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9. Shoulder and Elbow MCQs

Practice Set 142 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 2821

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female undergoes a reverse total shoulder arthroplasty (rTSA) utilizing a standard Grammont-style prosthesis for the treatment of severe rotator cuff tear arthropathy. Postoperatively, she demonstrates excellent active forward elevation to 150 degrees but complains of profound weakness and inability to actively externally rotate her arm. Which biomechanical alteration inherent to this specific rTSA design primarily explains her functional deficit?

. Medialization of the center of rotation decreasing the tension and moment arm of the posterior rotator cuff.
. Inferiorization of the center of rotation increasing the tension on the remaining teres minor.
. Lateralization of the center of rotation increasing the moment arm of the anterior deltoid.
. Superiorization of the center of rotation leading to mechanical disadvantage of the coracobrachialis.
. Excessive retroversion of the humeral component leading to posterior impingement.

Correct Answer & Explanation

. Medialization of the center of rotation decreasing the tension and moment arm of the posterior rotator cuff.

Explanation

Correct Answer: AThe standard Grammont-style reverse total shoulder arthroplasty (rTSA) biomechanically functions by medializing and inferiorizing the center of rotation of the glenohumeral joint. While inferiorization recruits more deltoid fibers and increases its moment arm for forward elevation, the medialization of the center of rotation significantly decreases the resting tension and the moment arm of the posterior rotator cuff (infraspinatus and teres minor). This biomechanical disadvantage often results in decreased active external rotation, a common clinical finding post-rTSA, especially if the posterior cuff is already compromised or absent. Newer lateralized rTSA designs attempt to restore this tension to improve external rotation. Options B, C, and D incorrectly describe the biomechanical shifts of a Grammont prosthesis. Option E is a technical error but not the primary inherent design reason for this specific, predictable deficit.

Question 2822

Topic: Elbow & Forearm

A 34-year-old female presents with recurrent elbow clicking and a sensation of the elbow "giving out" when she pushes herself up from a chair. She has a history of a prior elbow dislocation treated non-operatively 2 years ago. Which of the following physical examination maneuvers is most specific for diagnosing her underlying pathology?

. Moving valgus stress test
. Milking maneuver
. Lateral pivot-shift test of the elbow
. Hook test
. Tinel's sign at the cubital tunnel

Correct Answer & Explanation

. Lateral pivot-shift test of the elbow

Explanation

Correct Answer: CThis patient's history of a prior dislocation and symptoms of the elbow "giving out" when pushing up from a chair (which applies an axial load, valgus stress, and supination to the elbow) are classic for posterolateral rotatory instability (PLRI). PLRI is caused by insufficiency of the lateral ulnar collateral ligament (LUCL). The most specific physical examination test for PLRI is the lateral pivot-shift test of the elbow (or the posterolateral rotatory apprehension test). The moving valgus stress test and milking maneuver evaluate the medial ulnar collateral ligament (MUCL) for valgus instability. The hook test is used to diagnose distal biceps tendon ruptures. Tinel's sign evaluates for cubital tunnel syndrome.

Question 2823

Topic: 9. Shoulder and Elbow
A 50-year-old female with poorly controlled type 1 diabetes presents with severe shoulder stiffness and pain, consistent with the "freezing" stage of adhesive capsulitis. If a biopsy of her glenohumeral joint capsule were performed, histological analysis would most likely reveal an abundance of which of the following cell types and associated cytokines?
. Neutrophils and Interleukin-1 (IL-1)
. Fibroblasts and Transforming Growth Factor-beta (TGF-β)
. Osteoclasts and Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL)
. Lymphocytes and Tumor Necrosis Factor-alpha (TNF-α)
. Chondrocytes and Matrix Metalloproteinase-13 (MMP-13)

Correct Answer & Explanation

. Fibroblasts and Transforming Growth Factor-beta (TGF-β)

Explanation

Adhesive capsulitis (frozen shoulder) is fundamentally a fibrotic disease process of the glenohumeral joint capsule, particularly affecting the rotator interval and anterior capsule. Histologically, it is characterized by a dense proliferation of fibroblasts and myofibroblasts, leading to excessive type III collagen deposition and subsequent capsular contracture. The primary cytokine driving this profibrotic cascade is Transforming Growth Factor-beta (TGF-β), along with Platelet-Derived Growth Factor (PDGF). It is not primarily an acute inflammatory process (neutrophils/IL-1), a bone resorptive process (osteoclasts/RANKL), or a cartilage degenerative process (chondrocytes/MMP-13).

