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9. Shoulder and Elbow MCQs

Practice Set 117 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 2321

Topic: Elbow & Forearm

A 45-year-old man undergoes repair of an acute distal biceps tendon rupture via a single-incision anterior approach.

Postoperatively, he notes a patch of numbness on the radial aspect of his forearm. Which nerve was most likely injured or stretched during the surgical exposure?

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

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve (LABCN)

Explanation

The lateral antebrachial cutaneous nerve (LABCN) is the most commonly injured nerve during a single-incision anterior approach for distal biceps repair. It runs in the subcutaneous tissue near the cephalic vein in the lateral aspect of the antecubital fossa and is highly vulnerable during superficial dissection and retraction. While the PIN is at risk during deep retractor placement radially or in a two-incision approach, the LABCN is overall the most frequently affected.

Question 2322

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old woman with advanced cuff tear arthropathy and pseudoparalysis undergoes a reverse total shoulder arthroplasty (RTSA).

To minimize the risk of inferior scapular notching postoperatively, how should the glenoid baseplate and glenosphere be positioned?

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

Correct Answer & Explanation

. Superior translation and superior tilt

Explanation

Scapular notching is a frequent complication of RTSA resulting from the medial and inferior aspect of the humeral tray impinging against the scapular neck during adduction. The widely accepted technique to minimize this mechanical conflict is positioning the glenoid baseplate with an inferior tilt and inferior translation, allowing the glenosphere to overhang the inferior rim of the native glenoid.

Question 2323

Topic: 9. Shoulder and Elbow

A 45-year-old man sustains a terrible triad injury to his left elbow after falling from a ladder. He undergoes operative management including radial head replacement, lateral collateral ligament (LCL) repair, and coronoid fracture fixation. Postoperatively, he is engaged in a supervised rehabilitation protocol. What is the most common complication this patient is likely to experience following surgical management of this injury?

. Recurrent posterolateral rotatory instability
. Proximal radioulnar synostosis
. Ulnar neuropathy
. Loss of terminal elbow extension
. Nonunion of the coronoid process

Correct Answer & Explanation

. Recurrent posterolateral rotatory instability

Explanation

The most common complication following operative management of a terrible triad injury (elbow dislocation, radial head fracture, and coronoid fracture) is elbow stiffness, specifically a loss of terminal extension. While recurrent instability, heterotopic ossification, and ulnar neuropathy can occur, some degree of extension loss is nearly universal, with studies showing an average loss of 10 to 15 degrees of terminal extension even with optimal surgical fixation and early rehabilitation.

Question 2324

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old woman with a massive, irreparable rotator cuff tear and pseudoparalysis is scheduled to undergo a reverse total shoulder arthroplasty (RTSA). Scapular notching is a well-documented complication of this procedure. Which of the following surgical modifications or implant design choices is most effective in decreasing the incidence of scapular notching?

. Superior translation of the glenosphere
. Inferior translation of the glenosphere past the inferior glenoid rim
. Decreasing the diameter of the glenosphere
. Increasing the neck-shaft angle of the humeral component to 155 degrees
. Medialization of the center of rotation without inferior translation

Correct Answer & Explanation

. Superior translation of the glenosphere

Explanation

Scapular notching occurs when the humeral component impinges against the inferior neck of the scapula during adduction. Placing the glenosphere with an inferior translation (overhanging the inferior glenoid rim by 2 to 4 mm) limits this mechanical impingement. Additionally, lateralization of the glenosphere, a smaller neck-shaft angle (e.g., 135 vs 155 degrees), and a larger glenosphere diameter have also been shown to reduce the risk of scapular notching.

Question 2325

Topic: Shoulder Arthroplasty & Arthritis

Scapular notching is a well-recognized complication following reverse total shoulder arthroplasty (RTSA). Which of the following technical adjustments regarding glenosphere positioning most effectively minimizes the risk of inferior scapular notching?

. Superior placement with a superior tilt
. Inferior placement with an inferior tilt
. Central placement with a superior tilt
. Superior placement with neutral tilt
. Medialized placement with superior tilt

Correct Answer & Explanation

. Superior placement with a superior tilt

Explanation

Scapular notching in RTSA occurs when the medial aspect of the humeral tray or liner impinges against the inferior scapular neck during arm adduction. To minimize this, biomechanical and clinical studies have shown that placing the glenosphere low on the glenoid (inferior placement) with an inferior tilt (typically 0 to 10 degrees) increases the impingement-free range of motion. Lateralization of the center of rotation also decreases notching, whereas medialization and superior placement increase the risk of impingement and subsequent notching.

