Medical-grade anchor designed for insertion into a bone wall

Description

[0001] The present invention relates to a medical anchor intended to be inserted into a bone wall.

[0002] This anchor allows one or more suture threads to be fixed to a bone in order, in particular, to reinsert a tendon or ligament onto a bone; it is particularly intended to allow the reinsertion, on a humerus, of one or more of the tendons of the rotator cuff of the shoulder joint.

[0003] A medical anchor is known from FR2682867 A1.

[0004] It is well known, in various indications, to reattach a tendon or ligament to a bone by means of an anchor inserted into the wall of that bone, this anchor being connected to one or more suture threads which allow the tendon or ligament to be sutured to the bone.

[0005] To connect the suture thread to an anchor, a common method is to create a transverse passage through the anchor, through which the suture thread is inserted. However, this type of assembly has the disadvantage of causing damage to the thread during anchor placement, due to friction between the anchor and the bone. This damage can lead to suture breakage.

[0006] It is also known to incorporate a proximal ring on an anchor, to which the suture thread is tied. This type of anchor presents a significant risk of thread breakage at the knot.

[0007] To remedy this drawback, so-called anchors were designed "knotless", in which the line is held on the anchor by pinching or wedging. Existing anchors, however, do not eliminate all risk of damage to the line during anchor installation, particularly when the anchor is screwed in, or the risk of the line being cut at its point of attachment to the anchor.

[0008] The present invention aims to remedy this major drawback.

[0009] Furthermore, a number of existing anchors exhibit relatively uncertain pull-out resistance. This problem arises particularly for anchors intended for the reinsertion of rotator cuff tendons in a shoulder joint, given the significant tension exerted on the suture thread(s), and therefore on the anchor(s), by these tendons during joint movement.

[0010] The present invention also aims to remedy this drawback.

[0011] The main objective of the invention is therefore to provide an anchor to which one or more suture threads can be perfectly fixed and retained, with a reduced risk of shearing or breakage of this or these threads.

[0012] Another objective of the invention is to provide an anchor suitable for being perfectly fixed to a bone wall.

[0013] The anchor in question comprises, in a manner known per se, two parts intended to be assembled together, namely an outer part, intended to be fixed to the bone, which forms an internal longitudinal cavity through it, and an inner part, intended to be inserted and retained in said cavity of the outer part, which forms a transverse conduit through it; at least one suture thread is intended to be engaged in said cavity through the proximal side of the outer part, to be engaged through said transverse conduit and to exit from said outer part, through said proximal side.

[0014] According to the invention, which is defined by claim 1, the outer piece forms at least a first wedging surface disposed in the longitudinal direction of the outer piece and the inner piece forms at least a second wedging surface located on the proximal side with respect to the transverse conduit which it comprises, this second wedging surface being disposed in the longitudinal direction of the inner piece; said at least one suture thread is intended to extend along said first wedging surface and along said second wedging surface;the inner part is mobile relative to the outer part between a distal position of non-blocking of the suture thread, in which said second clamping surface is at a distance from said first clamping surface that does not cause any clamping of this thread, and a proximal position of blocking of the suture thread, in which said second clamping surface is at a distance from said first clamping surface that causes a clamping of this thread.

[0015] It will be understood that the terms "proximal" and "distal" used above and throughout this description are to be considered, in a classical way, in relation to the direction of insertion of the anchor in a bone wall, the term "proximal" designating a location closer to a practitioner in relation to this direction of insertion and "distal" designating a location further away from this practitioner in relation to this same direction of insertion.

[0016] The invention provides an anchor in which the strands of the suture thread(s) are located inside the anchor during placement and are thus protected from damage that would otherwise occur between the walls of the anchor and the bone during this placement. The outer part may then include an external structure allowing for reinforced anchoring to the bone; this may consist of anchoring ribs having a significant height, and / or a non-circular cross-section of the outer part, in particular oblong, such that the outer part is able, in a first angular position, to be engaged in a receiving hole made in the bone, and then to be forcefully pivoted in this hole to another angular position, offset by approximately ninety degrees from said first angular position, so as to wedge the anchor in the hole.

[0017] Before the anchor is in place, the inner piece may not be assembled to the outer piece, allowing each suture thread to be easily engaged on the anchor.

[0018] Once the anchor is in place on the bone, traction exerted on the strands of the suture thread(s) allows the inner piece to be moved relative to the outer piece towards the said proximal blocking position, achieving a blockage of this or these thread(s) by wedging between the said first and second wedging surfaces.

[0019] These longitudinally arranged clamping surfaces allow pressure to be exerted on a relatively large portion of the wire(s), ensuring perfect clamping of the wire(s), without risk of shearing.

