Abstract:
In one aspect, the present disclosure relates to a tap guide including a shaft having a proximal portion and a distal portion, a handle coupled to the proximal portion of the shaft, and a tip coupled to the distal portion of the shaft. A method and system for preparing a bone tunnel for receipt of a fixation device is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to United States Patent Application No. 61/033,106 filed on Mar. 3, 2008, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field of Technology 
         [0003]    The present disclosure relates to the preparation of a bone tunnel for receipt of a fixation device during ligament reconstruction surgery, and more specifically, a tap guide for use in such preparation. 
         [0004]    2. Related Art 
         [0005]    A ligament, such as an anterior cruciate ligament (ACL), that has ruptured and is non-repairable, is generally replaced arthroscopically by a soft tissue graft. The soft tissue graft can be harvested from a portion of a patellar tendon having so called “bone blocks” at each end, and from the semitendonosis and gracilis. Alternatively, the soft tissue graft can be formed from synthetic materials or from a combination of synthetic and natural materials. 
         [0006]    The replacement soft tissue graft is implanted by securing one end of the soft tissue graft in a bone tunnel within the femur, and passing the other end of the graft through a tunnel formed in the tibia. The graft may be secured in the tunnels via the use of a fixation member, such as a screw, that is positioned between the wall of the tunnel and the tissue graft. While the fixation screw is being advanced through the tunnel, it is important that there be enough of a pathway to substantially reduce the possibility of screw breakage and graft rotation, yet allow enough contact for adequate screw fixation. Therefore, adequate preparation of the bone tunnel is required to achieve this goal. 
       SUMMARY 
       [0007]    In one aspect, the present disclosure relates to a tap guide including a shaft having a proximal portion and a distal portion, a handle coupled to the proximal portion of the shaft, and a tip coupled to the distal portion of the shaft. In an embodiment, the tip includes a groove having a tapered depth along a length of the groove. The groove is between about 40% to about 65% deeper at a second end of the groove relative to a first end of the groove. In another embodiment, the tip is located at an angle α; between about 2° to about 4°, relative to a longitudinal axis of the shaft. In yet another embodiment, the tip includes a diameter of between about 4 mm and about 12 mm. In a further embodiment, the shaft includes a through hole and a groove extending a length of the shaft. In yet a further embodiment, the proximal portion of the shaft includes a circular shape. In an embodiment, the handle includes a proximal portion and a distal portion wherein the distal portion is located at an angle relative to the proximal portion and the proximal portion is positioned substantially perpendicular to the proximal portion of the shaft. 
         [0008]    In another aspect, the present disclosure relates to a method of preparing a bone tunnel for receipt of an anchor. The method includes providing a tap guide including a shaft having a proximal portion and a distal portion, a handle coupled to the proximal portion of the shaft, and a tip coupled to the distal portion of the shaft; providing a tap; inserting the tip into the bone tunnel; inserting the tap into a through hole of the shaft and into the bone tunnel to create a notch in a wall of the bone tunnel; and removing the tip from the bone tunnel. In an embodiment, the method further includes inserting an end of a tissue graft into the bone tunnel and inserting a fixation device into the bone tunnel via the notch, wherein the fixation device is located between the tissue graft and a wall of the notch. In another embodiment, the tip includes a groove having a tapered depth along a length of the groove such that during creation of the notch the tap cuts deeper in a first area of the notch than in a second area of the notch. In yet another embodiment, the diameter of the tip is substantially equal to the diameter of the bone tunnel. In a further embodiment, the notch is configured such that rotation of the tissue graft does not occur during insertion of the anchor into the bone tunnel. 
         [0009]    In yet another aspect, the present disclosure relates to a system for preparing a bone tunnel for receipt of a fixation device. The system includes a tap; and a tap guide including a shaft having a proximal portion and a distal portion, a handle coupled to the proximal portion of the shaft, and a tip coupled to the distal portion of the shaft. In an embodiment, the tip includes a groove having a tapered depth along a length of the groove. In another embodiment, the groove is between about 40% to about 65% deeper at a second end of the groove relative to a first end of the groove. In yet another embodiment, the tip is located at an angle α, between about 2° to about 4°, relative to a longitudinal axis of the shaft. In a further embodiment, the tip includes a diameter of between about 4 mm and about 12 mm. In yet a farther embodiment, the shaft includes a through hole and a groove extending a length of the shaft. In an embodiment, the proximal portion of the shaft includes a circular shape. 
         [0010]    Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the disclosure, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present disclosure and together with the written description serve to explain the principles, characteristics, and features of the disclosure. In the drawings: 
           [0012]      FIG. 1  shows a perspective view the tap guide of the present disclosure. 
           [0013]      FIG. 2A  shows a perspective view of the shaft of the tap guide of the present disclosure. 
           [0014]      FIG. 2B  shows a perspective view of the shaft and tip of the tap guide of the present disclosure. 
