Anterior distal femoral stapling for correcting knee flexion contracture in children with arthrogryposis-preliminary results

Background: Fixed flexion contractures of the knee are more common and disabling than extension contractures in children with arthrogryposis. For correcting these deformities, there are various surgical options such as soft tissue release, distal femoral osteotomy, and frame distraction. We sought in this study to examine the effectiveness of anterior distal femoral stapling using 8-plates for correcting knee flexion contracture in children with arthrogryposis. Methods: We retrospectively assessed 16 knees in 10 children using clinical and radiographic measures. To determine the outcome, we assessed the Functional Mobility Scale (FMS) as well. Statistically, a paired t test, independent t test, and Wilcoxon signed-rank test were used to analyze the results. Results: After anterior distal femoral stapling, there was a reduction in the flexion deformity of the knee in children with arthrogryposis, P<0.05. There was an estimated 18-degree correction comparing the mean preoperative flexion deformity and the mean postoperative flexion deformity. This correction was significant in children when the knee flexion deformity was less than 45 degrees. The FMS also improved in those patients where the residual flexion contracture was less than 30 degrees at follow-up, suggesting an improvement in their ambulatory capacity, P<0.05. Conclusion: Among children with arthrogryposis who present with knee flexion contractures, anterior distal femoral stapling with 8-plates improved their flexion deformity and ambulatory capacity. This technique is less invasive than soft tissue releases, distal femoral osteotomy, or frame distraction and is most rewarding in children with arthrogryposis whose flexion contractures is less than 45 degrees.