Comparison of Various Functionally Graded Femoral Prostheses by Finite Element Analysis

Abstract

This study is focused on finite element analysis of a model comprising femur into which a femoral component of a total hip replacement was implanted. The considered prosthesis is fabricated from a functionally graded material (FGM) comprising a layer of a titanium alloy bonded to a layer of hydroxyapatite. The elastic modulus of the FGM was adjusted in the radial, longitudinal, and longitudinal-radial directions by altering the volume fraction gradient exponent. Four cases were studied, involving two different methods of anchoring the prosthesis to the spongy bone and two cases of applied loading. The results revealed that the FG prostheses provoked more SED to the bone. The FG prostheses carried less stress, while more stress was induced to the bone and cement. Meanwhile, less shear interface stress was stimulated to the prosthesis-bone interface in the noncemented FG prostheses. The cement-bone interface carried more stress compared to the prosthesis-cement interface. Stair climbing induced more harmful effects to the implanted femur components compared to the normal walking by causing more stress. Therefore, stress shielding, developed stresses, and interface stresses in the THR components could be adjusted through the controlling stiffness of the FG prosthesis by managing volume fraction gradient exponent.

Design and Analysis of Porous Functionally Graded Femoral Prostheses with Improved Stress Shielding

“…However, utilizing an SP unit cell for femur prostheses is a novel work that does not have any counterpart. In this regard, the present study is comparable with some recent research works [31,39].…”

“…In this study, a finite element investigation is performed to find optimum porous FG prosthesis with SP unit cells. Stress distribution of the uniform prosthesis (UP) for two paths (Figure 7) is compared with Ataollahi et al [31] (see Figure 8). The results show a good agreement between results of the present model and those of Ataollahi et al [31] verifying the FEM accuracy.…”

“…Stress distribution of the uniform prosthesis (UP) for two paths (Figure 7) is compared with Ataollahi et al [31] (see Figure 8). The results show a good agreement between results of the present model and those of Ataollahi et al [31] verifying the FEM accuracy. The FEM model can reduce the cost of fabrication and precisely predict the mechanical properties of the prosthesis.…”

“…According to the previous studies, the mechanical properties of the cortical and trabecular bone are presented in Table 1 [30,31]. The cortical bone is considered a transversely isotropic elastic material, but the cancellous bone is assigned to a linear isotropic elastic material.…”

Corrosion Susceptibility and Functionally Graded Properties of Ti-35Nb-4Sn Alloy Processed by Laser Remelting

“…Results show that the selected laser processing parameters allowed the formation of a structure with functionally graded elastic modulus, ranging from a relatively low value of 75 GPa up to 110 GPa, which is close to the elastic modulus of currently used implant materials 1 . The development of Ti-Nb implants with graded elastic modulus has been investigated by several researchers 14,15,17,18,34,35 . In this context, laser remelting with controlled additions of oxygen or nitrogen stands out as a potential route for manufacturing of components with functionally graded elastic modulus in a fast and simple way.…”