US20030171778A1 - Knotless suture anchor system and method of use - Google Patents

Abstract

A suture anchor system includes a suture anchor, a first loop of suture thread attached to the suture anchor, a suture needle, and a second loop of suture thread which is attached to the suture needle. The first and second suture loops are interlocked with one another. The suture anchor is preferably bioabsorbable, and it has a flared feature on one side of the second or proximal end thereof. The flared feature renders the suture anchor asymmetrical in a plane that includes the longitudinal axis of the anchor. A method for anchoring soft tissue is also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of application Ser. No. 09/691,498, filed Oct. 18, 2000, titled “Knotless Suture Anchor System And Method Of Use,” which is hereby incorporated by reference in its entirety.[0001]
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
• Not Applicable.[0002]
FIELD OF THE INVENTION
• The invention relates to a knotless suture anchor system for attaching soft tissue to hard bone, and to methods for attaching soft tissue to hard bone.[0003]
BACKGROUND OF THE INVENTION
• Soft tissues, such as ligaments, tendons and muscles, are attached to a large portion of the human skeleton. In particular, many ligaments and tendons are attached to the bones which form joints, such as shoulder and knee joints. A variety of injuries and conditions require attachment or reattachment of a soft tissue to bone. For example, when otherwise healthy tissue has been torn away from a bone, surgery is often required to reattach the tissue to the bone to allow healing and a natural reattachment to occur.[0004]
• A number of devices and methods have been developed to attach soft tissue to bone. These include screws, staples, cement, suture anchors, and sutures alone. Some of the more successful methods involve use of a suture anchor to attach a suture to the bone, and tying the suture in a manner that holds the tissue in close proximity to the bone.[0005]
• The tissue may be attached to the bone during open surgery, or during closed (e.g., arthroscopic) surgical procedures. Closed surgical procedures are preferred since they are less invasive and are less likely to cause patient trauma. In a closed surgical procedure, the surgeon performs diagnostic and therapeutic procedures at the surgical site through small incisions, called portals, using instruments specially designed for this purpose. One problem encountered in the less invasive, closed surgical procedures is that the surgeon has significantly less room to perform the required manipulations at the surgical site. Thus, devices and methods are needed which will allow a surgeon to effectively and easily attach tissue to bone in the small spaces provided by less invasive surgical procedures.[0006]
• Conventional methods for attaching soft tissue to bone typically require that the surgeon tie a knot in the suture thread to attach the suture to an anchor, or to attach the tissue to the bone using the suture. Knot tying at the surgical site in closed surgical procedures, and even in open surgery, is difficult and time consuming due to inherent space constraints. Further, knots and other bulky attachment means can irritate tissue over time.[0007]
• Knotless suture anchor systems have been developed for use with closed surgical procedures, and U.S. Pat. No. 5,569,306 provides one example of such a system. A further knotless suture anchor and system is disclosed in U.S. Pat. No. 5,782,864. Although generally useful, such systems can be limited to use only with certain types or shapes of tissue, or to use with certain anatomical structures. Proper attachment of soft tissue requires that it be placed in the anatomically correct position to promote optimal healing.[0008]
• Further, some conventional knotless suture anchor systems may require, in order to attach a broader array of tissue shapes to bone, that the suture anchor pass though the tissue to be attached. This is undesirable because it unnecessarily irritates the injured tissue and it requires opening a much larger hole in the tissue.[0009]
• There is thus a need for an improved system for anchoring soft tissue to bone which reduces or eliminates the need to tie suture knots at the surgical site. Further, there is a need for an improved system for anchoring soft tissue to hard bone which is easy and fast to deploy and requires few tools. It would also be advantageous to provide a fully absorbable knotless suture anchor and system.[0010]
SUMMARY OF THE INVENTION
• The present invention provides a system for anchoring tissue to bone including a suture anchor, a first suture loop attached to the suture anchor, a suture needle and a second suture loop attached to the suture needle and interlocked with the first suture loop. The second suture loop may be formed by attaching two free ends of a length of suture thread directly to the suture needle, or by attaching the two free ends within a suture closure which may then be attached to the suture needle. In a preferred embodiment, the suture anchor is entirely bioabsorbable. A method is also provided by which a detached tissue may be securely attached to bone in an anatomically correct position without the need to tie a knot.[0011]
