Late Hip Displacement Identified in Children at Gross Motor Function Classification System II and III With Asymmetric Diplegia and Fixed Pelvic Obliquity.

Risk of hip displacement in children with cerebral palsy is directly related to a child's level of motor function as classified by the Gross Motor Function Classification System (GMFCS) and is reported to be greatest at a young age. In this study, we present a series of four children with asymmetric diplegic cerebral palsy at GMFCS levels II and III, with the more involved hip showing rapid, progressive displacement at a later age. Current hip surveillance guidelines may not adequately identify hip displacement in children with asymmetric diplegia and pelvic obliquity; modifications to surveillance guidelines may be warranted. Additional investigation of hip displacement in this subset of children is required to determine whether the incidence of displacement is higher than anticipated based on the GMFCS level alone.