title: Radiological findings for hip dysplasia at skeletal maturity. Validation of digital and manual measurement techniques.
abstract: OBJECTIVE
  To report on intra-observer, inter-observer, and inter-method reliability and agreement for radiological measurements used in the diagnosis of hip dysplasia at skeletal maturity, as obtained by a manual and a digital measurement technique.
  
  
  METHODS
  Pelvic radiographs from 95 participants (56 females) in a follow-up hip study of 18- to 19-year-old patients were included. Eleven radiological measurements relevant for hip dysplasia (Sharp's, Wiberg's, and Ogata's angles; acetabular roof angle of Tönnis; articulo-trochanteric distance; acetabular depth-width ratio; femoral head extrusion index; maximum teardrop width; and the joint space width in three different locations) were validated. Three observers measured the radiographs using both a digital measurement program and manually in AgfaWeb1000. Inter-method and inter- and intra-observer agreement were analyzed using the mean differences between the readings/readers, establishing the 95% limits of agreement. We also calculated the minimum detectable change and the intra-class correlation coefficient.
  
  
  RESULTS
  Large variations among different radiological measurements were demonstrated. However, the variation was not related to the use of either the manual or digital measurement technique. For measurements with greater absolute values (Sharp's angle, femoral head extrusion index, and acetabular depth-width ratio) the inter- and intra-observer and inter-method agreements were better as compared to measurements with lower absolute values (acetabular roof angle, teardrop and joint space width).
  
  
  CONCLUSIONS
  The inter- and intra-observer variation differs notably across different radiological measurements relevant for hip dysplasia at skeletal maturity, a fact that should be taken into account in clinical practice. The agreement between the manual and digital methods is good.
authors.affiliation: Department of Surgical Sciences, University of Bergen, Bergen, Norway. Ingvild.Engeseter@helse-bergen.no
authors.forename: Ingvild Øvstebø
authors.initials: IØ
authors.lastname: Engesæter
authors.forename: Lene Bjerke
authors.initials: LB
authors.lastname: Laborie
authors.forename: Trude Gundersen
authors.initials: TG
authors.lastname: Lehmann
authors.forename: Francesco
authors.initials: F
authors.lastname: Sera
authors.forename: Jonas
authors.initials: J
authors.lastname: Fevang
authors.forename: Douglas
authors.initials: D
authors.lastname: Pedersen
authors.forename: José
authors.initials: J
authors.lastname: Morcuende
authors.forename: Stein Atle
authors.initials: SA
authors.lastname: Lie
authors.forename: Lars Birger
authors.initials: LB
authors.lastname: Engesæter
authors.forename: Karen
authors.initials: K
authors.lastname: Rosendahl
mesh_terms: D000293:Adolescent; D000465:Algorithms; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult