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9. Shoulder and Elbow MCQs

Practice Set 75 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 1481

Topic: 9. Shoulder and Elbow

A 45-year-old male undergoes radial head arthroplasty for a highly comminuted radial head fracture. Intraoperatively, the surgeon inadvertently inserts an implant that is 3 mm longer than the native radial head. What is the most likely clinical consequence of 'overstuffing' the radiocapitellar joint?

. Varus instability
. Medial collateral ligament attenuation
. Capitellar erosion and loss of elbow flexion
. Posterior interosseous nerve palsy
. Distal radioulnar joint instability

Correct Answer & Explanation

. Capitellar erosion and loss of elbow flexion

Explanation

Overstuffing the radial head causes pathologically increased radiocapitellar contact pressures. This leads to capitellar cartilage erosion, early arthritis, lateral elbow pain, and a mechanical loss of elbow flexion and extension.

Question 1482

Topic: Shoulder Arthroplasty & Arthritis

A 70-year-old female presents with new-onset lateral shoulder pain 4 months after undergoing an uncomplicated reverse total shoulder arthroplasty (RTSA). Radiographs demonstrate a Levy Type II acromial stress fracture at the base of the acromion. What is the most appropriate initial management?

. Revision arthroplasty using a smaller glenosphere
. Open reduction and internal fixation with a locked plate
. Sling immobilization and symptomatic conservative care
. Corticosteroid injection into the subacromial space
. Conversion to an anatomic hemiarthroplasty

Correct Answer & Explanation

. Sling immobilization and symptomatic conservative care

Explanation

Levy Type II acromial stress fractures (located at the base of the acromion) following RTSA are typically managed nonoperatively in the initial stages with a sling and conservative care. Surgery is generally reserved for severe, progressive displacement or symptomatic nonunion after an adequate trial of conservative management, due to the high complication rates associated with internal fixation of these osteopenic fractures.

Question 1483

Topic: 9. Shoulder and Elbow

A 65-year-old male with primary glenohumeral osteoarthritis presents for anatomic total shoulder arthroplasty (TSA). Preoperative CT scanning demonstrates a Walch B2 glenoid with 22 degrees of retroversion and posterior humeral head subluxation. During the procedure, which strategy best addresses the glenoid deformity while minimizing the risk of early component loosening?

. High-side anterior eccentric reaming to correct version to exactly 0 degrees
. Implantation of a standard pegged glenoid with posterior cement build-up
. Use of a posteriorly augmented step-cut or wedge glenoid component
. Conversion to a resurfacing hemiarthroplasty with concentric reaming
. Standard reaming following the native retroverted paleoglenoid version

Correct Answer & Explanation

. Use of a posteriorly augmented step-cut or wedge glenoid component

Explanation

In Walch B2 glenoids with severe retroversion (>15 degrees), high-side anterior eccentric reaming to achieve neutral version removes excessive subchondral bone, risking peg or keel perforation into the vault and compromising fixation. The use of augmented (posteriorly stepped or wedged) glenoid components allows for correction of retroversion while preserving critical anterior glenoid bone stock, reducing the risk of component loosening.

Question 1484

Topic: Elbow & Forearm

A 45-year-old male sustains a terrible triad injury of the elbow. He undergoes operative management comprising radial head replacement, coronoid fracture fixation, and lateral ulnar collateral ligament (LUCL) repair. What is the most appropriate early postoperative rehabilitation protocol to maintain stability while promoting motion?

. Early active extension in forearm supination to protect the medial complex
. Active extension in forearm pronation, and flexion in any forearm position
. Immobilization in 90 degrees of flexion and full supination for 6 continuous weeks
. Passive range of motion only for the first 4 weeks to allow ligamentous healing
. Immediate varus and valgus stress testing at full extension to ensure ligament integrity

Correct Answer & Explanation

. Active extension in forearm pronation, and flexion in any forearm position

Explanation

Following a terrible triad repair (which intrinsically involves LUCL repair), early active motion is preferred to prevent stiffness. Active extension should be performed with the forearm in pronation. Pronation engages the radial head against the capitellum and protects the repaired lateral collateral ligament complex from excessive varus and posterolateral rotatory stress. Flexion is generally safe in any forearm position.

