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9. Shoulder and Elbow MCQs

Practice Set 124 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 2461

Topic: 9. Shoulder and Elbow

A 72-year-old man undergoes a reverse total shoulder arthroplasty (RTSA) for severe rotator cuff tear arthropathy. How does the biomechanical design of the Grammont reverse prosthesis improve active forward elevation compared to the native shoulder?

. It lateralizes the center of rotation and increases the deltoid moment arm.
. It medializes and distalizes the center of rotation, thereby increasing the deltoid moment arm.
. It superiorizes the center of rotation, increasing tension on the remaining rotator cuff.
. It medializes the center of rotation, which decreases the required deltoid force by increasing the lever arm of the supraspinatus.
. It anteriorizes the center of rotation, recruiting the pectoralis major for forward elevation.

Correct Answer & Explanation

. It medializes and distalizes the center of rotation, thereby increasing the deltoid moment arm.

Explanation

The Grammont design of reverse total shoulder arthroplasty medializes and distalizes the center of rotation of the glenohumeral joint. Medialization recruits more deltoid fibers (anterior and posterior) for elevation, while distalization tensions the deltoid and increases its moment arm, allowing the deltoid to effectively compensate for the deficient rotator cuff.

Question 2462

Topic: 9. Shoulder and Elbow

A 45-year-old male weightlifter feels a 'pop' in his anterior elbow while performing a heavy deadlift. Clinical examination and MRI confirm a complete rupture of the distal biceps tendon. If the patient elects for nonoperative management, which of the following best describes the expected persistent functional deficit?

. 30% loss of elbow flexion strength and 40% loss of forearm supination strength
. 40% loss of elbow flexion strength and 10% loss of forearm supination strength
. 10% loss of elbow flexion strength and 20% loss of forearm pronation strength
. 50% loss of elbow flexion strength and no loss of forearm supination strength
. Minimal loss of supination strength but 50% loss of elbow flexion strength

Correct Answer & Explanation

. 30% loss of elbow flexion strength and 40% loss of forearm supination strength

Explanation

Nonoperative management of distal biceps tendon ruptures results in a significant functional deficit, primarily in supination. Patients typically experience an approximately 40% loss of supination strength and a 30% loss of elbow flexion strength, along with decreased endurance.

Question 2463

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old woman undergoes reverse total shoulder arthroplasty for cuff tear arthropathy. Postoperatively, she does well but at 2-year follow-up, radiographs show grade 2 scapular notching. Which of the following surgical modifications would have most likely decreased the risk of this complication?

. Superior tilt of the glenosphere
. Superior placement of the baseplate
. Inferior placement of the glenosphere with overhang
. Decreasing the size of the glenosphere
. Medialization of the center of rotation

Correct Answer & Explanation

. Inferior placement of the glenosphere with overhang

Explanation

Scapular notching is a well-recognized complication of reverse total shoulder arthroplasty (RTSA), occurring when the medial aspect of the humeral tray impinges on the inferior scapular neck during adduction. Placing the glenosphere inferiorly with overhang, using a larger glenosphere, lateralizing the center of rotation, and applying an inferior tilt to the baseplate are technical modifications that reduce the risk of scapular notching. Superior placement, superior tilt, and medialization of the center of rotation increase the risk.

Question 2464

Topic: 9. Shoulder and Elbow

A 45-year-old manual laborer sustains a distal biceps tendon rupture after a sudden eccentric load to his flexed elbow. He wishes to pursue nonoperative management. He should be counseled that he will experience the greatest percentage loss of which of the following functional strengths?

. Forearm supination
. Forearm pronation
. Elbow flexion
. Elbow extension
. Grip strength

Correct Answer & Explanation

. Forearm supination

Explanation

Nonoperative management of distal biceps tendon ruptures results in permanent weakness. The greatest functional deficit is a loss of forearm supination strength, which decreases by approximately 40% to 50% compared to the contralateral side. Elbow flexion strength is also affected but to a lesser degree, typically decreasing by about 30%. Pronation and elbow extension strengths remain relatively unaffected.

Question 2465

Topic: Elbow & Forearm

A 45-year-old woman sustains a terrible triad injury of the elbow after a fall from a height. She is taken to the operating room for surgical stabilization. After standard surgical approaches are made and the joint is debrided of loose bodies, what is the most widely accepted sequence of reconstruction to restore elbow stability?

