Inter- and intra-rater reliability of the head-shaft angle in children with cerebral palsy

Research output: Contribution to journalArticle


Purpose. Children with cerebral palsy (CP) are at increased risk for hip dislocation. This can be prevented in most cases using surveillance programmes that include radiographic examinations. Known risk factors for hip dislocation include young age, high Gross Motor Function Classification System (GMFCS) level and high migration percentage (MP). The head-shaft angle (HSA) has recently been described as an additional risk factor. The study aim was to determine inter- and intra-rater reliability of the HSA in a surveillance programme for children with CP. Methods. We included hip radiographs from the CP surveillance programme CPUP in southern Sweden during the first half of 2016. Fifty radiographs were included from children at GMFCS levels II-V, with a mean age of 6.6 (SD 3.2) years. Three raters measured the HSA of one hip (left or right) at baseline and four weeks later; intraclass correlation coefficient (ICC) was used to estimate interand intra-rater reliability. Results. Interand intra-rater reliability were excellent for the HSA, with ICC 0.92 (95% CI 0.87-0.96) and ICC 0.99 (95% CI 0.98-0.99), respectively. Conclusion. The HSA showed excellent interand intra-rater reliability for children with CP, providing further evidence for use of the HSA as an additional factor for identifying risk for further hip displacement or dislocation.


External organisations
  • Skåne University Hospital
  • Skaraborg Hospital
  • Uppsala University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Orthopedics
  • Pediatrics


  • Cerebral palsy, CPUP, CPUP hip score, Head-shaft angle, Hip, Hip displacement, Reliability
Original languageEnglish
Pages (from-to)256-262
Number of pages7
JournalJournal of Children's Orthopaedics
Issue number4
Publication statusPublished - 2017
Publication categoryResearch