Question 1485

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old male who underwent a reverse total shoulder arthroplasty (RTSA) returns for his 3-year follow-up. Radiographs demonstrate a Sirveaux grade 3 scapular notch. Which surgical technique during the initial index procedure would have most effectively decreased the risk of this complication?

. Superior tilt of the glenosphere
. Medialization of the glenosphere without inferior overhang
. Inferior placement of the glenosphere with overhang and lateralization
. Use of the smallest available diameter glenosphere
. Increased retroversion of the humeral component

Correct Answer & Explanation

. Inferior placement of the glenosphere with overhang and lateralization

Explanation

Scapular notching in RTSA is caused by mechanical impingement of the medial edge of the humeral cup against the inferior scapular neck during adduction. Techniques to prevent notching include placing the glenosphere inferiorly (creating an inferior overhang), lateralizing the center of rotation (via bone graft or metallic augmentation), using a larger diameter glenosphere, and placing the glenosphere with an inferior tilt.

Question 1486

Topic: Elbow & Forearm

A 38-year-old male undergoes a single-incision anterior distal biceps tendon repair using a cortical button technique. Postoperatively, he exhibits a complete inability to actively extend his thumb and fingers at the metacarpophalangeal (MP) joints, though his wrist extension is preserved with radial deviation. This complication is most likely due to injury to which structure, and during which surgical step?

. Lateral antebrachial cutaneous nerve during superficial dissection
. Posterior interosseous nerve (PIN) during drilling of the posterior cortex
. Median nerve during retrieval of the retracted tendon
. Radial nerve proper due to prolonged tourniquet ischemia
. Anterior interosseous nerve during deep retractor placement

Correct Answer & Explanation

. Posterior interosseous nerve (PIN) during drilling of the posterior cortex

Explanation

The posterior interosseous nerve (PIN) is at risk during the single-incision distal biceps repair, particularly when drilling the posterior (far) cortex of the radius or passing the cortical button. If the forearm is not fully pronated during this step, the PIN wraps closer to the drill trajectory. Injury results in PIN palsy: loss of finger and thumb MP extension (finger drop), but preserved wrist extension (with radial deviation) because the extensor carpi radialis longus is innervated by the radial nerve proper proximal to the PIN bifurcation.

Question 1487

Topic: 9. Shoulder and Elbow

During an anatomic total shoulder arthroplasty, the surgeon is selecting the appropriate humeral head component. Overstuffing the glenohumeral joint with a humeral head component that is too thick will most likely result in which of the following postoperative issues?

. Increased anterior subluxation and instability
. Diminished active external rotation and excessive tension on the subscapularis repair
. Inferior subluxation of the humeral head mimicking axillary nerve palsy
. Increased risk of posterior glenoid component wear
. Excessive laxity of the rotator interval leading to multidirectional instability

Correct Answer & Explanation

. Diminished active external rotation and excessive tension on the subscapularis repair

Explanation

Overstuffing the joint in anatomic TSA (by using an excessively thick humeral head or placing it too high) tightens the soft tissue envelope excessively. This typically limits the patient's arc of motion, specifically restricting external rotation, and places undue tension on the anterior structures, increasing the risk of postoperative subscapularis repair failure. It also accelerates polyethylene wear due to increased joint reactive forces.

Question 1488

Topic: Shoulder Arthroplasty & Arthritis

A 68-year-old female undergoes a reverse total shoulder arthroplasty (RTSA). Six weeks postoperatively, she presents to the emergency department with an anterior dislocation of the prosthesis. Which of the following is considered the most significant mechanical risk factor for instability following a RTSA?

