Bone anchor suture-loading system, method and apparatus

[0001] This invention pertains to a bone anchor suture-loading system, in particular a system, method and apparatus for automatically threading, knotting and trimming a suture onto a bone anchor, and the use thereof.

[0002] Connective tissue such as ligaments and tendons can tear and detach from the bone and muscle to cause pain and disability. One such tissue is the acetabular labrum in the shoulder which, if torn from its associated bone or muscle, will cause pain and inability to elevate and rotate the arm. Complete separation of the tissue from the bone or muscle can occur if the body is subjected to gross trauma, but the separation can also start from a small lesion on the tissue, the bone or muscle due to aging and other factors.

[0003] A detached connective tissue can surgically be reattached to the bone and muscle by an “open” procedure that involves making an incision into the body and reconnecting tissue to the bone and muscle. In one such procedure, the muscle is completely detached from the tissue and bone and the bone is debrided to match the edge of tissue at the tissue/bone reattachment location. The bone is also abraded or notched at the reattachment location to expedite healing. To reattach the tissue to the bone, a series of small diameter holes referred to as transosseous tunnels are punched through the bone over a distance of about 2 cm to 3 cm on the bone. One end of the suture is attached to the muscle and the other end is attached to the bone by threading the suture through the transosseous tunnels and tying the suture to intact bone between two successive tunnels; thereafter, the incision is closed.

[0004] As used herein the portion of the suture attached to the tissue or bone is referred to as the “standing end”; the end that extends towards the handler, or is manipulated by the handler, is referred to as the “working end”; the distal end of the implant or suture is that portion located away from the handler; and the proximal end is located next to or near the handler.

[0005] As will be appreciated, because the open procedure detaches the muscle and abrades the bone, the patient may experience discomfort and a relatively long recovery time.

[0006] In an alternative procedure that reduces trauma to the patient, the reattachment is done arthroscopically. In an arthroscopic procedure the surgeon reconnects the tissue to the bone by working through a small trocar portal into the body to reattach the tissue. In one arthroscopic procedure, rather than using transosseous tunnels to thread the suture through the bone, which is difficult to achieve arthroscopically, the tissue is connected to the bone by attaching one end of the suture to the tissue, securing the other end of the suture in a bone anchor, and embedding the anchor in the bone at the appropriate location thereby reattaching the tissue to the bone.

[0007] Although arthroscopic procedures are less invasive than open procedures, an arthroscopic procedure is not always the procedure used. One reason is that arthroscopic suturing of the tissue requires a high level of skill not possessed by all surgeons. Also, arthroscopic suturing of the tissue is clumsy and time consuming and only the simplest stitch patterns can be utilized. Additionally, tying a suture knot arthroscopically is challenging because it is difficult to judge the tightness of the suture. Also, the tension on the suture is not easily adjustable arthroscopically once the knot is formed. Further, in arthroscopic suturing, the knot required to tie the tissue may end up on top of the tissue in the form of a knot bundle, which is undesirable because of the potential for postoperative irritation when the muscle is exercised.

[0008] U.S. patent application Ser. No. 10/942,275 by Fallin et al. (“Fallin”) discloses a line lock threading system useable for selectively adjusting and/or tying off a line using a line lock. The system includes a cartridge that includes a retention feature shaped to retain the line lock. The line lock comprises a body that bounds a plurality of passageways through which the line is treaded. The system also includes a treading feature shaped to facilitate insertion of the line through the passageways of the line lock.

[0009] U.S. Pat. No. 6,652,561 to Tran (“Tran”) assigned to the present applicant and hereby incorporated by reference herein for all purposes discloses an embeddable bone anchor that eliminates the need to tie a knot on the tissue, while allowing for adjusting the tension on the suture and the tissue. The suture is threaded through holes in the anchor such that on pulling on the suture, the suture and tissue are locked to the anchor without a knot on the tissue. A deployable structure on the anchor embeds the anchor body in the bone and resist pullout.

[0010] Co-pending U.S. patent application Ser. No. 11/375,691 by Forester et. al (“Forester et. al”), assigned to the present applicant and incorporated herein by reference for all purposes, discloses a suture lock and bone anchor that cinches the suture and tissue to the anchor without a knot on the tissue. As is illustrated in FIGS. 1 and 2 herein, a suture loop (12) is formed on the anchor (10) by fastening a first leg (12a) of the suture onto the distal end of the anchor, and threading the tail (16) of the suture through a plurality of holes (14a, 14b, 14c) in the anchor to form a second suture leg (12b) on the anchor. On pulling on the tail or working end of the suture (16), the suture tightens on the anchor to cinch the loop (12) and tissue (18) to the anchor, without a knot on the tissue. When the anchor (10) is embedded in the bone (20) the fixed leg (12a), which is the standing end of the suture, is positioned distally on the anchor. Barbs (24) on the anchor assist in embedding the anchor and resisting pullout from the bone.

[0011] In procedures for reconnecting tissue to bone using anchors, there is a continuing need for systems to improve the threading of sutures to the anchors, and which avoid tying knots on the tissue. It is therefore and objective of the present invention to address these needs.

