Internal impingement in the shoulder of the overhand athlete: pathophysiology, diagnosis, and treatment.

The etiology of rotator cuff disease is multifactorial in nature. The process by which the articular surface of the rotator cuff can become diseased secondary to direct abutment against the glenoid rim and labrum has been termed internal impingement. Damage to the undersurface of the rotator cuff can occur from contact at the extremes of shoulder motion and can increase secondary to adaptive changes in bone and soft tissue. Diagnosis is achieved in most instances by a thorough physical examination. Adjunctive tests, particularly magnetic resonance imaging, can increase the accuracy of the diagnosis. If this disease is recognized early, nonoperative intervention may be successful. When nonoperative treatment fails, the use of arthroscopy for the treatment of torn rotator cuff and labral tissue and capsular laxity may be indicated to resolve symptoms and restore the premorbid level of function.