Abstract: A knee-joint prosthesis including a tibial insert (5) between a tibial plate (1) provided on its outer surface with means for fixing to a tibia, and a femoral part comprising a condyle provided with means for fixing to the femur, the tibia insert (5) being mounted on the tibial plate (1) and comprising at least two upper surfaces (7) complementary in shape with the outer surface of the condyles, a tenon (2, 3, 4) is fixed to the inner surface of the tibial plate (1) and projects upwards and comprises an oblong part (4) extending parallel to the inner surface of the tibial plate (1), and the tibial insert (5) has a cavity (9) in which the oblong part (4) engages with possibility of rotation and translation of the tenon (2) relative to the tibial insert (5).

Abstract: Knee prosthetic, incorporating a prosthetic femoral component designed to be fixed to the furthest or nearest extremity, of the femur, a tibial prosthetic component designed to be fixed to the nearest or upper extremity of the tibia and at least one intermediary mobile meniscoid prosthetic involving a lower surface working together by sliding with the complementary upper surface of the tibial component, and at least one upper concave surface working together by sliding with a lower condyloid convex surface of the femoral component, characterised by the fact that the upper surface of the tibial component and the lower surface of the meniscoid component are flat and sloped in the same angle from the top at the rear towards the front.