To identify whether acromial shape, osteophyte, and acromio-humeral interval have effects on impingement syndrome or rotator cuff tear, we reviewed 40 cases of normal group (F:M=22:18), and 30 cases of impingement syndrome(F:M=16:4). Forty cases of normal group aged from 40 to 69 who had no pain, no abrasion sign, no limitation of motion, and normal function of shoulder joint were selected. Thirty cases of impingement syndrome were managed by acromioplasty or direct repair from October, 1993 to May, 1994. Twenty-five cases of 30 were identified rotator cuff tear(RCT), and the others were turned out subacromial abrasion. We reviewed the acromial thickness, the acromial shape, the anterior protuberance, the presence of osteophyte, and the acromio-humeral interval to compare the difference between two groups.

Forty-seven point five per cent of normal group had a flat, type I acromion, 47.5% had a curved, type II acromion and 5% were identified by a hooked, type III acromion. However, in subjects with impingement syndrome and RCT, 37% had type I, 20% had type II. and 43% displayed type III. Type III was considerably noticed in the massive tear. In regarding to acromial thickness, normal group had type A(less than 8 mm)-37.5%, type B(8-12 mm)-62.5%, and the impingement syndrome or RCT group had type A-53%, type B-47%. We couldn’t find any significant difference with each group in the acromial thickness. Anterior protuberance was type I(less than 4mm)-50%. type II(4-8mm) -35%, type III(more than 8 mm)-15% in normal, and type I-17%, type II-33%. type III-50% in the impingement syndrome or RCT. It was suggested that the anterior protuberance was related with the evidence of RCT. A-H interval was 10.25mm 1.46mm in normal, and 9.44mm 1.70mm in the impingement syndrome or RCT. There was no significance in A-H interval except rotator cuff arthropathy. Thirty three percent of normal group had osteophytes and 40% of impingement syndrome or RCT had osteophytes on the undersurface of acromion.