Hip Problems in Children with Cerebral Palsy: An Overview

Abstract

Children with cerebral palsy often develop subluxation or dislocation. It occurs most commonly in children aged 2–8 years but may occur until skeletal maturity. It is usually caused by abnormally strong or spastic pull of the adductor and hip flexor muscles which causes the femur to position in internal rotation, flexion, and adduction. Early identification with yearly hip radiographs which are monitored using the migration percent (MP) will identify the condition early, when treatment has a better outcome. Adductor and flexor muscle lengthening in the young child when the MP is between 25% and 60% has a good chance of resolving the subluxation. For those detected later or failed soft tissue lengthening, hip reconstruction with pelvic and femoral osteotomy usually provides a good outcome. For those hips which develop a complete dislocation and severe arthritis, options for treatment include total hip replacement, interposition arthroplasty, or proximal femoral resection. Although most hips are posterior lateral in the direction of subluxation, it is important to diagnose those which are anterior or due to hypotonia. The treatment for these requires a different approach. Some children may also have developmental hip dislocation (DDH) which tends to respond very differently than CP hip dislocation. In very young children under age 2 years, it is important to determine if the hip displacement is due to DDH or CP spasticity. Complications from treating CP hip displacement include recurrence as the most common complication, followed by wound infection, delayed femoral union, heterotopic ossification, and avascular necrosis.