The invention relates to a prosthesis socket with an open proximal end for accommodating an amputation stump, an inner wall and an outer wall.
This type of prosthesis socket has been known from the prior art for many years and is used for various prostheses and amputation stumps. They act as a connecting element between the amputation stump of the patient and the prosthesis, which replaces a body part of the patient that has been amputated. In the case of leg prostheses in particular, prosthesis sockets are subjected to a significant mechanical load. This is true for both upper leg prostheses and lower leg prostheses.
To ensure that it is both comfortable to wear and suitably safe for the patient, the socket must be securely arranged on the amputation stump. A range of possibilities for achieving this are known from the prior art. A so-called liner is often pulled over the amputation stump before the combination of amputation stump and liner is inserted into the prosthesis socket. The liner can interact with a recess provided for this purpose in the prosthesis socket via a fastening pin, which is usually located at the distal end of the liner. As an alternative, a negative pressure is created between the liner and the socket in a confined volume, securing the socket to the liner and thus to the amputation stump.
The wearer of the prosthesis socket that uses the prosthesis to walk must raise the entire prosthesis, including socket, during the swing phase of each step and swing it forwards. The prosthesis socket must not make the wearer feel that the connection between socket and amputation stump is not secure. At the same time, the prosthesis socket must feature a connection element for further prosthesis elements at its distal end, for example a prosthetic knee or a lower leg with an ankle and foot arranged thereon. This connection, created via the connection element, must safely transfer the forces that occur during walking and make the wearer feel that it is secure.
The various elements of a prosthesis socket are therefore designed to be relatively solid so they can withstand the loads that occur. As a result, the prosthesis socket in particular is heavy, rendering it less comfortable to wear.
Modern prosthesis sockets are often produced using carbon fiber composite materials. Such sockets are light yet still offer significant mechanical stability, making them very well-suited to meet the demands of a prosthesis socket. In recent years, prosthesis sockets have also been produced using an additive manufacturing process, for example by means of a 3D printer. This enables new designs and shape of prosthesis socket that could not be produced using conventional production methods, such as carbon fiber composite materials.
WO 2017/012888 A1 discloses a production method for a prosthesis socket in which an inner socket is first produced using a 3D printer. However, the material used is unable to absorb and withstand the mechanical loads of a prosthesis socket for treating a lower limb. To resolve this issue, additional reinforcement elements are applied to points that are particularly subjected to loads on the outside of the inner socket produced in this way. However, the production method becomes more complex as a result, as it requires multiple steps and several different materials.
The invention therefore aims to prevent or at least reduce the disadvantages of the prior art, and to propose a prosthesis socket and method for its production that is light and able to withstand the loads.
The invention solves the problem addressed by way of a prosthesis socket according to the preamble of claim 1, characterized in that at least one cavity is arranged between the inner wall and the outer wall, through which at least one internal element extends, the at least one internal element being designed as a single piece with the inner wall and/or outer wall.
The design of the prosthesis socket according to the invention with a cavity reduces the weight, so that the prosthesis socket and thus the entire prosthesis is lighter. At the same time, the internal element that extends through the cavity increases stability. The internal element is designed as a single piece with the inner wall and is therefore produced in the same step of the method as the respective wall. Preferably, the inner wall, the outer wall and the at least one internal element are designed as a single piece.
The cavity is situated between the inner wall and outer wall, and is not the space in which the amputation stump can be accommodated. The cavity is preferably closed, so that there is no connection between the interior of the cavity and the surrounding area. The inner wall of the prosthesis socket is preferably at least roughly designed according to the shape of the amputation stump to be accommodated. It is essentially cup-shaped and the prosthesis socket preferably has a closed distal end. The cavity is preferably located distally to the distal end of the inner wall. The at least one cavity is preferably restricted in the proximal direction by the inner wall of the prosthesis socket and in all other directions by the outer wall of the prosthesis socket. It can be designed to be rotationally symmetric about a longitudinal axis; however, this is not essential. At the distal end of the prosthesis socket there is preferably a connection means for a further distal prosthesis component. The part of the prosthesis socket on which this connection means is located also forms part of the prosthesis socket and preferably restricts the at least one cavity in the distal direction. In terms of the cavity, the inner wall and outer wall have an inner side that faces towards the cavity. The at least one internal element is arranged in this inner side of the respective wall.
