Abstract:
An implant useful for reconstructing a knee that has sustained a rupture or tear of an anterior cruciate ligament. The implant has first and second opposed member connected by a replacement graft. The members may have external screw threads. In addition there is a method of reconstructing a knee using the implant of the present invention, wherein the knee has sustained an anterior cruciate ligament injury.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to implants for arthroscopic surgical procedures, in particular to implants and associated procedures for replacing an anterior cruciate ligament in the knee. 
       BACKGROUND OF THE INVENTION 
       [0002]    Arthroscopic surgical repairs of a ruptured anterior cruciate ligament in the knee are known in this art. A rupture of the anterior cruciate ligament (“ACL”) is often seen in sports related injuries. In a conventional arthroscopic ACL reconstruction procedure, the surgeon prepares the patient for surgery by insufflating the patient&#39;s knee with sterile saline solution. Several cannulas are inserted into the knee and used as entry portals into the interior of the knee. A conventional arthroscope is inserted through one of the cannulas so that the surgeon may view the surgical site remotely. The surgeon then drills a tibial tunnel and a femoral tunnel in accordance with conventional surgical techniques using conventional surgical drills and drill guides. A replacement anterior cruciate ligament graft is then prepared and mounted in the tibial and femoral tunnels, and secured using conventional techniques and known fixation devices in order to complete the knee reconstruction. 
         [0003]    Several types of anterior cruciate ligament grafts are available for use by the surgeon in ACL reconstruction. The grafts may be autografts that are harvested from the patient, for example, patellar bone-tendon-bone grafts, or hamstring grafts. Alternatively, the grafts can be xenografts, allografts, or may be prepared using natural or synthetic polymers. There are various known methods of securing these ACL grafts in bone tunnels. These methods include the use of fixation devices such as one or more cross-pin intersecting the tunnel to retain the graft, interference screws driven between the graft and a wall of the bone tunnel, or any of various other retention devices applied during surgery for positioning, tensioning and securing the graft. 
         [0004]    Although the existing methods for performing ACL reconstruction are satisfactory for their intended purpose, and generally provide the patient with the desired therapeutic result, these surgical procedures are considered by some to be complex and generally leave one or more implants, such as cross pins or interference screws, in the patient. In certain cases it is believed that implants may trigger immune responses in the patient, or otherwise interfere with healing, for example, by reducing the area of direct contact between the ACL graft tendon and the patient&#39;s native tissue. It would thus be desirable to reduce or eliminated the use of fixation devices in ACL surgery, and particularly the use of fixation devices remaining in the patient after surgery. 
         [0005]    Accordingly, there is a need in this art for improved devices and methods of ACL reconstruction having reduced complexity and reduced dependence on fixation devices that behave post-surgically as foreign bodies in the patient. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention relates to arthroscopic procedures and implants, and particularly to implants and procedures for replacing an anterior cruciate ligament in the knee. It is an object of the present invention to provide a surgical implant that includes one or more integrated fixation device for deployment in a bone tunnel during arthroscopic surgery such as ACL repair surgery, thereby reducing or eliminating the requirement for additional fixation devices to position and retain the implant. 
         [0007]    It is a further object of the present invention to provide an integrated implant for arthroscopic surgery that can be implanted and tensioned using a single installation tool. 
         [0008]    It is yet a further object of the present invention to provide improved ACL replacement surgical procedures having reduced procedural complexity and a reduction in the number foreign bodies remaining in the body after surgery. 
         [0009]    Accordingly, an implant is disclosed for replacing an anterior cruciate ligament in a knee. The implant includes a first fixation member having an axis and a first substantially cylindrical external surface about the axis. The first surface defines first external screw threads adapted for threaded engagement with first internal screw threads formed in a tunnel in a tibia adjacent to the knee. The first external screw threads have a first major thread diameter and a first minor thread diameter. The implant also includes a second fixation member having a second substantially cylindrical external surface about the axis. The second surface defines second external screw threads adapted for threaded engagement with second internal screw threads formed in a tunnel in a femur adjacent to the knee. The second external screw threads have a second major thread diameter and a second minor thread diameter. The implant also includes a flexible graft ligament member interconnecting the first fixation member and the second fixation member. 
