WO2001056507A1

WO2001056507A1 - Device for fixing an implant or transplant forming a prosthetic ligament on a bone

Info

Publication number: WO2001056507A1
Application number: PCT/FR2001/000346
Authority: WO
Inventors: Jacques Afriat; Gérard Fonfreide
Original assignee: Dedienne Sante
Priority date: 2000-02-07
Filing date: 2001-02-06
Publication date: 2001-08-09
Also published as: FR2804598A1; FR2804598B1; AU2001235614A1

Abstract

The invention concerns an implant or transplant (3) engaged in a tunnel (8) and provided with strands (6) enabling it to be fixed. The invention is characterised in that the device (10) comprises: a base component (11) whereof the distal portion (16) has a cavity (17) and a plurality of ducts (18), each of said ducts (18) being adapted to receive one of said strands (6); a locking component (12), configured to be engaged in said cavity (17) and to take up an unclamping position, wherein it allows the strands (6) to slide between it and the base component (11), and a clamping position wherein it clamps said strands (6) so as to prevent any sliding of said strands (6), and means (13, 19, 27) for moving said locking component (12) between clamping and unclamping positions.

Description

DEVICE FOR FIXING AN IMPLANT OR TRANSPLANT FORMING A PROSTHETIC LIGAMENT ON A BONE

The present invention relates to a device for fixing to an bone an implant or a transplant forming a ligament. This device is particularly intended for fixing on the tibia of an implant or a transplant to replace the anterior cruciate ligament of the knee joint.

The knee ligamentoplasty techniques most often use a ligament or tendon transplant taken from the knee to be treated. Synthetic transplants have indeed been neglected for a few years due to a high rupture rate in the medium term. Two techniques are currently used. The so-called "KENNETH-JONES" technique consists in removing a portion of the patellar tendon as well as the portions of patellar and tibial bone on which the ends of the tendon fibers are inserted. These bone portions constitute grafts which are engaged in bone tunnels arranged in the femur and in the tibia, and are fixed to these bones by means of headless screws called "interference screws".

The technique called "internal semi-tendon law", or "DI-DT", consists of removing one or two tendons from the crow's feet (internal right-semi-tendon). This or these tendons are then folded back on themselves at their median part to constitute a ligament transplant with two or four bundles.

The fixation of these beams can be ensured, at the level of the tibial tunnel, by an interference screw.

The use of such a screw however involves several drawbacks. Indeed, the screw can deteriorate the beams during its installation, its thread coming to bite into these beams. In addition, the tensioning of the transplant is not completely controlled since the screw can carry this transplant with it during its positioning, which influences the tension of the latter.

In addition, the use of an interference screw is impossible when the transplant is too short, the length of the tibial tunnel can then exceed from 33 to 40 mm the length of the transplant. It is not always possible to have a transplant of sufficient length to reach the proximal orifice of the tibial tunnel. Another fixing means consists in placing a lacing on the end of each bundle of the transplant, or of each pair of bundles, which is opposite to said middle fold. Each of these lacings ends, for each bundle or pair of bundles, by two strands which can be used to pull the bundles into the tibial tunnel and to fix these bundles to the bone.

According to a fixing technique used in this case, the strands are placed against the wall of the tibia and are fixed to the latter by means of a screw with washer or by means of a staple. However, this technique is criticized for presenting a risk of shearing of the strands on the edge of the bone tunnel, which is relatively sharp.

According to another fixing technique used in the same case, a washer with a diameter greater than the diameter of the tunnel is used, having holes for the passage of the strands through it and comprising a circular wall projecting from one of its sides, the outside diameter of which is less than the diameter of the tibial tunnel. The strands are engaged through the holes of the washer and said circular wall is engaged in the proximal opening of the tunnel, after which the strands are placed in adequate tension and are knotted on the proximal face of the washer.

This washer has several drawbacks. Indeed, said circular wall has a length insufficient to allow a solid wedging of the washer with respect to the tibial tunnel, and has an axis perpendicular to the plane of the washer, while the tibial tunnel has an oblique orientation of approximately 45 ° by compared to the cortical area into which it leads. As a result, this washer is not perfectly maintained relative to the bone, which can be detrimental to the sustainability of the anchoring carried out.

In addition, it is difficult to perfectly adjust the tension of the transplant, which depends on the making of knots, and it is impossible to change the tension of the transplant once the strands have been tied.

