抄録
Large histologic sections from twelve surgical specimens were studied in order to clarify the pathogenesis of the bursal side rotator cuff tears (BSRCT). The specimen consisted of the bony insertion, the partially torn area and the musculotendinous junction of the supraspinatus tendon. There were eight men and four women with an average age of 48.7 years. Trauma was noted in three shoulders. All patients exhibited clinical evidences of subacromial impingement which were also confirmed at surgery. Histologic sections were stained with hematoxylin & eosin and Azan. All the tears developed from within 1.0 cm of the insertion. The depth of the tears varied from a superficial flap to almost a full thickness tear. Microscopically, the sections demonstrated the following abnormalities in addition to degeneration. At the site of insertion and in the distal stumps, local disruptions of the normal four layers of enthesis and areas of hypervascularity were observed in all. The proximal stumps were rounded, retracted and avascular with abundant chondrocytes. No active repair was noted in the proximal stumps. The pathogenesis of BSRCT appears to be related to a combination of aging and precarious vascularity of the tendon, repeated use of the arm above-horizontal level or injury and most importantly to subacromial tendon impingement.
