School of Engineering and Materials Science
Research Student Awards
PhD Thesis: Holographic interferometric analysis of femoral prosthesis
Author: BLATCHER, Steve
Supervisor(s): Julia Shelton
Clinical trails have shown that the design of femoral component can affect the lifetime of a total hip replacement. Therefore it is desirable to develop an in vitro test that can detect prosthesis designs which will lead to shortened lifetimes before they are implanted into patients.
Holographic interferometry is a full-field, non-contact, displacement sensitive technique that is ideally suited to analysing the deformation characteristics of complex structures such as the femur. The technique of holographic interferometry has full-field properties which enable out-of-plane surface deformations to be quantified as a continuous function along the length of the femur, while the non-contact properties eliminate the reinforcement effects inherent to contact methods of deformation measurement. A novel method of quantifying longitudinal surface strains from holographic interferograms of loaded model femurs has been fully examined and the results have been verified using electric resistance strain gauges.
Deformations of intact and implanted model femurs have been compared using quantitative holographic interferometry, and for the first time the technique has been used to measure the longitudinal surface strains of intact and implanted cadaveric femurs. Results have indicated that the deformation characteristics of cadaveric femurs are different to those generated by model femurs and that compensation must be made for interspecimen variation in cadaveric femurs. It has also been demonstrated that different designs of femoral prosthesis cause measurable changes in the deformation on the femoral surface.
The applicability of quantitative holographic interferometry to femoral deformation analysis has been fully demonstrated, and results indicate that it may be possible to make long-term predictions of prosthesis performance from short-term experimental tests.