The development of a geometric methodology for the determination of volumetric wear in total joint replacements & development of a total knee replacement joint using new and novel measurement techniques.

Total joint replacement is one of the most common elective surgical procedures performed worldwide, with an estimate of 1.5 million operations performed annually.
It has long been recognised that wear analysis of total joint replacements is an important means in determining failure mechanisms, functionality and improving longevity of these devices. The standardised method for assessing wear volumes in such joints is through gravimetric means and it has been shown that this method is a useful tool for indicating simulated wear volumes. This method is, however, of little value when considering the case of a clinically explanted bearing surface for which, by definition, there is no ‘pre-wear’ data.
The purpose of this thesis is to present a co-ordinate measuring machine (CMM) based technique for assessing the volumetric material loss in total joint replacement joints and to establish its effectiveness. To this end uncertainty calculations are completed for the specific case of orthopaedic component measurement.
In this thesis methods have been developed in this thesis for measurement of in vitro wear of total knee replacement bearings and a number of knee joint simulator tests have been completed and their results discussed.
An initial test investigating the possible use of metal-on-metal bearings for total knee replacement is described. A test profile for simulation of deep squat is developed, a simulator test completed and the results discussed.
An adapted version of the developed CMM measurement method is further adapted and developed for measurement of clinical wear from retrieved bearings and the implications of this capability are examined and discussed.
In tandem with this methods are developed for the mapping of wear location and component form deviation and the implications that this has for manufacturing control and wear potential is discussed at length. Overall future developments and work are explored.