The associated effects of untreated unilateral hip dislocation in cerebral palsy scoliosis

The presence of a unilateral hip dislocation 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 (PO), and scoliosis. The effect of an untreated unilateral hip dislocation on the rate of curve progression of CP scoliosis has not been defined in the literature. The purpose of this study is to investigate the effect of unilateral hip dislocation on PO and the rate of curve progression in children with spastic quadriplegic CP.

Patients with spastic quadriplegic CP who had spine radiographs at the time of initial presentation with scoliosis and at the latest follow-up were evaluated. Twenty-three children with spastic CP who had an untreated unilateral hip dislocation 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 PO, and the rate of PO progression at follow-up were compared between the 2 groups.

The mean ages of patients with a unilateral dislocation and with well-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 unilateral hip dislocation was 12.9 degrees per year. In the control group, the mean progression rate was 12.2 degrees per year. The incidence of PO at follow-up was 74% in scoliotic patients with a dislocation and 63% in scoliotic patients with normal hips. Using repeated-measures analysis of variance, unilateral hip dislocation was found to have no significant effect on scoliosis progression; however, progression of PO 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 the hip(s) at the same surgery.

Unilateral hip dislocation causes a significant increase of PO but does not affect the rate of scoliosis curve progression.