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9. Shoulder and Elbow MCQs

Practice Set 85 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 1681

Topic: 9. Shoulder and Elbow
A 72-year-old woman with diabetes mellitus who underwent a total shoulder arthroplasty for degenerative arthritis 5 years ago now reports the sudden onset of shoulder pain following recent hospitalization for pneumonia. Laboratory values show a WBC count of 11,400/mm3 and an erythrocyte sedimentation rate of 52mm/h. What is the most appropriate action?
. Begin a stretching program.
. Obtain shoulder radiographs and aspirate the shoulder joint.
. Obtain an MRI scan to evaluate for a rotator cuff tear.
. Schedule for irrigation and debridement.
. Schedule for revision shoulder arthroplasty.

Correct Answer & Explanation

. Obtain shoulder radiographs and aspirate the shoulder joint.

Explanation

The patient has the preliminary diagnosis of an infected shoulder arthroplasty; therefore, shoulder radiographs and joint aspiration for organism identification should be the first steps in the work-up. The patient is at risk for hematogenous spread given the recent history of pneumonia and her history of diabetes mellitus. Although she has stiffness, a stretching program is not indicated with the possibility of infection. Scheduling for revision arthroplasty, or irrigation and debridement will depend on multiple factors including identification of the infecting organism, the organism's susceptibility to antibiotics, and implant stability. An MRI scan to evaluate for a rotator cuff tear is not indicated at this time.

Question 1682

Topic: Elbow & Forearm

A 45-year-old male sustains the injury pattern depicted in the provided image.

During surgical reconstruction of the lateral collateral ligament complex, identifying the correct isometric origin of the lateral ulnar collateral ligament (LUCL) on the distal humerus is critical. Where is this point located?

. At the center of the axis of rotation of the capitellum
. On the anterior border of the lateral epicondyle
. Directly on the tip of the olecranon
. At the supinator crest of the ulna
. 2 cm proximal to the lateral epicondyle

Correct Answer & Explanation

. At the center of the axis of rotation of the capitellum

Explanation

The isometric point for the LUCL origin on the humerus is the center of the axis of rotation of the capitellum. Placing a graft or suture anchor at this specific geometric location ensures that the reconstructed ligament maintains relatively constant tension throughout the elbow's entire arc of flexion and extension.

Question 1683

Topic: 9. Shoulder and Elbow

A 22-year-old collegiate baseball pitcher is diagnosed with a Type II SLAP (Superior Labrum Anterior and Posterior) lesion.

The 'peel-back' mechanism is thought to be the primary cause of this injury. During which phase of the throwing motion does this mechanism generate the maximum torsional force on the biceps anchor?

. Wind-up
. Early cocking
. Late cocking
. Acceleration
. Follow-through

Correct Answer & Explanation

. Late cocking

Explanation

The 'peel-back' mechanism occurs during the late cocking phase of throwing, when the shoulder is in maximal abduction and external rotation. In this position, the biceps vector shifts posteriorly, creating a torsional force that twists the biceps root and peels the superior labrum off the glenoid rim.

Question 1684

Topic: 9. Shoulder and Elbow
A 40-year-old female sustains a fall onto an outstretched hand, resulting in a 'terrible triad' injury of the elbow. She is taken to the operating room for open reduction and internal fixation. To systematically restore elbow stability, which of the following sequences of repair is most structurally appropriate and currently recommended?
. Radial head fixation/replacement → Lateral collateral ligament repair → Coronoid fixation
. Coronoid fixation → Radial head fixation/replacement → Lateral collateral ligament repair
. Lateral collateral ligament repair → Coronoid fixation → Radial head fixation/replacement
. Medial collateral ligament repair → Radial head fixation/replacement → Lateral collateral ligament repair
. Radial head fixation/replacement → Coronoid fixation → Medial collateral ligament repair

Correct Answer & Explanation

. Coronoid fixation → Radial head fixation/replacement → Lateral collateral ligament repair

Explanation

The terrible triad of the elbow consists of an elbow dislocation, a radial head fracture, and a coronoid fracture. The standard surgical protocol for restoring stability is an 'inside-out' or 'deep-to-superficial' approach. The coronoid (or anterior capsule) is repaired first to restore the anterior buttress. Next, the radial head is fixed or replaced to restore the anterior and valgus buttress. Finally, the lateral collateral ligament (LCL) complex is repaired to the lateral epicondyle to restore posterolateral rotatory stability. The MCL is typically only explored/repaired if the elbow remains unstable after these three steps.

