Rotator cuff tears associated with os acromiale.

We studied the cases of eight patients, one with bilateral involvement, who had a rotator cuff tear and an associated lesion delineated roentgenographically - a separate fragment of the acromion that we believe to be an ununited ossification center of the acromion (os acromiale). In reviewing the literature, we found no mention of an association between a rotator cuff tear and os acromiale. It is highly unlikely that such an association is coincidental because it appears that in our patients abnormal motion existed through the site of fibrous union of the acromion and may have contributed to the impingement of the acromion on the rotator cuff. Repair of the rotator cuff with removal of the loose fragment of acromion was done in the six patients who had operative treatment.