Abstract: A knee revision prosthesis that provides decreasing valgus-varus and medial-lateral restraint as the knee rotates from extension to flexion, and then increasing restraint as the knee rotates from flexion to full extension. The prosthesis includes a femoral component and a tibial component. The femoral component includes a guide box fixed to the femoral mounting surfaces intermediate the condyles. The tibial component includes a central post fixed intermediate the tibial concavities, which articulates within the guide box and constrains rotational movement of the femoral and tibial components relative to one another in the coronal plane and transverse planes. The post and guide box are constructed and arranged to provide progressively decreasing and then progressively increasing rotational constraint of the femoral component in the coronal and transverse planes as the femoral component rotates in the sagittal plane between full extension to a position in flexion, and then back to full flexion, respectively.