title: Changes in load-bearing area after Ganz periacetabular osteotomy evaluated by multislice CT scanning and stereology.
abstract: BACKGROUND
  We used a stereologic method based on 3D CT scanning to estimate the projected load-bearing surface in the hip joint.
  
  
  METHODS
  6 normal hip joints and 6 dysplastic hips were examined. The latter were CT-scanned before and after periacetabular osteotomy.
  
  
  RESULTS
  We found that the average area of the projected load-bearing surface of the femoral head preoperatively was 7.4 (6.5-8.4) cm2 and postoperatively 11 (9.8-14) cm2, which was similar to the load-bearing surface in the normal control group. We performed double measurements and the coefficient of error of the mean was estimated at 1.6%. Due to overprojection, an overestimation of about 3.8% on the projected load-bearing surface occurred. Consequently, the stereologic method proved to be precise and unbiased.
  
  
  CONCLUSIONS
  Our findings indicate that this method is of value for monitoring the load-bearing area in the hip joint of patients undergoing periacetabular osteotomy.
authors.affiliation: Stereological Research and Electron Microscopy Laboratory, University of Aarhus, Denmark. Inger.Mechlenburg.afm@km.dk
authors.forename: Inger
authors.initials: I
authors.lastname: Mechlenburg
authors.forename: Jens R
authors.initials: JR
authors.lastname: Nyengaard
authors.forename: Lone
authors.initials: L
authors.lastname: Rømer
authors.forename: Kjeld
authors.initials: K
authors.lastname: Søballe
mesh_terms: D000077:Acetabulum; D000328:Adult; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D007592:Joint Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D010027:Osteotomy / Q000379:methods*; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D016474:Weight-Bearing