External rotation osteotomy of femur in patients with spastic cerebral palsy

Fifteen subjects with ambulatory spastic cerebral palsy underwent proximal femoral external rotation osteotomy between 1990 to 1992 for severe intoeing gait due to internal femoral torsion. Among them 13 patients returned for follow-up. Preoperatively, maximum internal rotation of the hip on physical examination corrected from 77° to 50° postoperatively. Foot progression angle changed from 10° intoeing gait preoperatively to 9° outtoeing gait postoperatively (p<0.05). The recurrence rate for internal femoral torsion after correction is 9.5 degrees/year for the group of 10-year-olds and younger, and 2.1 degrees/year for the group older than 10-year-olds. In the kinematic study, foot progression angle changed from internal rotation of 9.2° to external rotation of 16.5° (p<0.05). Our study showed that external rotation osteotomy of the femur is a safe and effective procedure. The rate of recurrence for femoral internal torsion was greater for younger patients (≤10-year-old) when the surgery was performed.