Patent Publication Number: US-2007123984-A1

Title: Ligament attachment and repair device

Description:
BACKGROUND  
      The present invention relates to devices for attaching an end of a ligament to a bone or for repairing a tear in a ligament.  
      Injury or damage to a ligament may cause an end of the ligament to detach from the bone. In these cases, it is desirable to re-attach the end of the ligament to the bone. In other cases, injury or damage to the ligament may cause a centralized tear in the ligament at a position between the two ends, leaving the two ends attached to the bone. If the ligament is salvageable, it is desirable to reunite the two loose ends of the torn ligament. In either of these cases, if the ligament is not salvageable, the ligament may be removed and an artificial or harvested graft ligament may be implanted. Many current ligament attachment systems require, first, drilling a tunnel into the bone. The ligament is attached to the bone by using a fastener to draw the ligament into and secure the ligament in the bone tunnel. Although effective, this system may be complex and the procedure may be significantly invasive.  
      There is a need for a relatively simple and minimally invasive implantable attachment device for attaching an end of a ligament to a bone or for repairing a tear in a ligament.  
     SUMMARY  
      The present invention provides an implantable attachment device for attaching an end of a ligament to a bone. In one form, the attachment device includes a patch. The patch includes a bone engaging face and a ligament engaging face. The patch is positionable between the bone and the end of the ligament and is adapted to be fastened to a surface of the bone such that the bone engaging face bears against the surface of the bone. The ligament engaging face is adapted to receive a ligament fastener for attaching the end of the ligament to the patch. The device may also include a reinforcing patch positionable atop and attachable to the patch, such that the end of the ligament is positioned between the ligament engaging faces of the patch and the reinforcing patch.  
      The present invention also provides an implantable device for re-attaching two ends of a torn ligament to one another. In one form, the device includes a patch having an exterior face and an interior face. The patch is adapted to receive at least one ligament fastener for attaching the two ends of the ligament to the interior surface of the patch. The patch is formable to wrap around the two ends of the ligament.  
      In another form, the device includes a first patch and a second patch. Each of the first and second patches may be formed of a woven material and includes an interior ligament face and an exterior face. The woven material is adapted to receive a ligament fastener for attaching the ends of the ligament to the interior ligament face. The first patch is positionable adjacent a first side of the ends of the ligament. The second patch is positionable atop the first patch and adjacent an opposite second side of the ends of the ligament such that the ends of the ligament are positioned between the interior faces of the first and second patches. The second patch is attachable to the first patch.  
      In still another form, the invention contemplates a ligament repair system for replacing a damaged ligament. The ligament replacement system includes a replacement ligament having a first bone engaging end and a second bone engaging end. First and second patches are respectively coupled to the first and second bone engaging ends, and each of the first and second patches has a bone engaging face and a ligament engaging face. Each of the first and second patches is adapted to be fastened to a surface of a respective bone such that the bone engaging face bears against the surface of the respective bone. The system also includes a ligament fastener. The ligament engaging face is adapted to receive the ligament fastener to attach the first and second bone engaging ends of the ligament to the first and second patches, respectively. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:  
       FIG. 1  is a medial aspect of a knee with a ligament attached at one end to the tibia using an attachment device of the present invention;  
       FIG. 2A  is a front view of the attachment device of  FIG. 1 ;  
       FIG. 2B  is a side view of the attachment device of  FIG. 1 ;  
       FIG. 3  is a medial aspect of a knee with the respective ends of a ligament attached to the tibia and femur using an attachment device of the present invention;  
       FIG. 4A  is a medial aspect of a knee with a ligament attached to the tibia at one end using an attachment device of the present invention;  
       FIG. 4B  is an anterior aspect of the knee and the attachment device of  FIG. 4A ;  
       FIGS. 5A-5D  illustrate a medial aspect of a knee with a ligament having a centralized tear and the repair of that tear using an attachment device of the present invention;  
       FIG. 6A  is an interior surface view of an attachment device of the present invention;  
       FIG. 6B  is an interior surface view of the attachment device of  FIG. 6A  in a partially folded configuration;  
       FIG. 6C  is a perspective view of the attachment device of  FIG. 6A  in a substantially folded configuration; and  
       FIG. 6D  is a medial aspect of a knee wherein the attachment device of  FIG. 6A  is used to repair a ligament. 
    
    
      Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. Although the exemplification set out herein illustrates embodiments of the invention, in several forms, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed.  
     DETAILED DESCRIPTION  
      The embodiments hereinafter disclosed are not intended to be exhaustive or limit the invention to the precise forms disclosed in the following description. Rather the embodiments are chosen and described so that others skilled in the art may utilize its teachings.  
