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9. Shoulder and Elbow MCQs

Practice Set 65 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 1281

Topic: Elbow & Forearm

A 38-year-old male undergoes surgical repair of a complete distal biceps tendon rupture using a single-incision anterior approach. Postoperatively, he complains of numbness over the radial aspect of his volar forearm. Which structure was most likely injured during the procedure?

. Posterior interosseous nerve
. Superficial radial nerve
. Lateral antebrachial cutaneous nerve
. Medial antebrachial cutaneous nerve
. Median nerve

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve

Explanation

The lateral antebrachial cutaneous nerve (LABCN) runs closely alongside the cephalic vein and biceps tendon distally. It is the most commonly injured neurologic structure during a single-incision anterior approach for distal biceps repair.

Question 1282

Topic: Elbow & Forearm

A 28-year-old female complains of recurrent clicking and a sense of instability in her elbow when pushing up from a chair. Physical examination reveals apprehension during a pivot-shift test. This condition is primarily due to insufficiency of which of the following structures?

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

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL)

Explanation

Posterolateral rotatory instability (PLRI) of the elbow presents with a positive lateral pivot-shift test and apprehension when extending the elbow with supination and an axial load. It is primarily caused by an incompetent lateral ulnar collateral ligament (LUCL).

Question 1283

Topic: Elbow & Forearm

A 45-year-old male falls from a height and sustains a comminuted radial head fracture, along with significant wrist pain. Radiographs show proximal migration of the radius. If the radial head is resected without replacement in this setting, what is the most likely biomechanical consequence?

. Increased radiocapitellar joint pressure
. Distal radioulnar joint (DRUJ) instability and ulnocarpal impaction
. Varus elbow instability
. Posterolateral rotatory instability
. Decreased load transmission through the interosseous membrane

Correct Answer & Explanation

. Distal radioulnar joint (DRUJ) instability and ulnocarpal impaction

Explanation

This presentation describes an Essex-Lopresti injury (radial head fracture, interosseous membrane tear, DRUJ disruption). Resecting the radial head without replacement eliminates the proximal block to migration, resulting in severe proximal radial migration and secondary ulnocarpal impaction.

Question 1284

Topic: Elbow & Forearm

Following an unsalvageable radial head fracture, a metallic radial head arthroplasty is planned. To prevent overstuffing the radiocapitellar joint, the proximal articular surface of the radial head implant should ideally be placed at which anatomic landmark relative to the proximal radioulnar joint (PRUJ)?

. 2 mm proximal to the lateral edge of the coronoid articular surface
. Flush with or slightly proximal (within 1-2 mm) to the lateral edge of the lesser sigmoid notch
. 5 mm distal to the capitellum in full extension
. Flush with the tip of the olecranon
. 3 mm proximal to the annular ligament insertion

Correct Answer & Explanation

. Flush with or slightly proximal (within 1-2 mm) to the lateral edge of the lesser sigmoid notch

Explanation

To restore proper elbow kinematics and avoid overstuffing, the proximal rim of the radial head implant should be placed flush with, or no more than 1-2 mm proximal to, the lateral edge of the lesser sigmoid notch of the ulna.

Question 1285

Topic: Elbow & Forearm

A 32-year-old female sustains a coronal shear fracture of the distal humerus that involves the capitellum and the lateral half of the trochlea. Which classification accurately describes this fracture pattern?

. Hahn-Steinthal (Type I)
. Kocher-Lorenz (Type II)
. Broberg-Morrey Type I
. McKee modification of Bryan-Morrey Type IV
. Milch Type I

Correct Answer & Explanation

. McKee modification of Bryan-Morrey Type IV

Explanation

The McKee modification of the Bryan-Morrey classification describes a Type IV fracture as a coronal shear fracture that involves the capitellum and extends medially to include the lateral portion of the trochlea. This creates a pathognomonic 'double-arc' sign on a lateral radiograph.

Question 1286

Topic: 9. Shoulder and Elbow

A 50-year-old female with poorly controlled type 2 diabetes presents with progressive, painful restriction of active and passive shoulder motion. What is the predominant histological finding in the joint capsule of a patient with this condition?

