Abstract:
A suture anchor comprises an anchor body having a proximal end, a distal end, a longitudinal axis and bone engaging external threads oriented for rotation about the longitudinal axis. A longitudinal axial bore extends into the body from its proximal end and at least one lateral passage passes from the axial bore outwardly through the body. A suture attachment element disposed within the axial bore has at least one protruding member having a first position disposed within the axial bore and a second position protruding outwardly from the anchor body through the at least one lateral passage. The protruding member inhibits rotation of the suture anchor body within the bone.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the priority benefit of U.S. Provisional Application No. 61/388,031, filed Sep. 30, 2010, the entire contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    This invention relates to suture anchors for attaching suture to bone, and more specifically to such suture anchors which employ a suture management feature. 
         [0003]    It is known to use suture anchors for attaching soft tissues such as ligaments or tendons to adjacent bone. Threaded suture anchors employ external threads and are rotated into the bone, usually into a pre-drilled bone hole, to affix the suture anchor to the bone. Backing out of a threaded anchor is undesirable. 
       SUMMARY OF THE INVENTION 
       [0004]    A suture anchor according to the present invention comprises an anchor body with a proximal end, a distal end, a longitudinal axis and bone engaging external threads oriented for rotation about the longitudinal axis. A longitudinal axial bore extends into the body from its proximal end. At least one lateral passage passes from the axial bore outwardly through the body. A suture attachment element is disposed within the axial bore and has at least one protruding member. The protruding member has a first position disposed within the axial bore and a second position protruding outwardly from the anchor body through the at least one lateral passage. When the protruding member is in the second position with the anchor threaded into a bone the protruding member prevents the anchor from unthreading itself out of the bone. 
         [0005]    The suture anchor can comprise a length of suture attached to the suture attachment element. Preferably, the suture attachment element is oriented such that proximal force applied thereto urges the suture attachment element from the first position into the second position. In one aspect of the invention, the body comprises a plurality of lateral passages and the suture attachment element comprises a plurality of protruding members, each of which align with a corresponding lateral passage. The suture attachment element can comprise a length of spring metal having a first proximally extending end forming a first protruding member, a second proximally extending end forming a second protruding member and an intermediate loop adapted to receive a length of suture. 
         [0006]    Preferably, the suture anchor is provided sterile and packaged in a bacteria proof enclosure. 
         [0007]    A method according to the present invention, provides for attaching tissue to a bone. The method comprises the step of: passing a first portion of a suture length through the tissue; embedding into the bone a suture anchor, the suture anchor comprising an anchor body comprising an anchor body having a proximal end, a distal end, a longitudinal axis and bone engaging external threads oriented for rotation about the longitudinal axis, a longitudinal axial bore extending into the body from its proximal end, at least one lateral passage passing from the axial bore outwardly through the body; and a suture attachment element disposed within the axial bore having at least one protruding member having a first position disposed within the axial bore and a second position protruding outwardly from the anchor body through the at least one lateral passage, the step of embedding being performed while the suture attachment is in the first position; and moving the suture attachment into the second position such that the at least one protruding member extends beyond the suture anchor body into the bone to resist rotation of the suture anchor body within the bone. 
