Ceramic and Polymeric Composite Materials used in Reinforcing UHMWPE for Improved Mechanical and Tribological Properties in Orthopedic Applications

Abstract

UHMWPE is a popular choice of biomaterial for joint replacements, particularly in hip, knee, and shoulder replacement procedures, notably as sliding material in between the load bearing surfaces due to its superior biocompatibility, tensile yield, impact strength, and high crystallinity. Even though it has good mechanical qualities, it has a relatively low wear resistance, which causes wear particles to shred and trigger immunological reactions and possibly osteolysis. This also has an impact on the implant’s lifetime. The wear issue can be solved using a variety of approaches, including thermal therapy and antioxidant infusion. The mechanical qualities suffer as a result of these methods’ efficacy in addressing tribological problems. One such way of reducing wear and oxidation rates while preserving mechanical characteristics is reinforcing the conventional UHMWPE with various composite materials. In this review the tensile and tribological properties of such ceramic and polymeric materials like zirconia, hydroxyapatite, carbon nanotube and graphene are evaluated. This review will investigate several ceramic and polymer-based fillers as an alternative to currently used methods such as improved radiation cross-linking and antioxidant treatment. CNT reinforced UHMWPE is still in the testing stage and is not yet on the market due to biocompatibility concerns. However, when compared to their competitors, their tribological properties are adequate but not exceptional. The best tensile properties are found in hydroxyapatite reinforced UHMWPE (but only at high concentrations such as 30wt%), followed by CNT. They do not have biocompatibility issues like CNT because of their structural similarity to natural bone. They also outperform CNT and ATZ composites in terms of tribological properties. As a result, they are best suited for reinforcement (with UHMWPE).