. Acute inflammatory infiltrate with neutrophils
. Mononuclear cells with perivascular cuffing
. Proliferation of fibroblasts and myofibroblasts
. Fibrinoid necrosis of the synovium
. Chondroid metaplasia

Correct Answer & Explanation

. Proliferation of fibroblasts and myofibroblasts

Explanation

Adhesive capsulitis is characterized primarily by fibroplasia rather than acute inflammation. The predominant histological finding is a dense proliferation of fibroblasts and myofibroblasts within the joint capsule, leading to contracture.

Question 1287

Topic: 9. Shoulder and Elbow

A 40-year-old male undergoes radial head arthroplasty for a severely comminuted radial head fracture. Overstuffing the radiocapitellar joint during this procedure will most likely lead to which of the following complications?

. Capitellar erosion and early osteoarthritis
. Medial collateral ligament laxity
. Proximal radioulnar joint instability
. Ulnar nerve traction injury
. Early loosening of the ulnar stem

Correct Answer & Explanation

. Capitellar erosion and early osteoarthritis

Explanation

Overstuffing the radiocapitellar joint with an oversized radial head implant increases radiocapitellar contact pressures. This leads to capitellar erosion, stiffness, early osteoarthritis, and gapping of the medial elbow compartment.

Question 1288

Topic: Elbow & Forearm

Which tendon is most commonly and primarily involved in the underlying pathoanatomy of lateral epicondylitis (tennis elbow)?

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

Correct Answer & Explanation

. Extensor carpi radialis brevis

Explanation

Lateral epicondylitis is characterized by angiofibroblastic hyperplasia primarily occurring at the origin of the extensor carpi radialis brevis (ECRB) tendon.

Question 1289

Topic: Shoulder Pathology

A 26-year-old female presents with lateral scapular winging and an inability to actively abduct her arm past 90 degrees. She recently underwent a lymph node biopsy in the posterior cervical triangle. Which nerve was most likely injured?

. Spinal accessory nerve
. Long thoracic nerve
. Dorsal scapular nerve
. Suprascapular nerve
. Axillary nerve

Correct Answer & Explanation

. Spinal accessory nerve

Explanation

Injury to the spinal accessory nerve (CN XI) paralyzes the trapezius muscle, leading to a drooping shoulder, lateral winging of the scapula, and weakness in shoulder abduction. It is a known complication of surgical procedures in the posterior cervical triangle.

Question 1290

Topic: Elbow & Forearm

A 42-year-old male sustains an Essex-Lopresti injury characterized by a comminuted radial head fracture, rupture of the interosseous membrane, and disruption of the distal radioulnar joint (DRUJ). In the acute setting, what is the most appropriate management of the radial head?

. Radial head excision alone
. Radial head excision with primary DRUJ pinning
. Radial head arthroplasty
. Closed reduction and casting in supination
. Radial head fragment excision and primary repair of the annular ligament

Correct Answer & Explanation

. Radial head arthroplasty

Explanation

In an Essex-Lopresti injury, longitudinal forearm stability is lost due to interosseous membrane rupture. The radial head must be preserved or replaced (radial head arthroplasty) to prevent proximal migration of the radius and chronic wrist pain. Radial head excision is absolutely contraindicated.

Question 1291

Topic: Shoulder Arthroplasty & Arthritis

In reverse total shoulder arthroplasty, moving the center of rotation medially and inferiorly alters the biomechanics of the deltoid. Which of the following best describes this effect?

. Increases the deltoid moment arm and decreases deltoid tension
. Increases the deltoid moment arm and increases deltoid tension
. Decreases the deltoid moment arm and increases deltoid tension
. Decreases the deltoid moment arm and decreases deltoid tension
. Has no effect on the deltoid moment arm

Correct Answer & Explanation

. Increases the deltoid moment arm and increases deltoid tension

Explanation

The Grammont design of rTSA medializes and distalizes the center of rotation. This increases the deltoid moment arm, which improves its mechanical advantage, and increases deltoid tension, which improves stability and recruits more anterior and posterior deltoid fibers for elevation.

Question 1292

Topic: Elbow & Forearm

A 45-year-old male sustains a terrible triad injury to the elbow. During surgical management, which of the following sequences of repair provides the most biomechanically sound restoration of stability?

