Damage-tolerant modular implants

Double modular hip prostheses enable the surgeon to respond to individual patient conditions and achieve the best possible surgical results. Nevertheless these connections lead to a higher probability of failure because they have a greater number of mechanical interfaces compared to monolithic implants. The most common failure mechanism in these interfaces is the occurrence of micromotions. These micromotions can lead to wear and corrosion and thus loosening, which can result in implant failure. In subproject A04, we create a fundamental understanding of the damage mechanisms of modular implants based on their surface and subsurface properties in order to use this to derive novel, damage-tolerant implant modifications based on mechanical engineering principles.

Load-adapted surface and subsurface properties of this double modular connection are combined with a novel design and sensor integration to detect implant failure. The effects of the new process strategy on the surface and subsurface properties and the resulting failure mechanisms are investigated experimentally in a test setup under different loading scenarios and in different test media. The resulting micromotions are detected using eddy current sensors. The manufacturing processes are modelled to gain insights into their influence on the surface and subsurface properties responsible for failure.