AN ORTHOPAEDIC COVERING MATERIAL AND AN ARTIFICIAL LIMB SOCKET MADE FROM SAID MATERIAL

Abstract: An orthopaedic covering material and an artificial limb socket (3) made from this material, comprising a thin, flex­ ible leather inner layer (4), a layer (5) of resilient thermo­ plastic material attached to the exterior of said inner layer, said resilient layer having perforations in predetermined regions occupying a substantial part of the surface of the material. The inner layer is attached to the resilient layer along the portions of said layer located between the per­ forated regions. Optimally, a leather outer layer (6) is pro­ vided on the exterior of the resilient layer.

Description: Title: An orthopaedic covering material and an artificial limb socket made from said material. This invention relates to an orthopaedic covering material made from a thin, flexible leather inner layer and a layer of resilient material attached to the exterior of said inner layer. This invention relates more in particular to an artificial limb socket made from such orthopaedic covering material and also relates to a holder for such an artificial limb socket. Orthopaedic covering material, which often abuts, under pressure, against the wearer's skin often includes a resilient layer to increase his wearing comfort, in particular when the covering material is used as a transition between the skin and a mechanical aid, such as a prosthesis. To prevent shifting of the inner layer relative to the resilient layer, it is desirable that the two layers are attached to one another. Such orthopaedic covering material for use in a prosthesis, a so-called artificial limb socket, is described in US patent 1,861,311. This socket aims at providing an optimally comfortable fit of the sensitive leg or arm stump in the artificial limb formed of rigid material. To this end, the resilient layer consists of layers of cork, sponge rubber and cork successively glued together. In the prior art socket, a leather outer layer is applied to the outside of the resilient layer. The prior art socket is destined for an artificial limb connected through a brace construction to the upper leg or the upper arm, with the possibility of an open lower end of the socket. Moisture and heat generated in the socket during the wear of an artificial limb may escape along the underside of the limb but not via the various layers of the socket, since this is moisture-impervious owing to the various adhesive layers. Moreover, the layers of sponge rubber and cork, under the influence of moisture, in particular perspiration, would rapidly lose their resilient properties. So-called suction prostheses have been known for quite some time which lack a special brace construction therefor; the prosthesis is braced by the leg or arm stump itself, in that a subatmospheric pressure prevails in the socket forming the joint between the prosthesis and the leg or arm stump. Such prostheses have been found to be comnfortable tower but have the drawback that during wear moisture and heat produced in the socket cannot escape. The socket should in fact fully enclose the stump with a view to the creation of the above subatmospheric pressure. The socket disclosed in US patent 1,861,311 does not provide a solution for suction prostheses either, since the various layers of the prior art socket are glued onto each other and hence are moisture-impervious. It is an object of this invention to provide an orthopaedic covering material, in particular for an artificial limb socket, which is highly suitable for a suction prosthesis and which moreover is moisture- and heat-pervious, so that the prosthesis becomes appreciably more comfortable to wear. This invention provides to that end an artificial limb socket of the above type wherein the resilient layer consists of thermoplastic material having perforations in predetermined regions occupying a substantial part of the surface of the material and wherein the inner layer is attached to the resilient layer along the portions of said layer located between the perforated regions. Preferably, a multiplicity of similar perforated regions are provided in the thermoplastic material, which regions are equidistantly spaced apart. Owing to the construction of the resilient layer for the artificial limb socket according to this invention and the specific method of attachment, in particular the gluing, of the leather inner layer to said resilient layer, there is produced a socket having very good properties, in particular as regards the possibility of heat and moisture discharge. Heat and moisture can readily reach the resilient layer via the thin leather inner layer. Since the inner layer is glued to the resilient layer over a specific small portion of its surface only, said adhesive layer does not constitute an impediment to the transport of heat and moisture via the leather to the resilient layer, while, moreover, the perforated regions in the resilient layer, ensuring the actual heat and moisture discharge, lie entirely free against the inner layer without any glue being present between these regions and the inner layer. The moisture and heat from the resilient