Question 1685

Topic: Shoulder Arthroplasty & Arthritis



A 68-year-old male presents with severe, chronic shoulder pain and pseudoparalysis of active elevation. MRI reveals a massive, retracted tear of the supraspinatus and infraspinatus tendons with severe fatty infiltration (Goutallier stage 4) and superior migration of the humeral head. He has an intact, functioning deltoid muscle. Which surgical intervention provides the most reliable restoration of active elevation and pain relief?

. Arthroscopic primary rotator cuff repair with margin convergence
. Latissimus dorsi tendon transfer
. Reverse total shoulder arthroplasty (RTSA)
. Anatomic total shoulder arthroplasty (TSA)
. Superior capsular reconstruction (SCR)

Correct Answer & Explanation

. Reverse total shoulder arthroplasty (RTSA)

Explanation

In an older patient with an irreparable massive rotator cuff tear, pseudoparalysis, and severe fatty atrophy (Goutallier 3 or 4), a reverse total shoulder arthroplasty (RTSA) is the gold standard treatment. RTSA relies on the deltoid muscle to restore arm elevation by medializing and distalizing the center of rotation, effectively bypassing the deficient rotator cuff. Anatomic TSA is contraindicated due to the 'rocking horse' phenomenon, which leads to early glenoid component loosening in cuff-deficient shoulders.

Question 1686

Topic: Elbow & Forearm

In a patient with a high radial nerve palsy following a mid-shaft humerus fracture, tendon transfers are planned to restore function. Which of the following tendon transfers is the classic and most commonly utilized choice to restore wrist extension?

. Flexor carpi ulnaris (FCU) to Extensor digitorum communis (EDC)
. Flexor carpi radialis (FCR) to Extensor pollicis longus (EPL)
. Pronator teres (PT) to Extensor carpi radialis brevis (ECRB)
. Palmaris longus (PL) to Extensor carpi radialis longus (ECRL)
. Flexor digitorum superficialis (FDS) to Extensor carpi ulnaris (ECU)

Correct Answer & Explanation

. Pronator teres (PT) to Extensor carpi radialis brevis (ECRB)

Explanation

The classic transfer to restore wrist extension in a radial nerve palsy is the Pronator Teres (PT) transferred to the Extensor Carpi Radialis Brevis (ECRB). The ECRB is chosen over the ECRL because its central location on the wrist provides a more balanced extension without excessive radial deviation.

Question 1687

Topic: 9. Shoulder and Elbow

A 40-year-old gymnast falls on an outstretched hand, sustaining a 'Terrible Triad' injury of the elbow.

According to standard surgical protocols (e.g., Pugh and McKee), which of the following is the generally recommended sequence of surgical reconstruction to restore stability?

. Lateral collateral ligament (LCL) repair -> Coronoid fixation -> Radial head fixation/replacement -> Medial collateral ligament (MCL) repair
. Radial head fixation/replacement -> Coronoid fixation -> LCL repair -> MCL repair (if needed)
. Coronoid fixation -> Radial head fixation/replacement -> LCL repair -> MCL repair (if needed)
. MCL repair -> Coronoid fixation -> Radial head fixation/replacement -> LCL repair
. Coronoid fixation -> LCL repair -> Radial head fixation/replacement -> MCL repair

Correct Answer & Explanation

. Coronoid fixation -> Radial head fixation/replacement -> LCL repair -> MCL repair (if needed)

Explanation

The classic 'Terrible Triad' of the elbow includes an elbow dislocation, radial head fracture, and coronoid fracture. The standard inside-out surgical algorithm established by Pugh et al. starts deep/anterior and moves lateral: 1) Fixation or reconstruction of the coronoid process, 2) Fixation 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 steps, 4) Repair of the medial collateral ligament (MCL) or application of a hinged external fixator is indicated.

Question 1688

Topic: Shoulder Arthroplasty & Arthritis

When performing a reverse total shoulder arthroplasty for rotator cuff tear arthropathy, moving the center of rotation medially and inferiorly relative to the native anatomy accomplishes which of the following mechanical advantages?

. Decreases the deltoid moment arm and increases tension
. Increases the deltoid moment arm and increases inferior subluxation risk
. Increases the deltoid moment arm and decreases torque on the glenoid component
. Decreases the deltoid moment arm and increases torque on the glenoid component
. Increases the tension of the remaining rotator cuff muscles only

Correct Answer & Explanation

. Increases the deltoid moment arm and decreases torque on the glenoid component

Explanation

Grammont's principles for reverse total shoulder arthroplasty involve distalizing the humerus (to tension the deltoid) and medializing the center of rotation. Medialization increases the deltoid moment arm, improving its mechanical efficiency, and simultaneously reduces shear forces (torque) on the glenosphere, reducing the risk of aseptic loosening.

