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9. Shoulder and Elbow MCQs

Practice Set 74 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 1461

Topic: 9. Shoulder and Elbow

A 65-year-old male with primary glenohumeral osteoarthritis is undergoing evaluation for a total shoulder arthroplasty. A CT scan of his shoulder reveals biconcave glenoid wear with retroversion of 20 degrees and posterior subluxation of the humeral head. Which Walch classification describes this glenoid morphology?

. Type A1
. Type B1
. Type B2
. Type B3
. Type C

Correct Answer & Explanation

. Type B2

Explanation

The Walch classification describes glenoid morphology in osteoarthritis. Type B2 is characterized by a biconcave glenoid with posterior subluxation of the humeral head and varying degrees of retroversion. Type B1 is posterior joint space narrowing without biconcavity. Type B3 is a monoconcave glenoid with severe retroversion (>15 degrees) and posterior subluxation. Type A represents central wear, and Type C is dysplastic.

Question 1462

Topic: 9. Shoulder and Elbow

Inferior scapular notching is a well-recognized complication after reverse total shoulder arthroplasty. Which surgical modification of the baseplate and glenosphere is most effective at reducing the incidence of this complication?

. Superior baseplate translation
. Increased superior tilt of the baseplate
. Inferior baseplate placement with inferior eccentric glenosphere offset
. Utilizing a smaller diameter glenosphere
. Decreased lateral offset of the glenosphere

Correct Answer & Explanation

. Inferior baseplate placement with inferior eccentric glenosphere offset

Explanation

Scapular notching occurs when the humeral component impinges on the inferior scapular neck during arm adduction. Inferior placement of the baseplate on the glenoid, using an eccentric glenosphere with inferior offset, and increasing the lateral offset of the glenosphere are the primary surgical strategies to prevent this mechanical impingement.

Question 1463

Topic: Shoulder Arthroplasty & Arthritis

Scapular notching is a well-recognized radiologic finding following reverse total shoulder arthroplasty (RTSA). Which of the following modifications in glenosphere positioning has been biomechanically and clinically proven to decrease the incidence of inferior scapular notching?

. Superior translation of the glenosphere
. Inferior placement of the glenosphere with inferior tilt
. Superior tilt of the glenosphere
. Neutral placement without any tilt
. Medialization of the center of rotation

Correct Answer & Explanation

. Inferior placement of the glenosphere with inferior tilt

Explanation

Scapular notching occurs when the medial aspect of the humeral component impinges against the inferior scapular neck during adduction. Placing the glenosphere flush or with a slight inferior overhang (2-4 mm) and applying inferior tilt minimizes this impingement by lowering the humerus relative to the scapular neck and improving the clearance for the humeral cup.

Question 1464

Topic: Shoulder Arthroplasty & Arthritis

A 62-year-old male is 5 weeks postoperative from a deltopectoral anatomic total shoulder arthroplasty. He reports a sudden 'pop' accompanied by pain and weakness while pushing a heavy door. Physical exam reveals increased passive external rotation compared to the contralateral side and a positive bear-hug test. What is the most appropriate management?

. Observation and physical therapy focused on internal rotation strengthening
. Immobilization in external rotation for 6 weeks
. Early surgical repair of the subscapularis
. Conversion to a reverse total shoulder arthroplasty
. Pectoralis major tendon transfer

Correct Answer & Explanation

. Early surgical repair of the subscapularis

Explanation

The patient's presentation (sudden pop, weakness, increased passive ER, positive bear-hug test) in the early postoperative period following an anatomic TSA via a deltopectoral approach is highly suspicious for an acute subscapularis tendon failure. Untreated, this can lead to anterior instability and devastating functional loss. Early surgical repair is the standard of care for acute traumatic failure of the subscapularis repair following TSA.

Question 1465

Topic: Shoulder Arthroplasty & Arthritis

Which design feature of a reverse total shoulder arthroplasty (RTSA) implant most effectively decreases the incidence of scapular notching?

. Medialized and superior placement of the glenosphere
. Increased neck-shaft angle of the humeral component
. Inferior placement of the glenosphere with overhang
. Use of a smaller diameter glenosphere
. Superior tilt of the glenoid baseplate

Correct Answer & Explanation

. Inferior placement of the glenosphere with overhang

Explanation

Scapular notching in RTSA is a common complication caused by impingement of the humeral component on the inferior scapular neck. Inferior placement of the glenosphere with a slight overhang past the inferior glenoid margin biomechanically reduces this impingement.