[0020] According to the invention, said outer part comprises two said first wedging surfaces, diametrically opposed, and said inner part comprises two said corresponding second wedging surfaces.

[0021] Thus the two strands of each suture thread are wedged in the anchor by two pairs of wedge surfaces, one located before the passage of the thread(s) through said transverse conduit, and the other located after this passage.

[0022] At least one of the said first and second wedging surfaces is inclined with respect to the longitudinal axis of the anchor.

[0023] The jamming of the suture thread(s) is thus achieved by progressive reduction, during the movement of said inner piece towards said proximal jamming position, of the space existing between said first and second jamming surfaces.

[0024] Preferably, said outer part forms at least one first engagement surface, distinct from said first wedging surface, and said inner part forms at least one second engagement surface, distinct from said second wedging surface, these respective engagement surfaces coming into mutual engagement in said proximal blocking position and achieving immobilization of said inner part relative to said outer part in this position.

[0025] The risk of the said inner part returning to the said distal non-blocking position is thus eliminated.

[0026] Preferably, these first and second engagement surfaces are inclined relative to the longitudinal axis of the anchor so as to be able to come, when the inner piece is moved in the proximal direction inside the outer piece, into a state of mutual wedging which determines said proximal blocking position, and said respective wedging surfaces are arranged in such a way that there exists between them, in this proximal blocking position, a space whose thickness is on the order of 10 to 40% of the diameter of a suture thread.

[0027] The engagement surfaces are thus arranged so that their mutual wedging occurs before said respective wedging surfaces cause excessive compression of the suture thread(s). The risk of such excessive compression is thereby eliminated.

[0028] According to a preferred embodiment of the invention, said outer part and said inner part have respective means for angularly positioning said inner part in said outer part, placing said transverse conduit of the inner part in a determined angular position relative to the outer part; said outer part has a female conical cavity in which are arranged two diametrically opposed conduits for the passage of the strands of the suture thread(s) intended to be connected to the anchor; these conduits are arranged on a diameter which is parallel to the axis of said transverse conduit when said inner part is in said determined angular position; the walls delimiting these conduits on the radially outer side of the outer part form said first wedging surfaces; the surfaces delimiting said female conical cavity between these conduits form two said first engagement surfaces;said inner piece has a male frustoconical portion from which two diametrically opposed bosses project; these bosses are arranged on a diameter parallel to the axis of said transverse conduit; these bosses are intended to engage in said conduits during the movement of said inner piece from said distal non-blocking position to said proximal blocking position, and to wedge the strands of the suture thread(s) between themselves and said walls delimiting the conduits outwards in the radial direction; the bosses constitute said second wedging surfaces, and the surfaces of said male frustoconical portion located outside these bosses form two said second engagement surfaces, intended to engage with said first engagement surfaces in said proximal blocking position.

[0029] The respective means of positioning may in particular consist of two diametrically opposed longitudinal grooves made in the said outer part and corresponding ribs made on the inner part, these ribs forming pads intended to be received in the slide formed by the grooves.

[0030] Advantageously, the outer part has two diametrically opposed longitudinal lights, located opposite the openings of said transverse conduit and extending over the entire displacement of this conduit, from said distal non-blocking position to said proximal blocking position.

[0031] These lights allow the passage of the wire(s) on either side of the inner part when this inner part has an outer diameter adjusted to the inner diameter of the cavity formed by the outer part.

[0032] Preferably, the inner piece has two snap-on projections suitable for snapping behind the edges of the outer piece defining the distal ends of said lights.

[0033] Easy assembly and retention of the inner part in the outer part is thus achieved by snapping it into place.

[0034] Preferably, said inner piece has a pointed distal portion, projecting beyond the outer piece, on the distal side, when said inner piece is in said distal non-blocking position.

[0035] This pointed distal end facilitates the insertion and progression of the anchor into the hole in the bone wall.