Question 2326

Topic: 9. Shoulder and Elbow

A 42-year-old woman sustains a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, and coronoid fracture).

Following an initial closed reduction in the emergency department, the elbow remains persistently unstable in extension. During operative management, what is the generally recommended sequence of reconstruction to restore elbow stability?

. Lateral collateral ligament (LCL) repair, followed by radial head fixation, then coronoid fixation
. Coronoid fixation, followed by radial head fixation or replacement, then LCL repair
. Radial head fixation, followed by coronoid fixation, then medial collateral ligament (MCL) repair
. MCL repair, followed by coronoid fixation, then radial head fixation
. LCL repair, followed by MCL repair, then coronoid fixation

Correct Answer & Explanation

. Lateral collateral ligament (LCL) repair, followed by radial head fixation, then coronoid fixation

Explanation

The standard surgical protocol for a terrible triad injury of the elbow progresses from deep to superficial and from inside to outside. The generally accepted sequence is: 1) Fixation of the coronoid process (or repair of the anterior capsule to the coronoid base) to restore the anterior buttress; 2) Repair or replacement of the radial head; 3) Repair of the lateral collateral ligament (LCL) complex to the lateral epicondyle. If the elbow remains unstable after these three steps, the MCL may be repaired, or a hinged external fixator may be applied.

Question 2327

Topic: Elbow & Forearm

A 38-year-old male weightlifter undergoes surgical repair of a complete distal biceps tendon rupture via a single-incision anterior approach. Postoperatively, he complains of numbness and tingling over the anterolateral aspect of his forearm. Motor function of the hand and wrist is completely intact. Which nerve is most likely injured, and what is its anatomic relationship to the biceps tendon?

. Posterior interosseous nerve; it crosses anterior to the radial neck
. Lateral antebrachial cutaneous nerve; it emerges lateral to the biceps tendon between the biceps and brachialis
. Superficial radial nerve; it runs deep to the brachioradialis
. Medial antebrachial cutaneous nerve; it runs medial to the brachial artery
. Anterior interosseous nerve; it branches from the median nerve in the proximal forearm

Correct Answer & Explanation

. Posterior interosseous nerve; it crosses anterior to the radial neck

Explanation

The lateral antebrachial cutaneous nerve (LABCN), which is the terminal sensory branch of the musculocutaneous nerve, is the most commonly injured nerve during a single-incision anterior approach for distal biceps repair. It emerges from beneath the lateral edge of the biceps muscle, passing between the biceps and brachialis, making it highly vulnerable during retraction. The posterior interosseous nerve (PIN) is more commonly injured during a two-incision approach or if retractors are placed blindly around the radial neck.

Question 2328

Topic: 9. Shoulder and Elbow

A 74-year-old right-hand-dominant woman sustains a closed 4-part proximal humerus fracture after a mechanical fall. Her medical history is notable for severe glenohumeral osteoarthritis and a known massive, irreparable rotator cuff tear with preoperative pseudoparalysis. What is the most appropriate surgical management?

. Open reduction and internal fixation with a locking plate
. Hemiarthroplasty
. Anatomic total shoulder arthroplasty
. Reverse total shoulder arthroplasty
. Closed reduction and percutaneous pinning

Correct Answer & Explanation

. Open reduction and internal fixation with a locking plate

Explanation

In an elderly patient with a 4-part proximal humerus fracture and a history of rotator cuff tear arthropathy (indicated by severe osteoarthritis and pseudoparalysis), reverse total shoulder arthroplasty (rTSA) is the treatment of choice. Hemiarthroplasty and anatomic total shoulder arthroplasty rely on functional tuberosity healing and an intact, functioning rotator cuff for good outcomes, which this patient lacks. ORIF has a high failure rate in osteoporotic bone with 4-part fractures and does not address the preexisting symptomatic arthritis and cuff deficiency.

Question 2329

Topic: Elbow & Forearm

A 35-year-old man falls from a height and sustains a 'terrible triad' injury of the elbow. During surgical reconstruction, the surgeon successfully fixes the coronoid fracture and replaces the highly comminuted radial head. However, the elbow remains persistently unstable in extension and supination. Which of the following is the most critical next step to restore stability?

