Anterior distal femoral hemiepiphysiodesis in the treatment of fixed knee flexion contracture in neuromuscular patients

Aim Patients with neuromuscular diseases such as cerebral palsy (CP) and meningomyelocele (MMC) are prone to develop fixed knee flexion contracture. Distal femoral extension osteotomy allows acute correction of the deformity, but it is an extensive surgical procedure, and the complication rate is rather high. Immobilization can prolong the rehabilitation period, and may even result in deteriorated walking ability. The aim of this retrospective study was to evaluate the results of using anterior hemiepiphysiodesis of the distal femur to treat fixed flexion contracture of the knee. Materials and methods We studied 21 patients in our department from 2003 to 2009. Mean age was 10 years (5-15). Twelve suffered from MMC, five from CP, two from arthrogryposis, one had an enzyme defect, and one had Down's syndrome. Thirteen patients had a bilateral and eight a unilateral procedure. None of the patients underwent any other procedures. Two staples or 8-plates were inserted using two parapatellar incisions. Nine were operated on with staples and 12 with 8-plates. The plates or staples were removed when the desired effect of full knee extension was achieved or the patient reached skeletal maturity. Results Mean fixed flexion contracture was 20 degrees (10 degrees - 40 degrees). Staples or 8-plates were removed after a mean of 24 (6-42) months. Mean fixed flexion contracture at removal was 10 degrees (0 degrees - 30 degrees). Two complications were seen: one infection and one supracondylar fracture. Conclusion Anterior distal femoral hemiepiphysiodesis using 8-plates or staples seems to be effective for correcting fixed knee flexion deformity in skeletally immature individuals. The complication rate is low (10 %). Our results are comparable to those of Kramer, Klatt, and Stevens. This procedure should be the primary treatment for fixed knee flexion contractures in neuromuscular patients with sufficient remaining growth.