[0036] The invention, as set forth above, will be well understood, and other features and advantages thereof will become apparent, by reference to the attached schematic drawing, which represents, by way of non-limiting example, a preferred embodiment of the anchor concerned. There figure 1 It is a perspective view, with an interior room it comprises in an outward position relative to an exterior room it also comprises; the figure 2 is a longitudinal cross-sectional view in a median plane passing through the axis of a transverse conduit formed by said inner part, this inner part being projected relative to said outer part; the figure 3 is a view similar to the figure 2 , along a cutting plane perpendicular to that along the figure 2 ; there figure 4 is a view similar to the figure 1 , after the suture threads have been placed and with the inner piece positioned inside the outer piece, this inner piece being in a distal position so as not to block the suture threads; the figure 5 is a view similar to the figure 4 , according to a cutting plan identical to that according to the figure 2 ; this figure 5 also shows a portion of the end of a bar and a portion of a rod comprising an instrument used for placing the anchor in a bone; the end portion of the bar is seen partly in longitudinal section and partly externally; the figure 6 is a view of the anchor similar to the figure 4 , according to a cutting plan identical to that according to the figure 3 ; there figure 7 This is a view with said inner piece in a proximal position for blocking the suture threads, according to a cutting plane identical to that according to the figure 2 ; and the figure 8 is a similar one to the figure 7 , according to a cutting plan identical to that according to the figure 3 .

[0037] THE figures 1 à 3 represent a medical anchor 1, designed to be inserted into a bone wall and thus fix one or more suture threads 100 to that bone. This anchor 1 is specifically designed to allow the reinsertion of one or more rotator cuff tendons of the shoulder joint onto a humerus.

[0038] Anchor 1 comprises an outer part 2 and an inner part 3 intended to be assembled together.

[0039] The outer piece 2 is designed to be fixed to the bone. Apart from a conical distal portion, it has a cross-section in the shape of a flattened ring, resulting in two flat surfaces 5 on two opposite sides and two curved faces between these flat surfaces 5. Within these curved faces are series of deep grooves 6, delimiting series of ribs 7 between them. The piece 2 is adapted, in a first angular position of insertion into a hole made in the bone wall, to be engaged in this hole, and then to be forcefully rotated within this hole to another angular position, offset by approximately ninety degrees from said first angular position, so as to wedge the anchor 1 into the hole.

[0040] The outer piece 2 forms an internal longitudinal cavity through it, delimiting a proximal cavity 10, an intermediate portion 11 and a distal cavity 12.

[0041] The proximal cavity 10 forms, along the flat surfaces 5, two lateral recesses intended to receive the suture threads, as visible on the figure 4 , and a central mounting cavity including two lateral grooves, intended to receive in a tight fit the distal end of the bar 101, of corresponding section.

[0042] The intermediate portion 11 defines a female conical cavity 15 with a slight slope, on the order of 5 to 10 degrees. This cavity 15 is designed to receive, with a wedging mechanism, a male frustoconical portion 20 comprising the inner piece 3, described later. It forms two diametrically opposed conduits 16, located below the flat surfaces 5 and situated in line with the two aforementioned lateral recesses formed by the cavity 10. These conduits 16 communicate with these lateral recesses and with the distal cavity 12, as visible in the figure 2 and thus allow the passage of the suture thread strands 100 through them, as visible on the figure 5 .

[0043] It appears on the figure 2 that the walls 16a delimiting the bottoms of these conduits 16 are parallel to the longitudinal axis of the outer part 2.

[0044] The distal cavity 12 communicates with the outside of the part 2 by two lights 17, extending through the flats 5, and forms two diametrically opposed grooves 18, extending in a diametrical plane perpendicular to the plane in which the lights 17 extend.

[0045] The inner piece 3 is intended to be inserted and retained in the distal cavity 12 and in the female cavity 15 of the outer piece 2. From the proximal side to the distal side, it has the aforementioned male frustoconical portion 20, a portion through which a transverse conduit 21 passes, a snap-fit ​​portion 22 and a distal portion 23.

[0046] The male frustoconical portion 20 has a slope corresponding to that of the female cavity 15, so as to be able to be received with a wedging action in this cavity. It forms a proximal face perpendicular to its longitudinal axis, against which the rod 102 sliding in the bar 101 is able to bear, as described below. It also has two diametrically opposed bosses 25, arranged on a diameter of the portion 20 parallel to the axis of the transverse conduit 21; these bosses 25 are intended to engage in the conduits 16 when the inner piece 3 passes from the distal non-blocking position shown in the figures 5 And 6 to the proximal blocking position shown on the figures 7 et 8 , thus trapping the strands of the suture threads 100 between each other and the walls 16a forming the bottoms of the conduits 16.

[0047] The transverse conduit 21 passes completely through the inner part 3 and, in the example shown, has a square cross-section. It is intended to be traversed by the suture threads 100, as can be seen in the figures 5 à 8 .

[0048] The snap-fit ​​portion 22 has two snap-fit ​​projections 26 adapted to snap behind the edges of the outer part 2 defining the distal ends of the slots 17, as visible on the figure 5 .

[0049] The distal conical portion 23 is pointed and its peripheral wall comes, in the distal non-blocking position shown on the figure 5 , in the extension of the wall of the distal conical portion of the outer part 2.

