Subacromial impingement syndrome.

Subacromial impingement syndrome (SAIS) represents a spectrum of pathology ranging from subacromial bursitis to rotator cuff tendinopathy and full-thickness rotator cuff tears. The relationship between subacromial impingement and rotator cuff disease in the etiology of rotator cuff injury is a matter of debate. However, the etiology is multi-factorial, and it has been attributed to both extrinsic and intrinsic mechanisms. Management includes physical therapy, injections, and, for some patients, surgery. No high-quality randomized controlled trials are available so far to provide possible evidence for differences in outcome of different treatment strategies. There remains a need for high-quality clinical research on the diagnosis and treatment of SAIS.