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9. Shoulder and Elbow MCQs

Practice Set 164 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 3261

Topic: Elbow & Forearm
A 40-year-old recreational tennis player has recalcitrant lateral epicondylitis (tennis elbow) that has failed 6 months of physical therapy, bracing, and NSAIDs. He elects to undergo a platelet-rich plasma (PRP) injection. Based on current basic science and clinical evidence, which PRP formulation is most effective for tendinopathy such as lateral epicondylitis?
. Leukocyte-poor PRP (LP-PRP)
. Leukocyte-rich PRP (LR-PRP)
. Platelet-poor plasma (PPP)
. Bone marrow aspirate concentrate (BMAC)
. Acellular dermal matrix solution

Correct Answer & Explanation

. Leukocyte-rich PRP (LR-PRP)

Explanation

Current evidence suggests that Leukocyte-Rich PRP (LR-PRP) is more effective for tendinopathies (such as lateral epicondylitis and patellar tendinopathy) due to the robust inflammatory response it induces, which helps restart the healing cascade in chronic tendinosis. Conversely, Leukocyte-Poor PRP (LP-PRP) is generally preferred for intra-articular injections (like knee osteoarthritis) to minimize an excessive inflammatory response and synoviocyte apoptosis.

Question 3262

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female presents with chronic shoulder pain and an inability to actively elevate her arm above 40 degrees. On examination, she has a positive hornblower's sign but her deltoid function is intact. Radiographs demonstrate superior migration of the humeral head and acetabularization of the coracoacromial arch (Hamada grade 3). Which of the following is the most reliable surgical option?

. Arthroscopic massive rotator cuff repair
. Hemiarthroplasty
. Anatomic total shoulder arthroplasty
. Reverse total shoulder arthroplasty
. Latissimus dorsi tendon transfer

Correct Answer & Explanation

. Arthroscopic massive rotator cuff repair

Explanation

Reverse total shoulder arthroplasty (RTSA) is indicated for older patients with rotator cuff tear arthropathy and pseudoparalysis. It relies on the intact deltoid to elevate the arm by medializing and distalizing the center of rotation, which optimizes the deltoid's moment arm.

Question 3263

Topic: Elbow & Forearm

In the surgical management of a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, and coronoid fracture), what is the most accepted sequential order of structure repair to restore stability?

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

Correct Answer & Explanation

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

Explanation

The standard surgical algorithm for a terrible triad is performed deep-to-superficial: coronoid fracture fixation or anterior capsular repair is performed first, followed by radial head fixation or arthroplasty, and finally the lateral ulnar collateral ligament (LUCL) complex is repaired.

Question 3264

Topic: Elbow & Forearm

Posterolateral rotatory instability (PLRI) of the elbow is a clinical entity most frequently caused by insufficiency of which of the following capsuloligamentous structures?

. Medial ulnar collateral ligament
. Lateral ulnar collateral ligament (LUCL)
. Radial collateral ligament
. Annular ligament
. Anterior capsule

Correct Answer & Explanation

. Medial ulnar collateral ligament

Explanation

The Lateral Ulnar Collateral Ligament (LUCL) is the primary restraint to posterolateral rotatory instability (PLRI) of the elbow. Injury to the LUCL allows the radial head to subluxate posterolaterally away from the capitellum.

Question 3265

Topic: Elbow & Forearm

A 45-year-old male undergoes a single-incision anterior approach for the repair of a distal biceps tendon rupture. Post-operatively, he complains of numbness over the lateral aspect of his forearm. Which nerve is most likely injured during this surgical exposure?

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

Correct Answer & Explanation

. Posterior interosseous nerve (PIN)

Explanation

The lateral antebrachial cutaneous (LABC) nerve is the most commonly injured nerve during a single-incision anterior approach to the distal biceps. The posterior interosseous nerve (PIN) is more at risk during a two-incision approach or with excessive deep retractor placement.

