Tissue Engagement Device and Method

Abstract

Disclosed is a soft tissue engagement device. The soft tissue engagement device includes a substantially rigid elongate body extending from a first end to a second end. The elongate body is configured to be inserted at least partially within the soft tissue, transverse to a load-bearing direction of the tissue. The elongate body is further configured to engage sutures attached to underlying suture-anchors secured to a bone, thereby to draw the soft tissue onto the bone. Also disclosed is a method for attaching soft tissue to a bone.

Claims

1. A soft tissue engagement device comprising a substantially rigid elongate body extending from a first end to a second end, the elongate body configured to be inserted at least partially within the soft tissue, transverse to a load-bearing direction of the tissue and configured to engage sutures attached to underlying suture-anchors secured to a bone, thereby to draw the soft tissue onto the bone.

2. The soft tissue engagement device of claim 1, wherein the elongate body is resiliently flexible.

3. The soft tissue engagement device of claim 1, wherein a cross section of the elongate body is substantially uniform along its length.

4. The soft tissue engagement device of claim 1, wherein the elongate body comprises areas of relatively greater cross-sectional diameter.

5. The soft tissue engagement device of claim 1, wherein the elongate body tapers along its length from one end to the other or tapers from a middle region towards the first and second ends.

6. The soft tissue engagement device of claim 1, wherein the elongate body comprises retention lugs at one or both of the first and second ends.

7. The soft tissue engagement device of claim 1, wherein the elongate body is substantially solid along its length.

8. The soft tissue engagement device of claim 1, wherein at least a length of the elongate body is hollow.

9. The soft tissue engagement device of claim 1, wherein a sidewall of the elongate body includes one or more apertures therein for receiving the sutures.

10. The soft tissue engagement device of claim 1, wherein the elongate body includes areas of roughened surface to provide a grip for the sutures.

11. The soft tissue engagement device of claim 1, wherein the elongate body includes one or more grooves to receive a suture.

12. The soft tissue engagement device of claim 1, wherein the elongate body includes sutures adjacent each end of the elongate body.

13. A method of attaching a soft tissue to a bone, the method comprising: inserting a soft tissue engagement device into the soft tissue transverse to a load bearing direction of the soft tissue, wherein the soft tissue engagement device comprises a substantially rigid elongate body extending from a first end to a second end, the elongate body configured to engage sutures attached to one or more suture-anchors secured to a bone; passing sutures from the suture-anchors through the soft tissue medially to the soft tissue engagement device; passing the sutures over the soft tissue engagement device; and subsequently, securing each of the sutures to a suture-anchor.

14. The method of claim 13, wherein the one or more suture-anchors are one or more medial anchors positioned inferiorly to the soft tissue engagement device in the underlying bone.

15. The method of claim 14, wherein sutures are passed from the one or more medial anchors through the soft tissue, medial to the tissue engagement device, over the device and secured back to the one or more medial anchors.

16. The method of claim 13, further including securing one or more lateral anchors to the bone.

17. The method of claim 16, wherein sutures are passed from the one or more medial anchors through the soft tissue, medial to the tissue engagement device, over the device and through the soft tissue lateral to the device and secured to the one or more lateral anchors.

18. The method of claim 17 including: fastening a first medial anchor to the bone; fastening a second medial anchor to the bone, spaced from the first medial anchor; fastening a first lateral anchor to the bone at a location lateral to the first and second medial anchors; fastening a second lateral anchor to the bone, spaced from the first lateral anchor; providing a first suture having a fixed end a free end, the fixed end secured to the first medial anchor and passing the free end through the soft tissue medial to the tissue engagement device, over the device and through the tissue lateral to the device and securing the free end to the first lateral anchor; and providing a second suture having a fixed end a free end, the fixed end secured to the second medial anchor and passing the free end through the soft tissue medial to the tissue engagement device, over the device and through the tissue lateral to the device and securing the free end to the second lateral anchor.

19. The method of claim 18, further including: providing a third suture having a fixed end a free end, the fixed end secured to the first medial anchor and passing the free end through the soft tissue medial to the tissue engagement device, over the device and through the tissue lateral to the device and securing the free end to the second lateral anchor; providing a fourth suture having a fixed end a free end, the fixed end secured to the second medial anchor and passing the free end through the soft tissue medial to the tissue engagement device, over the device and through the tissue lateral to the device and securing the free end to the first lateral anchor.

