ERROR ANALYSIS FOR A KNEE MOTION GONIOMETER.

There is growing interest in using six-degree-of-freedom electrogoniometers to measure knee motion, both in laboratory in vitro testing and in patient testing. The source and magnitude of several error sources in the use of six-degree-of-freedom goniometers (instrumented spatial linkage equals ISL) are discussed in this paper. The system of interest is an ISL attached to the human leg about the knee. The ISL is intended to measure relative motion between tibia and femur articulating surfaces. This can potentially be done in several ways, but for purposes of estimating errors, the method here will be to predict relative motion between two points in initial contact at the joint surfaces.