The present invention aims to remedy these important drawbacks.

To this end, the system it concerns includes:

a base part having a distal body capable of being engaged in the bone tunnel and a clean proximal flange bearing against the bone wall when said body is engaged in the tunnel, in order to axially block this body in this tunnel; the body has a cavity opening into its proximal face and a plurality of conduits opening into this cavity on the one hand and into the distal face of the body on the other hand, each of these conduits being suitable for receiving one of said strands and for allow sliding of this strand in it;

- A blocking part, shaped to be able to be engaged in said cavity and to occupy two axial positions in this cavity, namely a loosening position relative to the base part, in which this blocking part allows passage and sliding strands between it and the wall of the base part delimiting said cavity, and a clamping position relative to the base part, in which it clamps said strands so as to block any sliding of these strands, and

- Means for moving said blocking piece relative to the base piece between said clamping and loosening positions, and to maintain this blocking piece in the clamping position relative to the base piece.

The strands can thus be engaged through the conduits of the body, starting from the distal face thereof, until opening into the cavity of the base part and beyond the proximal face thereof, then the part base can be placed on the bone, by engagement of said body in the bone tunnel and coming from the collar against the bone wall. The blocking piece is then placed on the base piece and the strands are put in adequate tension. The blocking part is then brought into the clamping position relative to the base part to immobilize these strands relative to the device.

These base piece and blocking piece thus make it possible to immobilize the strands without making knots, which eliminates the drawbacks of these knots, such as the difficulty of controlling the tension of the strands, the risk of loosening the knots or the discomfort caused to the patient by the volume of the nodes.

In addition, the strands remain oriented substantially in the longitudinal direction of the transplant and are therefore not bent at right angles as in the prior art, which allows them to undergo tension / loosening cycles under optimal conditions and to eliminate all rubbing against a surface likely to cause wear. In addition, the tension of the strands can be easily corrected by simply loosening the locking piece.

The device therefore has the advantage of having a small footprint, allowing easy locking of the strands and a solid hold thereof.

Preferably, the collar is shaped so as to extend in a plane which forms, with respect to the axis of the body, an angle corresponding to the angle formed by the axis of the bone tunnel with the face in which this tunnel opens. The orientation of this collar relative to the body thus corresponds to that of the tunnel relative to said face, so that this collar presses against said face and ensures perfect axial immobilization of the base part relative to the bone.

Preferably, the wall of the base part delimiting said cavity and / or the side wall of the blocking part has (s) a plurality of grooves, each of which is arranged in the extension of one of said conduits.

In the loosening position of the blocking piece, these grooves allow each strand to be guided and the different strands to be properly separated; in the clamping position of this same part, these grooves allow the strands to be clamped without excessive crushing thereof.

When only the blocking part comprises such grooves, the base part and the blocking part comprise means for angular positioning of the blocking part relative to the base part in a position in which said grooves are placed opposite said ducts.

According to a simple embodiment of the invention, said clamping means consist of a tapped hole arranged axially in the base part, by a hole formed in the blocking part, coming coaxially to the tapped hole when the blocking part is placement on the base part, and by a screw whose threaded body can be engaged in these holes and whose head can bear against the base part.

Anti-rotation means of the blocking part relative to the base part when tightening or loosening of this screw can then be provided. These means can be the same as the above-mentioned angular positioning means.

The blocking piece may also have a surface appearance capable of increasing its capacity for blocking the strands, in particular streaks, ribs, grooves or other roughness.

For a good understanding, the invention is again described below with reference to the appended diagrammatic drawing representing, by way of nonlimiting example, a preferred embodiment of the device which it concerns. Figure 1 is a simplified view of a tibia, a femur, an implant forming a prosthetic anterior cruciate ligament, and this device before fixing the implant to the tibia; Figure 2 is a side view of the device, on an enlarged scale, in section passing through its axis; Figure 3 is an end view of one of the parts that includes this device; Figure 4 is an end view of another part that includes this device; FIG. 5 is a view of the device similar to FIG. 2, after placement on the tibia, in a loosening position allowing the tension of the ligament implant to be adjusted, and FIG. 6 is a view of the device similar to Figure 5, in a clamping position allowing the attachment of the ligament implant to the tibia. Figure 1 shows the tibia 1 and the femur 2 of a knee joint whose anterior cruciate ligament has been ruptured or removed. This ligament must be replaced by a ligament transplant 3, according to the technique known as "internal right-semi-tendon", or "DI-DT".

