Abstract:
A suture attachment device and method for securing a suture to an anatomic structure. The suture attachment device includes a cannulated member including a first surface and a second surface. A plurality of castellations extend axially outward from at least one of the first surface and the second surface, wherein each castellation includes a proximal end connected to the cannulated member, and a distal end located distal from the cannulated member, the distal end being flared radially outward relative to the proximal end.

Description:
FIELD 
       [0001]    The present disclosure relates to soft tissue attachment device. 
       BACKGROUND 
       [0002]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0003]    When soft tissue tears away or separates from bone, reattachment becomes necessary. Various devices, including sutures alone, screws, staples, wedges, and plugs have been used to secure soft tissue to bone. Anchors have been developed that are designed to be inserted into a pre-drilled hole. Other anchors are self-tapping. All of the above-noted anchors rely on a flight of threads disposed on the outer surface of a shank to secure it to the bone. They all provide a relatively easy method of fixation in hard, cortical bone. 
         [0004]    While the above-noted anchors work well for their intended purpose, improvements to the anchors may be beneficial in various areas. For example, improvements can be directed to an anchor&#39;s “pull-out” strength, and Improvements can be made to further reduce any tendency of the anchor to “back out” of the implantation site. Yet another improvement can be made to reduce any bone loss that may be incurred upon installation of the anchors. 
         [0005]    Accordingly, a need exists for an anchor that can be secured easily and effectively. A need also exists for an anchor that displaces a minimum amount of bone upon insertion. In addition, a need exists for an anchor having exceptional pull-out strength, and also averse to “backing out” of the ins ion site. 
       SUMMARY 
       [0006]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0007]    The present disclosure provides a suture attachment device for securing a suture to an anatomic structure. The suture attachment device includes a cannulated member including a first surface and a second surface; and a plurality of castellations extending axially outward from at least one of the first surface and the second surface, wherein each castellation includes a proximal end connected to the cannulated member, and a distal end located distal from the cannulated member, the distal end being flared radially outward relative to the proximal end. 
         [0008]    The present disclosure also provides a method of securing at least one suture to an anatomic structure. The method includes forming an aperture in the anatomic structure, and passing a suture through a cannulated member of a suture attachment device. The cannulated member includes a first surface and a second surface, and a plurality of prongs extending axially outward from at least one of the first surface and the second surface. Each prong includes a proximal end connected to the cannulated member, and a distal end located distal from the cannulated member. The distal end is flared radially outward relative to the proximal end. The method also includes knotting the suture to secure the suture to the suture attachment device, and passing the suture attachment device with the suture secured thereto through the aperture, wherein as the suture attachment device passes through the aperture, the prongs radially deflect inward, and after passing through the aperture, the prongs radially deflect outward and engage the anatomic structure to secure the suture to the anatomic structure. 
         [0009]    The present disclosure also provides a suture attachment device for securing a suture to bone, including a cannulated member including a first surface and a second surface; a plurality of deflectable first prongs extending axially and flaring radially outward from the first surface, the plurality of first prongs defining a sharpened end of the suture attachment device; and a plurality of second prongs extending axially outward from the second surface, the plurality of second prongs defining a blunt end of the suture attachment device. The plurality of first prongs and the plurality of second prongs define nesting features for engaging a plurality of the suture attachment devices together. 
