Objective: To compare the effects of botulinum toxin type A (BTX-A) injection into the hip adductor muscles on hip displacement with soft-tissue surgery and assess the factors related to a favorable outcome after intervention in children with bilateral spastic cerebral palsy (CP).
Design: Retrospective chart review with regard to radiographic findings.
Setting: University hospital.
Participants: Children with CP (N=194).
Interventions: BTX-A injection and soft-tissue surgery into the hip adductor muscles.
Main outcome measure: The Reimers hip migration percentage (MP).
Results: Sixty-nine children did not receive any therapeutic intervention for hip displacement, whereas 60 children underwent soft-tissue surgery and 65 children took BTX-A injection for the spasticity of their hip muscles. MP was measured on each radiograph of the pelvis. The annual change of MP was improved in both the soft-tissue surgery and BTX-A groups, whereas it worsened in the nonintervention group. The annual improvement of MP in the BTX-A group did not differ significantly from that of the soft-tissue surgery group. The improvement in hip displacement after therapeutic intervention was greater in young children and high-functioning groups compared with older children and low-functioning groups. Hip displacement was progressive in the severely hip subluxated group despite therapeutic intervention.
Conclusions: Comparable effects of BTX-A injection to soft-tissue surgery in our study suggest that BTX-A injection, if timely reinjected, may replace soft-tissue surgery as a prophylactic procedure against progressive hip subluxation or dislocation in children. Age at intervention, functional level, and initial MP before therapeutic intervention were the factors affecting the outcomes.