We carried out a pathological examination of the inferior surface of the acromion in cases with rotator cuff tears to clarify the pathogenesis of such tears. Fifteen male patients with an average age of 53.3 years were operated on and all but one had a history of trauma. The lateral portion of the acromion was resected to prevent impingement syndrome and was examined microscopically to determine the degree of degeneration of the inferior surface.
Degeneration of the outer part of the resected acromion was more severe than that of the inner part. The degree of degenertion was siginificantly related with an increase in age but had no relation with the period after trauma or with the size of cuff ruphad no relation with the period after trauma or with the size of cuff rupture.
These results suggested that degeneration of the inferior surface of the acromion among middle aged men may arise with aging, or the cuff dysfunction may pre-exsist before any symptoms become apparent.