         [0010]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0011]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0012]      FIG. 1  is a perspective view of a suture attachment device according to a principle of the present disclosure; 
           [0013]      FIG. 2  is a projected view of the suture attachment device of  FIG. 1 , in an unwrapped state; 
           [0014]      FIG. 3  is a top-perspective view of the suture attachment device of  FIG. 1 ; 
           [0015]      FIG. 4  is a bottom-perspective view of the suture attachment device of  FIG. 1 ; 
           [0016]      FIG. 5  is a side-perspective view of the suture attachment device of  FIG. 1 ; 
           [0017]      FIG. 6  is a perspective view of another suture attachment device according to a principle of the present disclosure; 
           [0018]      FIG. 7  is a projected view of the suture attachment device of  FIG. 6 , in an unwrapped state; 
           [0019]      FIG. 8  is a top-perspective view of the suture attachment device of  FIG. 6 ; 
           [0020]      FIG. 9  is a bottom-perspective view of the suture attachment device of  FIG. 6 ; 
           [0021]      FIG. 10  is a side-perspective view of the suture attachment device of  FIG. 6 ; 
           [0022]      FIG. 11  illustrates an exemplary suture attachment device according to a principle of the present disclosure securing a suture to a hard tissue anatomic structure such as bone; 
           [0023]      FIG. 12  illustrates an exemplary suture attachment device according to a principle of the present disclosure securing a suture to a soft tissue anatomic structure such as muscle; 
           [0024]      FIG. 13  illustrates a plurality of exemplary suture attachment devices according to a principle of the present disclosure securing a suture to an anatomic structure; 
           [0025]      FIG. 14  illustrates the plurality of exemplary suture attachment devices in  FIG. 13  nested together; 
           [0026]      FIG. 15  illustrates a plurality of exemplary suture attachment devices according to a principle of the present disclosure securing a plurality of sutures to an anatomic structure; and 
           [0027]      FIG. 16  illustrates another suture attachment device according to a principle of the present disclosure 
       
    
    
       [0028]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0029]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0030]      FIGS. 1-5  illustrate a suture attachment device  10  according to a first exemplary embodiment according to the present disclosure. Although the present disclosure references the attachment of a suture to an anatomic structure, it should be understood that the attachment device  10  may be used to attach a wire or some other anchoring means without departing from the scope of the present disclosure. Suture attachment device  10  includes a cylindrical annular ring  12 . Cylindrical ring  12  includes an exterior surface  14  and an interior surface  16  such that suture attachment device  10  is cannulated and allows suture  18  ( FIG. 11 ) to pass therethrough along axis A. Cylindrical ring  12  includes a first or upper surface  20  and a second or lower surface  22 . Suture attachment device  10  is crown-shaped such that a plurality of first castellations or first prongs  24  extend axially outward from first surface  20 . First prongs  24  also flare radially outward from axis A such that first prongs  24  are curved. First prongs  24  are also resilient so as to be deflectable. Although not required by the present disclosure, a plurality of second castellations or second prongs  26  may extend axially outward from second surface  22 . First prongs  24  are configured to engage an anatomic structure S such as bone, ligament, tendon, muscle, or some other tissue after the suture  18  has been passed through the anatomic structure S. In addition, each of first prongs  24  and second prongs  26  are designed to allow for nesting between multiple suture attachment devices  10 , as will be described in more detail below. 
         [0031]    First prongs  24  each include a proximal base end  28  connected to or unitary with first surface  20 , and a distal pointed end  30  distal from first surface  20 . Distal pointed ends  30  may be sharp to engage and fix suture attachment device  10  to anatomic structure S. Each prong  24  includes a first tapered surface  32  and a second tapered surface  34  that extend from proximal end  28  to distal end  30  and terminate at an apex  36  such that first prongs  24  have a length L 1 . As noted above, apex  36  can be sharp to engage and fix suture attachment device  10  to anatomic structure S. In the illustrated embodiment, first and second tapered surfaces  32  and  34  each include a radius of curvature such that first prongs  24  are fin-shaped. In addition, in the illustrated embodiment, first tapered surface  32  includes a greater radius of curvature in comparison to second tapered surface  34 . It should be appreciated, however, that first and second tapered surfaces  32  and  34  can include the same radius of curvature, or that second tapered surface  34  can include a greater radius of curvature in comparison to first tapered surface  32  without departing from the scope of the present disclosure. Furthermore, it should be appreciated that first prongs  24  flare radially outward from cylindrical ring  12  such that an outer diameter OD 2  of suture attachment device  10  defined by distal ends  30  is greater than the outer diameter OD 1  of cylindrical ring  12 . Although six first prongs  24  are illustrated in  FIG. 1  at sixty degree intervals around cylindrical ring  12 , it should be understood that any number of first prongs  24  is contemplated. For example, configurations including sets of two, three, four, and five first prongs  24  are contemplated. 
