WO1996000538A1

WO1996000538A1 - Prosthetic knee joint, particularly a single-compartment knee prosthesis or a kneecap prosthesis

Info

Publication number: WO1996000538A1
Application number: PCT/FR1995/000881
Authority: WO
Inventors: Vincent Chassaing; François COMBELLES; Gérard YSEBAERT; Benoit Droillard; Franck Herrault
Original assignee: Ysebaert S.A.
Priority date: 1994-06-30
Filing date: 1995-06-30
Publication date: 1996-01-11
Also published as: FR2721820B1; FR2721820A1

Abstract

A prosthetic joint, particularly a knee or kneecap prosthesis, wherein a fixed component (1) has a recess (2) engageable by a portion projecting from the bearing surface of an intermediate component so that the intermediate component can move sideways and crosswise and rotate in a plurality of ways relative to the first component, said intermediate component being rotated about axes that are substantially perpendicular to the first bearing surface.

Description

Prosthetic knee joint, in particular unicompartmental knee prosthesis, or patella prosthesis.

The present invention relates to a prosthetic joint. of the knee, in particular a single-behavior knee prosthesis, or a kneecap prosthesis.

Such prostheses are used to replace, during a surgical operation, natural cartilages presenting deficiencies due to an illness or a trauma.

Several prostheses with mobile meniscus are known in the prior art. The prosthesis called "OXFORD" described for example in French patent n ° 2290883 comprises a tibial platform having a flat surface on which an intermediate piece is movable in translation. A mushroom-shaped projecting part, cooperating with a cavity provided in the lower part of the intermediate piece, makes it possible to limit the displacement relative to the tibial platform. Such a prosthesis is not entirely satisfactory, due to the excessive stresses undergone by the intermediate piece, usually made of plastic. In fact, the edges of the cavity, of section greater than the section of the mushroom-shaped projecting part extending to the upper surface of the tibial platform, strike said projecting part. Due to the significant forces exerted on a knee prosthesis, these repeated shocks lead to rapid deterioration of the intermediate piece. To avoid such deterioration, European patent n ° 0021.421 describes a prosthesis whose tibial platform has two curved guide grooves cooperating with the lower surface of two movable menisci having a projecting part whose section is in the shape of a tail dovetails. This prosthesis marketed under the name LCS, is intended for the surgical replacement of a functionally injured knee and allows to faithfully reproduce the different degrees of freedom of the knee joint, and to improve the comfort of the patient equipped with such a prosthesis. .

These prostheses have the disadvantage of a small bearing surface of the menisci on the tibial platform. The significant efforts, which can reach ten times the weight of the person on whom the prosthesis was implanted, are distributed over a small area and therefore lead to a deterioration of the menisci.

English patent 1534263 describes another prosthesis comprising a linear guide groove allowing a forced displacement of an intermediate piece.

Another document of the prior art, French patent FR2685632 describes a prosthetic assembly comprising:

- A first type of femoral element able to cooperate either with a movable plate of a tibial base to constitute a knee prosthesis with a movable plate, or with a fixed plate of a tibial base to constitute a knee prosthesis with a fixed plate with conservation of the posterior cruciate ligaments.

- A second type of femoral element capable of cooperating with a fixed plate of the tibial base, to constitute a posterior stabilized knee prosthesis with fixed plate.

Another French patent FR2692476 describes a total knee prosthesis of the sliding type, comprising a femoral element whose condylar pads cooperate in abutment on a plate of a tibial element. The tibial and femoral elements present in combination, complementary means of. adjustable utility and guidance and removable, capable of ensuring the stabilization of the two elements while respecting the ligament isometry when the anterior ligament or the two cruciate ligaments are destroyed. . We also know the French patent

FR2665073. This document discloses a total knee prosthesis of the sliding type, comprising a bi-condylar femoral part whose profiled external face comes into contact, support and centering on an intermediate element of high-density polyethylene, said intermediate element being positioned and fixed on the upper face forming a metal base of the tibial element, and in that the upper part of the tibial part is arranged with a plurality of positioning openings relative to the intermediate part, the latter comprising two centering pads for s' engage in positioning openings thus allowing adjustment in position of the intermediate plate relative to the tibial element.

