Predictions of Condylar Contact During Normal and Medial Thrust Gait

The medial compartment of the knee is the joint most often affected in those with osteoarthritis (OA). The knee adduction moment is a widely used surrogate measure of joint loading as direct measures are not possible except for a few individuals fitted with a force sensing prosthesis. A reduction in the frontal plane moment is believed to be associated with reduced joint compression. As such, treatments and/or gait alterations to reduce the magnitude of the adduction moment have been sought for those with knee OA. Walking with a medial thrust gait has been shown to reduce the magnitude of the knee adduction moment. The purpose of this paper is to apply our EMG-driven musculoskeletal model of the knee to predict muscle forces and condylar loading during normal and medial thrust gait for an individual fitted with an instrumented knee. It was anticipated that walking with a medial thrust gait would produce a reduced knee adduction moment. We propose however that a reduced knee adduction moment may not necessarily be associated with a decrease in medial compartment loading, and importantly, one must consider how the knee extensor moment changes before making inferences about joint loading.