Tendon crimp for passage into a bone tunnel and method for use thereof

A surgical device and method is used in attaching a tendon or a ligament to bone. In a preferred form, the device is a crimp configured to reduce the thickness of the free end of the tendon or the ligament to facilitate insertion of the tendon or the ligament into an opening formed in the bone.

FIELD OF THE INVENTION

The present invention relates to improvements in the attachment of tissue structures to bone.

BACKGROUND OF THE INVENTION

In orthopaedic surgery there are many procedures that make use of a tendon or a ligament graft which is tunnelled into a bone tunnel. The goal is to reconstruct a ligament where no other option may work and where the surgeon needs to recreate a strong ligament/tendon interface as part of a procedure.

As shown inFIG. 1, those familiar in the art of orthopaedic surgery know that the task of passing a tendon or a ligament graft10into a bone20having a bone tunnel30can be a very frustrating experience. In most instances the graft to be tunnelized sustains significant damage in the process. It is often desirable to pass the thickest graft possible through the smallest tunnel, but even passage of a graft through a bone tunnel that is near equal in size is simply not practical and the surgeon has to settle for passing a significantly smaller graft through a larger tunnel to avoid the complications of the process.

The present invention seeks to lessen these problems by providing a device and method which allows a tissue structure such as a tendon or a ligament to be inserted into a bone tunnel without many of the disadvantages of conventional devices and methods.

SUMMARY

The device in one or more embodiments of the present invention includes a crimp that acts on the free end of the graft, usually a tendon or a ligament, to be inserted into the tunnel. Unless otherwise indicated, the present invention will be described for use with a tendon, though it will be appreciated that the invention is not so limited. For example, preferred embodiments of the present invention may be configured for use with other tissue structures or grafts such as ligaments. A crimper is utilized to compress the crimp in place. The crimp is applied to the free end of the tendon to compress the tendon and squeeze the fluid content and reduce the segment of tendon under the crimp. The leading end of the tendon is now optimized for passage into a bone tunnel.

The present invention in one preferred aspect provides for a method for inserting a free end of a tendon or a ligament into a bone. The method includes forming an opening in the bone; crimping a portion of the free end of the tendon or the ligament with a crimp; and inserting at least the crimped portion of the tendon or the ligament into the opening of the bone.

In another preferred aspect, the present invention provides for a method for inserting a free end of a tendon or a ligament into a bone. The method includes: forming an opening in the bone; enclosing a portion of the free end of the tendon or the ligament with a sleeve having a central longitudinal axis and a minimum cross-section perpendicular to the central longitudinal axis, the sleeve being biodegradable; reducing the minimum cross-section of the sleeve to crimp the portion of the free end of the tendon or the ligament; inserting the crimped portion of the tendon or the ligament into the opening of the bone; and permitting the sleeve to biodegrade so that the crimped portion of the tendon or the ligament expands within the opening.

In a further preferred aspect, the present invention provides for a surgical kit for attaching a tendon or a ligament to bone. The kit includes a crimp composed of a surgical grade material, the crimp having an interior surface and an exterior surface, the interior and exterior surfaces each having a plurality of surface projections. The kit also includes an insertion shield for placement in front of the crimp when the crimp is engaged with the tendon or the ligament, the insertion shield being configured to facilitate insertion of the crimp into an opening in the bone, the insertion shield having an insertion end, a trailing end, a length from the insertion end to the trailing end, a central longitudinal axis and a minimum cross-section perpendicular to the central longitudinal axis, the minimum cross-section decreasing along at least a portion of the length towards the leading end.

In yet a further aspect, the present invention provides for a sleeve for attaching a free end of tendon or ligament to bone. The sleeve includes a body having a first end, a second end, a length from the first end to the second end and a circumferential wall from the first end to the second end, the wall forming a passage from the first end to the second end, the passage having a central longitudinal axis and a minimum cross-section perpendicular to the central longitudinal axis. The sleeve includes a plurality of openings in the wall. The body of the sleeve is formed of a biodegradable material. The body of the sleeve is configured to reduce from a first minimum cross-section in which the free end of the tendon or the ligament may be inserted into the passage to a second minimum cross-section which traps at last a portion of the free end of the tendon or the ligament in the passage.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 2 to 5show a preferred embodiment of a crimp100, an insertion shield102and a suture104for engagement with a portion of a free end12of tendon10. In use, crimp100is crimped around a portion of suture104and free end12of tendon10. Insertion shield102is slid along suture104until it abuts free end12of tendon10. Free end12of tendon10is then pulled into the bone tunnel together with the assembly of crimp100and insertion shield102using suture104. The preferred elements of the device and their interrelationship are described below.

