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 2861
Topic: 9. Shoulder and Elbow
What is the typical mechanism of injury for a traumatic anterior shoulder dislocation?
Correct Answer & Explanation
. Fall on an outstretched arm in abduction and external rotation
Explanation
The classic mechanism for a traumatic anterior shoulder dislocation is an indirect force, such as a fall on an outstretched arm, which drives the humeral head anteriorly and inferiorly, especially when the arm is in abduction and external rotation. Direct blows to the posterior shoulder, seizures/electrocution are mechanisms for posterior dislocation. Direct fall onto the adducted arm is less specific and could lead to other injuries. Repeated heavy lifting is more associated with overuse injuries or rotator cuff pathology.
Question 2862
Topic: 9. Shoulder and Elbow
A patient is unable to initiate shoulder abduction against gravity. Which nerve is MOST likely injured?
Correct Answer & Explanation
. Suprascapular nerve
Explanation
The supraspinatus muscle, primarily innervated by the suprascapular nerve, is responsible for initiating the first 15-30 degrees of shoulder abduction. While the deltoid (axillary nerve) takes over for further abduction, the inability toinitiateabduction strongly points to the supraspinatus/suprascapular nerve. Axillary nerve injury would cause deltoid weakness in later abduction. Long thoracic affects serratus anterior. Median and radial nerves are distal to the shoulder.
Question 2863
Topic: 9. Shoulder and Elbow
A patient with known Ehlers-Danlos Syndrome presents with recurrent, atraumatic shoulder dislocations. Which type of instability is MOST likely in this patient?
Correct Answer & Explanation
. Atraumatic multidirectional instability
Explanation
Ehlers-Danlos Syndrome is a connective tissue disorder characterized by generalized ligamentous laxity. Patients with such systemic laxity are prone to atraumatic, recurrent dislocations in multiple directions, classifying it as atraumatic multidirectional instability. Traumatic unidirectional instabilities are typically associated with specific injury mechanisms. Voluntary dislocation can be part of MDI but MDI describes the underlying instability.
Question 2864
Topic: 9. Shoulder and Elbow
Which of the following signs on physical exam is most indicative of a pectoralis major rupture?
Correct Answer & Explanation
. Loss of the normal axillary fold contour and weakness in internal rotation and adduction
Explanation
Pectoralis major rupture, especially of the sternal head, leads to a loss of the normal axillary fold contour and significant weakness in shoulder adduction and internal rotation. Option B describes anterior dislocation. Options C and D relate to rotator cuff or nerve injuries, respectively. Option E is non-specific.
Question 2865
Topic: 9. Shoulder and Elbow
When assessing a patient who has sustained a fall onto the lateral aspect of their shoulder, leading to a suspected dislocated shoulder, which of the following anatomical landmarks should be carefully palpated for tenderness and deformity, specifically ruling out an AC joint injury?
Correct Answer & Explanation
. Acromion and distal clavicle
Explanation
A fall onto the lateral aspect of the shoulder can cause an AC joint separation, which must be differentiated from or recognized in addition to a glenohumeral dislocation. Palpating the acromion and distal clavicle for tenderness, deformity, and assessing the step-off at the AC joint is crucial for diagnosing an AC injury. The other landmarks relate more to the glenohumeral joint or specific tendons.
Question 2866
Topic: Shoulder Pathology
A 24-year-old athlete sustains a traction injury to his shoulder and subsequently presents with medial scapular winging that is accentuated when pushing against a wall. The affected nerve is formed by the confluence of which of the following nerve roots?
Correct Answer & Explanation
. C5, C6, and C7
Explanation
Medial scapular winging is caused by paralysis of the serratus anterior muscle, which is innervated by the long thoracic nerve. The long thoracic nerve arises directly from the ventral rami of the C5, C6, and C7 nerve roots.
