Hip displacement, defined in this study as a
migration percentage (MP) of more than 40%, is a common, debilitating complication
of cerebral palsy (CP). In this prospective study we analysed the
risk of developing hip displacement within five years of the first
pelvic radiograph. All children with CP in southern and western Sweden are invited
to register in the hip surveillance programme CPUP. Inclusion criteria
for the two groups in this study were children from the CPUP database
born between 1994 and 2009 with Gross Motor Function Classification
System (GMFCS) III to V. Group 1 included children who developed
hip displacement, group 2 included children who did not develop
hip displacement over a minimum follow-up of five years. A total
of 145 children were included with a mean age at their initial pelvic
radiograph of 3.5 years (0.6 to 9.7). The odds ratio for hip displacement was calculated for GMFCS-level,
age and initial MP and head-shaft angle. A risk score was constructed
with these variables using multiple logistic regression analysis.
The predictive ability of the risk score was evaluated using the
area under the receiver operating characteristics curve (AUC). All variables had a significant effect on the risk of a MP >
40%. The discriminatory accuracy of the CPUP hip score is high (AUC
= 0.87), indicating a high ability to differentiate between high-
and low-risk individuals for hip displacement. The CPUP hip score
may be useful in deciding on further follow-up and treatment in
children with CP. Cite this article:
