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Shoulder Arthroplasty & Arthritis MCQs

Practice Set 12 of 14

This practice set contains high-yield board review questions covering key concepts in Shoulder Arthroplasty & Arthritis. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 221

Topic: Shoulder Arthroplasty & Arthritis

Reverse total shoulder arthroplasty (RTSA) alters the biomechanics of the shoulder joint to compensate for a deficient rotator cuff. Which of the following best describes the biomechanical changes achieved by RTSA?

. Shifts the center of rotation superiorly and laterally
. Shifts the center of rotation inferiorly and medializes the humerus
. Increases the resting tension of the deltoid by superiorizing the humerus
. Decreases the moment arm of the deltoid muscle
. Shifts the center of rotation laterally to increase rotator cuff tension

Correct Answer & Explanation

. Shifts the center of rotation superiorly and laterally

Explanation

RTSA compensates for a massive, irreparable rotator cuff tear by moving the center of rotation medially and inferiorly. This medialization recruits more deltoid fibers, while the inferiorization lengthens the deltoid, increasing its resting tension and moment arm, allowing the deltoid to effectively elevate the arm without the help of the rotator cuff.

Question 222

Topic: Shoulder Arthroplasty & Arthritis

What is the most common radiographic complication specific to the Grammont-style reverse total shoulder arthroplasty, and how is it biomechanically prevented?

. Glenoid loosening; prevented by superior tilt of the glenosphere
. Scapular notching; prevented by inferior overhang and inferior tilt of the glenosphere
. Humeral stem subsidence; prevented by using a larger diaphyseal stem
. Acromial stress fracture; prevented by increased lateralization of the glenosphere
. Coracoid impingement; prevented by medializing the humeral component

Correct Answer & Explanation

. Glenoid loosening; prevented by superior tilt of the glenosphere

Explanation

Scapular notching is the most common radiographic finding/complication in Grammont-style RTSA. It occurs due to impingement of the medial humeral component against the inferior scapular neck during adduction. It is reduced by placing the glenosphere low on the native glenoid (with inferior overhang) and applying an inferior tilt.

Question 223

Topic: Shoulder Arthroplasty & Arthritis
A 65-year-old female sustains a proximal humerus fracture. Radiographs and CT show a 4-part fracture with complete lateral hinge disruption and a short calcar segment (<8 mm). What is the most appropriate definitive surgical management?
. Non-operative management in a sling
. Open reduction and internal fixation with a locking plate
. Hemiarthroplasty
. Reverse total shoulder arthroplasty
. Percutaneous pinning

Correct Answer & Explanation

. Reverse total shoulder arthroplasty

Explanation

In elderly patients with a 4-part proximal humerus fracture, especially with strong predictors of humeral head ischemia (disrupted medial hinge, short calcar <8mm, disrupted anatomic neck), reverse total shoulder arthroplasty (RTSA) provides more predictable outcomes and better forward elevation than ORIF or hemiarthroplasty. RTSA relies on the deltoid and does not depend on tuberosity healing for basic overhead function, though tuberosity repair improves rotation.

Question 224

Topic: Shoulder Arthroplasty & Arthritis

A 65-year-old female undergoes a reverse total shoulder arthroplasty for severe cuff tear arthropathy. Postoperatively, radiographs reveal scapular notching. According to the Sirveaux classification, what defines a Grade 3 notch?

. Notching confined to the scapular pillar
. Notching extending to the inferior screw
. Notching extending over and past the inferior screw
. Notching extending to the baseplate central peg
. Notching extending entirely through the glenoid vault

Correct Answer & Explanation

. Notching confined to the scapular pillar

Explanation

In the Sirveaux classification for scapular notching, Grade 1 is confined to the pillar, Grade 2 reaches the inferior screw, Grade 3 extends over the inferior screw, and Grade 4 reaches the central peg. Inferior positioning and eccentric inferior overhang of the glenosphere help prevent this complication.