20. The method of claim 13, wherein the soft tissue is a tendon or a ligament.

21. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] By way of example only, embodiments are now described with reference to the accompanying drawings, in which:

[0057] FIGS. 1A and 1B show a top view of a tendon repair method of the prior art in an unloaded and loaded configuration, respectively;

[0058] FIGS. 2A and 2B show a side view of the tendon repair method of FIGS. 1A and 1B in an unloaded and loaded configuration, respectively;

[0059] FIGS. 3A and 3B show a top view of a tendon repair method using a soft tissue engagement device according to an embodiment of the present disclosure in an unloaded and loaded configuration, respectively;

[0060] FIGS. 4A and 4B show a side view of the tendon repair of FIGS. 3A and 3B in an unloaded and loaded configuration, respectively;

[0061] FIG. 5 shows soft tissue engagement devices according to several embodiments of the present disclosure;

[0062] FIGS. 6A to 6F show soft tissue engagement devices according to several further embodiments of the present disclosure;

[0063] FIGS. 7A-7F illustrate steps in a method of attaching a tendon to a bone according to one embodiment of the present disclosure;

[0064] FIG. 8 shows a perspective view of a completed tendon repair using the method of FIGS. 7A-7F;

[0065] FIG. 9 shows an enlarged cross-section of the repair of FIG. 7;

[0066] FIG. 10 shows a top view of a tendon repair according to another embodiment of the present disclosure;

[0067] FIG. 11 shows a side view of a tendon repair method according to another embodiment of the present disclosure;

[0068] FIG. 12 shows load-displacement curves obtained during cyclic load testing of tendon connections to bone according to two embodiments of the present disclosure, compared to a suture-only repair;

[0069] FIGS. 13A-13B show exemplary embodiments of the device of the present invention configured to be deformable to confirm when implanted;

[0070] FIGS. 14A-14C show exemplary embodiments of a guide which assists in alignment and placement for use in conjunction with the present invention;

DESCRIPTION OF THE INVENTION

[0071] A soft tissue engagement device of the present disclosure is generally shown as 100 in the drawings. The device may be used for tissue repair. For example, the device 100 may be used in reattaching of soft tissue to bone, or reattachments of severed ends of soft tissue to each other.

[0072] The examples refer primarily to repair of the rotator cuff tendon in which the tendon is reattached to bone. However, it should be understood that the device may be applicable in repair of any soft tissue, ligament or tendon or in tissue such as bone and in particular bones which are not weight bearing. As further examples, the device may be used in tendon to tendon repair, or tendon to bone repair, of rotator cuff tendon, Achilles tendon or patellar tendon. Further, the device may be used in reattachment of the ligament to bone, or ligament to ligament. For example, the device may be used in repair of the anterior cruciate ligament or posterior cruciate ligament. The invention is not limited to these specific applications and may be used in other procedures. Use of the disclosed device and method may improve resistance to suture cut-out or cheese wiring of the sutures through the tissue, thereby improving the tensile strength of the repair. Excessive micro-motion at the repair interface increases the challenge for the body to heal, resulting in increased loose connective tissue, and scar tissue formation that do not aid in function. The present device adds to the rigidity of the repair, reducing micro-motion at the interface, improving healing and function.

[0073] FIGS. 1A,1B, 2A and 2B show a tendon repair method of the prior art. The tendon 10 is secured to the bone 20 by sutures 40 which connect from a medial row of suture anchors 50 to a lateral row of suture anchors 60 in a suture bridge technique. However, upon application of force to the tendon 10 by muscle 30, the sutures 40 cut through the tendon 10 in a cheese wiring manner. The displacement of the sutures through the tendon 10 at points 11 and 12 is shown in FIGS. 1B and 2B. This displacement not only further damages the tendon 10 tissue, but also corresponds to a displacement of the lateral end 13 of the tendon 10 from its initial placement on the bone 20. This displacement of the lateral end 13 of the tendon 10 as a result of cheese wiring is non-recoverable and results in a loss of footprint between the tendon 10 and the bone 20. That is, the displacement results in a reduction in the available contact area between the tendon 10 and the bone 20 on which osseous integration is possible, reducing the efficacy of the repair. This failure injures the tendon and renders it with little mechanical integrity for salvage surgeries. The current invention also allows improved salvage properties following failure of a traditional suture bridge repair