Referring toFIGS. 2 and 3, crimp100has a first end106, a second end108, a circumferential wall110, an interior surface112and an exterior surface114. Interior surface112of wall110forms a passage116from first end106to second end108. Wall110preferably has a pair of longitudinal edges118,120that form a slit or slot122. While in an uncontracted state, passage116is preferably sized and configured to accommodate the insertion of the free end of the tendon therein. After the tendon has been inserted at least part way into passage116, crimp100is crimped, reducing the minimum cross-section of passage116and compressing the tendon within crimp100as shown inFIG. 2.

Crimp100is preferably formed from a surgical grade material that is configured to be bent or crimped, preferably with a crimper. Examples of materials suitable for use with crimp100include, but are not limited to, metals such as titanium, stainless steel, and nitinol, and various non-metal materials and polymers.

A shown inFIGS. 4 and 5, insertion shield102includes an insertion end124, a trailing end126, an interior128, and a preferably frusto-conical, bullet-like tip130for smoother passage through the bone tunnel. Tip130preferably includes an aperture132sized and configured for the passage of suture104therethrough. In use, suture104can be placed into tendon10prior to the application of crimp100. Suture104passes through aperture132and the center of bullet tip130. A pull on suture will104provide the necessary traction to deliver the assembly through the bone tunnel. Insertion shield102preferably facilitates the insertion of the free end of the tendon into the bone tunnel by providing a ramped surface to minimize interference between the free end of the tendon and the bone tunnel during insertion of the free end into the bone tunnel. The interaction between insertion shield102, crimp100and suture104will be described in further detail below in relation to a preferred method in accordance with another preferred embodiment of the present invention.

Having described the preferred components of the device, a preferred method of use will now be described with reference toFIGS. 6 to 11. Referring toFIG. 6, suture104is inserted into free end12of tendon10, preferably by looping the suture through and around fibers14of tendon10. As shown inFIG. 7, crimp100is placed around a portion of free end12, and then crimped. The free end of tendon10may be inserted into second end108and through passage116of crimp100. Alternatively, slit122may have a distance between longitudinal edges118,120sufficient to permit the thickness of tendon10therethrough so that the tendon is inserted into passage116laterally through slit122. Once tendon10is in passage116, crimp100is preferably crimped using a crimper. The crimping of crimp100preferably compresses free end12of tendon10, squeezing the fluid content from the portion being crimped and reducing the thickness of free end12. The compression also enhances the securing of suture104to free end12of tendon10.

FIG. 8shows the engagement of insertion shield102with suture104and crimp100. The ends of suture104are inserted through trailing end126and aperture132of insertion shield102. Insertion shield102is moved toward free end12of tendon10until it preferably comes into contact with free end12and/or crimp100. Preferably at least a portion of free end12, more preferably a portion of free end12and crimp100are inserted into trailing end126of insertion shield102.

Referring toFIG. 9, an opening is formed into a portion of bone20. The opening is preferably formed as a through-hole or bone tunnel30. The ends of suture104are inserted into and through bone tunnel30until they exit the opposite end of the tunnel. Suture104is moved to pull insertion shield102, crimp100and free end12of tendon10at least partially into bone tunnel30as shown inFIG. 10. Referring toFIG. 11, continued pulling on suture104moves the free end of tendon10out the other side of bone tunnel30, where the crimped portion of the free end may be severed if desired.

It will be appreciated that the steps described above may be performed in a different order, varied, or certain steps added or omitted entirely without departing from the scope of the present invention. For example only, instead of moving the crimped portion of free end12of tendon10completely through the bone tunnel, the crimped portion may be left in the bone tunnel.

FIGS. 12 to 18show additional preferred embodiments of the present invention. Unless otherwise noted, the description of crimp100above will be understood to apply to the embodiments inFIGS. 12 to 18as appropriate.

Referring now toFIGS. 12 and 13, a crimp200is shown in accordance with another preferred embodiment of the present invention. Crimp200is similar to crimp100except that wall210of crimp200forms a more complex cylindrical form with curved longitudinal surfaces218,220adjacent longitudinal slit222creating a double barrel crimp form for additional strength and hold on the tendon.FIG. 12shows crimp200in a non-compressed state.FIG. 13shows crimp200in a compressed state.