Question 225

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female with osteoporosis sustains a severely displaced 4-part proximal humerus fracture. She lives independently and is functionally active. Which surgical intervention provides the most predictable functional outcome and pain relief in this demographic?

. Percutaneous pinning
. Intramedullary nailing
. Hemiarthroplasty
. Reverse total shoulder arthroplasty
. Non-operative management in a sling

Correct Answer & Explanation

. Percutaneous pinning

Explanation

Reverse total shoulder arthroplasty (RTSA) provides more predictable functional outcomes and better pain relief than ORIF or hemiarthroplasty for displaced 4-part proximal humerus fractures in the elderly. This is because RTSA relies on deltoid function rather than tuberosity healing for overhead elevation.

Question 226

Topic: Shoulder Arthroplasty & Arthritis

Scapular notching is a recognized complication of reverse total shoulder arthroplasty (RTSA), most commonly occurring at the inferior scapular neck. Which surgical technical modification reduces the incidence of inferior scapular notching?

. Superior placement of the glenosphere
. Superior tilt of the baseplate
. Medialization of the glenosphere
. Inferior overhanging of the glenosphere
. Increasing the neck-shaft angle of the humeral stem to 155 degrees

Correct Answer & Explanation

. Superior placement of the glenosphere

Explanation

Inferior overhang of the glenosphere (placing it flush or slightly overhanging the inferior glenoid rim) avoids mechanical impingement of the humeral polyethylene cup against the scapular neck during adduction, thus reducing scapular notching.

Question 227

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female is 3 years post-operative from a reverse total shoulder arthroplasty (RTSA) utilizing a Grammont-style prosthesis. Radiographs reveal bone loss on the scapular neck extending beyond the inferior screw of the baseplate. According to the Sirveaux classification, what grade is this scapular notching?

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

Correct Answer & Explanation

. Grade 1

Explanation

In the Sirveaux classification for scapular notching in RTSA, Grade 3 describes a notch that extends beyond the inferior screw of the glenoid baseplate. Grade 4 indicates extension up to the central peg.

Question 228

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 229

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 230

Topic: Shoulder Arthroplasty & Arthritis

A 78-year-old woman undergoes a reverse total shoulder arthroplasty for cuff tear arthropathy. Her preoperative, 3-month postoperative, and

. year postoperative radiographs are shown in Figures 1 through
. What is the cause of the radiographic finding seen here?17
. Glenoid component malposition
. Humeral component malposition
. Over tensioning of the deltoid

Correct Answer & Explanation

. year postoperative radiographs are shown in Figures 1 through

Explanation

The patient underwent a reverse arthroplasty for cuff tear arthropathy. Her preoperative radiograph shows some superior glenoid wear, which was not corrected at the time of surgery. This has resulted in superior tilt to the glenosphere, which has been identified as a risk factor for scapular notching. This occurs as a result of mechanical impingement between the medial humerus and scapular neck during arm adduction. The Beta angle and reverse shoulder angle have been proposed as measurements that can help identify pathologic glenoid tilt preoperatively. Risk factors for scapular notching include superior tilt of the glenosphere, superior placement of the glenoid baseplate on the glenoid, a 155° humeral implant angle, and incomplete lateralization of the construct.The humeral component appears well-positioned in this radiograph. Over tensioning of the deltoid and excessive humeral lateralization would risk an acromial stress fracture and could limit shoulder range of motion. This is an inlay humeral stem, which does not lateralize the humerus.

Question 231

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old male is 2 years post-operative from a reverse total shoulder arthroplasty (RTSA). Routine radiographs reveal prominent inferior scapular notching.

Which of the following surgical techniques or implant choices during the index procedure would have best minimized the risk of developing this complication?

