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A medical wireless measurement system for hip prosthesis loosening detection based on vibration analysis

: Sauer, S.

Sensors & Transducers Journal 18 (2013), Special Issue, S.134-144
ISSN: 2306-8515
ISSN: 1726-5479
International Conference on Sensor Device Technologies and Applications (SENSORDEVICES) <3, 2012, Rome>
International Conference on Sensor Technologies and Applications (SENSORCOMM) <6, 2012, Rome>
Zeitschriftenaufsatz, Konferenzbeitrag
Fraunhofer IPMS ()

Vibration analysis is a promising approach in order to detect early hip prosthesis loosening, with the potential to extend the range of diagnostic tools currently available in clinical routine. Ongoing research efforts and developments in the area of multi-functional implants, which integrate sensors, wireless power supply, communication and signal processing, provide means to obtain valuable in vivo information otherwise not available. In the current work a medical wireless measurement system is presented, which is integrated in the femoral head of a hip prosthesis. The passive miniaturized system includes a 3-axis acceleration sensor and signal pre-processing based on a lock-in amplifier circuit. Bidirectional data communication and power supply is reached through inductive coupling with an operating frequency of 125 kHz in accordance with the ISO 18000-2 protocol standard. The system allows the acquisition of the acceleration frequency response of the femur-prosthesis system between 500 to 2500 Hz. Applied laboratory measurements with system prototypes on artificial bones and integrated prostheses demonstrate the feasibility of the measurement system approach, clearly showing differences in the vibration behavior due to an implant loosening. In addition a possibility to evaluate the non-linear mechanic system behavior is presented.