The onset and progression of knee osteoarthritis and the cartilage degenerative process are related, among biological and mechanical factors, to the knee contact forces of the medial compartment, where the major percentage of the total contact force is transferred. Musculoskeletal modeling represents a state-of-the-art tool to predict knee contact forces, which are affected by two major geometric parameters: tibiofemoral alignment and contact point locations. Recent research show that medial contact force has a controversial level of correlation with tibiofemoral alignment and a marked correlation with contact points. However, there are limited and controversial data on osteoarthritis subjects, and few studies analyzing activities different from walking and without the inclusion of the geometric parameters.