      Referring first to  FIG. 1 , a knee joint is illustrated including femur F, tibia T and tibial collateral ligament L. Ligament L, due to damage or injury to the knee, has detached from tibia T at ligament end L E . Attachment device  10  is used to re-attach ligament end L E  to tibia T. Referring now to  FIGS. 1, 2A  and  2 B, device  10  includes patch  12  having bone engaging face  14  and ligament engaging face  16 . As is described in further detail below, bone engaging face  14  is adapted to bear against a bone, such as tibia T, while ligament engaging face  16  is adapted to receive ligament fastener  26  for fastening ligament end L E  to patch  12 .  
      Patch  12  may be formed of any material that would permit attachment of ligament fastener  26  thereto. For instance, patch  12  may be formed of a woven material. The woven material may be woven of any surgical grade fibers including metal fibers, plastic fibers, synthetic fibers such as Kevlar®, rayon, acetate, and polyester or mixtures thereof. Alternatively, the material of patch  12  may be in the form of a porous fabric or a molded lattice. The composition and structure of the material of patch  12  is such that it provides patch  12  with a strength and rigidity that resists deformation and tearing when attached ligament L pulls on patch  12  during knee movement. At the same time, the composition and weave of patch  12  may maintain some flexibility to allow patch  12  to form to the surface of tibia  12 . Patch may have a variety of shapes and thicknesses. For instance, patch  12  may be substantially flat, thin and square. Alternatively, patch  12  may be elongated to provide more ligament contact area. As discussed below, patch  12  may be contoured on one or both sides to facilitate attachment to tibia T and attachment of ligament end L E  thereto.  
      Patch  12  is adapted to be fastened to tibia T using bone fasteners  20 . For example, if patch  12  is formed of a woven material, the material may be woven loosely enough to allow a driving end of bone fasteners  20  to be driven through patch  12 , yet woven tightly enough to prevent the head of fasteners  20  from passing through the material thereby securing patch  12  to tibia T. Alternatively, as illustrated in  FIGS. 1 and 2 A, patch  12  may include bone fastener openings  18  extending therethrough from ligament engaging face  16  to bone engaging face  14 . Bone fastener openings  18  receive bone fasteners  20  to secure patch  12  to tibia T. Bone fasteners  20  may be any fasteners capable of attaching to bone including screws, pins, nails, anchors, and staples. Patch  12  may be reinforced about the perimeter of openings  18  to provide additional support, durability and resistance to tearing around fasteners  20 . For instance, the woven material forming patch  12  may be more tightly woven around openings  18  to create stronger reinforced area  22  surrounding openings  18 . Alternatively, patch  12  may include grommets around openings  18 .  
      As mentioned above, ligament engaging face  16  is adapted to receive ligament fastener  26  for attaching ligament end L E  to patch  12 . Referring to  FIG. 1 , the material of patch  12  is accessible at ligament engaging face  16  and, as noted above, is structured to allow the fixation of ligament fastener  26  thereto. For instance, ligament fasteners  26  may be sutures formed of surgical thread or fibers that may be securely stitched to the material of patch  12 . Alternatively, ligament fasteners may be in the form of staples or clips that can be securely fastened to the material of patch  12 . To further facilitate the attachment of ligament L E  to patch  12 , ligament engaging face  16  may be contoured to receive ligament end L E  and to allow ligament end L E  to rest in and against ligament engaging face  16 . For instance, ligament engaging face  16  may have a recess defined therein sized and configured to receive ligament end L E .  
      Also noted above, bone engaging face  14  is adapted to bear against tibia T. More particularly, bone engaging face  14  may be contoured to complement the surface of tibia T. Alternatively, patch  12  may be flexible such that bone engaging face  14  conforms to the surface of tibia T. In another alternative, bone engaging face  14  may be structured to provide a pliable layer that is capable of conforming to the surface of tibia T. Additionally or alternatively, the material of patch  12  may be structured to provide bone engaging face  14  with a mesh that facilitates the ingrowth of bone into patch  12 , thereby further securing patch  12  to tibia T.  
