Chapter 7 - Ceramic Coatings in Load-Bearing Articulating Joint Implants

Abstract

The number of knee replacement surgeries is expected to reach 3.48 million annually by 2030 and revision surgeries due to aseptic loosening, release of potentially toxic metallic ions, inflammatory wear debris, and surgical site infection continue to be a cause of significant clinical concern. With increasing numbers of articulating-joint devices being implanted in both orthopedic medicine and dentistry, more and more emphasis is being placed on developing ceramic coating technology that can reduce the friction and wear in mating joint components, in hopes of significantly increasing device life-span and improving the quality of life of patients. In this review, we consider ultrasmooth nanodiamond (NSD)-based hard ceramic coatings as alternative bearing surfaces for metallic components. Such coatings have great potential for use in articulating joints due to their extreme hardness, wear resistance, low friction, and biocompatibility characteristics. These ultrahard ceramic coatings can be deposited by several different techniques resulting in a wide variety of structures and properties. The NSD coatings deposited using chemical vapor deposition are considered to be comprised of nano-size diamond grains embedded in an amorphous carbon matrix. This chapter focuses on recent studies on diamond ceramic surfaces, particularly, for the articulating joints based on an industry standard knee simulator results and macrophage cell response to the nanodiamond wear-debris that could potentially be generated. The chapter concludes with a summary and future perspective on the combination of additive manufacturing method, known as direct metal laser sintering and NSD coating for enhanced wear resistance of articulating surface combined with osteo-integration/infection-resistant coating on nonload-bearing surfaces to produce the next-generation bio-durable joint implants for orthopedic and dental medicine.