European patent EP183670 describes an artificial meniscus-tibia joint for a knee joint prosthesis comprising at least one tibial component on which the meniscus is arranged so that it can move or be mobile. The meniscus has a largely planar sliding surface against the tibial component, the meniscus or the tibial component having directional control members giving the meniscus the ability to move in all directions along the tibial component, but these members direction control elements being also arranged so as to limit the amplitude of the movement.

Another patent published under the number EP519872 also relates to a semi-constrained prosthesis. It relates to a joint prosthesis, in particular of the knee. This prosthesis also has rails ensuring guiding with very little lateral clearance possible, and only minimal rotation, of the intermediate piece. These different prostheses of the prior art, however, all have constrained displacements, the comfort of which is not entirely satisfactory for the person thus fitted. • The object of the invention is to remedy this drawback by proposing a prosthesis allowing an additional degree of freedom, and thus making it possible to avoid blocking of the joint during certain movements of the knee. Another object of the invention, in one of its variant embodiments, and to propose a modular articulation allowing the surgeon to decide at any time during the intervention to place a knee joint with a movable component, or rather a fixed component joint. To this end, the invention relates more particularly to a prosthetic joint, in particular a knee prosthesis or a patella prosthesis, of the type comprising:

a) at least a first component, for example a tibial component having a first bearing surface,

- b) at least one intermediate component, for example an intermediate component having a second bearing surface, which comes into sliding contact with the first bearing surface of the first component to undergo a sliding movement relative to the latter during the movement of the joint, the intermediate component having a third bearing surface, c) a third component, in particular a femoral component having a fourth bearing surface which comes into congruent contact by sliding with the third bearing surface of the intermediate component, characterized in that at least one of the surfaces of the first component has a cavity suitable for cooperating with a part projecting relative to the second bearing surface of the intermediate component so as to allow lateral movements, movements transverse and a plurality of rotational movements of the intermediate component with respect to the first component, the rotational movements taking place along axes substantially perpendicular to the first bearing surface. Preferably, the cavity is delimited by a convex outer edge and a substantially straight internal edge.

According to a preferred embodiment, the cavity has a flat bottom, and a projecting convex external edge and a substantially internal edge, the section of the cavity being greater than the section of the projecting part of the intermediate component.

Advantageously, the cavity has a lateral opening for the introduction of the heel of the intermediate component.

According to an alternative embodiment, the cavity has an enlarged part for the vertical introduction of the heel of the intermediate component.

According to a particular embodiment, the part projecting from the lower surface of the intermediate part is of cylindrical shape.

According to a variant, the projecting part accommodating in the complementary cavity has a diameter substantially equal to the largest section measured perpendicular to the internal edge substantially.

According to another variant, the part forming a projection with respect to the lower surface of the intermediate part has a section formed by two arcs of circles tangentially connecting, and by two segments substantially forming a convex triangular part.

According to a second embodiment, the projecting part is symmetrical with respect to an anteroposterior axis. The invention relates in one of its forms to a knee prosthesis the first component of which is a tibial component, the intermediate component is a meniscal component and the third component is a femoral component and in that the tibial component is adapted to receive in the alternative a meniscal component having a heel whose section corresponds substantially to the section of the cavity prevent lateral and rotational movements. This embodiment constitutes the variant of prosthesis with fixed meniscus making it possible to adapt the same tibial plateau and the same femoral component to a situation appearing during surgery, in which the ligaments are more degraded than initially anticipated.

According to a variant of the two-compartment type, the plate of the first component has on each of its condylar parts a cavity (2), each of the cavities cooperating with a part projecting from the second bearing surface of the corresponding intermediate component so as to allow lateral movements, transverse movements and rotational movements of each of the meniscus components (2) relative to the tibial component, the rotational movements being carried out along an axis substantially perpendicular to the first bearing surface and offset laterally by compared to the shin.

The invention relates in another embodiment to a movable ball joint.