[0012] The present suture-loading system in one embodiment comprises: a bone anchor comprising a suture leg-anchoring structure and a plurality of body holes; a suture comprising a standing end portion and a working end portion; a standing end trackway to guide the standing end portion of the suture through the suture leg-anchoring structure; and a working end trackway to guide the working end portion of the suture through the body holes.

[0013] The present method of loading a suture onto a bone anchor in one embodiment comprises: snaring a standing end portion and a working end portion of a suture into a suture loader comprising a bone anchor, a suture standing end trackway, and a suture working end trackway; pulling the standing end portion of the suture through a suture leg-anchoring structure on the bone anchor along the suture standing end trackway; and pulling the working end portion of the suture through a plurality of holes on the bone anchor along the working end trackway.

[0014] The present suture loader apparatus for loading a suture on a bone anchor in one embodiment comprises: an anchor cradle adapted to receive a bone anchor; a suture trackway oriented to tie a suture knot on the bone anchor in the bone anchor cradle.

[0015] The present method of embedding tissue to bone in one embodiment comprises: suturing the tissue to obtain a standing end portion and a working end portion of suture; pulling the standing end portion along a first suture trackway in a suture loader apparatus to form a first suture knot on a bone anchor disposed in the suture loader apparatus; pulling the working end portion of the suture along a second suture trackway in the suture loader apparatus to cinch the suture on the anchor; and deploying the anchor in the bone.

[0016] Details of various embodiments of the present method, system and apparatus are illustrated and described the following Figures and specifications.

[0026] The present suture-loading system, method and apparatus are illustrated in FIGS. 1-9. In particular, an embodiment of a bone anchor loaded with a suture in accordance with the present method and system is illustrated in FIG. 5. A cross-section of the loaded anchor is illustrated in FIG. 1. The use of the loaded anchor to reattach tissue to the bone is illustrated in FIG. 2. Snare-wires attached to the suture and loaded into trackways to pull and guide the suture through the loader are illustrated in FIGS. 3, 4, 6 and 7. Algorithms of methods of loading the suture on to the anchor, and for embedding the tissue in a bone are illustrated in FIGS. 8-9.

[0027] With reference to FIGS. 1-7, the present bone anchor suture-loading system (30) comprises several components that cooperate to load and cinch the suture to the anchor. The components include: (i) a bone anchor (10) through which holes are formed to thread, knot and cinch the suture to the anchor; (ii) embedding structural features (24) on the bone anchor to facilitate embedding the anchor in the bone; (iii) a suture (12) comprising a standing end portion (34) and a working end portion (36) for securing soft tissue to the anchor; (iv) a suture standing end trackway (38) pre-loaded with a snare-wire (42b) to snare and pull the standing end portion of the suture through the anchor to form a knot (56) on the suture against the anchor; and (iv) a suture working end trackway (40) pre-loaded with a snare-wire (42a) to snare and pull the working end of the suture through the anchor to form a cinch point (52) on the anchor.

[0028] Optionally the system includes a pull-ring (46) to aid in pulling the snare wire (42) and standing end of the suture (34) through the standing end trackway (38); a suture reel (44) to aid in pulling the snare wire (43) and the working end of suture (36) through the working end trackway (40); and a cutting element or blade (54) to trim excess suture and cut the suture from the snare wires after the suture is threaded in the trackways (38, 40). In various embodiments the system is housed on a base (48) with a detachable lid (49) covering the base, and all the components can be formed from plastics and metal parts. Preferred materials include polycarbonates, nylon, zytel, and similar plastics. An overall size of the base and the lid is approximately 2 inches×2 inches×⅜ inches thick, however the size can be modified as needed to accommodate different anchors and the suture pattern desired on the anchor.

[0029] With reference to FIG. 1, an anchor that illustrates the use of the present suture loading system is described in co-pending U.S. patent application Ser. No. 11/375,691 by Forester et. al, herein incorporated by reference. In one embodiment the anchor (10) comprises: a body structure (13) having a plurality of body holes (14a, 14b, 14c) adapted to thread the working end of the suture (12, 16) through the anchor to form a cinch point (52), and the standing end of the suture to form a knot (56) on the distal end of the anchor (10); a suture leg-anchoring structure (32) adapted to fasten the standing end of the suture (12a, 34) onto the anchor; and a bone embedding structure (24) adapted to embed the anchor in the bone (20).

[0030] With reference to FIG. 1, the body holes (14a, 14b, 14c) extend through the anchor and are offset from each other relative to the longitudinal axis of the anchor to facilitate forming cinch point (52) on the working end of the suture against the anchor. As is illustrated in FIG. 1, the surface on the anchor under the cinch point (52) is flattened (17) to seat and reduce the profile of the cinch on the anchor. The diameter of the body holes is sized to accommodate one or more strands of suture.

[0031] With reference to FIG. 1, a suture leg-anchoring hole (54) that extends through the suture leg-anchoring structure (32) allows for passing the standing end of the suture (34) through the distal end of the anchor to fasten the suture to the anchor by a retaining knot (56). To ensure that the suture knot (56) is securely attached over the suture-anchoring hole, the cross-section of the knot (56) is made larger than the cross-section of the suture-anchoring hole. As will be appreciated by one ordinarily skilled in the art, the standing end of the suture can also be retained on the suture leg-anchoring structure by attaching the suture onto a structure disposed outside of the sure anchoring hole.