           [0015]      FIG. 3A  shows a perspective view of the tip of the present disclosure. 
           [0016]      FIG. 3B  shows a front view of the tip of the present disclosure. 
           [0017]      FIG. 4  shows a perspective view of a tap of the present disclosure. 
           [0018]      FIG. 5  shows a perspective view of the tap guide and tap during creation of a notch in a bone tunnel. 
           [0019]      FIG. 6A  shows a cross-sectional view of a bone tunnel and notch of the present disclosure. 
           [0020]      FIG. 6B  shows a perspective view of the bone tunnel and notch of  FIG. 6A . 
           [0021]      FIG. 7A  shows a front view of a second area of a notch of a first embodiment of the present disclosure. 
           [0022]      FIG. 7B  shows a front view of a first area of the notch of  FIG. 7A . 
           [0023]      FIG. 8A  shows a front view of a second area of a notch of a second embodiment of the present disclosure. 
           [0024]      FIG. 8B  shows a front view of a first area of a notch of a second embodiment of the present disclosure. 
           [0025]      FIG. 9  shows a soft tissue graft and fixation device within the bone tunnel and notch of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0026]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. 
         [0027]      FIG. 1  shows the tap guide  10  of the present disclosure. The tap guide  10  includes a shaft  11  having a proximal portion  11   a  and a distal portion  11   b,  a handle  12  coupled to the proximal portion  11   a  of the shaft  11 , and a tip  13  coupled to the distal portion  11   b  of the shaft  11 . The handle  12  includes a proximal portion  12   a  positioned substantially perpendicular to a longitudinal axis  11   d  of the shaft  11  and a distal portion  12   b  located at an angle to the proximal portion  12   a.  The distal portion  12   b  is configured for providing a user with a proper grip during surgery, as will be further described below. It is within the scope of this disclosure that the proximal portion  12   a  may be positioned parallel, or at an angle to, the longitudinal axis  11   d  of the shaft  11 . It is also within the scope of this disclosure that the distal portion  12   b  may be in-line with or not at an angle to the proximal portion  12   a.    
         [0028]    As shown in  FIGS. 2A and 2B , the shaft  11  includes a through hole  11   c  extending a length of the shaft  11 . The through hole  11   c  is configured for insertion of a tap, as will be more fully described below. Additionally, the shaft  11 , including the proximal portion  11   a,  is substantially circular in shape. However, the distal portion  11   b  of the shaft  11  is beveled to facilitate coupling of the tip  13  to the distal portion  11   b  . The distal portion  11   b  may be beveled via machining or any other type of process. The tip  13  is located at an angle α, between about 2° and about 4°, relative to a longitudinal axis  11   d  of the shaft  11 . However, for the purposes of this disclosure, the angle α may range from between about 0° to about 45°. Also for the purposes of this disclosure, the shaft  11  may be a shape other than circular. 
         [0029]    As shown in  FIGS. 3A and 3B , the tip  13  includes a first end  13   a,  a second end  13   b,  and a groove  14  having a tapered depth along a length of the groove  14  such that the groove  14  is between about 40% to about 65% deeper at a second end  14   a ″ of the groove  14  relative to a first end  14   a ′ of the groove  14 . The tip  13  also includes a laser mark  15  that will be used as a guide in controlling the insertion depth of the tip  13  and the tap into the bone tunnel, as will be further described below. The laser mark  15  is located between about 25 mm to about 35 mm from the first end  13   a  of the tip  13 . 
         [0030]      FIG. 4  shows a tap  20  that is used in cooperation with the tap guide  10  to create a notch in a bone tunnel during surgery, such as ligament reconstruction surgery, as will be further described below. The tap  20  includes a shaft  21  and a handle  22  coupled to a proximal portion  21   a  of the shaft  21 . Additionally, the shaft  21  includes a distal portion  21   b  having threads  21   b ′ and configured for creating the notch in the bone tunnel, as will be further described below. The distal portion  21   b  also includes a laser mark  21   b ″ for cooperating with the laser mark  15  on the tip  13  in controlling the insertion depth of the tap  20  into the bone tunnel, as will be further described below. The handle  22  includes protrusions  22   a  that are configured for providing a user with a proper grip during creation of the notch. 
         [0031]    As mentioned above, during ligament reconstruction surgery, the damaged ligament is removed and bone tunnels are created in the tibia and in the femur. A soft tissue graft, such as a patellar tendon or other soft tissue graft, is placed within the tunnels with one end of the graft being placed in the tibial tunnel and the other end of the graft being placed in the femoral tunnel. The ends may be fixated in the tunnels by a fixation device, such as a bone screw or other fixation device, by inserting the fixation device between walls of the tunnels and the soft tissue grafts. However, for appropriate insertion of the fixation device, the insertion sight must be properly prepared. Otherwise, cracking of the screws and/or twisting of the soft tissue graft may occur. 
