HAp Coated Hip Prosthesis Contact Pressure Prediction Using FEM Analysis

Abstract

Total hip replacement is surgical procedure which is widely performed in most of the developed countries due to rapid aging. The extensive application of titanium alloy as hip prosthesis can be seen because of its suitable properties such as good biocompatibility, light weight and high strength. However, coating or bond is required as titanium alloy ineffective to be adhered directly with human bone. Hydroxyapatite (HAp) is common coating material used to bond Ti-6Al-4V hip prosthesis with human bone. HAp-Ti-6Al-4V interface is a possible fretting wear region which is subjected to significant contact pressure. HAp-Ti-6Al-4V interface fretting fatigue delamination leads to contact pressure which can accelerate fretting wear behaviour of HAp coating. Present paper discusses the influence of delamination length and fatigue stress ratio on contact pressure distribution at interface of HAp-Ti-6Al-4V using finite element methodology. A simple two-dimensional finite element contact configuration consisting Ti-6Al-4V substrate, HAp coating and contact pad (representing bone) is employed to examine under static analysis. The finite element predicted results highlighted that contact pressure can be promoted under increased delamination length condition and stress ratio of 0.1 (tension-tension). Contact pressure can accelerate HAp coating fretting wear behaviour.