Tribological behavior of polyethylene for biomedical material

• Main Author: Neo, Li Ping
• Other Authors: Liu Erjia
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/54175
• Institution: Nanyang Technological University

The study of tribology on artificial hip joint bearing surfaces has been carried out for many decades. The analysis of the tribological interactions at the bearing surfaces gave researchers many insights as to which combinations of materials used were suitable for the application. With an expected service life of around 25 years on most devices, and with younger and younger patients undergoing this surgery, it is of great importance to investigate on the tribology on hip joint bearing surfaces. In addition, wear of total hip prosthesis is a significant clinical problem that involves, nowadays, a too high number of patients. In order to acquire further knowledge on the tribological phenomena that involve hip prosthesis wear tests have been conducted on employed materials to extend lifetime of orthopaedic implants. Polyethylene wear debris, and the resulting inflammatory response leading to osteolysis and loosening, is the primary mode of failure limiting the life span of total hip replacements. Alternative bearing surfaces, including ceramic-on-polyethylene, have been investigated in an effort to decrease the amount of polyethylene wear debris. The purpose of this study was to evaluate use of ceramic-on-polyethylene total hip prostheses. In this project, the author looked to identify some of the key trends in specific wear rates and friction coefficient found in earlier reports for ceramics on polyethylene bearing surfaces. Numerous ball -on-disk experiments were then conducted to come up with a suitable set of parameters for study and then proceeded to determining these trends on ceramic on polyethylene bearing surfaces which were carried out in a Hank’s balanced salt solution (HBSS). All the experiments were conducted on the highly polished ultra-high-molecular polyethylene (UHMWPE 1000) sample and high density polyethylene (HDPE 300). The specimen surface morphology was analysed in order to seek a better understanding of fatigue wear and plastic deformation. The studies provided useful information about artificial joints based on ceramic on polyethylene bearing surface interaction. It gave a better idea of the suitability of ceramic versus PE1000 and PE300 that was analysed in form of their friction coefficient and specific wear rate. The surface morphology would also helped in understanding the effects it had on the survival of the artificial hip joints. Thus, the findings from this project proved to be very useful and eligible for future reference in the study of artificial joints.