FASTENING DEVICE FOR FASTENING A PROSTHESIS SHAFT TO A PROSTHETIC KNEE JOINT, AND PROSTHETIC KNEE JOINT

Abstract

A fastening device for fastening a prosthesis shaft to a prosthetic knee joint that has a proximal top part and a distal bottom part, which are mounted on one another to pivot about a prosthetic knee joint axis. The fastening device has a distal bracket for attachment to the bottom part or to a lower-leg tube. At least one strut extends in the proximal direction from the holder beyond the prosthetic knee joint axis and on the strut a receptacle is arranged proximally to the prosthetic knee joint axis for pivotally mounting the prosthesis shaft about a shaft pivot access. At least one force transfer element is fastened offset to the to the shaft pivot access at a proximal bearing point to transfer a pivoting movement of the prosthesis shaft. The force transfer element is coupled to the top part at a distal bearing point in such a way that a pivoting movement of the prosthesis shaft about the shaft pivot axis causes a pivoting movement of the top part about the prosthetic knee joint axis.

Claims

1. A fastening device for fastening a prosthesis socket to a prosthetic knee joint that has a proximal top part and a distal bottom part, which are mounted on each other pivotably about a prosthetic knee joint axis, the fastening device comprising: a distal holder for securing to the bottom part or to a lower-leg tube; at least one strut extending in a proximal direction from the holder beyond the prosthetic knee joint axis; a receptacle arranged on the strut, proximally with respect to the prosthetic knee joint axis, for the pivotable mounting of the prosthesis socket about a socket pivot axis; at least one force transmission element, offset with respect to the socket pivot axis and fastened at a proximal bearing point in order to transmit a pivoting movement of the prosthesis socket, the force transmission element being coupled to the top part, at a distal bearing point, in such a way that a pivoting movement of the prosthesis socket about the socket pivot axis causes a pivoting movement of the top part about the prosthetic knee joint axis.

2. The fastening device according to claim 1, wherein the proximal bearing point is arranged on the prosthesis socket, or on a lever which is pivotable about the socket pivot axis and coupled to the prosthesis socket.

3. The fastening device according to claim 1, further comprising a bracket, with a receiving device for securing the prosthesis socket to the bracket, mounted on the at least one strut.

4. The fastening device according to claim 3, wherein the receiving device is designed as part of a pyramid adapter.

5. The fastening device according to claim 3, wherein the bracket is designed as a one-arm or two-arm bracket.

6. The fastening device according to claim 1, wherein the distal bearing point is arranged on a carrier which has a coupling device for securing to the top part.

7. The fastening device according to claim 6, wherein the coupling device is designed as part of a pyramid adapter.

8. The fastening device according to claim 1, wherein the force transmission element is designed as a bracket with two branches, which are arranged medially and laterally with respect to the prosthesis socket, form two proximal bearing points, and are connected to each other distally via a crosspiece.

9. The fastening device according to claim 1, wherein the force transmission element is mounted pivotably about the proximal bearing point.

10. The fastening device according to claim 1, wherein the prosthesis socket has at least one of a dimensionally stable end cap on which the at least one proximal bearing point is formed or a distal fastening element is arranged for coupling to the strut.

11. The fastening device according to claim 1, wherein the holder can be secured releasably to the bottom part or to a lower-leg tube.

12. The fastening device according to claim 1, wherein the prosthesis socket has a distal end which protrudes distally beyond the socket pivot axis.

13. The fastening device according to claim 12, wherein the socket pivot axis is configured to be arranged in a region of a natural knee joint axis.

14. A prosthetic knee joint having the fastening device according to claim 1.

15. A fastening device to fasten a prosthesis socket to a prosthetic knee joint, the prosthetic knee joint having a proximal top part pivotally mounted to a distal bottom part about a prosthetic knee joint axis, the fastening device comprising: a distal holder to secure fastening device to the bottom part or to a lower-leg tube; at least one strut extending in a proximal direction from the holder beyond the prosthetic knee joint axis; a receptacle arranged on the strut proximally with respect to the prosthetic knee joint axis, the receptacle configured to pivotably mounting the prosthesis socket about a socket pivot axis; at least one force transmission element offset with respect to the socket pivot axis, fastened at a proximal bearing point, and configured to be coupled to the top part at a distal bearing point in such a way that a pivoting movement of the prosthesis socket about the socket pivot axis causes a pivoting movement of the top part about the prosthetic knee joint axis.

16. The fastening device according to claim 15, wherein the proximal bearing point is configured to be arranged on the prosthesis socket or on a lever which is pivotable about the socket pivot axis and coupled to the prosthesis socket.

17. The fastening device according to claim 15, further comprising a bracket mounted on the at least one strut and having a receiving device to secure the prosthesis socket to the bracket.

18. The fastening device according to claim 17, wherein the receiving device is part of a pyramid adapter.

19. The fastening device according to claim 17, wherein the bracket is a one-arm or two-arm bracket.

20. The fastening device according to claim 15, wherein the distal bearing point is configured to be arranged on a carrier, the carrier having a coupling device configured to be secured to the top part.

