Simulating the bone-titanium interfacial changes around transfemoral osseointegrated implants using physical models and modal analysis

Non-invasive vibration analysis is being considered as a method to monitor the healing progression of femoral implants in transfemoral amputees. Studies to date have successfully detected gross alterations in the physical properties of the interface region of physical bone-implant models using vibration techniques. This paper describes the development of a series of physical models which simulate the incremental bone-implant interfacial changes during progressive osseointegration. The capability of modal analysis to detect the changing interface conditions is investigated. The model resonant frequencies and their mode shapes altered due to the different interface conditions. Higher resonances were shown to be more sensitive to interface changes than the fundamental frequency. The findings demonstrate the potential of modal analysis for this application and the technique warrants further investigation.