Question 2867
Topic: 9. Shoulder and Elbow
A 58-year-old active male presents with chronic right shoulder pain and weakness, severely limiting his overhead activities and recreation. Physical examination reveals significant weakness with external rotation and abduction, a positive drop arm test, and significant atrophy of the supraspinatus and infraspinatus. MRI shows a massive, retracted rotator cuff tear with significant fatty infiltration of the rotator cuff muscles (Goutallier Stage 3-4). He has failed extensive non-operative management. What is the most appropriate surgical option for this patient?
Correct Answer & Explanation
. Reverse total shoulder arthroplasty (RTSA).
Explanation
This patient has a massive, irreparable rotator cuff tear with significant fatty infiltration (Goutallier Stage 3-4), which indicates poor tissue quality and a low likelihood of successful primary repair. Furthermore, the chronic pain, weakness, and functional limitation suggest rotator cuff arthropathy (or an impending one), especially with superior migration of the humeral head. In such scenarios, arthroscopic rotator cuff repair (A) is unlikely to succeed. Subacromial decompression (B) is inadequate for a massive tear. Latissimus dorsi tendon transfer (C) can be considered for younger, active patients with intact deltoid and no glenohumeral arthritis, but the extensive fatty infiltration and age might make this less predictable for restoring overhead function fully. Reverse total shoulder arthroplasty (RTSA) (D) is specifically designed to address rotator cuff deficiency by shifting the center of rotation and utilizing the deltoid muscle for elevation, providing reliable pain relief and functional improvement in patients with irreparable cuff tears and cuff tear arthropathy. Total shoulder arthroplasty (E) is contraindicated in the presence of an irreparable rotator cuff tear due to rapid loosening of the glenoid component.
Question 2868
Topic: 9. Shoulder and Elbow
A 45-year-old male sustains a supraclavicular brachial plexus injury (C5-T1 avulsion) following a motorcycle accident, resulting in complete flail arm. Six months post-injury, he has no motor or sensory return. What is the most appropriate reconstructive strategy to achieve optimal functional outcome?
Correct Answer & Explanation
. Nerve transfers (e.g., intercostal nerves, accessory nerve) to restore elbow flexion and shoulder abduction.
Explanation
For a complete flail arm due to supraclavicular brachial plexus avulsion where 6 months have passed without any motor or sensory return, the nerve roots are typically avulsed from the spinal cord, making direct nerve repair (Option B) impossible. Neurolysis is for compression, not avulsion. Nerve transfers, such as using intercostal nerves, the contralateral C7 nerve, or the spinal accessory nerve, are the primary reconstructive option within the first 6-12 months post-injury (the 'golden period' for nerve surgery). The goal is to reinnervate critical muscles, especially those responsible for elbow flexion (biceps) and shoulder abduction (deltoid), as these significantly improve upper limb function. Tendon transfers (Option A) are secondary procedures, usually considered after nerve reconstruction fails or for more distal deficits, or if more time has passed. Free functional muscle transfer (Option E) can be used, but typically after nerve transfers if limited donors or insufficient recovery. Arthrodesis (Option D) is a salvage procedure for a painful flail joint, not initial functional reconstruction.
Question 2869
Topic: 9. Shoulder and Elbow
A 75-year-old female presents with severe, chronic shoulder pain, pseudoparalysis, and inability to abduct her arm beyond 45 degrees. Radiographs show superior migration of the humeral head, severe glenohumeral arthritis, and a massive, irreparable rotator cuff tear. She has failed conservative management. What is the most appropriate surgical intervention?
Correct Answer & Explanation
. Reverse total shoulder arthroplasty (rTSA)
Explanation
The constellation of symptoms (severe shoulder pain, pseudoparalysis, inability to abduct, superior humeral head migration, severe glenohumeral arthritis, and a massive irreparable rotator cuff tear) is classic for rotator cuff tear arthropathy. In such cases, a reverse total shoulder arthroplasty (rTSA) is the gold standard treatment. The rTSA medializes and distally positions the center of rotation, increasing the deltoid moment arm and allowing it to become the primary elevator and abductor of the arm, thereby restoring active elevation in the absence of a functional rotator cuff. Hemiarthroplasty and TSA rely on an intact rotator cuff. Rotator cuff repair is not possible for an irreparable tear. Arthrodesis is a salvage procedure with significant functional limitations.
