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9. Shoulder and Elbow MCQs

Practice Set 172 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 3421

Topic: 9. Shoulder and Elbow

A macrosomic newborn presents with an adducted, internally rotated shoulder, extended elbow, and pronated forearm ("waiter's tip" posture). Grasp reflex is intact. Which nerve roots are primarily involved in this injury?

. C5 and C6
. C7, C8, and T1
. C5, C6, and C7
. C8 and T1
. C5 through T1

Correct Answer & Explanation

. C5 and C6

Explanation

Erb-Duchenne palsy is an upper trunk brachial plexus injury involving the C5 and C6 nerve roots. It presents with the classic "waiter's tip" posture due to paralysis of the shoulder abductors, elbow flexors, and forearm supinators, while preserving hand function.

Question 3422

Topic: 9. Shoulder and Elbow

A 68-year-old male presents with severe right shoulder pain and an inability to actively elevate his arm beyond 45 degrees, despite full passive range of motion. MRI demonstrates massive, retracted tears of the supraspinatus and infraspinatus with grade IV fatty infiltration, and advanced glenohumeral osteoarthritis. The subscapularis and teres minor are intact. What is the most appropriate surgical intervention?

. Arthroscopic rotator cuff repair
. Latissimus dorsi tendon transfer
. Anatomic total shoulder arthroplasty
. Reverse total shoulder arthroplasty
. Shoulder arthrodesis

Correct Answer & Explanation

. Reverse total shoulder arthroplasty

Explanation

The patient has cuff tear arthropathy with pseudoparalysis (inability to actively elevate the arm above 90 degrees in the presence of full passive ROM) and advanced fatty infiltration of the cuff muscles, making them irreparable. Reverse total shoulder arthroplasty (RTSA) is the treatment of choice. It moves the center of rotation medially and inferiorly, allowing the deltoid to act as the primary elevator of the arm. Anatomic TSA is contraindicated due to the lack of a functioning rotator cuff, which would lead to 'rocking horse' loosening of the glenoid component.

Question 3423

Topic: Elbow & Forearm

A 32-year-old male sustains a midshaft humerus fracture resulting in a complete radial nerve palsy. After 1 year, there is no clinical or electromyographic (EMG) evidence of recovery. A tendon transfer is planned to restore wrist extension. Which of the following is the most standard donor-recipient tendon transfer for this purpose?

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

Correct Answer & Explanation

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

Explanation

The pronator teres (PT) to extensor carpi radialis brevis (ECRB) transfer is the standard and most mechanically sound choice to restore wrist extension in radial nerve palsy. The ECRB is preferred over the ECRL because its central location on the carpus provides balanced wrist extension without inducing unwanted radial deviation.

Question 3424

Topic: 9. Shoulder and Elbow

A 72-year-old female presents with severe right shoulder pain and an inability to actively elevate her arm above 60 degrees. Radiographs show superior migration of the humeral head with severe glenohumeral osteoarthritis (Hamada Grade 4). An MRI confirms a massive, retracted, irreparable rotator cuff tear. What is the most appropriate surgical treatment?

. Arthroscopic superior capsular reconstruction
. Latissimus dorsi tendon transfer
. Anatomic total shoulder arthroplasty
. Reverse total shoulder arthroplasty
. Shoulder hemiarthroplasty

Correct Answer & Explanation

. Reverse total shoulder arthroplasty

Explanation

The patient has severe rotator cuff tear arthropathy (massive irreparable tear, glenohumeral arthritis, superior humeral head migration) and pseudoparalysis. Reverse total shoulder arthroplasty (RTSA) is the treatment of choice. By medializing and distalizing the center of rotation, RTSA increases the lever arm of the deltoid, allowing it to compensate for the deficient rotator cuff and restore active elevation. Anatomic TSA is contraindicated due to the 'rocking horse' phenomenon, which leads to early glenoid component loosening.