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

Correct Answer & Explanation

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

Explanation

The standard and most widely accepted surgical sequence for a terrible triad injury of the elbow proceeds from deep to superficial and anterior to posterior: first addressing the coronoid process, followed by the radial head, and finally the lateral ulnar collateral ligament (LUCL). If the elbow remains unstable after these structures are addressed, MCL repair or a hinged external fixator may be considered.

Question 2466

Topic: Shoulder Arthroplasty & Arthritis

Scapular notching is a well-documented complication of reverse total shoulder arthroplasty (rTSA). Which of the following baseplate and glenosphere positioning strategies is most strongly associated with a decreased incidence of inferior scapular notching?

. Superior translation and superior tilt
. Inferior translation and inferior tilt
. Medialization of the center of rotation
. Superior translation and inferior tilt
. Decreasing the lateral offset

Correct Answer & Explanation

. Inferior translation and inferior tilt

Explanation

Inferior translation and inferior tilt of the glenosphere, along with lateralization, help reduce the incidence of scapular notching. This positioning minimizes mechanical impingement of the medial aspect of the humeral component against the inferior scapular neck during arm adduction.

Question 2467

Topic: Elbow & Forearm

A 36-year-old man undergoes surgical repair of an acute, complete distal biceps tendon rupture using a single-incision anterior approach. Postoperatively, he complains of numbness and tingling extending down the radial aspect of his volar forearm. Which of the following nerves was most likely injured or stretched during the procedure?

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

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 emerges between the biceps and brachialis proximally and lies in the subcutaneous tissue laterally in the forearm. Vigorous retraction on the lateral side of the wound places it at high risk. The PIN is more classically at risk during a two-incision approach or if retractors are poorly placed over the radial neck.

Question 2468

Topic: 9. Shoulder and Elbow

Which of the following design modifications or surgical techniques is associated with a decreased incidence of scapular notching following a reverse total shoulder arthroplasty (RTSA)?

. Superior placement of the glenosphere
. Decreased lateral offset of the glenosphere (medialization)
. A larger neck-shaft angle of the humeral component (e.g., 155 degrees)
. Inferior translation and inferior tilt of the glenosphere
. Superior baseplate tilt

Correct Answer & Explanation

. Inferior translation and inferior tilt of the glenosphere

Explanation

Scapular notching is a well-known complication of reverse total shoulder arthroplasty (RTSA) caused by mechanical impingement of the humeral component against the inferior scapular neck during adduction. Techniques to decrease scapular notching include inferior translation (overhang) and inferior tilt of the glenosphere, as well as lateralization of the center of rotation (either via a lateralized glenosphere or bony increased-offset reverse shoulder arthroplasty [BIO-RSA]). A smaller neck-shaft angle (e.g., 135 degrees) is also associated with reduced notching compared to a larger angle (155 degrees). Superior placement, medialization, and superior tilt all increase the risk of notching.

Question 2469

Topic: Elbow & Forearm

During surgical reconstruction of a 'terrible triad' injury of the elbow, a surgeon sequentially performs a radial head arthroplasty and secures the coronoid fracture with a lasso suture technique. Intraoperative fluoroscopy reveals persistent posterolateral rotatory instability when the elbow is extended. What is the most appropriate next step in the surgical algorithm?

. Repair of the medial collateral ligament (MCL)
. Application of a hinged external fixator
. Repair of the lateral ulnar collateral ligament (LUCL)
. Cross-pinning of the radiocapitellar joint
. Fasciotomy of the forearm

Correct Answer & Explanation

. Repair of the lateral ulnar collateral ligament (LUCL)

Explanation

The terrible triad of the elbow consists of an elbow dislocation, radial head fracture, and coronoid fracture. The standard surgical algorithm dictates an outside-in or inside-out approach, prioritizing the restoration of deep osseous stabilizers before addressing the ligamentous structures. After the radial head and coronoid are stabilized (either by fixation or replacement), the lateral collateral ligament complex, specifically the lateral ulnar collateral ligament (LUCL), must be repaired to restore lateral stability and prevent posterolateral rotatory instability. Repair of the MCL or application of a hinged external fixator is reserved for cases where the elbow remains unstable despite osseous reconstruction and LUCL repair.