         [0008]    Preferably, the step of moving the suture attachment into the second position comprises applying a proximal force to the suture attachment via a suture attached to the suture attachment. The suture can be attached to a piece of soft tissue, such as for example a rotator cuff tendon, to attach the tissue to the bone. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an exploded perspective view of a suture anchor according to the present invention; 
           [0010]      FIG. 2  is a perspective view of a suture receiver of the suture anchor of  FIG. 1 ; 
           [0011]      FIG. 3  is a perspective view of the suture receiver of  FIG. 2  with an alternative method for engaging multiple suture loops; 
           [0012]      FIG. 4 . is a cut-away view of the suture anchor of  FIG. 1  being implanted into a bone; 
           [0013]      FIG. 5  is an exploded perspective view of a further embodiment of a suture anchor according to the present invention; 
           [0014]      FIG. 6  is an exploded perspective view of a further embodiment of a suture anchor according to the present invention; 
           [0015]      FIG. 7A  is a perspective view of a further embodiment of a suture anchor according to the present invention; 
           [0016]      FIG. 7B  is an exploded perspective view of the distal portion of the suture anchor of  FIG. 7A ; and 
           [0017]      FIG. 7C  is a cut-away view of the distal portion of the suture anchor of  FIG. 7A . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 1  illustrates a suture anchor  10  according to the present invention. Suture anchor  10  comprises a distal body portion  12  which connects to a proximal body portion  14  both of which are held together by a pin  16  through respective cross-bores  18  and  20  in the distal body portion  12  and the proximal body portion  14 . The distal body portion  12  is generally cylindrical in shape having a proximal end  22  through which the cross-bore  18  passes and a distal end  24  which tapers inwardly for easier insertion of the suture anchor  10  into a bone hole (not shown in  FIG. 1 ). An external screw thread  26  encircles the distal body portion  12 . 
         [0019]    The proximal body portion  14  is also generally cylindrical in shape and bears an external screw thread  28  which mates with the thread  26  to form a continuous threading about the suture anchor  10 . An axial-bore  30  passes through the proximal body portion  14 . A distal portion  32  thereof, has a larger diameter than a proximal portion  34  thereby creating an internal annual abutment  36 . The proximal portion  34  has a hexagonal cross-section to accommodate a driving tool (not shown in  FIG. 1 ). One with ordinary skill in the art would appreciate that alternative tool/anchor engagements may be employed. 
         [0020]    The bore-distal portion  32  has a circular cross section and is sized to closely accommodate the body distal portion proximal end  22 . A suture receiver  38  fits within the axial-bore distal portion  32  between the abutment  36  and the distal body portion proximal end  22 . It has a circular cross-section and is sized to rotate freely about a longitudinal axis  40  of the suture anchor  10 . Six axial suture bores  42 A-F pass through the suture receiver  38 . 
         [0021]    Turning also now to  FIG. 2 , the suture bores  42 A-F accommodates three suture loops  44 A-C. Alternatively, as shown in  FIG. 3 , a suture strand  46  can be woven through the suture bores  42 A-F such that the suture loops  44 A-C can be threaded through portions of the suture strand  46  extending above the suture receiver  38 . Ends  48  of the each of the suture loops  44 A-C extend proximally out of the suture anchor  10  through the axial bore  30 . The suture ends  48  can then be attached to soft tissue as is understood by one of skill in the art for attaching that soft tissue to a bone. For instance, in a rotator cuff repair, each of the suture loops  44 A-C may extend through the rotator cuff tendon at different locations to effect a repair. 
         [0022]    The design of the suture anchor  10  provides advantages both in manufacturability and in performance. Having the suture loops  44 A-C attach internal of the suture anchor and extending out through the axial bore  30 , provides a preferred angle of exit toward soft tissue versus a proximal attachment point. With the separate distal body portion  12  and proximal body portion  14  attaching the suture loops  44 A-C deep within the suture anchor  10  becomes easier during manufacturing. When inserting a conventional threaded anchor, any suture loops extending therefrom tend to twist due to the twisting of the anchor in its insertion. The present suture receiver  38  is free to rotate within the axial bore  30  thus reducing twisting of the suture loops  44 A-C as the suture anchor  10  is inserted. 
         [0023]    Turning also now to  FIG. 4 , preferably, the suture anchor  10  is inserted into a bone  50  having a pre-drilled hole  52 . A driver  54  having an elongated body  56  and an external hex shape at its distal tip  58 , mates with the hex shaped axial bore proximal portion  34 . The suture loops  44 A-C extend proximally out of the suture anchor  10  through a canulation  60  through the driver distal tip  58  and body  56 . In one preferred embodiment, the canulation  60  is open  62  along one side much that after the suture anchor is driven into the bone hole  52  by the driver  54 , the driver  54  can be removed from the suture anchor  10  with the suture loops  44 A-C disengaging from the driver  54  through the canulation opening  62 . 