Question 1689

Topic: 9. Shoulder and Elbow

A 32-year-old female falls on an outstretched hand and sustains a 'terrible triad' injury of the elbow.

This injury pattern classically includes an elbow dislocation, a radial head fracture, and a fracture of which of the following structures?

. Olecranon
. Capitellum
. Coronoid process
. Lateral epicondyle
. Medial epicondyle

Correct Answer & Explanation

. Coronoid process

Explanation

The 'terrible triad' of the elbow is defined by the presence of a posterior or posterolateral elbow dislocation, a radial head fracture, and a fracture of the coronoid process. It is highly unstable and typically requires surgical intervention to restore the bony stabilizers (coronoid, radial head) and lateral collateral ligament complex.

Question 1690

Topic: 9. Shoulder and Elbow
A 25-year-old collegiate baseball pitcher presents with vague, deep shoulder pain and mechanical symptoms (clicking) during the late cocking phase of throwing. A magnetic resonance arthrogram demonstrates a tear of the superior labrum with complete detachment of the biceps tendon anchor from the superior glenoid rim. According to the Snyder classification, this represents which type of SLAP lesion?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

Type II SLAP (Superior Labrum Anterior to Posterior) lesions are the most common and are characterized by detachment of the superior labrum and the long head of the biceps anchor from the superior glenoid. Type I involves degenerative fraying with an intact biceps anchor. Type III is a bucket-handle tear of the labrum with an intact biceps anchor. Type IV is a bucket-handle tear of the labrum that extends directly into the substance of the biceps tendon.

Question 1691

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female with cuff tear arthropathy undergoes a reverse total shoulder arthroplasty (rTSA) using a Grammont-style prosthesis.

How does this classic implant design primarily alter the biomechanics of the shoulder to improve active elevation?

. Lateralizes the center of rotation to increase deltoid tension
. Medializes and distalizes the center of rotation to increase the deltoid moment arm
. Superiorly translates the center of rotation to recruit the intact lower subscapularis
. Medializes and proximalizes the center of rotation to decrease joint reactive forces
. Increases the offset of the humerus to restore the anatomical joint line

Correct Answer & Explanation

. Medializes and distalizes the center of rotation to increase the deltoid moment arm

Explanation

The classic Grammont-style reverse total shoulder arthroplasty (rTSA) alters shoulder biomechanics by medializing and distalizing the center of rotation. This effectively lengthens the deltoid muscle (increasing its tension) and significantly increases its moment arm, allowing the deltoid to effectively elevate the arm in the absence of a functional rotator cuff.

Question 1692

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female undergoes a reverse total shoulder arthroplasty (rTSA) for massive, irreparable cuff tear arthropathy.

By medializing and distalizing the center of rotation (COR), which of the following primary biomechanical advantages is achieved?

. Decreased deltoid moment arm
. Increased shear forces at the glenosphere-baseplate interface
. Increased deltoid moment arm and recruitment of anterior/posterior deltoid fibers
. Restoration of the normal anatomic center of rotation
. Increased tension on the remaining superior rotator cuff

Correct Answer & Explanation

. Increased deltoid moment arm and recruitment of anterior/posterior deltoid fibers

Explanation

Reverse total shoulder arthroplasty alters the biomechanics of the shoulder by medializing and distalizing the center of rotation. This significantly increases the moment arm of the deltoid, improving its mechanical advantage, and recruits more of the anterior and posterior deltoid fibers to assist with elevation in the absence of a functional rotator cuff.

Question 1693

Topic: 9. Shoulder and Elbow

A 72-year-old woman with chronic pseudoparalysis of the shoulder undergoes the procedure shown in the radiograph below. Which of the following is the most commonly reported radiographic complication specifically associated with this biomechanical implant design?

. Scapular notching
. Glenoid component aseptic loosening
. Acromial stress fracture
. Greater tuberosity nonunion
. Humeral stem subsidence

Correct Answer & Explanation

. Scapular notching

Explanation

The image depicts a reverse total shoulder arthroplasty (RTSA). Scapular notching, caused by mechanical impingement of the medial humeral metaphysis against the inferior scapular neck during adduction, is the most common radiographic complication. It is historically highest with medialized glenosphere and inlay humerus implant designs.

