Study on Dynamic Contact Pressure Distribution at Tibio-Femoral Joint : 1st Report, Measuring System and Experiment

Abstract

Presence of abnormal loads in the meniscus, ligament and articular cartilage of the knee joint has been suspected as one of the probable causes of osteoarthritis. Hence, the knowledge of the contact stress distribution at this joint in normal as well as abnormal states is necessary. In this study, an improved method of measuring dynamic contact stress using a set of microcapacitance pressure sensors is illustrated by means of in vitro experiments conducted on a knee joint of a cow's hind leg with intact ligaments, which was allowed to undergo simulated motion under preestimated normal loads. Several methods of deriving a mathematical function approximating the pressure distribution at the tibio-femoral joint are also illustrated on the basis of a set of experimentally observed pressure data taken at discrete points. The availability of such a mathematical function is likely to open a new avenue in biomechanical as well as etiological investigations of the knee joint.