         [0032]    Second prongs  26  are similar to first prongs  24  in that each second prong  26  includes a proximal base end  38  connected to or unitary with second surface  22 , and a distal end  40  distal from second surface  20 . Each prong  26  includes a first tapered surface  42  and a second tapered surface  44  that extend from proximal end  38  to distal end  40  and terminate at a terminal end  46  such that second prongs  26  have a length L 2 . In the illustrated embodiment, L 1  is greater than L 2 . It should be understood, however, that L 1  can be equal to L 2 , or than L 2  may be greater than L 1  without departing from the scope of the present disclosure. First and second tapered surfaces  42  and  44  each include a radius of curvature such that second prongs  26  are fin-shaped. In addition, in the illustrated embodiment, first and second tapered surfaces  42  and  44  have an equal radius of curvature such that second prongs  26  are slightly curved. It should be appreciated, however, that first and second tapered surfaces  32  and  34  can include the different radii of curvature without departing from the scope of the present disclosure. Further, in contrast to first prongs  24 , second prongs  26  do not flare radially outward relative to cylindrical ring  12  and are not sharpened at distal ends  40 . Rather, second prongs  26  simply extend axially relative to cylindrical ring  12  and define a blunt end  41  of suture attachment device  10  to assist with insertion of second prongs  26  into anatomic structure S, as will be described in more detail below. Further, as noted above, the use of second prongs  26  allows for nesting between multiple suture attachment devices  10  at a single attachment site of anatomic structure S. In this regard, the spaces between adjacent first prongs  24  and adjacent second prongs  26  can be sized to allow for first prongs  24  or second prongs  26  of another suture attachment device  10  to engage therewith. Although six second prongs  26  are illustrated in  FIG. 1  at sixty degree intervals around cylindrical ring  12 , it should be understood that any number of second prongs  24  is contemplated. For example, configurations including zero, two, three, four, and five second prongs  26  are contemplated. 
         [0033]    To secure suture  18  to the anatomic structure S, suture  18  is first passed through cylindrical ring  12  in the direction from first prongs  24  to second prongs  26 . After passing through cylindrical ring  12 , suture  18  is tied to form a knot  48  to prevent suture  18  from passing back through cylindrical ring  12 . In this regard, an inner diameter ID of cylindrical ring  12  is slightly larger than the diameter of suture  18 . For example, if suture  18  has a diameter of 1 mm, inner diameter ID of cylindrical ring  12  can be approximately 1.25 mm to allow suture  18  to freely pass through cylindrical ring  12  before knotting and prevent suture  18  from passing back through cylindrical ring  12  after being knotted. 
         [0034]    After suture  18  is secured to relative to suture attachment device  10 , suture attachment device  10  including suture  18  is inserted into a pre-drilled aperture or bore  50  formed in the anatomic structure S. In the illustrated embodiment, a ligament L is being attached to an anatomic structure S that is a bone B including a cortical bone layer  100  and a cancellous bone layer  102 , with pre-drilled aperture  50  being formed in cortical bone layer  100 . The pre-drilled aperture  50  has a diameter substantially equal to an outer diameter OD of cylindrical ring  12 . Specifically, second prongs  26  are aligned with aperture  50  and suture attachment device  10  is pressed through aperture  50  using an insertion device (not shown). As suture attachment device  10  is being pressed through aperture  50 , first prongs  24  will begin to deflect radially inward. That is, as noted above, first prongs  24  are flared radially outward relative to cylindrical ring  12 , and first prongs  24  are also deflectable. Thus, as suture attachment device  10  is being inserted through aperture  50 , first prongs  24  can deflect radially inward to allow suture attachment device  10  to pass entirely through aperture  50 . After passing entirely through aperture  50 , first prongs  24  will deflect radially outward to their original flared position within cancellous bone layer  102 . Because cancellous bone layer  102  is porous and “spongy” relative to cortical bone layer  100 , first prongs  24  are able to deflect outward and engage with either cortical bone layer  100  or pores within cancellous bone layer  102  to lock suture attachment device  10  within the bone B. That is, because first prongs  24  will return to their original flared position, apexes  36  are free to engage the bone B as suture  18  is tightened such that suture attachment device  10  acts like an anchor. In this manner, suture  18  is securely fastened to anatomic structure S to secure ligament L to bone B. 
