WO2010040905A1

WO2010040905A1 - Prosthesis part that can be implanted on a resected end of a bone, and method for implantation thereof

Info

Publication number: WO2010040905A1
Application number: PCT/FR2008/001409
Authority: WO
Inventors: Patrick Hechard
Original assignee: Patrick Hechard
Priority date: 2008-10-09
Filing date: 2008-10-09
Publication date: 2010-04-15

Abstract

The present invention relates to prosthesis parts 100 that can be implanted on the resected end 200 of a long bone 300 with longitudinal axis 400, when this resected end is delimited by a cylindrical surface 210 generated by a generatrix 220 moving parallel to it and perpendicular to the axis 400. The prosthesis part 100 according to the invention is principally characterized by the fact that it has a component 101 comprising an implantation surface 102 congruent with the cylindrical surface 210 of the end 200 so as to superpose itself thereon, and a thin rigid plate 104 which is integral, via one 105 of its edges, with the implantation surface 102, this plate 104 being included in a third cylindrical surface generated by a generatrix parallel to the one that defines the surface 102, such that the thin rigid plate 104 is able to penetrate the end 200 by means of the component 101 being moved in translation in a direction parallel to the generatrix. Advantageous application to the production of the femoral part of a knee prosthesis.

Description

PROSTHESIS PORTION BEING IMPLANTED ON A RESERVED END OF A BONE AND ITS IMPLANTATION METHOD

The present invention relates to the parts of prostheses that can be implanted on a resected end of a bone preferably long, but not necessarily, for example a femur, a tibia, a radius, a humerus, a vertebra, etc., which find a particularly advantageous application, but not only, as femoral parts of total or partial knee prostheses. The present invention also relates to methods for implanting such portions of prostheses.

It is for example known a total knee prosthesis which consists essentially of two implantable prosthesis parts: a femoral part which is essentially composed of a substantially U-shaped part and a tibial portion often called tibial plateau.

The U-shaped piece further comprises, in its bottom corresponding to the base of the U, pads or the like intended to be plugged into corresponding orifices made in the end face of the femur perpendicular to its longitudinal axis after it has been resected.

Also, to implant such a portion of the prosthesis, after the distal end of the femur has been resected to give it the desired shape complementary to the recessed shape of the U, the practitioner is obliged to make orifices in substantially axes. parallel to the longitudinal axis of the femur, then to insert the studs of the prosthesis part so that the U-shaped part, by a translation parallel to the longitudinal axis of the femur, comes to marry at best the resected distal end of the femur.

In order to perform all these operations, the practitioner must first strongly dislocate the knee. However, besides the fact that it requires a relatively complex intervention despite everything, such a dislocation can only be very traumatic for the patient who must then perform long postoperative rehabilitation sessions. Also, it is an object of the present invention to provide a prosthesis portion adapted to be implanted on a resected end of a bone, which at least substantially overcomes the above-mentioned disadvantages of similar prosthetic parts of a prosthesis. the prior art, facilitating the work of the practitioner responsible for its implementation while avoiding a large dislocation of the joints.

The present invention also aims to implement a method for the implantation of such a prosthesis part.

More specifically, the present invention relates to a prosthesis portion adapted to be implanted on a resected end of a bone defined along a longitudinal axis, this resected end being delimited by a first cylindrical surface generated by a generator moving parallel to it. -and evenly perpendicular to the longitudinal axis of said bone, characterized in that it comprises: • a part comprising a second cylindrical surface congruent implantation of said first cylindrical surface of the resected end and intended to be superimposed by sliding in contact with this resected end, and

At least one thin rigid blade integral with one of its edges of said second cylindrical implantation surface, said thin rigid blade being substantially comprised in a third surface of substantially cylindrical shape generated by a generatrix substantially parallel to that which defines said second cylindrical implantation surface, so that said thin rigid blade is able to penetrate into said resected end of the long bone by a translation of said part in a direction parallel to said generator.

Other features and advantages of the invention will become apparent from the following description given with reference to the accompanying drawings for illustrative but not limiting purposes, in which: FIG. 1 represents, in perspective view, an embodiment of a portion of prosthesis according to the invention adapted to be implanted on a resected end of a bone defined along a longitudinal axis, in the application to the realization of the femoral part of a total knee prosthesis,

FIG. 2 represents, in a single illustration in side view and in schematic section, several possible embodiments of a prosthesis part in accordance with the representation according to FIG. 1, while noting however that this illustration may be, to it alone, that of another embodiment, and

FIG. 3 is a perspective view of a portion of another preferred embodiment of a prosthesis portion according to the invention adapted to be implanted on a resected end of a bone defined along a longitudinal axis; application, given as a preferred example, to the realization of the femoral part of a total knee prosthesis, specifying that, in this figure, certain dimensions have been exaggerated compared to others to bring out the characteristics of this embodiment. It is first of all specified that, in the three figures, the same references designate the same elements, whatever the figure on which they appear and whatever the form of representation of these elements.

With reference to the three figures, the present invention relates to a portion of prosthesis 100 capable of being implanted on a resected end.

200 of a bone, as an example of a long bone 300 defined along a longitudinal axis 400.

