JP7624711B2 - Suture anchor and suture anchor system - Google Patents

Description

The present invention relates to a suture anchor and a suture anchor system.

A suture anchor is a type of implant used to promote improvement of joint function by fixing damaged soft tissues (ligaments, tendons, muscles, etc.) to the bone using sutures extending from the anchor after the anchor is embedded in the bone (Patent Document 1). Suture anchors are used, for example, in surgery to repair a torn rotator cuff in the shoulder joint.

Patent Document 1 discloses a suture anchor whose outer circumferential surface is threaded, which has two through holes spaced apart in the axial direction on the side surface near the tip, and a suture locking portion (bridge) defined between the through holes. The suture anchor described in Patent Document 1 has an insertion hole extending from the rear end toward the front. The suture is inserted into the insertion hole of the suture anchor, folded back and hooked onto the suture locking portion, and set in the suture anchor so that both ends extend outward from the hole.

Special Publication No. 2013-509257

Generally, suture anchors are embedded in bones by rotating them using a dedicated insertion tool. That is, a screwdriver-like insertion tool with a tip shape that corresponds to the entrance shape of the insertion hole of the suture anchor is fitted into the insertion hole, and the insertion tool applies a rotational torque to the suture anchor, embedding the suture anchor in the bone. The entrance shape of the insertion hole of the suture anchor is, for example, a hexagonal star-shaped recess in the shape of a screw head.

At this time, there is a risk that the suture anchor may be damaged by the rotational torque applied by the insertion tool. Specifically, there is a risk that the inner surface of the insertion hole or the area near the entrance opening, which comes into direct contact with the outer surface of the insertion tool and through which the rotational torque of the insertion tool is transmitted, may be damaged.

In addition, with the suture anchor described in Patent Document 1, there is a risk that a portion of the edge that is the boundary between the through hole and the suture locking portion and the threaded portion will lock onto the inner surface of the bone when the suture anchor is rotated, and be damaged.

The present invention aims to provide a suture anchor that is less likely to be damaged when embedded in bone.

According to one aspect of the present invention, there is provided a suture anchor comprising a hollow anchor body member whose front end is closed and whose outer peripheral surface is provided with a threaded portion having a ridge portion and formed in a screw shape, and a through hole is provided through the outer peripheral surface of the anchor body member so as to extend along an axis perpendicular to the central axis, and the suture anchor is characterized in that the end of the ridge portion extending toward the through hole is formed with a sloped portion whose height gradually decreases toward the through hole.

The inclined portion may be formed only at the end of the crest portion located further axially rearward in the corresponding ridge portion through the through hole. The crest portion may be formed so that its height gradually decreases toward the tip of the anchor body member. The outer shape of the anchor body member at the threaded portion may be tapered toward the tip. An insertion hole into which the tip of an insertion tool fits may be provided at the rear end of the anchor body member, and the entrance portion of the insertion hole may be formed in a shape consisting of a combination of a circle and a plurality of arcs that circumscribe the circle and are equally spaced apart.

According to another aspect of the present invention, there is provided a suture anchor system comprising the suture anchor, a suture, and an insertion tool.

The aspects of the present invention have the common effect of providing a suture anchor that is less likely to be damaged when embedded in bone.

FIG. 1 is a perspective view of a suture anchor system in accordance with an embodiment of the present invention. FIG. 2 is a perspective view of the suture anchor of the present invention. FIG. 3 is a front view of the suture anchor of the present invention. FIG. 4 is a longitudinal cross-sectional view of the suture anchor of the present invention taken along line AA of FIG. FIG. 5 is a longitudinal cross-sectional view of a suture anchor of the present invention with a suture loaded therein. FIG. 6 is a longitudinal cross-sectional view of a suture lock according to another embodiment of the present invention. FIG. 7 is a bottom view of the suture anchor of the present invention.

The following describes in detail an embodiment of the present invention with reference to the drawings. Corresponding components are designated by the same reference symbols throughout the drawings.

FIG. 1 is a perspective view of a suture anchor system 100 according to an embodiment of the present invention. The suture anchor system 100 includes an insertion tool 1, a suture 2, and a hollow suture anchor 10. In this specification, the side of the insertion tool 1 and the suture anchor 10 in the axial direction, i.e., the tip side, is defined as the "front" side, and the opposite side is defined as the "rear" side.

