Biomaterials and Coatings for Artificial Hip Joints

Abstract

Biomaterials have made great progress in the medical device industry. Every year large numbers of artificial organs are implanted into the body, for example, heart valves, cardiovascular stents, and hip joints. The implanted materials which corrode in the body environment and result in toxic reactions, can be divided into four categories: metals, polymers, ceramic, and composites. However, for artificial hip joints, they not only need to resist friction and corrosion but also protect against a large amount of wear debris or particles generated, which result in the loosening of the prosthesis. Metals and polymers, as traditional artificial joints materials, are widely employed in prosthetic hip replacements and most of them are successful clinically. The poor fracture toughness of ceramics limits their use in load-bearing applications. It is of great interest for composite materials and their combined properties, for example, mechanical and bio-tribological properties, to be suitable for artificial joints. To improve the implant’s life expectancy, surface modification of friction pairs of artificial joints is crucial in the biomedical field. The implant’s surface is coated with carbon-based and other nanomaterials or is modified by different methods. Diamond-like carbon (DLC) coatings have received much attention in load-bearing joints due to their excellent mechanical, tribological, and biological properties. This chapter introduces the different implant materials and coatings used in artificial joints, especially in hip joint replacements. The research progress of biomaterials and DLC coatings in the surface modification of friction pairs of artificial joints is reviewed, including the biotribological properties and biocompatibility of different kinds of artificial hip joints.