The part of the prosthesis shown in the figures is, as an example of application, that of the femoral part of a total knee prosthesis which, in a known manner, adopts a U-shape, as can be seen in the three figures. In this case, the long bone 300 is a femur whose distal resected end 200 is shown in broken lines.

To implant such a part of the prosthesis, the practitioner dislocates the knee and then resects the distal end of the femur, so as to define, on this distal end of the femur, a first cylindrical surface 210 which, by mathematical definition, is generated by a generator 220 moving parallel to itself and perpendicular to the longitudinal axis 400 of the long bone 300, relying on a director, the director of this first cylindrical surface 210 having, in this case illustrated, a shape substantially U. But this director may have any other shape, rectilinear or curved, especially for other prostheses to implant on other types of bone. In Figure 2, since the trace of the first cylindrical surface

210 is in the plane of the figure, the direction of the generators is represented by the point 220 since it is substantially perpendicular to the plane of this figure.

According to a characteristic of the invention, the prosthesis portion 100 comprises a part 101, generally metallic, comprising a second substantially congruent cylindrical implantation surface 102 of the first cylindrical surface 210 of the resected end 200, and intended to be superposed. , sliding in a direction perpendicular to the longitudinal axis 400, in contact with this resected end 200.

It further comprises at least one thin rigid blade 104 integral with one 105 of its edges of the second cylindrical implantation surface 102, this thin rigid blade 104 being substantially included in a third substantially cylindrical surface generated by a generator substantially parallel to that which defines the second cylindrical implantation surface 102, so that this thin rigid blade 104 is able to penetrate transversely into the resected end 200 of the long bone 300, by a translation of the part 101 following a direction parallel to the generatrix and therefore perpendicular to the longitudinal axis 400. It is possible to previously perform in the resected end

200, a lateral cut to promote the penetration of the blade 104 into the cortex of the bone 300.

It is specified that, for a thin rigid blade, in the sense of the present description, there is included a relatively long and wide element, but having a very small thickness, not necessarily the same over its entire length, that is to say an element which, in its function, can be likened to a surface of any profile, plane or curve. Thus, in one possible embodiment, the blade may be substantially flat, such as those referenced 104, 114, 114-1 in the figures.

Advantageously, the prosthesis portion 100 according to the invention comprises at least two thin unmixed rigid blades, for example substantially aligned on the same generator as the blades 104, 114 shown in Figure 1. If they are not aligned on the same generatrix, advantageously, the two third cylindrical surfaces then form between them a non-zero angle, such as for example the two blades 104 and 114-1 in Figure 2, so that the prosthesis portion positioned on the end resected distal 200 of the bone 300 with the two blades 104 and 114-1 introduced into the cortex of the bone, is already relatively well maintained, even before the osteosynthesis produces its effect. But it is possible to obtain the result mentioned above with a single blade as the blade 124 shown in Figure 2, the third cylindrical surface is a curved surface.

It is specified that the prosthesis portion 100 may comprise the three types of blade defined above, so that FIG. 2 may be a representation of a possible embodiment of the prosthesis portion according to the invention comprising at least these three blades.

To promote the introduction of the blades 104, 114, 114-1, 124, it is advantageous that the edge 115 of these blades defined in a direction parallel to the longitudinal axis 400 of the bone 300 (or similar to this direction) and able, the first, to penetrate transversely into the resected end 200 of the bone, and more particularly in the cortex, beveled.

It is specified that each blade 104, 114, 114-1, 124 may be covered for example with cells and / or a product such as a cement or the like promoting the attachment of the prosthesis with the bone material. The present invention also relates to a method for performing the implantation of a prosthesis portion 100 comprising a part 101 comprising a cylindrical implantation surface which corresponds to the second cylindrical surface 102 defined above, on an end 200 of a bone 300 defined along a longitudinal axis 400.

This method consists essentially in resecting the end 200 of the bone according to a cylindrical receiving surface which corresponds to the first cylindrical surface 210 defined above, generated by a generatrix moving parallel to itself and perpendicular to the axis longitudinal

400 of the bone 300 so that this cylindrical receiving surface 210 is congruent with the cylindrical implantation surface 102, and positioning this prosthesis portion on the resected end 200 of the bone by translating it in a direction substantially perpendicular to the longitudinal axis 400 of the bone, so that the two congruent cylindrical surfaces of implantation and reception are superimposed.

FIG. 3 represents a part of another improved and preferred embodiment of a prosthesis part according to the invention that can be implanted on, for example, the resected end of a femur, for an application to the realization of the femoral part of a total knee prosthesis.

This embodiment is substantially identical to that described above, but has at least three additional features that allow a more secure implantation of the prosthesis portion.

