Suture anchor and suture anchor system

Abstract

To provide a suture anchor that is hardly damaged at the time of being embedded into a bone.SOLUTION: A suture anchor comprises a hollow anchor body component 11, a front end part 12 of which is closed, and an outer peripheral surface of which is provided with a screw part 13 comprising a crest part 14 and formed in a screw shape, and which anchor body component 11 is provided with a through hole 17 passing through an outer peripheral surface of the anchor body component 11 so as to extend along an orthogonal axis line P orthogonal to a center axis line C. At an end of the crest part 14 extending toward the through hole 17, an inclined part 21 whose height reduces gradually toward the through hole 17 is formed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to suture anchors and suture anchor systems. [Background technology]

[0002] A suture anchor is a type of implant used to promote improvement of joint function by embedding an anchor in a bone and then fixing surrounding damaged soft tissues (ligaments, tendons, muscles, etc.) to the bone using a suture extending from the anchor (Patent Document 1). The suture anchor is used, for example, in surgery to repair a torn rotator cuff in the shoulder joint.

[0003] Patent Document 1 discloses a suture anchor having an outer peripheral surface formed in a threaded shape, two through holes provided axially spaced apart on a 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 forward from the rear end. The suture is inserted into the insertion hole of the suture anchor, folded back and hooked on the suture locking portion, and set in the suture anchor so that both ends extend outward from the hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2013-509257 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, suture anchors are embedded in bones by rotating them using a dedicated insertion tool. That is, a screwdriver-like insertion tool having a tip shape corresponding 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, thereby 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.

[0006] At this time, there is a risk that the rotational torque applied by the insertion tool may damage the suture anchor, specifically, the inner surface of the insertion hole or a portion near the entrance opening that 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.

[0007] Furthermore, with respect to the suture anchor described in Patent Document 1, there is a risk that part 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.

[0008] An object of the present invention is to provide a suture anchor that is less likely to be damaged when embedded in bone. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a suture anchor comprising: a hollow anchor body member having a closed front end and a threaded portion having a ridge portion formed into a screw shape on its outer circumferential surface, 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, the suture anchor being characterized in that an inclined portion is formed at an end of the ridge portion extending toward the through hole, the height of which gradually decreases toward the through hole.

[0010] The inclined portion may be formed only at the end of the crest portion located further rearward in the axial direction in the corresponding crest portion via 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 circumscribing the circle and equally spaced apart.

[0011] According to another aspect of the present invention, there is provided a suture anchor system comprising the suture anchor described above, a suture, and an insertion tool. Effect of the Invention

[0012] The aspects of the present invention have a common effect of providing a suture anchor that is less likely to be damaged when embedded in bone. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view of a suture anchor system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the suture anchor of the present invention. [Diagram 3] FIG. 3 is a front view of the suture anchor of the present invention. [Figure 4] FIG. 4 is a longitudinal cross-sectional view of the suture anchor of the present invention taken along line AA of FIG. [Diagram 5] FIG. 5 is a longitudinal cross-sectional view of a suture anchor of the present invention with a suture set therein. [Figure 6] FIG. 6 is a longitudinal cross-sectional view of a suture lock according to another embodiment of the present invention. [Figure 7] FIG. 7 is a bottom view of the suture anchor of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Corresponding components are designated by common reference numerals throughout the drawings.

[0015] 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 on which the suture anchor 10 is located in the axial direction of the insertion tool 1 and the suture anchor 10, i.e., the tip side, is defined as the "front" side, and the opposite side is defined as the "rear" side.

[0016] The insertion tool 1 has a gripping portion 3 that is gripped by a user, and a hollow shaft portion 4. A suture 2 is inserted into and locked in the suture anchor 10 through the inside of the gripping portion 3 and the shaft portion 4. 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 so as to fit into an insertion hole 16 provided in the rear end surface of the suture anchor, which will be described later.

[0017] FIG. 2 is a perspective view of the suture anchor 10, FIG. 3 is a front view of the suture anchor 10, FIG. 4 is a longitudinal cross-sectional view of the suture anchor 10 taken along line AA in FIG. 3, and FIG. 5 is a longitudinal cross-sectional view of the suture anchor 10 with a suture 2 set therein.

[0018] 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 be formed from a non-bioabsorbable biomaterial such as a metal or ceramic.

[0019] 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 portion 12 that is closed, and a threaded portion 13 formed in a screw shape is provided on the outer circumferential surface. The threaded portion 13 has a helical crest portion 14 and a valley portion 15 provided between the crest portions 14. An insertion hole 16 extending forward is provided on the rear end surface of the anchor body member 11. The crest portion 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 a 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.