. LCL repair, radial head fixation/replacement, 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 involves repairing structures from deep to superficial, or "inside-out". The sequence is typically: 1) Coronoid fixation, 2) Radial head fixation or arthroplasty, 3) LCL complex repair to the lateral epicondyle. If the elbow remains unstable after these steps, the MCL can be repaired or an external fixator applied.

Question 1293

Topic: 9. Shoulder and Elbow

A 62-year-old man presents with vague shoulder pain 18 months after a total shoulder arthroplasty. Inflammatory markers (ESR, CRP) are normal. Aspiration yields no growth at 3 days. What is the optimal approach to diagnose a suspected Cutibacterium acnes (C. acnes) infection?

. Repeat aspiration and culture for 5 days
. Hold cultures for a minimum of 14 days in both aerobic and anaerobic conditions
. Perform a tagged white blood cell scan
. Proceed with empiric intravenous vancomycin
. Measure serum interleukin-6 levels

Correct Answer & Explanation

. Hold cultures for a minimum of 14 days in both aerobic and anaerobic conditions

Explanation

C. acnes is an indolent, slow-growing, anaerobic Gram-positive bacillus that is a common cause of periprosthetic shoulder infections. It frequently presents with normal inflammatory markers. To properly identify C. acnes, cultures should be held for at least 14 days, as it often does not grow in standard 3- to 5-day culture periods.

Question 1294

Topic: Shoulder Arthroplasty & Arthritis

Which of the following component positioning strategies is most effective at reducing the incidence of scapular notching in reverse total shoulder arthroplasty?

. Superior placement of the glenosphere and neutral tilt
. Medialization of the glenosphere and superior tilt
. Inferior placement of the glenosphere with an inferior tilt
. Decreasing the lateral offset of the glenosphere
. Increasing the neck-shaft angle of the humeral component to 155 degrees

Correct Answer & Explanation

. Inferior placement of the glenosphere with an inferior tilt

Explanation

Scapular notching is a frequent complication of rTSA where the medial aspect of the humeral tray impinges on the inferior scapular neck. To minimize notching, the glenosphere should be placed inferiorly (overhanging the inferior glenoid rim) and tilted inferiorly. Lateralizing the center of rotation (either with a lateralized glenosphere or bone graft) and decreasing the humeral neck-shaft angle (e.g., to 135 or 145 degrees instead of 155) also reduce notching.

Question 1295

Topic: Elbow & Forearm

A patient presents with a history of recurrent elbow clicking and a sense of instability when pushing up from a chair. A lateral pivot-shift test of the elbow is positive. This condition is primarily caused by insufficiency of which of the following structures?

. Anterior bundle of the medial collateral ligament
. Lateral ulnar collateral ligament (LUCL)
. Annular ligament
. Radial collateral ligament
. Common extensor origin

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL)

Explanation

Posterolateral rotatory instability (PLRI) of the elbow is typically caused by injury or insufficiency of the lateral ulnar collateral ligament (LUCL). The LUCL is the primary restraint to posterolateral rotatory subluxation of the radiocapitellar joint. Patients often describe symptoms when applying axial load, valgus stress, and supination (e.g., pushing off a chair).

Question 1296

Topic: Shoulder Arthroplasty & Arthritis

A 65-year-old female is scheduled for a total shoulder arthroplasty for primary osteoarthritis. Preoperative CT reveals a Walch B2 glenoid. What does a B2 glenoid signify, and what is a common surgical strategy for addressing it in anatomic TSA?

. Central wear with intact margins; addressed by concentric reaming.
. Biconcave glenoid with posterior wear; addressed by asymmetric reaming to correct retroversion, or bone grafting/augmented components if wear is severe.
. Dysplastic glenoid with severe retroversion (>25 degrees); requires reverse TSA.
. Anterior wear with anterior subluxation; requires anterior bone grafting.
. Superior migration of the humeral head; requires reverse TSA.

Correct Answer & Explanation

. Biconcave glenoid with posterior wear; addressed by asymmetric reaming to correct retroversion, or bone grafting/augmented components if wear is severe.

