The invention relates to prosthetic knee joint comprising an upper part (2), which has an upper connecting means (3), and a lower part (4), which is pivotably mounted on the upper part (2) and which has a lower connecting means (5). A vacuum pump (20) with an inlet (6) and an outlet (8), said pump being driven by the relative movement of the upper part (2) to the lower part (4), is associated with the prosthetic knee joint.