Question 3425

Topic: 9. Shoulder and Elbow

A 35-year-old male sustains a fall onto an outstretched hand, resulting in a terrible triad injury of the elbow. During surgical management, after repair of the coronoid fracture, fixation of the radial head, and repair of the lateral ulnar collateral ligament (LUCL), the elbow demonstrates persistent subluxation when extended past 30 degrees. What is the most appropriate next step in management?

. Fascial arthroplasty of the radiocapitellar joint
. Repair of the medial collateral ligament (MCL)
. Immediate radial head excision
. Transarticular pin fixation for 4 weeks
. Isolated repair of the anterior joint capsule

Correct Answer & Explanation

. Repair of the medial collateral ligament (MCL)

Explanation

The standard algorithm for treating a terrible triad injury involves repairing structures from deep to superficial (or inside-out), typically addressing the coronoid, then radial head, then LUCL. If the elbow remains unstable in extension after these lateral structures and anterior structures are stabilized, the medial collateral ligament (MCL) should be repaired or a hinged external fixator applied.

Question 3426

Topic: 9. Shoulder and Elbow

Which of the following best describes the biomechanical advantage achieved by a reverse total shoulder arthroplasty in a patient with rotator cuff tear arthropathy?

. Lateralization of the center of rotation, which increases the deltoid moment arm
. Medialization and inferiorization of the center of rotation, which increases the deltoid moment arm and tension
. Superior migration of the center of rotation, thereby replacing the function of the supraspinatus
. Medialization of the center of rotation, which decreases the deltoid lever arm to reduce shear forces
. Anatomic restoration of the center of rotation to optimize intact subscapularis function

Correct Answer & Explanation

. Medialization and inferiorization of the center of rotation, which increases the deltoid moment arm and tension

Explanation

A reverse total shoulder arthroplasty medializes and inferiorizes the center of rotation of the glenohumeral joint compared to native anatomy. This recruits more of the deltoid muscle fibers and significantly increases the moment arm and resting tension of the deltoid, allowing it to elevate the arm without a functioning rotator cuff.

Question 3427

Topic: Elbow & Forearm

A 42-year-old male undergoes surgical repair of a distal biceps tendon rupture via a single anterior incision. Post-operatively, he exhibits an inability to actively extend his metacarpophalangeal (MCP) joints and thumb interphalangeal joint, though tenodesis effect is intact. His wrist extension demonstrates radial deviation. Sensation is fully intact. Which nerve was most likely injured during the procedure?

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

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

The posterior interosseous nerve (PIN) is at risk during an anterior single-incision approach to the distal biceps, particularly with overzealous lateral retraction. A PIN palsy results in loss of active extension of the digits and thumb. Wrist extension results in radial deviation because the extensor carpi radialis longus (innervated by the radial nerve proper) remains functional while the extensor carpi ulnaris (PIN innervated) is paralyzed. Sensation remains intact.

Question 3428

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 3429

Topic: Elbow & Forearm

A 45-year-old male undergoes surgical repair of a distal biceps tendon rupture using a single-anterior-incision technique with cortical button fixation. Postoperatively, he complains of numbness over the lateral aspect of his forearm. Injury to which of the following nerves is the most common complication of this specific surgical approach?

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

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve

Explanation

The lateral antebrachial cutaneous nerve (LABC) is highly susceptible to traction or iatrogenic injury during the single-anterior-incision approach to the distal biceps. In contrast, posterior interosseous nerve (PIN) injury or radioulnar synostosis is classically more associated with the two-incision technique.

Question 3430

Topic: 9. Shoulder and Elbow

In a patient undergoing a Reverse Total Shoulder Arthroplasty (RTSA) for cuff tear arthropathy, how does the prosthesis alter the normal shoulder biomechanics to compensate for the deficient rotator cuff?