Question 2824

Topic: Elbow & Forearm
A 35-year-old female falls on an outstretched hand and sustains a shear fracture of the articular surface of the capitellum. Radiographs and CT imaging reveal that the fracture fragment consists almost entirely of articular cartilage with very little attached subchondral bone, often described as an "uncapping" of the condyle. According to the Bryan and Morrey classification, what type of fracture is this?
. Type I (Hahn-Steinthal)
. Type II (Kocher-Lorenz)
. Type III (Broberg-Morrey)
. Type IV (McKee)
. Type V (Jupiter)

Correct Answer & Explanation

. Type II (Kocher-Lorenz)

Explanation

The Bryan and Morrey classification describes fractures of the capitellum. A Type I fracture (Hahn-Steinthal) involves a large osseous piece of the capitellum, often including a portion of the lateral trochlea. A Type II fracture (Kocher-Lorenz) is a shear fracture involving primarily the articular cartilage with very little subchondral bone, often referred to as an "uncapping" of the capitellum. A Type III fracture (Broberg-Morrey) is a severely comminuted fracture of the capitellum. A Type IV fracture (McKee modification) is a coronal shear fracture that includes the capitellum and the majority of the trochlea. The vignette specifically describes the classic Kocher-Lorenz (Type II) pattern.

Question 2825

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female presents with progressive shoulder pain three years after undergoing a reverse total shoulder arthroplasty (rTSA) for rotator cuff tear arthropathy. Radiographs reveal Grade 3 scapular notching. Which of the following intraoperative technical errors during the initial surgery most likely contributed to this complication?

. Inferior tilt of the glenosphere.
. Superior placement of the metaglene (baseplate).
. Placement of the glenosphere in 10 degrees of retroversion.
. Use of a lateralized humeral stem.
. Oversizing the glenosphere component.

Correct Answer & Explanation

. Superior placement of the metaglene (baseplate).

Explanation

Correct Answer: BScapular notching is a well-documented complication unique to reverse total shoulder arthroplasty (rTSA), occurring when the medial aspect of the humeral component impinges against the inferior scapular neck during arm adduction. To minimize this risk, the current biomechanical consensus recommends placing the metaglene (baseplate) flush with or slightly overhanging the inferior glenoid rim, and utilizing an inferior tilt (typically 10 to 20 degrees). Superior placement of the metaglene fails to clear the inferior scapular pillar, leading to early impingement and subsequent mechanical wear (notching) of the bone. Inferior tilt (Option A) and lateralization (Option D) are actually techniques used topreventnotching. Retroversion (Option C) primarily affects anterior-posterior stability, and oversizing the glenosphere (Option E) generally increases the offset, which can also help reduce notching rather than cause it.

Question 2826

Topic: Elbow & Forearm

A 45-year-old male is undergoing surgical reconstruction for a "Terrible Triad" injury of the elbow (posterior dislocation, radial head fracture, and coronoid fracture). To systematically restore elbow stability, what is the most widely accepted sequence of surgical repair?

. Lateral ulnar collateral ligament (LUCL) repair, followed by radial head fixation, followed by coronoid fixation.
. Coronoid fixation, followed by radial head fixation or replacement, followed by LUCL repair.
. Medial ulnar collateral ligament (MUCL) repair, followed by LUCL repair, followed by radial head replacement.
. Radial head replacement, followed by MUCL repair, followed by coronoid fixation.
. Coronoid fixation, followed by MUCL repair, followed by LUCL repair.

Correct Answer & Explanation

. Coronoid fixation, followed by radial head fixation or replacement, followed by LUCL repair.