Question 2470

Topic: 9. Shoulder and Elbow

A 40-year-old woman falls on an outstretched hand and sustains an elbow injury. Computed tomography (CT) reveals a fracture of the capitellum extending into the lateral half of the trochlea, along with a separate, comminuted posterior structural fragment of the lateral column. Which of the following fixation strategies provides the most biomechanically stable construct for this specific injury pattern?

. Anterior-to-posterior (AP) headless compression screws only
. Posterior-to-anterior (PA) screws and a posterolateral buttress plate
. Excision of all fracture fragments and primary ligament repair
. Closed reduction and casting in 120 degrees of flexion
. Isolated medial column plating

Correct Answer & Explanation

. Posterior-to-anterior (PA) screws and a posterolateral buttress plate

Explanation

This fracture pattern describes a Dubberley Type 3B fracture (involvement of the capitellum and trochlea with posterior comminution). In Dubberley type B fractures, the lack of posterior cortical continuity severely compromises stability. Anterior-to-posterior (AP) headless compression screws alone are biomechanically insufficient and are associated with a high rate of fixation failure in the presence of posterior comminution. The most stable construct requires addressing the posterior defect, typically with a posterolateral buttress plate and posterior-to-anterior (PA) directed screws to support the articular fragments.

Question 2471

Topic: 9. Shoulder and Elbow

A 42-year-old woman falls on her outstretched hand and sustains a 'terrible triad' injury to her elbow. Which of the following is the most appropriate sequence of surgical reconstruction to restore elbow stability?

. Radial head fixation/replacement, coronoid fixation, LCL repair, MCL repair if persistently unstable
. Coronoid fixation, radial head fixation/replacement, LCL repair, MCL repair if persistently unstable
. LCL repair, coronoid fixation, radial head fixation/replacement, MCL repair if persistently unstable
. MCL repair, radial head fixation/replacement, LCL repair, coronoid fixation
. Radial head fixation/replacement, LCL repair, coronoid fixation, MCL repair

Correct Answer & Explanation

. Coronoid fixation, radial head fixation/replacement, LCL repair, MCL repair if persistently unstable

Explanation

The standard surgical protocol for a terrible triad injury (elbow dislocation, radial head fracture, coronoid fracture) proceeds from deep to superficial, or inside-out. The established sequence is: 1) Coronoid process fixation (to restore the anterior buttress), 2) Radial head fixation or replacement (to restore the lateral column), 3) Lateral collateral ligament (LCL) complex repair (typically torn off the lateral epicondyle), and 4) Medial collateral ligament (MCL) repair or application of a hinged external fixator if the elbow remains persistently unstable after the first three steps.

Question 2472

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old man with cuff tear arthropathy undergoes a reverse total shoulder arthroplasty. By medializing and inferiorly shifting the center of rotation, which of the following is the primary biomechanical advantage achieved?

. Decreases the deltoid moment arm and increases tension on the remaining rotator cuff
. Increases the deltoid moment arm and recruits more anterior and posterior deltoid fibers for elevation
. Restores the native anatomic center of rotation to optimize pectoralis major function
. Lateralizes the center of rotation to increase the resting tension of the deltoid
. Increases the superior translation of the humerus during active elevation

Correct Answer & Explanation

. Increases the deltoid moment arm and recruits more anterior and posterior deltoid fibers for elevation

Explanation

The Grammont principles of reverse total shoulder arthroplasty involve medializing and moving the center of rotation inferiorly relative to the native glenoid. This design significantly increases the deltoid moment arm and recruits more of the anterior and posterior deltoid fibers to assist in forward elevation and abduction. It also lowers the humerus (distalizes), thereby tensioning the deltoid and increasing its mechanical advantage, compensating for the functionally deficient rotator cuff.

Question 2473

Topic: Elbow & Forearm

A 6-year-old child presents with an acute Bado type I Monteggia fracture-dislocation (ulnar shaft fracture with anterior dislocation of the radial head). Following closed reduction of the ulnar shaft, the radial head remains anteriorly dislocated. What is the most appropriate next step in management?