Referring now toFIG. 14, a crimp300is shown in accordance with another preferred embodiment of the present invention. Crimp300is similar to crimp100except that wall310of crimp300preferably includes a pair of orifices or apertures334therethrough. Apertures334are preferably oriented so that when crimp300is compressed, apertures334are opposite one another along an axis. As shown inFIG. 14, crimp300may be applied to free end12of tendon10before inserting the suture. Once crimp300is applied to free end12, a curved needle70attached to an end of the suture may be inserted through one of apertures334, through tendon10, and out the other of apertures334. Thereafter, free end12may be pulled through the bone tunnel in a manner similar to that described above with respect to crimp100.

Referring now toFIG. 15, a crimp400is shown in accordance with another preferred embodiment of the present invention. As shown inFIG. 15, crimp400may be formed as a compressible stent-like sleeve. Wall410of crimp400preferably has a circumferential lattice structure with a plurality of openings438. In use, the free end of the tendon is placed into passage416of crimp400. Thereafter, crimp400is crimped to reduce the minimum cross-section of the crimp and at least a portion of the free end of the tendon.

It will be appreciated that the minimum cross-section of crimp400may be reduced non-mechanically. For example only, crimp400may be made of a shape material such as nitinol that is programmed to contract or expand at a preset temperature. Crimp400may be formed from a non-metallic material or biomaterial, such as a biodegradable or bioresorbable material. The composition of such materials will be well-understood by those of ordinary skill in the art. When formed from a non-metallic or biomaterial, wall410may be configured to cinch around at least a portion of the free end of the tendon to trap the portion therein. A projection or thread may extend from one of the ends of the wall to facilitate pulling of the crimp through the opening in the bone.

Referring now toFIG. 16, an insertion shield102′ is shown in accordance with another preferred embodiment of the present invention. Insertion shield102′ is similar to insertion shield102except that it is spherically-shaped to facilitate insertion of crimp100and free end12of tendon10through the bone tunnel. The insertion shield may also be formed as other shapes, for example only, an ovoid or ellipsoid. The insertion shield may be formed as a separate component relative to the crimp, or may be formed as an integral part of the crimp, as described in further detail below. Suture104may be applied to tendon10prior to the application of the crimper, and then through insertion shield102′.

Referring now toFIGS. 17 and 18, a crimp500is shown in accordance with another preferred embodiment of the present invention. Crimp500is similar to crimp100except that insertion shield502is integrally formed with a main body portion542of crimp500. Body portion542has an interior surface512that preferably includes a plurality of surface roughenings544configured to enhance the securing of crimp500to the free end of the tendon. Insertion shield502and body portion542are connected to one another by a neck546. As shown inFIG. 17, insertion shield502is preferably formed in a frusto-conical bullet-nose configuration while body portion542is preferably initially planar or at least not entirely circular in a cross-section transverse to the longitudinal axis of the crimp. Crimp500may be applied by inserting the distal-most portion of the free end of the tendon into interior528of insertion shield502, then crimping body portion542around another portion of the free end of the tendon. Preferably, when body portion542is crimped, it will have an interior cross-section approximately equally to the maximum interior cross-section of insertion shield502.

Referring now toFIGS. 19 and 20, a crimp600is shown in accordance with another preferred embodiment of the present invention. Crimp600is similar to crimp100except that it includes a plurality of surface projections preferably formed as flexible spines, quills or fingers. In particular, wall610of crimp600has an interior surface612with a plurality of interior spines648, and an exterior surface614with a plurality of exterior spines650. As shown inFIG. 19, interior spines648each include a tip652that is preferably oriented toward first end606of crimp600. Interior spines648are preferably resilient and flexible so as to facilitate insertion of free end12of the end of tendon10into crimp600, while resisting expulsion of free end12therefrom.

Exterior spines650each include a tip654preferably oriented toward second end608of crimp600. Exterior spines650are preferably resilient and flexible so as to facilitate insertion of crimp600into the opening in the bone, while resisting expulsion of crimp600therefrom. The lengths of interior spines648and exterior spines650may be different compared to one another. For example, as shown inFIG. 19, the length of each interior spine648is preferably shorter than the length of each exterior spine650. The length of each interior spine648is preferably less than or equal to one-half the maximum inner dimension that is perpendicular to the length of crimp600. The length of each exterior spine650is preferably equal to or greater than one-half the maximum inner dimension that is perpendicular to the length of crimp600.