. Superior placement of the glenosphere
. Inferior translation and inferior tilt of the glenosphere
. Superior tilt of the glenosphere
. Medialization of the center of rotation with a neutral tilt
. Decreasing the glenosphere size

Correct Answer & Explanation

. Superior placement of the glenosphere

Explanation

Scapular notching is a common complication following Grammont-style reverse total shoulder arthroplasty, caused by mechanical impingement of the humeral component against the inferior scapular neck during adduction. Techniques to minimize scapular notching include inferior translation of the glenosphere (overhanging the inferior rim by 2-4 mm), inferior tilt of the glenosphere, and using lateralized components (either a lateralized glenosphere or bony-increased offset [BIO] RTSA) to increase clearance between the humeral metaphysis and the scapular neck.

Question 232

Topic: Shoulder Arthroplasty & Arthritis

A 78-year-old female with osteoporosis sustains a severely comminuted 4-part proximal humerus fracture with head-splitting. Which of the following is the primary biomechanical advantage of treating this with a reverse total shoulder arthroplasty (RTSA) rather than a hemiarthroplasty?

. RTSA allows for better preservation of the native articular cartilage.
. RTSA restores normal anatomical center of rotation.
. RTSA relies entirely on intact tuberosities for forward elevation.
. RTSA relies on the deltoid and provides functional elevation despite tuberosity nonunion.
. RTSA prevents future rotator cuff tearing.

Correct Answer & Explanation

. RTSA allows for better preservation of the native articular cartilage.

Explanation

In elderly patients with poor bone quality, tuberosity healing is unreliable. RTSA is favored because it medializes and distalizes the center of rotation, maximizing the deltoid moment arm to provide forward elevation even if the tuberosities fail to heal.

Question 233

Topic: Shoulder Arthroplasty & Arthritis

In planning an anatomic total shoulder arthroplasty for primary osteoarthritis, a CT scan reveals a Walch B2 glenoid morphology. What specifically characterizes this type of glenoid wear?

. Symmetric concentric wear
. Biconcave glenoid with posterior wear and posterior subluxation
. Retroversion of >25 degrees with a dysplastic appearance
. Medialized wear without retroversion
. Anterior wear with anterior subluxation

Correct Answer & Explanation

. Symmetric concentric wear

Explanation

A Walch B2 glenoid is defined by biconcavity due to asymmetric posterior wear, often accompanied by posterior subluxation of the humeral head. This presents a high risk of glenoid component loosening if not addressed with eccentric reaming or augmented components.

Question 234

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old woman is 3 years status post a reverse total shoulder arthroplasty. Radiographs show inferior scapular notching extending past the inferior glenoid screw. Which surgical factor most effectively minimizes the risk of this complication?

. Superior placement of the glenosphere
. Neutral version of the humeral stem
. Inferior translation and inferior tilt of the glenosphere
. Decreasing the glenosphere size
. Medialization of the center of rotation

Correct Answer & Explanation

. Superior placement of the glenosphere

Explanation

Scapular notching is a frequent complication of reverse TSA caused by mechanical impingement of the humeral cup against the scapular neck. Inferior translation and inferior tilt of the glenosphere baseplate significantly reduce this risk.

Question 235

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old male who underwent a reverse total shoulder arthroplasty (RTSA) 6 months ago presents with new-onset lateral shoulder pain. Radiographs reveal a Levy Type II fracture at the base of the acromion. What is the most appropriate initial management?

. Open reduction and internal fixation with a tension band construct
. Sling immobilization and symptomatic treatment
. Revision to an anatomic total shoulder arthroplasty
. Arthroscopic subacromial decompression
. Immediate revision of the glenosphere to a smaller size

Correct Answer & Explanation

. Open reduction and internal fixation with a tension band construct

Explanation

Acromial stress fractures are a known complication of RTSA due to increased deltoid tension. Levy Type II fractures (located posterior to the acromioclavicular joint) are typically managed non-operatively with sling immobilization, although surgery may be considered for severe displacement or symptomatic nonunion.