This technique consists of removing one or two tendons from the crow's feet (internal right-semi-tendon). This or these tendons are folded back on themselves at their median part to constitute the transplant 3, the latter being able to have two or four bundles, then a lacing 4 is placed on the end of each bundle, or of each pair of beams, which is opposite to the middle fold 5. Each of these lacings 4 ends, for each beam or pair of beams, by two strands 6. As shown in the figures, part 3a of the transplant 3 ending in the fold 5 is engaged through a tunnel 7 arranged in the femur 2. This part 3a is fixed to the femur 2 by appropriate means, not shown because not forming part of the invention. The part 3b of the transplant 3 ending in the lacings 4 is engaged in a tunnel 8 arranged in the tibia 1. It can be pulled into this tunnel 8 by means of the strands 6 and can be fixed to the tibia 1 thanks to these and to the device 10.

The latter is more particularly visible in FIGS. 2 to 5. It comprises a base part 1 1, a blocking part 1 2 and a screw 13.

The base part 1 1 has a proximal collar 1 5 and a distal body 1 6, this collar 1 5 and this body 1 6 being integral with one another. This part 1 1 can in particular be metal such as stainless steel or titanium.

The collar 1 5 extends in a plane which forms, with respect to the axis of the body 1 6, an angle of about 45 °, that is to say an angle corresponding substantially to the angle that usually forms the axis of the tunnel 8 with the bone face into which this tunnel 8 opens.

The body 1 6 is substantially cylindrical and is dimensioned so that it can be closely engaged in the tunnel 8.

It has a cavity 1 7 opening into its proximal face, four conduits 1 8 opening into this cavity 1 7 on the one hand and into the distal face of the body 1 6 on the other hand, and a tapped hole 1 9 arranged axially.

The bottom of the cavity 1 7 is substantially hemispherical, with the exception of a boss 20 projecting radially inward from this cavity 1 7.

Each of the conduits 18 is suitable for receiving one of the strands 6 and allowing this strand 6 to slide in it.

The blocking piece 1 2 has a generally hemispherical shape, and is shaped to be able to be engaged in the cavity 1 7. This piece 1 2 can be made of polyethylene or metallic material, in particular stainless steel or titanium. It has four grooves 25 arranged from its peripheral face, and a housing 26 shaped to be engaged on the boss 20.

These grooves 25 and housing 26 are respectively positioned so that each of the grooves 25 comes opposite the orifice of one of the conduits 1 8 when the blocking piece 1 2 is placed in the cavity 1 7 and that the housing 26 is engaged on the boss

20.

The locking piece 12 further comprises a hole 27 arranged in it axially. This hole 27 is positioned coaxially with the hole 19 when the blocking piece 12 is placed on the base piece 11.

This part 1 2 also has ribs 28 capable of increasing its capacity for blocking the strands 6.

The screw 1 3 has a body 30 capable of being engaged through the hole 27 and of being screwed into the hole 1 9, is a head 31 capable of bearing against the proximal face of the part 1 2.

As shown in Figures 5 and 6, the device 10 is shaped so that, in a loosening position of the screw 13 shown in Figure 5, the blocking piece 1 2 allows the passage and sliding of the strands 6 between it, at its grooves 25, and the wall of the base part 1 1 delimiting the cavity 1 7. In a tightening position of this same screw 1 3, shown in Figure 6, the part 1 2 tightens said strands 6 between it, at its grooves 25, and the wall of the base part 1 1 so as to block any sliding of these strands 6. In practice, the two or four strands 6 are engaged in the conduits 18 then the base part 1 1 is placed in the opening of the tunnel 8, by impaction. The collar 1 5, by its orientation, comes to bear against the bone wall 40 delimiting the proximal opening of this tunnel 8. The part 1 2 is then engaged in the cavity 1 7, the strands 6 being engaged in the corresponding grooves 25 .

Adequate traction is then exerted on the strands 6 then the screw 1 3 is put in place and tightened until the strands 6 are immobilized relative to the device 10. During this tightening, the boss 20 makes it possible not only to position the grooves 25 opposite the orifices of the conduits 18 but also to block the blocking piece 1 2 in rotation to prevent the tightening of the screw 13 driving the piece 1 2 in rotation.

