A metrology solution for the orthopaedic industry

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 knee replacement due to increased activity levels, there is a requirement to improve their fimction to offer longer term improved quality of life for patients. The amount of wear that a joint incurs is seen as a good indicator of performance, with higher wear rates typically leading to reduced fimction and premature failure. New technologies and materials are pushing traditional wear assessment methods to their limits, and novel metrology solutions are required to assess wear of joints following in vivo and in vitro use. This paper presents one such measurement technique; a scanning co-ordinate metrology machine for geometrical assessment. A case study is presented to show the application of this technology to a real orthopaedic measurement problem: the wear of components in total knee replacement. This technique shows good results and provides a basis for further developing, techniques for geometrical wear assessment of total joint replacements.