. Application of a hinged external fixator
. Anterior capsule reconstruction
. Repair of the lateral ulnar collateral ligament (LUCL) to the lateral epicondyle
. Repair of the medial ulnar collateral ligament (MUCL)
. Fascia lata allograft reconstruction of the annular ligament

Correct Answer & Explanation

. Application of a hinged external fixator

Explanation

The terrible triad of the elbow consists of an elbow dislocation, a radial head fracture, and a coronoid fracture. The standard surgical sequence involves addressing the coronoid, fixing or replacing the radial head, and repairing the lateral collateral ligament (LCL) complex—specifically the lateral ulnar collateral ligament (LUCL)—to its isometric origin on the lateral epicondyle. The LUCL is the primary restraint to posterolateral rotatory instability and is virtually always torn in this injury mechanism. Repairing the MUCL or applying an external fixator is generally reserved for residual instability after the LUCL has been properly repaired.

Question 2330

Topic: Elbow & Forearm

A 42-year-old bodybuilder undergoes a single-incision anterior approach for the repair of a complete acute distal biceps tendon rupture. In the recovery room, he complains of numbness and tingling along the lateral (radial) border of his forearm. Motor function is fully intact. Which nerve was most likely injured or compressed by retractors during the surgical exposure?

. Posterior interosseous nerve (PIN)
. Superficial branch of the radial nerve
. Medial antebrachial cutaneous nerve
. Anterior interosseous nerve (AIN)
. Lateral antebrachial cutaneous nerve (LABCN)

Correct Answer & Explanation

. Posterior interosseous nerve (PIN)

Explanation

The lateral antebrachial cutaneous nerve (LABCN) is the terminal sensory branch of the musculocutaneous nerve. It exits the deep fascia lateral to the biceps tendon and is the most commonly injured nerve during a single-incision anterior approach for distal biceps repair due to retraction or direct trauma. Injury results in paresthesias or numbness along the lateral aspect of the forearm. While the posterior interosseous nerve (PIN) is the most dreaded motor nerve injury (causing weak finger/thumb extension), the patient's intact motor function and specific sensory distribution point to the LABCN.

Question 2331

Topic: 9. Shoulder and Elbow

A 68-year-old man presents with anterior shoulder pain and subjective weakness 6 weeks after undergoing an anatomic total shoulder arthroplasty (TSA) via a standard deltopectoral approach. On physical examination, he demonstrates significantly increased passive external rotation compared to the contralateral normal shoulder and a positive belly-press test. Anteroposterior and axillary radiographs demonstrate a well-fixed, appropriately positioned glenoid and humeral implant without loosening or dislocation. What is the most likely diagnosis?

. Subscapularis tendon rupture
. Anterior component subluxation
. Deltoid dehiscence
. Glenoid component loosening
. Axillary nerve palsy

Correct Answer & Explanation

. Subscapularis tendon rupture

Explanation

Subscapularis failure is a known complication after anatomic total shoulder arthroplasty using a deltopectoral approach, where the tendon is typically taken down and repaired. Clinical signs include an unexpected increase in passive external rotation (loss of the anterior tether), internal rotation weakness, and positive specialized tests such as the belly-press, lift-off, or bear-hug tests. Axillary nerve palsy would typically present with deltoid weakness and sensory changes laterally, not isolated internal rotation weakness with increased external rotation.

Question 2332

Topic: 9. Shoulder and Elbow

A 42-year-old man sustains a fall from a ladder, resulting in a terrible triad injury of the right elbow. Intraoperatively, following secure fixation of the coronoid process fracture, a metallic radial head arthroplasty, and robust repair of the lateral collateral ligament (LCL) complex, the elbow is taken through a range of motion. On fluoroscopic examination, the ulnohumeral joint remains persistently subluxated posteriorly when extended beyond 30 degrees. What is the most appropriate next step in surgical management?

. Apply a hinged elbow external fixator
. Repair the medial collateral ligament (MCL)
. Revise the radial head to a larger, oversized component
. Immobilize the elbow in 90 degrees of flexion and full pronation for 4 weeks
. Perform a corrective olecranon osteotomy

Correct Answer & Explanation

. Apply a hinged elbow external fixator

Explanation

The standard surgical algorithm for terrible triad injuries involves repairing deep to superficial, typically starting with coronoid fixation, followed by radial head replacement or repair, and then LCL repair. If the elbow remains persistently unstable (e.g., subluxates in extension) after these three elements have been addressed, the next step in the algorithm is to explore and repair the medial collateral ligament (MCL). A hinged external fixator is reserved for residual instability after the MCL has been repaired or if the MCL repair is inadequate.

Question 2333

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old woman with a history of a massive, irreparable rotator cuff tear and pseudoparalysis undergoes a reverse total shoulder arthroplasty (RTSA). Biomechanically, how does the RTSA restore active forward elevation in the setting of a deficient rotator cuff?

