title: Reliability of two-dimensional computed tomography for measuring hip anatomy.
abstract: OBJECTIVE
  To evaluate the reliability (inter- and intra-observer variability) of 4 hip anatomies using 2-dimensional pelvic computed tomography (CT).
  
  
  METHODS
  Two-dimensional pelvic CT of 10 men and 10 women aged 33 to 89 (mean, 69) years presenting with non-orthopaedic conditions within one month were evaluated by 3 observers. The centre-edge angle of Wiberg, the Sharp angle, the acetabular depth ratio of Murray, and the acetabular anteversion angle of every hip were measured by each observer. After 6 weeks, these measurements were repeated. Reliability was evaluated using intraclass correlation coefficient (ICC), which represents the variation between patients as a percentage of the variation from all 3 sources (patients, inter-observers, and intra-observers). The ICC was classified as poor (<0.20), fair (0.21-0.40), moderate (0.41-0.60), substantial (0.61-0.80), and excellent (0.81-1.00).
  
  
  RESULTS
  Reliability was substantial for the Sharp angle (ICC=0.74), the acetabular anteversion angle (ICC=0.69), and the acetabular depth ratio of Murray (ICC=0.62), and was fair for the centre-edge angle of Wiberg (ICC=0.40).
  
  
  CONCLUSIONS
  The Sharp angle, the acetabular anteversion angle, and the acetabular depth ratio of Murray could be reliably measured using 2-dimensional CT. These measurements are appropriate for population-based studies of hip anatomy.
authors: Department of Orthopaedic Surgery, Tauranga Hospital, Tauranga, New Zealand. drmattboyle@hotmail.com
authors: Matthew J
authors: MJ
authors: Boyle
authors: Omid
authors: O
authors: Yassaie
authors: Philip P
authors: PP
authors: Grieve
authors: Christopher M A
authors: CM
authors: Frampton
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006621:Hip Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: anatomy, cross-sectional; hip joint; reproducibility of results; tomography, X-ray computed