• In an exemplary embodiment, the system includes a suture anchor having a first, leading end, a second, trailing end, and two opposed sides between the first and second ends. The second end has a flared portion that renders the suture anchor asymmetrical in a plane that includes the longitudinal axis. The first suture loop is attached at a position between the first and second ends of the suture anchor and is interlocked with the second suture loop. The second suture loop is attached to a trailing end of the suture needle. The asymmetrical shape of the suture anchor assists in securing the anchor within bone. When tension and deflection by the inserter is applied to the suture anchor, after the anchor is positioned within bone, the anchor undergoes a toggling action, or rotation which results in the anchor being oriented in a direction that is not parallel with the longitudinal axis of the anchor-seating bore. This toggling of the anchor causes the anchor to become lodged within the bone. Thus, the anchor can be firmly embedded within bone without the need for ancillary anchoring structure such as arcs.[0012]
• In an embodiment that is particularly useful in closed surgery, the second suture loop is formed using a suture loop closure and is attached to a hollow suture needle by means of a slot provided in a wall of the hollow needle. This embodiment may also employ an actuator, disposed within the hollow needle, which can be selectively deployed to disengage the second suture loop from the needle. The hollow needle used with this embodiment preferably is part of an elongate tool, such as a suture inserter, that is useful in closed surgical procedures. The hollow needle typically forms the distal end of such a tool.[0013]
• The system may be used in a method wherein the suture needle and the attached second suture loop are passed through a detached segment of tissue. The second suture loop is pulled through the detached tissue until a portion of the interlocked first suture portion of the first suture loop is seated within a suture thread-engaging groove at the first end of the anchor. The anchor is then tapped into a predrilled bore in a portion of hard bone. Once inside the bone, tension is applied to the anchor by sutures, causing the anchor to toggle such that it is no longer oriented in a direction parallel to the longitudinal axis of the bore, and the flared portion of the anchor engages and is wedged into the wall of the bore. The suture anchor is thus stabilized in an interference fit within the bore, and the detached tissue is thereby attached to the bone in the desired position.[0014]
• The term “suture needle” is used herein to encompass both conventional suture needles, used in open surgical procedures, as well as suture needles that may form a hollow, distal end of an elongate tool useful with closed surgical procedures.[0015]
• Further features of the invention, its nature and various advantages, will be more apparent from the accompanying drawings and the following detailed description of the drawings and the preferred embodiments.[0016]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of an exemplary suture anchor system of the invention;[0017]
• FIG. 2 is a cross-sectional view of a suture anchor attached to an inserter tool;[0018]
• FIG. 3 is a view of the first suture loop engaged with the suture anchor of FIG. 2;[0019]
• FIG. 4 is a partial view of a second suture loop with a suture loop closure;[0020]
• FIG. 5 is a partial view of the second suture loop and suture loop closure of FIG. 4 engaged with a suture needle;[0021]
• FIG. 6 is a view of a bore being drilled in hard bone for receiving a suture anchor system;[0022]
• FIG. 7 is a view of a portion of the suture anchor system engaged with a detached tissue;[0023]
• FIG. 8 is a view of the detached tissue with the second suture loop extending there through;[0024]
• FIG. 9 is a view of a portion of the suture anchor system before the suture anchor is inserted into a bone;[0025]
• FIG. 10 is a view of a portion of the suture anchor system showing the first suture loop being engaged by the suture anchor;[0026]
• FIG. 11 is a view of a portion of the suture anchor system with the suture anchor partially inserted into a bone;[0027]
• FIG. 12 is a view of a portion of the suture anchor system with the suture anchor fully inserted into a bone; and[0028]
• FIG. 13 is a view of a tissue attached to a bone, and a fully seated suture anchor, using the system and method of the invention.[0029]
DETAILED DESCRIPTION OF THE INVENTION
• Referring to FIG. 1, a[0030]system10 for anchoring tissue to bone in accordance with the invention is shown. The system includes asuture anchor12, afirst suture loop14 attached to thesuture anchor12, asuture needle16 and asecond suture loop18 attached to thesuture needle16. Thefirst suture loop14 and thesecond suture loop18 are interlocked with each other. The system may also include ananchor inserter tool20.
