title: Quantitative measures for evaluating the radiographic outcome of Legg-Calvé-Perthes disease.
abstract: BACKGROUND
  Large sample sizes are needed if discrete outcome measures are used to perform outcome studies, whereas more practicable sample sizes are sufficient if continuous outcome measures are used. Recognizing the need to devise reliable continuous outcome measures for assessing the outcomes of treatment of Legg-Calvé-Perthes disease, we evaluated a method of quantifying the shape and size of the femoral head and the femoral-acetabular relationship from computer images of anteroposterior and lateral radiographs with the help of image-analysis software.
  
  
  METHODS
  Radiographs of 121 skeletally mature individuals with healed Legg-Calvé-Perthes disease were analyzed, and the sphericity deviation score, femoral head enlargement, femoral neck growth inhibition, and composite femoral congruency arc were calculated.
  
  
  RESULTS
  Each of these measurements was reproducible, with distinctly different values for hips in each of the Stulberg classes. Measures of sphericity and congruence (the sphericity deviation score and the composite femoral congruency arc) could very clearly discriminate between spherical and aspherical hips, and there was a strong correlation between these two measurements.
  
  
  CONCLUSIONS
  The study shows that it is possible to have reliable quantitative measures of the outcome of Legg-Calvé-Perthes disease at skeletal maturity.
authors: Paediatric Orthopaedic Service, Department of Orthopaedics, Kasturba Medical College, Manipal 576 104, Karnataka State, India.
authors: Hitesh
authors: H
authors: Shah
authors: N D
authors: ND
authors: Siddesh
authors: Harish
authors: H
authors: Pai
authors: Stéphane
authors: S
authors: Tercier
authors: Benjamin
authors: B
authors: Joseph
mesh_terms: D000704:Analysis of Variance; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006801:Humans; D007873:Legg-Calve-Perthes Disease / Q000000981:diagnostic imaging* / Q000628:therapy*; D008297:Male; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D016896:Treatment Outcome