. It lateralizes the center of rotation and decreases the deltoid moment arm.
. It medializes and distalizes the center of rotation, thereby increasing the deltoid moment arm.
. It superiorly shifts the center of rotation to recruit the intact subscapularis.
. It increases tension on the coracoacromial ligament to provide a static restraint.
. It medializes the humerus and proximalizes the center of rotation.

Correct Answer & Explanation

. It lateralizes the center of rotation and decreases the deltoid moment arm.

Explanation

The reverse total shoulder arthroplasty (RTSA) functions by altering the biomechanics of the shoulder. Grammont's original design medializes and distalizes the center of rotation relative to the native shoulder. Medialization recruits more deltoid muscle fibers for elevation, while distalization tensions the deltoid, increasing its resting tone and effectively lengthening its moment arm, which compensates for the absent rotator cuff.

Question 2334

Topic: 9. Shoulder and Elbow

During the surgical management of a 'terrible triad' injury of the elbow, the surgeon fixes the coronoid fracture, replaces the comminuted radial head, and repairs the lateral ulnar collateral ligament (LUCL) to the lateral epicondyle. Upon intraoperative testing, the elbow demonstrates persistent instability and subluxates during extension past 30 degrees. What is the next most appropriate step in management?

. Apply a hinged elbow external fixator
. Perform an open repair of the medial ulnar collateral ligament (MUCL)
. Immobilize the elbow in 90 degrees of flexion and pronation for 6 weeks
. Revise the radial head arthroplasty with a larger implant
. Perform a coronoid reconstruction using an iliac crest bone graft

Correct Answer & Explanation

. Apply a hinged elbow external fixator

Explanation

The classic treatment protocol for terrible triad elbow injuries (elbow dislocation, radial head fracture, coronoid fracture) involves sequentially restoring the stabilizers from deep to superficial: coronoid fixation, radial head fixation or replacement, and LUCL repair. If the elbow remains unstable following these steps, the medial ulnar collateral ligament (MUCL) should be evaluated and repaired. If instability persists even after MUCL repair, a hinged external fixator or cross-pinning is indicated.

Question 2335

Topic: Shoulder Arthroplasty & Arthritis

A 76-year-old woman with a history of severe osteoporosis sustains a 4-part proximal humerus fracture after a mechanical fall. Radiographs demonstrate severe comminution of the tuberosities and a valgus-impacted head with varus collapse. She is functionally active and desires to return to her previous daily activities. Which surgical intervention is associated with the most predictable restoration of active forward elevation in this patient profile?

. Open reduction and internal fixation with a locking plate
. Hemiarthroplasty of the shoulder
. Reverse total shoulder arthroplasty (RTSA)
. Closed reduction and percutaneous pinning
. Intramedullary nailing

Correct Answer & Explanation

. Open reduction and internal fixation with a locking plate

Explanation

Reverse total shoulder arthroplasty (RTSA) has become the preferred surgical treatment for displaced 3- and 4-part proximal humerus fractures in elderly patients with poor bone quality. Compared to hemiarthroplasty and ORIF, RTSA provides more predictable pain relief and restoration of active forward elevation because its function relies on the deltoid muscle rather than anatomic tuberosity healing. Hemiarthroplasty outcomes are notoriously unreliable in this population due to the high rate of tuberosity nonunion or resorption in osteoporotic bone.

Question 2336

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old man underwent a reverse total shoulder arthroplasty (RTSA) for massive rotator cuff tear arthropathy 2 years ago. He now complains of progressive lateral shoulder pain and a 'clunking' sensation. Radiographs demonstrate severe scapular notching that extends beyond the inferior screw of the baseplate. What is the primary modifiable surgical risk factor for scapular notching in RTSA?

. Superior placement of the glenosphere
. Use of a lateralized glenosphere
. Inferior tilt of the glenosphere
. Anterior placement of the glenosphere
. Use of a smaller diameter humeral cup

Correct Answer & Explanation

. Superior placement of the glenosphere

Explanation

Scapular notching in reverse total shoulder arthroplasty (RTSA) is caused by mechanical impingement of the medial edge of the humeral cup against the inferior scapular neck during adduction. The most significant surgeon-controlled risk factor for notching is a superiorly placed glenosphere. To minimize notching, the baseplate and glenosphere should be placed inferiorly on the glenoid, often flush with or slightly overhanging the inferior rim, and with a slight inferior tilt. Lateralizing the center of rotation also helps to decrease scapular notching by increasing the clearance between the humerus and the scapular neck.