The at least one internal element extends through the at least one cavity. It not only protrudes into the at least one cavity, but passes through it, preferably completely. It preferably connects two walls that surround and restrict the at least one cavity. It can extend between the inner wall and the outer wall or connect multiple positions or points on a single wall, i.e. the inner wall or outer wall, to each other.
The at least one internal element is preferably a support element, which preferably extends from the inner wall to the outer wall. Such a support element is preferably a strut, a rod or a rod-like element, meaning that it has a greater extension in the longitudinal direction, i.e. from the inner wall to the outer wall, than in the other spatial directions. The cross-section may be circular, oval, square, triangular, polygonal or irregular. A support element may also be arranged between two points or positions on a single wall, i.e. the inner wall or the outer wall, and connect these points or positions with each other. The cross-section may vary along the course of the support element, in particular the diameter can change so that it is larger, for example, in the area of the connection between the wall and the support element. Of course, the cross-section may also be constant over the course of the support element.
It is especially preferable if the at least one support element at least also extends in the proximal-distal direction. The longitudinal direction of the at least one support element thus also has at least one component in this direction, this component preferably being the largest component. In this case, the at least one support element extends further in the proximal-distal direction than in all other directions.
Preferably, at least 25, preferably at least 100, especially preferably at least 500 support elements extend in the at least one cavity, wherein several, but preferably all, of them extend from the inner wall to the outer wall. This enables an even distribution of load on the various support elements and the stability of the prosthesis socket can be further optimized.
In a preferred embodiment, at least one support element is perpendicular to the inner wall and/or outer wall. Particularly preferably, several, most preferably all, support elements are perpendicular to the inner wall and/or the outer wall. This avoids shear moments and tilting moments on the individual support elements, which could otherwise occur when the prosthesis socket is subjected to a load, for example when walking. This also increases the stability of the prosthesis socket. As a result, the number and thickness of the support elements can be reduced, thereby saving on material and weight.
Preferably at least one internal element is a partition element that divides the cavity into two partial cavities. Such a partition element is preferably arranged exclusively on the outer wall of the prosthesis socket. In contrast to a support element, a partition element is preferably flat, i.e. it has a greater extension in two directions perpendicular to each other than in the third spatial direction, which is perpendicular to the first two directions. The at least one partition element preferably extends in one plane, which is essentially perpendicular to the proximal-distal direction. In this case, the at least one partition element is preferably arranged exclusively on the inner side of the outer wall.
The at least one partition element preferably features at least one opening, which connects the two partial cavities to each other. Particularly preferably, at least one support element extends through this opening.
In an alternative embodiment of a partition element, the partition element is designed to be three-dimensional, i.e. it is not exclusively flat in design. It may be designed as a hollow tube, curved surface or otherwise. By using a partition element with a closed cross-section contour, such as a tube, the at least one cavity is divided into two partial cavities, one of which is found inside the partition element and one outside. The cross-section contour may be circular, oval, square, triangular, polygonal or irregular. It is also possible for the contour to change in shape, size and/or contour along a longitudinal direction of the partition element formed in this way. A partition element designed in this shape preferably extends essentially along the proximal-distal direction, so that the partial cavities created by the partition element also extend in this direction. The partition element is preferably arranged between the inner wall in the proximal area of the cavity and the outer wall in the distal area of the cavity.
In a preferred embodiment, the prosthesis socket has a plurality of partition elements, so that the at least one cavity is divided into a plurality of partial cavities. The partition elements preferably run parallel to one another and, particularly preferably, these partial elements are designed to be flat and, more preferably, run perpendicular to the proximal-distal direction. This results in the creation of chambers that considerably increase a bending stiffness of the prosthesis socket in this area.
Preferably, at least one connection means for a distal prosthesis component is arranged at a distal end of the prosthesis socket. The connection means is preferably arranged on the outer wall of the prosthesis socket. The distal prosthesis component is, for example, a prosthetic knee, a lower leg tube or a prosthetic foot, preferably with an artificial ankle joint. In particular, but not only in the case of lower leg prosthesis sockets, it is beneficial to enlarge an expansion of the prosthesis socket in the distal direction to such an extent, i.e. to extend the prosthesis socket in this direction to such an extent, that a prosthetic foot and/or artificial ankle joint can be positioned directly on the connection means. This reduces the number of prosthesis components required and simplifies assembly of the prosthesis. For example, a separate lower leg tube is no longer needed. The at least one cavity is at least also located in the area of the prosthesis socket extended in this manner, said cavity preferably being divided into multiple partial cavities or chambers by at least one, but preferably multiple, partition elements.