Question 236

Topic: Shoulder Arthroplasty & Arthritis

A 74-year-old woman undergoes a reverse total shoulder arthroplasty (RTSA) for cuff tear arthropathy. How does the biomechanical design of the RTSA primarily improve her active shoulder elevation?

. It lateralizes the center of rotation to increase the rotator cuff lever arm.
. It shifts the center of rotation medially and inferiorly, increasing the deltoid lever arm.
. It relies on the preserved coracoacromial arch to provide a fulcrum.
. It shifts the center of rotation superiorly to tension the remaining supraspinatus.
. It increases the tension on the conjoint tendon to act as an elevator.

Correct Answer & Explanation

. It lateralizes the center of rotation to increase the rotator cuff lever arm.

Explanation

RTSA medializes and inferiorizes the center of rotation of the shoulder joint. This significantly recruits more deltoid fibers and increases the deltoid's moment arm, allowing it to compensate for the absent rotator cuff.

Question 237

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female presents with chronic shoulder pseudoparalysis and severe pain. Radiographs show superior migration of the humeral head with articulation against the acromion, and acetabularization of the coracoacromial arch (Hamada Stage 3). An MRI confirms a massive, irreparable rotator cuff tear. What is the most appropriate surgical intervention?

. Hemiarthroplasty
. Anatomic total shoulder arthroplasty
. Reverse total shoulder arthroplasty
. Superior capsular reconstruction
. Latissimus dorsi tendon transfer

Correct Answer & Explanation

. Hemiarthroplasty

Explanation

Reverse total shoulder arthroplasty (RTSA) is the treatment of choice for rotator cuff tear arthropathy with pseudoparalysis in older patients. It relies on the deltoid muscle to elevate the arm by medializing and distalizing the center of rotation, which increases the deltoid's moment arm. Anatomic TSA is contraindicated due to the deficient rotator cuff leading to early eccentric glenoid failure (the 'rocking horse' phenomenon).

Question 238

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female with pseudoparalysis secondary to severe rotator cuff tear arthropathy undergoes a reverse total shoulder arthroplasty (RTSA). According to Grammont's biomechanical principles, how does this prosthesis design improve the functional capacity of the deltoid muscle?

. By lateralizing and superiorly displacing the center of rotation
. By medializing and distalizing the center of rotation
. By increasing the anatomical retrotorsion of the humerus
. By preserving the anatomical center of rotation while increasing the humeral head diameter
. By translating the center of rotation anteriorly

Correct Answer & Explanation

. By medializing and distalizing the center of rotation

Explanation

Grammont's principles for RTSA involve medializing and distalizing the joint's center of rotation. This configuration increases the deltoid moment arm and tension, recruiting more deltoid fibers to elevate the arm in the absence of a functional rotator cuff.

Question 239

Topic: Shoulder Arthroplasty & Arthritis

A 65-year-old female presents with a 4-part proximal humerus fracture. In planning for a reverse total shoulder arthroplasty (rTSA) for this injury, anatomical repair and healing of the tuberosities are essential for which of the following?

. Restoring active forward elevation
. Restoring active external rotation
. Preventing anterior dislocation
. Enhancing deltoid tension
. Maximizing inferior offset

Correct Answer & Explanation

. Restoring active external rotation

Explanation

In a reverse total shoulder arthroplasty, the deltoid primarily powers forward elevation, but active external rotation requires an intact teres minor and infraspinatus. Healing of the greater tuberosity is therefore critical to restore active external rotation and improve overall functional outcomes.

Question 240

Topic: Shoulder Arthroplasty & Arthritis

Which of the following baseplate positions minimizes the risk of scapular notching in Reverse Total Shoulder Arthroplasty (RTSA)?

. 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

Scapular notching is a common complication of RTSA. To minimize impingement of the humeral component against the inferior scapular neck, the glenosphere baseplate should be placed with inferior translation (overhanging the inferior glenoid margin by 2-4 mm) and inferior tilt. This improves the impingement-free arc of motion and mechanical advantage of the deltoid.

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