      Further, as illustrated in  FIG. 2B , bone engaging face  14  may include bone engaging layer or coating  24  having a composition designed to facilitate the engagement of bone engaging face  14  to tibia T. For example, bone engaging layer  24  may provide a porous scaffolding for the ingrowth of tibia T. Such porous scaffolding may be formed of hydrogels. Suitable hydrogels may include polyvinyl pyrollidone, polyvinyl alcohol, polyurethane, polyacrylamide, calcium alginate, hyaluronic acid, polyethylene glycol and polyhydroxyethylmethacrylate. In addition or in the alternative, bone engaging layer  24  may include biologic material such as pharmaceuticals and therapeutics. For example, bone engaging layer  24  may include pharmaceuticals such as antibiotics, anticoagulants, anti-inflammatories, steroids and other compositions that prevent infection, facilitate healing and/or encourage bone ingrowth. Bone engaging layer may also include therapeutics such as growth factors, periosteal cells, ligament cells, blood, antibodies or other materials. Such pharmaceuticals and therapeutics may be loaded into a hydrogel scaffold or may be suspended in a composition, such as hydrogel, and formed into layer  24 .  
      Turning now to  FIG. 3 , device  10  may be used to attach both ends of a ligament to any bone. Furthermore, device  10  is not restricted to re-attaching natural ligaments to bone. Device  10  may be used in ligament replacement procedures to attach the respective ends of artificial or replacement ligament L A  to femur F and tibia T. Ligament L A  may be a synthetic or harvested graft ligament. In fact device  10  may be a ligament replacement system that includes artificial ligament L A . In this case, ligament L A  may be of similar structure and composition as patch  12 . For instance, ligament L A  may be formed of a flexible surgical grade woven material. The woven material may be woven of any surgical grade fibers including metal fibers, plastic fibers, synthetic fibers such as Kevlar®, rayon, acetate, and polyester or mixtures thereof. Alternatively, ligament L A  may be formed of a woven material different from that of patch  12 , such that ligament L A  has a resiliency mimicking that of the natural ligament while patch  12  has strength and rigidity to resist deformation and tearing when attached ligament L A  pulls on patch  12  during knee movement.  
      Ligament L A  may have a smooth outer layer or coating to prevent or minimize irritation of surrounding tissues. The outer layer may be comprised of hydrogel woven with the fibers of the woven material forming ligament L A . In this ligament replacement system, each end of ligament L A  would be coupled to a patch, such as patch  12  described above, for use in attached the ends to respective femur F and tibia T. The ends of ligament L A  may be attached to patch  12  using any means including sutures, staples or other attachment device. Alternatively, ends of L A  may be formed integrally with patch  12 . For instance, the woven material of ligament L A  may be woven together at its ends with the woven material of patch  12 .  
      Turning now to  FIGS. 4A and 4B , another embodiment of the present invention is shown. Attachment device  110  includes patch  112  and reinforcing patch  28 . Patch  112  is substantially the same as patch  12  of device  10  ( FIGS. 1-2A ). Accordingly, patch  112  may be similarly secured to tibia T, and ligament end L E  may be secured to patch  112 . Reinforcing patch  28  is configured to fit atop patch  112  and over ligament L thereby sandwiching ligament end L E  between patch  112  and reinforcing patch  28 . Similar to patch  12 , both patch  112  and reinforcing patch  28  are formed of a material that permits the attachment of ligament fastener  26  thereto. The material of patch  112  and reinforcing patch  28  may be a weave of metal fibers, plastic fibers, and/or synthetic fibers such as Kevlar®, acetate, rayon and polyester. Alternatively, the material of patch  112  and reinforcing patch  28  may be in the form of a molded lattice or porous fabric.  
      Patch  112  and reinforcing patch  28  are adapted to receive bone fasteners  20 , which extend through both reinforcing patch  28  and patch  112  to attach device  110  to bone. For example, patch  112  and reinforcing patch  28  may include bone fastener openings (not shown) through which bone fasteners  20  may extend. Bone fastener openings of reinforcing patch  28  may be aligned with bone fastener openings of patch  112  to facilitate fixation of device  110  to tibia T with bone fasteners  20 . Bone fastener openings of both patch  112  and reinforcing patch  28  may be reinforced as described above with respect to patch  12  to form reinforced area  122  around bone fastener openings. Alternatively, fasteners  20  may be used to secure patch  112  to bone, while reinforcing patch  28  may be fixed to patch  112  using fasteners (not shown), such as sutures, staples or clips. The fasteners may extend through ligament end L E  to secure both ligament end L E  and reinforcing patch  28  to patch  112 . Reinforcing patch  28  reinforces the fixation of ligament end L E  to tibia T by compressing and holding ligament end L E  between patch  112  and reinforcing patch  28 .  
      Reinforcing patch  28  includes an interior ligament engaging face (not shown) and an exterior face  30 . Interior ligament face may exhibit a mesh structure, which may help grip and hold ligament end L E  to further secure the fixation of ligament end L E  to tibia T. Exterior face  30  of reinforcing patch  28  may include a smooth coating (not shown) to prevent or minimize irritation of surrounding tissues. The smooth coating of exterior face  30  may be formed of hydrogel or ceramics.  