Question 2870
Topic: 9. Shoulder and Elbow
A 72-year-old patient presents with chronic shoulder pain, inability to actively elevate the arm above 60 degrees (pseudoparalysis), and profound weakness following a massive, irreparable rotator cuff tear. Imaging confirms significant superior migration of the humeral head and glenoid erosion. The deltoid muscle is intact and functional. What is the primary indication for performing a Reverse Total Shoulder Arthroplasty (RTSA) in this patient?
Correct Answer & Explanation
. Restoration of active shoulder elevation in the setting of pseudoparalysis.
Explanation
The primary unique indication for Reverse Total Shoulder Arthroplasty (RTSA) in a patient with a massive irreparable rotator cuff tear and pseudoparalysis is the restoration of active shoulder elevation and function. RTSA alters the shoulder's center of rotation, medializing it and distalizing the humerus, which increases the deltoid's lever arm and effectively converts it into the primary elevator of the arm, thereby addressing the pseudoparalysis. While pain relief is also achieved, the functional improvement in active motion is the defining feature of RTSA for this specific condition.
Question 2871
Topic: 9. Shoulder and Elbow
A 48-year-old factory worker presents with a 6-month history of progressive pain and weakness in his right shoulder. He reports difficulty lifting his arm overhead and pain with internal rotation. Physical examination reveals significant atrophy of the infraspinatus and supraspinatus muscles, weak external rotation, and a positive drop-arm test. MRI shows a massive, irreparable rotator cuff tear involving the supraspinatus and infraspinatus, with significant fatty infiltration and muscle retraction. He has failed extensive non-operative treatment. What is the most appropriate surgical option for this patient to improve function and reduce pain?
Correct Answer & Explanation
. Reverse total shoulder arthroplasty (rTSA).
Explanation
This patient presents with a massive, irreparable rotator cuff tear, characterized by significant atrophy, fatty infiltration, and retraction, leading to profound weakness and functional deficit. Given the failure of conservative treatment and the severe, irreparable nature of the tear in a relatively active patient, a reverse total shoulder arthroplasty (rTSA) is often the most appropriate surgical option. rTSA works by medializing the center of rotation and increasing the deltoid lever arm, allowing the deltoid muscle to substitute for the lost rotator cuff function, thereby improving elevation and external rotation. Direct repair (Option A) is not feasible for an irreparable tear. Subacromial decompression (Option B) alone is insufficient for a massive tear. Latissimus dorsi transfer (Option C) is an option for younger, active patients with irreparable posterosuperior tears, but rTSA typically provides more predictable and robust pain relief and functional improvement in this age group, especially if there is significant glenohumeral arthritis (cuff tear arthropathy) which is not explicitly mentioned but implied by chronic irreparable tear. Biceps tenodesis (Option E) addresses biceps pain but not the overall rotator cuff deficiency or functional loss.
Question 2872
Topic: Elbow & Forearm
A 50-year-old active female presents with chronic lateral elbow pain exacerbated by gripping and lifting. She has failed 6 months of conservative treatment including physical therapy, bracing, and corticosteroid injections. Physical examination reveals tenderness over the common extensor origin, pain with resisted wrist extension, and no neurological deficits. MRI shows tendinosis and partial tearing of the extensor carpi radialis brevis (ECRB) origin. What is the most appropriate surgical intervention?
Correct Answer & Explanation
. Open release of the common extensor origin with debridement of the ECRB and decortication.