Question 2337

Topic: 9. Shoulder and Elbow

A 78-year-old woman with a history of severe rheumatoid arthritis and osteoporosis sustains a 4-part proximal humerus fracture with head-splitting extension after a fall. Radiographs demonstrate significant displacement of the tuberosities and advanced glenohumeral joint space narrowing. Which of the following treatments provides the most reliable outcome for pain relief and functional restoration?

. Nonoperative management with a sling
. Open reduction and internal fixation with a locking plate
. Humeral head hemiarthroplasty
. Reverse total shoulder arthroplasty
. Total shoulder arthroplasty

Correct Answer & Explanation

. Nonoperative management with a sling

Explanation

In an elderly patient with poor bone quality, pre-existing glenohumeral arthritis, and a complex 4-part/head-split fracture, Reverse Total Shoulder Arthroplasty (RTSA) is the most reliable option. Hemiarthroplasty outcomes are heavily dependent on tuberosity healing, which is unpredictable in osteoporotic bone. Total shoulder arthroplasty is contraindicated due to rotator cuff dysfunction associated with 4-part displaced fractures.

Question 2338

Topic: Elbow & Forearm

A 45-year-old man sustains a fall on an outstretched hand, resulting in a 'terrible triad' injury of the elbow. Intraoperatively, the coronoid is found to have a small tip fracture, which is treated with anterior capsular repair. A radial head arthroplasty is performed for a comminuted radial head fracture. Following these steps, the elbow remains persistently unstable in extension and supinates when extended. Which of the following is the most appropriate next step in management?

. Repair of the medial ulnar collateral ligament (MUCL)
. Application of a hinged external fixator
. Repair of the lateral ulnar collateral ligament (LUCL)
. Open reduction and internal fixation of the coronoid process
. Transarticular pinning of the ulnohumeral joint

Correct Answer & Explanation

. Repair of the medial ulnar collateral ligament (MUCL)

Explanation

The standard surgical algorithm for a terrible triad injury involves restoring the anterior column (coronoid), the lateral column (radial head), and the lateral stabilizing structures (LCL complex, specifically the LUCL). If the elbow remains unstable after addressing the coronoid and radial head, the LUCL must be repaired. MUCL repair or hinged external fixation is generally reserved for cases where the elbow remains unstable despite a secure LUCL repair.

Question 2339

Topic: Elbow & Forearm

A 45-year-old man sustains a fall from a height and presents with a 'terrible triad' injury of the elbow. Which of the following correctly describes the typical deep surgical sequence for operative repair of this injury?

. Lateral collateral ligament repair, coronoid fixation, radial head fixation/replacement
. Coronoid fixation, radial head fixation/replacement, lateral collateral ligament repair
. Radial head fixation/replacement, coronoid fixation, lateral collateral ligament repair
. Medial collateral ligament repair, coronoid fixation, radial head fixation/replacement
. Radial head fixation/replacement, lateral collateral ligament repair, coronoid fixation

Correct Answer & Explanation

. Lateral collateral ligament repair, coronoid fixation, radial head fixation/replacement

Explanation

The terrible triad of the elbow consists of an elbow dislocation, a radial head fracture, and a coronoid fracture. The standard 'inside-out' protocol for surgical management involves: 1) repairing or fixing the coronoid fracture to restore the anterior buttress, 2) fixing or replacing the radial head to restore the anterior and valgus buttress, and 3) repairing the lateral ulnar collateral ligament (LUCL) to restore posterolateral rotatory stability. The medial collateral ligament is only addressed if profound instability persists after the standard sequence.

Question 2340

Topic: Elbow & Forearm

A 35-year-old bodybuilder undergoes a two-incision (modified Boyd-Anderson) repair of a distal biceps tendon rupture. Compared to a single anterior incision approach, he is at an increased risk for which of the following complications?

. Lateral antebrachial cutaneous nerve palsy
. Radial nerve palsy
. Heterotopic ossification
. Posterior interosseous nerve palsy
. Median nerve palsy

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve palsy

Explanation

The two-incision technique for distal biceps tendon repair was developed to decrease the risk of posterior interosseous nerve (PIN) injury, which was a historic concern with the single anterior incision approach. However, the two-incision approach carries a significantly higher risk of heterotopic ossification (specifically radioulnar synostosis), especially if the interosseous membrane is heavily breached or muscle bellies are traumatized. The single anterior incision is most commonly associated with lateral antebrachial cutaneous (LABC) nerve neurapraxia.

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