The asymmetry of the rolling sliding motion of the medial and lateral femoral condyles results in a greater posterior roll of the condyle on the lateral tibial plateau trhan on the medial side. The posterior roll averages 6mm on the medial side compared with 12mm on the lateral side . This difference results in 20 degrees of automatic rotation. Posterior slope of the tibial plateaus and the decreasing radii of curvature of the condyles, the femoral and tibial points of attachment of the medial and lateral collateral ligaents are moving closer to one another. Since the decrease in the radius of cuvature is greater for the lateral tibial plateau slopes more sharply posteriorly than the medial plateau, the lateral collateral ligament becomes more lax than the medial collateral ligament, This has important consequences in terms of elective or active rotation of the tibia relative to the femur.
Paper includes torque rotation curves for the knee during flexion.
Also design characteristics of the replacement. The eccentric redistribution of normal stress is induced by abnormal axial alignment. A vicious cycly may occur with continuing cartilage and subchondral bone degeneration associated with progressively abnormal axial alignment. Osteotomy is one of the surgical methods that can correct joint pathomechanics and may break down this vicious cycle. The tibial mechanical angle measured 1.2x varus.