layer can be discharged by means of the perforations to an outer layer. Said outer layer is preferably not glued to the resilient layer at all, so that moisture and heat discharge is not impeded in any way whatever. It is observed that US patent 2,578,019 discloses an artificial limb made from an absorbent material, while cushions of resilient, spongy material are provided in the limb itself to support the leg stump with the socket, said cushions including vent holes. However, the socket is not attached to the cushions, so that the problem underlying the present application is absent. Moreover, the prior art artificial limb socket is destined for a conventional artificial limb and not for a suction prosthesis. Although the artificial limb socket according to this invention can be used very well in conventional prosthesis that are attached to the upper arm or the upper leg by means of a brace construction, the socket according to this invention is highly suitable for use in suction prostheses. In a suction prosthesis, no matter how well the socket fits the leg stump, there will always be some movement of the leg stump relative to the socket when the leg is moved. For instance, when the leg is lifted, the upper leg will slide out of the socket to some extent, while when the leg is put down again, the leg stump will be pressed downwardly in the socket. This movement of the leg stump in the socket provides a particularly favourable effect in the prosthesis socket according to this invention, as when the leg is put down, an outwardly directed force is exerted by the air present in the socket on the heat and moisture contained in the socket, so that this will be pressed through the inner layer towards the resilient layer and can be discharged through the perforations in the resilient layer and through the outer layer. In this manner, moisture is automatically pressed outwardly at each step, thus ensuring a very good discharge of the moisture and also of the heat. When the wearer of the prosthesis is not walking or when the prosthesis is attached to a limb that is not intensively moved, the moisture and heat produced can nevertheless escape, be it less quickly, since the limb located within the socket always exerts a certain pressure in the lining of the socket. The leather inner layer of the socket according to this invention therefore ensures on the one hand an adequate air-tight seal between the socket and leg stump, while on the other hand said leather layer enables the transport of moisture and heat to the resilient layer. The use of a leather outer layer is desirable to give the socket a more pleasing appearance, to protect the resilient layer from damage and also to further improve the air-tightness of the socket, but is not really necessary. Preferably, the prosthesis socket includes a zipfastener enabling the leg or arm stump to be introduced into the socket without the exercise of force. when, as is the case with the prior art sockets, the stump has to be put in the socket with some force, this results in the strangulation of blood vessels, irritation of the skin and eventually even deformation of the stump. A drawback of a zip-fastener is that it adversely affects the airtightness of the socket, which is undesirable in suction prostheses. To solve this problem, this invention also provides a holder for the socket according to this invention. Said holder is attached to the prosthesis and has a large number of perforations so as not to impede the transport of heat and moisture from the socket. The only place where it is imperforate is where the zip-fastener abuts on the holder wall when the prosthesis is worn. In this manner, the holder wall ensures a proper air-tight seal for the zip-fastener in the socket. In order to maximally facilitate the positioning of the socket in the holder, the holder preferably includes two parts which are hinged together. As a result, the socket can be placed in the holder without the exercise of force, after which the two holder portions can be interlocked. One embodiment of this invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic view of a "below-the-knee" prosthesis containing a socket according to this invention; Fig. 2 is a partly opened view of the socket according to this invention; Fig. 3 is a top view of the material of the resilient layer of the socket; and Fig. 4 is an elevational view of the socket holder according to this invention. In Fig. 1, 1 designates a leg stump to which an artificial limb 2 is fitted. This limb is not shown in detail, since it does not form part of the invention. Between the limb and the leg stump there is provided an artificial limb socket 3, which is shown in greater detail in Fig. 2 and comprises an inner layer 4, formed of a thin, flexible leather pleasant to the skin, a resilient layer 5 to be described hereinafter and - preferably a leather outer layer 6. Fig. 3 shows in greater detail the structure of the resilient layer 5. As shown, the resilient layer, made from a suitable thermoplastic material, includes a plurality of regions 7, circular in the figure, each region having a large number of perforations 8. The leather