A non-invasive method for determining the articular point of a knee joint is disclosed. The method uses a surgical navigation system having stereoscopic cameras which track the positions of infrared emitting or reflecting markers attached to leg portions on either side of the knee joint. A movable marker is used to palpate known landmarks on the leg portions to determine their positions. The leg portions are moved to determine the trajectories of the landmarks relative to the joint. Positional information from the cameras is fed to a data processing system with resident software which uses the positional information and trajectories to mathematically determine the positions of the knee joint articular point according to the laws of kinematics.