An ankle replacement prosthesis (100; 800), comprising: a tibial component (120; 720) having a tibial bearing component providing a convex bearing surface and a tibial attachment component configured to be attached to the patient's tibia ; and a talar component configured to be attached to the patient's talus and providing a concave bearing surface configured to interface with the convex bearing surface of the tibial bearing component to provide a joint of the ankle replacement prosthesis, characterized in that the tibial bearing component and the tibial attachment component are configured to be secured to one another by a pivotal attachment that allows pivoting or rotation between the tibial bearing component and the tibial attachment component relative to each other after implanting of the ankle replacement prosthesis to emulate natural lateral motion of an ankle, wherein the pivotal attachment comprises: a post on the tibial attachment component; an aperture in the tibial bearing component configured to receive the post; and a lip formed in the aperture and configured to allow pivoting or rotation between the tibial bearing component and the tibial attachment component about an axis of loading parallel to a direction the post is fitted into the aperture; and wherein the post has one or more tabs ; wherein the aperture has one or more tab receiving areas corresponding to the one or more tabs on the post; and wherein the lip engages the tabs of the post to maintain the post within the aperture and to allow the tibial bearing component to rotate with respect to the tibial attachment component about an axis of loading . a tibial component (120; 720) having a tibial bearing component providing a convex bearing surface and a tibial attachment component configured to be attached to the patient's tibia ; and a talar component configured to be attached to the patient's talus and providing a concave bearing surface configured to interface with the convex bearing surface of the tibial bearing component to provide a joint of the ankle replacement prosthesis, characterized in that the tibial bearing component and the tibial attachment component are configured to be secured to one another by a pivotal attachment that allows pivoting or rotation between the tibial bearing component and the tibial attachment component relative to each other after implanting of the ankle replacement prosthesis to emulate natural lateral motion of an ankle, wherein the pivotal attachment comprises: a post on the tibial attachment component; an aperture in the tibial bearing component configured to receive the post; and a lip formed in the aperture and configured to allow pivoting or rotation between the tibial bearing component and the tibial attachment component about an axis of loading parallel to a direction the post is fitted into the aperture; and wherein the post has one or more tabs ; wherein the aperture has one or more tab receiving areas corresponding to the one or more tabs on the post; and wherein the lip engages the tabs of the post to maintain the post within the aperture and to allow the tibial bearing component to rotate with respect to the tibial attachment component about an axis of loading . a post on the tibial attachment component; an aperture in the tibial bearing component configured to receive the post; and a lip formed in the aperture and configured to allow pivoting or rotation between the tibial bearing component and the tibial attachment component about an axis of loading parallel to a direction the post is fitted into the aperture; and wherein the post has one or more tabs ; wherein the aperture has one or more tab receiving areas corresponding to the one or more tabs on the post; and wherein the lip engages the tabs of the post to maintain the post within the aperture and to allow the tibial bearing component to rotate with respect to the tibial attachment component about an axis of loading . <EOS>