Development of a Standard for Structural Testing of Implants in Transfemoral Osseointegrated Prostheses

Abstract: The aim of this Master's Thesis was to develop a standard for structural testing of implants to be used in transfemoral osseointegrated prostheses, since there is a lack of such standards for this type of implant. The methods used in this project include a literature study, a review of ISO standards, simulations of gait in a software called OpenSim, and a comparison of the OpenSim results with measurements from a load cell. Equivalent stresses in the implants were also calculated for both the OpenSim and load cell data, to establish the test values for the standard and to evaluate the worst case scenario. From the results it was concluded that the implants should be tested for compression, bending and torsion, in a cyclic test that simulates gait. A static test corresponding to more severe loading situations, such as stumbling or falling, should also be considered. The results from OpenSim were consistent with the load cell data to some extent, despite that the simulations were based on normal gait while the measurements were taken from amputees using osseointegrated prostheses. Because of this, the OpenSim results were not found suitable to use in the developed standard, and the test values for the cyclic test were therefore based on the load cell data. Further development opportunities of the outcome of this project include improving the OpenSim models, completing the standard, performing more extensive load cell studies, and testing the developed standard practically.