Analysis of the shape of the tibial tray in total knee arthroplasty using a three dimension finite element model

Objective and design. The purpose of this study was to evaluate whether the stress and displacement change with differing shapes of the tibial component in total knee arthroplasty. Background. There are few reports on tibial tray mechanics with and without a posterior concave slot, using three-dimensional finite element analysis. Methods. By considering two different shapes for the tibial component, we analyzed the von Mises stresses and displacements at the component/bone interface and surrounding bone using a three-dimensional finite element model. Results. There was no difference between the two designs in regards to the von Mises stress fields or displacements. The displacement of the tibial tray with a posterior concave slot was less than that of the tray without one in some of the loading configurations. The posterior concave slot appears to reduce the micromotion of the tibial component. Discussion and conclusion. Overall, this finite element analysis showed little difference between the two different types of tibial base plates used with both posterior cruciate ligament retention and substitution. The results of this finite element model analysis do not support the use of tibial base plates without a posterior cut-out slot.