• The[0031]suture anchor12 has a first, leadingend22 and a second, trailingend24. The first, leadingend22 tapers, while the second trailingend24 flares out at one side, rendering the suture anchor asymmetrical in a plane that includes the longitudinal axis11. In the exemplary embodiment shown in FIG. 1, thesuture anchor12 has two flat,opposed sides26,28 between the first and second ends22,24 to allow for suture thread to easily pass back and forth. Althoughsides26,28 are shown as flat, it is understood that they may be otherwise shaped or contoured. For example, they may be curved or rounded. Thesides17,19adjacent sides26,28 may be curved, rounded, or flat.
• The[0032]exemplary suture anchor12 additionally comprises a suture thread-engaginggroove23 at thefirst end22 for seating portions of the first loop ofsuture thread14. The second, trailingend24 includes a flaredportion25, which is integral withside17. As shown in FIG. 1, flaredportion25 is located between the two opposedflat sides26,28, but it could be located anywhere on the suture anchor. Flaredportion25 may include a sharp edge for penetrating into hard bone, such as cortical bone. Flaredportion25 may also include a knife-like edge (not shown) with a rounded proximal end to promote bone penetration. Additionally,suture anchor12 may include surface features (not shown) to promote secure seating within bone and to prevent theanchor12 from backing out of the bone once inserted.
• As noted, the flared[0033]portion25 preferably is formed only on one side of thesuture anchor12. The flared portion results from a gradual widening of one side of the anchor. At its maximum dimension, the flared portion causes the suture anchor to be about 0.5 to 1.5 mm, preferably 1.0 mm, wider than it would be without the flared portion. As shown in FIG. 1, the flaredportion25 has a breadth dimension (B) that is consistent with the breadth ofside17, with which it is integral. The breadth (B) of the flaredportion25 is preferably about 0.3 to 1 mm.
• The[0034]suture anchor12 may be constructed from suitable metals or polymers known to those of ordinary skill in the art. In a preferred embodiment,suture anchor12 is fully bioabsorbable and is constructed from a bioabsorbable material such as polylactic acid (PLA) and polysulfone. Thesuture anchor12 should have a length sufficient to enable it to properly seat within bone. In an exemplary embodiment, theanchor12 is about 5 to 15 mm long, with the first, leadingend22 having at its narrowest portion a diameter of about 1 to 3 mm, a middle portion having a diameter of about 2 to 4 mm, and a second, trailing end having at its widest portion a diameter of about 2.5 to 5 mm. In one embodiment, theanchor12 is about 9 mm long with a leading end diameter of about 2 mm, an intermediate diameter of about 3 mm, and a diameter at the widest portion of the trailing end of about 4 mm. The suture thread-engaginggroove23 can have a depth of about 1 to 2.5 mm and an inner diameter of about 0.5 to 1 mm.
• The[0035]first suture loop14 may be suitably attached to thesuture anchor12 through a hole or holes provided in the body of thesuture anchor12 or by a suture retaining slot formed within the body of thesuture anchor12. In theexemplary suture anchor12, thefirst suture loop14 is attached at a location substantially intermediate the first22 and second ends24 of thesuture anchor12, and portions offirst suture loop14 extend past thesecond end24 onopposed sides26,28 of thesuture anchor12.
• In an additional embodiment, the[0036]first suture loop14 may be attached to thesuture anchor12 as illustrated in FIG. 3. Thefirst suture loop14 is formed from a length of suture thread by tying the two free ends of the thread into aknot30. It will be understood that other methods of attaching the two free ends, including the use of suture loop closure devices as further described below with regard to the second suture loop, may be used.
• As shown in FIGS. 2 and 3, the[0037]suture anchor12 includes a through-hole32 intermediate the first22 and second ends24. The through-hole32 is adapted, by providing varying diameters within the through-hole32, to retain thefirst suture loop14. In an exemplary embodiment, the diameter within the through-hole32 is varied by providing anannular collar34 therein. The inner diameter of theannular collar34 is large enough to allow the unknotted portion of thefirst suture loop14 to pass therethrough. The inner diameter of theannular collar34 is small enough, however, to prevent theknot30 from passing through the through-hole32. When the unknotted portion of thefirst suture loop14 is drawn through the through-hole32, as illustrated in FIG. 3, theknot30 is retained by theannular collar34 and thefirst suture loop14 is thereby attached to thesuture anchor12.
• As can further be seen by reference to FIG. 2, the[0038]second end24 of thesuture anchor12 may be provided with a mating feature for mating thesuture anchor12 to theanchor insertion tool20. As illustrated,anchor insertion tool20 has a threadedinsertion tip36 that engages a threadedbore38 formed in thesecond end24 of thesuture anchor12. Other configurations may be used as required.