[0020] 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 lateral 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 lateral 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 lateral 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 lateral holes are aligned, but the arrangement of the lateral holes 18 is not limited thereto. Some of the lateral 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. Note that the number of side holes 18 does not have to be multiple, and there may be only one, or only one that reaches either the insertion hole 16 or the through-hole 17. Such 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 inside the side hole 18 due to osteoconduction, making the suture anchor 10 less likely to come out.

[0021] A suture locking portion 20 that locks the suture 2 inserted from the rear end of the anchor body member 11 into the through hole 17 is provided inside the through hole 17. 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 through hole 17 is penetrated at the front and rear portions of the suture locking portion 20 (through hole 17a and through hole 17b) as shown in Fig. 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.

[0022] As shown in FIG. 4, in a cross section including the central axis C and the orthogonal axis P, the suture locking portion 20 has a convex portion 20a formed in a convex curved shape on the front side and a tapered portion 20b formed in a tapered shape toward the rear on the rear side.

[0023] 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 inside, 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. In this way, the suture 2, which has been folded back to form a loop, can be hooked onto the suture locking portion 20.

[0024] 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 direction of the suture anchor 10 can be smoothly changed outward. 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 in the suture anchor 10 more smoothly.

[0025] 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 a plurality of 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 as 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.

[0026] 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 provide resistance when the suture anchor 10 advances, and may cause damage to the suture anchor 10. As described above, the through-hole 17 has the front and rear portions of the suture locking portion 20 penetrating therethrough, and the 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.

[0027] 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.

[0028] As shown in FIG. 2, an inclined portion 21 is formed at the end of the peak 14 extending toward the through hole 17, the height of which 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 the generation of bone chips is prevented. 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 an inclined surface shape as shown in FIG. 2, but also in a convex curved surface shape that curves toward the inside of the through hole 17.

[0029] As shown by line L1 in Fig. 3, the series of peaks 14 are formed so that their height, i.e., the height of each peak 14 from the adjacent valley 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 valley 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 reduced, and the suture anchor 10 can be embedded more smoothly.

[0030] The height of the ridges 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 ridges 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.

[0031] FIG. 7 is a bottom view of the suture anchor 10. As shown in FIG. 7, the entrance portion of the insertion hole 16 is provided in a shape consisting of a combination of a circle 16a and one or more, specifically six, circular arcs 16b that circumscribe the circle 16a and are arranged at equal intervals. The circular arcs 16b can be, for example, semicircular. 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 in 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 fits and is rotated, torque resistance is dispersed, and damage to the suture anchor 10 is prevented.

[0032] Since the tip of the front end 12 of the suture anchor 10 is formed in a hemispherical shape and has a straight portion continuing rearward, the suture anchor 10 can be easily aligned with a pilot hole provided in a bone and smoothly inserted. The tip of the front end 12 may be in any other shape, such as a spindle shape or a cone shape, so long as it has a shape that performs the above-mentioned function. The threaded portion may be formed as a single-start thread that advances one pitch per 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.

[0033] According to the above-described embodiment, it is possible to provide a suture anchor that allows easy setting of a suture and reduces the effects of bone chips, and also to provide a suture anchor that is less likely to be damaged when embedded in a bone. [Explanation of symbols]

[0034] 1 Insertion tool 2 Sutures 3 Gripping part 4 Shaft section 10 Suture anchor 11 Anchor body member 12 Front end 13 Threaded part 14 Yamabe 14a Mountain 14b Mountain 15 Valley 16 Insertion Hole 16a Circular 16b Semicircle 17 Through hole 17a Through hole 17b Through hole 18 Side Cave 20 Suture retainer 20a Convex part 20b Tapered section 21 Slope 100 Suture Anchor System C center axis P orthogonal axis L1 line L2 line

Claims

1. 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.

2. 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.

3. 3. The suture anchor according to claim 1, wherein the height of the peaks is gradually reduced toward the tip of the anchor body member.

4. 4. The suture anchor according to claim 1, wherein the outer shape of the anchor body member at the threaded portion is tapered toward the tip.

5. 5. The suture anchor according to claim 1, wherein an insertion hole into which a tip of an insertion tool fits is provided at a rear end of the anchor body member, and an entrance portion of the insertion hole is formed in a shape consisting of a combination of a circle and a plurality of circular arcs that circumscribe the circle and are equally spaced apart.

6. 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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