Abstract
Surfaces are the primary contact zones between a biomaterial and its host organism. Surface treatment or coating provides a means to fulfill demanding structural and mechanical requirements of the prostheses. As well as, a number of studies have been performed on functionally graded materials (FGM) and their suitability for use as the biomaterial of choice in various prostheses. This study investigates the effect of utilizing the two concepts of FGM and coating, in designing new hip stem material. The results of this study concluded that the optimal FGM cemented stem is consisting of titanium at the upper stem layers graded to collagen at lower stem layers. The optimal functionally graded stem coated with collagen reduced the stress shielding by 51 % compared to homogenous titanium stem coated with collagen. However, this optimal graded stem coated with hydroxyapatite showed a reduction of stress shielding by 57 % compared to homogenous titanium stem coated with hydroxyapatite.