[0074] FIGS. 3A, 3B, 4A and 4B show a similar tendon repair, using tissue engagement device 100 according to the present disclosure. The tissue engagement device 100 is inserted at least partially intratendinously, transverse to the load-bearing direction of the tendon 10. Sutures 201, 202, 203, 204 are secured to the bone 20 and passed through the tendon 10 at points 11 and 12, medial to the tissue engagement device 100. The sutures 201, 202, 203, 204 are then secured to the bone 20. FIG. 4A shows the path of suture 202 from a medial anchor 411 to a lateral anchor 421. FIGS. 3B and 4B show the response of the tendon repair construct under load. Unlike the construct of FIGS. 1B and 2B, the force acting on the tendon 10 from the muscle 30 is not concentrated at points 11 and 12. Rather, the tissue engagement device 100 engages the sutures at points 11 and 12 and distributes the force applied by the sutures 201, 202, 203, 204 on the tissue of the tendon 10 across a greater surface area. This distribution of force increases the resistance of the repair construct to suture cut-out or cheese wiring. Further, the use of a tissue engagement device according to the disclosure may decrease the time taken to perform a tissue repair operation by reducing the need for complex suture stitching techniques.

[0075] As shown in FIG. 4B, there may be some displacement of the lateral end 13 of the tendon 10 under load from its initial placement on the bone. However, in this instance, the displacement is primarily due to elastic deformation of the sutures 201, 202, 203, 204, rather than due to damage of the tissue of tendon 10 as shown in FIG. 2B. As such, the displacement is recoverable when the load is removed, and the contact footprint between the tendon 10 and the bone 20 is maintained.

[0076] FIG. 5 shows tissue engagement devices 100a-h according to several embodiments of the present disclosure. Each of the tissue engagement devices 100a-h is in the form of an elongate body extending from a first end 101 to a second end 102. The elongate body may be substantially straight, as in embodiments 100a-d and 100g, or may be curved or wavy as in embodiments 100e, 100f, and 100h.

[0077] In some embodiments, for example, as in devices 100a, 100b, 100c, 100d, 100e, the elongate body has a substantially circular cross-section. In other embodiments, for example as in devices 100f, 100g, 100h, the elongate body has an elliptical cross section. In other embodiments, other cross sectional shapes may be used.

[0078] In some embodiments, the elongate body may have a substantially constant cross section along its length (as in devices 100a, 100d, 100e, 100f, 100g and 100h). In other embodiments, the elongate body may have a cross section which varies along its length. One such example is shown in FIG. 100b, which includes a lug 110 at each of its first and second ends 101, 102. The lugs may be configured to substantially prevent slipping of the ends 101, 102 of the device 100b into the tissue. By contrast, embodiments without such lugs 110 may be configured to be wholly implantable in the tissue.

[0079] In some embodiments, for example as in device 100c, the device may comprise a side wall 120, defining an internal lumen 125. The lumen may be configured to received one or more sutures, wires, or a delivery device. Alternatively or additionally, the device may comprise one or more apertures which may extend wholly or partially through the device 100. For example, apertures 131, 132 of device 100c extend through the side wall 120 to the lumen 125. The suture may also be integral with the device or moulded into the device such that the suture is rigidly fixed and prevented from sliding therethrough.

[0080] Further embodiments of the device are provided in FIGS. 6A to 6F. In FIG. 6A, the device 100i comprises a central shaft 120 centrally extending through helical member 121. End 122a is pointed to aid in the insertion through tissue.

[0081] Device 100j comprises helical member 121 without the central shaft 120.

[0082] Device 100k comprises an elongate body 130 having opposed lugs 131a and 131b. Each lug has an aperture 132a and 132b which may be used to receive a suture.

[0083] In FIG. 6D, the device 100l has four spaced lugs 133 which are aligned. Device 100m of FIG. 6E has two lugs 134.

