Journal of Pediatric Orthopaedics - 2026-06-26 - Journal Article
Characteristics of Hip Dysplasia in Adults With Cerebral Palsy.
Sugiyama T, Hurvitz EA
Topics
Key Takeaway
In 331 adults with CP, 24.5% had hip subluxation (MP>30%), with GMFCS IV/V showing the highest displacement (PE=16.29 and 14.20 respectively), but 21.6% of GMFCS I/II adults were MCHCS grade 4 or higher.
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Summary
This retrospective study quantified hip dysplasia prevalence and severity in adults with CP (≥18 years) using migration percentage and the Melbourne Cerebral Palsy Hip Classification System across 331 patients stratified by GMFCS level. GMFCS IV and V were the strongest predictors of displacement (PE=16.29 and 14.20, p<0.01), but GMFCS I/II showed progressive MP increase with age (PE=0.10, p=0.046), a finding absent in higher GMFCS groups. The data establish that hip dysplasia is not a resolved pediatric problem—24.5% of the adult cohort had subluxation and 21.6% of ambulatory adults (GMFCS I/II) had severe MCHCS grading.
Key Limitation
Cross-sectional design cannot establish whether hip displacement in GMFCS I/II adults is progressive or was present but undetected at skeletal maturity, which is essential before recommending adult surveillance protocols.
Original Abstract
BACKGROUND
With increased life expectancy, cerebral palsy (CP) is no longer solely a pediatric condition. Among adults with CP, orthopaedic conditions and associated pain represent the most prevalent challenges. Hip dysplasia is one of the most common conditions affecting adults with CP; however, the research remains limited, and clear follow-up guidelines are currently lacking. This study aimed to investigate the prevalence and severity of hip dysplasia in adults with CP and identify related factors. Our goal is to create a foundation for developing follow-up methods and clinical screening for specific groups of adults with CP at risk for worsening hip dysplasia.
METHODS
This retrospective study examined hip radiographs of 331 adults with CP (aged 18 y or older) from (removed for blinding) between 2011 and 2021. Migration percentage (MP) and Melbourne Cerebral Palsy Hip Classification System (MCHCS) were used to assess hip displacement. Patient factors, including age, sex, Gross Motor Function Classification System (GMFCS) level, pain condition and treatment, and spasticity management were analyzed. Linear regression models examined associations between patient factors and MP, while ordered logistic regression assessed relationships between GMFCS and MCHCS.
RESULTS
The mean MP across all participants was 23.2% (SD: 15.3), with 24.5% showing hip subluxation (MP>30%). GMFCS level was strongly associated with hip displacement, with GMFCS IV and V showing significantly higher MP values (Parameter Estimate=16.29 and PE=14.20, respectively; both P<0.01). Among GMFCS I/II, MP increased with age (PE=0.10, P=0.046), while no significant age associations were found in other GMFCS groups. MCHCS was also associated with GMFCS level, especially GMFCS IV and V (both P <0.0001). Notably, 21.6% of GMFCS I/II subjects were MCHCS 4 or higher.
CONCLUSIONS
Hip dysplasia remains prevalent in adults with CP, with GMFCS level being the strongest predictor of displacement severity. Those with GMFCS I/II may experience progressive displacement with aging, while severe displacement in higher GMFCS levels may develop earlier. These findings emphasize the potential importance of understanding the natural history of the hip in CP into adulthood for all GMFCS levels.
LEVEL OF EVIDENCE
Prognostic study level II-retrospective study.