Improving the performance of cementless knee prosthesis coating through functionally graded material

Surfaces are the primary place of contact a biomaterial and its host organism. Surface treatment or coating provides means to overcome the problem which appeared after knee replacement surgery. There are two main problems: stress shielding and subsequent bone remodeling cause bone resorption around the implant especially at the proximal part of the knee under the tibia tray. The other problem is stem tip pain. Therefore, the aim of this investigation is to find a new design of coating material of a cementless total knee replacement using functionally graded material (FGM). In particular, the objective of this research is to find the optimal material compositions as well as the optimal gradation direction. It has been found that using both vertical and horizontal FGM coatings increased the von Mises stress at the proximal part of the tibial cancellous bone. The von Mises stress in cancellous epiphyseal bone was increased by 77 % using vertical and horizontal FGM coating compared to HAP coating. It has been determined that this new coating design will improve the performance of a cementless tibia tray and will increase the life of the knee prosthesis.