Distal femoral derotational osteotomy with external fixation for correction of excessive femoral anteversion in patients with cerebral palsy.

Abstract

Patients with cerebral palsy (CP) disorder often develop rotational hip deformity. Increasing deformities impair already diminished walking abilities; femoral osteotomies are often performed to maintain and improve walking abilities. Fixation of osteotomies with condylar plates has been used successfully, but does not often enable immediate postoperative full weight-bearing. To avoid considerable postoperative rehabilitation deficit and additional bone loss because of inactivity, a postoperative treatment with full weight-bearing, is therefore, desirable. Self-tapping Schanz screws with a unilateral external fixator crossing the knee joint providing stronger anchoring in osteopenic bone might fulfill these demands. A retrospective study was carried out on 27 ambulatory CP patients, mean age 17.5 years (range 9-22 years); 11 patients with bilateral severe intoeing deformities underwent a supracondylar femoral osteotomy between September 2008 and April 2012. All patients were allowed to bear their full weight postoperatively. The aim of this study was to describe the technique, the results of this technique, to evaluate the time required for bone healing, and the type of complications associated with a distal derotational femoral osteotomy fixed with a uniaxial external fixator crossing the knee joint. A total of 27 patients were studied [mean weight 48.8 kg (range 29.8-75 kg)]. The mean preoperative rotation included internal rotation of 69° and external rotation of 17°. All patients were evaluated clinically and radiographically for a minimum of 1 year after surgery. There was a significant decrease in the mean medial rotation from 69° to 32° (P=0.00034). The lateral rotation increased significantly from preoperative 17° to postoperative 45° (P=0.0011). The femoral anteversion decreased significantly from a mean of 55° preoperatively to a mean 17° postoperatively (P=0.030). All patients, except one, achieved solid fusion uneventfully. One patient was a 16-year-old female who had sustained a knee flexion contracture of 30° because of a delay in the physiotherapy program. One 13-year-old female patient with a bilateral osteotomy had a nondisplaced fracture in her right femur after a direct trauma 2 weeks after removal of an external fixator, and was treated by a cast. Another 17-year-old male patient developed a nonunion because of loosening of two pins and achieved solid union after revision by dynamic compression plate plating. Besides four cases with superficial pin-tract infection, no other complications were documented. Minimally invasive supracondylar femoral derotational osteotomy fixed with a unilateral external fixators crossing the knee joint is a reliable procedure in CP patients. Most patients can be treated with early postoperative full weight-bearing. However, removal of the knee joint crossing fixator should be performed as early as possible to achieve a full range of motion.