Endoprosthesis for knee joint arthrodesis

摘要

Endoprosthesis (1) for arthrodesis of the knee joint with a. a part of the femur (2) having a femur connection structure (5) for the fixed connection with the distal end of the femur, b. a part of tibia (3) having a tibia connection structure (6) for the fixed connection with the proximal end of the tibia, c. a coupling section of the femur side (7) configured in the femur part (2), d. a coupling section of the tibia side (8) configured in the tibia part (3), in which the coupling section of the femur side (7) and the coupling section of the tibia side (8) are connected between yes pivotally with respect to one another around a pivot axis of prosthesis, which runs essentially horizontally medially to laterally in the stenting position (1) as a knee replacement and therefore in its corresponding position essentially with the position of the pivot axis of the natural knee, e. at least one interlocking element (15, 16) that can be moved from one side to another between an interlocking position, in which the coupling section of the femur side (7) and the coupling section of the tibia side ( 8) rigidly interlocked with each other in a predetermined pivot position, and a release position, in which a pivot of the femur side coupling section (7) and the coupling side side section is possible tibia (8) relative to each other around a pivot axis of prostheses, f. a clamping and resetting means (22), which forces the interlocking element (15, 16) with a clamping force in the interlocking position and maintains it therein, and g. an unlocking mechanism, by means of which the interlocking element (15, 16) can be moved in the opposite direction to the clamping force from the interlocking position to the releasing position, characterized in that one of the coupling sections, section of Femur side coupling (7) or tibia side coupling section (8), has a hollow cylindrical section (9) closed on both front sides, circular in cross section, which is oriented with its longitudinal axis of cylinder at length of the prosthetic pivot shaft, and because the other coupling section, tibia side coupling section (8) or femur side coupling section (7), has a throat-shaped support section (11) hollow, which runs parallel to the pivot axis of prostheses, for rotating reception of the hollow cylindrical section (9) around the longitudinal axis of the cylinder and a stop wall (12), which gave it runs transversely to the pivot axis of the prosthesis and forms a stop for the hollow cylindrical section (9), at least two receiving holes (21) guided parallel to the axis of the groove (12) being provided in different positions prosthesis pivot, the interlocking element (15, 16) comprising a piston plate (15) movably disposed in an interior space (10) of the hollow cylindrical section (9) in the longitudinal direction of the cylinder, in which at least one locking pin (16) is eccentrically arranged, which runs in the longitudinal direction of the cylinder and protrudes from the piston plate (15) in the direction of the stop wall (12), penetrating the pivot of interlocking (16) with its free end an opening (20) on the front side (19) of the hollow cylindrical section (9) directed towards the stop wall (12) and, in a relative pivoting position of the two sections of coupling (7, 8), in which it is aligned with one of the receiving holes (21) in the abutment wall (12), it can enter through the movement of the piston plate (15) in the longitudinal direction of the cylinder and exit this.