Question 1466

Topic: 9. Shoulder and Elbow

A 72-year-old female presents with severe primary glenohumeral osteoarthritis. MRI demonstrates an intact rotator cuff, but a CT scan reveals a Walch B3 glenoid with 25 degrees of retroversion. Which of the following is the most appropriate surgical treatment?

. Anatomic total shoulder arthroplasty with an asymmetric reaming
. Anatomic total shoulder arthroplasty with a posteriorly augmented glenoid
. Reverse total shoulder arthroplasty
. Hemiarthroplasty with concentric reaming
. Glenohumeral arthrodesis

Correct Answer & Explanation

. Reverse total shoulder arthroplasty

Explanation

In elderly patients with severe glenoid retroversion (Walch B2 or B3, often >15-20 degrees) and posterior subluxation, reverse total shoulder arthroplasty is increasingly preferred even with an intact rotator cuff to prevent the high rate of early glenoid loosening seen in anatomic TSA.

Question 1467

Topic: Elbow & Forearm

In the surgical management of a 'terrible triad' injury of the elbow, what is the generally recommended sequence of repair to best restore concentric stability?

. LCL repair, followed by coronoid fixation, then radial head repair
. Radial head repair, followed by LCL repair, then coronoid fixation
. MCL repair, followed by radial head repair, then coronoid fixation
. Coronoid fixation, followed by MCL repair, then LCL repair
. Coronoid fixation, followed by radial head repair/replacement, then LCL repair

Correct Answer & Explanation

. Coronoid fixation, followed by radial head repair/replacement, then LCL repair

Explanation

The terrible triad consists of an elbow dislocation, radial head fracture, and coronoid fracture. The standard sequence of repair is deep to superficial: coronoid fixation first, followed by radial head repair or arthroplasty, and finally lateral collateral ligament (LCL) repair, and finally evaluating the need for MCL repair or hinged ex-fix.

Question 1468

Topic: Shoulder Arthroplasty & Arthritis

In a reverse total shoulder arthroplasty, the center of rotation is moved medially and distally compared to native anatomy. How does this specific alteration biomechanically affect the deltoid muscle?

. It decreases the deltoid lever arm to reduce muscle fatigue
. It shifts the line of action laterally to reduce shear forces on the glenoid
. It increases the deltoid lever arm and tension, compensating for the deficient rotator cuff
. It recruits more anterior deltoid fibers for external rotation
. It relaxes the deltoid to allow the teres minor to act as the primary elevator

Correct Answer & Explanation

. It increases the deltoid lever arm and tension, compensating for the deficient rotator cuff

Explanation

Medializing and distalizing the center of rotation in an RTSA lengthens the deltoid lever arm and increases deltoid tension. This maximizes the mechanical advantage of the deltoid, allowing it to initiate and maintain forward elevation in the absence of a functioning supraspinatus.

Question 1469

Topic: Shoulder Arthroplasty & Arthritis

In reverse total shoulder arthroplasty (RTSA), inferior scapular notching is a recognized complication. Which of the following baseplate and glenosphere configurations minimizes the risk of this complication?

. Superior translation of the baseplate with a concentric glenosphere
. Superior tilt of the baseplate with an eccentric glenosphere
. Inferior translation of the baseplate with inferior overhang of the glenosphere
. Medialization of the center of rotation with a smaller glenosphere
. Use of a standard concentric glenosphere placed flush with the superior glenoid rim

Correct Answer & Explanation

. Inferior translation of the baseplate with inferior overhang of the glenosphere

Explanation

Inferior scapular notching is caused by mechanical impingement of the humeral component against the scapular neck. Inferior placement of the baseplate with inferior overhang of the glenosphere, along with a slightly inferior tilt, reduces impingement and minimizes notching.

Question 1470

Topic: 9. Shoulder and Elbow

In a reverse total shoulder arthroplasty, inferior tilt of the glenosphere baseplate is often recommended. What is the primary biomechanical advantage of placing the baseplate with an inferior tilt?

. It increases the deltoid wrapping angle and tension.
. It decreases the risk of inferior scapular notching.
. It shifts the center of rotation laterally to improve external rotation.
. It prevents superior subluxation of the humeral component.
. It limits impingement of the greater tuberosity on the acromion.

Correct Answer & Explanation

. It decreases the risk of inferior scapular notching.

