Correlation between Surface Area Ratio of Medial to Lateral Tibial Plateau and Knee Alignment in Adults

Objective This study aimed to investigate the correlation between the surface area ratio of medial tibial plateau (MTP) to lateral tibial plateau (LTP) and the mechanical tibiofemoral angle (mTFA). Methods Lower limb computed tomography (CT) images were collected at our hospital. Then, the original CT data were analyzed and reconstructed using medical image processing software. The proximal and distal centres of the femur and tibia were marked. The surface areas of MTP and LTP were identified using image processing software. GraphPad Prism 8.0.2 was used to perform the statistical analysis. Results The surface area ratio of MTP to LTP was significantly correlated with the mTFA in all patients (P<0.0001), male group (P<0.0001), female group (P<0.0001), varus group (P<0.0001), and valgus group (P=0.002). Furthermore, the surface area of MTP and LTP was significantly greater in the male group than in the female group (P<0.0001). There was significant difference in the surface area of the MTP between the varus and valgus groups (P<0.0001). Significant difference was also observed in the surface area ratio of MTP to LTP between the varus and valgus groups (P<0.0001). Conclusion The surface area ratio of MTP to LTP was correlated with the mTFA. Within a certain range, the smaller the mTFA, the greater the surface area ratio of MTP to LTP. For patients undergoing total knee arthroplasty, of whom the surface area of the MTP was basically equal to that of the LTP, it is recommended that the osteotomy should be performed in accordance with mechanical alignment standards, and that a symmetrical tibial plateau prosthesis should be used. For patients whose surface area of MTP is significantly greater than that of the LTP, it is recommended that the osteotomy should be performed in accordance with kinematic alignment standards, and that an anatomical tibial plateau prosthesis should be used.