title: Measurement of structural progression in osteoarthritis of the hip: the Barcelona consensus group.
abstract: OBJECTIVE
  To outline the best available method of measurement for detecting progression of osteoarthritis (OA) of the hip especially in therapeutic trials.
  
  
  METHODS
  A Medline search of articles related to progression of hip OA was performed. A group of experts met over a 1.5-day session to review available literature and new research. Specific questions were addressed in order to reach a consensus on measuring progression of OA of the hip.
  
  
  RESULTS
  Of the available surrogate measures, a single yearly standing or reclined antero-posterior plain radiograph of the pelvis with feet internally rotated 15-20 degrees, can be evaluated with the use of an atlas for joint space width (JSW, interbone distance). There should be a minimum JSW upon baseline screening that may be 1 or 2 mm. Digitization of films offers a slight reduction in variability of measurements. Progression of OA can be calculated by measurement of the JSW on paired and blinded films. A reduction of > or = 0.5 mm is greater than the 'minimum perceptible difference' as well as the variation of most imaging techniques, and represents a clinically relevant and significant reduction in the JSW. Narrowing of the superomedial or superolateral JSW may tend to progress more rapidly than other changes. In clinical trials, patients who discontinue the study treatment need to be followed after discontinuation, and an imputation strategy which provides unbiased estimates of both the treatment effect and its variance is an appropriate technique for intent-to-treat analysis.
  
  
  CONCLUSIONS
  For the development of new agents intended to prevent, retard, stabilize or reverse the progress of OA of the hip, the radiographic methodology presently available is adequate to detect changes in hip JSW of OA.
authors.affiliation: Division of Rheumatology, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA, USA. journals@royaltman.com
authors.forename: R D
authors.initials: RD
authors.lastname: Altman
authors.forename: D A
authors.initials: DA
authors.lastname: Bloch
authors.forename: M
authors.initials: M
authors.lastname: Dougados
authors.forename: M
authors.initials: M
authors.lastname: Hochberg
authors.forename: S
authors.initials: S
authors.lastname: Lohmander
authors.forename: K
authors.initials: K
authors.lastname: Pavelka
authors.forename: T
authors.initials: T
authors.lastname: Spector
authors.forename: E
authors.initials: E
authors.lastname: Vignon
mesh_terms: D001182:Arthroscopy; D015415:Biomarkers / Q000032:analysis; D002986:Clinical Trials as Topic / Q000379:methods; D018450:Disease Progression; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging* / Q000473:pathology; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers