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The CPUP Hip Score predicts displacement of the hip in children with cerebral palsy

Gaston, Mark S. ; Wordie, Sarah J. ; Wagner, Philippe LU ; Hägglund, Gunnar LU and Robb, James E. (2022) In The Bone & Joint Journal 104-B(5). p.640-644
Abstract

AIMS: The Uppföljningsprogram för cerebral pares (CPUP) Hip Score distinguishes between children with cerebral palsy (CP) at different levels of risk for displacement of the hip. The score was constructed using data from Swedish children with CP, but has not been confirmed in any other population. The aim of this study was to determine the calibration and discriminatory accuracy of this score in children with CP in Scotland. METHODS: This was a total population-based study of children registered with the Cerebral Palsy Integrated Pathway Scotland. Displacement of the hip was defined as a migration percentage (MP) of > 40%. Inclusion criteria were children in Gross Motor Function Classification System (GMFCS) levels III to V. The... (More)

AIMS: The Uppföljningsprogram för cerebral pares (CPUP) Hip Score distinguishes between children with cerebral palsy (CP) at different levels of risk for displacement of the hip. The score was constructed using data from Swedish children with CP, but has not been confirmed in any other population. The aim of this study was to determine the calibration and discriminatory accuracy of this score in children with CP in Scotland. METHODS: This was a total population-based study of children registered with the Cerebral Palsy Integrated Pathway Scotland. Displacement of the hip was defined as a migration percentage (MP) of > 40%. Inclusion criteria were children in Gross Motor Function Classification System (GMFCS) levels III to V. The calibration slope was estimated and Kaplan-Meier curves produced for five strata of CPUP scores to compare the observed with the predicted risk of displacement of the hip at five years. For discriminatory accuracy, the time-dependent area under the receiver operating characteristic curve (AUC) was estimated. In order to analyze differences in the performance of the score between cohorts, score weights, and subsequently the AUC, were re-estimated using the variables of the original score: the child's age at the first examination, GMFCS level, head shaft angle, and MP of the worst hip in a logistic regression with imputation of outcomes for those with incomplete follow-up. RESULTS: The discriminatory accuracy of the score in the new population of 367 children was high (AUC 0.78 (95% confidence interval (CI) 0.71 to 0.86)). The calibration of the score was insufficient (slope 0.48 (95% CI 0.31 to 0.65)), and the absolute risks of displacement of the hip in this population were overestimated. The AUC increased with re-estimated weights (0.85 (95% CI 0.79 to 0.91)). CONCLUSION: The CPUP Hip Score had a high ability to discriminate between children at different levels of risk for displacement of the hip. The score overestimated the absolute risks of displacement in this population, which may have resulted from differences in the way children were initially registered in the two programmes. The results are promising, but the score weights may need re-estimation before its clinical application in Scotland. Cite this article: Bone Joint J 2022;104-B(5):640-644.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cerebral palsy, cerebral palsy, CPUP Hip Score, dislocation of the hip, femoral head, Gross Motor Function Classification System, Hip displacement, Hip Score, hips, Kaplan-Meier curves, logistic regression analysis, orthopaedic surgeons, radiography
in
The Bone & Joint Journal
volume
104-B
issue
5
pages
5 pages
publisher
British Editorial Society of Bone & Joint Surgery
external identifiers
  • scopus:85129781009
  • pmid:35491586
ISSN
2049-4408
DOI
10.1302/0301-620X.104B5.BJJ-2021-0301.R5
language
English
LU publication?
yes
id
3a3a2f28-8346-4d17-893a-344c7186544d
date added to LUP
2022-08-25 10:50:09
date last changed
2024-04-30 05:06:54
@article{3a3a2f28-8346-4d17-893a-344c7186544d,
  abstract     = {{<p>AIMS: The Uppföljningsprogram för cerebral pares (CPUP) Hip Score distinguishes between children with cerebral palsy (CP) at different levels of risk for displacement of the hip. The score was constructed using data from Swedish children with CP, but has not been confirmed in any other population. The aim of this study was to determine the calibration and discriminatory accuracy of this score in children with CP in Scotland. METHODS: This was a total population-based study of children registered with the Cerebral Palsy Integrated Pathway Scotland. Displacement of the hip was defined as a migration percentage (MP) of &gt; 40%. Inclusion criteria were children in Gross Motor Function Classification System (GMFCS) levels III to V. The calibration slope was estimated and Kaplan-Meier curves produced for five strata of CPUP scores to compare the observed with the predicted risk of displacement of the hip at five years. For discriminatory accuracy, the time-dependent area under the receiver operating characteristic curve (AUC) was estimated. In order to analyze differences in the performance of the score between cohorts, score weights, and subsequently the AUC, were re-estimated using the variables of the original score: the child's age at the first examination, GMFCS level, head shaft angle, and MP of the worst hip in a logistic regression with imputation of outcomes for those with incomplete follow-up. RESULTS: The discriminatory accuracy of the score in the new population of 367 children was high (AUC 0.78 (95% confidence interval (CI) 0.71 to 0.86)). The calibration of the score was insufficient (slope 0.48 (95% CI 0.31 to 0.65)), and the absolute risks of displacement of the hip in this population were overestimated. The AUC increased with re-estimated weights (0.85 (95% CI 0.79 to 0.91)). CONCLUSION: The CPUP Hip Score had a high ability to discriminate between children at different levels of risk for displacement of the hip. The score overestimated the absolute risks of displacement in this population, which may have resulted from differences in the way children were initially registered in the two programmes. The results are promising, but the score weights may need re-estimation before its clinical application in Scotland. Cite this article: Bone Joint J 2022;104-B(5):640-644.</p>}},
  author       = {{Gaston, Mark S. and Wordie, Sarah J. and Wagner, Philippe and Hägglund, Gunnar and Robb, James E.}},
  issn         = {{2049-4408}},
  keywords     = {{Cerebral palsy; cerebral palsy; CPUP Hip Score; dislocation of the hip; femoral head; Gross Motor Function Classification System; Hip displacement; Hip Score; hips; Kaplan-Meier curves; logistic regression analysis; orthopaedic surgeons; radiography}},
  language     = {{eng}},
  number       = {{5}},
  pages        = {{640--644}},
  publisher    = {{British Editorial Society of Bone & Joint Surgery}},
  series       = {{The Bone & Joint Journal}},
  title        = {{The CPUP Hip Score predicts displacement of the hip in children with cerebral palsy}},
  url          = {{http://dx.doi.org/10.1302/0301-620X.104B5.BJJ-2021-0301.R5}},
  doi          = {{10.1302/0301-620X.104B5.BJJ-2021-0301.R5}},
  volume       = {{104-B}},
  year         = {{2022}},
}