         [0035]    It should be understood that when suture attachment device  10  is being used to secure suture  18  to a soft tissue such as muscle, the formation of aperture  50  is not necessary. More specifically, referring to  FIG. 12 , it can be seen that anatomic structure S is a muscle M, and that suture attachment device  10  including suture  18  has merely been pressed into muscle M such that no pre-drilled aperture  50  is necessary. In this instance, first prongs  24  may still deflect radially inward to allow suture attachment device  10  to pass entirely into muscle M. After entering the soft tissue such as muscle M, first prongs  24  will deflect radially outward to their original flared position within the soft tissue such as muscle M. 
         [0036]    As illustrated in  FIG. 13 , it should be understood that suture  18  can be passed through a plurality of suture attachment devices  10  before being knotted. After passing suture  18  and each suture attachment device  10  through aperture  50 , and while suture  18  is being tightened relative to anatomic structure S, the suture attachment devices  10  may begin to bunch up ( FIG. 13 ). As the suture attachment devices  10  begin to bunch up, first and second prongs  24  and  26  begin to act as nesting features that allow attachment devices  10  to nest with each other. That is, first and second prongs  24  and  26  may mate with first and second prongs  24  and  26  of adjacent suture attachment devices  10  to form a larger “anchor” that secures suture  18  to anatomic structure S. In this manner, a more robust attachment of suture  18  to anatomic structure S can be made. 
         [0037]    Although each suture attachment device  10  illustrated in  FIG. 13  is the same size, it should be understood that differently sized suture attachment devices  10  could be used. For example, a larger suture attachment device  10  could be located proximate anatomic structure S, and progressively smaller suture attachment devices  10  could be used as the distance from anatomic structure S increases. Alternatively, a suture attachment device  10  could be used proximate anatomic structure S and progressively larger suture attachment devices  10  could be used as the distance from anatomic structure S increases. 
         [0038]    It should also be understood that, as illustrated in  FIG. 15 , a plurality of sutures  18  each having a suture attachment device  10  can be passed through aperture  50 . After passing each suture  18  including a respective suture attachment device  10  through aperture  50 , and while each suture  18  is being tightened relative to anatomic structure S, the suture attachment devices  10  may begin to bunch up (see, e.g.,  FIG. 14 ). As the suture attachment devices  10  begin to bunch up, first and second prongs  24  and  26  begin to act as nesting features that allow attachment devices  10  to nest with each other. That is, first and second prongs  24  and  26  may mate with first and second prongs  24  and  26  of adjacent suture attachment devices  10  to form a larger “anchor” that secures suture  18  to anatomic structure S. In this manner, a more robust attachment of sutures  18  to anatomic structure S can be made. 
         [0039]    Now referring to  FIGS. 6 to 10 , a second exemplary embodiment will be described. Suture attachment device  10   a  includes a cylindrical annular ring  12   a . Cylindrical ring  12   a  includes an exterior surface  14   a  and an interior surface  16   a  such that suture attachment device  10   a  is cannulated and allows suture  18  ( FIG. 11 ) to pass therethrough along axis B. Cylindrical ring  12   a  includes a first or upper surface  20   a  and a second or lower surface  22   a . A plurality of first castellations or first prongs  24   a  extend axially outward from first surface  20   a  such that suture attachment device  10   a  is crown-shaped. First prongs  24   a  also flare radially outward from axis B such that first prongs  24   a  are curved. First prongs  24   a  are also resilient so as to be deflectable. Although not required by the present disclosure, a plurality of second castellations or second prongs  26   a  may extend axially outward from second surface  22   a . First prongs  24   a  are configured to engage an anatomic structure S such as bone or ligament after the suture  18  has been passed through the anatomic structure. 
         [0040]    First prongs  24   a  each include a proximal base end  28   a  connected to or unitary with first surface  20   a , and a distal end  30   a  distal from first surface  20   a . Each prong  24   a  includes a first tapered surface  32   a  and a second tapered surface  34   a  that extend from proximal end  28   a  to distal end  30   a  and terminate at an apex  36   a  such that first prongs  24   a  have a length L 1 . Apex  36   a  can be sharp to engage and fix suture attachment device  10  to anatomic structure S. In the illustrated embodiment, first and second tapered surfaces  32   a  and  34   a  are linear such that first prongs  24   a  are triangle-shaped. 
