The effect of coronal femoral bowing on total knee arthroplasty

Abstract

Introduction: Most total knee arthroplasty (TKA) instrumentation systems were designed based on Caucasian anatomy instead of Asian. Coronal femoral bowing is a common extra-articular deformity in Asians. However, whether it is necessary to correct femoral bowing before TKA is controversial. Materials and Methods: Important parameters related to TKA (femoral bowing angle, mechanical lateral distal femoral angle, mechanical medial proximal tibial angle, joint line obliquity, mechanical tibiofemoral angle and valgus correction angle) were measured on the radiographs of 422 lower limbs in 358 patients. We analysed their distributions and correlations, then comparing the accuracy of restoration of the mechanical alignment with different choices of distal femoral resection angle (fixed or patient-specific). Results: Up to 19.9% of Asian patients undergone TKA had severe coronal femoral bowing. There was no statistically significant correlation between FBA and other radiographic parameters, except for VCA (r=0.711, p<0.001). Using patientspecific resection angle during TKA provides significantly higher accuracy in terms of restoring neutral lower limb alignment than fixed resection angle (p<0.001). Discussion and Conclusion: Even if conventional TKA is quite enough to obtain accuracy restoration of mechanical alignment, even without femoral bowing correction, surgeons should pay attention to coronal femoral bowing in patients undergoing TKA. Accurate preoperative measurement and a patient-specific resection angle should be used, which is especially important in patients with severe femoral bowing.