[0084] Lugs 134a and 134b of device 100n provide another embodiment. Lug 134a extends on either side of shaft 136 and has two apertures positioned on opposite sides of the shaft 136. Lug 134b is angled in shape and has one half extending in a plane orthogonal to the other half.

[0085] The elongate body of the soft tissue engagement device may be configured such that it is deformable to substantially conform to the underlying bone when implanted. Examples such embodiments are shown in FIGS. 13A and 13B.

[0086] The device 100p of FIG. 13A has a substantially straight elongate body. In this embodiment, the elongate body has a relatively high modulus of elasticity and is configured to deform to partially conform to the surface of the underlying bone 20, as shown in the lower portion of FIG. 13A. This results in a relatively low contact footprint area between the tendon 10 and the bone 20.

[0087] In other embodiments, for example devices 100q, 100r and 100s as shown in FIG. 13B, the elongate body has a lower modulus of elasticity and is configured to deform to conform to the curvature of the underlying bone under load. The initial configurations of the devices are shown at the top of FIG. 13B. Each of these devices conforms to the shape of the bone to take the final, implanted configuration as shown in the lower portion of FIG. 13B.

[0088] Device 100r is initially straight, as with device 100p. However, as device 100r is more flexible than device 100p, the final contact footprint area between the tendon and the bone in FIG. 13B is greater than in FIG. 13A.

[0089] Device 100s is curved to closely match the curvature of the bone such that minimal deformation is required to match the shape of the bone. Device 100q is over-contoured, that is, it has a curvature greater than that of the bone such that deformation is required to decrease the curvature of device 100q for conformation to the bone.

[0090] In one example, the tissue engagement device 100 may be used for repair of a detached rotator cuff tendon. The repair method may include steps as illustrated in FIGS. 7A to 7F. The surgery may be performed arthroscopically.

[0091] FIG. 7A shows the bone 20 and tendon 10 before the repair is commenced. In FIG. 7B, two medial anchors 411a, 411b are placed in the greater tuberosity of the bone 20. The tendon 10 is positioned over the bone 20 in a desired fixation location and sutures 201, 202, 203, 204 are passed from the medial anchors 411a, 411b through the tendon tissue, medial to the tissue engagement device 100, as shown in FIG. 7C.

[0092] The tissue engagement device 100 is then inserted intratendinously, lateral to the musculotendinous junction, such that an axis of the device 100 lies substantially orthogonal to an axis or loading direction of the rotator cuff tendon. In some embodiments, the tissue engagement device 100 may be inserted through a transverse incision in the tendon 10, or, in other embodiments, may be pushed through the tissue of the tendon without first making an incision. In other embodiments it is envisaged that the device may sit above the tendon on the bursal side or below the tendon on the articular side.

[0093] The sutures are then passed over the tissue engagement device 100 and secured to one or more anchors. FIG. 7E shows two lateral anchors 412a, 412b inserted in the bone 20, while FIG. 7F shows the sutures 201, 202, 203, 204 secured to the lateral anchors 412a, 412b to form a suture bridge. For illustrative purposes, the tendon 10 is shown as partially transparent in FIG. 7F, revealing the position of the tissue engagement device 100. However, in this embodiment, the device 100 is located wholly intratendinously.

[0094] In other embodiments, the tissue engagement device 100 may be woven through longitudinal fibres of the tendon 10. In some embodiments, the device 100 may be inserted to the tendon tissue such that it weaves in and out of the tendon tissue. As such, one or more portions of the device 100 may be extratendinous on the bursal side and/or the articular side of the tendon 10. In such embodiments, the extratendinous portions of the tissue engagement device 100 on the articular and/or the bursal side of the tendon 10 may be used as attachment points for sutures.

[0095] FIGS. 8 and 9 show the completed repair according to the method of FIGS. 7A-H. The sutures 201, 202, 203, 204 passed from the medial anchors 411a, 411b, through the tissue of tendon 10 medial to the tissue engagement device 100, and are secured lateral anchors 412a, 412b. The tissue engagement device 100 engages the sutures 201, 202, 203, 204 adjacent each of its ends.

[0096] In other embodiments, the sutures 201, 202, 203, 204 may be secured to a single lateral anchor 415. In other embodiments, more than two lateral anchors may be used.