The invention will be better understood on reading the description which follows, referring to the accompanying drawings in which:

- Figure 1 top view of the tibial component with the lower parts of the meniscal parts;

- Figure 2 shows a view of the tibial component and the meniscal component along a section plane BB ';

- Figure 3 top view of the tibial component and the meniscal component, according to two alternative embodiments; - Figures 4 to 7 show the movements of the meniscal component relative to the tibial component;

- Figure 8 shows a view of the tibial component and the meniscal component according to an alternative embodiment.

- Figure 9 shows a view of a prosthesis of the patella.

Figure 1 shows a top view of the tibial component in a preferred unicompartmental embodiment. The upper surface of the tibial component has an oblong cavity (2) in which the lower part (4) of a meniscal component is housed. The tibial component (1) is fixed to the tibia in a known manner by one or more grooved tips or covered with a biocompatible material intended to penetrate into the spongy tissue. The dimensions of the tibial component are within a rectangle of approximately 48 x 29 millimeters.

The cavity (3) is symmetrical, in the example described, with respect to the interior-exterior median plane BB '. In the first variant described, the cavity has a rounded outer edge (8) extending over approximately 180 degrees, and having a radius of curvature of 24 millimeters. The two ends of this rounded edge (8) are connected by a substantially edge (9) extending parallel to the anteroposterior axis AA '.

The meniscal part has at its lower part a heel (11) having two parts of different sections. In the first exemplary embodiment, the heel is of cylindrical shape. The lower part (29) has a diameter slightly less than the largest section of the cavity (2), so as to preserve a slight lateral movement along the internal-external axis BB ', and to allow an anteroposterior displacement according to the direction AA 'of the meniscal parts, in association or not with a rotational movement on itself or with respect to eccentric axes of rotation, internal or external. This the lower part (29) is surmounted by an intermediate part (32) having a smaller section than the section of the lower part (29). The section of the lower part (29) is however greater than the section of the opening of the cavity to prevent the unexpected withdrawal of the meniscal component.

The bottom of the cavity (2) is flat. The edge of the cavity (2) has a widening (30) allowing the vertical introduction of the meniscal heel into one of the extreme positions of the meniscal component.

2 shows a partial sectional view of the tibial plateau (1) provided with a meniscal component (12).

The cavity (3) is bordered by a rim (13, 14) delimiting an opening having the same shape as the bottom (15) of the cavity, but of slightly smaller section.

The projecting part (4) of the meniscal part has an annular peripheral groove (16) coming to cooperate with the rim (13, 14) in order to prevent the unexpected withdrawal of the meniscal part. The height of the groove corresponds to the thickness of the lower part (29) of the meniscal heel. The thickness of the rim (13, 14) corresponds substantially to the height of the intermediate part (32). Figure 3 shows a top view of the tibial plateau according to two embodiments.

On the left, the cavity opens by a passage (18) allowing the positioning of the meniscal component in an anteroposterior direction. On the left, the cavity opens towards the center of the plate by an opening (19) allowing the introduction by a transverse displacement.

Figures 4 to 7 show different possible positions of the meniscal component relative to the tibial plateau. In FIG. 4, the meniscus occupies a central position, and the directing axes (20, 21) of the meniscal component (22) are aligned with the directing axes (23, 24) of the tibial plateau. In FIG. 5, the meniscal component (22) is shown with a normal orientation, the anteroposterior axis of the meniscal component (22) being parallel to the anteroposterior axis of the tibial plateau, the meniscal component having undergone a slight anteroposterior offset. In FIG. 6, the meniscal component (22) is moved to the anterior position and has undergone a slight pivoting relative to an external axis 0.

In FIG. 7, the meniscal component (22) is moved to the anterior position and has undergone a slight pivoting with respect to an internal axis 0 '.

FIG. 8 represents an alternative embodiment according to which the heel of the meniscal component is no longer cylindrical, but of polygonal shape.

The heel section has an external face made up of two arcs of circles (24, 25) which join in a tangent manner. On the internal side, the heel is delimited by two substantially segments (26, 27).

