Functionally Graded Coating Material of Cementless Knee Prosthesis
Saeed Ahmed Asiri *
Department of Mechanical Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
N. Fouda
Department of Production and Mechanical Design, Faculty of Engineering, Mansoura University, Mansoura, Egypt
H. S. Hedia
Faculty of Maritime Studies, King Abdulaziz University, Jeddah, Saudi Arabia
*Author to whom correspondence should be addressed.
Abstract
Surfaces are the primary place of contact a biomaterial and its host organism. Surface treatment or coating provides a means to overcome the problem which appeared after knee replacement surgery. There are two main problems; the stress shielding and subsequent bone remodeling causes 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). The objective of this research is to find the optimal material compositions, as well as the optimal gradation direction. It is found that using both vertical and horizontal FGM coating increased the von Mises stress at the proximal part of the tibial cancellous bone. Von Mises stress in cancellous epiphyseal bone is increased by 77% using vertical and horizontal FGM coating compared to hidroxyapatite HAP coating. It is found that this new coating design will improve the performance of a cementless tibia tray and will increase the life of the knee prosthesis.
Keywords: Cementless knee replacement, coating material, functionally graded material, von Mises stresses, stress shielding, finite element analysis