The Associated Effects of Untreated Unilateral Hip Dislocation in Cerebral Palsy Scoliosis

Introduction: The presence of a unilateral hip dislocation (UHD) in children with cerebral palsy (CP) may cause problems with sitting imbalance, pressure ulcers and hip pain. There is a dynamic interplay between hip dislocation, pelvic obliquity and scoliosis, but this is not well defined in the literature. The purpose of this study is to investigate the effect of UHD on pelvic obliquity and the rate of curve progression in children with CP.

Methods: Patients with spastic quadriplegic CP who had adequate spine radiographs were evaluated. Twenty-three children with spastic CP who had an untreated UHD and scoliosis constituted the study group. The control group consisted of 83 quadriplegic CP patients with scoliosis and well located hips. The rate of curve progression, incidence of pelvic obliquity and the rate of pelvic obliquity progression at follow up were compared between the two groups.

Results: The mean age of patients with a UHD and with located hips at initial radiograph were 10.4 and 10.5 years, respectively. The mean follow-up was 3.5 years. The mean rate of scoliosis curve progression in patients with a UHD was 12.9 degrees/year. In the control group, the mean progression was 12.2 degrees/year. The incidence of pelvic obliquity at follow up was 74% in scoliotic patients with a dislocation and 63% in scoliotic patients with normal hips. Using repeated-measures ANOVA, UHD was found to have no significant effect on scoliosis progression; however, progression of pelvic obliquity was significantly increased in the hip dislocation group (p<0 .05). Pelvic obliquity was corrected after posterior spinal fusion to the sacrum with pelvic fixation, without reducing hip(s) at same surgery.

Conclusion: Unilateral hip dislocation causes a significant increase in pelvic obliquity, but does not have an effect on the rate of scoliosis progression.