. Lateralizes and superiorly translates the center of rotation
. Medializes and distalizes the center of rotation
. Lateralizes and distalizes the center of rotation
. Medializes and superiorly translates the center of rotation
. Maintains the anatomic center of rotation while increasing constraint

Correct Answer & Explanation

. Medializes and distalizes the center of rotation

Explanation

RTSA medializes and distalizes the center of rotation of the glenohumeral joint. This significantly increases the moment arm and resting tension of the deltoid muscle, allowing it to elevate the arm without a functioning rotator cuff.

Question 3431

Topic: 9. Shoulder and Elbow

A 65-year-old female presents with pseudoparalysis of her right shoulder, preserved passive motion, and severe glenohumeral arthritis. MRI shows a massive, retracted, and fatty-infiltrated rotator cuff tear. What is the most appropriate surgical treatment?

. Arthroscopic superior capsule reconstruction
. Reverse total shoulder arthroplasty
. Anatomic total shoulder arthroplasty
. Latissimus dorsi tendon transfer
. Arthroscopic rotator cuff repair

Correct Answer & Explanation

. Reverse total shoulder arthroplasty

Explanation

Reverse total shoulder arthroplasty is the gold standard for rotator cuff tear arthropathy with pseudoparalysis. It restores overhead elevation by utilizing the deltoid muscle and medializing the center of rotation. Anatomic TSA is contraindicated due to the deficient rotator cuff causing eccentric glenoid wear.

Question 3432

Topic: Elbow & Forearm

A 45-year-old male falls from a ladder and sustains an isolated proximal ulna shaft fracture with an associated anterior dislocation of the radial head (Bado Type I Monteggia injury). During surgery, the ulna is anatomically reduced and plated, but the radial head remains persistently dislocated. What is the most likely interposing structure preventing reduction?

. Median nerve
. Biceps brachii tendon
. Annular ligament
. Brachialis muscle
. Lateral ulnar collateral ligament

Correct Answer & Explanation

. Annular ligament

Explanation

In Monteggia fractures, anatomic restoration of ulnar length and alignment typically spontaneously reduces the radial head. If the radial head fails to reduce, the annular ligament or joint capsule is the most common interposing structure, requiring open reduction.

Question 3433

Topic: 9. Shoulder and Elbow

What is the primary restraint to valgus stress at the elbow during 30 to 120 degrees of flexion?

. Radial head
. Posterior bundle of the medial ulnar collateral ligament
. Anterior bundle of the medial ulnar collateral ligament
. Lateral ulnar collateral ligament
. Common flexor tendon origin

Correct Answer & Explanation

. Anterior bundle of the medial ulnar collateral ligament

Explanation

The anterior bundle of the medial ulnar collateral ligament (MUCL) is the primary restraint to valgus stress at the elbow throughout the functional arc of flexion. The radial head acts as an important secondary bony restraint.

Question 3434

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 3435

Topic: Elbow & Forearm

A 9-year-old male gymnast presents with lateral elbow pain and stiffness. Radiographs show sclerosis and fragmentation of the capitellum with an open proximal radial physis. An MRI confirms diffuse high T2 signal in the capitellum without a discrete osteochondral fragment. What is the most appropriate management?

. Arthroscopic drilling of the capitellum
. Open osteochondral autograft transfer
. Casting for 6 weeks followed by gradual return to play
. Rest, cessation of gymnastics, and symptomatic treatment
. Arthroscopic fragment excision and loose body removal

Correct Answer & Explanation

. Rest, cessation of gymnastics, and symptomatic treatment

Explanation

The clinical presentation (age <10 years, typical radiographic findings without a discrete loose body) is classic for Panner's disease (osteochondrosis of the capitellum). Unlike osteochondritis dissecans (OCD) of the capitellum, which typically occurs in older adolescents and often requires surgery, Panner's disease is self-limiting. The standard treatment is conservative, consisting of rest and avoidance of inciting activities until symptoms resolve.