Question 1694

Topic: 9. Shoulder and Elbow

A 50-year-old man who underwent an arthroscopic rotator cuff repair 5 days ago now returns for an early postoperative follow-up because of increasing pain in his shoulder. He reports increasing malaise and has a low-grade fever. Examination reveals no redness or swelling, but he has scant serous drainage from the posterior portal. An emergent Gram stain is positive for gram-positive cocci. The next most appropriate step in management should consist of

. oral antibiotics and observation.
. IV antibiotics and observation.
. immediate arthroscopic debridement and lavage.
. blood cultures, oral antibiotics, and a reculture in 2 days.
. aspiration of the joint at his regular follow-up in 7 days if the symptoms increase.

Correct Answer & Explanation

. immediate arthroscopic debridement and lavage.

Explanation

An infection of the shoulder is considered a surgical emergency unless there are medical reasons that a patient cannot be taken to the operating room. If cultures of wound drainage are in question, then an aspiration should be done emergently, not several days later. The hallmark of infection in any major joint is increasing pain out of proportion to what is expected. Drainage occurring 1 to 2 days after an arthroscopic procedure is not normal, and it should be aggressively treated. Delay in diagnosis can result in sepsis and on a delayed basis, postinfectious arthritis. Both the glenohumeral joint and the subacromial space require debridement and irrigation, followed by antibiotics after both areas are cultured. Mansat P, Cofield RH, Kersten TE, Rowland CM: Complications of rotator cuff repair. Orthop Clin North Am 1997;28:205-213. Settecerri JJ, Pitner MA, Rock MG, Hanssen AD, Cofield RH: Infection after rotator cuff repair. J Shoulder Elbow Surg 1999;8:1-5. Ward WG, Eckardt JJ: Subacromial/subdeltoid bursa abscesses: An overlooked diagnosis. Clin Orthop 1993;288:189-194.

Question 1695

Topic: 9. Shoulder and Elbow

A 32-year-old man who works as a laborer has had left trapezius wasting and lateral scapular winging after injuring his shoulder when a cargo box fell onto his neck 8 months ago. He now reports posterior shoulder pain and fatigue, and he has difficulty shrugging his shoulder. Examination reveals marked scapular winging, impingement signs, and an asymmetrical appearance when the patient attempts a shoulder shrug. Primary scapular-trapezius winging is the result of damage to the

Orthopedic Surgery Board Review 2026 | High-Yield MCQs - Set 7 - Figure 53

. spinal accessory nerve, causing shoulder depression with the scapula translated laterally and the inferior angle rotated laterally.
. spinal accessory nerve, causing shoulder elevation with the scapula translated medially and the inferior angle rotated medially.
. long thoracic nerve, causing shoulder elevation with the scapula translated medially and the inferior angle rotated medially.
. long thoracic nerve, causing shoulder depression with the scapula translated laterally and the inferior angle rotated laterally.
. thoracodorsal nerve, causing shoulder depression with the scapula translated laterally and the inferior angle rotated laterally.

Correct Answer & Explanation

. spinal accessory nerve, causing shoulder depression with the scapula translated laterally and the inferior angle rotated laterally.

Explanation

The patient has primary scapular-trapezius winging. This condition can be caused by blunt trauma to the relatively superficial spinal accessory nerve that is located in the floor of the posterior cervical triangle in the subcutaneous tissue. Other causes of injury include penetrating trauma, traction, or surgical injury. With trapezius winging, the shoulder appears depressed and laterally translated because of an unopposed serratus anterior. This contrasts with primary serratus anterior winging, which is caused by injury to the long thoracic nerve. In this condition, the scapula assumes a position of superior elevation and medial translation, and the inferior angle is rotated medially. The thoracodorsal nerve supplies the latissimus dorsi and is not involved in primary scapular winging. Kuhn JE, Plancher KD, Hawkins RJ: Scapular winging. J Am Acad Orthop Surg 1995;3:319-325.

Question 1696

Topic: 9. Shoulder and Elbow

In the arthroscopic photograph shown in Figure 5, the structure labeled "A" functions primarily as a restraint to translation of the humeral head in what direction?