The foregoing description is by way of example only, and may be varied considerably without departing from the scope of the present invention. For example only, the crimp may be applied without a suture. In particular, the crimp may have a leading suture or wire already attached to it so that upon its application on the leading free end of the tendon graft, the assembly is ready for passage through the bone tunnel without having to apply a suture. Alternatively, the crimp may be pushed into the bone using, for example, a push-rod as described above.

The crimp may be configured for use without an insertion shield. For example only, the crimp may have a preconfigured, at least partially frusta-conical shape so that when crimped around the free end of the tendon, the crimp will have a taper adapted to facilitate insertion of the tendon into the bone tunnel.

The crimp may have a thickness that varies along its length. For example only, the exterior may have a preconfigured, at least partially frusto-conical shape while the interior of the crimp may be configured with a generally uniform passage, for example, a cylindrical passage.

Instead of, or in addition to the crimp having an at least partially frusto-conical shape, the crimping tool may be configured with a plate or plates that have an at least partially frusto-conical shape. For example only, a crimping tool with two at least partially frusto-conical plates may be configured to crimp the crimp so that the crimp is tapered from its trailing end towards its leading end. Such a configuration would reduce the need for an insertion shield.

The exterior surface of the crimp may include surface roughenings or projections650. The surface roughenings or projections650may be configured to facilitate insertion while resisting expulsion of the crimp from the opening in the bone, such as shown inFIGS. 19 and 20. The surface roughenings650may be configured, for example only, as a textured or etched surface or a pattern of dimples and/or grooves. Examples of surface projections650include ratchetings, or as shown inFIGS. 19 and 20spines, quills and/or fingers, which may be configured for one way insertion if desired. As shown inFIGS. 19 and 20exterior projections650extend in a generally arcuate configuration from the exterior wall of crimp600in a direction extending from end606toward end608. Moreover, as shown inFIG.19, exterior projections650are integral with, and made of the same material as, the crimp600.

The interior surface of the crimp may include surface roughenings or projections648to enhance the securing of the crimp to the tendon. The crimp may include surface roughenings or projections only on its interior surface, only on its exterior surface, or on both the interior and exterior surfaces. Where both the interior and exterior surfaces include surface roughenings or projections, such surface roughenings or projections may be differently configured. For example only, the interior surface may include surface roughenings, or a plurality of ratchets, while the exterior surface may include a plurality of one-way ratchets. As shown inFIGS. 19 and 20interior projections648extend from the interior wall of crimp600in a direction extending from end608toward the end606. Moreover, as shown inFIG. 19, interior projections648are integral with, and made of the same material as, the crimp600.

The wall of the crimp may include anywhere from zero to many openings as desired for the intended purpose. Such openings may be configured in a variety of ways, such as illustrated inFIGS. 14 and 15.

The slit formed by the longitudinal edges of the crimp may be linear, such as shown inFIG. 3, or non-linear. For example only, the edges of the slit may be curved (similar to a sine wave) or otherwise configured to interlock and inhibit translational movement of one edge relative to another edge. This has the advantage of better maintaining the form of the crimp during its insertion into the bone tunnel.

The crimp may be configured as a unitary body without a slit. An example is shown inFIG. 15with sleeve400. As another example, crimp600shown inFIGS. 19 and 20may be formed as a unitary body without a slit. The free end of the tendon may be compressed into the interior of the crimp with the push-rod. The flexible interior spines would then act to retain the free end of the tendon within the crimp. The crimp may then be left in the bone opening after withdrawing the push-rod. The crimp may be formed of a rubber material or a biomaterial as described above, and may have one or more openings through which the tendon may integrate with the bone.

The crimp and associated methods may be configured for only partial insertion into a bone structure. For example only, a surgeon may form an opening in a bone that is not a tunnel or through-hole, then insert the crimp into the opening such as shown inFIG. 20. If the crimp is formed from a biomaterial, the tendon will naturally integrate with the bone over time. By not forming a tunnel, more bone is preserved, speeding recovery of the patient.

If desired, the crimp and/or insertion shield may be combined with a material adapted to facilitate growth and integration between the tendon and bone. Examples of such materials would be apparent to those of ordinary skill in the art.

While various embodiments of the present invention have been described in relation to a crimp, it will be appreciated that the body of the device may be configured so that no crimping is necessary. Examples of such devices include a unitary body without a slit, such as described above, and/or devices formed from a shape memory material such as nitinol, which expands or contracts dependent upon a pre-set temperature.

The features described with respect to one embodiment may be applied to other embodiments, or combined with or interchanged with the features of other embodiments, as appropriate, without departing from the scope of the present invention.