Method to Determine the Effect of the Frontal Plane Tibiofemoral Knee Angle on the Varus-Valgus Moment at the Knee During Stance and Gait

Osteoarthritis (OA) is a degenerative disease of articular cartilage that affects millions of people [1]. Local biomechanical factors may severely affect initiation and progression of OA due to changes in loading conditions at the cartilage. The frontal plane tibiofemoral alignment effects the varus/valgus moment which could increase the overall loading at the knee. Biomechanical studies have reported that the varus moment is a key determinant in the load distribution at the knee [2, 3] and has been linked to OA progression [4, 5]. A normal knee will have a tibiofemoral angle approximately 7° valgus [6]. Deviation from this angle leads to a knee joint with a varus or valgus condition. In this investigation, a motion analysis procedure was developed to determine the affect of the frontal plane tibiofemoral angle on the force and moment reactions at the knee. The results of these methods could be utilized in a subject specific finite element model to determine the stress and strain at the knee cartilage and to suggest measures to prevent OA.