Question 3266

Topic: 9. Shoulder and Elbow
A 5-year-old boy falls on an outstretched hand. Elbow radiographs reveal an ossific density within the medial aspect of the elbow joint space. The normal medial epicondyle ossification center is absent. To avoid misdiagnosing this incarcerated fragment as a normal developing ossification center, which ossification center's chronological appearance must be verified absent according to normal pediatric development?
. Capitellum
. Radial head
. Trochlea
. Lateral epicondyle
. Olecranon

Correct Answer & Explanation

. Trochlea

Explanation

The correct order of elbow ossification is CRITOE. The medial (Internal) epicondyle normally appears around age 4-6. The Trochlea appears later (age 7-9). If an ossific density is seen in the medial joint of a 5-year-old, it cannot be the trochlea; it is an incarcerated medial epicondyle.

Question 3267

Topic: Shoulder Pathology

A 25-year-old patient presents with right shoulder pain and weakness when lifting objects above his head. Examination reveals medial scapular winging that worsens when the patient pushes against a wall. Injury to which of the following nerves is the most likely cause?

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

Correct Answer & Explanation

. Spinal accessory nerve

Explanation

Medial scapular winging is classically caused by paralysis of the serratus anterior muscle, which is innervated by the long thoracic nerve. Lateral winging is characteristic of trapezius paralysis due to spinal accessory nerve injury.

Question 3268

Topic: 9. Shoulder and Elbow

In the surgical reconstruction of the medial ulnar collateral ligament (UCL) of the elbow in throwing athletes, the graft is primarily positioned to replicate the biomechanical function of which specific structural component?

. Posterior bundle of the UCL
. Transverse ligament of the UCL
. Anterior band of the anterior bundle of the UCL
. Posterior band of the anterior bundle of the UCL
. Radial collateral ligament

Correct Answer & Explanation

. Posterior bundle of the UCL

Explanation

The anterior bundle of the UCL is the primary restraint to valgus stress. Specifically, the anterior band of the anterior bundle is taut in extension and the primary restraint up to 90 degrees of flexion, making it the primary target for anatomical reproduction during Tommy John surgery.

Question 3269

Topic: 9. Shoulder and Elbow

A 55-year-old female with Type I diabetes mellitus presents with progressive, severe restriction of both active and passive shoulder motion. She is diagnosed with primary adhesive capsulitis. Which cytokine is most strongly implicated in driving the excessive capsular fibroblastic proliferation seen in this condition?

. Interleukin-1 (IL-1)
. Tumor necrosis factor-alpha (TNF-a)
. Transforming growth factor-beta (TGF-b)
. Interleukin-6 (IL-6)
. Interleukin-10 (IL-10)

Correct Answer & Explanation

. Interleukin-1 (IL-1)

Explanation

Transforming growth factor-beta (TGF-b) and platelet-derived growth factor (PDGF) are the primary cytokines implicated in the pathogenesis of adhesive capsulitis, promoting excessive fibroblastic proliferation and subsequent capsular fibrosis.

Question 3270

Topic: 9. Shoulder and Elbow

During a Reverse Total Shoulder Arthroplasty (RTSA), superior or posterior retractor placement and aberrant screw placement in the superior or posterior glenoid vault can most likely cause iatrogenic injury to which of the following nerves?

. Axillary nerve
. Suprascapular nerve
. Musculocutaneous nerve
. Radial nerve
. Long thoracic nerve

Correct Answer & Explanation

. Axillary nerve

Explanation

The suprascapular nerve courses intimately along the posterior aspect of the glenoid neck (from the suprascapular notch to the spinoglenoid notch). It is highly vulnerable to injury from over-penetrating posterior or superior glenoid baseplate screws and aggressive posterior retraction.

Question 3271

Topic: 9. Shoulder and Elbow

A 12-year-old Little League pitcher presents with medial elbow pain. Radiographs demonstrate widening of the medial epicondyle apophysis without displacement. What is the most common underlying pathomechanical force responsible for this condition (Little Leaguer's elbow)?

