Orthopaedic Implant

Abstract

For an orthopaedic implant, an insert body of a non-metallic material is arranged in a socket of an originally metallic material. The insert body consists of a ceramic based on zirconium dioxide, aluminum oxide or a mixed oxide ceramic, whereas the socket is preferably produced of pure titanium or a titanium alloy, for example Ti-6Al-4V, provided with a plurality of small holes and preferably embodied as a mesh or net structure. The titanium net structure is firstly imparted with ceramic properties with the aid of a silicate glass solder solidified or hardened in a ceramic firing, the subsequent connecting or joining between the ceramic insert body and the now also ceramic titanium socket is achieved by means of a glass solder which is based on silicon dioxide (SiO.sub.2) and which connects or joins the two components with one another.

Claims

1. An orthopaedic implant for the replacement of joints, with an insert body of a non-metallic material of a ceramic and with a metallic socket of a titanium material that at least partially surrounds the insert body, characterized in that the surface of the metallic socket (2, 3) is pre-coated with a silicate glass solder that is hardened in a ceramic firing, and its subsequent soldering with the outer surface of the insert body (1) is achieved via a glass solder (9) based on silicon dioxide (SiO.sub.2), which joins the two components with one another, and the metallic socket is embodied as a mesh or net structure (2) or as a perforated metal sheet (3), respectively having a plurality of small holes penetrating therethrough.

2-4. (canceled)

5. The orthopaedic implant according to claim 1, characterized in that the insert body (1) consists of a ceramic based on aluminum oxide ceramic.

6. The orthopaedic implant according to claim 1, characterized in that the insert body (1) consists of a ceramic based on zirconium oxide ceramic.

7. The orthopaedic implant according to claim 1, characterized in that the insert body (1) consists of a ceramic based on mixed oxide ceramic.

8. The orthopaedic implant according to claim 1, characterized in that the metallic socket (2, 3) consists of titanium.

9. The orthopaedic implant according to claim 1, characterized in that the metallic socket (2, 3) consists of a titanium alloy.

10. The orthopaedic implant according to claim 1, spacers (15) provided between the metallic socket (2, 3) and the insert body (1).

Description

[0009] In the following the invention will be explained in further detail in connection with an example embodiment illustrated in the drawing. It is shown by:

[0010] FIG. 1 a ceramic body for a hip joint endoprosthesis in a perspective illustration,

[0011] FIGS. 2 and 3 two different embodiments of an originally metallic socket, which surrounds the ceramic insert body, and which is respectively provided with a plurality of small openings,

[0012] FIG. 4 the joining of a ceramic insert body with the mesh or net structure,

[0013] FIG. 5 a schematic illustration of directly allocated socket and insert body, and

[0014] FIG. 6 an illustration according to FIG. 5 with spacers between socket and insert body.

[0015] The illustration according to FIG. 1 shows a ceramic insert body 1 for a hip joint endoprosthesis, which is inserted in a shell that is embodied originally as a metallic socket or cup 2, 3. The insert body 1 consists of either a pure aluminum oxide ceramic, a zirconium oxide ceramic or of a so-called mixed oxide ceramic of aluminum and zirconium oxide, if applicable with an additive of yttrium oxide, and is provided with a central stopper 6, which is formed on it in a one-piece integral manner, and which extends through a central through-bore of the cup 2, 3, and which, among other things, serves for the flowing-away or discharge of excess solder. In the case of the example embodiments of the invention illustrated here, the material of the cup 2, 3 originally involves the titanium alloy Ti-6Al-4V (titanium grade 5).

[0016] In the case of the example embodiments of the invention illustrated in the FIGS. 2 to 4, the titanium cup or shell comprises a plurality of small openings, and can be embodied as a mesh or net structure as illustrated in FIG. 2, or in the manner of a three-dimensional perforated metal sheet 3 according to FIG. 3. By means of an airbrush technique 12, 13 or with the aid of another suitable technique, a thin but covering layer of a silicate glass solder 8 is applied onto the structure, and this is subsequently subjected to a ceramic firing. In that regard it is important that all areas of the titanium cup or shell 2, 3 are coated with the solder 8 and are subjected to a ceramic firing, which then produces a drop-free uniform layer that is solidified or hardened.

[0017] Thereafter, the cup or shell 2, 3 is set onto the ceramic insert body 1, either directly or via spacers 14, and is connected or joined therewith via a glass solder 9 based on SiO.sub.2, Al.sub.2O.sub.3, K.sub.2O and Na.sub.2O in a soldering process, in which the temperature is preferably maintained under 850 C. in order to avoid a phase transition of the titanium. Before this soldering process, the webs and the inner rims of the mesh or net structure or the perforated metal sheet structure 2, 3 are coated or covered with the glass solder 9, for example with a paintbrush 14, as this is illustrated in the arrangement according to FIG. 4. In that regard, the spacing distance of the two parts, that is to say of the insert body 1 and of the titanium structure 2 or 3, relative to one another is determined by the layer thickness of the glass solder 9 applied onto the stated parts of the titanium structure 2, 3 and onto the outer surface of the ceramic insert body 1. The connection or joining between the insert body 1 and the structure of the titanium shell 2 or 3 produced by this soldering process is now suitable for a cement-free fixing of the implant in the body of a patient.

[0018] The geometry of a sliding tribologic pairing of a knee endoprosthesis is in principle significantly more complex than that of a hip joint, but nonetheless implants of the above described type can be produced and utilized also in this case. Components for the spine, for small joints can also be produced or fabricated of such implants. In each case, it is decisive that the titanium structure at first takes on ceramic characteristics with the aid of a silicate glass solder, so that all metallic abrasive wear particles are surely or reliably enclosed, especially no titanium ions can be released, and later at most silicon wear can be detected, whereby the connection or joining between the ceramic insert body and the similarly ceramic titanium socket is achieved by means of a silicate glass solder, which is suitable for connecting or joining both ceramic components with one another.