Stiffness and strength tailoring of a hip prosthesis made of advanced composite materials

Abstract

This work is concerned with the design of hip prostheses using advanced fiber reinforced composite materials. The major focus of the study is to evaluate how the stiffness and strength of composite hip prostheses can be affected by variations in ply orientation and stacking sequence for a selected manufacturing method. This investigation involved both analytical and experimental work. An analytical model was developed which consists of a stress analysis and a failure analysis. A finite element program was developed during the course of the investigation for analyzing stresses, strains, and deformations of composite stems with a simplified configuration. Failure and mode of failure were predicted by appropriately selected failure criteria. Experiments were also performed on T300/976 graphite/epoxy composites to verify the analysis and the computer calculations. Both testing and analysis accounted for the various combinations of in-plane and out-of-plane (torsion) loading that can act on the prosthetic hip. Simplified composite stems with a 120 layer thickness were fabricated and tested. An excellent agreement was found between the measured strain data and the numerical calculations. Using the program, parametric studies were performed. It was found that an optimal design of hip stems can be achieved by using advanced fiber-reinforced composite materials, but great care must be taken when selecting the appropriate ply orientation and stacking sequence for a chosen fabrication method.

Fabrication of Ti/polymer biocomposites for load-bearing implant applications

“…This phenomenon, termed "stress-shielding induced bone resorption", is one of the main factors necessitating revision surgery. To address the concerns related to the stress-shielding effect, considerable amount of research has been devoted to the development of new implant materials with bone-matching modulus, such as polymer based composites (Bonfield et al, 1981;Chang et al, 1990;Wang et Stamboulis et al, 2002;Wang, 2003), carbon-carbon composites (Christel et al, 1987) and metastable ␤-titanium alloys (Long and Rack, 1998;Qazi et al, 2004), for the fabrication of permanent implants. Although the polymer-based composites can be designed to have a similar elastic modulus to that of natural bones, their fatigue resistance and fracture toughness are inferior to that of the natural bones.…”

Adherence Properties of Acrylic Bone Cement to Alumina Ceramics Designed for Clinical Applications

“…Materials with a high exibility tend to have less bone resorption and the stress level in bone is significantly lower. The mechanical environment of the host bone is altered by the implantation of a foreign material and consequently, bone remodeling occurs in order to adapt the bone structure to this new situation [7]. The aim of this study is to investigate the adherence properties of acrylic cement (based on PMMA) to alumina ceramics, suitable for orthopedic and dental applications, as bio-inert components in prosthetic surgery.…”

Performance of CF/PA12 composite femoral stems

“…The corrosion resistance, mechanical reliability and tailorability of thermoplastic polymer-based composites make them a potential substitute for metallic materials, with a wider range of bone-matching properties. In fact employing advanced composite materials has become a common trend in the development of novel hip stems [4][5][6][7][8][9][10][11].…”

“…Previous studies on polymer composite materials designed for hip prostheses include the work from Reinhardt et al [4], Simoes and Marques [5][6][7] as well as many other investigators [8][9][10][11]. Reinhardt et al designed a thermosetting polymer-based composite hip prosthesis made by resin transfer molding (RTM).…”