In the same way as in the variant with a cylindrical heel, the meniscal component has a peripheral groove which comes to cooperate with a rim surrounding the cavity (2) of the tibial component to prevent the unexpected withdrawal of the meniscal component.

FIG. 9 represents a joint according to the invention forming a prosthesis for the patella. It consists of a first patellar component (40) having a cavity (42) of cross section greater than the cross section of the heel (43) of the movable component (44).

The movable component (44) has a congruent upper surface (45). Known knee prostheses are round and symmetrical. They pose significant problems due to friction. The purpose of the patella prosthesis is to reduce friction by using a mobile component having a freedom of movement in translation and in rotation, of a limited amplitude, relative to the fixed part, and to present a congruent sliding surface.

The movable component (44) can move in translation and in rotation inside the cavity (42) of the first component (40).

It goes without saying that numerous modifications can be made to the prosthesis described and shown by way of nonlimiting example without departing from the scope of the invention.

Claims

1 - Prosthetic joint, in particular knee prosthesis or patella prosthesis, of the type comprising: - - a) at least one first component, for example a tibial component (1) having a first bearing surface,

- b) at least one intermediate component, e.g. intermédiai re component (22) pos sédant ^a second bearing surface, which comes into cont act by gli ng with the first bearing surface of the first component (1) for undergo a sliding movement relative to the latter during the movement of the joint, the intermediate component (22) having a third bearing surface, c) a third component, in particular a femoral component having a fourth bearing surface which comes into congruent contact by sliding with the third bearing surface of the intermediate component (22), characterized in that at least one of the surfaces of the first component

(1) has a cavity (2) suitable for cooperating with a protruding part of the intermediate component so as to allow lateral movements, transverse movements and a plurality of rotational movements of the intermediate component relative to the first component, the rotational movements taking place along axes substantially perpendicular to the first bearing surface.

2 - Prosthetic knee joint according to claim 1, characterized in that the cavity (2) has a convex outer edge and a substantially straight inner edge.

3 - prosthetic knee joint according to claim 1 or 2, characterized in that the cavity (2) has a flat bottom, and a projecting convex external edge and a substantially internal edge, the section of the cavity (2) being greater than the section of the projecting part of the intermediate component.

4 - Prosthetic knee joint according to any one of the preceding claims, characterized in that the cavity (2) has a lateral opening for the introduction of the heel of the intermediate component.

5 - Prosthetic knee joint according to claim 3 and 4, characterized in that the cavity (2) has an enlarged portion (30) for the vertical introduction of the heel of the intermediate component.

6 - Prosthetic knee joint according to any one of the preceding claims, characterized in that the part projecting from the lower surface of the intermediate part is of cylindrical shape.

7 - Prosthetic knee joint according to claim 4 and 5, characterized in that the projecting part accommodating in the complementary cavity has a diameter substantially equal to the largest section measured perpendicular to the internal edge substantially.

8 - prosthetic knee joint according to any one of claims 1 to 5, characterized in that the part projecting from the lower surface of the intermediate part has a section formed by two arcs of circles tangentially connected, and by two substantially segments form a convex triangular part. 9 - Prosthetic knee joint according to claim 8, characterized in that the protruding part is symmetrical with respect to an anteroposterior axis.

10 - Prosthetic articulation of the knee according to one that the conch of the preceding claims is characterized in that the first component is a tibial component, the intermediate component is a meniscal component and the third component is a femoral component and in that that the tibial component is adapted to receive in the alternative a meniscal component having a heel whose section corresponds substantially to the section of the cavity to prevent lateral movements.

11 - Prosthetic knee joint according to claim 9 characterized in that the plate of the first component has on each of its condylar parts a cavity (2), each of the cavities (2) cooperating with a part forming a projection relative to the second surface supporting the corresponding intermediate component so as to allow lateral movements, transverse movements and rotational movements of each of the meniscal components (2) relative to the tibial component, the rotational movements being carried out along an axis substantially perpendicular to the first bearing surface and offset laterally with respect to the tibia.

12 - Prosthetic knee joint according to any one of claims 1 to 10, characterized in that it forms a movable ball joint.