Material selection in the design of the tibia tray component of cemented artificial knee using finite element method

Aseptic loosening of the tibial component; which may be caused by mechanical stress shielding in the bone and may require revision surgery; is the primary concern of total knee replacement (TKR). The stiffness of the implant material had a marked influence on the stresses developed in the constituents and surrounding bones of the artificial knee and then will affect the bone stress shielding. Therefore, the functionally graded materials had been developed as a potential tibia tray material of TKR due to its improved capability of stress distribution. In the current investigation two dimensional finite element models have been developed to study bone and interface stresses for six different tibial prothesises (titanium, CoCrMo and four functional graded materials “FGM” models). The utilization of FGM tibia tray with elastic modulus changing gradually in vertical direction downwardly showed a favorable stress distribution outcome. Furthermore, the results has revealed that the FGM tibia tray will reduce the stress shielding in the surrounding bones of the artificial knee which will increase the life of the total knee prosthesis.