

. Heterotopic ossification of the interosseous membrane

Explanation

In an Essex-Lopresti injury, the interosseous membrane is disrupted. Excision of the radial head removes the proximal longitudinal restraint, leading to proximal radial migration and painful ulnocarpal impingement.

Question 940

Topic: Elbow & Forearm

A 6-year-old boy presents with a displaced lateral condyle fracture of the humerus. Which of the following is the most common long-term complication if this fracture goes on to nonunion?

. Cubitus varus
. Anterior interosseous nerve palsy
. Tardy ulnar nerve palsy
. Avascular necrosis of the capitellum
. Premature closure of the medial epicondyle

Correct Answer & Explanation

. Cubitus varus

Explanation

Nonunion of a lateral condyle fracture typically results in a progressive cubitus valgus deformity. This valgus angulation stretches the ulnar nerve over time, leading to tardy ulnar nerve palsy.

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