Ambulation gains after knee surgery in children with arthrogryposis.

BACKGROUND: Arthrogryposis multiplex congenita is a rare congenital disorder associated with multiple musculoskeletal contractures that 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 pediatric 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 supracondylar extension osteotomy and/or Ilizarov external fixator, on the ambulation status of children with knee flexion contracture and whether any functional gains are maintained at the latest follow-up.

METHODS: All children with arthrogryposis followed at our institution who had surgical correction for knee flexion contractures were included in this study. Fourteen patients were identified and their medical records were reviewed. The etiology for all patients was amyoplasia. The mean age at first surgery was 7.0 years (range, 2 to 16 y). The mean length of follow-up was 59.3 months (range, 12 to 117 mo). Contractures were treated with femoral extension osteotomy (n=8), Ilizarov external fixator (n=1), or both (n=5). Three patients earlier had posterior soft tissue releases, including hamstrings lengthenings, proximal gastrocnemius release, and release of posterior capsule.

RESULTS: Preoperatively, 11 patients were nonambulatory, 2 patients were household ambulators, and 1 patient walked with orthoses in the community. There was an average of 1.8 knee surgeries done per patient, namely distal femoral extension osteotomy and/or Ilizarov external fixator. At the latest follow-up, 8 patients were ambulatory with technical aids (orthosis, walker, braces, or rollator walker), 2 patients were household ambulators, 1 patient used a wheelchair but was independent for transfers, and 3 patients remained nonambulatory. The mean flexion contracture before the first surgery was 63.7 ± 26.8 degrees. Postoperatively, the mean flexion contracture was 13.2 ± 16.7 degrees. At the latest follow-up, the mean flexion contracture was 34.0 ± 24.1 degrees. There were complications in 2 patients, including infected hardware which resolved with antibiotic treatment, and neurologic compromise which resolved on its own.

CONCLUSIONS: 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 and the recurrence of knee flexion contractures did not limit the ambulatory gains achieved.

LEVEL OF EVIDENCE: IV, Case series.