In 15 patients with cerebral palsy who underwent selective posterior r
hizotomy (SPR) and subsequent proximal femoral varus derotation osteot
omy (VDO), heterotopic ossification (HO) around the hip after VDO was
noted in four of eight patients with spastic quadriplegia (seven of 26
hips, 27%). HO was not noted in the seven patients with spastic diple
gia. A radiographic review of 118 hips with a femoral VDO in the 69 pa
tients with cerebral palsy who did not undergo SPR during the same per
iod showed no HO. Frequent evaluation of post-rhizotomy patients with
cerebral palsy quadriplegia after a femoral VDO is necessary to recogn
ize HO as a possible etiology for late-onset pain and limited hip rang
e of motion (ROM).