. Varus overload during the late cocking phase
. Valgus overload during the late cocking phase
. Direct posterior impingement in the follow-through phase
. Axial compression during the acceleration phase
. Torsional stress during the wind-up phase

Correct Answer & Explanation

. Varus overload during the late cocking phase

Explanation

Medial epicondyle apophysitis (Little Leaguer's elbow) in overhead throwing athletes is caused by repetitive valgus overload during the late cocking and early acceleration phases of throwing. This places enormous tensile stress on the developing medial structures.

Question 3272

Topic: 9. Shoulder and Elbow

Which of the following best describes the biomechanical advantage of shifting the center of rotation medially and distally in a reverse total shoulder arthroplasty (rTSA)?

. It decreases the moment arm of the deltoid, allowing for faster muscle rehabilitation.
. It increases deltoid tension and its moment arm, enhancing active elevation.
. It increases the shear force at the glenoid baseplate, improving bony ingrowth.
. It restores the original anatomical center of rotation of the native glenohumeral joint.
. It decreases inferior impingement but substantially reduces the tension of the remaining rotator cuff.

Correct Answer & Explanation

. It decreases the moment arm of the deltoid, allowing for faster muscle rehabilitation.

Explanation

In a reverse total shoulder arthroplasty, the center of rotation is shifted medially and distally compared to the native shoulder. This biomechanical alteration increases the deltoid moment arm and tension, recruiting more anterior and posterior deltoid fibers for elevation and abduction, compensating for the lack of a functional rotator cuff.

Question 3273

Topic: 9. Shoulder and Elbow

A 35-year-old male sustains a fracture involving the anteromedial facet of the coronoid process after a fall on an outstretched hand. If this fracture is not properly stabilized, the elbow is at highest risk for developing which specific pattern of instability?

. Valgus posterolateral rotatory instability
. Varus posteromedial rotatory instability
. Pure posterior elbow dislocation
. Proximal radioulnar joint dissociation
. Isolated anterior radiocapitellar instability

Correct Answer & Explanation

. Valgus posterolateral rotatory instability

Explanation

Fractures of the anteromedial facet of the coronoid (O'Driscoll Subtype 2) compromise the insertion of the anterior bundle of the MCL and the medial bony buttress of the ulna. If left untreated, this typically leads to varus posteromedial rotatory instability (VPMRI) of the elbow, often accompanied by LCL disruption.

Question 3274

Topic: Elbow & Forearm

What is the most widely accepted surgical sequence for repairing a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, and coronoid fracture)?

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

Correct Answer & Explanation

. LCL complex repair, radial head fixation/replacement, coronoid fixation

Explanation

The standard algorithm for repairing a terrible triad injury follows a deep-to-superficial and medial-to-lateral protocol through a lateral approach: first, fixation of the coronoid (to restore the anterior buttress); second, fixation or replacement of the radial head (to restore the lateral column); and third, repair of the lateral collateral ligament (LCL) complex to the lateral epicondyle.

Question 3275

Topic: Shoulder Pathology

A lower trapezius tendon transfer is performed for a patient with a massive, irreparable posterosuperior rotator cuff tear to restore active external rotation. What is the primary motor innervation to the transferred muscle?

. Spinal accessory nerve
. Dorsal scapular nerve
. Thoracodorsal nerve
. Suprascapular nerve
. Axillary nerve

Correct Answer & Explanation

. Spinal accessory nerve

Explanation

The trapezius muscle, including its lower fibers utilized in this tendon transfer, is innervated by the spinal accessory nerve (Cranial Nerve XI). This is critical knowledge during harvest and mobilization to avoid denervating the transfer.

Question 3276

Topic: 9. Shoulder and Elbow

A 24-year-old trauma patient presents with scapulothoracic dissociation characterized by massive lateral displacement of the scapula on the AP chest radiograph. Due to the high mortality and morbidity associated with this injury, which of the following must be evaluated emergently?

