Fig. 1

Radiograph showing the measurement of component alignment angles in the coronal plane. The alignment of the femoral components was measured by the intersection of a line drawn across the base of the femoral component and the mechanical axis. The alignment of the tibial components was measured by the intersection of a line drawn across the base of tibial component and the mechanical axis. Radiographic evaluation system originally appeared in J Bone Joint Surg Am. 2009;91:14–19. α frontal femoral angle, β frontal tibial angle