Explanation

Correct Answer: BThe standard surgical protocol for treating a Terrible Triad injury of the elbow follows a "deep to superficial" and "inside-out" approach to systematically restore stability. The accepted sequence is: 1) Fixation of the coronoid process (or repair of the anterior capsule if the fragment is too small), which restores the anterior buttress. 2) Fixation or replacement of the radial head, which restores the anterior and valgus buttress. 3) Repair of the lateral ulnar collateral ligament (LUCL) complex, which restores posterolateral rotatory stability. The medial ulnar collateral ligament (MUCL) is typically only repaired if the elbow remains unstable in extension after the first three steps have been completed. Repairing the LUCL first would restrict access to the deeper intra-articular structures (coronoid and radial head).

Question 2827

Topic: Elbow & Forearm

A 45-year-old female undergoes surgical debridement of the extensor carpi radialis brevis (ECRB) origin for refractory lateral epicondylitis. Which of the following best describes the characteristic histological findings expected in the excised tissue?

. Dense infiltration of polymorphonuclear leukocytes and macrophages.
. Angiofibroblastic tendinosis with disorganized collagen and neovascularization.
. Granulomatous inflammation with multinucleated giant cells.
. Fibrinoid necrosis of the blood vessel walls.
. Abundant normal tenocytes with parallel, highly organized type I collagen bundles.

Correct Answer & Explanation

. Angiofibroblastic tendinosis with disorganized collagen and neovascularization.

Explanation

Correct Answer: BLateral epicondylitis ("tennis elbow") is clinically termed an "-itis," but histologically it is a degenerative tendinopathy rather than an acute inflammatory process. The classic histological description, coined by Nirschl, is "angiofibroblastic hyperplasia" or "angiofibroblastic tendinosis." This is characterized by disorganized, immature collagen fibers, an absence of acute inflammatory cells (like polymorphonuclear leukocytes), an increase in ground substance, and prominent neovascularization (fibroblastic and vascular response). This degenerative tissue fails to heal properly due to repetitive microtrauma. Therefore, options suggesting acute inflammation, granulomas, or normal healthy tendon are incorrect.

Question 2828

Topic: 9. Shoulder and Elbow

A 42-year-old male sustains an acute, complete rupture of his distal biceps tendon. He is a sedentary office worker and opts for non-operative management. He should be counseled to expect the greatest permanent functional deficit in which of the following motions?

. Elbow flexion.
. Elbow extension.
. Forearm pronation.
. Forearm supination.
. Shoulder forward elevation.

Correct Answer & Explanation

. Forearm supination.

Explanation

Correct Answer: DThe biceps brachii is a powerful flexor of the elbow, but its primary and most powerful biomechanical role is as a supinator of the forearm, especially when the elbow is flexed. If a complete distal biceps tendon rupture is left untreated, the brachialis muscle can largely compensate for elbow flexion, resulting in a relatively modest loss of flexion strength (typically around 30%). However, there is no muscle that can fully compensate for the loss of the biceps in supination. Consequently, patients managed non-operatively experience a significant and permanent loss of forearm supination strength, typically ranging from 40% to 50%, along with a decrease in supination endurance.

Question 2829

Topic: 9. Shoulder and Elbow

A 72-year-old female undergoes a reverse total shoulder arthroplasty (rTSA) for severe rotator cuff tear arthropathy. The fundamental design of the rTSA prosthesis alters the native biomechanics of the glenohumeral joint. What is the primary biomechanical advantage achieved by medializing and inferiorizing the center of rotation in this procedure?

. Increases the resting tension of the remaining rotator cuff musculature.
. Increases the moment arm and mechanical advantage of the deltoid muscle.
. Restores the anatomic center of rotation of the native glenohumeral joint.
. Decreases the compressive forces across the glenohumeral joint interface.
. Prevents scapular notching by increasing the acromiohumeral interval.

Correct Answer & Explanation

. Increases the moment arm and mechanical advantage of the deltoid muscle.

