title: A magnetic resonance imaging study of 100 cases of arthroscopic acromioplasty.
abstract: BACKGROUND
  A hooked-type acromion has been suspected to correlate with higher rotator cuff tear or impingement syndrome. However, correlation of acromial shape after acromioplasty with the rotator cuff retears and clinical results has not been studied before.
  
  
  OBJECTIVE
  To assess the shape of the acromion after arthroscopic acromioplasty and to see if there is any relation with the rotator cuff retears and clinical results.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  One hundred consecutive patients who underwent acromioplasty using a posterior cutting block technique accompanied by rotator cuff repair were included in this study. The decision was made to perform acromioplasty intraoperatively after confirmation of external impingement. Postoperative acromial shape was evaluated according to whether the acromion was flat, curved, or hooked on coronal and sagittal planes on magnetic resonance imaging (MRI) at a mean 13.4 months after surgery. Retear rates and clinical scores were compared between the hooked acromion and the others on postoperative MRI.
  
  
  RESULTS
  Preoperatively, only 29 patients had a hooked acromion on either coronal or sagittal plane MRI. After acromioplasty of those 100 patients, 23 still showed a hooked acromion. Twenty-six of 29 preoperatively hooked acromions were changed to nonhooked acromions, and 20 of 23 postoperatively hooked acromions had been nonhooked acromions preoperatively. No difference was found in the retear rate with respect to the postoperative acromial shape. Clinically, the American Shoulder and Elbow Surgeons (ASES) score was not different between the hooked acromion and the other group (82 vs 85, P = .099). However, the Constant score of the hooked acromion group was lower than that of the other group (74 vs 85, P = .036). Ninety-four of 100 patients were contacted again for the evaluation of the ASES score at a mean 36.5 months (range, 29-45 months) and showed no difference between the hooked acromion and the other group (87 vs 87, P = .903).
  
  
  CONCLUSIONS
  Even with a standard posterior cutting block technique during acromioplasty, 23% of patients still showed a hooked acromion after arthroscopic acromioplasty. Using the signs of coracoacromial ligament impingement as an indication for acromioplasty might lead to hooked acromions postoperatively, which were nonhooked acromions preoperatively. However, the retear rate showed no difference according to the postoperative acromial shape.
authors.affiliation: Department of Orthopaedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Kyoung Hwan
authors.initials: KH
authors.lastname: Koh
authors.forename: Mukesh S
authors.initials: MS
authors.lastname: Laddha
authors.forename: Tae Kang
authors.initials: TK
authors.lastname: Lim
authors.forename: Jong Hyuk
authors.initials: JH
authors.lastname: Lee
authors.forename: Jae Chul
authors.initials: JC
authors.lastname: Yoo
mesh_terms: D000173:Acromioclavicular Joint / Q000033:anatomy & histology / Q000601:surgery; D000174:Acromion / Q000033:anatomy & histology* / Q000601:surgery*; D000328:Adult; D000368:Aged; D001178:Arthroplasty; D001182:Arthroscopy; D016009:Chi-Square Distribution; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D017006:Rotator Cuff / Q000601:surgery; D000070636:Rotator Cuff Injuries; D018709:Statistics, Nonparametric