The insertion tool 1 has a gripping portion 3 that is held by the user and a hollow shaft portion 4. The suture 2 passes through the inside of the gripping portion 3 and the shaft portion 4, and is inserted into the inside of the suture anchor 10 and locked therein. The suture anchor 10 is embedded in the bone by rotating it using the insertion tool 1. The front end of the insertion tool 1, i.e., the front end of the shaft portion 4, is formed to fit into an insertion hole 16 provided on the rear end surface of the suture anchor, which will be described later.

Figure 2 is a perspective view of the suture anchor 10, Figure 3 is a front view of the suture anchor 10, Figure 4 is a longitudinal cross-sectional view of the suture anchor 10 taken along line A-A in Figure 3, and Figure 5 is a longitudinal cross-sectional view of the suture anchor 10 with the suture 2 set therein.

The suture anchor 10 is formed from a biomaterial. The suture anchor 10 is preferably formed from a bioabsorbable biomaterial such as a synthetic polymer, but may also be formed from a non-bioabsorbable biomaterial such as a metal or ceramic.

The suture anchor 10 has a hollow anchor body member 11 and a suture locking portion 20. The anchor body member 11 has a front end 12 closed, and a threaded portion 13 formed in a screw shape on the outer circumferential surface. The threaded portion 13 has a helical crest 14 and a valley portion 15 provided between the crests 14. The rear end surface of the anchor body member 11 is provided with an insertion hole 16 extending forward. The crest 14 of the threaded portion 13 may be formed as a reverse tooth thread or a reverse angle thread in which the flank angle of the pressure side flank, i.e., the flank on the side that directly receives the load when fastened and fixed, is formed at a negative (minus) angle. This makes it possible to make the suture anchor 10 less likely to come out after it is embedded in the bone.

4, a through hole 17 is provided through the outer peripheral surface of the anchor body member 11 so as to extend along an orthogonal axis P perpendicular to the central axis C of the suture anchor 10. In addition to the through hole 17, a plurality of side holes 18 communicating with the inside of the through hole 17 are provided on the outer peripheral surface of the anchor body member 11. The plurality of side holes 18 are aligned at equal intervals along the axial direction and circumferential direction of the suture anchor 10 on the outer peripheral surface of the anchor body member 11. Specifically, as shown in FIG. 2, the through hole 17 and one side hole 18 are aligned along the axial direction of the suture anchor 10 on the outer peripheral surface of the anchor body member 11, and are similarly aligned on the opposite side by 180 degrees, and at a position rotated by 90 degrees, three side holes are aligned, but the arrangement of the side holes 18 is not limited thereto. Some of the side holes 18 in FIG. 2 reach the insertion hole 16, while others reach the through hole 17, but all of them communicate with the inside of the through hole 17. The number of side holes 18 does not have to be multiple, but may be one, or may be one that reaches either the insertion hole 16 or the through hole 17. The side hole 18 is preferably hollowed out in a cylindrical shape. By providing the side hole 18 in the suture anchor 10, after the suture anchor 10 is embedded in the bone, bone is formed in the side hole 18 due to bone conduction, making it more difficult for the suture anchor 10 to come out.

Inside the through hole 17, there is provided a suture locking portion 20 that locks the suture 2 inserted from the rear end of the anchor body member 11 into the inside. The suture locking portion 20 is formed in a columnar shape that connects the opposing inner surfaces of the through hole 17. Therefore, when viewed from the direction along the orthogonal axis P, the front and rear portions of the suture locking portion 20 penetrate the through hole 17 (through hole 17a and through hole 17b) as shown in Figure 3. In other words, the suture locking portion 20 is defined between the two through holes 17a and 17b that are spaced apart in the axial direction.

As shown in FIG. 4, the suture locking portion 20 has a convex portion 20a formed in a convex curve on the front side and a tapered portion 20b formed in a tapered shape toward the rear on the rear side in a cross section including the central axis C and the orthogonal axis P.