Explanation

Correct Answer: BThe fundamental biomechanical principle of the reverse total shoulder arthroplasty (rTSA), originally designed by Paul Grammont, is the medialization and inferiorization of the glenohumeral center of rotation. By moving the center of rotation medially, the moment arm of the deltoid muscle is significantly increased, which enhances its mechanical advantage and allows it to elevate the arm even in the absence of a functional rotator cuff. Inferiorizing the center of rotation tensions the deltoid, further optimizing its length-tension relationship and increasing its compressive force across the joint, which aids in stability. The rTSA doesnotrestore the native anatomic center of rotation (Option C); it intentionally alters it. Medialization actually increases the risk of scapular notching (Option E), which is why modern designs often incorporate lateralized glenospheres or eccentric glenospheres to mitigate this, though the primary biomechanical driver remains deltoid optimization. Compressive forces are increased, not decreased, to provide stability (Option D).

Question 2830

Topic: 9. Shoulder and Elbow

A 34-year-old female gymnast complains of recurrent clicking and a sensation of her elbow "giving out" when pushing up from a chair. She has a history of a prior elbow dislocation treated non-operatively 2 years ago. You suspect posterolateral rotatory instability (PLRI). Which combination of forces is applied during the most appropriate provocative physical examination maneuver to diagnose this condition?

. Pronation, varus stress, and axial load during elbow extension
. Supination, valgus stress, and axial load during elbow flexion
. Pronation, valgus stress, and axial load during elbow flexion
. Supination, varus stress, and axial load during elbow extension
. Neutral rotation, valgus stress, and distraction during elbow flexion

Correct Answer & Explanation

. Supination, valgus stress, and axial load during elbow flexion

Explanation

Correct Answer: BThe patient's history and symptoms are classic for posterolateral rotatory instability (PLRI) of the elbow, which results from insufficiency of the lateral ulnar collateral ligament (LUCL). The most appropriate provocative test is the lateral pivot-shift test of the elbow. This test is performed with the patient supine and the arm overhead. The examiner applies a combination ofsupination, valgus stress, and an axial loadwhile slowly flexing the elbow from a fully extended position. This maneuver causes the radial head to subluxate posterolaterally. As flexion continues past approximately 40 degrees, the triceps and brachialis pull the joint back into a reduced position, often with a palpable or audible "clunk." Pronation and varus stress (Option A) do not recreate the posterolateral subluxation mechanism. Valgus stress with pronation (Option C) tests the medial collateral ligament.

Question 2831

Topic: Elbow & Forearm

A 45-year-old weightlifter undergoes a single-incision anterior approach for the repair of an acute distal biceps tendon rupture. Postoperatively, he demonstrates an inability to extend his fingers at the metacarpophalangeal (MCP) joints, but his wrist extension is preserved, albeit with radial deviation. Which nerve was most likely injured during the surgical procedure?

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

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

Correct Answer: CThe posterior interosseous nerve (PIN), a motor branch of the radial nerve, is at significant risk during the anterior single-incision approach for distal biceps repair, particularly if retractors are placed blindly or aggressively around the radial neck. The PIN innervates the extensor digitorum communis (EDC), extensor carpi ulnaris (ECU), and other extensors. Injury results in the inability to extend the fingers at the MCP joints. Wrist extension is preserved but occurs with radial deviation because the extensor carpi radialis longus (ECRL) is innervated by the radial nerve proper, proximal to the PIN branch, while the ECU (innervated by the PIN) is paralyzed. The lateral antebrachial cutaneous nerve (LABCN) is the most commonly injured sensory nerve in this approach, but it would cause sensory deficits in the lateral forearm, not motor weakness. Median and AIN injuries would affect volar forearm flexors.

Question 2832

Topic: 9. Shoulder and Elbow

A 62-year-old male is scheduled for a total shoulder arthroplasty for primary glenohumeral osteoarthritis. Preoperative axial CT scan reveals a biconcave glenoid with significant retroversion and posterior subluxation of the humeral head. According to the Walch classification of glenoid morphology, what type of glenoid is present?

