The invention relates to a knee joint prosthesis for replacing the articulating knee portion of a femur and a tibia. The knee joint prosthesis includes a femoral component, a tibial component, a bearing member, a guide post and a mechanically reconstructed ligament. The femoral component includes a first femoral bearing surface and a second femoral bearing surface. The tibial component includes a tibial bearing surface. The bearing member includes a first bearing surface which is operable to articulate with the first femoral bearing surface, a second bearing surface which is operable to articulate with the second femoral bearing surface and a third bearing surface which is operable to articulate with the tibial bearing surface. The guide post extends from the tibial component. The mechanically reconstructed ligament is coupled to both the tibial component and the femoral component to prevent the knee joints from dislocating and guiding the femoral component along a desired path during extension and flexion.