When setting the suture 2 in the suture anchor 10, first one end of the suture 2 is inserted into the insertion hole 16 and fed into the interior, and then protrudes outward from the through hole 17b on the rear end side. Next, one end of the suture 2 is inserted into the through hole 17a on the front end side and protrudes to the opposite side, and then is inserted again into the insertion hole 16 from the through hole 17b on the rear end side. This allows the suture 2, which has been folded back to form a loop, to be hooked onto the suture locking portion 20.

At this time, since the suture locking portion 20 is formed in the cross-sectional shape as described above, the suture 2 can be set more smoothly in the suture anchor 10. That is, one end of the suture 2 inserted from the insertion hole 16 hits the surface of the tapered portion 20b, specifically, one of the upper or lower inclined surfaces in FIG. 4, and protrudes outward from the suture anchor 10 from above or below. Since the surface of the tapered portion 20b is an inclined surface, the suture anchor 10 can be smoothly changed in the outward direction. Furthermore, when one end of the suture 2 is inserted into the through hole 17a on the front end side, the one end of the suture 2 hits the surface of the convex portion 20a formed in a convex curved shape, and can be smoothly inserted. Next, when one end of the suture 2 is inserted into the through hole 17b on the rear end side, the one end of the suture 2 hits the other of the upper or lower inclined surfaces of the tapered portion 20b and is guided into the insertion hole 16. As a result, the suture 2 can be set more smoothly into the suture anchor 10.

The convex portion 20a may have any curvature or shape as long as it is formed in a convex curved shape. For example, the convex portion 20a may be formed by a combination of curves having multiple curvatures in a cross section including the central axis C and the orthogonal axis P. The tapered portion 20b does not need to have a sharp tip on the rear side, and may be slightly rounded. In addition to being tapered linearly toward the rear side tip as shown in FIG. 4, the tapered portion 20b may be tapered convexly toward the rear side tip (FIG. 6(A)) or concavely toward the rear side tip (FIG. 6(B)). In this specification, the convex or concave tapered form shown in FIG. 6 is also referred to as a tapered form.
The suture anchor of the present invention can be manufactured, for example, by one-piece molding using a lathe to cut a round bar-shaped material, but it may also be manufactured by manufacturing the components separately and then fusing them together.

When the suture anchor 10 is embedded in a bone, the surrounding bone is cut as the suture anchor 10 advances, generating powdered bone chips. If the bone chips get between the outer surface of the suture anchor 10 and the bone, they will create resistance when the suture anchor 10 advances, and may cause damage to the suture anchor 10. As described above, the through hole 17 is penetrated at the front and rear portions of the suture locking portion 20, and a tapered portion 20b is provided, so that the space in the through hole 17 around the suture locking portion 20 that can accommodate bone chips generated when the suture anchor 10 is embedded is increased. As a result, even if bone chips are generated, their impact is reduced.

As shown in FIG. 5, the suture locking portion 20 is formed so that the suture 2 does not protrude outside the anchor body member 11 when it is locked to the suture locking portion 20. In other words, the suture locking portion 20 is defined with a size and shape that prevents the suture 2 from protruding outside the anchor body member 11 when it is locked to the suture locking portion 20. This prevents the suture 2 from rubbing against the bone when the suture anchor 10 is embedded in the bone, reducing the insertion resistance of the suture anchor 10 and preventing wear of the suture 2 and the generation of bone chips.

2, the end of the peak 14 extending toward the through hole 17 is formed with an inclined portion 21 whose height gradually decreases toward the through hole 17. In this embodiment, as shown in FIG. 3, the inclined portion 21 is formed only at the end of the peak 14b located further rearward in the axial direction in the peaks 14a and 14b corresponding to each other through the through hole 17. However, the inclined portion 21 may also be formed at the end of the peak 14a located further forward. By providing the inclined portion 21 on the peak 14 near the through hole 17, when the suture anchor 10 is embedded in the bone while rotating, the bone is prevented from being cut by the end of the peak 14, and bone chips are prevented from being generated. As a result, the resistance at the time of insertion when the suture anchor 10 is embedded is reduced, and the suture anchor 10 can be embedded more smoothly. The inclined portion 21 may be formed not only in the inclined surface shape as shown in FIG. 2, but also in the convex curved surface shape that curves toward the inside of the through hole 17.

