A 44-year-old man comes to the office for follow-up after being evaluated in the emergency department for a shoulder injury. Two weeks ago, the patient fell on an outstretched hand at work; x-ray in the hospital showed a posterior glenohumeral dislocation without fracture. The dislocation was reduced successfully under procedural sedation, and the arm was placed in a sling. The patient was advised to follow up with the outpatient provider in 2 weeks. Since the injury, he has been unable to abduct the arm without severe pain and difficulty. He has no medical history and takes no medications regularly. On examination, the patient has no shoulder numbness but has limited abduction due to pain. Distal pulses and sensation are intact. There is no shoulder asymmetry. Which of the following is the most likely cause of this patient's current symptoms?

Question

A 44-year-old man comes to the office for follow-up after being evaluated in the emergency department for a shoulder injury.  Two weeks ago, the patient fell on an outstretched hand at work; x-ray in the hospital showed a posterior glenohumeral dislocation without fracture.  The dislocation was reduced successfully under procedural sedation, and the arm was placed in a sling.  The patient was advised to follow up with the outpatient provider in 2 weeks.  Since the injury, he has been unable to abduct the arm without severe pain and difficulty.  He has no medical history and takes no medications regularly.  On examination, the patient has no shoulder numbness but has limited abduction due to pain.  Distal pulses and sensation are intact.  There is no shoulder asymmetry.  Which of the following is the most likely cause of this patient's current symptoms?

Quizplus · Accepted Answer

11ec25c8_d976_2c85_bc81_55a2561d0cf5_MD0003_00 This patient experienced a posterior glenohumeral dislocation following a fall on an outstretched hand. The dislocation was successfully reduced in the emergency department, but he now has pain and difficulty abducting the arm. This presentation suggests a rotator cuff injury (RCI), a common complication of shoulder dislocation in patients age >40 (>50% patients). Around 15% of patients may have a complete tear. fall on an outstretched hand The rotator cuff is a group of 4 muscles (ie, supraspinatus, infraspinatus, teres minor, subscapularis) and tendons that surround the shoulder joint, stabilizing the humeral head in the glenoid fossa. RCI usually presents with pain in the lateral shoulder that is worse with abduction over the head, at night, and when sleeping on the affected shoulder. Rupture of the supraspinatus tendon is a common variant and is characterized by decreased abduction with intact sensation. rotator cuff RCI is not normally seen on x-ray, and examination findings may be masked by generalized pain and guarding at the time of initial injury (eg, shoulder dislocation). However, the extent of injury often becomes apparent as the acute symptoms improve in subsequent days to weeks. The diagnosis can be confirmed with MRI. (Choice A) Adhesive capsulitis, also known as frozen shoulder, develops progressively over months and causes restriction in all planes of shoulder movement, not only abduction. This is not an acute condition that develops immediately after an injury. (Choice B) Avascular necrosis of the humeral head can cause pain with abduction. However, it is much more common when dislocation is associated with a proximal humerus fracture, which this patient does not have; rarely, it can be associated with severe dislocations. The pain develops gradually, unlike the pain in this patient, who had difficulty with abduction immediately after the injury. (Choice C) The axillary nerve runs anterior to the glenohumeral joint and can be injured in shoulder dislocation. It innervates the teres minor and deltoid muscles, and injury can mimic RCI with pain and weakness of abduction; however, the associated sensory loss over the lateral shoulder area differentiates it from RCI. shoulder dislocation (Choice D) Recurrent dislocation is unlikely, given that the patient has no asymmetry on examination and can move the shoulder freely, except during abduction. Educational objective: Shoulder dislocation is commonly associated with rotator cuff injury (RCI), which presents as shoulder pain and difficulty with abduction. RCI can cause weakness but not sensory loss. References: Rotator cuff tear and glenohumeral instability: a systematic review. (http://www.ncbi.nlm.nih.gov/pubmed/24043432)

A 44-Year-Old Man Comes to the Office for Follow-Up After