Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Reexamination Certificate
1998-01-16
2001-04-10
Milano, Michael J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
Reexamination Certificate
active
06214051
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a knee-joint endoprosthesis.
Known from WO 95/23567 is a knee-joint endoprosthesis having a metallic femoral part anchored in the femur that articulates with a tibial part made of polyethylene which is anchored in the tibia bone. The articulating surface of the femoral part is formed by a ceramic structural member that is connected to the femoral part in mechanically stable manner.
SUMMARY OF THE INVENTION
The object underlying the invention is to improve a knee-joint endoprosthesis in such a way that the attachment of the ceramic structural member to the femoral part is optimised.
In one embodiment according to the invention the ceramic structural member is anchored on the femoral part by means of a conical clamping device. To this end a conical slot is expediently produced in the femoral part, into which slot the conical lateral surfaces of the structural member are inserted. The angle of the conical clamping device preferably amounts to between 5° and 20°. The larger the angle, the more easily the structural members can be removed during a further operation, even after an implantation.
In a preferred embodiment the conical clamping device is disposed only in the region above what is the loading zone the knee is extended.
In another preferred embodiment the conical clamping device extends over the entire region of the articulating surface.
In an alternative embodiment the structural member is anchored on the femoral part by means of at least one fixing screw. A conical clamping device would be dispensed with in this case.
Use is preferably made of two structural members per endoprosthesis. However, use may also be made of only one structural member, which then has two articulating surfaces.
In another alternative embodiment the ceramic structural member is connected to the femoral part in non-detachable manner by shrinking, soldering or welding. Soldering also includes active soldering.
This attachment can be improved if the ceramic structural member is additionally connected to the femoral part by means of a congruent surface arrangement. The latter may be constituted by, for example, interlocking slots and ribs. In an advantageous configuration, the ceramic structural member is additionally connected to the femoral part by means of a slot/spring connection. The latter is particularly expedient when there is shrinking on. When there is a slot/spring connection, a rib on the structural member, for example, projects into a slot in the femoral part, or vice versa. However, many variants of the congruent surface arrangement are possible.
In another alternative embodiment the ceramic structural member is in the form of a layer and is secured or applied by vapour deposition, spray application or such like. The structural member is accordingly a layer in this case. Of course, this layer may also consist of several individual layers. A ceramic material for the layer or the other structural members would be, for example, aluminium oxide.
REFERENCES:
patent: 4227265 (1980-10-01), Frey
patent: 4911721 (1990-03-01), Branemark et al.
patent: 4964869 (1990-10-01), Auclair et al.
patent: 5171282 (1992-12-01), Pequignot
patent: 5197987 (1993-03-01), Koch et al.
patent: 5356436 (1994-10-01), Nonami et al.
patent: 5645602 (1997-07-01), Albrektsson et al.
patent: 5755801 (1998-05-01), Walker et al.
patent: 5782925 (1998-07-01), Collazo et al.
patent: 2705885 (1994-12-01), None
patent: 1527498 (1975-11-01), None
Badorf Dirk
Kalberer Hartmut
Pfaff Hans-Georg
Antonelli Terry Stout & Kraus LLP
CeramTec AG Innovative Ceramic Engineering
Milano Michael J.
Stewart Alvin
LandOfFree
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