A knee joint endoprosthesis has an element for the femur (2) which is substantially U-shaped when seen from a medial to a lateral angle, one horizontal, two diagonal and two vertical support surfaces facing the femur for accommodation on the resected femur bone, which is fitted with two runners (24, 25), and an element for the tibia (1) having two slide tracks (4, 5) on which the runners for the femur element can roll, and optionally slide, and a horizontal support surface (6) facing the tibia for accommodation on the resected tibia. The femur element (20) and tibia element (1) are configured without any shanks. At least both diagonal support surfaces of the femur element (2) and the horizontal support surface (6) of the tibia element (20) are fitted with an open-mesh, three-dimensional spatial network structure (7) which is an integral component of the base structures (8, 8′) of the femur element (20) and the tibia element (1). Two latches (21, 22) angled toward the femur and provided with at least one respective through hole (23) are medially and laterally formed on the femur element (20), whereby a bone screw (26) can be inserted therein; and two latches (11,12) angled toward the tibia and provided with at least one respective through hole (18) are formed on the tibia element, whereby a bone screw (14) can be inserted therein.