Question 3436

Topic: Shoulder Pathology

A 21-year-old collegiate pitcher is diagnosed with SICK scapula syndrome (Scapular malposition, Inferior medial border prominence, Coracoid pain, and dysKinesis). Examination shows significant anterior tilt of the scapula. Tightness of which of the following muscular structures is the primary driver of this anterior tilt?

. Serratus anterior
. Lower trapezius
. Pectoralis minor
. Levator scapulae
. Rhomboid major

Correct Answer & Explanation

. Pectoralis minor

Explanation

SICK scapula syndrome typically features an anteriorly tilted and protracted scapula. This is classically driven by tightness or contracture of the pectoralis minor (which inserts on the coracoid process, pulling the scapula anteriorly and inferiorly) combined with weakness of the primary scapular stabilizers, notably the lower trapezius and serratus anterior.

Question 3437

Topic: Elbow & Forearm

A 40-year-old recreational weightlifter undergoes surgical repair of an acute distal biceps tendon rupture via a single-incision anterior approach. Post-operatively, he complains of numbness and tingling along the lateral aspect of his forearm. Which nerve is most likely injured?

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

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve (LABCN)

Explanation

The lateral antebrachial cutaneous nerve (LABCN), which is the terminal sensory branch of the musculocutaneous nerve, exits deep to the biceps and lies in the subcutaneous tissue of the lateral forearm. Due to necessary lateral retraction during a single-incision anterior approach for distal biceps repair, the LABCN is the most commonly injured nerve, leading to lateral forearm paresthesias.

Question 3438

Topic: 9. Shoulder and Elbow

A 22-year-old elite baseball pitcher presents with posterior shoulder pain and a significant loss of internal rotation (GIRD). Physical examination reveals a glenohumeral internal rotation deficit of 25 degrees compared to the contralateral side. Pathologic contracture of the posterior band of the inferior glenohumeral ligament (IGHL) alters glenohumeral kinematics during the late cocking phase of throwing. In which direction does the glenohumeral contact point abnormally shift as a result of this contracture?

. Posteroinferiorly
. Posterosuperiorly
. Anteroinferiorly
. Anterosuperiorly
. Directly superiorly

Correct Answer & Explanation

. Posterosuperiorly

Explanation

In the throwing athlete, repeated microtrauma can lead to contracture of the posterior capsule, specifically the posterior band of the IGHL. This contracture tethering forces the humeral head to shift posterosuperiorly during the late cocking phase of throwing (abduction and maximal external rotation). This posterosuperior shift increases contact between the greater tuberosity and the posterosuperior glenoid, leading to internal impingement and 'peel-back' superior labrum anterior-posterior (SLAP) tears.

Question 3439

Topic: 9. Shoulder and Elbow

A 21-year-old collegiate baseball pitcher undergoes ulnar collateral ligament (UCL) reconstruction utilizing the docking technique. Prior to surgery, he reported medial elbow pain during the late cocking and early acceleration phases of throwing. Which specific bundle of the UCL was most likely incompetent and reconstructed?

. Posterior bundle
. Transverse bundle
. Anterior bundle
. Lateral ulnar collateral ligament
. Annular ligament

Correct Answer & Explanation

. Anterior bundle

Explanation

The anterior bundle of the ulnar collateral ligament is the primary static restraint to valgus stress at the elbow, particularly during the late cocking and early acceleration phases of throwing. Modern UCL reconstructions aim to restore this specific functional bundle.

Question 3440

Topic: 9. Shoulder and Elbow

A 62-year-old male laborer presents with a massive, irreparable posterosuperior rotator cuff tear without glenohumeral arthritis (Hamada Grade 1). A lower trapezius tendon transfer is planned to restore external rotation. Which nerve provides the primary motor innervation to the muscle being transferred?

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

Correct Answer & Explanation

. Spinal accessory nerve

Explanation

The lower trapezius is innervated by the spinal accessory nerve (Cranial Nerve XI). It is increasingly utilized for tendon transfers in irreparable posterosuperior rotator cuff tears due to its favorable line of pull that mimics the infraspinatus.

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