[Bone surgery for unstable hips in patients with cerebral palsy]

The aim of this retrospective study was to compare the efficacy of femoral osteotomy alone with that of osteotomy combined with an acetabular procedure in patients with unstable hips due to spastic cerebral palsy.

Sixty-one hip joints in 50 patients who had shown distinct subluxation or dislocation of the joint were operated on. Eleven patients underwent bilateral surgery. Before bone surgery, soft-tissue release involving both the flexors and adductors was performed on 19 hips. Femoral osteotomy alone was performed on 29 hip joints and combined femoral and pelvic osteotomy was carried out on 32 joints.Twelve resections of the proximal femur in seven patients were evaluated as a separate group. All treated hip joints were assessed by clinical and radiographic examination at a follow-up of more than 5 years.

The skiagraphs taken in a strictly neutral position of the lower limbs before surgery and at the final examination were evaluated on the basis of Reimers's migration index and Wiberg's centre-edge angle. The locomotor abilities of each child were categorized according to the Vojta scoring system for locomotor development. The range of motion in the treated hip joint was assessed using the standard S. F. T. R. method. The results obtained were statistically analyzed by the Kruskal- Wallis, one-way ANOVA test.

A comparison of the results of femoral osteotomy alone with those of combined femoral and pelvic osteotomy showed that the post-operative values of the migration index and centre-edge angle, as compared with the pre-operative ones, were statistically higher (p<0.05) in the latter. In a long-term perspective, the surgery had no adverse effects on a natural development of locomotor abilities of the child. The children had higher scores by the modified Vojta rating system. There was no change in the range of motion in the treated hip joints after the operation.

In 28, out of the 32 joints treated by combined femoral and pelvic osteotomy, Salter osteotomy was performed and it showed a high efficacy in providing hip joint stability. The main emphasis during surgery was placed on the maximum acetabular rotation laterally. Femoral osteotomy alone was less effective in providing hip joint stability; in addition, in order to achieve this, tilting of the proximal fragment to a varus position was generally higher than in combined operations. In three patients this treatment resulted in fixed adduction of the hip joint with negative consequences for movement.

In the treatment of unstable hip joints a combination of varus derotation femoral osteotomy and pelvic osteotomy provides better containment of the joint than femoral osteotomy alone.