. Open reduction of the radial head and annular ligament reconstruction
. Closed reduction of the radius and cast in extension
. Open reduction and internal fixation of the ulnar shaft fracture
. Excision of the radial head
. Application of an external fixator to the radius

Correct Answer & Explanation

. Open reduction and internal fixation of the ulnar shaft fracture

Explanation

In a pediatric Monteggia fracture-dislocation, the reduction of the radial head is entirely dependent on achieving anatomical length and alignment of the ulna. If closed reduction of the ulna fails to adequately reduce the radial head, or if the ulna alignment is lost, the next step is anatomic restoration of the ulna via ORIF or intramedullary nailing. Once the ulna is anatomically fixed, the radial head usually reduces spontaneously. Direct open reduction of the radial head is only indicated if it remains dislocated despite a perfectly anatomical ulnar reduction.

Question 2474

Topic: Shoulder Arthroplasty & Arthritis

A 75-year-old woman with a history of severe osteoporosis sustains a 4-part proximal humerus fracture. She is treated with a reverse total shoulder arthroplasty (rTSA). Which of the following tuberosity management strategies during the index procedure is most associated with improved functional outcomes?

. Excision of both the greater and lesser tuberosities
. Routine transfer of the latissimus dorsi
. Anatomic repair and healing of the greater tuberosity
. Nonanatomic healing of the tuberosities to the diaphysis
. Tenodesis of the long head of the biceps to the subscapularis

Correct Answer & Explanation

. Anatomic repair and healing of the greater tuberosity

Explanation

Reverse total shoulder arthroplasty (rTSA) has become an increasingly popular option for complex proximal humerus fractures in the elderly. While the prosthesis itself confers stability, anatomic healing of the tuberosities (particularly the greater tuberosity) is highly correlated with improved patient-reported outcomes, increased forward elevation, and enhanced external rotation. Nonunion, malunion, or excision of the tuberosities typically leads to poorer functional recovery.

Question 2475

Topic: 9. Shoulder and Elbow

A 42-year-old man falls from a height and sustains a 'terrible triad' injury of the elbow. Which of the following best describes the most appropriate sequence of surgical reconstruction?

. Fixation of the coronoid, followed by radial head replacement or fixation, and lateral collateral ligament (LCL) complex repair
. Lateral collateral ligament (LCL) complex repair, followed by radial head replacement or fixation, and coronoid fixation
. Medial collateral ligament (MCL) repair, followed by coronoid fixation, and lateral collateral ligament (LCL) complex repair
. Radial head replacement, followed by lateral collateral ligament (LCL) complex repair, and medial collateral ligament (MCL) repair
. Radial head excision, coronoid fixation, and medial collateral ligament (MCL) repair

Correct Answer & Explanation

. Fixation of the coronoid, followed by radial head replacement or fixation, and lateral collateral ligament (LCL) complex repair

Explanation

The terrible triad of the elbow involves an elbow dislocation, radial head fracture, and coronoid fracture. The surgical goal is to restore elbow stability to allow early range of motion. The standard treatment algorithm involves an 'inside-out' or deep-to-superficial approach. First, the coronoid is stabilized (often via a suture lasso or screw) to restore the anterior buttress. Next, the radial head is fixed or replaced to restore the radiocapitellar strut. Finally, the lateral collateral ligament (LCL) complex is repaired to the lateral epicondyle. If the elbow remains unstable after these steps, medial collateral ligament (MCL) repair or a hinged external fixator is considered.

Question 2476

Topic: Elbow & Forearm

A 45-year-old man undergoes surgical repair of a distal biceps tendon rupture via a single-incision anterior approach using a cortical button. Postoperatively, he reports numbness over the lateral aspect of his forearm. Which of the following nerves is most likely injured during this procedure?

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

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve

Explanation

The single-incision anterior approach for distal biceps tendon repair places the lateral antebrachial cutaneous nerve (LABCN) at greatest risk. The LABCN runs in the subcutaneous tissue lateral to the biceps tendon and can be injured during superficial dissection or by overzealous retraction. Injury to the posterior interosseous nerve (PIN) is classically associated with the two-incision technique if retractors are placed poorly around the radial neck, or if the tendon is passed through the interosseous membrane incorrectly.