         [0032]      FIG. 5  shows the use of the tap guide  10  and the tap  20  for creating a notch in a wall of the bone tunnel  31  of a bone  30  during ligament reconstruction surgery, such as ligament reconstruction surgery. Such a notch creates enough of a pathway to substantially reduce the possibility of graft rotation and/or screw breakage, but allow enough contact between the screw and the graft for screw fixation. After creation of the bone tunnel  31  via a drill or other device for creating bone tunnels, the tip  13  of the tap guide  10  is inserted into the bone tunnel  31  until the laser mark  15  is aligned with the opening  31   a  to the tunnel  31 . The tip  13  has a diameter that is substantially equal to the diameter of the bone tunnel  31 . The diameter of the tip  13  is between about 4 mm and about 12 mm. After insertion of the tip  13 , the tap  20  is then inserted into the through hole  11   c  of the shaft  11  and subsequently inserted into the bone tunnel  31  by rotating the tap  20  such that the threaded distal portion  21   b  of the shaft  21  creates a notch in the wall  32  of the bone tunnel  31 . The tap  20  is rotated until the laser mark  21   b ″ of the tap  20  is aligned with the laser mark  15  of the tip  13 . The threaded distal portion  21   b  extends about 2.5 cm along the length of the shaft  21 . Consequently, the length of the notch is also about 2.5 cm. This length helps to substantially reduce screw breakage upon insertion of the screw into the bone tunnel  31  and allows rotation of the screw to occur the entire length, as will be more fully described below. 
         [0033]      FIGS. 6A and 6B  show the notch  40  that is created in the wall  32  of the bone tunnel  31 . As stated above, the tip  13  includes a groove  14  having a tapered depth along a length of the groove  14 . Consequently, during the creation of the notch  40 , the distal portion  21   b  of the tap  20  cuts deeper in a first area  40   a  of the notch  40  than in a second area  40   b  of the notch  40 . This difference in depth is more clearly shown in  FIGS. 7A-7B  and  8 A- 8 B. The bone tunnels  31  in  FIGS. 7A-B  and  8 A-B are 6 mm and 10 mm, respectively. A tap having a 4 mm diameter shaft was used to make the notch  40 .  FIGS. 7A and 8A  show the notch  40  in the second area  40   b  of the notch  40  and  FIGS. 7B and 8B  show the notch  40  in the first area  40   a  of the wall  40 . 
         [0034]    After creation of the notch  40 , the tip  13  of the tap guide  10  and the tap  20  are removed from the bone tunnel  31 . As shown in  FIG. 9 , a tissue graft  50  is then inserted into the bone tunnel  31  and a fixation device  60 , such as a bone screw, is inserted into bone tunnel  31 , via the notch  40 , and located between the tissue graft  50  and a wall  40   c  of the notch  40 . The screw  60  is inserted via an insertion device. The screw  60  may be inserted into the bone tunnel  31  until an end of the screw  60  is flush with the opening  31   a  of the bone tunnel  31 , however the depth of the screw  60  into the tunnel  31  will vary depending on surgical technique, as is shown in  FIG. 9  where the screw  60  is located more towards the second area  40   b  of the notch  40 . Having a notch  40  with a deeper first area  40   a  allows for easier insertion of the fixation device  60  into the tunnel  31  while still allowing enough contact between the device  60  and the soft tissue graft  50 . 
         [0035]    The shaft  11 , handle  12 , and tip  13  of the tap guide  10  are each made via a machining process, such as grinding, milling, reaming, ram, or wire EDM and include a biocompatible metal material, such as stainless steel or titanium alloy. However, other processes or materials may be used. The handle  12  and tip  13  are coupled to the shaft  11  via a soldering or welding process such as silver soldering, tig welding, laser welding, or any other type of soldering or welding process. In addition, a process other than soldering or welding may be used to couple the handle  12  and tip  13  to the shaft  11 . The groove  14  in the tip  13  is made via a machining process, such as grinding, milling, reaming, ram, or wire EDM. However, other processes may be used. 
         [0036]    The shaft  21  and handle  22  of the tap  20  are each made via a machining or sheet metal stamping process, such as grinding, milling, reaming, ram, or wire EDM and include a biocompatible metal material, such as stainless steel or titanium alloy. However, other processes or materials may be used. The threads  21   b ′ on the distal portion  21   b  of the shaft  21  are created via a machining process, such as grinding, milling, reaming, ram, or wire EDM. However, other processes may be used. The handle  22  of the tap  20  is coupled to the shaft  21  via a soldering or welding process such as silver soldering, tig welding, laser welding, or any other type of soldering or welding process. In addition, a process other than soldering or welding may be used to couple the handle  22  to the shaft  21 . 
         [0037]    As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the disclosure, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.