An optimised electronic system for in-vivo stability evaluation of prostheses in total hip and knee arthroplasty

This paper describes the optimization of a set of initial parameter values in an implantable, remotely interrogated electronic displacement sensor for use in applications of such as implants for total hip and total knee arthroplasty. This is the first reported implantable electronic system capable of satisfactorily measuring both postoperative migration and micromotion. In earlier reported work by the same authors, the initial parameter values of the differential variable reluctance transducer (DVRT), which is the key component of the system, were chosen somewhat randomly and were not optimal. In this short paper, the influence of the initial resistance and coil parameters in the bridge on the operation of the DVRT is explored in terms of the accuracy, resolution, detection range of the measurement and the coil size.