. Type A1
. Type A2
. Type B1
. Type B2
. Type C

Correct Answer & Explanation

. Type B2

Explanation

Correct Answer: DThe Walch classification describes glenoid morphology in primary glenohumeral osteoarthritis.- Type A glenoids have a centered humeral head (A1 = minor erosion, A2 = major central erosion).- Type B glenoids have posterior subluxation of the humeral head. B1 features posterior subluxation without significant bony erosion. B2 is the classic "biconcave" glenoid with posterior wear, retroversion, and posterior subluxation.- Type C glenoids are dysplastic with severe retroversion (>25 degrees) regardless of humeral head subluxation.The description of a biconcave glenoid with posterior subluxation perfectly matches a Walch Type B2 glenoid. Addressing the retroversion and posterior wear in a B2 glenoid is a critical and challenging aspect of total shoulder arthroplasty to prevent early component loosening.

Question 2833

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old male undergoes a reverse total shoulder arthroplasty (rTSA) for severe rotator cuff tear arthropathy. To minimize the risk of scapular notching—a complication specific to the altered biomechanics of this implant—the surgeon plans the glenosphere positioning carefully. In addition to placing the glenosphere with 10 to 20 degrees of inferior tilt, which of the following biomechanical alterations is most effective in reducing the incidence of this complication?

. Superior translation of the glenosphere
. Medialization of the center of rotation
. Lateralization of the center of rotation
. Increased retroversion of the glenosphere
. Decreased neck-shaft angle of the humeral component

Correct Answer & Explanation

. Lateralization of the center of rotation

Explanation

Correct Answer: C (Lateralization of the center of rotation)Scapular notching in rTSA occurs when the medial aspect of the humeral polyethylene liner impinges against the inferior scapular neck during arm adduction. The traditional Grammont-style rTSA inherently medializes and inferiorizes the center of rotation to maximize the deltoid moment arm. However, this profound medialization brings the humeral component closer to the scapular neck, increasing the risk of notching. To combat this, modern techniques utilize lateralization of the center of rotation (either via a bony increased-offset [BIO-RSA] or a metallic lateralized glenosphere/baseplate). Lateralizing the glenosphere pushes the humerus away from the scapula, increasing the impingement-free range of motion in adduction. Superior translation exacerbates notching. Medialization is the primary cause of notching. Retroversion affects anterior/posterior stability, not inferior notching. Decreasing the neck-shaft angle (e.g., from 155 to 135 degrees) actually helps reduce notching, but lateralization of the glenosphere is a primary glenoid-sided strategy.

Question 2834

Topic: Elbow & Forearm

A 35-year-old male presents with recurrent elbow clicking and a sensation of the elbow "giving out" when pushing himself up from a chair. A pivot-shift test of the elbow is positive. The primary ligamentous restraint that is deficient in this patient originates from the lateral epicondyle and inserts onto which of the following anatomic structures?

. Radial neck
. Annular ligament
. Supinator crest of the ulna
. Coronoid process of the ulna
. Olecranon process

Correct Answer & Explanation

. Supinator crest of the ulna

Explanation

Correct Answer: C (Supinator crest of the ulna)The patient's clinical presentation (clicking, giving way when pushing off a chair) and a positive pivot-shift test are pathognomonic for posterolateral rotatory instability (PLRI) of the elbow. PLRI is caused by insufficiency of the lateral ulnar collateral ligament (LUCL). The LUCL is the primary restraint to varus and posterolateral rotatory forces. Anatomically, the LUCL originates from the lateral epicondyle of the humerus, blends with the annular ligament, and inserts onto the supinator crest of the proximal ulna. It does not insert on the radial neck, coronoid process (which is the insertion for the anterior bundle of the MUCL), or the olecranon.

Question 2835

Topic: 9. Shoulder and Elbow
A 45-year-old male falls from a ladder, sustaining a "Terrible Triad" injury of the elbow. Intraoperatively, after prosthetic replacement of a highly comminuted radial head and robust repair of the lateral ulnar collateral ligament (LUCL) to the lateral epicondyle, the elbow remains unstable and readily subluxates posteriorly in extension. The coronoid fracture is a small tip avulsion (Regan-Morrey Type I). What is the most appropriate next step in the surgical algorithm to restore stability?
. Repair the medial ulnar collateral ligament (MUCL)
. Fix the coronoid tip fracture with a headless compression screw
. Apply a hinged external fixator
. Perform a triceps fascial advancement
. Resect the remaining coronoid process