         [0010]    In one embodiment, the first fixation member, the second fixation member and the ligament member are made using allograft tissue. In another embodiment, the first fixation member, the second fixation member and the ligament member are made using xenograft tissue. In a further embodiment, at least one of the first and the second fixation member is reinforced with a biocompatible material. In another embodiment, the first and the second fixation member and the ligament member are manufactured using synthetic biocompatible material. 
         [0011]    In different embodiments, the second major thread diameter is equal to the first thread diameter, or the second major thread diameter is smaller than the first minor thread diameter. In an embodiment where the second major thread diameter is smaller than the first minor thread diameter, the second fixation member can be passed through the tunnel in the tibia without engaging the internal screw threads therein 
         [0012]    The implant may also include an axial bore through the first fixation member and at least partially through the second fixation member. In different embodiments, the axial bore has a polygonal or an oval internal cross section. The axial bore is adapted for sliding engagement with an insertion tool for the implant, the tool including a proximal handle and a distal shaft fixed to the handle and adapted for sliding engagement with the axial bore. When the implant is mounted on the tool, the handle is positioned outside the axial bore. Either or both of the first and the second fixation member may also include one or more transverse bore in fluid communication with the axial bore and with the respective external surface. The one or more transverse bore can be used to deliver a fluid to a surgical site. For delivering the fluid to the surgical site, the tool may include a cannulation through the handle and at least partially through the shaft. 
         [0013]    Another aspect of the present invention is a kit including the tool and the implant, where the implant includes the axial bore. The kit may include an implant with the second major thread diameter equal to the first major thread diameter, or may include the implant with the second major thread diameter smaller than the first minor thread diameter. The implant in the kit may also include the one or more transverse bore and the cannulated tool. 
         [0014]    Yet another aspect of the present invention is an implant that includes tissue harvested from a mammal. The tissue includes a ligament member having a first end and a second end. A first bone block is attached substantially at the first end and a second bone block is attached substantially at the second end. External screw threads are present on at least one of the first and the second bone block. These external threads are adapted for threaded engagement with internal screw threads formed in a tunnel in a bone of a living patient. 
         [0015]    Still another aspect of the present invention is an implant that includes a graft ligament having a first end and a second end. A first bone block is attached to the graft ligament substantially at the first end. The first bone block is adapted to fit within a tunnel in a bone, the tunnel having a wall. A second bone block is attached to the graft ligament substantially at the second end. The first bone block includes an edge adapted to wedge against the wall of the tunnel in response to tension applied to the graft ligament by pulling on the second bone block. 
         [0016]    Yet another aspect of the present invention is a method for replacing an anterior cruciate ligament in a knee. The method includes steps of forming an internally screw threaded first tunnel through a tibia adjacent to the knee, and forming an internally screw threaded second tunnel in a femur adjacent to the knee. The method also includes providing a threaded implant as described herein, the implant having an axial bore for receiving an insertion tool, and providing the insertion tool including a handle fixed to an elongated shaft adapted for sliding engagement with the axial bore through the first fixation member and at least partially through the second fixation member. 
         [0017]    The method further includes slidingly engaging the tool with the first and the second fixation member, passing the second fixation member through the internally threaded first tunnel, and simultaneously rotationally threading the first fixation member into the internally threaded first tunnel and the second fixation member into the internally threaded second tunnel. In one embodiment, the second fixation member is passed through the internally threaded first tunnel by engaging the second external threads in the internally threaded first tunnel and rotationally threading the second fixation member through the internally threaded first tunnel. In another embodiment, the second major thread diameter is smaller than the first minor thread diameter, and the second fixation member is passed axially through the first tunnel without screw thread engagement. 
         [0018]    The method may also include steps of disengaging the tool from the second fixation member while leaving the tool engaged with the first fixation member, tensioning the implant by rotating the tool and the first fixation member engaged therewith, then disengaging the tool from the first fixation member. In another embodiment, the method includes injecting a fluid through the implant, wherein the implant defines at least one transverse bore in fluid communication with the axial bore and at least one of the first and the second external surface, the tool further including a cannulation in fluid communication with the at least at least one transverse bore. In various embodiments, the fluid is an adhesive, a medicant, or a lubricant. 
