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9. Shoulder and Elbow MCQs

Practice Set 72 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 1421

Topic: 9. Shoulder and Elbow
Which of the following structures is the most important restraint to posterior subluxation of the glenohumeral joint when positioned in 90 degrees of flexion and internal rotation?
. Subscapularis muscle and tendon
. Supraspinatus muscle and tendon
. Middle glenohumeral ligament
. Inferior glenohumeral ligament
. Coracohumeral ligament

Correct Answer & Explanation

. Inferior glenohumeral ligament

Explanation

The posterior band of the inferior glenohumeral ligament is the most important restraint to posterior subluxation of the glenohumeral joint with the shoulder in 90 degrees of flexion and internal rotation. With the shoulder in external rotation, the subscapularis is an important stabilizer to posterior subluxation. When the shoulder is in neutral rotation, the coracohumeral ligament is the primary stabilizer.

Question 1422

Topic: 9. Shoulder and Elbow
A 44-year-old man who sustained an elbow dislocation 3 months ago now reports pain and restricted elbow motion. Radiographs are shown in Figures 27a and 27b. Management should consist of:
. closed reduction and casting.
. static splinting.
. open reduction and lateral collateral ligament reconstruction.
. open reduction and lateral collateral ligament repair.
. open reduction, application of a hinged external fixator, and radial head arthroplasty.

Correct Answer & Explanation

. open reduction, application of a hinged external fixator, and radial head arthroplasty.

Explanation

The treatment of choice for an ankylosed chronically dislocated elbow is surgical reduction. Open reduction with application of an external fixator provides excellent results for this complex problem. Attempts at closed reduction will be unsuccessful and should not be attempted in a stiff elbow.

Question 1423

Topic: 9. Shoulder and Elbow

A 40-year-old male sustains a high-energy floating shoulder injury (ipsilateral clavicle and scapular neck fractures). Measurement of the glenopolar angle (GPA) on an AP radiograph of the shoulder is considered. Which of the following statements regarding the GPA is correct?

. The normal GPA is 10 to 20 degrees, and a GPA > 45 degrees is an indication for surgery
. The normal GPA is 30 to 45 degrees, and a GPA < 20 degrees is an indication for surgery
. The GPA is measured between the coracoid process and the inferior angle of the scapula
. The GPA evaluates the medial displacement of the clavicle relative to the coracoid
. The normal GPA is 50 to 60 degrees, and a GPA < 30 degrees signifies an intact suspensory complex

Correct Answer & Explanation

. The normal GPA is 30 to 45 degrees, and a GPA < 20 degrees is an indication for surgery

Explanation

The glenopolar angle (GPA) assesses rotational malalignment of the glenoid in scapular neck fractures. It is the angle formed by a line connecting the superior and inferior glenoid rims and a line connecting the superior glenoid rim to the inferior angle of the scapula. Normal GPA is 30 to 45 degrees. A severely decreased GPA (typically < 20-22 degrees) implies severe inferior tilt of the glenoid and is widely accepted as an indication for operative fixation to prevent chronic shoulder dysfunction.

Question 1424

Topic: Elbow & Forearm

A 35-year-old patient sustains a 'terrible triad' injury of the elbow. Standard surgical protocol dictates a specific order of repair to restore stability. Which of the following represents the most accepted surgical sequence?

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

Correct Answer & Explanation

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

Explanation

The standard sequence for treating a terrible triad injury is to fix from deep to superficial. This involves restoring the anterior column (coronoid) first, followed by the radial head, and finally the lateral collateral ligament (LCL) complex.

Question 1425

Topic: 9. Shoulder and Elbow

A 42-year-old male sustains a terrible triad injury of the elbow. During surgical reconstruction, what is the most widely accepted standard sequence of repair to restore elbow stability?

. LCL repair, radial head fixation, coronoid fixation
. Coronoid fixation, radial head fixation/replacement, LCL repair
. Radial head fixation/replacement, LCL repair, coronoid fixation
. Coronoid fixation, LCL repair, radial head fixation/replacement
. LCL repair, coronoid fixation, radial head fixation/replacement

Correct Answer & Explanation

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

Explanation

The standard surgical algorithm for a terrible triad injury (elbow dislocation, radial head fracture, coronoid fracture) typically proceeds from deep to superficial, or anterior to posterior: 1) Fixation or capsular repair of the coronoid, 2) Fixation or replacement of the radial head, 3) Repair of the lateral collateral ligament (LCL) complex. If the elbow remains unstable after these steps, the medial collateral ligament (MCL) repair or application of a hinged external fixator may be considered.