inner layer 4 is attached to the resilient layer 5 preferably by means of adhesive, with the adhered regions being located exclusively between the regions 7 of the resilient layer 5. It is thus ensured that no adhesive is present between inner layer 4 and regions 7, so that moisture can be discharged optimally via inner layer 4 through the perforations in the regions 7. Although the regions 7 are shown in Fig. 3 to be of circular configuration and uniformly distributed over the resilient layer 5, it is naturally possible to provide differently formed regions with possibly different sizes and different quantities of perforations in the resilient layer. Symmetrically arranged regions with equal numbers of perforations, however, are simpler to manufacture. As shown in Fig. 3, the artificial limb socket preferably includes a zip-fastener 9, which appreciably facilitates the positioning of the socket around the stump. Fig. 4 diagrammatically shows a holder which is highly suitable for use in the socket according to this invention. Holder 10 is basically cylindrical and is attached to the top end of the artificial limb. The holder is open at its top and closed at its bottom. In order to maximally facilitate the insertion of the socket into the holder, the holder includes two hingedly interconnected portions 10' and 10". when portion 10" is folded downwards around the hinge 11, the stump with the socket can be placed conveniently in the holder without any force being required to be exercised, after which the portion 10" can be lifted again and be attached to the portion 10' by suitable means, e.g. pins, not shown, passed through eyelets 12, to confine the stump and the socket within the holder. In order not to impede the discharge of moisture and heat from the socket, the holder wall is provided with a plurality of perforations 13. This wall is only imperforate where, when the artificial limb is worn, the zip-fastener 9 abuts against the holder wall. Thus, any leakage of air through the zip-fastener, which is undesirable in suction prostheses, is counteracted, as the holder wall provides the required sealing adjacent the zip-fastener. Although this invention has been described with particular reference to its use for an artificial limb socket, the structure of the material, consisting of a leather inner layer, a perforated resilient layer of thermoplastic material and a leather outer layer, with the gluing taking place only in the non-perforated regions, is also highly suitable e.g. as a material for a corset, since the discharge of moisture and heat constitutes a problem also in such an application. In general, the material can be used in all places where material comes to bear, under pressure, on the human skin.

Claims: CLAIMS 1. An orthopaedic covering material comprising a thin, flexible leather inner layer, and a layer of resilient material attached to the exterior of said inner layer, characterized in that the resilient layer consists of thermoplastic material having perforations in predetermined regions occupying a substantial part of the surface of the material and that the inner layer is attached to the resilient layer along the portions of said layer located between the perforated regions. 2. An orthopaedic covering material according to claim 1, characterized in that the perforated regions in the thermoplastic material are distributed uniformly over the surface of the material and have a round configuration. 3. An artificial limb socket according to claim 1 or 2, characterized in that the leather inner layer is attached to the resilient layer by gluing. 4. An orthopaedic covering material according to any of claims 1-3, characterized in that a leather outer layer is attached to the resilient layer. 5. An artificial limb socket, characterized in that it is made from orthopaedic covering material according to any of claims 1-4. 6. An artificial limb socket according to claim 5, characterized in that the socket is closed at its bottom. 7. An artificial limb socket according to claim 6, characterized in that there is provided a zip-fastener extending from the open top of the socket to adjacent the closed bottom thereof. 8. A holder for an artificial limb socket according to claim 6 or 7, characterized in that the holder has a substantially cylindrical shape and is closed at its bottom and open at its top, the wall of the holder containing a multiplicity of perforations, and that the holder includes two hingedly interconnected portions, each portion occupying approximately half the cylindrical surface of the holder. 9. A holder according to claim 8 for an artificial limb socket according to claim 7, characterized in that the holder wall has an imperforate portion at the position where, in use, the zip-fastener of the socket abuts on said wall. 10. A thermoplastic sheet material including perforated regions occupying a substantial part of the surface area of the material, and evidently intended for use as an orthopaedic covering material according to claim 1.

Inventors: JONGENENGEL, CORNELIS DIRK
Applicants: JONGENENGEL, CORNELIS DIRK
Application year: 1985
Main classification: A61F2
IPC codes: A61F2