Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Reexamination Certificate
1999-04-14
2001-04-03
Millin, Vincent (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
C623S020140
Reexamination Certificate
active
06210443
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to knee prosthetics. In particular, the present invention relates to prosthetics that incorporate a femoral prosthetic component designed to be fixed to the furthest or lower extremity of the femur; a tibial prosthetic component designed to be fixed to the nearest or upper extremity of the tibia, and at least one intermediate meniscoid prosthetic component which has at least one upper concave surface which works together with a lower convex condyloid surface of the femoral component, by sliding.
BACKGROUND OF THE INVENTION
Amongst these prosthetics, the invention concerns those which contain a mobile meniscoid component, in contract to those prosthetics in which this meniscoid component is fixed with regard to the tibial component. The mobile meniscoid component can be moved with respect to the tibial component following a general ante-posterior movement, being guided, for example, by a rail, and eventually following an additional limited rotational movement around an axis, which is perpendicular to the direction of the movement.
Amongst these prosthetics incorporating a mobile meniscoid component the invention applies just as well to so-called uni-compartmental ones, that is to say—prosthetics designed to replace the articulation of a single condyle, as to so-called three-compartmental prosthetics, that is to say, prosthetics designed to replace articulation of two condyles, whilst maintaining the rear crossed ligament.
The invention aims to provide a prosthetic of the type which restores the anatomical antero-posterior slope of the upper side of the tibial embase, whilst maintaining maximum preservation of the major bones and simplifying the cut or cut away of the tibia, which is achieved chiefly on a perpendicular plain on the anatomical axis of the tibia.
SUMMARY OF THE INVENTION
According the present invention, there is provided a knee prosthetic, incorporating a femoral prosthetic component designed to be fixed to the furthest or lower extremity of the femur, a tibial prosthetic incorporating an embase of which the lower surface is flat and is designed to lean on a close resection plane of the tibia, and at least one intermediary mobile meniscoid prosthetic component at least in the anteposterior direction and involving a lower surface configured to work together by sliding with one complementary upper surface of the tibial component, and at least one upper concave surface configured to work together by sliding within one lower convex condyloid surface of the femoral component, wherein the upper surface of the tibial component and the lower surface of the meniscoid component are flat and sloping in the same angle from the top at the rear towards the front, with respect to the lower surface of the embase.
Thus, the prosthetic which is the subject of the invention restores not only the anatomical mobility of the menisci, but also the ante-posterior anatomical gradient of the knee, whilst also maintaining the major bones to a maximum and allowing a simple adjustment of the plane of the tibial resection, for example at ninety degrees to the anatomical or mechanical axis of the tibia.
For example, the angle of tilt of these flat surfaces has a value between one and ten degrees, preferably five, with respect to a perpendicular plane to an anatomical axis of the tibia.
Following one method, these two flat surfaces are only inclined in an ante-posterior direction, that is to say, with no gradient in the medio-lateral direction.
Following a second method, these flat surfaces both have a gradient in the medio-lateral direction, the said surfaces being inclined toward the bottom and towards the sagittal or anteposterior plane, of the tibia. In this case, for a three-compartmental type of prosthetic the meniscoid component is in two different parts each one of which may be moved, with regard to the tibial component, at the same time in the ante-posterior direction and invention the medio-lateral such that in the first method, the meniscoid component can be in one part or in two different parts.
In the case of a uni-compartmental prosthetic, the meniscoid component is clearly evident in a single part since it replaces a single natural meniscus.
In both the methods mentioned above, for a three-compartmental prosthetic, the meniscoid component, whether it is made up of a single or two different parts, includes two prosthetic menisci, external and internal both co-operating respectively with two prosthetic condyles, external and internal of the femoral component.
One advantageous characteristic of the invention is that in the case of a three-compartmental prosthetic, the rear edge of upper concave surface of the external prosthetic meniscus is higher than the rear edge of the upper concave surface of the internal prosthetic meniscus, with respect to a perpendicular plane to the tibia axis. This difference in height of the posterior edges of the two prosthetic menisci is between 1 mm and 4 mm, preferably 2 mm.
Another advantageous characteristic of the invention, also in the case of a three-compartmental prosthetic, is that the rear edge of upper concave surface of the external prosthetic meniscus is situated further back than the rear edge of the upper concave surface of the internal prosthetic meniscus, in respect of the medio-lateral plane of the tibia. This distance between the rear waves of the two prosthetic menisci is between 1 mm and 4 mm, preferably 2 mm.
For example, the upper concave meniscoid surface of the meniscoid component and the lower convex condyloid surface of the femoral component are toric surfaces which leads to an arc of a circle being generated.
REFERENCES:
patent: 4936853 (1990-06-01), Fabian et al.
patent: 4963453 (1990-10-01), Noesberger et al.
patent: 5047057 (1991-09-01), Lawes
patent: 5047058 (1991-09-01), Roberts et al.
patent: 5879392 (1999-03-01), McMinn
patent: 0 194 326 A1 (1986-09-01), None
patent: 2 676 916 (1992-12-01), None
patent: 2 756 483 (1998-06-01), None
patent: 2 312 166 (1997-10-01), None
patent: WO 95/17860 (1995-09-01), None
patent: WO 98/02116 (1998-07-01), None
Barba Laurent
Barthelemy Jean-Paul
Biegun Jean-François
Catonne Yves
Hummer Jacques
Aesculap
Millin Vincent
Renner Kenner Greive Bobak Taylor & Weber
Stewart Alvin
LandOfFree
Knee prosthetics does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Knee prosthetics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Knee prosthetics will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2435160