Anterior femoral epiphysiodesis for the treatment of fixed knee flexion deformity in spina bifida patients

Abstract

Background: Fixed knee flexion deformity is a common problem in spina bifida patients. Owing to interference with ambulation, this deformity may lead to anterior knee pain and progressive crouch gait. If conservative treatment fails, surgical procedures including supracondylar femoral extension osteotomy, joint distraction, and posterior capsulotomy have to be considered. Potential complications of these procedures are fractures, neurovascular lesions, knee instability, and recurrent deformity with continued growth. As fixed knee flexion deformity in spina bifida patients frequently occurs bilaterally, this results in higher perioperative and postoperative risks and prolonged recovery, making these relatively invasive methods less appealing. In the skeletal immature patient, anterior femoral stapling is a feasible method to treat fixed knee flexion deformity as could be shown in an earlier study. In this study, anterior femoral stapling was performed in a series of patients with diverse etiologies, and the overall success rate was then calculated. The aim of this study was to determine whether anterior femoral epiphysiodesis may improve fixed knee flexion deformity in a group of spina bifida patients.

Methods: Ten spina bifida patients with bilateral fixed knee flexion deformity (20 knees) were treated by anterior femoral epiphysiodesis through stapling. None of the patients received further knee procedures. The mean preoperative fixed knee flexion deformity was 20.3 ± 9.9 degrees (range: 10 to 40 degrees). Clinical and radiographic follow-up examinations were performed every 3 to 6 months after surgery.

Results: All patients except 1 experienced significant improvement with a mean correction rate of 0.9 ± 0.5 degrees per month (range: 0.2 to 1.9 degrees). The residual flexion deformity averaged 5.3 ± 5.3 degrees (range: 0 to 15 degrees; P<0.001).

Conclusions: Anterior femoral epiphysiodesis through stapling is an effective and safe method for the treatment of fixed knee flexion deformity in growing children and adolescents with spina bifida.

Level of evidence: Therapeutic Study, Level IV.