Question 1426

Topic: Elbow & Forearm
A 40-year-old woman falls on an outstretched hand and sustains a coronal shear fracture of the distal humerus. CT imaging reveals that the fracture fragment includes the capitellum and extends medially to include the majority of the trochlea. According to the McKee modification of the Bryan and Morrey classification, what type of fracture is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type IV

Explanation

The Bryan and Morrey classification describes capitellum fractures. Type I (Hahn-Steinthal) is a large capitellar fragment with substantial subchondral bone. Type II (Kocher-Lorenz) involves articular cartilage with minimal subchondral bone. Type III (Broberg-Morrey) is comminuted. McKee added Type IV, which is a coronal shear fracture that involves the capitellum and extends medially to include most or all of the trochlea.

Question 1427

Topic: 9. Shoulder and Elbow

During an ulnar collateral ligament (UCL) reconstruction of the elbow using the docking technique, the surgeon must be careful to avoid injury to the primary dynamic stabilizer against valgus stress. Which of the following muscles acts as the primary dynamic valgus stabilizer of the elbow?

. Pronator teres
. Flexor carpi ulnaris
. Flexor digitorum superficialis
. Extensor carpi radialis brevis
. Brachioradialis

Correct Answer & Explanation

. Flexor carpi ulnaris

Explanation

While the anterior bundle of the UCL is the primary static stabilizer against valgus stress at the elbow, the flexor carpi ulnaris (FCU) and the flexor digitorum superficialis (FDS) are the primary dynamic stabilizers. Biomechanical studies have shown that the flexor carpi ulnaris provides the greatest dynamic stabilization against valgus forces during the throwing motion.

Question 1428

Topic: Elbow & Forearm

A patient complains of elbow clicking and a sense of giving way when pushing out of a chair. The lateral pivot-shift test of the elbow reproduces the symptoms. This instability pattern (PLRI) is primarily caused by insufficiency of which of the following structures?

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

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL)

Explanation

Posterolateral rotatory instability (PLRI) of the elbow is the most common pattern of chronic elbow instability. It is classically caused by insufficiency or rupture of the lateral ulnar collateral ligament (LUCL). The LUCL serves as the primary restraint to posterolateral subluxation of the radial head and proximal ulna relative to the humerus.

Question 1429

Topic: Elbow & Forearm

A 45-year-old male sustains an acute distal biceps tendon rupture while lifting a heavy box. A double-incision (modified Boyd-Anderson) repair technique is chosen. Compared to a single-incision anterior approach, the double-incision technique carries a statistically higher risk of which of the following specific complications?

. Lateral antebrachial cutaneous (LABC) nerve palsy
. Posterior interosseous nerve (PIN) palsy
. Proximal radioulnar synostosis
. Re-rupture of the tendon
. Median nerve entrapment

Correct Answer & Explanation

. Proximal radioulnar synostosis

Explanation

The double-incision approach was developed to avoid the radial nerve and lateral antebrachial cutaneous (LABC) nerve injuries associated with the single anterior incision. However, it requires dissection through the interosseous membrane or around the ulna, which carries a higher risk of heterotopic ossification and proximal radioulnar synostosis compared to a single-incision approach. Single-incision approaches have a higher rate of LABC nerve neuropraxia.

Question 1430

Topic: 9. Shoulder and Elbow

A 55-year-old female sustains a terrible triad injury of the elbow. Intraoperatively, the coronoid fracture is fixed with a suture lasso, the irreparable radial head is replaced with a metallic arthroplasty, and the lateral ulnar collateral ligament (LUCL) is repaired to the lateral epicondyle. During examination under anesthesia, the elbow hinges open on the medial side and subluxates when extended beyond 30 degrees. What is the most appropriate next step?

. Apply a hinged external fixator immediately
. Repair the medial ulnar collateral ligament (MUCL)
. Repair the common extensor origin
. Pin the radiocapitellar joint
. Perform an ulnohumeral arthrodesis

Correct Answer & Explanation

. Repair the medial ulnar collateral ligament (MUCL)

Explanation

The standard surgical algorithm for a terrible triad injury is deep to superficial, fixing the coronoid, then addressing the radial head, and finally repairing the lateral collateral ligament complex. If the elbow remains unstable in extension after these steps, the next appropriate step is exploration and repair of the medial ulnar collateral ligament (MUCL). If instability persists despite MUCL repair, a hinged external fixator is indicated.

