Pathogenesis of partial tear of the rotator cuff: a clinical and pathologic study.

This prospective study investigated the clinical and pathologic results in 66 patients with partial tears of the rotator cuff from January 1996 to December 1998. The pathologic change in the rotator cuff was graded from the magnetic resonance images by using the criteria described by Zlatkin and Iannotti. A modified grading system from Ozaki and Panni was used for pathologic grading of the anterior acromion. The functional score of Constant and Murley was used for clinical assessment. The pathologic change in the rotator cuff revealed by the magnetic resonance imaging study was more severe in patients with articular side tears compared with patients who had bursal side tears. On the contrary, the pathologic changes in the acromion were significantly milder in patients with articular side tears compared with bursal side tears. These observations indicate that articular side tears of the rotator cuff are mainly associated with intrinsic pathologic changes of the rotator cuff, whereas bursal side tears are associated with subacromial impingement on an underlying milder pathologic change of the rotator cuff.