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Risk factors for hip displacement in cerebral palsy: A population-based study of 121 nonambulatory children
Terje Terjesen1, Joachim Horn1
1Division of Orthopaedic Surgery, Oslo University Hospital, Rikshospitalet, University of Oslo, Oslo, Norway.
Insights
Initial hip migration percentage and its rate of progression are key indicators for hip subluxation in young children with cerebral palsy (CP). Monitoring these factors aids in early detection and management of hip displacement in nonambulatory CP patients.
Area of Science:
- Pediatric Orthopedics
- Cerebral Palsy Research
- Hip Development
Background:
- Hip subluxation is a common complication in nonambulatory children with cerebral palsy (CP).
- Early identification of risk factors is crucial for timely intervention to prevent severe hip displacement.
- Hip surveillance programs aim to monitor hip development and detect abnormalities in at-risk pediatric populations.
Purpose of the Study:
- To identify independent clinical and radiographic risk factors for hip subluxation in nonambulatory children under 5 years old with cerebral palsy.
- To determine which variables predict the development or progression of hip displacement in this vulnerable group.
Main Methods:
- A cohort of 121 nonambulatory children (aged 0.7-4.9 years) with cerebral palsy (Gross Motor Function Classification System levels III-V) were analyzed.
- Hip radiographs were assessed for migration percentage and acetabular index.
- Univariable and multivariable regression analyses were performed to identify independent risk factors for hip subluxation.
Main Results:
- At follow-up, 67 children (55%) had significant hip displacement (migration percentage ≥40%).
- Independent risk factors for hip subluxation in children with initial migration percentage <50% were initial migration percentage (p=0.003) and yearly rate of migration percentage progression (p<0.001).
Conclusions:
- Initial migration percentage and the rate of migration percentage progression are critical parameters for hip surveillance in young children with cerebral palsy.
- Acetabular index and femoral head-shaft angle may assist in treatment decisions later in the management process.
Purpose:
The aim was to evaluate which clinical and radiographic variables are independent (true) risk factors for hip subluxation in nonambulatory children below 5 years of age with cerebral palsy.
Methods:
Patients were recruited from a population-based hip surveillance program. Inclusion criteria were birth during 2002-2006, age below 5 years, and gross motor function classification system levels III-V. In all, 121 children (71 boys) met these criteria. Gross motor function classification system was level III in 29 patients, level IV in 28, and level V in 64. Anteroposterior radiographs at diagnosis and during follow-up were assessed, and only the worst hip of each patient was used for the analyses. The mean age at the initial radiograph was 2.5 years (range: 0.7-4.9 years), and the mean follow-up time was 4.0 years (range: 0.5-11.8 years).
Results:
At the last follow-up, 67 children had a clinically significant hip displacement, defined as migration percentage ≥40%. Univariable regression analysis defined these risk factors: gross motor function classification system level V, spastic bilateral cerebral palsy, initial migration percentage, yearly rate of migration percentage progression, and initial acetabular index. When these variables were analyzed with multivariable regression in 107 patients with initial migration percentage <50% and follow-up ≥1.0 year, the independent risk factors were initial migration percentage (p = 0.003) and yearly rate of migration percentage progression (p < 0.001).
Conclusion:
The parameters that need to be assessed in hip surveillance in children below 5 years of age are initial migration percentage and rate of migration percentage progression. Acetabular index and femoral head-shaft angle might be useful later for decision-making regarding choice of treatment.
Level Of Evidence:
Level II, development of diagnostic criteria.
