Correction of Genu Valgum in Patients With Congenital Fibular Deficiency

Background: Patients with congenital fibular deficiency often develop genu valgum secondary to lateral femoral condylar hypoplasia. Guided growth strategies are often performed to correct limb alignment when adequate skeletal growth remains. Methods: A retrospective review of patients with postaxial hypoplasia of the lower extremity managed with an amputation strategy and who had a guided growth procedure for coronal plane limb malalignment during their course of treatment was performed. Clinical and radiographic data, including measures of coronal plane deformity and alignment, type of amputation, subsequent operative procedures, and complications were recorded. Results: Seventeen patients (20 extremities) met study inclusion criteria (mean follow-up 8.8 y). Foot ablation and hemiepiphysiodesis for valgus deformity of the knee was performed in all extremities. The average age at the time of initial hemiepiphysiodesis was 11.2 years at an average of 8.8 years from the initial amputation procedure. The mean preoperative mechanical axis deviation was 26.5 mm, which was corrected to a mean mechanical axis deviation of 7.0 mm. Fifteen (75%) of the extremities had correction of the deformity to neutral alignment after the initial procedure. Lack of correction occurred in 3 extremities, and overcorrection occurred in 2 extremities. Additional procedures were required in 5 extremities for rebound valgus deformity after hardware removal. Conclusions: In patients with postaxial hypoplasia, regular monitoring of the residual limb for growth-related changes must occur to ensure optimal function and prosthetic fit. Timing of the guided growth procedure is critical, as younger patients may be more likely to experience rebound deformity. Families and patients should be made aware that growth might be unpredictable in this population with risks of both overcorrection and undercorrection.