Postoperative heterotopic ossification in children: a comparison of children with spina bifida and with cerebral palsy.

The authors reviewed 250 consecutive myotomies and tenotomies performed on the hips of 186 children. Two groups were studied: 162 children with cerebral palsy and 24 children with spina bifida. In total 19 children were found to have heterotopic ossification postoperatively. The incidence of heterotopic ossification was 21% in the spina bifida group and 8.6% in the cerebral palsy group. The most severe cases were in children with thoracic myelomeningocele. Only one child with lumbar myelomeningocele had ossification, and it was mild. This difference was statistically significant. Two children with thoracic spina bifida had severe ossification and abduction contractures requiring resection of the bony mass. Recurrence was successfully prevented by a course of radiotherapy.