Biomechanical finite element analysis of various tibial plateau posterior tilt angles in medial unicondylar knee arthroplasty.

The present study aimed to determine the optimal posterior tibial plateau inclination for fixed-platform unicondylar knee arthroplasty (UKA) using finite element analysis (FEA). These findings provided a theoretical basis for selecting an appropriate posterior inclination of the tibial plateau during surgery. The present study utilized the FEA method to create models of fixed-platform UKA with tibial plateau posterior inclinations of 3, 6 and 9˚. The stress changes in the internal structures of each model after knee flexion motion were then compared. During knee flexion from 0 to 90˚, the contact and Von Mises equivalent stresses of the femoral condyle prosthesis and tibial platform pad revealed consistent trends of 3˚ posterior inclination, >6˚ posterior inclination and >9˚ posterior inclination. The present study established the first quasi-dynamic fixed-platform UKA model of the knee joint under load-bearing conditions. From a theoretical perspective, it was found that controlling the posterior inclination of UKA between 6 and 9˚ may be more beneficial for the survival of the tibial platform pad than between 3 and 6˚. It is also more effective in reducing pad wear.