         [0024]      FIG. 5  illustrates and alternative embodiment of a suture anchor  70  comprising a distal threaded body portion  72  and proximal threaded body portion  74 . The suture anchor  70  is similar in most respects to the suture anchor  10 . However, the proximal body portion  74  carries an additional thread start  76  at its proximal portion  78  thereby effectively increasing thread pitch at the proximal portion  78  and thus enhancing purchase within the hard cortical bone (not shown in  FIG. 5 ) with which this portion typically engages. Also, the anchor  70  employs a somewhat different suture receiver  80 . 
         [0025]    The suture receiver  80  comprises a central cylindrical body  82  having a proximally extending suture eyelet  84 . A distally extending post  86  terminates in an annular flange  88 . The anchor distal body portion  72  has an axial bore  90  having a distal body portion  92  sized to accommodate the flange  88  and a narrower proximal portion  94  sized to accommodate the post  86  with the diameter differences creating an internal annular abutment  96  against which the flange  88  bears preventing its proximal movement out of the bore  90 . A lateral cut out  98  is provided in the distal body portion  72  to allow the flange  88  and post  86  to be inserted laterally into distal bore  90 . This arrangement allows the suture receiver  80  to rotate freely within the distal bore ( 90 ). 
         [0026]    Several bosses  98  extend outwardly radially from the suture receiver body  82  and fit closely, yet with rotation, within an axial bore  100  in the proximal body portion  74 . Suture loops (not shown in  FIG. 5 ) can be passed through the eyelet  84  and also, if desired, around each of the bosses  98 , and then proximally out of the anchor through the bore  100 , the loops about the bosses being held by the bosses  98  and not being able to slip between the bosses  98  and the body  74  due to the close fit of the bosses  98  within the bore  100 . 
         [0027]      FIG. 6  illustrates a further embodiment of a suture anchor  110  similar to that shown in  FIG. 5 . A suture receiver  112  is rotatably received within a distal body portion  114  as in the previous embodiment however its proximal end  116  is structured differently. It is cylindrical and bears three suture eyelets  118  A-C which are spaced apart both axially and rotationally, with the middle eyelet  118  B passing laterally through the proximal end  116  at 45 degrees with respect to the top eyelet  118  A and bottom eyelet  118  C and with the top and bottom eyelets  118  A and  118  C passing laterally through the proximal end and being oriented normal to each other. The placement and orientation of the eyelets  118  A-C assists in suture management, both in separation and in identification of individual loops. 
         [0028]      FIGS. 7  A-C. illustrate a further suture anchor  120  having an alternative suture receiver  122  in the form of a bent loop  124  of spring metal having proximally extending ends  126 . It is received within an axial bore  128  of a distal body portion  130  of the anchor  120  (which attaches to a proximal body portion  131 ). One or more lengths of suture (not shown in  FIGS. 7  A-C) can attach to the loop  124 . Proximal force therefrom draws the ends  126  up along a camming ledge  132  within the bore  128  toward angled side ports  134  from the bore  128  through the distal body portion  130 , allowing the ends  126  to protrude from the distal body portion  130  (see  FIG. 7  C) and provide additional fixation within a bone (not shown in  FIGS. 7  A-C). While the anchor  120  is being inserted a distal end  136  of a cannulated insertion tool  138  keep the ends  126  within the bore  128  and distal of the ports  134  while allowing rotation of the suture receiver  122  within the bore  128 . 
         [0029]    The invention now being fully described, it will be apparent to one of ordinary skill in the art that many modifications and changes can be made thereto without departing from the spirit or scope of the invention as defined in the following claims.