. Use of a constrained retentive liner
. Primary subscapularis repair at the conclusion of the case
. Inadequate restoration of humeral length and deltoid tension
. Lateralization of the glenosphere using a bony offset
. Excessive retroversion of the glenoid baseplate

Correct Answer & Explanation

. Inadequate restoration of humeral length and deltoid tension

Explanation

The stability of a reverse total shoulder prosthesis is primarily provided by the resting tension and compressive force of the deltoid muscle across the joint. Inadequate restoration of humeral length (failure to sufficiently lengthen the humerus and tension the deltoid) is the most significant mechanical risk factor for dislocation following RTSA.

Question 1489

Topic: 9. Shoulder and Elbow

A 32-year-old male falls on an outstretched hand and sustains an anteromedial facet fracture of the coronoid. What is the primary mechanism of injury causing this specific coronoid fracture pattern, and which ligament is most critically involved?

. Valgus and posterolateral rotatory stress; lateral ulnar collateral ligament (LUCL)
. Varus and posteromedial rotatory stress; lateral collateral ligament (LCL) complex
. Varus and posteromedial rotatory stress; medial collateral ligament (MCL)
. Hyperextension; anterior band of the medial collateral ligament (AMCL)
. Direct axial load in pronation; central band of the interosseous membrane

Correct Answer & Explanation

. Varus and posteromedial rotatory stress; lateral collateral ligament (LCL) complex

Explanation

Anteromedial facet fractures of the coronoid are the hallmark of posteromedial rotatory instability (PMRI) of the elbow. The mechanism typically involves an axial load with varus stress on an extended elbow. The lateral collateral ligament (LCL) complex (specifically the LUCL) invariably fails first, leading to varus subluxation and subsequent impingement/fracture of the anteromedial coronoid facet against the medial trochlea.

Question 1490

Topic: 9. Shoulder and Elbow

A surgeon is considering the use of an unlinked (unconstrained) total elbow arthroplasty for a 65-year-old female with advanced post-traumatic arthritis. Which of the following is an absolute prerequisite for the successful implantation and stability of an unlinked total elbow prosthesis?

. An intact and fully preserved olecranon tip
. Competent medial and lateral collateral ligaments with adequate column bone stock
. Absence of systemic inflammatory arthropathies such as rheumatoid arthritis
. A fully functional and hypertrophied triceps mechanism
. A preoperative elbow flexion arc of greater than 90 degrees

Correct Answer & Explanation

. Competent medial and lateral collateral ligaments with adequate column bone stock

Explanation

Unlinked (unconstrained) total elbow prostheses do not have a mechanical hinge connecting the humeral and ulnar components. Therefore, they rely heavily on the native soft tissue envelope—specifically competent medial and lateral collateral ligaments—and adequate epicondylar and columnar bone stock for stability. If the ligaments are incompetent or the columns are destroyed, a linked (semi-constrained) prosthesis is required to prevent dislocation.

Question 1491

Topic: 9. Shoulder and Elbow

A 58-year-old former gymnast presents with chronic lateral elbow pain, clicking, and a 15-degree extension deficit. Radiographs demonstrate isolated severe radiocapitellar osteoarthritis with a completely preserved, healthy ulnohumeral joint. If nonoperative management fails, what is the most appropriate surgical intervention to relieve pain while preserving elbow kinematics and stability?

. Total elbow arthroplasty (TEA)
. Simple radial head resection without implant replacement
. Radiocapitellar arthroplasty (radial head replacement with or without capitellar resurfacing)
. Ulnohumeral arthrodesis
. Reconstruction of the lateral ulnar collateral ligament

Correct Answer & Explanation

. Radiocapitellar arthroplasty (radial head replacement with or without capitellar resurfacing)

Explanation

For isolated severe radiocapitellar arthritis in a relatively young/active patient with a preserved ulnohumeral joint, radiocapitellar arthroplasty (which includes radial head replacement and potentially capitellar resurfacing) is the most appropriate joint-preserving surgery. Simple radial head resection is associated with proximal migration of the radius, longitudinal forearm instability, and progressive ulnohumeral overload/valgus instability, and is therefore generally avoided in this population unless absolutely indicated.