[0032] With reference to FIGS. 1 and 2, to facilitate retaining the anchor in bone the anchor is provided with a bone-embedding structure (24) located proximal to the suture leg-anchoring structure (32). In one embodiment the bone-embedding structure (24) comprises a plurality of barbs oriented towards the distal end of the anchor. As is illustrated in FIGS. 1 and 2, the barbed structures taper towards the distal end of the anchor to resist proximal pullout of the anchor from the bone (20).

[0033] With reference to FIGS. 3-6, the present suture standing end trackway (38) in one configuration comprises removable pins (38a, and 38b) located in the base (48) such that a pre-threaded snare-wire (42) can be configured around and through the pins into a pattern that can be transferred to the suture by snaring and pulling the suture through the trackway (38) and removing the pins. In a particular embodiment illustrated in FIGS. 4 and 5, the snare wire is pre-configured into a figure-8 pattern that becomes a figure-8 knot (56) on the suture when the pins are removed. The knot (56) is tightened by pulling on the suture both sides of the knot. In one embodiment, the distal end of the suture is attached to pull-ring (46) to tighten the knot. After the knot is tightened excess suture is trimmed by routing the suture over the cutting blade (54).

[0034] With reference to FIG. 3-6, the present suture working end trackway (40) in one configuration comprises posts (40a, 40b, 40c) located in the base (48) such that a pre-threaded snare-wire (43) can be configured around the posts into a pattern that can be transferred to the suture by snaring and pulling the suture through body holes (14a, 14b, 14c) in the anchor (10) and through the trackway (40). In an embodiment illustrated in FIGS. 4 and 5, the snare wire is pre-configured into two intertwined loops (43a and 43b) that will form a cinched point (52) when the anchor is removed form the anchor cradle (68) and the working end of the suture (36) is tensioned. In one embodiment, the proximal end of the suture is attached to suture reel (44) that can be operated to gradually cinch the suture on the anchor (10) and fix the size of the loop (12). As will be appreciated by one ordinarily skilled in the art, to cinch the tissue to the anchor on the loop, the suture is attached to the tissue before the standing and working ends of the suture are snared into the trackways (38, 40) by the pull-ring (46) and the suture reel (44). As is illustrated in FIG. 3, each of the snare wires (42, 43) comprise a loop (42a, 43c) at the end of the snare wire to snag the working end (36) and standing end (34) of the suture. In one embodiment the loops (42a, 43c) are stretched open to snag the ends of the suture (12a, 12b) by looping the ends concentrically around a pair of holes (42b, 43c) in the base (48). In one embodiment as illustrated in FIG. 2-4 the suture reel (44) comprises a handle (17) useable to guide the loaded anchor into hole (25) in the bone (20) to embed the anchor (10) and tissue (18) in the bone. After inserting the anchor in the hole (20) as is illustrated in FIG. 2, excess suture tail (16) can be is cutoff by the surgeon. In various embodiments the present suture loading system is useable to load a suture including braided and monofilament sutures.

[0035] With reference to FIG. 8, the present suture loading system can be used to load a suture onto a bone anchor by a series of steps, as follows: (82) snaring a standing end portion (34) and a working end portion (36) of the suture (12) into a suture loader (30) comprising: a bone anchor (10), a suture standing end trackway (38), and a suture working end trackway (40); (84) pulling the standing end portion of the suture through a suture leg-anchoring structure (32) on the bone anchor (10) along the suture standing end trackway (38); and (86) pulling the working end portion (36) of the suture through a plurality of holes (14a, 14b, 14c) on the bone anchor along the working end trackway (40). These steps can be implemented as described above on the present apparatus and system.

[0036] With reference to FIG. 9, the present suture loading system can be used for embedding tissue to bone by a series of steps, as follows: (92) suturing the tissue to obtain a standing end portion and a working end portion of suture; (94) pulling the standing end portion along a first suture trackway in a suture loader apparatus to form a first suture knot on a bone anchor disposed in the suture loader apparatus; (96) pulling the working end portion of the suture along a second suture trackway in the suture loader apparatus to cinch the suture on the anchor; and (98) deploying the anchor in the bone. These steps can be implemented as described above on the present apparatus and system.

[0037] Accordingly, as illustrated for example in FIG. 5, with the present system and method a suture can be loaded onto an anchor (10) such that a knot (56) is formed on the standing end of the suture (32), while the working end of the suture is cinched (52) to form a loop (12) attached to a tissue (18). Excess lengths of suture can be trimmed off after the anchor is loaded, and the loaded anchor removed from the system by separating the lid (49) from the base (48), without entangling the suture. Thus loaded, the anchor can be imbedded an a bone to reattach a connective tissue.

[0038] By the present description and Figures it is to be understood that the terms used herein are descriptive rather than limiting, and that changes, modifications, and substitutions may be made without departing from the scope of the invention. Therefore the invention is not limited to the embodiments described herein, but is defined by the scope of the appended claims.