Question 1431

Topic: 9. Shoulder and Elbow

A 22-year-old elite baseball pitcher presents with medial elbow pain during the late cocking phase of throwing. MRI demonstrates a high-grade partial tear of the medial ulnar collateral ligament (MUCL). Which component of the MUCL is the primary restraint to valgus stress at the elbow between 30 and 120 degrees of flexion?

. Anterior bundle
. Posterior bundle
. Transverse bundle
. Radial collateral ligament
. Annular ligament

Correct Answer & Explanation

. Anterior bundle

Explanation

The anterior bundle of the medial ulnar collateral ligament (MUCL) is the primary restraint to valgus stress at the elbow from 30 to 120 degrees of flexion. The posterior bundle acts as a secondary restraint, becoming taut in higher degrees of flexion. The transverse bundle provides no significant contribution to elbow stability.

Question 1432

Topic: Elbow & Forearm

A 35-year-old female complains of recurrent elbow clicking and a sense of instability when pushing up from a chair. Examination reveals a positive lateral pivot-shift test of the elbow. This condition is most directly caused by insufficiency of which of the following structures?

. Radial collateral ligament
. Lateral ulnar collateral ligament
. Annular ligament
. Anterior bundle of the medial collateral ligament
. Extensor carpi radialis brevis origin

Correct Answer & Explanation

. Lateral ulnar collateral ligament

Explanation

Posterolateral rotatory instability (PLRI) is the most common form of recurrent elbow instability. It is caused by insufficiency of the lateral ulnar collateral ligament (LUCL), which allows the radial head to subluxate posterolaterally.

Question 1433

Topic: Elbow & Forearm

A 40-year-old male undergoes a two-incision distal biceps tendon repair. Compared to a single-incision anterior approach, the two-incision technique is historically associated with a higher risk of which of the following complications?

. Lateral antebrachial cutaneous nerve palsy
. Posterior interosseous nerve palsy
. Radioulnar synostosis
. Median nerve neuropraxia
. Re-rupture of the repaired tendon

Correct Answer & Explanation

. Radioulnar synostosis

Explanation

The two-incision (modified Boyd-Anderson) approach was developed to decrease radial nerve injuries but is associated with a higher risk of heterotopic ossification and radioulnar synostosis due to subperiosteal dissection near the ulna. Single-incision repairs carry a higher risk to the lateral antebrachial cutaneous nerve (LABCN).

Question 1434

Topic: Elbow & Forearm

A 32-year-old gymnast reports recurrent clicking and catching in her lateral elbow when pushing up from a chair. The lateral pivot-shift test of the elbow is positive. Which ligamentous structure is primarily incompetent?

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

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL)

Explanation

Posterolateral rotatory instability (PLRI) of the elbow is caused by insufficiency of the lateral ulnar collateral ligament (LUCL). The patient typically presents with symptoms during axial loading, supination, and valgus stress (e.g., pushing off a chair).

Question 1435

Topic: Elbow & Forearm

A 40-year-old female presents with an elbow injury. Lateral radiographs show the "double-arc" sign. Which of the following best describes this fracture pattern?

. Radial head fracture with a posterior elbow dislocation
. Isolated fracture of the articular cartilage of the capitellum (Kocher-Lorenz)
. Coronal shear fracture involving both the capitellum and the lateral ridge of the trochlea (McKee type)
. Supracondylar humerus fracture with anterior displacement
. Fracture of the olecranon extending into the coronoid

Correct Answer & Explanation

. Coronal shear fracture involving both the capitellum and the lateral ridge of the trochlea (McKee type)

Explanation

The "double-arc" sign on a lateral elbow radiograph is pathognomonic for a Type IV (McKee) coronal shear fracture, indicating involvement of both the capitellum and the lateral trochlear ridge. Anatomic reduction and rigid internal fixation are required.

Question 1436

Topic: 9. Shoulder and Elbow

A 42-year-old bodybuilder undergoes a two-incision repair for an acute distal biceps tendon rupture. Postoperatively, he has normal elbow flexion but struggles with forearm pronation and supination due to a mechanical block. Which complication is most likely responsible?