Question 1492

Topic: 9. Shoulder and Elbow

Which of the following describes the ideal positioning of the glenosphere in a reverse total shoulder arthroplasty to minimize the risk of inferior scapular notching?

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

Correct Answer & Explanation

. Superior translation and inferior tilt

Explanation

Inferior scapular notching is a common complication of reverse total shoulder arthroplasty. Placing the glenosphere with inferior translation (overhanging the inferior glenoid rim) and inferior tilt minimizes impingement of the humeral component on the scapular neck during adduction.

Question 1493

Topic: 9. Shoulder and Elbow

A 68-year-old male with primary glenohumeral osteoarthritis presents with a Walch B2 glenoid. If an anatomic total shoulder arthroplasty is planned, which of the following is the most appropriate management of the glenoid to prevent early component failure?

. Concentric reaming to the level of the neoglenoid
. Eccentric reaming of the anterior glenoid to correct version
. Implantation of a standard pegged glenoid with posterior cement augmentation
. Use of a posteriorly augmented glenoid component or eccentric reaming of the high anterior side
. Placement of the glenoid component in 15 degrees of retroversion

Correct Answer & Explanation

. Use of a posteriorly augmented glenoid component or eccentric reaming of the high anterior side

Explanation

A Walch B2 glenoid is characterized by posterior wear and biconcavity. Management requires correcting the retroversion to within 10 degrees of neutral, typically achieved by eccentric reaming of the anterior, unworn bone or utilizing a posteriorly augmented glenoid component to prevent posterior instability and early loosening.

Question 1494

Topic: 9. Shoulder and Elbow

In a patient undergoing total elbow arthroplasty (TEA) for a comminuted distal humerus fracture, what is the primary biomechanical advantage of incorporating an anterior flange on the humeral component?

. It increases the rotational stability of the component within the humeral canal.
. It resists posterior displacing forces on the humeral component during active elbow extension.
. It prevents anterior subluxation of the ulnar component during elbow flexion.
. It enhances the moment arm of the triceps brachii.
. It eliminates the need for a linked ulnohumeral hinge.

Correct Answer & Explanation

. It resists posterior displacing forces on the humeral component during active elbow extension.

Explanation

The anterior flange of the humeral component in a TEA rests against the anterior humeral cortex. This design effectively resists posterior displacing forces generated during active elbow extension and triceps loading, thereby reducing the risk of posterior component loosening.

Question 1495

Topic: 9. Shoulder and Elbow

A 72-year-old female undergoes an anatomic total shoulder arthroplasty. Six weeks postoperatively, she reports acute onset of anterior shoulder pain and inability to actively internally rotate her arm after a minor fall. Radiographs reveal anterior subluxation of the humeral head. Which of the following is the most likely cause?

. Deltoid dehiscence
. Subscapularis tendon failure
. Glenoid component aseptic loosening
. Excessive retroversion of the humeral component
. Axillary nerve neuropraxia

Correct Answer & Explanation

. Subscapularis tendon failure

Explanation

Subscapularis tendon failure after anatomic TSA typically presents with anterior shoulder pain, weakness in internal rotation, increased passive external rotation, and anterior subluxation of the humeral head. Early diagnosis and repair are critical to restore function and stability.

Question 1496

Topic: 9. Shoulder and Elbow

Which of the following best describes the principle of radial mismatch in anatomic total shoulder arthroplasty?

. The radius of curvature of the glenoid and humeral head are identical to maximize contact area.
. The radius of curvature of the glenoid is slightly larger than the humeral head to allow translation and reduce rim loading.
. The radius of curvature of the humeral head is slightly larger than the glenoid to prevent superior migration.
. A conforming articulation is used to compensate for a deficient rotator cuff.
. Radial mismatch refers to the superior-inferior diameter being larger than the anterior-posterior diameter.