General Orthopedics Board Review 2026: High-Yield MCQs (Set 20) - Figure 46

. Inferiorly with the arm adducted to the side
. Anteriorly with the arm abducted to 45 degrees and at neutral rotation
. Anteriorly with the arm abducted to 45 degrees and maximally externally rotated
. Anteriorly with the arm abducted to 90 degrees and at neutral rotation
. Anteriorly with the arm abducted to 90 degrees and maximally externally rotated

Correct Answer & Explanation

. Anteriorly with the arm abducted to 90 degrees and maximally externally rotated

Explanation

The superior glenohumeral ligament identified as "A" in the figure functions primarily as a restraint to inferior glenohumeral translation of the adducted arm. The middle glenohumeral ligament is highly variable and pooly defined in up to 40% of the population and functions to restrain anterior translation of the externally rotated arm in the midrange of abduction. The anterior band of the inferior glenohumeral ligament is the primary restraint to anterior/inferior translation of the head with the shoulder abducted to 90 degrees and in maximum external rotation. Ticker JB, Bigliani LU, Soslowskiy LJ, et al: Inferior glenohumeral ligament: Geometric and strain-rate dependent properties. J Shoulder Elbow Surg 1996;5:269-279.

Question 1697

Topic: 9. Shoulder and Elbow

A 72-year-old male presents with chronic, intractable right shoulder pain and inability to actively elevate his arm above 60 degrees. X-rays

show severe glenohumeral osteoarthritis with significant superior migration of the humeral head and erosion of the acromion, consistent with rotator cuff arthropathy (Hamada Type IV). He has no prior shoulder surgery. Which of the following arthroplasty options is most likely to restore functional range of motion and pain relief?

. Hemiarthroplasty of the shoulder.
. Anatomic total shoulder arthroplasty (TSA).
. Reverse total shoulder arthroplasty (rTSA).
. Shoulder arthrodesis.
. Debridement arthroplasty.

Correct Answer & Explanation

. Reverse total shoulder arthroplasty (rTSA).

Explanation

The patient's presentation of chronic shoulder pain, pseudoparalysis (inability to actively elevate arm above 60 degrees), severe glenohumeral osteoarthritis, and superior migration of the humeral head with acromial erosion is characteristic of rotator cuff arthropathy (Hamada Type IV). In this condition, the rotator cuff is deficient and unable to stabilize the humeral head, leading to superior migration and eccentric glenohumeral arthritis.Anatomic total shoulder arthroplasty (TSA) (Option B) relies on an intact, functional rotator cuff for stability and active motion. It is contraindicated in rotator cuff arthropathy because the deficient cuff cannot center the humeral head, leading to early failure, instability, and poor outcomes.Hemiarthroplasty (Option A) also relies on the rotator cuff and often provides unpredictable pain relief and poor functional outcomes in the setting of rotator cuff arthropathy.Shoulder arthrodesis (Option D) provides pain relief and stability but at the expense of motion, which is generally not preferred for an active patient unless other options are contraindicated or failed.Debridement arthroplasty (Option E) is a palliative procedure for pain relief, often with limited functional improvement, and is typically reserved for low-demand patients or those unable to undergo more complex procedures.Reverse total shoulder arthroplasty (rTSA) (Option C) is the treatment of choice for rotator cuff arthropathy. The rTSA design medializes the center of rotation and recruits the deltoid muscle to power abduction and elevation, compensating for the deficient rotator cuff. It reliably improves pain and restores functional active elevation in patients with rotator cuff arthropathy. Therefore, rTSA is the most appropriate option to restore functional range of motion and pain relief for this patient.

Question 1698

Topic: 9. Shoulder and Elbow

A 68-year-old male presents with chronic, severe right shoulder pain and pseudoparalysis (inability to actively elevate the arm), despite extensive physical therapy and injections. MRI reveals a massive, retracted, irreparable posterosuperior rotator cuff tear with significant fatty infiltration (Goutallier Stage 3-4) of the supraspinatus and infraspinatus. Glenohumeral arthritis is mild (Samilson-Prieto Grade 1).

Which of the following treatment options is most likely to provide functional improvement and pain relief for this patient?

. Arthroscopic debridement and partial repair.
. Superior capsular reconstruction (SCR).
. Latissimus dorsi transfer.
. Reverse total shoulder arthroplasty (rTSA).
. Infraspinatus repair only.

Correct Answer & Explanation

. Reverse total shoulder arthroplasty (rTSA).

