Strain telemetry in orthopaedics

The accuracy with which the stresses in a complex engineering structure can be determined is limited by the accuracy of the estimation of the forces, geometry and constraints applied to the structure. In the field of biomechanics as applied to the human patient, it is often extremely difficult to determine these variables. In consequence, the direct measurement of internal forces or deflections in an implant system using strain gauges and telemetry is of importance, enabling such devices to be designed with much greater confidence than hitherto. This chapter will present a review of the applications of telemetry in orthopaedics to illustrate the range of applications to which it can be applied, the type of data that can be obtained and an overview of modern telemetry techniques.