Description

[0021] An illustrative embodiment of the invention is explained in more detail below with reference to the accompanying figures, in which:

[0022] FIG. 1 shows a schematic front view of a prosthetic knee joint with a fastening device;

[0023] FIG. 2 shows a side view;

[0024] FIG. 3 shows a side view of a variant, in an extended position;

[0025] FIG. 4 shows the variant according to FIG. 3 in a flexed position, and

[0026] FIG. 5 shows a rear view of the variant according to FIG. 3.

[0027] FIG. 1 shows a schematic front view of a prosthetic knee joint 20 having a top part 21 and a bottom part 22, which are connected to each other pivotably about a pivot axis 23. Damper devices, actuators, end stops and control devices and drives for adjusting resistances, stops or the like can be arranged between the top part 21 and the bottom part 22. A lower-leg tube 30, which connects the prosthetic knee joint 20 to a prosthetic foot (not shown), is arranged distally on the bottom part 22. Customary connecting means, for example a pyramid adapter, for securing to a prosthesis socket can be arranged on the top part 21.

[0028] On the prosthetic knee joint 20, a fastening device 1 is arranged which, in the distal region, has a holder 2 for securing the fastening device 1 to the bottom part 22 or, as in the illustrative embodiment shown, to the lower-leg tube 30. By way of the holder 2, the fastening device 1 is coupled rigidly to the bottom part 22 or the lower-leg tube 30, for example via form-fit elements or via clamping devices.

[0029] The fastening device 1 has two struts 3 or branches 3 which extend from the distal holder 2 in a proximal direction and are arranged medially and laterally with respect to the prosthetic knee joint 20. The two struts 3 or branches 3 are connected to each other, resulting in a U-shaped configuration in the proximal region of the fastening device 1. At the proximal ends of the struts 3 or branches 3, receptacles 4 are formed, for example bearing pins, bearing bores or similar, through which a socket pivot axis 14 runs. Instead of two struts 3 or branches 3, it is possible, in a variant of the invention, to provide only one strut 3 or branch 3, either medially or laterally with respect to the prosthetic knee joint 20. A design with two struts 3 or branches 3 increases the stability and the guiding precision.

[0030] A bracket 7 is mounted pivotably about the socket pivot axis 14, which bracket 7 is likewise U-shaped and has its lowest point, i.e. its maximum distal point, at the center between the two struts 3 or branches 3. A receiving device 17, for example a pyramid adapter, is arranged on the bracket 7 and serves to secure a prosthesis socket 10. On the prosthesis socket 10, designed as a dimensionally stable prosthesis socket for receiving a thigh stump or designed with a dimensionally stable end cap 11, in particular for receiving a thigh stump after a knee disarticulation, a distal fastening element 12 is provided, for example a pyramid adapter receptacle, in order to be able to fasten the prosthesis socket 10 to the receiving device 17 reversibly, with form-fit engagement and with the possibility of alignment. By way of the distal fastening element 12 and the receiving device 17, the prosthesis socket 10 is fixed to the bracket 7 for conjoint rotation therewith and to transmit moment. By being secured to the bracket 7, the prosthesis socket 10 can be pivoted about the socket pivot axis 14. The socket pivot axis 14 runs proximally with respect to the distal end of the prosthesis socket 10. Simple exchange of the components is possible by virtue of the reversible securing via the distal fastening element 12 on the receiving device 17.

[0031] On the bracket 7 itself, a jib or lever 6 is fastened which is coupled rigidly to the bracket 7. The lever 6 extends rearwardly, i.e. in a posterior direction, and forms a proximal bearing point 15. Two levers 6 are formed on or fastened to the bracket 7 and are arranged symmetrically with respect to the longitudinal extent of the prosthetic knee joint 20. A force transmission element 5 extends in a distal direction from the proximal bearing point 15 on the lever 6, where the respective force transmission element 5 is mounted on a carrier 26 at a distal bearing point 25. The force transmission element 5 is mounted pivotably both at the proximal bearing point 15 and at the distal bearing point 20. The carrier 26 connects the two force transmission elements 5 to each other, such that a further U-shaped bracket is formed. The carrier 26 has a coupling device 28 which corresponds to the upper connecting means of the top part 21, for example a pyramid adapter receptacle, similar to the receiving device on the prosthesis socket 10. When the prosthesis socket 10 pivots about the socket pivot axis 14, and the prosthesis socket 10 and thus the stump perform a flexion relative to the lower-leg tube 30 or the bottom part 22, the bracket 7 and thus the two levers 6 pivot, such that the force transmission devices 5 are moved in a distal direction. On account of the distal movement of the force transmission devices 5, the distal bearing points 25 are subjected to a pressing force. On account of the eccentric arrangement of the bearing points 25 relative to the knee joint pivot axis 23, a moment arises about the prosthetic knee joint axis 23, such that the top part 21 is pivoted relative to the bottom part 22 about the prosthetic knee joint axis 23.

