Calcific tendinitis of the rotator cuff showing a contracted state of abduction: a report of four cases.

This report describes four patients with calcific tendinitis of the rotator cuff that resulted in an abduction contracture. Similarities included an acute onset, lack of tenderness in the shoulder, x-ray demonstration of large calcific deposits in the supraspinatus tendon, and the radiographic appearance of the greater tuberosity under the acromion. The abduction contracture is presumably caused by mechanical blocking by the calcified deposits and the coracoacromial arch and by reflex muscle spasm caused by pain.