Explanation

The patient presents with pseudoparalysis, a massive irreparable rotator cuff tear with significant fatty infiltration, and mild glenohumeral arthritis. This clinical picture represents a classic indication for reverse total shoulder arthroplasty (rTSA).Option A (Arthroscopic debridement and partial repair) is unlikely to provide significant functional improvement or lasting pain relief in a massive, irreparable, chronically retracted tear with severe fatty infiltration. The tissue quality and retraction make healing improbable.Option B (Superior capsular reconstruction - SCR) is a reconstructive option for massive, irreparable rotator cuff tears without significant arthritis, particularly in younger, high-demand patients, aiming to restore the superior stabilizing force and prevent superior migration. However, in an older patient (68 years) with pseudoparalysis, rTSA often provides more reliable and predictable functional improvement.Option C (Latissimus dorsi transfer) is primarily indicated for irreparable posterosuperior rotator cuff tears with intact subscapularis and anterior deltoid function, and particularly for restoration of active external rotation and flexion/abduction. It may improve active elevation and external rotation, but rTSA often provides superior and more reliable functional gains for pseudoparalysis, especially in older patients.Option D (Reverse total shoulder arthroplasty - rTSA) is the most appropriate treatment for this patient. The rTSA design medializes the center of rotation and increases the deltoid lever arm, allowing the deltoid to effectively elevate and abduct the arm, thereby compensating for the irreparable rotator cuff deficiency and addressing the pseudoparalysis. It reliably provides pain relief and functional improvement in this specific scenario, even with mild glenohumeral arthritis. The image provided shows superior migration and possible acromial erosion, which are common findings in rotator cuff arthropathy, reinforcing the choice of rTSA.Option E (Infraspinatus repair only) is insufficient as it doesn't address the massive, irreparable nature of the tear affecting both supraspinatus and infraspinatus, or the pseudoparalysis.

Question 1699

Topic: Elbow & Forearm
A 40-year-old male sustains a severe fall onto his outstretched hand, resulting in an elbow fracture-dislocation. Radiographs and CT scans reveal a posteromedial coronoid fracture (Regan & Morrey Type III), a radial head fracture (Mason Type III), and disruption of the lateral ulnar collateral ligament (LUCL). This constellation of injuries is best described as what type of elbow instability?
. Posterolateral rotatory instability (PLRI).
. Terrible Triad injury of the elbow.
. Varus posteromedial rotatory instability (VPMRI).
. Pure elbow dislocation.
. Anterior instability of the elbow.

Correct Answer & Explanation

. Varus posteromedial rotatory instability (VPMRI).

Explanation

The described injury pattern—a posteromedial coronoid fracture, radial head fracture, and lateral ulnar collateral ligament (LUCL) disruption—is the classic 'Varus Posteromedial Rotatory Instability' (VPMRI) injury. This is a severe and often overlooked injury pattern that results from a varus force combined with axial loading and posterior external rotation. The posteromedial coronoid fracture is key, as it represents disruption of the anterior bundle of the medial collateral ligament (AMCL) attachment or an associated avulsion. The Terrible Triad injury involves a radial head fracture, coronoid fracture (usually anteromedial or tip), and LUCL disruption with posterior dislocation, and is distinct from VPMRI primarily by the coronoid fracture pattern and mechanism. PLRI involves isolated LUCL disruption. Pure elbow dislocation does not include associated fractures. Anterior instability is rare.

Question 1700

Topic: 9. Shoulder and Elbow

A 72-year-old female with irreparable rotator cuff arthropathy undergoes a reverse total shoulder arthroplasty. Postoperatively, she develops progressive pain and decreased range of motion, and radiographs reveal significant scapular notching.

Which of the following design or surgical implantation strategies is MOST effective in reducing the incidence of scapular notching in reverse total shoulder arthroplasty?

. Utilizing a smaller glenosphere diameter.
. Inferior glenosphere positioning or increased glenosphere lateralization.
. Increased polyethylene liner constraint.
. Superior humerus-glenoid offset.
. Medializing the center of rotation.

Correct Answer & Explanation

. Inferior glenosphere positioning or increased glenosphere lateralization.

Explanation

Scapular notching is a common complication of reverse total shoulder arthroplasty (RSA), caused by impingement of the polyethylene humeral liner on the inferior glenoid neck. The most effective strategies to reduce scapular notching involve increasing the distance between the humeral component and the inferior scapular neck. This can be achieved through: 1) Inferior positioning of the glenosphere on the glenoid, and 2) Increased glenosphere lateralization, either by using a lateralized glenosphere design or a lateralizing glenoid baseplate. These techniques effectively move the center of rotation more laterally and inferiorly, allowing greater range of motion before impingement occurs. A smaller glenosphere diameter would reduce lateralization, and medializing the center of rotation would increase notching.

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