Epidemiology of Lower Limb Musculoskeletal Pathology in Cerebral Palsy: A Population-Based, Cohort Study.

Background: Musculoskeletal pathology (MSP) develops in the lower limbs of the majority of children with cerebral palsy (CP) with time and growth. The aims of this study were to investigate the epidemiology of MSP in the lower limbs, of a large population-based sample of children with CP, at long-term follow up. Methods: An inception cohort was generated from the Victorian Cerebral Palsy Register for the birth years 1990 through 1992 inclusive. Children had regular clinical and radiographic examinations from infancy until after skeletal maturity. Cerebral palsy was classified using the Gross Motor Function Classification System (GMFCS) and a Topographical Classification System (TCS), devised for this study. MSP was classified using the Musculoskeletal Pathology Classification System, which has good reliability. Results: A full dataset was available for 292 individuals, 78% of the inception cohort (170 males, 122 females). Mean age at final follow-up was 20 years (SD 4.5, range 6-31 years). MSP type changed with age. Hypertonia (MSP 1) was present in 77% of children at age 5 years, contractures (MSP 2) in 22% of children at 10 years, contractures combined with bony torsion (MSP 3) in 31% of teenagers at age 15 years, and decompensation (MSP 4) in 15% of young adults at age 25 years. There were moderate to strong associations between GMFCS and MSP and TCS and MSP (Kendall's tau 0.36-0.55, p < 0.001). Conclusions: The prevalence of MSP in children with CP who were born between 1990 and 1992 and followed into the third decade was high and was related to age and CP severity by GMFCS. Level of Evidence: Level IV. See Instructions for Authors for a complete description of levels of evidence.