CEREBRAL PALSY HIP DYSPLASIA; A FEMORAL VARUS, SHORTENING, AND MEDIAL DISPLACEMENT OSTEOTOMY USING COMPRESSION HIP SCREWS

Abstract

Hip dysplasia in cerebral palsy (CP) poses technical challenges because of the need to produce large corrections in the face of soft tissue contractures, and extreme distortion of the femur and acetabulum. In addition to adductor and flexor lengthenings, bony surgery may be required in the older child. We have developed an inter-trochanteric shortening osteotomy which allows a major varus realignment without resulting in an adducted leg. Medial displacement of the lower femoral shaft is carried out. The osteotomy is fixed using a Richards Intermediate Hip Screw, whose lag screw and barrel are inserted into the upper face of the osteotomy (not through the lateral cortex as in the standard technique). The plate is attached to the femur below in the normal way. The plate is not prominent laterally because of the medial displacement.

We have performed 37 such osteotomies in 29 patients.19 were male, 18 were female. Age range 3–12 years, mean 8 years. Mean time since operation 5.8 years. Additional procedures were carried out in 16 patients. The mean neck shaft angle pre-operatively was 159 degrees, post-operatively it was 118 degrees. The mean change was 41 degrees. The mean migration percentage pre-operatively was 56.8%, post-operatively it was 15.7%. The mean change was 41.1%. We found the technique to be easier, more stable, and obtained better correction screw did not seem to be a problem, we think because the osteotomy is above the than conventional femoral osteotomy. Rotation of the upper segment around the psoas attachment, and psoas is released.