title: Is the supraspinatus muscle atrophy truly irreversible after surgical repair of rotator cuff tears?
abstract: BACKGROUND
  Atrophy of rotator cuff muscles has been considered an irreversible phenomenon. The purpose of this study is to evaluate whether atrophy is truly irreversible after rotator cuff repair.
  
  
  METHODS
  We measured supraspinatus muscle atrophy of 191 patients with full-thickness rotator cuff tears on preoperative magnetic resonance imaging and postoperative multidetector computed tomography images, taken at least 1 year after operation. The occupation ratio was calculated using Photoshop CS3 software. We compared the change between pre- and postoperative occupation ratios after modifying the preoperative occupation ratio. In addition, possible relationship between various clinical factors and the change of atrophy, and between the change of atrophy and cuff integrity after surgical repair were evaluated.
  
  
  RESULTS
  The mean occupation ratio was significantly increased postoperatively from 0.44 ± 0.17 to 0.52 ± 0.17 (p < 0.001). Among 191 patients, 81 (42.4%) showed improvement of atrophy (more than a 10% increase in occupation ratio) and 33 (17.3%) worsening (more than a 10% decrease). Various clinical factors such as age tear size, or initial degree of atrophy did not affect the change of atrophy. However, the change of atrophy was related to repair integrity: cuff healing failure rate of 48.5% (16 of 33) in worsened atrophy; and 22.2% (18 of 81) in improved atrophy (p = 0.007).
  
  
  CONCLUSIONS
  The supraspinatus muscle atrophy as measured by occupation ratio could be improved postoperatively in case of successful cuff repair.
authors: Department of Orthopaedic Surgery, Konkuk University Hospital, Konkuk University School of Medicine, Seoul, Korea.
authors: Seok Won
authors: SW
authors: Chung
authors: Sae Hoon
authors: SH
authors: Kim
authors: Suk-Kee
authors: SK
authors: Tae
authors: Jong Pil
authors: JP
authors: Yoon
authors: Jung-Ah
authors: JA
authors: Choi
authors: Joo Han
authors: JH
authors: Oh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009133:Muscular Atrophy / Q000175:diagnosis*; D020127:Recovery of Function; D012189:Retrospective Studies; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D013708:Tendon Injuries / Q000175:diagnosis / Q000534:rehabilitation / Q000601:surgery*
keywords: Atrophy; Occupation ratio; Postoperative change; Rotator cuff