Bone mass decreases as part of the normal aging process. Varying degrees of settlement of bone mass exist in the load-bearing joints, such as the knees, hips, ankles, and spine. In the proximal tibia, the lateral support of the fibula to the lateral tibial plateau routinely leads to nonuniform settlement, which is more severe in the medial plateau than in the lateral plateau. The slope of the tibial plateau arising from nonuniform settlement results in a transverse shearing force, with the femoral condyle shifting medially during walking and sports. Furthermore, side-slip aggravates the nonuniform settlement of the tibial plateau, especially in the medial plateau. Accordingly, a cycle of increasing the load distribution in the medial compartment and nonuniform settlement occurs. This results in the load from the normal distribution shifting farther medially to the medial plateau and consequently leads to knee varus, aggravating the progression of medial compartment knee osteoarthritis.