         [0019]    Still another aspect of the present is a method for repairing a knee of a patient. The method includes the steps of preparing a tibial tunnel in a tibia adjacent to the knee and preparing a femoral tunnel in a femur adjacent to the knee. The method also includes the step of providing an implant including a graft ligament having a first end and a second end, a first bone block attached to the first end and a second bone block attached to the second end, each of the first and the second bone block including an integral fixation device for fixation in a bone tunnel. The method also includes steps of fixating the first bone block in the femoral tunnel using the first fixation device; and fixating the second bone block in the tibial tunnel using the second fixation device. 
         [0020]    These and other aspects of the present invention will be more apparent from the following description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  illustrates an embodiment of an implant of the present invention including a ligament graft with an integral externally threaded fixation members at proximal and distal ends, the fixation members being of substantially equal diameter; the implant is shown in a knee. 
           [0022]      FIG. 2  illustrates a proximal end view of an embodiment of the implant of  FIG. 1 , the implant including a polygonal cross section longitudinal bore for receiving an insertion tool. 
           [0023]      FIG. 3  illustrates an end view of another embodiment of the implant of  FIG. 1 , the implant including an oval cross section longitudinal bore for receiving an insertion tool. 
           [0024]      FIG. 4  illustrates an embodiment of an implant of the present invention including a ligament graft with fully circumferentially threaded fixation members at proximal and distal ends. 
           [0025]      FIG. 5  illustrates an embodiment of an implant of the present invention including a ligament graft with externally threaded fixation members at proximal and distal end ends, the fixation members being of unequal diameter. 
           [0026]      FIG. 6  illustrates an embodiment of an implant of the present invention including a ligament graft having externally threaded fixation members at proximal and distal ends, at least one of the fixation members including fluid injection ports. 
           [0027]      FIG. 7  illustrates an embodiment of an implant of the present invention including a ligament graft having a toggle-type fixation member connected at one end. 
           [0028]      FIG. 8  illustrates an embodiment of a polygonal external cross section insertion tool for a threaded implant of the present invention having a mating, polygonal internal cross section longitudinal bore. 
           [0029]      FIG. 9  illustrates an embodiment of a cannulated insertion tool for an implant of the present invention, for delivering a fluid to a surgical site. 
           [0030]      FIG. 10  illustrates an embodiment of an oval external cross section insertion tool for an implant of the present invention having a mating oval internal cross section longitudinal bore. 
           [0031]      FIG. 11  illustrates an embodiment of an insertion tool for a toggle-type implant of the present invention. 
           [0032]      FIGS. 12 through 15  illustrate an embodiment of a procedure for mounting a threaded implant of the present invention in a joint. 
           [0033]      FIGS. 16 and 17  illustrate an embodiment of a procedure for mounting a toggle-type implant of the present invention in a joint. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0034]    Referring more particularly to the figures,  FIG. 1  illustrates an embodiment of a threaded implant  100  according to the present invention. The implant  100  has a distal end  102 , a proximal end  104 , and a longitudinal axis  106  extending therebetween. The implant  100  also includes a distal fixation member  108  for fixing the implant into a first internally threaded tunnel in bone  110 , a proximal fixation member  112  for fixing the implant into a second internally threaded tunnel in bone  114  and an interconnecting flexible ligament member  116  extending between the distal fixation member  108  and the proximal fixation member  112 . The implant  100  can be fashioned from harvested allograft or xenograft tissue suitable for a bone-tendon-bone implant, or manufactured from natural or synthetic materials including biocompatible polymers, ceramics, minerals, and combinations thereof. The flexible ligament member  116  may be integral with one or both of the distal  108  and the proximal fixation member  112 , or the distal fixation member  108 , the proximal fixation member  112  and the flexible ligament member  116  may be separately harvested or manufactured components that are assembled to form the implant  100 . In an embodiment, the implant  100  is a BTB allograft, and each of the distal  108  and the proximal fixation member  112  is formed from a harvested bone block at an end of the allograft. 