[0032] For the prosthesis user, the socket pivot axis 14 thus forms the axis about which the whole prosthetic device pivots, apart from the prosthesis socket 10. By the positioning of the socket pivot axis 14 in the region of the distal end of the prosthesis socket 10, but proximally with respect to the distal end of the prosthesis socket 10, it is possible to position the pivot axis relevant to the user closer to the natural knee joint axis. In this way, it is possible to make available almost identical segment lengths of thigh and lower leg, or of thigh stump and distal prosthesis component. No further change of design of customary prosthetic knee joints 20 is necessary; the connection devices and also the coordination and programming can be kept unchanged. Different leg lengths can be compensated simply by shifting the position of the socket pivot axis 14. Likewise, transmission ratios can be changed by setting and modifying the position of the respective bearing points 15, 25 and the fastening of the prosthesis socket 10 to the struts 3 or branches 3 or the strut 3 or the branch 3.

[0033] FIG. 2 shows a side view of the fastening device 1 with the socket pivot axis 24 at the proximal end of the struts 3 or branches 3, the lower-leg tube 30, and the bottom part 22 of the prosthetic knee joint. The prosthesis socket 10 extends in a distal direction beyond the socket pivot axis 14. On the prosthesis socket 10, a dimensionally stable end cap 11 is arranged or formed, via which the prosthesis socket 10 can be secured to the struts 3 or branches 3. The securing can be effected via proximal bearing points 15, such that the end cap 11 can be secured pivotably on the struts 3 or branches 3 either directly or via intermediate pieces.

[0034] FIG. 3 shows a schematic sectional view of a variant of the invention, in an extended position. By way of a holder 2 which can be arranged exchangeably on the fastening device 1, said fastening device 1, which is designed as an adapter for securing the prosthesis socket to a conventional prosthetic knee joint 20, is releasably connected with its distal end to the bottom part 22 of the prosthetic knee joint 20 or, in a variant, to the lower-leg tube 30. The struts 3 or branches 3 extend in the proximal direction beyond the distal end of the prosthesis socket 10. The socket pivot axis 14 lies proximally with respect to the distal socket end of the prosthesis socket 10, and the branches of the bracket 7 extend distally with respect to the receiving device 17 (not shown), which serves to receive the prosthesis socket 10. It will be seen from the side view that the levers 6 protrude in a posterior direction, i.e. to the rear in the direction of walking, from the connection site on the receiving device 17, such that a lever arm is formed, with the result that, during a pivoting movement of the prosthesis socket 10 about the socket pivot axis 14, the force transmission element 5, which is mounted pivotably at the proximal bearing point 15 and the distal bearing point 25, is moved downward substantially rectilinearly. The distal bearing point 25 is likewise arranged posteriorly on the carrier 26 in the direction of walking, i.e. behind the knee joint pivot axis 23, such that the force vector from the proximal bearing point 15 to the distal bearing point 25 does not intersect the knee joint pivot axis 23. In this way, a moment is generated about the prosthetic knee joint pivot axis 23, such that the top part 21 is pivoted about the prosthetic knee joint pivot axis 23 relative to the bottom part 22.

[0035] The pivoted position is shown in FIG. 4.

[0036] The fastening device 1 allows the effective rotation point of the knee to be set to the anatomical height, by way of the socket pivot axis 14. Conventional prosthetic knee joints 20 can also be used for patients with long thigh stumps, in particular for patients on whom knee disarticulation has been carried out. Moment transfer takes place from the fastening device 1 to the conventional prosthetic knee joints. The coupling of the prosthesis socket 10 to the fastening device 1 is effected either via a conventional pyramid adapter or via laminated binding points, by way of which the branches can be connected medially and laterally to the prosthesis socket 10, if appropriate using spacer pieces.

[0037] FIG. 5 shows the variant according to FIGS. 3 and 4 in a rear view. It will be seen from FIG. 5 that the prosthesis socket 10, at its distal end, is secured centrally to the bracket 7 via a pyramid adapter as receiving device 17. The embodiment of the receiving device 17 as a pyramid adapter has the advantage that conventional prosthesis sockets 10 can be used which are already configured for direct securing to a prosthetic knee joint. Alternatively, the prosthesis socket 10 can be coupled by other fastening devices to the bracket 7, or by other devices to the one or more force transmission elements 5. In the illustrative embodiment shown, the bracket 7 is continued past the socket pivot axis 14 in the proximal direction, such that the levers 6 form a connection between the socket pivot axis 14 and the bearing points 15. In this way, a force coupling is provided between the prosthesis socket 10 and the proximal bearing points 15, such that, during a pivoting movement of the prosthesis socket 10 about the socket pivot axis 14, the branches 51, 52 of the force transmission element 5 exert a distally directed force on the distal bearing points, on account of the pivotable bearing at the bearing points. The carrier 26, which as a crosspiece connects the medial and lateral branches 51, to each other, is in this way pivoted about the prosthetic knee joint axis 23.

[0038] The distal holder is fastened releasably to the bottom part 22 by bolts or screws 200. A damper device, as shown in FIG. 1, is not shown in the variant according to FIGS. 3 to 5. Such a damper device can be fastened to the top part 21 and the bottom part 22. The struts 3 are secured medially and laterally to the bottom part 22 via the screws or bolts 200. Instead of being fastened by form-fit engagement, the struts 3 can also be clamped on the bottom part 22.