As shown by line L1 in FIG. 3, the series of peaks 14 are formed so that their height, i.e., the height of the peaks 14 from the adjacent valleys 15, gradually decreases toward the tip of the anchor body member 11. Furthermore, as shown by line L2 in FIG. 3, the outer shape of the anchor body member 11 at the threaded portion 13 is tapered toward the tip. In other words, the outer diameter of the valleys 15 is formed so that it gradually becomes smaller toward the tip. As a result, resistance during insertion when embedding the suture anchor 10 is suppressed, and the suture anchor 10 can be embedded more smoothly.

The height of the peaks 14 may be uniform and the outer shape of the anchor body member 11 may be tapered toward the tip. Alternatively, the height of the peaks 14 may be gradually decreased toward the tip of the anchor body member 11 and the outer diameter of the anchor body member 11 may be uniform toward the tip.

7 is a bottom view of the suture anchor 10. As shown in FIG. 7, the entrance portion of the insertion hole 16 is formed in a shape consisting of a combination of a circle 16a and one or more, specifically six, arcs 16b that circumscribe the circle 16a and are equally spaced apart. The arcs 16b can be semicircular, for example. The center of the circle 16a coincides with the axial center of the suture anchor 10. As described above, the front end of the insertion tool 1 is formed to fit into the insertion hole 16 provided on the rear end surface of the suture anchor 10. By forming the entrance portion of the insertion hole 16 in the above-mentioned shape, when the front end of the insertion tool 1 is fitted and rotated, the torque resistance is dispersed, and damage to the suture anchor 10 is prevented.

The tip of the front end 12 of the suture anchor 10 is formed in a hemispherical shape and has a straight portion continuing to the rear, so that the suture anchor 10 can be easily aligned with a pilot hole provided in the bone and can be smoothly inserted. The tip of the front end 12 may be in a spindle shape, cone shape, or other shape as long as it has a shape that performs this function. The threaded portion may be formed as a single thread that advances one pitch with one turn of the suture anchor 10, or as a multiple-start thread with two or more starts. This allows the suture anchor 10 to be embedded with a small number of turns.

The above-described embodiment provides a suture anchor that is easy to set the suture and reduces the effects of bone chips, and also provides a suture anchor that is less likely to be damaged when embedded in the bone.

REFERENCE SIGNS LIST 1 insertion tool 2 suture 3 gripping portion 4 shaft portion 10 suture anchor 11 anchor body member 12 front end portion 13 threaded portion 14 crest portion 14a crest portion 14b crest portion 15 valley portion 16 insertion hole 16a circle 16b semicircle 17 through hole 17a through hole 17b through hole 18 lateral hole 20 suture locking portion 20a convex portion 20b tapered portion 21 inclined portion 100 suture anchor system C central axis P orthogonal axis L1 line L2 line

Claims (6)

A suture anchor comprising: a hollow anchor body member having a front end that is closed and a threaded portion formed in a screw shape with a ridge on an outer circumferential surface thereof, the anchor body member having a through hole penetrating the outer circumferential surface of the anchor body member so as to extend along an axis perpendicular to a central axis,
A suture anchor, characterized in that an end of the peak portion extending toward the through hole is formed with an inclined portion whose height gradually decreases toward the through hole. The suture anchor according to claim 1 , wherein the inclined portion is formed only at an end portion of the peak portion that is positioned more rearward in the direction of the central axis in the peak portion that corresponds to the through hole. The suture anchor according to claim 1 or 2, wherein the peaks are formed so that their height gradually decreases toward the tip of the anchor body member. The suture anchor according to any one of claims 1 to 3, wherein the outer shape of the anchor body member in the threaded portion is tapered toward the tip. A suture anchor according to any one of claims 1 to 4, wherein the rear end of the anchor body member is provided with an insertion hole into which the tip of an insertion tool fits, and the entrance portion of the insertion hole is formed in a shape that is a combination of a circle and a number of arcs that circumscribe the circle and are equally spaced apart. A suture anchor system comprising: a suture anchor according to any one of claims 1 to 5; a suture; and an insertion tool for embedding the suture anchor into a bone .

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