Measurement on the coronal plane (FMA, femoral mechanical axis: a line connecting the centers of the femoral head and knee joint; CTL, condylar tangent line; BTB, border of tibial baseplate; TMA, tibial mechanical axis: a line connecting the centers of the knee joint and ankle joint; MDFA, medical distal femoral angle; MPTA, medical proximal tibial angle; HKA, medical angle between FMA and TMA).