• The[0039]first suture loop14 may be constructed from thread suitable for use as a suture. A variety of suture materials are well known to those of ordinary skill in the art. Exemplary materials include braided polyester and polydioxanone (PDS).
• The length of the[0040]first suture loop14 may be determined by a person of ordinary skill in the art depending upon the specific application desired for the system. This dimension depends, to a large extent, upon the dimensions of the tissue to be attached, the type of surgery to be performed, and whether an open or closed surgical technique is to be used. By way of example, the length of the first suture loop may range from about one quarter to one and one half inches in procedures to repair a Bankart lesion or a rotator cuff tear. In an exemplary embodiment as used in the method described hereinbelow, the length of thefirst suture loop14 is about 0.25 to 2 inches. Referring again to FIG. 1, thesuture needle16 has a first,tissue penetrating end40 and a second trailingend42. The size and shape of the needle used with the system of the invention may be selected by a person of ordinary skill in the art depending upon the specific application of the system, and in particular, depending upon whether the system is used in an open or closed (e.g., arthroscopic) surgical procedure. Generally,needle16 is at least slightly curved.
• In the exemplary embodiment of FIG. 1, which is typically used in open surgical procedures, the[0041]second suture loop18 is attached to thesuture needle16 at thesecond end42 ofneedle16. One of ordinary skill in the art will appreciate that a number of techniques can be utilized to join thesecond suture loop18 to thesuture needle16. For example, thesecond end42 of thesuture needle16 can be hollowed so that two free ends of suture thread may be inserted therein. The hollowed end is then crimped to securely retain the two ends of suture thread within thesecond end42 of theneedle16, thus creating thesecond suture loop18.
• In an alternative embodiment, shown in FIGS. 4 and 5, that is particularly suited for use in closed surgical procedures the[0042]second suture loop18 may be attached to theneedle16aby means of asuture loop closure44. Referring now to FIG. 4, thesecond suture loop18 may be formed by securing two free ends of a length of suture thread within asuture loop closure44. Thesuture loop closure44 may consist of a metal tube having an internal diameter large enough to admit two ends of suture thread. The two free ends of the suture thread are then entered into thesuture loop closure44 and thesuture loop closure44 is crimped to retain the ends of the suture thread and form thesecond suture loop18. It will be understood that thesuture loop closure40 may take other forms, including a knot tied with the two free ends of the suture thread. Asecond suture loop18, having asuture loop closure44, may be attached to asuture needle16aas shown in FIG. 5. In this exemplary embodiment, thesuture needle16ais a hollow member, having an opendistal end40, one wall of which includes a tissue-penetrating edge orpoint41. Aslot46 is formed in the wall of the distal end of the needle, preferably oppositepoint41. Theslot46 has anopen end43 that communicates with the opendistal end40 of thesuture needle16aand an opposite,closed end45. Theslot46 is wide enough to slidably engage thesecond suture loop18, but narrow enough to retain thesuture loop closure44 on one side of theslot46. Thesecond suture loop18 is then attached to thesuture needle16aby placing thesuture loop closure44 inside the openfirst end40 of thehollow suture needle16aand sliding thesuture loop closure44 and the attachedsecond suture loop18 within theslot46 to the closed end thereof.
• The[0043]hollow suture needle16aof FIG. 5 may also include an internally disposedactuator48. Theactuator48 may be a rod that is selectively slidable within thehollow suture needle16abetween a first position, in which theactuator48 is inside thehollow needle16aand does not reach theslot46, and a second position (not shown), in which theactuator48 extends past theslot46. Selectively sliding the actuator48 from the first position to the second position causes theactuator48 to contact the suture loop closure44 (and the attached second suture loop18), causingclosure44 to slide the length ofslot46 and become disengaged from theneedle16.
• [0044]Suture needle16a,as noted above, is well suited for use in closed surgical procedures. Thesuture needle16amay form the distal end of an elongate suture inserter tool (e.g., an arthroscopic, laparoscopic or endoscopic tool) that is useful in closed surgical procedures. Thesecond suture loop18, like thefirst suture loop14, may be constructed from well known materials suitable for use as a suture. The length of the second suture loop may be determined by a person of ordinary skill in the art depending upon factors such as the dimensions of the tissue to be attached, the type of surgery to be performed, and whether an open or closed surgical technique is to be used. For example, the length ofsecond loop18 is generally in the range of about 20 to 40 inches, and more preferably about 30 to 36 inches for closed surgical procedures. Open surgical procedures can utilize a smaller length forsecond loop18, in the range of about 6 to 40 inches and more preferably 8 to 10 inches.
