Chronic shoulder pain: part I. Evaluation and diagnosis.

Shoulder pain is defined as chronic when it has been present for longer than six months. Common conditions that can result in chronic shoulder pain include rotator cuff disorders, adhesive capsulitis, shoulder instability, and shoulder arthritis. Rotator cuff disorders include tendinopathy, partial tears, and complete tears. A clinical decision rule that is helpful in the diagnosis of rotator cuff tears includes pain with overhead activity, weakness on empty can and external rotation tests, and a positive impingement sign. Adhesive capsulitis can be associated with diabetes and thyroid disorders. Clinical presentation includes diffuse shoulder pain with restricted passive range of motion on examination. Acromioclavicular osteoarthritis presents with superior shoulder pain, acromioclavicular joint tenderness, and a painful cross-body adduction test. In patients who are older than 50 years, glenohumeral osteoarthritis usually presents as gradual pain and loss of motion. In patients younger than 40 years, glenohumeral instability generally presents with a history of dislocation or subluxation events. Positive apprehension and relocation are consistent with the diagnosis. Imaging studies, indicated when diagnosis remains unclear or management would be altered, include plain radiographs, magnetic resonance imaging, ultrasonography, and computed tomography scans. Plain radiographs may help diagnose massive rotator cuff tears, shoulder instability, and shoulder arthritis. Magnetic resonance imaging and ultrasonography are preferred for rotator cuff disorders. For shoulder instability, magnetic resonance imaging arthrogram is preferred over magnetic resonance imaging.