Treatment of knee flexion contractures in patients with arthrogryposis

Knee flexion contractures in children with arthrogryposis are difficult to treat. The purpose of this study was to assess the effectiveness of posterior knee releases and gradual contracture distraction with an Ilizarov external fixator in correcting and maintaining correction of knee flexion contractures of 40 degrees or greater.

The medical records and radiographs of 7 consecutive pediatric patients (10 knees) with arthrogryposis and knee flexion contractures of 40 degrees or greater were reviewed. The mean age at surgery was 7.3 years, and the mean length of follow-up was 52.7 months. All patients' knee flexion contractures were treated with posterior soft tissue releases and an Ilizarov external fixator for gradual contracture distraction. Posterior soft tissue releases included hamstrings lengthenings, proximal gastrocnemius release, and release of posterior capsule.

The mean total fixator time was 102 days, with a mean correction rate of 1 degree per day. The mean knee flexion contracture was 72.5 degrees preoperatively, and all knees were corrected to full extension, +/-5 degrees. At latest follow-up, the mean contracture was 20.5 degrees, and all knees were ligamentously stable. The mean total arc of motion was 56 degrees preoperatively and 54 degrees at follow-up. Five patients who were previously nonambulatory became ambulatory. Complications included 3 fractures, 2 posterior tibial subluxations requiring frame adjustment, and 3 contracture recurrences (1 in a patient with a popliteal pterygium).

Posterior knee releases and flexion contracture distraction by Ilizarov fixator was effective in improving the mobility of pediatric patients with arthrogryposis. At follow-up, the gradual loss of correction that occurred did not impact on the ambulatory gains made.