The subacromial bursa and the impingement syndrome. A clinical and histological study of 30 cases.

Biopsies from the subacromial bursa were obtained from 30 patients with an impingement syndrome and from an autopsy series of 13 "normal" shoulders. Bursal fibrosis seemed to be a characteristic of the patient group; inflammatory cells, found in 7/30 specimens from the patients, were not found in the autopsy series. The microscopic findings could not be predicted from peroperative observations. There was an association between a poor outcome of surgery and absence of bursal fibrosis.