Synovial chondromatosis of the acromioclavicular joint

Summary Synovial chondromatosis involving the acromioclavicular joint is very rare. We report a case of synovial chondromatosis of the acromioclavicular joint associated with synovial cyst formation. Arthrography of the acromioclavicular joint revealed that the loose bodies lay within a synovial cyst which was in communication with the acromioclavicular joint. Synovectomy including removal of the synovial cyst and the loose bodies relieved symptoms completely. The patient was still pain- and recurrence-free at 4 years' follow-up.