If the prosthesis socket features multiple support elements, imaginary extensions of the support elements run through the connection means. Particularly preferably, they meet at a single point within the connection means. In this case, the force transmission through the support elements takes place directly into the connection means and thus directly into a prosthetic component arranged on the connection means. This also renders it possible to prevent or at least reduce shear moments or tilting moments.
The prosthesis socket is preferably a prosthesis socket for a prosthesis for treating a lower limb, preferably for a lower leg prosthesis.
A prosthesis socket of the type described here preferably has at least a first insert element, which has a contact surface that is designed to at least partially, but preferably completely, correspond to at least one part of the inner wall of the prosthesis socket. Such an insert element is also beneficial in other prosthesis sockets that do not have a cavity and/or internal element, for example. Therefore, such an insert element in combination with the features of the preamble of the original claim 1 constitutes a separate invention that can be used with or without the features of the prosthesis sockets described here. An insert element is used when the amputation stump loses volume over time and the original prosthesis socket no longer optimally fits the amputation stump. Then an insert element is produced, which must be laboriously adapted, for example ground, to the desired shape. This time-consuming and therefore cost-intensive.
With the present invention, this becomes easier. The prosthesis socket is preferably produced in an additive manufacturing process, such as a 3D printing process, so that its contours and shaped are stored electronically. Therefore, a first insert element can easily be produced, in particular also 3D printed, the contact surface of which is optimally adapted to the inner wall of the prosthesis socket, preferably its outer side opposite the inner side. The insert element can preferably be placed with its entire surface against the outer side of the inner wall of the prosthesis socket. The insert element is thus introduced into the cavity, which is provided for accommodating the amputation stump. Complex post-treatment is not necessary. In the desired position, the insert element is glued or otherwise fixed to the inner wall of the prosthesis socket. Preferably, the insert element then forms a uniform and, in particular, continuous, i.e. stepless, surface with the part of the outer wall of the inner wall of the prosthesis socket that is not covered by it.
The prosthesis socket preferably has at least a second insert element that features a contact surface, which is designed to correspond to the inner wall of the prosthesis socket and/or a surface of the first insert element that is opposite the contact surface. The prosthesis socket is preferably delivered with several such insert elements, preferably forming a set with said elements. Alternatively or additionally, insert elements with the appropriate material thickness may be produced individually. If a permanent change in volume of the amputation stump occurs, particularly a reduction in volume, this can be compensated by the careful selection of one or multiple insert elements.
The invention also solves the problem addressed by way of a method for producing a prosthesis socket as described here, wherein with said method:
To be able to determine the directions of the forces expected to occur during use, a model of the prosthesis to be produced is preferably generated, wherein said model can be edited in an electronic data processing device. It is preferably stored in an electronic data storage device. With the aid of a saved model, a simulation unit of the electronic data processing device then simulates the forces that occur and stores their values and directions. On the basis of this data, a modelling unit of the electronic data processing device models the optimal positions and orientations of the support elements required. In addition, the thickness, cross-section, course and/or number of support elements can be used as an optimization parameter of the modelling unit. The electronic data processing device then transmits control commands to the additive manufacturing installation, for example the 3D printer, and controls it in such a way that the modelled prosthesis socket is printed.
Preferably, the prosthesis socket is at least partially produced by means of an additive manufacturing process, for example using a 3D printer, the at least one support element in particular being produced using additive manufacturing, for example printed.
In the following, some examples of embodiments of the present invention will be explained in more detail by way of the attached figures:
They show
In another sectional representation,
The left-hand part of
This is shown in
2 prosthesis socket
4 proximal end
6 distal end
8 connection means
10 lower leg tube
12 prosthetic foot
14 virtual pivot axis
16 heel strike point
18 point
20 inner wall
22 outer wall
24 cavity
26 support element
28 dashed line
30 partition element
32 opening
34 partial cavity
36 insert element
38 contact surface
40 rim
42 dashed line
44 side
46 recess
48 borehole
50 pyramid adapter
52 depression
54 stem
56 recess
58 bolt
60 slit
62 distal side
64 hole
66 bore
Number | Date | Country | Kind |
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10 2019 134 986.9 | Dec 2019 | DE | national |
This is a national phase application of International Application No. PCT/EP2020/086220, filed 15 Dec. 2020, which claims the benefit of German Patent Application No. 10 2019 134 986.9, filed 18 Dec. 2019, the disclosures of which are incorporated herein, in their entireties, by this reference.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/086220 | 12/15/2020 | WO |