Explanation
This patient presents with classic features of lateral epicondylitis (tennis elbow) that has failed conservative management. The pathology primarily involves tendinosis and partial tearing of the extensor carpi radialis brevis (ECRB) at its origin. The most appropriate surgical intervention is an open release of the common extensor origin, with debridement of the pathologic ECRB tissue and decortication of the lateral epicondyle to promote healing. This is a well-established and effective procedure. Arthroscopic debridement of the capitellum (Option B) is not the primary pathology. Ulnar nerve transposition (Option C) and radial nerve decompression (Option D) are for nerve entrapment syndromes, not tendinopathy. Excision of the annular ligament (Option E) is relevant in specific elbow instability cases but not for lateral epicondylitis.
Question 2873
Topic: 9. Shoulder and Elbow
A 28-year-old male sustains a complete avulsion of the C5-T1 nerve roots from the spinal cord following a high-energy motorcycle accident, resulting in a flail upper extremity. Clinical examination and MRI confirm preganglionic avulsion. Electromyography (EMG) at 3 months post-injury shows no signs of reinnervation. What is the most appropriate surgical option to restore some function?
Correct Answer & Explanation
. Nerve transfers (e.g., intercostal nerves, accessory nerve) to restore shoulder and elbow function.
Explanation
In a preganglionic brachial plexus avulsion, the nerve roots are torn from the spinal cord, making direct repair or grafting impossible as there is no distal stump from the spinal cord. Therefore, nerve transfers are the preferred surgical option. This involves transferring healthy, expendable nerves (e.g., intercostal nerves, spinal accessory nerve, contralateral C7) to reinnervate critical muscles, primarily for shoulder stability, elbow flexion, and potentially wrist extension. Neurolysis and direct repair/grafting are only possible for postganglionic injuries where the nerve continuity can be restored. Shoulder arthrodesis is a salvage procedure for a completely flail arm, usually performed after nerve reconstruction attempts have failed or are not indicated.
Question 2874
Topic: 9. Shoulder and Elbow
A 38-year-old overhead athlete reports progressive right arm and hand pain, numbness in the ulnar distribution, and easy fatigability of the arm with overhead activities. Physical exam reveals a positive Adson's test, and reproduction of symptoms with hyperabduction. Nerve conduction studies and EMG are normal, and cervical MRI is unremarkable. What is the most appropriate initial management for this condition?
Correct Answer & Explanation
. Physical therapy focusing on posture, shoulder girdle strengthening, and nerve gliding exercises.
Explanation
This patient presents with symptoms highly suggestive of neurogenic thoracic outlet syndrome (TOS), characterized by pain, paresthesias in an ulnar distribution, and arm fatigability with overhead activities, exacerbated by specific maneuvers (Adson's, hyperabduction). Crucially, EMG and NCS are often normal in neurogenic TOS. Given no 'hard signs' of vascular compromise or severe neurological deficit, the initial management is conservative. Physical therapy, focusing on correcting posture, strengthening shoulder girdle muscles, stretching tight scalenes/pectorals, and nerve gliding exercises, is the cornerstone of initial treatment and is successful in a significant number of patients. Botox injections are experimental and reserved for specific cases. Surgical decompression is considered if conservative treatment fails. Angiography is for vascular TOS. Opioids are for symptom management, not treatment of the underlying cause.
Question 2875
Topic: Elbow & Forearm
A 10-year-old girl with multiple hereditary exostoses presents with progressive deformity of her left forearm. Radiographs demonstrate a large distal ulnar osteochondroma. Which of the following patterns of deformity is most characteristic of this condition in the forearm?
Correct Answer & Explanation
. Ulnar shortening, radial bowing, and radial head dislocation
Explanation
Correct Answer: Ulnar shortening, radial bowing, and radial head dislocationIn Multiple Hereditary Exostoses (MHE), osteochondromas frequently affect the distal ulna because of its small cross-sectional area and relatively high growth contribution. The osteochondroma tethers the growth of the distal ulna, leading to ulnar shortening. Because the radius continues to grow, it becomes relatively overgrown, leading to radial bowing. The tethering effect at the distal radioulnar joint combined with the continued radial growth eventually forces the radial head to dislocate proximally at the radiocapitellar joint. This triad (ulnar shortening, radial bowing, radial head dislocation) is the classic forearm deformity in MHE.