Correct Answer & Explanation

. Repair the medial ulnar collateral ligament (MUCL)

Explanation

The standard surgical algorithm for a Terrible Triad injury (elbow dislocation, radial head fracture, coronoid fracture) proceeds from deep to superficial and lateral to medial. The steps are: 1) Address the coronoid (fix if Type II/III; Type I tip avulsions are often anterior capsule avulsions and can be left or suture-lassoed if unstable), 2) Address the radial head (fix or replace), 3) Repair the lateral collateral ligament complex (LUCL). After these steps, the elbow is taken through a range of motion to assess stability. If the elbow remains unstable in extension (meaning it subluxates or dislocates), the next step in the algorithm is to address the medial side by repairing the medial ulnar collateral ligament (MUCL). If the elbow remains unstable even after MUCL repair, a hinged external fixator is applied. Fixing a Type I coronoid tip with a screw is technically difficult and often unnecessary if the capsule is repaired. Resecting the coronoid would worsen instability.

Question 2836

Topic: 9. Shoulder and Elbow
A 52-year-old female with type 1 diabetes presents with insidious onset of severe shoulder stiffness. Examination shows a 50% reduction in both active and passive external rotation with the arm resting at her side, compared to the contralateral shoulder. Histological evaluation of the primary anatomical region responsible for this specific motion deficit would most likely show fibroblastic proliferation and dense type III collagen deposition in which of the following structures?
. Posterior band of the inferior glenohumeral ligament
. Coracohumeral ligament and superior glenohumeral ligament
. Middle glenohumeral ligament
. Acromioclavicular joint capsule
. Subacromial bursa

Correct Answer & Explanation

. Coracohumeral ligament and superior glenohumeral ligament

Explanation

This patient has classic adhesive capsulitis (frozen shoulder), which is strongly associated with diabetes. The hallmark physical exam finding is a significant loss of passive external rotation with the arm at the side. The anatomical structures that primarily restrict external rotation when the arm is adducted (at the side) are the components of the rotator interval: the coracohumeral ligament (CHL) and the superior glenohumeral ligament (SGHL). Pathologically, adhesive capsulitis involves profound fibroblastic proliferation, inflammation, and contracture of these specific structures, leading to the characteristic clinical deficit. The middle glenohumeral ligament restricts external rotation at 45 degrees of abduction. The inferior glenohumeral ligament (anterior band) restricts external rotation at 90 degrees of abduction. The posterior band of the IGHL restricts internal rotation.

Question 2837

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female presents with progressive shoulder pain two years after undergoing a reverse total shoulder arthroplasty (rTSA) for rotator cuff tear arthropathy. Radiographs reveal significant erosion of the inferior scapular neck, consistent with severe scapular notching. Which of the following intraoperative technical errors during the initial placement of the glenosphere most likely contributed to this complication?

. Superior tilt of the glenosphere.
. Excessive inferior tilt of the glenosphere.
. 10 degrees of retroversion of the glenosphere.
. 10 degrees of anteversion of the humeral component.
. Use of a larger diameter glenosphere.

Correct Answer & Explanation

. Superior tilt of the glenosphere.

Explanation

Correct Answer: Superior tilt of the glenosphere.Scapular notching is a well-recognized complication unique to reverse total shoulder arthroplasty (rTSA). It occurs due to mechanical impingement of the medial edge of the humeral polyethylene liner against the inferior scapular neck during arm adduction and internal rotation. To minimize this risk, biomechanical principles dictate that the glenosphere should be placed with a neutral version and approximately 10 to 20 degrees of inferior tilt. Superior tilt of the glenosphere moves the center of rotation superiorly, decreasing the clearance between the humeral component and the scapular pillar, thereby significantly increasing the risk and severity of scapular notching. Using a larger diameter glenosphere or lateralizing the center of rotation actually helpsdecreasethe risk of notching by increasing the impingement-free range of motion.

Question 2838

Topic: Elbow & Forearm

An 8-year-old male gymnast presents with a 3-month history of insidious onset lateral right elbow pain, exacerbated by weight-bearing activities. Radiographs demonstrate diffuse sclerosis, fragmentation, and flattening of the entire capitellar ossification center. There are no loose bodies identified on imaging. Based on the most likely diagnosis, what is the expected natural history and appropriate management?