Question 2477

Topic: Shoulder Pathology

A 25-year-old motorcyclist sustains a traumatic brachial plexus injury. Examination reveals paralysis of the rhomboids, serratus anterior, and all muscles of the upper extremity, accompanied by ipsilateral ptosis, miosis, and anhidrosis. What does this clinical picture indicate regarding the C8 and T1 nerve roots?

. Postganglionic rupture
. Incomplete neurapraxia
. Axonotmesis
. Preganglionic avulsion
. Intraspinal neuroma

Correct Answer & Explanation

. Preganglionic avulsion

Explanation

In brachial plexus trauma, distinguishing between preganglionic (avulsion) and postganglionic (rupture) injuries is critical for management. Horner syndrome (ptosis, miosis, anhidrosis) indicates disruption of the sympathetic chain, which exits the spinal cord via the T1 root proximally (preganglionic). Additionally, paralysis of the serratus anterior and rhomboids indicates involvement of the long thoracic and dorsal scapular nerves, respectively, which branch off very proximally from the roots. These signs collectively point to a preganglionic avulsion, which carries a poor prognosis for spontaneous recovery and typically requires nerve transfers rather than primary repair or grafting.

Question 2478

Topic: 9. Shoulder and Elbow

A 70-year-old woman presents with anterior shoulder pain and a sensation of instability 6 months after undergoing an anatomic total shoulder arthroplasty via a deltopectoral approach. Physical examination reveals a positive belly-press test, increased passive external rotation compared to the contralateral side, and profound weakness in internal rotation. Radiographs demonstrate anterior subluxation of the humeral head. What is the most appropriate and reliable surgical management?

. Revision of subscapularis repair with allograft augmentation
. Pectoralis major tendon transfer
. Revision to a Reverse Total Shoulder Arthroplasty (rTSA)
. Placement of an anterior bone block
. Closed reduction and shoulder spica casting

Correct Answer & Explanation

. Revision to a Reverse Total Shoulder Arthroplasty (rTSA)

Explanation

This patient has suffered a postoperative subscapularis failure after anatomic total shoulder arthroplasty, presenting with a positive belly-press test, increased passive external rotation, and anterior instability. In an older patient with secondary anterior instability following TSA, primary repair and tendon transfers (such as pectoralis major transfer) have high failure rates and less predictable outcomes. Revision to a reverse total shoulder arthroplasty (rTSA) provides a semiconstrained articulation that restores stability and function, making it the most reliable salvage procedure in this setting.

Question 2479

Topic: Elbow & Forearm

A 35-year-old woman falls on an outstretched hand and sustains a 'terrible triad' injury of the elbow, consisting of a posterior elbow dislocation, a comminuted radial head fracture, and a coronoid fracture. Which of the following ligamentous structures is the primary restraint to posterolateral rotatory instability (PLRI) and is invariably torn in this injury pattern?

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

Correct Answer & Explanation

. Lateral ulnar collateral ligament (LUCL)

Explanation

The terrible triad of the elbow results from a valgus, axial, and posterolateral rotatory force that causes sequential failure of the lateral and medial soft tissue constraints, along with fractures of the radial head and coronoid. The lateral ulnar collateral ligament (LUCL) is the primary restraint to posterolateral rotatory instability (PLRI). It is invariably torn in a terrible triad injury and must be securely repaired to the lateral epicondyle to restore elbow stability.

Question 2480

Topic: Shoulder Arthroplasty & Arthritis

When performing a reverse total shoulder arthroplasty (rTSA), placing the glenosphere with an inferior tilt and slight inferior overhang relative to the native glenoid margin is done primarily to minimize the risk of which of the following postoperative complications?

. Scapular notching
. Acromial stress fracture
. Glenoid baseplate loosening
. Anterior instability
. Infection

Correct Answer & Explanation

. Scapular notching

Explanation

Scapular notching is a well-known complication of reverse total shoulder arthroplasty, characterized by mechanical impingement of the medial humeral polyethylene cup against the inferior scapular neck during arm adduction. To minimize this, the glenosphere should be positioned with an inferior tilt and an inferior overhang past the inferior margin of the glenoid to prevent direct contact of the humeral component with the scapular pillar.

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