Question 2876
Topic: Elbow & Forearm
A 10-year-old boy with multiple hereditary exostoses presents with a progressive forearm deformity. Radiographic evaluation is most likely to demonstrate which of the following patterns?
Correct Answer & Explanation
. Shortening of the ulna, bowing of the radius, and ulnar deviation of the carpus.
Explanation
Correct Answer: Shortening of the ulna, bowing of the radius, and ulnar deviation of the carpus.In Multiple Hereditary Exostoses (MHE), forearm deformities are common. The distal ulna contributes a larger percentage to the overall longitudinal growth of the ulna compared to the distal radius's contribution to the radius. Furthermore, the distal ulna has a smaller cross-sectional area, making it more susceptible to growth tethering by osteochondromas. This leads to disproportionate shortening of the ulna. The continued growth of the radius against the tethered ulna causes radial bowing, secondary radial head subluxation/dislocation, and an increased distal radial articular angle leading to ulnar deviation of the carpus.
Question 2877
Topic: Elbow & Forearm
A 12-year-old boy with multiple hereditary exostoses presents with progressive forearm deformity. Radiographs reveal a large osteochondroma at the distal ulna, relative shortening of the ulna, bowing of the radius, and ulnar deviation of the carpus. What is the primary biomechanical cause of the radial head dislocation often seen in this condition?
Correct Answer & Explanation
. Tethering effect of the shortened ulna causing increased compressive forces on the radius
Explanation
Correct Answer: Tethering effect of the shortened ulna causing increased compressive forces on the radiusIn multiple hereditary exostoses, osteochondromas frequently involve the distal ulna, leading to premature physeal arrest and relative shortening of the ulna. Because the radius and ulna are bound together by the interosseous membrane, the shortened ulna acts as a tether. As the radius continues to grow, this tethering creates significant compressive forces, leading to radial bowing and eventually pushing the radial head out of the radiocapitellar joint (dislocation). This is a classic mechanism of deformity in MHE forearms.
Question 2878
Topic: 9. Shoulder and Elbow
A 35-year-old male with untreated syringomyelia presents with massive swelling, instability, and crepitus of his right shoulder. He reports minimal pain despite severe radiographic destruction of the glenohumeral joint. What is the underlying pathophysiology of his joint destruction?
Correct Answer & Explanation
. Loss of protective proprioceptive and nociceptive reflexes
Explanation
The patient has a Charcot (neuropathic) joint of the shoulder, classically associated with syringomyelia. The loss of pain and proprioceptive sensation leads to repetitive microtrauma and severe joint destruction.
Question 2879
Topic: 9. Shoulder and Elbow
In the classical neurological presentation of syringomyelia, the loss of pain and temperature sensation occurs bilaterally across the shoulders and upper extremities. This specific deficit results from the syrinx compressing which of the following?
Correct Answer & Explanation
. Anterior white commissure
Explanation
The syrinx typically begins in the central canal and expands outward. The first fibers it disrupts are the spinothalamic tract fibers that are decussating (crossing) in the anterior white commissure, leading to a bilateral loss of pain and temperature sensation at the level of the lesion.
Question 2880
Topic: 9. Shoulder and Elbow
Neuropathic (Charcot) arthropathy of the upper extremity, particularly affecting the shoulder or elbow, is most commonly associated with which of the following underlying conditions?
Correct Answer & Explanation
. Syringomyelia
Explanation
While diabetes is the most common cause of Charcot joints in the foot and ankle, syringomyelia is the most common cause of neuropathic arthropathy in the upper extremities (shoulder and elbow) due to central cord disruption.
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