Impingement syndrome and rotator cuff disease as repetitive motion disorders.

The relationship between repetitive motion and subacromial impingement and rotator cuff disease is controversial and poorly understood. The potential etiology is multifactorial and involves patient related factors (age, supraspinatus outlet anatomy, and preexisting rotator cuff pathology) and worker related factors (arm position, lifting requirements, numbers of repetitions). Radiographic and magnetic resonance imaging abnormalities may represent preexisting disease that could have predisposed the patient to the development of impingement syndrome, but should be interpreted cautiously within the context of the remainder of the clinical picture. Treatment often involves temporary or permanent modifications of the work environment.