title: Responsiveness of the SF-36 and WOMAC following periacetabular osteotomy for acetabular dysplasia.
abstract: BACKGROUND
  Periacetabular osteotomy is a relatively common reconstructive procedure for the adolescent or young adult with acetabular dysplasia. Although several measures have been used to characterize the outcome, the responsiveness of these measures in this population has not been determined. The purpose of this study was to estimate the responsiveness of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Short Form-36 (SF-36) in patients with acetabular dysplasia treated with periacetabular osteotomy.
  
  
  METHODS
  Eighty-three patients with acetabular dysplasia treated with periacetabular osteotomy between 2000 and 2005 completed the WOMAC and SF-36 both preoperatively and postoperatively. The scores on each domain of these outcome measures were calculated and analyzed to determine the parameters of responsiveness, including the minimal detectable change at the 90% confidence level.
  
  
  RESULTS
  The mean duration of follow-up was 1.9 years. Comparison of the effect size, standardized response mean, and minimal detectable change for the SF-36 and WOMAC demonstrated that the WOMAC was more sensitive to change than the SF-36 was, particularly in the physical function domain (minimal detectable change, 9.1) and the pain domain (minimal detectable change, 5.5). Only one of the eight domains of the SF-36, bodily pain, demonstrated a change in outcome that exceeded the minimal detectable change, which was 2.38.
  
  
  CONCLUSIONS
  Both the WOMAC and the SF-36 demonstrated adequate responsiveness to change over time in patients with acetabular dysplasia treated with periacetabular osteotomy, although the WOMAC was more sensitive to change. These results indicate that the WOMAC is sufficiently responsive to be used as a joint-specific measure for assessing changes following periacetabular osteotomy for the treatment of acetabular dysplasia.
authors.affiliation: The Adolescent and Young Adult Hip Unit, Department of Orthopaedic Surgery, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Darin
authors.initials: D
authors.lastname: Davidson
authors.forename: Yi-Meng
authors.initials: YM
authors.lastname: Yen
authors.forename: Alan M
authors.initials: AM
authors.lastname: Jette
authors.forename: Sippy
authors.initials: S
authors.lastname: Olarsch
authors.forename: Young-Jo
authors.initials: YJ
authors.lastname: Kim
mesh_terms: D000077:Acetabulum / Q000002:abnormalities / Q000473:pathology / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010027:Osteotomy; D012720:Severity of Illness Index; D016896:Treatment Outcome