         [0035]    The distal fixation member  108  is substantially cylindrical in shape and includes external screw threads  118  centered about the longitudinal axis  106  and having a major thread diameter  120 , a minor thread diameter  122 , and a longitudinal thread spacing  124 . By major thread diameter of an external screw thread, we mean the outer diameter of an external screw thread measured at peaks of the threads. A major thread diameter of a threaded fixation member corresponds to an outer diameter of the fixation member. By minor thread diameter of an external screw thread, we mean the diameter of an external screw thread measured from the bottom of valleys between the threads. Longitudinal thread spacing (thread spacing) is the longitudinal distance between adjacent threads, and is inversely related to thread pitch, that is, thread pitch equals 1/thread spacing. Thread depth is the radial distance between the peaks and valleys of the thread, equal to half of the difference between the major thread diameter and the minor thread diameter. 
         [0036]    The proximal fixation member  112  is substantially cylindrical in shape has external screw threads  126  of substantially the same screw thread specifications with regard to major diameter  120 , minor diameter  122  and thread spacing  124  as the distal fixation member  108 . Screw threads may be formed on the implant  100  by any thread forming method suitable for fabricating a surgical implant. Examples of suitable external thread-forming methods for the distal  108  and proximal fixation member  112  may include mechanical thread cutting, laser or water-jet cutting, and pressure forming. Preparation of the implant may also include reinforcing one or both bone blocks with a biocompatible material such as a bone cement, an apatite composition, or a curable polymeric material. The reinforcing material may be a bioreplaceable material or a nonabsorbable material or a combination thereof. 
         [0037]    Fixation members of the present invention are sized similarly to bone blocks used in conventional ACL repair surgery, typically in the range of 15 millimeters to forty millimeters in length, and eight millimeters to twenty millimeters in diameter. In one embodiment of the present invention, a major thread diameter of a fixation member is in the range of eight to twenty millimeters. In another embodiment, the major thread diameter is in the range of twelve to fifteen millimeters. In an embodiment, the thread pitch is in the range of six to twelve threads per inch and the thread depth is in the range of 0.04 inches to 0.125 inches. 
         [0038]    The implant  100  also includes an axial bore  128  through the proximal fixation member  112  and at least partially through the distal fixation member  108 . In the embodiment illustrated in  FIG. 1 , the axial bore  128  in the distal fixation member  108  is closed at the distal end  102 . In another embodiment, the distal fixation member  108  is bored through to the distal end  102 . The axial bore  128  is adapted for internal sliding, removable engagement with a tool for rotating the implant  100  about the axis  106 , for threading the implant  100  through the second internally threaded tunnel  114  and into the first internally threaded tunnel  110 . In an embodiment, the implant  100  is an ACL graft implant, the second internally threaded tunnel  114  is a bore in a tibia and the first internally threaded tunnel  110  is in a femur. In an embodiment, fixation of the implant  100  in a threaded bone tunnel requires as fixation means only the external threads  118 ,  126  fashioned from the material of respective bone blocks or their synthetic equivalents. That is, the fixation means for the implant  100  is unitary with the implant  100 . 
         [0039]      FIG. 2  illustrates a proximal end view  130  of an embodiment of the implant  100  of  FIG. 1 , wherein the axial bore  128  has a hexagonal cross section  132 . The cross section of the bore  128  may also be another cross section, such as another polygonal cross section, adapted for sliding, removable engagement with an insertion tool having a corresponding external cross section.  FIG. 3  illustrates a proximal end view  134  of another embodiment of the implant  100  of  FIG. 1 , wherein the bore  128  has an oval cross section  136  for sliding, removable engagement with an insertion tool having a corresponding oval external cross section. By an oval cross section, we mean any elongated cross section having rounded ends, for example, an ellipse or a flat-sided elongated shape with rounded ends. 
