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3D ultrasound to quantify lateral hip displacement in children with cerebral palsy: a validation study

Research output: Contribution to journalArticlepeer-review

Rebecca H. Kay, Jonathan J. Noble, Liam Johnston, Stephen F. Keevil, Michail Kokkinakis, Daniel Reed, Martin Gough, Adam P. Shortland

Original languageEnglish
Pages (from-to)1389-1395
Number of pages7
JournalDevelopmental Medicine and Child Neurology
Issue number12
Accepted/In press1 Jan 2020
Published1 Dec 2020

King's Authors


Aim: To assess the validity of a new index, lateral head coverage (LHC), for describing hip dysplasia in a population of children with cerebral palsy (CP). Method: LHC is derived from 3D ultrasound assessment. Twenty-two children (15 males, seven females; age 4–15y) with CP undergoing routine hip surveillance were recruited prospectively for the study. Each participant had both a planar radiograph acquired as part of their routine care and a 3D ultrasound assessment within 2 months. Reimer's migration percentage (RMP) and LHC were measured by the same assessor, and the correlation between them calculated using Pearson’s correlation coefficient. The repeatability of LHC was investigated with three assessors, analysing each of 10 images three times. Inter- and intra-assessor variation was quantified using intraclass correlation coefficients. Results: LHC was strongly correlated with RMP (Spearman's rank correlation coefficient=−0.86, p<0.001). LHC had similar inter-assessor reliability to that reported for RMP (intraclass correlation coefficient=0.97 and intra-assessor intraclass correlation coefficient=0.98). Interpretation: This is an initial validation of the use of 3D ultrasound in monitoring hip development in children with CP. LHC is comparable with RMP in estimating hip dysplasia with similar levels of reliability that are reported for RMP.

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