[0050] Furthermore, the inner part 3 forms, on its portion delimiting the conduit 21 and on its snap-fit ​​portion 22, two diametrically opposed elongated ribs 27, situated in a plane perpendicular to the plane in which the axis of the conduit 21 extends. These ribs 27 form pads intended to be received in the slide formed by the grooves 18, as visible on the figures 6 et 8 .

[0051] The instrument partially depicted on the figure 5 is consistent with that described in French patent application publication No. 16 52026. Bar 101 has a square cross-section and, as can be seen in the figure 5 , at the level of its distal end portion, two lateral ribs 103. This distal portion of the bar 101 is adapted to be engaged in the aforementioned mounting cavity formed by the proximal cavity 10, with the ribs 103 received in the two aforementioned lateral grooves of this cavity.

[0052] The bar 101 has a longitudinal bore 104 in which the aforementioned rod 102 slides. The rod 102 is movable within this bore 104 between a distal position, in which it bears against the proximal face of the inner piece 3 while the bar 101 is inserted into the mounting cavity, and a proximal position, in which it is retracted relative to this proximal face. In its distal position, the rod 102 maintains the inner piece 3 in the distal non-blocking position and, in its proximal position, does not impede the movement of the inner piece 3 towards the proximal blocking position visible in the figures 7 et 8 .

[0053] The instrument includes means (not shown, described in French patent application publication No. 16 52026) for selectively locking the rod 102 relative to the bar 101 in the distal position of the rod. These means may, in particular, take the form of a drawer carried transversely by a handle attached to the bar 101, this drawer being movable transversely to the longitudinal axis of the bar 101; the drawer has a solid wall portion and a wall portion pierced by a hole with a cross-section larger than that of the rod 102; in one sliding position, the solid wall portion of this drawer is located in the immediate vicinity of the proximal end of the rod 102 and thus blocks any recoil of this rod, and in another sliding position of this drawer, the hole formed by this drawer is located opposite the rod 102 and allows the rod to recoil.

[0054] In practice, the suture threads 100 are passed through the outer piece 2, then through the transverse channel 21, then again through the outer piece 2, and the inner piece 3 is inserted into the distal cavity 12, with the ribs 27 in the grooves 18, until the projections 26 click beyond the edges of piece 2, defining the distal ends of the lumens 17. The anchor 1 is then in the state visible on the figures 4 à 6 .

[0055] To insert the anchor 1 into a bone cavity, the free end portion of the bar 101 is engaged in said mounting cavity and the rod 102 is locked in its distal position, thus maintaining the inner piece 3 in said distal non-locking position visible on the figures 5 And 6 .

[0056] Once the anchor 1 is inserted into the bone, the retraction of the rod 102 is unlocked, allowing the inner piece 3 to move towards the proximal locking position visible on the figures 7 et 8 when traction is applied to the sutures 100, particularly during the repositioning of the ligaments on the bone. In this position, the sutures 100 are pinched between the bottoms 16a of the conduits 16 and the radially external faces of the bosses 25, these bottoms and faces constituting respective clamping surfaces for the sutures 100.

[0057] Simultaneously, the parts of the male truncated conical portion 20 not opposite the conduits 16 engage in the parts of the cavity 15 located outside the conduits 16, until they jam, ensuring immobilization of the inner part 3 relative to the outer part 2 in this proximal position.

[0058] The invention provides a medical anchor with significant advantages over similar anchors of the prior art, including: to preserve the strands of the suture thread(s) 100 from deterioration resulting from the placement of the anchor, due to the fact that these threads are placed inside the anchor 1; to include externally a structure allowing the perfect anchoring of the anchor 1 in a bone, in particular by wedging resulting from a pivoting on a quarter turn; to maintain a relatively easy placement of the suture thread(s) in it, due to its structure in two pieces 2, 3 that can be assembled; to have an easy assembly of these two pieces; to allow pressure to be exerted on a relatively large portion of the suture thread(s) 100, ensuring perfect wedging of this or these thread(s), without risk of shearing.

[0059] Anchor 1 has been described above with reference to a preferred realization form; it goes without saying that this description is in no way limiting.

