title: Comparison of a computer based method and the classical manual method for radiographic joint space width assessment in hip osteoarthritis.
abstract: OBJECTIVE
  To compare the intraobserver reliability and the sensitivity to change of 2 techniques evaluating the cartilage breakdown in hip osteoarthritis (OA).
  
  
  METHODS
  
  
  
  METHODS
  3 year longitudinal study.
  
  
  METHODS
  patients with painful hip OA.
  
  
  RESULTS
  coxofemoral joint space width (JSW) at baseline and at 3 year followup was measured on anteroposterior weight-bearing radiographs by 2 methods: a manual method to obtain JSW at the narrowest point (minimal JSW) using a 0.1 mm graduated magnifying glass and a computer based method to obtain minimal and average JSW.
  
  
  METHODS
  Two assessments, at one month interval, of each pair of films; evaluation of the intraobserver reliability using the intraclass coefficient of correlation, and the Bland and Altman approach, obtaining the smallest detectable difference (SDD). For each technique, percentage of progressors was evaluated, i.e., the percentage of patients with change greater than the SDD. Evaluation of sensitivity to change was performed using the standardized response mean (SRM), with 95% CI calculated using the jackknife method.
  
  
  RESULTS
  Twenty-five pairs of films were evaluated. There were no statistically significant differences between the 3 analyses in the calculated intraclass coefficients of correlation, percentage of progressors, or SRM.
  
  
  CONCLUSIONS
  These results suggest that both techniques are reliable and sensitive enough to detect changes in a relevant percentage of patients with hip OA after a 3 year followup.
authors.affiliation: René Descartes University, Institute of Rheumatology, Paris, France.
authors.forename: Jean Francis
authors.initials: JF
authors.lastname: Maillefert
authors.forename: John T
authors.initials: JT
authors.lastname: Sharp
authors.forename: Ludwig Serge
authors.initials: LS
authors.lastname: Aho
authors.forename: Maxime
authors.initials: M
authors.lastname: Dougados
mesh_terms: D000368:Aged; D001175:Arthrography / Q000379:methods*; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging*; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method