Purpose: Arthrogryposis Multiplex Congenita is a rare congenital disorder associated with multiple musculo-skeletal contractures which causes substantial morbidity. Knee involvement is commonly seen among children with arthrogryposis, with flexion contracture of the knee being the most frequent knee deformity. Knee flexion contractures in the paediatric population are particularly debilitating as they affect ambulation. Treatment for knee flexion contractures requires numerous orthopaedic procedures and an extensive follow-up period. The purpose of this study was to assess the effectiveness of orthopaedic procedures, namely distal femoral extension osteotomy and/or Ilizarov external fixator, on the ambulation status of children with knee flexion contracture.

Method: The medical records and radiological images of 16 paediatric patients with arthrogryposis and knee flexion contractures were reviewed. The etiology of all of them was amyoplasia except for one case of popliteal pterygium. The mean age of first surgery was 6.2 years (age range: 1–15 years). The mean length of follow-up was 83.9 months. All patients’ knee flexion contractures were treated with femoral extension osteotomy, Ilizarov external fixator, or both. Two patients previously had posterior soft tissue releases, including hamstrings lengthenings, proximal gastrocnemius release, and release of posterior capsule.

Results: Prior to the initial surgery for knee flexion contracture, 13 patients were non-ambulatory. One patient was a household ambulator with flexed knees. Two patients walked with orthoses. There was an average of 1.8 surgeries done per patient, namely distal femoral extension osteotomy and/or Ilizarov external fixator. At the latest follow-up, 12 patients were ambulatory, including 11 children ambulating with technical aids (orthosis, walker, braces, or rollator walker) and one child ambulating without any technical aid. Four patients remained non-ambulatory. The mean total arc of motion was 64.8 degrees preoperatively, 63.1 degrees postoperatively, and 52.8 degrees at the latest follow-up. A mean loss of 6.8 degrees per year in total arc of motion occurred. There were complications in four patients which consist of infected hardware, transient neurological compromise, cast change, and pressure sore.

Conclusion: Surgical correction of knee flexion deformities by distal femoral extension osteotomy and/or Ilizarov external fixator was effective in improving the ambulation status of children with arthrogryposis. At latest follow-up, the gradual loss of total arc of motion did not impact the ambulatory gains made by these procedures.