Claims

1. Anchor (1) for medical use, intended to be inserted into a bony wall, comprising two pieces (2, 3) intended to be assembled together, namely an outer piece (2), intended to be fixed to the bone, which forms an internal longitudinal cavity through it, and an inner piece (3) intended to be inserted and retained in said cavity of the outer piece (2), which forms a transverse conduit (21) passing through it from one side to the other; at least one suture thread (100) is intended to be engaged in said cavity from the proximal side of the outer piece (2), to be engaged through said transverse conduit (21) and to emerge from said outer piece (2) through said proximal side; wherein: - the outer piece (2) forms at least one first wedging surface (16a) arranged in the longitudinal direction of the outer piece (2), and the inner piece (3) forms at least one second wedging surface (25) located on the proximal side with respect to the transverse conduit (21), this second wedging surface (25) being arranged in the longitudinal direction of the inner piece (3); - said at least one suture thread (100) is intended to extend along said first wedging surface (16a) and along said second wedging surface (25); - the inner piece (3) is movable relative to the outer piece (2) between a distal position in which the suture thread (100) is not blocked, in which said second wedging surface (25) is at a distance from said first wedging surface (16a) that does not wedge the suture, and a proximal position that blocks the suture thread (100), in which said second wedging surface (25) is at a distance from said first wedging surface (16a) that wedges the suture; said outer piece (2) comprising two said first wedging surfaces (16a), diametrically opposed, and said inner piece (3) comprising two said corresponding second wedging surfaces (25), at least one of said first and second wedging surfaces (16a, 25) being inclined relative to the longitudinal axis of the anchor (1); and characterized in that: - said outer piece (2) presents a female conical cavity (15) in which two diametrically opposed conduits (16) are arranged; - the inner piece (3) presents a male truncated conical portion (20) with a slope corresponding to that of said female conical cavity (15), said male truncated conical portion (20) comprising two diametrically opposed bosses (25) arranged along a diameter of the male truncated cone portion (20) parallel to the axis of the transverse conduit (21), the bosses (25) being designed to engage in said conduits (16) when the inner piece (3) moves from the distal non-locking position to the proximal locking position, thereby wedging the suture thread (100) between the radially outer faces of the bosses (25) and the bottoms (16a) of the conduits (16); - the bottoms (16a) and the radially outer faces of the bosses (25) constitute respectively first and second wedging surfaces.

2. Anchor (1) according to claim 1, characterized in that said outer piece (2) forms at least a first engagement surface (15a), distinct from said first wedging surface (16a), and in that said inner piece (3) forms at least a second engagement surface (20a), distinct from said second wedging surface (25), said respective engagement surfaces (15a, 20a) coming into mutual engagement in said proximal locking position and achieving immobilization of said inner piece (3) relative to said outer piece (2) in this position.

3. Anchor (1) according to claim 2, characterized in that said first and second engagement surfaces (15a, 20a) are inclined relative to the longitudinal axis of the anchor (1) so as to be capable, when the inner piece (3) is moved proximally inside the outer piece (2), of coming into a mutual wedging state that determines said proximal locking position, and in that said respective wedging surfaces (16a, 25) are arranged such that, in this proximal locking position, there exists a space between them having a thickness on the order of 10 to 40% of the diameter of a suture thread (100).

4. Anchor (1) according to claim 2 or claim 3, characterized in that: - said outer piece (2) and said inner piece (3) comprise respective means (18, 27) for angular positioning of said inner piece (3) within said outer piece (2), placing said transverse conduit (21) of the inner piece (3) in a predetermined angular position relative to the outer piece (2); - the conduits (16) allow passage of the strands of the suture(s) (100) intended to be connected to the anchor (1); said conduits (16) are arranged along a diameter that is parallel to the axis of said transverse conduit (21) when said inner piece (3) is in said predetermined angular position; the surfaces delimiting said female conical cavity (15) between these conduits (16) form two said first engagement surfaces (15a); - the surfaces of said male truncated conical portion (20) located outside these bosses (25) form two said second engagement surfaces (20a), intended to come into engagement with said first engagement surfaces (15a) in said proximal locking position.

5. Anchor (1) according to claim 4, characterized in that said respective positioning means consist of two diametrically opposed longitudinal grooves (18) formed in said outer piece (2) and corresponding ribs (27) formed on the inner piece (3), these ribs (27) forming pads intended to be received in the slide formed by the grooves (18).

6. Anchor (1) according to any one of claims 1 to 5, characterized in that the outer piece (2) comprises two diametrically opposed longitudinal slots (17), positioned opposite the openings of said transverse conduit (21) and extending over the entire movement of this conduit (21), from said distal non-locking position to said proximal locking position.

7. Anchor (1) according to claim 6, characterized in that the inner piece (3) comprises two latching projections (26) capable of snapping behind the edges of the outer piece (2) defining the distal ends of said slots (17).

8. Anchor (1) according to any one of claims 1 to 7, characterized in that said inner piece (3) comprises a distal portion (23) pointedly protruding beyond the outer piece (2) on the distal side, when said inner piece (3) is in said distal non-locking position.