. Progression to loose body formation requiring arthroscopic debridement.
. Spontaneous resolution and reossification with rest and activity modification.
. High risk of premature physeal closure requiring percutaneous pinning.
. Development of posterolateral rotatory instability requiring ligament reconstruction.
. Obligate progression to severe radiocapitellar osteoarthritis by early adulthood.

Correct Answer & Explanation

. Spontaneous resolution and reossification with rest and activity modification.

Explanation

Correct Answer: Spontaneous resolution and reossification with rest and activity modification.This clinical presentation is classic for Panner's disease, an osteochondrosis of the capitellum. It typically affects children between 5 and 10 years of age, often those involved in repetitive overhead or upper extremity weight-bearing sports (like gymnastics or baseball). Radiographically, it presents as diffuse sclerosis and fragmentation of the capitellar ossification center. Crucially, Panner's disease is a self-limiting condition of avascular necrosis followed by revascularization and reossification. The natural history is excellent, with spontaneous resolution expected over several months to a few years. Treatment consists of rest, activity modification, and symptomatic management. This must be differentiated from osteochondritis dissecans (OCD) of the capitellum, which typically occurs in older children/adolescents (12-16 years), presents with focal lesions, and carries a higher risk of loose body formation and long-term arthritic changes.

Question 2839

Topic: Elbow & Forearm

A 45-year-old male falls from a ladder, sustaining a 'Terrible Triad' injury of the elbow. He is taken to the operating room for surgical reconstruction. The surgeon first addresses the coronoid fracture with a suture lasso technique, followed by replacement of the highly comminuted radial head with a metallic prosthesis. Upon testing, the elbow remains unstable and readily subluxates when extended in supination. Which of the following is the most appropriate next step in the surgical algorithm?

. Repair the medial ulnar collateral ligament (MUCL).
. Repair the lateral ulnar collateral ligament (LUCL) complex.
. Apply a hinged dynamic external fixator.
. Perform an olecranon osteotomy to access the posterior capsule.
. Upsize the radial head implant to increase radiocapitellar tension.

Correct Answer & Explanation

. Repair the lateral ulnar collateral ligament (LUCL) complex.

Explanation

Correct Answer: Repair the lateral ulnar collateral ligament (LUCL) complex.The 'Terrible Triad' of the elbow consists of a posterior elbow dislocation, a radial head fracture, and a coronoid fracture. The standard surgical algorithm for restoring stability proceeds from deep to superficial, typically starting with the coronoid (anterior stabilization), followed by the radial head (lateral column bony stabilization). After these bony structures are addressed, the lateral collateral ligament complex (specifically the LUCL), which is invariably torn in this injury pattern (usually avulsed from the lateral epicondyle), must be repaired. If the elbow remains unstable in extension and supination after coronoid and radial head fixation, the LUCL is the primary deficient restraint. Repairing the MUCL is only indicated if the elbow remains unstable in extension andpronationafter the coronoid, radial head, and LUCL have all been securely fixed. A hinged external fixator is a salvage option if stability cannot be achieved after all ligamentous repairs. Upsizing the radial head can lead to overstuffing, causing capitellar wear and stiffness.

Question 2840

Topic: Shoulder Arthroplasty & Arthritis

A 68-year-old female undergoes an anatomic total shoulder arthroplasty. Six weeks postoperatively, she presents with increased passive external rotation compared to her intraoperative assessment, profound weakness in active internal rotation, and a positive abdominal press test. Which of the following is the most likely cause of her clinical presentation?

. Axillary nerve neuropraxia
. Subscapularis tendon failure
. Glenoid component loosening
. Anterior capsular contracture
. Secondary rotator cuff tear arthropathy

Correct Answer & Explanation

. Subscapularis tendon failure

Explanation

Subscapularis failure after anatomic TSA typically presents with increased passive external rotation, weak internal rotation, and positive lift-off or belly-press tests. It is a recognized complication related to the takedown and repair of the tendon during the standard deltopectoral approach.

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