Explanation

Inferior tilt of the glenosphere reduces the mechanical impingement of the humeral polyethylene cup against the inferior scapular neck during adduction. This significantly decreases the incidence of inferior scapular notching.

Question 1471

Topic: 9. Shoulder and Elbow

Which of the following biomechanical changes occurs following a properly implanted reverse total shoulder arthroplasty (RTSA) compared to the native shoulder anatomy?

. Medialization and inferiorization of the center of rotation
. Lateralization and superiorization of the center of rotation
. Medialization and superiorization of the center of rotation
. Lateralization and inferiorization of the center of rotation
. No change in the anatomic center of rotation

Correct Answer & Explanation

. Medialization and inferiorization of the center of rotation

Explanation

Reverse total shoulder arthroplasty (RTSA) alters normal shoulder biomechanics by medializing and inferiorizing the center of rotation. This increases the moment arm of the deltoid, recruits more of the anterior and posterior deltoid fibers, and increases the resting tension of the deltoid, allowing it to compensate for a deficient rotator cuff.

Question 1472

Topic: 9. Shoulder and Elbow

A 65-year-old male presents with persistent, vague shoulder pain 18 months after an anatomic total shoulder arthroplasty. Inflammatory markers (ESR, CRP) are within normal limits. Radiographs show early radiolucency around the glenoid peg. A joint aspirate is performed. Which of the following is the most appropriate step regarding the microbiological culture?

. Standard aerobic cultures for 3 days
. Hold anaerobic cultures for at least 14 days to detect Cutibacterium acnes
. Add acid-fast bacilli staining only
. Proceed to immediate two-stage revision without waiting for cultures
. Perform a leukocyte esterase test only

Correct Answer & Explanation

. Hold anaerobic cultures for at least 14 days to detect Cutibacterium acnes

Explanation

Cutibacterium acnes (formerly Propionibacterium acnes) is an indolent, slow-growing anaerobic Gram-positive bacillus commonly responsible for periprosthetic shoulder infections. It often presents with a normal ESR and CRP. Cultures must be held for 14 to 21 days to accurately detect it.

Question 1473

Topic: Elbow & Forearm

In the surgical management of a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, coronoid fracture), which of the following represents the most widely accepted sequence of repair through a lateral approach?

. Radial head, coronoid, lateral collateral ligament (LCL), medial collateral ligament (MCL) if needed
. Coronoid, LCL, radial head, MCL if needed
. Coronoid, radial head, LCL, MCL if needed
. LCL, radial head, coronoid, MCL if needed
. MCL, coronoid, radial head, LCL

Correct Answer & Explanation

. Coronoid, radial head, LCL, MCL if needed

Explanation

The standard surgical sequence for a terrible triad is 'deep to superficial' (or medial to lateral) from the lateral approach: repair/fix the coronoid first (often visualizing it through the defect left by the fractured radial head), then repair or replace the radial head, then repair the LCL complex. The MCL is typically only addressed if the elbow remains unstable in extension after the lateral-sided and intra-articular repairs are complete.

Question 1474

Topic: 9. Shoulder and Elbow

A 62-year-old female undergoes an anatomic total shoulder arthroplasty via a deltopectoral approach. Six weeks postoperatively, she describes feeling a 'pop' while pushing open a heavy door. She subsequently demonstrates increased passive external rotation and weakness in internal rotation. What is the most likely diagnosis?

. Deltoid dehiscence
. Subscapularis tendon rupture
. Pectoralis major rupture
. Anterior inferior glenohumeral ligament tear
. Glenoid component loosening

Correct Answer & Explanation

. Subscapularis tendon rupture

Explanation

Subscapularis failure is a known and serious complication after anatomic TSA, as the tendon is often peeled, tenotomized, or osteotomized during the standard deltopectoral approach. Presentation includes a sudden 'pop', unexpectedly increased passive external rotation, weakness in internal rotation (positive lift-off or belly-press tests), and sometimes anterior instability.

Question 1475

Topic: Shoulder Pathology

A 30-year-old male complains of right shoulder weakness and a prominent shoulder blade after a heavy traction injury to his neck and shoulder. On examination, there is marked prominence of the medial border of the scapula, especially when pushing against a wall. Injury to which of the following nerves is the most likely cause?

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

Correct Answer & Explanation

. Long thoracic nerve

Explanation

Medial scapular winging (prominence of the medial border) is caused by serratus anterior palsy, which is innervated by the long thoracic nerve (C5, C6, C7). Lateral winging is caused by trapezius palsy, which is innervated by the spinal accessory nerve.

