The subject of the offer is a mechatronic system for very accurate imitation of the movement of the knee joint – movement between the tibia and femur, including rolling and sliding. The mechanism, owing to the use of a mechatronic system consisting of three drives, can imitate previously measured and recorded data about the movement of the patient knee joint and allows to adjust the trajectory for their individual needs. In addition, the movement of the other knee joint can be treated as a reference and can be measured by the same mechanism. The invention is covered by patent protection.