Spur formation is often found on the acromial undersurface in cases of rotator cuff tear. The spur formation is thought to contribute to the occurrence and progress of the rotator cuff tear.
Our series consisted of 40 joints of 36 men and 15 joints of 15 women. The average age (range,30 to 82) at the time of operation was 58.8. There were 26 joints (47.2%) with a spur on the acromial undersurface (spur group), and 29 joints (52.8%) without a spur (non-spur group). The average age of the spur group and that of the non-spur group at the time of operation was 62.7 and 55.2, respectively. The difference in the average age of the two groups was significant. The location of the spur formation extended from the front to the outside of the acromion on the X-ray in most cases. Narrowness of the acromio-humeral interval and spur formation on the glenoid and humerus occurred much more frequently in the spur group than in the non-spur group.
A Combination o f anterior acromioplasty and McLaughlin's method was performed in most cases (47 joints). At operation, wide rupture was found in 12 (46.2%) of 24 joints in the spur group, but only in 8 (27.6%) of 29 joints in the non-spur group.
Postoperative results were examined in the 26 joints of the spur group and 24 in the non spur group. No difference was found between the two groups in postoperative results.
Radiographically the spur resected at operation was formed in a segmental f a shion and the bone trabecular structure was irregular. Histologically the normal structure of four layers seen at the anterior undersurface of the acromion was disturbed.