Explanation

The Walch classification describes glenoid morphology. A B2 glenoid is characterized by asymmetric posterior wear creating a biconcave surface and posterior subluxation of the humeral head. In anatomic TSA, this can be addressed by asymmetric anterior reaming (up to 10-15 degrees of retroversion correction, provided enough subchondral bone remains), posterior bone grafting, or using a posteriorly augmented glenoid component. If correction isn't possible without violating the glenoid vault, rTSA is indicated.

Question 1297

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old male presents with inability to actively elevate his right arm past 45 degrees, despite having full passive range of motion. MRI demonstrates a massive, retracted tear of the supraspinatus and infraspinatus with Goutallier grade 4 fatty infiltration. The subscapularis and teres minor are intact. What is the most appropriate definitive surgical intervention?

. Arthroscopic primary rotator cuff repair
. Superior capsular reconstruction
. Latissimus dorsi tendon transfer
. Reverse total shoulder arthroplasty
. Anatomic total shoulder arthroplasty

Correct Answer & Explanation

. Reverse total shoulder arthroplasty

Explanation

This patient presents with pseudoparalysis (inability to actively elevate >90 degrees with preserved passive motion) secondary to a massive, irreparable rotator cuff tear (Goutallier 4 fatty infiltration implies irreversibility and irreparability). In an older patient with pseudoparalysis and an irreparable tear, reverse total shoulder arthroplasty (rTSA) is the treatment of choice, as it relies on the deltoid for elevation and does not require a functioning superior rotator cuff. Superior capsular reconstruction or tendon transfers are less predictable for reversing true pseudoparalysis in the elderly, and anatomic TSA is contraindicated in the absence of a functional cuff.

Question 1298

Topic: Elbow & Forearm

When performing a two-incision repair for a distal biceps tendon rupture (modified Morrey approach), which of the following nerves is at the greatest risk of injury during the creation of the posterior bone tunnel in the radial tuberosity?

. Lateral antebrachial cutaneous nerve
. Posterior interosseous nerve (PIN)
. Anterior interosseous nerve (AIN)
. Superficial radial nerve
. Ulnar nerve

Correct Answer & Explanation

. Posterior interosseous nerve (PIN)

Explanation

The two-incision approach for distal biceps repair was developed to decrease the risk of injury to the radial nerve/PIN seen in a single-incision anterior approach. However, if the forearm is not kept in maximal pronation during the creation of the posterior bone tunnel (when exiting the ulna/radius posterolaterally), the PIN can wrap around the radial neck and be injured. Maximal pronation moves the PIN away from the surgical field.

Question 1299

Topic: Shoulder Arthroplasty & Arthritis

A 70-year-old female presents with sudden, sharp shoulder pain 6 months after an uncomplicated reverse total shoulder arthroplasty (rTSA). Radiographs reveal a new stress fracture of the acromion base (Levy Type II). What biomechanical factor of the rTSA construct most significantly contributed to this complication?

. Superior positioning of the glenosphere
. Medialization of the center of rotation
. Excessive lengthening of the humerus (increased deltoid tension)
. Undersizing of the humeral stem
. Use of a cemented humeral stem

Correct Answer & Explanation

. Excessive lengthening of the humerus (increased deltoid tension)

Explanation

Acromial stress fractures after rTSA occur due to the altered biomechanics and increased tension on the deltoid, which originates on the acromion. Excessive distalization (lengthening of the humerus) significantly increases deltoid resting tension, placing a high load on the acromion and increasing the risk of a stress fracture. Other factors include superior screw placement in the base of the acromion or severe osteoporosis.

Question 1300

Topic: Shoulder Arthroplasty & Arthritis

To minimize the risk of scapular notching in reverse total shoulder arthroplasty (RTSA), how should the glenosphere baseplate optimally be positioned?

. Superior translation and superior tilt
. Inferior translation and superior tilt
. Superior translation and inferior tilt
. Inferior translation and inferior tilt
. Neutral translation and superior tilt

Correct Answer & Explanation

. Inferior translation and inferior tilt

Explanation

Scapular notching is a well-known complication of RTSA resulting from mechanical impingement of the humeral component against the inferior scapular neck during arm adduction. Positioning the glenosphere with inferior translation (overhanging the inferior rim) and inferior tilt alters the biomechanics to increase the impingement-free range of motion and drastically reduces the incidence of notching.

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