. Posterior interosseous nerve (PIN) palsy
. Lateral antebrachial cutaneous nerve (LABC) neuroma
. Radioulnar synostosis
. Recurrent rupture of the biceps tendon
. Heterotopic ossification of the brachialis muscle

Correct Answer & Explanation

. Radioulnar synostosis

Explanation

A known complication of the two-incision technique for distal biceps repair is radioulnar synostosis, which presents as a mechanical block to pronation/supination. The risk is minimized by avoiding subperiosteal dissection of the ulna and muscle-splitting of the supinator.

Question 1437

Topic: Elbow & Forearm

In a Dubberley Type 3B fracture of the capitellum, what specific anatomic characteristic dictates the need for a more complex reconstructive strategy compared to a Type 3A fracture?

. The presence of posterior capitellar comminution
. Involvement of the radial head
. Disruption of the lateral ulnar collateral ligament
. Associated fracture of the coronoid process
. Avulsion of the triceps insertion

Correct Answer & Explanation

. The presence of posterior capitellar comminution

Explanation

The Dubberley classification differentiates capitellar/trochlear fractures based on the presence (Type B) or absence (Type A) of posterior capitellar comminution. Type B fractures lack a stable posterior bony buttress, often requiring structural bone grafting or specialized posterior to anterior fixation to prevent collapse.

Question 1438

Topic: Elbow & Forearm

During surgical reconstruction of the lateral ulnar collateral ligament (LUCL) for posterolateral rotatory instability of the elbow, accurate placement of the humeral tunnel is critical. Where is the optimal isometric point for the humeral attachment?

. Anterior and proximal to the lateral epicondyle
. At the center of curvature of the capitellum
. Directly at the insertion of the extensor carpi radialis brevis
. On the supracondylar ridge 2 cm proximal to the joint line
. At the sublime tubercle

Correct Answer & Explanation

. At the center of curvature of the capitellum

Explanation

The isometric point for LUCL reconstruction on the humerus is located at the center of curvature of the capitellum, which typically lies just distal and anterior to the lateral epicondyle tip. Non-isometric placement will result in graft stretching or restricted range of motion.

Question 1439

Topic: Shoulder Pathology

A 30-year-old female presents with progressive right shoulder weakness and a dull ache following a cervical lymph node biopsy performed three months ago. On examination, when she attempts to push against a wall with her arms elevated, the medial border of her right scapula translates laterally and superiorly. Injury to which of the following nerves and corresponding muscle deficit is most likely responsible for her condition?

. Long thoracic nerve; Serratus anterior
. Spinal accessory nerve; Trapezius
. Dorsal scapular nerve; Rhomboids
. Suprascapular nerve; Supraspinatus
. Axillary nerve; Deltoid

Correct Answer & Explanation

. Spinal accessory nerve; Trapezius

Explanation

The patient is exhibiting 'lateral winging' of the scapula (the scapula translates laterally and superiorly), which is the hallmark of trapezius muscle paralysis due to spinal accessory nerve (Cranial Nerve XI) injury. This nerve is superficially located in the posterior triangle of the neck and is highly susceptible to iatrogenic injury during lymph node biopsies. In contrast, 'medial winging' (prominence of the medial border translating medially) is associated with serratus anterior weakness secondary to long thoracic nerve injury.

Question 1440

Topic: 9. Shoulder and Elbow

Which of the following best describes the fundamental biomechanical alteration achieved by the Grammont-style Reverse Total Shoulder Arthroplasty (rTSA) compared to the native glenohumeral joint?

. Medialization and superior translation of the center of rotation
. Lateralization and superior translation of the center of rotation
. Medialization and inferior translation of the center of rotation
. Lateralization and inferior translation of the center of rotation
. No change in the center of rotation but an increase in conformity

Correct Answer & Explanation

. Medialization and inferior translation of the center of rotation

Explanation

The Grammont design of the Reverse Total Shoulder Arthroplasty (rTSA) works by medializing and distalizing (inferior translation) the center of rotation of the glenohumeral joint. This alteration significantly increases the moment arm of the deltoid muscle and increases deltoid fiber recruitment, allowing it to compensate for a deficient rotator cuff to achieve active arm elevation.

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