         [0040]    The external screw threads  118 ,  126  of the implant  100  are interrupted at a circumferential position  138  about the axis  106 , corresponding to the orientation of the flexible ligament member  116  of the implant. The interruption of the threads  118 ,  126  is included to avoid damage to the ligament member  116  of the implant  100  when the threads  118 ,  126  are formed or when the implant  100  is threaded into the first  110  or the second internally threaded tunnel.  FIG. 4  illustrates another embodiment of an implant  150  of the present invention that does not require circumferential interruption of external screw threads. The implant  150  includes a threaded distal fixation member  152 , a threaded proximal fixation member  154 , and a flexible ligament member  156  interconnecting the distal  152  and the proximal fixation member  154 . Each of the distal  152  and proximal fixation member  154  has a major screw thread diameter  158  and a minor screw thread diameter  160 . The flexible ligament member  152  is seen to be positioned completely within the minor thread diameter  160  of both the distal  152  and the proximal fixation member  154 , thereby preventing damage to the flexible ligament member  156  when the implant  150  is threaded into mating internally threaded bone tunnels. The implant  150  is also seen to have a longitudinal axis  162  and an axial bore  164  through the proximal fixation member  154  and into the distal fixation member  152 , for sliding, removable engagement with an insertion tool. 
         [0041]      FIG. 5  illustrates an embodiment of a dual-diameter threaded implant  200  according to the present invention. The dual diameter implant  200  is constructed in a similar manner to the threaded implant  100  illustrated in  FIG. 1 , but the dual diameter implant  200  includes an externally threaded distal fixation member  202  that is smaller in diameter than an externally threaded proximal fixation member  204 . The dual diameter implant also includes an interconnecting flexible ligament member  206  extending between the distal  202  and the proximal fixation member  204 . The distal fixation member  204  has first screw threads  208  having a first major thread diameter  210 , a first minor thread diameter  212  and a first longitudinal thread spacing  214 . The first screw threads  208  are adapted to thread into a first internally threaded tunnel in bone  216 . The proximal fixation member  204  has second screw threads  218  having a second major thread diameter  220 , a second minor thread diameter  222  and a second longitudinal thread spacing  224 . The second screw threads  218  are adapted to thread into a second internally threaded tunnel in bone  226 . 
         [0042]    In an embodiment, the first major thread diameter  210  is less than or equal to the second minor thread diameter  222 . That is, the distal fixation device  202  is adapted to pass longitudinally and substantially without mechanical interference through the second internally threaded tunnel. Thus, the implant  200  can be passed distally directly through the second internally threaded tunnel  226  to the first internally threaded tunnel  216 , and threaded substantially simultaneously into the first  216  and the second internally threaded tunnel  226 . The second thread spacing  224  is substantially equal to the first thread spacing  214 , so that the distal  202  and the proximal fixation device  204  can be threaded into their respective threaded tunnels at the same axial rate with rotation of a single insertion tool engaged through an axial bore  228  through the proximal fixation member  204  and into the distal fixation member  202 . 
         [0043]      FIG. 6  illustrates yet another embodiment of a threaded implant  250  of the present invention. The implant  250  includes a distal fixation member  252  having a first external surface  254 , and a proximal fixation member  256  having a second external surface  258 . A flexible ligament member  260  extends between and interconnects the distal  252  and the proximal fixation member  256 . The implant  200  also includes an axis  262 , and an axial bore  264  through the proximal fixation member  256  and into the distal fixation member  252 . In an embodiment, the axial bore  264  extends distally completely through the distal fixation member  252 . One or both of the distal  252  and the proximal fixation member  254  includes one or more transverse bore  266  providing fluid communication between the axial bore  264  and one or both of the first  254  and the second external surface  258 , for delivering a fluid to a surgical site. The fluid may be an adhesive, a cement or filler material, a lubricant, a medicant such as pain medication or a healing stimulant, or another fluid. The fluid can be delivered by injection through a cannulated insertion tool positioned in the axial bore  264  and having transverse apertures aligned with the one or more transverse bore  266 . In one embodiment, the fluid is an adhesive that enhances the fixation of a fixation member in a bone tunnel. 
         [0044]    Another type of fixation member integrated with an implant of the present invention includes use of a toggling action to fix the implant in a bone tunnel.  FIG. 7  illustrates a toggle-type implant  300  having a distal fixation member  302  for fixing in a first bone tunnel  304 , a proximal fixation member  306  for fixing in a second bone tunnel  308 , and an interconnecting flexible ligament member  310  extending between the distal fixation member  302  and the proximal fixation member  306 . The implant  300  also includes a longitudinal bore  312  through the proximal fixation member  306  and into or through the distal fixation member  302 . The longitudinal bore  312  may be an axial bore, or may be radially displaced from a longitudinal axis  314 . In one embodiment, the bore  312  has a circular internal cross section. In another embodiment, the bore  312  has an internal cross section adapted for sliding, removable engagement with an external cross section of an insertion tool at one or more specific rotational angle about the axis  314 . 