It appears from the above that the invention provides a device for fixing an implant or a ligament transplant on a bone having numerous advantages compared to homologous devices of the prior art. This device can indeed be perfectly wedged with respect to the tibial tunnel, allows to perfectly adjust the tension of the transplant, without making knots, and if necessary allows to modify the tension of the implant or transplant. It goes without saying that the invention is not limited to the embodiment described above by way of example but that, on the contrary, it embraces all of the variant embodiments thereof. Thus, the body 1 6 may have a frustoconical shape and a section which decreases in the distal direction, to allow a wedging of this body in the bone tunnel.

Claims

1 - Device (10) for fixing an implant or a ligament transplant (3) on a bone, this implant (3) being engaged in a tunnel (8) arranged in the bone (1) to receive it and being provided with strands (6) connected to it to allow its attachment to this bone (1); device (10) characterized in that it comprises:

- A base part (11) having a distal body (16) capable of being engaged in the bone tunnel (8) and a proximal collar (15) capable of coming to bear against the bone wall (40) when said body (16 ) is engaged in the tunnel (8), in order to axially block this body (16) in this tunnel (8); the body (16) has a cavity (17) opening into its proximal face and a plurality of conduits (18) opening into this cavity (17) on the one hand and into the distal face of the body (16) on the other hand, each of these conduits (18) being adapted to receive one of said strands (6) and to allow this strand to slide in it;

a blocking part (12), shaped to be able to be engaged in said cavity (17) and to occupy two axial positions in this cavity (17), namely a loosening position relative to the base part (11), wherein this blocking piece (12) allows the passage and sliding of the strands (6) between it and the wall of the base piece (11) delimiting said cavity (17), and a clamping position relative to the piece base (11), in which it clamps said strands (6) so as to block any sliding of these strands (6), and -means (13, 19, 27) making it possible to move said blocking piece (12) by relative to the base part (11) between said clamping and loosening positions, and to maintain this blocking part (12) in the clamping position relative to the base part (11).

2 - Device (10) according to claim 1, characterized in that the collar (15) is shaped so as to extend in a plane which forms, with respect to the axis of the body (16), an angle corresponding to the angle formed by the axis of the bone tunnel (8) with the face (40) into which this tunnel (8) opens.

3 - Device (10) according to claim 1 or claim 2, characterized in that the wall of the base part (11) delimiting said cavity (17) and / or the side wall of the blocking part (12) has (nt) a plurality of grooves (25), each of which is arranged in the extension of one of said conduits (18).

4 - Device (10) according to claim 3, characterized in that only the blocking part (1 2) comprises said grooves (25), and in that the base part (1 1) and the blocking part (1 2) comprise means (20, 26) for angular positioning of the locking piece (12) relative to the base piece (1 1) in a position in which said grooves (25) are placed opposite said conduits (18 ).

5 - Device (10) according to one of claims 1 to 4, characterized in that said clamping means consist of a threaded hole (19) arranged axially in the base part (1 1), by a hole (27 ) fitted in the blocking part (1 2), coming coaxially to the threaded hole (19) when the blocking part (1 2) is placed on the base part (1 1), and by a screw (1 3 ) whose threaded body (30) can be engaged in these holes (27, 19) and whose head (31) can bear against the base part (1 1).

6 - Device (10) according to claim 5, characterized in that it comprises means (20, 26) anti-rotation of the locking piece (1 2) relative to the base piece (1 1) during tightening or loosening of said screw (13).

7 - Device (10) according to claim 6, characterized in that said anti-rotation means are the same as said angular positioning means.

8 - Device (10) according to one of claims 1 to 7, characterized in that the bottom of the cavity (1 7) is substantially hemispherical, and in that the blocking piece (1 2) has a general hemispherical shape .

9 - Device (10) according to one of claims 1 to 8, characterized in that the body (1 6) has a frustoconical shape and a section which decreases in the distal direction, to allow jamming of this body (1 6) in the bone tunnel.

10 - Device (10) according to one of claims 1 to 9, characterized in that the blocking part has a surface appearance capable of increasing its blocking capacity strands, in particular, streaks, ribs, grooves or other roughness .