Risk factors for hip displacement in children with cerebral palsy: Systematic review

Background: When hip displacement in children with cerebral palsy (CP) is identified early, treatment is more successful. The standard test is a radiograph of the pelvis measuring the migration index (MI). Our study aims to review published literature of the natural history of hip dislocation among children with CP and to define related risk factors to develop screening criteria for early recognition. Methods: The review included 10 studies with sample sizes greater than 20 children with CP below18 years who had hips with no surgical intervention or dislocation at initial presentation, minimum 2-year follow-up, and recorded MI, pattern, and Gross Motor Function Classification System (GMFCS) level. Results: On the basis of this review, we suggest screening with 1 radiograph for GMFCS I and II, or, if MI > 30%, an annual radiograph between ages 2 and 8 years, followed by a radiograph every 2 years until the age of 18 years. For GMFCS III, IV, and V, we recommend an annual radiograph if MI < 30% or 1 every 6 months if MI > 30% between ages 2 and 8 years, followed by radiograph every 2 years until the age of 18 years. Conclusions: Applying a practical surveillance program for children with CP can prevent hip dislocation, provide early treatment, and ultimately lead to consistently better outcomes than those of neglected hip dislocations. The GMFCS level has a strong impact on subluxation risk and that the risk continues to the end of growth.