B1.3 - Excitation and Wireless Lock-In Measurement of Hip Prosthesis Vibrations for Loosening Detection

An experimental setup for excitation and detection of hip prosthesis loosing is developed and analyzed. Small vibration signals are detected by acceleration sensors fixed in the prosthesis. Lock-in technique is applied to separate sensor signals at low signal-to-noise ratio. Stand-alone measurements were taken at an artificial thigh where an electrodynamic audio shaker was fixed at the knee using an appropriate designed support structure. It could be demonstrated that the measurement setup is suitable to excite and to measure oscillations of a prosthesis which was partially fixed in an artificial femur.