• It is understood that various anchor insertion tools may be used with the system of the present invention. FIG. 2 illustrates an[0045]exemplary insertion tool20, thedistal end50 of which includes aninsertion tip36 that is threadably mated with thesecond end24 of thesuture anchor12. In some embodiments, thesuture anchor12 may be removably premated to the distal end of the insertion tool.
• The system of the invention for anchoring tissue to bone may be used in the method described herein below. For purposes of illustration, FIGS.[0046]6-13 depict the method in the context of arthroscopic shoulder repair, more specifically, attaching a detached labrum (as might result from a Bankart lesion or rotator cuff tear) to the glenoid rim of a scapula. It will be understood, however, that the system and method described herein are equally applicable to connecting detached tissue in other contexts as well.
• Referring to FIG. 6, a[0047]bore52 is formed in abone54. The diameter of thebore52 should be slightly smaller than the widest portion of the second, trailingend24 of thesuture anchor12. In an exemplary embodiment, the diameter of thebore52 is approximately 3 mm when the widest part of the suture anchor is about 4 mm. The length of the bore must be of sufficient length to allow for complete seating of the anchor, and to enable the depth of the anchor to be adjusted to help control the tightness of thefirst suture loop14. The actual length of thebore52 will depend upon the length of thefirst suture loop14 and the thickness of thedetached tissue56.
• As shown in FIG. 7, the[0048]suture needle16 is then passed through thedetached tissue56. Thesuture needle16 and the attachedsecond suture loop18 are pulled through thedetached tissue56 to advance the interlockedfirst loop14 through the tissue, as illustrated in FIG. 8. If the procedure is being performed arthroscopically, thesuture needle16aand the tool with which it is associated will be pulled from, and exit through, an exit portal (not shown).
• Alternatively, in embodiments that utilize the[0049]needle16a,shown in FIG. 5, theneedle16amay penetrate thedetached tissue56. Theactuator48 is then selectively moved so as to disengage thesuture loop closure44 and the attachedsecond suture loop18 from theneedle16a.Thesuture needle16amay then be withdrawn from the patient's body from the portal through which the needle entered. A suture grasper or retrograder (not shown) may be used to pull the remaining portion of thesecond loop18 through thedetached tissue56.
• In FIG. 9, the[0050]first suture loop14 is positioned over thebore52 by manipulating the position of thesecond suture loop18. When thefirst suture loop14 is in its desired position, theinsertion tool20 is maneuvered so that a portion of thefirst suture loop14 is seated in the suture thread-engaginggroove23 ofsuture anchor12, as shown in FIG. 10. Once thefirst suture loop14 is seated, theanchor10 is aligned with thebore52. By applying force to theinsertion tool20, thesuture anchor12 is forcibly urged into thebore52.Suture anchor12 can be tapped into thebore52, or it can be positioned in another manner. In the case of polymeric suture anchors12, because the diameter of thebore52 is slightly smaller than the widest part of thesuture anchor12, some of the polymeric material forming thesuture anchor12 may be scraped off during the insertion step to allow thesuture anchor12 to pass through the opening of thebore52. When thesuture anchor12 is partially inserted, as illustrated in FIG. 11, thesecond suture loop18 can be cut and discarded along with thesuture needle16.
• Referring to FIG. 12, when the[0051]suture anchor12 is advanced into thebore52, there will be a tight interference fit between thebore52 and theanchor12. By compressing and manipulating theanchor12 using theinsertion tool20, the surgeon can wedge the flaredportion25 of theanchor12 into the bone tissue within thebore52. Further, when tension is applied to theanchor12, the asymmetrical shape will cause a toggling of the anchor, resulting in theanchor12 becoming lodged within thebone54. As shown in FIG. 12,insertion tool20 can include a flexible neck, orportion21 that allows the tool to bend when pressure is exerted. This enables a compressive force to be greater on one side of the anchor, resulting in toggling or rotating the anchor. FIG. 13 shows thesuture anchor12 wedged inside thebore52, resulting in a snug, anatomically correct attachment of thedetached tissue56 to thebone54. Once theanchor10 is inserted intobore52, theinsertion tool20 may be removed.
• It will be understood that the foregoing is only illustrative of the principles of the invention, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. All references cited herein are expressly incorporated by reference in their entirety.[0052]

