title: Reliability of hip migration index in children with cerebral palsy: the classic and modified methods.
abstract: OBJECTIVE
  To determine reliability and clinical use of two methods of migration index (MI) in CP patients with or without hip dysplasia.
  
  
  METHODS
  The materials included radiographs of 200 hips of children with cerebral palsy. Conventional anteroposterior radiographs of the pelvis were taken with the child in the supine position with standardized methods. Two rehabilitation doctors measured the migration index using two methods. In the classic method, the lateral margin of the acetabular roof was used as a landmark and in the modified method the lateral margin of the sourcil was used as a landmark. Each rater measured the migration index at three separate times with a time interval of at least one week. Intraclass correlation (ICC) was used to test the inter- and intra-rater reliability.
  
  
  RESULTS
  MI shows excellent intra-rater reliability in both the classic and modified methods, but the inter-rater reliability was higher in the classic method than in the modified method. When categorized according to the sourcil classification, inter-rater reliability was higher in the normal sourcil type and lower in the dysplastic sourcil types.
  
  
  CONCLUSIONS
  Generally, the classic method showed higher reliability than the modified method, even though the reliability of the MI measurement was relatively high with both methods.
authors.affiliation: Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul 120-752, Korea.
authors.forename: Sun Mi
authors.initials: SM
authors.lastname: Kim
authors.forename: Eun Geol
authors.initials: EG
authors.lastname: Sim
authors.forename: Seong Gyu
authors.initials: SG
authors.lastname: Lim
authors.forename: Eun Sook
authors.initials: ES
authors.lastname: Park