. CT myelogram to assess for C5-C6 nerve root avulsion
. Immediate operative exploration of the brachial plexus
. Emergent upper extremity angiography or CT angiography
. Closed reduction of the sternoclavicular joint
. Application of a shoulder spica cast to stabilize the shoulder girdle

Correct Answer & Explanation

. CT myelogram to assess for C5-C6 nerve root avulsion

Explanation

Scapulothoracic dissociation is a high-energy injury often described as a 'closed forequarter amputation'. It is associated with severe neurovascular trauma. Subclavian or axillary artery disruption is highly prevalent and life-threatening; therefore, emergent vascular assessment (angiography/CTA) is the most critical immediate step.

Question 3277

Topic: Elbow & Forearm

The distal biceps tendon normally inserts onto the radial tuberosity. To maximize the biomechanical supination moment arm (the 'cam effect') during an anatomical surgical repair of a distal biceps rupture, where should the tendon be optimally positioned on the tuberosity?

. On the extreme anterior/volar aspect of the tuberosity.
. Centrally within the tuberosity footprint.
. On the ulnar/posterior aspect of the tuberosity.
. On the extreme distal margin of the tuberosity.
. On the lateral aspect of the tuberosity.

Correct Answer & Explanation

. On the extreme anterior/volar aspect of the tuberosity.

Explanation

The native distal biceps tendon inserts on the ulnar (posterior) aspect of the radial tuberosity. Reattaching the tendon to this ulnar footprint maximizes the 'cam effect' around the radius, thereby restoring maximal supination torque. A more anterior placement results in a significant loss of supination strength.

Question 3278

Topic: 9. Shoulder and Elbow

In a patient presenting with primary adhesive capsulitis (frozen shoulder), the classic physical examination finding is marked restriction of passive external rotation with the arm adducted at the side. This specific restriction is most anatomically attributed to contracture of which of the following structures?

. Posterior band of the inferior glenohumeral ligament
. Middle glenohumeral ligament
. Coracohumeral ligament and the rotator interval
. Posterior capsule
. Superior labrum and biceps anchor

Correct Answer & Explanation

. Posterior band of the inferior glenohumeral ligament

Explanation

Loss of external rotation with the arm resting at the side (0 degrees of abduction) is the hallmark of adhesive capsulitis. This specific motion restriction is predominantly caused by contracture and fibroplasia of the rotator interval and the coracohumeral ligament (CHL).

Question 3279

Topic: Shoulder Arthroplasty & Arthritis

A 70-year-old female undergoes a reverse total shoulder arthroplasty (RTSA) for rotator cuff tear arthropathy. To minimize the risk of inferior scapular notching, which is a common complication, how should the glenosphere baseplate optimally be positioned?

. Superiorly translated and superiorly tilted
. Superiorly translated and inferiorly tilted
. Inferiorly translated and inferiorly tilted
. Inferiorly translated and superiorly tilted
. Centered exactly in the middle of the glenoid without any tilt

Correct Answer & Explanation

. Superiorly translated and superiorly tilted

Explanation

Scapular notching occurs when the humeral component impinges on the inferior scapular neck during adduction. The risk is significantly minimized by positioning the glenosphere with inferior translation (so it overhangs the inferior glenoid rim by 2-4 mm) and placing it with an inferior tilt.

Question 3280

Topic: Elbow & Forearm

In posterolateral rotatory instability (PLRI) of the elbow, the primary deficient structure is the lateral ulnar collateral ligament (LUCL). What are the precise anatomic origin and insertion of the LUCL?

. Lateral epicondyle to the radial neck
. Lateral epicondyle to the supinator crest of the ulna
. Capitellum to the sublime tubercle
. Lateral epicondyle to the coronoid process
. Radial collateral ligament to the annular ligament

Correct Answer & Explanation

. Lateral epicondyle to the radial neck

Explanation

The LUCL originates on the lateral epicondyle, blends with the annular ligament, and inserts on the supinator crest of the proximal ulna. It serves as the primary restraint to posterolateral rotatory instability.

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