title: The correlation between bursoscopic and histologic findings of the acromion undersurface in patients with subacromial impingement syndrome.
abstract: OBJECTIVE
  Ideally, decompression of the coracoacromial arch in patients with shoulder impingement syndrome should be done only at the site of impingement. However, it is very difficult to determine the exact site of impingement before acromioplasty. The objectives of this study were to investigate the relationship between findings and the histopathologic changes of the undersurface of the acromion in subacromial impingement syndrome and to evaluate the usefulness of bursoscopy in identifying the site of the impingement.
  
  
  METHODS
  Case series.
  
  
  METHODS
  We investigated the correlation between subacromial bursoscopic findings and histopathologic changes of the coracoacromial arch in 50 patients with subacromial impingement syndrome. The acromion and the coracoacromial ligaments removed during acromioplasty were fixed in 10% formalin, decalcified, embedded in paraffin, and cut into sections along the direction of the coracoacromial ligament. After staining with toluidine blue, the specimens were evaluated for pathology using an optical microscope.
  
  
  RESULTS
  The pathologic changes were classified into 3 types according to the direction of proliferative fibrocartilaginous changes at the enthesis of the acromial insertion of the coracoacromial ligament. The bursoscopic findings were classified into 4 types. Subacromial abnormalities in the bursoscopy findings correlated with histopathologic changes at the undersurface of the acromion. On the other hand, cases with normal findings on the undersurface of the acromion on bursoscopy had hypertrophic changes of fibrocartilage at the insertion of the coracoacromial ligament to the acromion. These results suggest that, with normal findings on the undersurface of the acromion in patients with subacromial impingement syndrome, there is impingement at the coracoacromial ligament.
  
  
  CONCLUSIONS
  Bursoscopy is a useful procedure to determine the impingement site in patients with subacromial impingement.
authors.affiliation: Department of Orthopaedic Surgery, Hokkaido University School of Medicine, Sapporo, Japan. suenaga@med.hokudai.ac.jp
authors.forename: Naoki
authors.initials: N
authors.lastname: Suenaga
authors.forename: Akio
authors.initials: A
authors.lastname: Minami
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Fukuda
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kaneda
mesh_terms: D000174:Acromion / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy / Q000379:methods*; D002061:Bursa, Synovial / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017006:Rotator Cuff / Q000473:pathology; D000070636:Rotator Cuff Injuries; D019534:Shoulder Impingement Syndrome / Q000473:pathology* / Q000601:surgery