[0097] In some embodiments, the medial anchors may be omitted. For example, as shown in FIG. 10, sutures 200 pass from lateral anchor 415 around the tissue engagement device 100 and are secured to the lateral anchor 415 (other embodiments may use more than one anchor). In other embodiments, the sutures may pass through a lumen or one or more apertures of the device 100 (for example, as shown in device 100c of FIG. 5). The omission of one or more anchors may reduce the overall cost of the repair procedure.

[0098] Alternatively, in some embodiments, lateral anchors may be omitted. For example, as shown in FIG. 11, suture 200 is passed from a medial anchor 400 through the tissue of tendon 10 and then secured to the medial anchor 400 such that the suture 200 encircles the tissue engagement device 100. In such embodiments, the suture length is significantly shortened compared to embodiments where the sutures are secured to a lateral row of anchors. This minimises potential migration of the tendon away from the attachment site due to elastic deformation of the sutures. In embodiments having one or more extratendinous portions of the tissue engagement device 100, sutures may be looped through extratendinous portions on the articular side of the tendon 10 and secured to medial anchors. This provides for improved rigidity of the connection between the tendon 10 and the bone 20 due to the shortened suture length.

[0099] However, where only a medial row of anchors is used, the lateral end 13 of the tendon 10 is left free and is not compressed onto the bone, as shown in FIG. 10. This may inhibit optimal healing. Accordingly, in some embodiments, an optional second set of sutures may pass from the medial anchors around the tissue engagement device and to a lateral anchor (or row of anchors) thereby to compress the lateral end of the tendon onto the bone. The demands of the second set of sutures in this configuration will be low as the majority of the load will be directed between the tendon, device and medial sutures/anchor(s).

[0100] In some embodiments, a guide 500 may be used to insert the soft tissue engagement device 100 and/or one or more anchors. FIGS. 14A to 14C illustrate an exemplary embodiment of a guide which assists in achieving alignment and proper placement of a soft tissue engagement device 100t with anchors 413a and 413b. In FIG. 14A, the device 100t is inserted through the tendon 10, transverse to the load bearing direction using arm 510. As shown in FIG. 14B, anchor 413a is subsequently placed using punch 520a, through the tendon 10 and through anchor receiving aperture 135a of the device 100t and into the bone 20. Anchor 413b is similarly placed, as shown in FIG. 14C, using punch 520b. It will be appreciated that, in this embodiment, the need for sutures is eliminated as the device 100t engages the anchors 413ab directly.

[0101] In some embodiments, one or more tissue engagement devices may be used to attach one severed end of a soft tissue structure to another severed end. For example, the device may be used to reattach ends of a severed tendon or ligament. In such embodiments, a first tissue engagement device may be inserted into the tissue of a first severed end of the tissue, while a second tissue engagement device may be inserted into a second severed end of the tissue. Sutures may then be passed through the tissue, around the tissue engagement devices and tied to form one or more loops, securing the severed ends of the tissue to each other. As with the soft-tissue to bone connection, the tissue engagement device may improve resistance to suture cut-out or cheese wiring of the sutures through the tissue and thereby improve the tensile strength of the repair.

[0102] FIG. 12 shows load-displacement curves for three tendon repairs subjected to cyclic loading of 5 to 50 N. Curve 510 corresponds to a control tendon repair, constructed using medial and lateral rows of bone anchors connected by a suture bridge. Curve 520 corresponds to a tendon repair constructed using a tissue engagement device according to the present disclosure, in combination with medial and lateral rows of bone anchors connected by a suture bridge (for example, as shown in FIGS. 8 and 9). Curve 530 corresponds to a to a tendon repair constructed using a tissue engagement device according to the present disclosure, in combination with a medial row of bone anchors only (for example, as shown in FIG. 11). Comparing, curves 520 and 530 to the control 510 shows that repairs constructed with the tissue engagement device of the present disclosure are more rigid than the control, and exhibit less creep over repeated cycles. The increase in creep in the control 510 is due to damage to the tendon as the sutures cheese wire through the tissue. Further, it is evident that the repair using medial anchors only (curve 530) is more rigid than the repair using both medial and lateral anchors, due to the reduced suture length.

[0103] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.