The Use of C.P. Titanium in Medical Friction Pairs

An advance in the material engineering of biomaterials intended for hip joint replacement prostheses is a very important social matter due to incurable diseases or injuries of human joints happening to many people. The chapter is devoted to the study of the tribological behaviour of the new “nitrided c.p. titanium/ultrahigh molecular weight polyethylene (UHMWPE)” medical friction pairs in artificial hip-joints. The efficiency of these pairs is mainly related to the fact that c.p. titanium is a biocompatible material with human body tissues. A new lubricant based on chondroitin sulphate was investigated compared to commonly used bovine blood serum. The technology of thermodiffusion nitriding (TDN) of the c.p. titanium femoral head was optimised based on the results of the tribological experiments. It was shown that the use of step-by-step regime of nitriding with subsequent polishing of the nitrided c.p. titanium surface for surface hardening decreases the wear of the UHMWPE component by more than two orders of magnitude and the friction coefficient by 6 times. The comparison of the efficiency of the implant materials indicated that nitrided c.p. titanium exceeds the stainless steel and CoCrMo as far as the friction coefficient and specific wear of the UHMWPE component of the tribo-pair are lower, and it is at the level of ZrO2 zirconium ceramics. According to testing of «nitrided c.p. titanium/UHMWPE» friction pairs on stand-simulator of biomechanical human movement, the wear rate of the UHMWPE cup paired with a titanium head is 1.28 mg/million cycles, compared with 4.26 mg/million cycles for a friction pair with Co-Cr-Mo, i.e. less than 3.3 times. Thus, the developed technology of manufacturing a head of c.p. titanium allows to obtain a hinge joint Ti/UHMWPE, the resource of which exceeds the resource of the pair Co-Cr-Mo/UHMWPE. An advance in the material engineering of biomaterials intended for hip joint replacement prostheses is a very important social matter due to incurable diseases or injuries of human joints happening to many people. A new lubricant based on chondroitin sulphate was investigated compared to commonly used bovine blood serum. Endoprosthetics of the human joints is an effective method of restoring the working capacity of a person in the case of incurable diseases or injuries. The reason for the surgical revision operation can be negative phenomena associated with the insufficient biocompatibility of the applied materials with the tiss