         [0045]    The distal fixation member  302  includes a proximal-pointing edge  316  adapted to wedge against or dig into a wall  318  of the first bone tunnel  304  (toggling action) to fix the distal fixation member  302  in place after it is positioned in the first bone tunnel  304 . In an embodiment, the distal fixation member  302  is fixed in place by applying proximally-directed tension to the flexible ligament member  310 , to toggle the distal fixation member  302  in the first bone tunnel  304 . In one embodiment, the proximal fixation member  306  is externally threaded and the second bone tunnel  308  is correspondingly internally threaded. In another embodiment, the proximal fixation member  306  is a conventional bone block fixed in place in the second bone tunnel  308  by inserting an interference screw  320  between the bone block and a wall  322  of the second bone tunnel  308 , or by application of another fixation device. In yet another embodiment, the bore  312  through the proximal fixation member  306  is internally screw-threaded for engagement with an externally screw-threaded insertion tool, for applying tension to the flexible ligament member  310 . 
         [0046]      FIG. 8  through  FIG. 11  illustrate insertion tools for embodiments of the implants illustrated in  FIG. 1  through  FIG. 7 .  FIG. 8  illustrates a hexagonal cross section insertion tool  350  for the implant  100  of  FIG. 1  and  FIG. 2 . The insertion tool  350  has a proximal end  352  and a distal end  354 . The insertion tool  350  includes a proximal screwdriver-like handle  356  and a distal, elongated hexagonal external cross section shaft  358  adapted for sliding, removable engagement with the hexagonal internal cross section bore  132  illustrated in the proximal end view  130  of an embodiment of the implant  100 . The shaft  358  is fixedly attached to the handle  356 . The tool  350  is engaged with the implant  100  by passing the shaft  358  through the axial bore  128  through the proximal fixation member  112  and into the distal fixation member  108 . With the tool  350  engaged in the axial bore  128  in both the proximal  112  and the distal fixation member  108 , turning the handle  356  rotates both fixation members about the axis  106  simultaneously, for threading the implant  100  into a bone tunnel. 
         [0047]    When the distal  108  and proximal fixation member  112  is fully threaded into its respective first  110  and second tunnel  114 , as illustrated in  FIG. 1 , the tool  350  can be fully withdrawn from the bore  128 , leaving the implant  100  fixed in place. Alternatively, the tool  350  can be partially withdrawn from the bore  128  to disengage the shaft  358  from the distal fixation member  108  while remaining engaged with the proximal fixation member  112 . Rotating the handle  356  with the tool  350  in this partially withdrawn position adjusts tension on the flexible ligament member  116  by rotating the externally threaded proximal fixation member  112  in the internally threaded second tunnel  114 , while leaving the distal fixation member  108  stationary. When the tension adjustment is complete, the tool  350  can be fully withdrawn from the implant, leaving the tensioned implant  100  in place. 
         [0048]    A cannulated insertion tool can be used to deliver a fluid to an implant of the present invention and to an associated surgical site.  FIG. 9  illustrates a cannulated insertion tool  360  constructed in a similar manner to the hexagonal cross section insertion tool  350  illustrated in  FIG. 8 , with the addition of a cannulation  362  through the handle  356  and the shaft  358 . The cannulation  362  is open at the proximal end  352  and in various embodiments is open or closed at the distal end  354 . The cannulated tool  360  also includes one or more transverse aperture  364  through which a fluid introduced into the cannulation  362  from the proximal end  352  can be ejected from the cannulated tool  360 . In an embodiment, the one or more transverse aperture  364  is aligned with the one or more transverse bore  266  in the implant  250  illustrated in  FIG. 6 , for delivery of a fluid to a surgical site. In addition to a fluid, gels or powders may also be delivered thorugh the tool  360 . 
