with adjustable damping in the direction of flexion such that a prosthetic unit attached to the knee joint can be adapted for climbing stairs application_number US 76835610 A description fig1 shows a prosthesis wearer 1 with a knee joint prosthesis 2 which is secured by upper attachment elements to a femoral stump the prosthetic leg 20 stands with the healthy contralateral leg 4 in front of a step to reach the next step up a prosthetic foot 6 has to be guided over the step edge an active bending of the hip as is indicated by the arrow 7 assists the passive bending of the knee which is shown by the arrow 8 and which because of the mass inertia both of the prosthetic foot 6 and also of the connection element 3 occurs from the prosthetic knee joint 2 to the prosthetic foot 6 for this purpose a minimum extension damping is required to ensure that after a flexion of the hip the prosthetic foot 6 does not swing forward and is not moved against the riser or under the step 5 in the lift phase as shown in fig2 the prosthetic foot 6 is guided upward as far as possible in a perpendicular manner this possibly being initiated by a slight rearward movement the lift is detected via the flexion angle u03b1 between the connection element 3 and the thigh or via a reduction of the axial force in the connection element 3 without flexion of the prosthetic foot 6 it is also possible to detect the stair climbing mode and thus the lowering of the flexion damping to a value below the.