         [0041]    First prongs  24   a  flare radially outward from cylindrical ring  12   a  such that an outer diameter OD 2  of suture attachment device  10   a  defined by distal ends  30   a  is greater than the outer diameter OD 1  of cylindrical ring  12   a . Although six first prongs  24   a  are illustrated in  FIG. 6  at sixty degree intervals around cylindrical ring  12   a , it should be understood that any number of first prongs  24   a  is contemplated. For example, configurations including sets of two, three, four, and five first prongs  24   a  are contemplated. 
         [0042]    Second prongs  26   a  are similar to first prongs  24   a  in that each second prong  26   a  includes a proximal end  38   a  connected to or unitary with second surface  22   a , and a distal end  40   a  distal from second surface  20   a . Each prong  26   a  includes a first tapered surface  42   a  and a second tapered surface  44   a  that extend from proximal end  38   a  to distal end  40   a  and terminate at a terminal end  46   a  such that second prongs  26   a  have a length L 2 . In the illustrated embodiment, L 1  is greater than L 2 . It should be understood, however, that L 1  can be equal to L 2 , or than L 2  may be greater than L 1  without departing from the scope of the present disclosure. In the illustrated embodiment, first and second tapered surfaces  42   a  and  44   a  are linear such that second prongs  26   a  are essentially triangle-shaped. It should be noted, however, that terminal end  46   a  is rounded rather than defining a sharp point, which assists in inserting suture attachment device  10   a  through aperture  50 . Further, in contrast to first prongs  24   a , second prongs  26   a  do not flare radially outward relative to cylindrical ring  12   a . Rather, second prongs  26   a  simply extend axially relative to cylindrical ring  12   a  and define a blunt end  41   a  of suture attachment device  10  to assist with insertion of second prongs  26   a  into anatomic structure S, as was discussed in detail above. Further, as noted above, the use of second prongs  26   a  allows for nesting between multiple suture attachment devices  10   a  at a single attachment site of anatomic structure S. In this regard, the spaces between adjacent first prongs  24   a  and adjacent second prongs  26   a  can be sized to allow for first prongs  24   a  or second prongs  26   a  of another suture attachment device  10   a  to engage therewith. Although six second prongs  26   a  are illustrated in  FIG. 6  at sixty degree intervals around cylindrical ring  12   a , it should be understood that any number of second prongs  26   a  is contemplated. For example, configurations including zero, two, three, four, and five second prongs  26   a  are contemplated. 
         [0043]    Now referring to  FIG. 16 , a suture attachment device  10   b  is illustrated. Suture attachment device  10   b  includes a cylindrical annular ring  12   b . Cylindrical ring  12   b  includes an exterior surface  14   b  and an interior surface (not shown) such that suture attachment device  10   b  is cannulated and allows suture  18  ( FIG. 11 ) to pass therethrough along axis C. Suture attachment device  10   b  includes a plurality of first castellations or first prongs  24   b  such that suture attachment device  10   b  is crown-shaped. First prongs  24   b  also flare radially outward from axis C such that first prongs  24   b  are curved. First prongs  24   b  are also resilient so as to be deflectable. 
         [0044]    Suture attachment device  10   b  also includes a plurality of second castellations or second prongs  26   b . Second prongs  26   b  are similar to first prongs  24   b  in that each second prong  26   b  also flares radially outward from axis C such that second prongs  26   b  are curved. Second prongs  24   b  are also resilient so as to be deflectable. 
         [0045]    Suture attachment device  10   b  also includes a plurality of third castellations or third prongs  52 . Third prongs  52  are similar to first and second prongs  24   b  and  26   b  in that each third prong  52  also flares radially outward from axis C such that third prongs  52  are curved. Third prongs  52  are also resilient so as to be deflectable. The use of first  24   b , second  26   b , and third prongs  52  increase the pull-out strength of suture attachment device  10   b . Although annular ring  12   b  has been described as cylindrical, annular ring  12   b  may be cone-shaped or tapered without departing from the scope of the present disclosure. 
         [0046]    In each of the exemplary embodiments, suture attachment devices  10  and  10   a  may be formed from materials such as stainless steel, titanium or titanium alloy, nitanol, resorbable magnesium, polyether ether ketone (PEEK), or polyethylene. To form suture attachment devices  10  and  10   a , a cylindrical tube may be laser processed to form the first and second prongs. Alternatively, suture attachment devices  10  and  10  may be micro-molded, or formed using 3D printing techniques. 
         [0047]    The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.