Long-Term Outcomes of Hip Interventions for Children With Cerebral Palsy

Background: Children with severe cerebral palsy (CP) are at high risk for progressive hip displacement, associated with pain and contractures interfering with many aspects of care, comfort and quality of life. These children undergo many types of interventions, the optimal timing and effectiveness of which, remain unclear. In 2014, CIHR funded the CP Hip Outcomes Project (CHOP), an international multi-centre prospective longitudinal cohort study of children with severe (non-ambulant) CP with evidence of hip displacement defined as a Reimer's migration percentage (MP) of at least 30%. The study was designed to evaluate the comparative effectiveness of different treatment strategies to prevent or relieve symptoms associated with hip instability, using the validated Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD ) questionnaire as the primary outcome measure of health-related quality of life © (HRQL) for this population. 650 patients enrolled from 28 sites in 11 countries, are actively being followed and will reach at least 2 years of follow-up at the end of 2019. This project, unique in scale and design, will study the impact of hip instability and its management in children with severe CP using a meaningful outcome measure that was developed specifically for this purpose. Although CHOP will define outcomes at 24 months, the outcomes are not expected to remain stable while the child is still growing. The inception cohort will need follow-up until skeletal maturity to track their long-term outcome trajectories. The international network of investigators/sites and the infrastructure established for CHOP will facilitate the long-term follow-up of the participants in this study. In addition, the results of CHOP will inform the design of nested trials to evaluate the effectiveness of future interventions aimed at improving the quality of life of children with severe disabilities.

Study Aims Aim 1: Measure the post 24-month effectiveness of different treatment strategies for hip displacement in children with severe CP using the CPCHILD as the primary outcome measure.

Aim 2: Compare the rates of recurrence, relapse of symptoms, additional interventions and other longer term complications associated with each of the treatment cohorts.

Methods

Study Design: Multi-centre longitudinal cohort study of children with severe (non-ambulant) CP, ages 3 to 18 years with hip MP ≥ 30% enrolled in one of 5 cohorts:

1. "Natural" History or watchful waiting B. Serial botulinum toxin injections C. Adductor (+/- psoas) muscle releases alone D. Hip reconstructive surgery E. Salvage hip surgery Data collected include demographics, prognostic factors, including co-morbid conditions, parental reports of HRQL as measured by the CPCHILD, and radiographic measures of MP and acetabular index (AI). The primary outcome measure CPCHILD, as well as the MP \& AI will be assessed every 12 months after the 24 month follow-up since inception in CHOP. The cohort of 650 children enrolled in Groups B, C, D, \& E will be compared with each other as well as with their respective propensity matched counterparts of untreated children (Group A), using repeated measures ANOCOVA at 3yrs, and annually thereafter until at least 5 years of follow-up or skeletal maturity.

Significance: CHOP I \& II will establish the superiority of either prophylactic or reactive intervention strategies for hip displacement in severe CP and provide justification for hip surveillance.