The role of tribology and metrology in the latest development of bio-materials

Total joint replacement is one of the most common elective surgical procedures performed worldwide, with an estimate of 1.5 million operations performed annually. Currently joint replacements are expected to function for 10-15 years, however, with an increase in life expectancy, and a greater call for all types of joint replacement due to increased activity levels, there is a requirement to improve their function to offer longer term improved quality of life for patients. Typically it is the hip and knee joints which encompass the great majority of these elective surgical procedures; however replacement of ankles shoulders, elbows, finger joints and other bearing surfaces are not uncommon. Most replacement joints fail as a complication of the basic wear and debris generation process. The quest for longer life from replacement joints has consequently concentrated on developing materials and designs which minimise the generation of wear particles. This paper summarises some of the recent developments in the field orthopaedic joint replacement, in particular the paper concentrates on the wear of new material combinations and methodologies of wear simulation and wear assessment using precision metrology.