Correct Answer & Explanation

. The radius of curvature of the glenoid is slightly larger than the humeral head to allow translation and reduce rim loading.

Explanation

Radial mismatch means the radius of curvature of the glenoid component is slightly larger than that of the humeral head (typically by 2 to 4 mm). This non-conforming design allows necessary physiologic translation of the humeral head and reduces eccentric rim loading, which protects the glenoid from early loosening.

Question 1497

Topic: Elbow & Forearm

A 55-year-old male with an acute, highly comminuted intra-articular distal humerus fracture is being considered for elbow arthroplasty. Which of the following is an absolute contraindication for a distal humeral hemiarthroplasty?

. Age less than 60 years
. Presence of an intact coronoid and radial head
. Incompetence of the lateral ulnar collateral ligament (LUCL)
. Absence of a reconstructable radial head and coronoid
. Concomitant olecranon fracture

Correct Answer & Explanation

. Absence of a reconstructable radial head and coronoid

Explanation

Distal humeral hemiarthroplasty relies on the native proximal ulna and radius for stability and containment. The absence of an intact or reconstructable radial head and coronoid process is an absolute contraindication because it results in a highly unstable joint.

Question 1498

Topic: 9. Shoulder and Elbow

In reverse total shoulder arthroplasty (RTSA), moving the center of rotation medially and distally achieves which of the following biomechanical effects?

. Decreases the moment arm of the deltoid
. Increases the shear forces across the glenoid baseplate
. Increases the moment arm of the deltoid and converts shear forces to compressive forces at the glenoid
. Restores the anatomic force couple of the native rotator cuff
. Increases reliance on the subscapularis for overhead elevation

Correct Answer & Explanation

. Increases the moment arm of the deltoid and converts shear forces to compressive forces at the glenoid

Explanation

Grammont's reverse shoulder design shifts the center of rotation medially and distally compared to the native shoulder. This increases the deltoid moment arm, improving its mechanical advantage, and converts deforming shear forces into stabilizing compressive forces at the bone-baseplate interface.

Question 1499

Topic: 9. Shoulder and Elbow

A 76-year-old female presents with acute elbow pain and weakness in extension 3 months after a total elbow arthroplasty utilizing a triceps-reflecting approach. Radiographs show no implant loosening. Which of the following physical examination findings is most specific for triceps avulsion?

. Inability to passively extend the elbow
. Loss of active elbow extension against gravity with intact passive extension
. Inability to perform a positive belly-press test
. A palpable gap in the brachioradialis
. Weakness in forearm supination

Correct Answer & Explanation

. Loss of active elbow extension against gravity with intact passive extension

Explanation

Triceps insufficiency or avulsion post-TEA presents with an extension lag or complete loss of active elbow extension against gravity, while passive extension remains intact. A triceps-reflecting approach carries a recognized risk of this complication if the repair fails.

Question 1500

Topic: 9. Shoulder and Elbow

A 68-year-old male with glenohumeral osteoarthritis presents for an anatomic total shoulder arthroplasty. Preoperative CT scan demonstrates a Walch B2 glenoid with 20 degrees of retroversion. What is the most appropriate surgical strategy for managing the glenoid to minimize the risk of early component loosening?

. High-side eccentric anterior reaming to neutral version
. Standard concentric reaming and placement of a keeled non-augmented component
. Use of a posteriorly augmented glenoid component or posterior bone grafting
. Implantation of a hemiarthroplasty instead of a total shoulder
. Anterior closing wedge osteotomy of the glenoid vault

Correct Answer & Explanation

. Use of a posteriorly augmented glenoid component or posterior bone grafting

Explanation

Walch B2 glenoids feature biconcave wear and posterior subluxation. Uncorrected retroversion (>15 degrees) leads to high failure rates; augmented components or bone grafting are preferred over excessive eccentric reaming, which dangerously compromises the subchondral bone.

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