Question 1476

Topic: 9. Shoulder and Elbow

A 72-year-old female presents with pseudoparalysis of the right shoulder. Radiographs reveal an acromiohumeral interval of 3 mm, acetabularization of the acromion, and femoralization of the humeral head, but no distinct glenohumeral joint space narrowing. According to the Hamada classification for rotator cuff tear arthropathy, what is her grade?

. Grade 1
. Grade 2
. Grade 3
. Grade 4
. Grade 5

Correct Answer & Explanation

. Grade 3

Explanation

Hamada classification: Grade 1: Acromiohumeral interval (AHI) > 6 mm. Grade 2: AHI < 7 mm (often < 5 mm). Grade 3: Acetabularization of the acromion. Grade 4: Glenohumeral arthritis (narrowed joint space). Grade 5: Humeral head collapse (osteonecrosis). This patient has Grade 3.

Question 1477

Topic: Shoulder Arthroplasty & Arthritis

A 78-year-old female sustains a displaced 4-part proximal humerus fracture. Which of the following factors makes primary reverse total shoulder arthroplasty (RTSA) a more appropriate choice than open reduction internal fixation (ORIF) or anatomic hemiarthroplasty?

. An intact and healthy rotator cuff
. Medial calcar hinge length of 15 mm
. Tuberosity displacement of 5 mm
. Advanced age with pre-existing severe rotator cuff tear
. An isolated greater tuberosity fracture

Correct Answer & Explanation

. Advanced age with pre-existing severe rotator cuff tear

Explanation

RTSA is highly indicated in elderly patients with 4-part proximal humerus fractures, particularly in the setting of pre-existing rotator cuff dysfunction (cuff tear arthropathy) or when bone quality makes tuberosity healing doubtful. Hemiarthroplasty relies heavily on tuberosity healing for good function, and ORIF has high failure rates in elderly osteoporotic bone with comminution.

Question 1478

Topic: Elbow & Forearm

A 45-year-old female falls on an outstretched hand and sustains a capitellum fracture. The fracture extends medially to include the lateral aspect of the trochlea, but the posterior condylar bone remains intact. According to the Dubberley classification, what type of fracture is this?

. Type 1A
. Type 2A
. Type 3A
. Type 1B
. Type 2B

Correct Answer & Explanation

. Type 2A

Explanation

Dubberley classification of capitellum fractures: Type 1: involves capitellum with or without lateral trochlear ridge. Type 2: involves capitellum and lateral trochlea as a single piece. Type 3: comminuted capitellum and lateral trochlea. 'A' indicates the posterior condyle is intact; 'B' indicates a posterior condylar fracture (loss of posterior support). The described fracture is Type 2A.

Question 1479

Topic: Shoulder Arthroplasty & Arthritis

Scapular notching is a common radiographic finding after reverse total shoulder arthroplasty (RTSA). According to the Sirveaux classification, a notch that extends past the inferior screw of the glenoid baseplate is classified as:

. Grade 1
. Grade 2
. Grade 3
. Grade 4
. Grade 5

Correct Answer & Explanation

. Grade 2

Explanation

Sirveaux classification of scapular notching: Grade 1: Notching confined to the scapular pillar. Grade 2: Notching reaches the inferior screw of the baseplate. Grade 3: Notching extends past the inferior screw. Grade 4: Notching extends to the central peg.

Question 1480

Topic: 9. Shoulder and Elbow

A 17-year-old football player sustains a posterior sternoclavicular joint dislocation. He complains of hoarseness and difficulty swallowing. After a careful assessment by a multidisciplinary team, closed reduction in the operating room is planned. What is the most appropriate technique for reduction?

. Anterior pressure on the medial clavicle with the shoulder protracted
. Lateral traction on the abducted arm with anteriorly directed force to the medial clavicle
. Pushing the clavicle further posteriorly to unlock it before anterior translation
. Inferior traction on the arm with the elbow fully extended
. Maximum shoulder internal rotation while applying a posterior force

Correct Answer & Explanation

. Lateral traction on the abducted arm with anteriorly directed force to the medial clavicle

Explanation

For posterior SC joint dislocation, closed reduction is typically performed with a bolster between the scapulae. Lateral traction on the abducted arm is applied, and a towel clip or fingers are used to grasp the medial clavicle and pull it anteriorly. Thoracic surgery backup should be available due to the proximity of mediastinal structures (trachea, esophagus, great vessels).

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