      Turning to  FIGS. 5A-5D , the present invention also contemplates an embodiment that may be used to repair a centralized tear in a ligament; that is, a tear in the ligament at a position between the two ends such that the ends remain attached to bone. As illustrated in FIG. SA, ligament L has suffered a centralized tear leaving loose ligament ends L 1  and L 2 . Attachment device  210  generally includes first patch  34  and second patch  36 . Each of first and second patches  34 ,  36  are formed of material similar to those described above with respect to patch  12 . In other words, first and second patches may be formed of woven metal fibers, plastic fibers and/or synthetic fibers. Alternatively, first and second patches may be formed of material such as a molded lattice or porous fabric. Each of first and second patches include interior face  35  and exterior face  37 .  
      As shown in  FIG. 5B , first patch  34  is positioned on one side of ligament L between femur F and ligament L. Ligament ends L 1 , L 2  are pulled together and attached to first patch  34  using ligament fasteners  26 , such as sutures, staples, or clips (FIG. SC). Second patch  36  is placed over ligament ends L 1 , L 2  and atop first patch  34  thereby positioning ligament ends L 1 , L 2  between interior faces  35  of first and second patches  34 ,  36 .  
      Interior face  35  of each of first and second patches  34 ,  36  may include a ligament growth layer or coating (not shown). The ligament growth layer may include materials designed to induce the fusion of ligament ends L 1 , L 2 . For example, ligament growth layer may include growth factors, ligament cells, antibiotics, steroids, and other biologics that may encourage fusion of ligament ends L 1 , L 2 . The ligament growth layer may also include a ligament growth scaffold to provide a matrix for the growth and fusion of ligament ends L 1 , L 2 .  
      Exterior face  37  of each of first and second patches  34 ,  36  may include a smooth coating or layer to minimize interference by surrounding tissues during the movement of the ligament. Exterior face (not shown) of first patch  34 , particularly, may have a smooth coating upon which femur F can glide. As patch  34  moves with the stretching, contracting, and other movement of ligament L, femur F may glide along the smooth coating such that the interaction between femur F and first patch  34  does not interfere with the movements of ligament L. Exterior face  37  of second patch  36  may also have a smooth surface upon which surrounding soft tissues can glide, thereby preventing or minimizing irritation of surrounding tissues. For example, the smooth surface may be formed of hydrogels or ceramics.  
      Referring now to  FIGS. 6A-6D , attachment device  310  is shown. Device  310  includes patch  42  formed of a flexible material  43 . Patch  42  includes interior ligament face  44  and opposite exterior face  46 . Patch  42  is deformable to fold or roll over to wrap around two loose ends of tom ligament L ( FIG. 6D ). Accordingly, material  43  may be a woven material or fabric formed of metal fibers, plastic fibers, or other synthetic fibers including Kevlar® rayon, acetate, and polyester. The material of patch  42  is structured to provide deformability and to receive ligament fasteners  50 , but stiff enough to maintain folded shape and support torn ligament ends of ligament L. Interior ligament face  44  of patch  42  may include ligament growth layer  48 . Ligament growth layer  48  may comprise a scaffold for the growth and development of ligament L and to facilitate the fusion of the two ligament ends. Ligament growth layer  48  may also include biologics such as growth factors, ligament cells, or other materials that may induce the fusion of the two ends of ligament L.  
      Exterior face  46  of patch  42  may include a smooth coating or layer  49  upon which surrounding bone and soft tissue can glide, thereby minimizing the interference by surrounding tissues of the movement of ligament L.  
      As illustrated in  FIG. 6D , patch  42  may be wrapped around the loose ends of ligament L, such that interior ligament face  44  surrounds the loose ends of ligament L. Ligament fasteners (not shown) may be used to attach the loose ends of ligament L to patch  42 . Patch  42  may then be rolled or folded around ligament L. Fasteners  50  may be used to attach loose ends to folded/rolled patch  42  and hold patch  42  in its folded or rolled configuration. Fasteners  50  may include, for example, sutures, staples, or other fasteners. Ligament growth layer  48  facilitates the fusion of loose ends of ligament L to one another by providing biologics and scaffolding for the growth and development of ligament L. Patch  42  may be formed of biodegradable materials such that patch  42  degrades when fusion of loose ends of ligament L is achieved.  
      It should be understood that the attachment device of the present invention may have various sizes and shapes. Furthermore, the attachment device is not limited to use with ligaments of the knee, but rather is useful for the attachment or repair of various soft tissues, such as ligaments and tendons, in various locations of the body, such as ankle, hip, wrist, and others.  
      While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.