One, first, of these additional features is constituted by the fact that the third surface of substantially cylindrical shape is generated by a generatrix making a slight angulation α, very advantageously less than ten degrees and which has been exaggerated in FIG. the sole purpose of clearly highlighting this structural feature, with respect to a portion 161 of the second cylindrical implantation surface 102 which is substantially parallel to the longitudinal axis 400, in order to limit the penetration of the part 101 in the resected end 200 of the bone 300. Indeed, by making this piece 101 on the resected end of the long bone penetrate as explained above, the portion of bone 160 which is located between the blade 104 and the portion 161 of the corresponding second cylindrical surface at one side of the U, after a certain translation of the blade in the bone, compress sufficiently to prevent the piece from continuing to advance, if not against a strong resistance that will attract the attention of the practitioner. It is pointed out that by "a side of the U" is meant any wall substantially parallel to the longitudinal axis 400, whatever the nature of this wall.

A second additional feature is constituted by the fact that the edge 115 of the blade 104, 114 able to penetrate first into the resected end 200 of the femur 300 is bevelled and shaped like a rostrum 150, so that there is between the edge 115 and the bottom 163 of the U-shaped part or a prosthetic tray, a quantity of bone 164 which will maintain the piece 101 in contact with the resected face of the bone on which is implanted the prosthesis portion and which is substantially perpendicular to the longitudinal axis 400 of the bone, avoiding a displacement of this part 101 in the direction of this axis 400, as long as the osteosynthesis has not produced its final effects.

Finally, the third additional characteristic is constituted by the fact that the blade 104 has a thickness, taken along a perpendicular to the generatrix, which increases substantially continuously from its edge 115 able to penetrate first into the resected end 200 of the bone 300 to the opposite edge 151 defined in a plane substantially perpendicular to the second cylindrical implantation surface 102.

With this feature, when the piece 101 has taken its final position on the resected end of the bone, it may occur osteosynthesis opposite 165 of the opposite edge 151 of the blade 104, which will prevent the piece 101 has a tendency to retreat in relation to its direction of implantation.

Thus, with these three additional features defined above taken in combination, the osteosynthesis between the prosthesis part and the bone can be performed safely for the patient, without having to fear that the prosthesis part that the Practitioner implanted it undergoes parasitic displacements.

Claims

1. A prosthesis portion (100) adapted to be implanted on a resected end (200) of a bone (300) defined along a longitudinal axis (400), this resected end being delimited by a first cylindrical surface (210) generated by a generator (220) moving parallel to itself and perpendicular to the longitudinal axis (400) of said bone (300), characterized in that it comprises:

A workpiece (101) comprising a second cylindrical implantation surface (102) congruent with said first cylindrical surface (210) of the resected end (200) and intended to be superimposed by sliding in contact with this resected end, and " at least one thin rigid blade (104) integral with one (105) of its edges of said second cylindrical implantation surface (102), said thin rigid blade (104) being substantially comprised in a third substantially cylindrical shaped surface generated by a generator substantially parallel to that which defines said second cylindrical implantation surface (102), so that said thin rigid blade (104) is able to penetrate into said resected end (200) of the log bone (300) by a translating said part (101) in a direction parallel to said generator.

2. prosthesis part according to claim 1, characterized in that said third surface of substantially cylindrical shape is substantially flat.

3. portion of prosthesis according to one of claims 1 and 2, characterized in that it comprises at least two thin rigid blades not confused (104, 114, 114-1).

4. portion of prosthesis according to claim 3, characterized in that the said two rigid thin blades (104, 114) are substantially aligned on the same generator.

5. The prosthesis portion according to one of claims 3 and 4 characterized in that the said two third cylindrical surfaces form between them a non-zero angle.

6. Prosthesis part according to claim 1, characterized in that said third cylindrical surface is a curved surface (124).

7. prosthesis part according to one of the preceding claims, characterized in that the at least one thin rigid blade (104) has a substantially flat overall shape and said third substantially cylindrical surface is generated by a generator making a slight angulation (α) with respect to a portion of the second cylindrical implantation surface (102) which is substantially parallel to the longitudinal axis (400).

8. portion of prosthesis according to one of the preceding claims, characterized in that the edge (115) of the at least one blade (104) adapted to penetrate first into the resected end (200) of said bone (300). ) is bevelled and shaped rostrum (150).

9. portion of prosthesis according to one of the preceding claims, characterized in that the at least one blade (104) has a thickness, taken along a perpendicular to said generator, which grows substantially continuously from its edge (115). adapted to penetrate first into the resected end (200) of said bone (300) to the opposite edge (151), said opposite edge being defined in a plane substantially perpendicular to the second cylindrical implantation surface (102).

10. The prosthesis portion according to one of the preceding claims, characterized in that the second cylindrical implantation surface (102) of said piece (101) has a generally U-shaped general shape.

11. A method for performing the implantation of a prosthesis portion (100) having a workpiece (101) comprising a cylindrical implantation surface (102), on an end (200) of a bone (300) defined according to a longitudinal axis (400), consisting of:

Resecting the end (200) of the bone according to a cylindrical receiving surface (210) generated by a generator moving parallel to itself and perpendicular to the longitudinal axis (400) of the bone (300) such that said cylindrical receiving surface (210) is congruent with the cylindrical implantation surface (102), and

Positioning said prosthesis portion on the resected end (200) of the bone by translating it in a direction substantially perpendicular to the longitudinal axis (400) of the bone, so that the two congruent cylindrical implantation surfaces and reception overlap.