Claims (20)

What is claimed is:

1. A system for anchoring tissue to bone, comprising:

a suture anchor having a longitudinal axis, a first leading end and a second, trailing end, the second end having a flared portion that renders the suture anchor asymmetrical in a plane that includes the longitudinal axis;

a first loop of suture thread attached to the suture anchor;

a second loop of suture thread attached to the first loop, wherein the first loop and the second loop are interlocked with one another; and

a suture needle having a first, tissue penetrating end and a second, trailing end, wherein the suture needle is attached to the second loop.

2. The system ofclaim 1, wherein the suture anchor includes two substantially flat, opposed sides between the first end and the second end.

3. The system ofclaim 1, wherein a threaded bore is formed in the suture anchor, extending therein from the second, trailing end.

4. The system ofclaim 3, further comprising a suture anchor insertion tool, the tool being in the form of an elongate member having a proximal, handle end and a distal end.

5. The system ofclaim 4, wherein the distal end of the insertion tool includes an externally threaded insertion tip for engaging the threaded bore of the suture anchor.

6. The system ofclaim 5, wherein the insertion tool further includes a flexible portion that allows the tool to bend.

7. The system ofclaim 1, wherein a suture thread-engaging groove is formed in the first end of the suture anchor.

8. The system ofclaim 7, wherein the groove is about 1 to 2.5 mm in depth and has an inner diameter of about 0.5 to 1 mm.

9. The system ofclaim 1, wherein the flared portion has a shape effective to penetrate into hard cortical bone.

10. The system ofclaim 9, wherein the flared portion is a chamfered flare.

11. The system ofclaim 9, wherein the flared portion includes a sharp edge.

12. The system ofclaim 9, wherein the flared portion includes a knife edge with a flat proximal end.

13. The system ofclaim 1, wherein the second end is about 2.5 to 5 mm at its widest portion.

14. The system ofclaim 1, wherein the second loop comprises a suture loop closure and a length of suture thread having two free ends, the two free ends being attached to and secured within the suture loop closure.

15. The system ofclaim 1, wherein the second loop is attached to the second end of the suture needle.

16. The system ofclaim 1, wherein the second loop is attached to the suture needle by securing two free ends of suture thread within a hollow formed within the second end thereof.

17. The system ofclaim 1, wherein the length of the first loop is in the range of about 0.25 to 2 inches.

18. The system ofclaim 1, wherein the length of the second loop is in the range of about 6 to 40 inches.

19. The system ofclaim 1, wherein the first loop comprises a length of suture thread having two ends, the two ends being attached to each other by a suture loop closure.

20. The system ofclaim 1, wherein the suture anchor has a hole, extending transverse to the longitudinal axis, having an inner diameter adapted to allow the first loop to pass through the hole while preventing the suture loop closure from passing through the hole.

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