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Shoulder pain is a common musculoskeletal complaint, especially in patients older than 40 years. Occupational, recreational, and normal daily activities stress the shoulder joint and may result in pain from acute injury or, more commonly, chronic overuse conditions. Complicating the evaluation of shoulder pain is that the origin of pain may be from pathology intrinsic to the shoulder joint or from extrinsic disorders causing referred pain.
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The pain of musculoskeletal shoulder pathology often is described by patients as an aching sensation, particularly in the setting of a more chronic process. Nighttime pain is a common feature of intrinsic shoulder pathology. Specific motions may exacerbate it, and this history is helpful in making a specific diagnosis. Decreased range of motion, crepitus, weakness, or muscular atrophy may be associated with certain conditions. Any systemic symptoms (eg, shortness of breath, fever, or radiation of pain from the chest or abdomen) should raise suspicion for extrinsic and potentially life-threatening problems.
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The primary diagnostic maneuver is a thorough history and physical examination. Examination of the shoulder joint should include range of motion and muscle strength testing, palpation for local tenderness or other abnormality, and identification of any neurovascular deficit. Specific tests for impingement and individual tests of rotator cuff muscle function are often helpful in intrinsic disease. Plain radiographic studies of the shoulder joint are rarely diagnostic but may be helpful to exclude bony abnormalities in selected patients or to evaluate for abnormal calcifications. In patients in whom extrinsic causes of shoulder pain are suspected, further diagnostic testing may be indicated, such as laboratory studies, additional radiographs, and an electrocardiogram.
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The differential diagnosis includes a variety of intrinsic musculoskeletal disorders, and individual patients may exhibit considerable overlap in their symptoms manifesting a combination of specific conditions. Impingement syndrome is a term that has been adopted to encompass many painful shoulder syndromes that result most frequently from repetitive overhead use of the arm. The pathologic entities included in this syndrome are subacromial tendonitis and bursitis, supraspinatus tendonitis, rotator cuff tendonitis, and the painful arc syndrome. Impingement syndrome is a painful overuse condition characterized by positive findings with impingement testing and relief of pain with anesthetic injection of the subacromial space. Subacromial bursitis is generally seen in patients younger than 25 years and will present with positive impingement tests with different degrees of tenderness at the lateral proximal humerus or in the subacromial space. Rotator cuff tendonitis is distinguished by an incidence primarily in individuals 25 to 40 years of age and findings of tenderness of the rotator cuff with mild to moderate muscular weakness. In more chronic disease, crepitus, decreased range of motion, and osteophyte formation visible on plain radiograph also may be apparent. Rotator cuff tears occur primarily in patients older than 40 years and are associated with muscular weakness (especially with abduction and external rotation) and cuff tenderness. Ninety percent will be chronic tears with a history of minimal or no trauma; ...