         [0049]      FIG. 10  illustrates an oval cross section insertion tool  370  that is similar in construction to the hexagonal cross section tool  350  of  FIG. 8 , except that the oval cross section tool  370  includes an oval external cross section distal shaft  372  adapted to removably engage the oval internal cross section bore  136  illustrated in  FIG. 3 , in the proximal end view  134  of an embodiment of the implant  100 .  FIG. 11  illustrates an insertion tool  380  for use with the toggle type implant  300  illustrated in  FIG. 7 . The insertion tool  380  has the proximal handle  356  and a distal shaft  382  for passing through the axial bore  312  in the proximal fixation member  306  and into the distal fixation member  302  of the toggle-type implant  300 . The insertion tool  380  is seen to also include a distal tip  384  adapted to engage with the axial bore  312  in the distal fixation member  302  while allowing the distal fixation member  302  to toggle. In an embodiment, the distal tip  384  is a distally tapered cone. In an embodiment, the shaft  382  includes a grasping member  386  for applying proximal tension to the implant  300 , for toggling the proximal fixation member  306  and for tensioning the flexible ligament member  310 . In an embodiment, the grasping member includes external screw threads for engagement with internal screw threads in the bore  312  through the proximal fixation member  306 . 
         [0050]    The distal shaft  382  has an external cross section adapted for engagement with the axial bore  312  through the proximal fixation device  306 . In one embodiment, the proximal fixation device  306  has external screw threads, the axial bore  312  through the proximal fixation device  306  has a hexagonal internal cross section, and the distal shaft  382  has a hexagonal external cross section releasably engageable with the axial bore  312 . In another embodiment, the proximal fixation device  306  is unthreaded and the distal shaft  382  has a circular external cross section. 
         [0051]    Any of the implants and tools of the present invention may be supplied to a surgeon as a kit for performing ACL surgery. Packaging the implant and the tool as a kit provides additional convenience for the surgeon and stable. In a kit, the implant may be pre-mounted on the tool to provide even greater convenience for the surgeon and a means for stably and protectively packaging the implant for shipment and storage. 
         [0052]    Referring now to  FIGS. 12-15 , the use of threaded implants and associated installation tools of the present invention in a surgical procedure is illustrated. Implants of the present invention may be used in the surgical repair of any articulated joint in a body, and have particular application to ACL repair surgeries in the human knee. Referring first to  FIG. 12 , prior to the installation of a threaded implant  400  of the present invention in a knee  402 , the knee  402  is prepared and positioned for ACL replacement surgery using conventional surgical tools and conventional surgical procedures. The implant  400  includes an externally threaded distal fixation member  404  having first external screw threads  406 , an externally threaded proximal fixation member  408  having second external screw threads  410 , and a flexible ligament member  412  extending between and interconnecting the distal fixation member  404  and the proximal fixation member  408 . The implant  400  also is seen to have an axial bore  414  for receiving an insertion tool  416 . The insertion tool  416  includes a proximal handle  418  and a distal shaft  420  for engagement with the axial bore  414 . The implant  400  is mounted on the tool  416  by passing the shaft  420  distally through the axial bore  414  in the proximal fixation member  408  and into the axial bore  414  in the distal fixation member  404 . The handle  418  can be rotated to rotate the tool  416  and the implant  400  mounted thereon. 
         [0053]    A tibial bone tunnel  422  through a tibia  424  and a femoral bone tunnel  426  in a femur  428  are prepared using conventional surgical tools and techniques. The tibial tunnel  422  and the femoral tunnel  426  share a common axis  430 . The tibial tunnel  422  is prepared with an internal diameter and internal screw threads adapted to engage with the second screw threads  410  on the proximal fixation member  408 . The femoral tunnel  426  is prepared with an internal diameter and internal screw threads adapted to engage with the first screw threads  406  on the distal fixation member  404 . The internal screw threads of the tibial  422  and the femoral tunnel  426  are formed using conventional thread forming techniques and tools. In an embodiment, the internal screw threads in each of the tibial  422  and femoral tunnel  426  are prepared using a threading tap. In one embodiment, the implant  400  includes distal and proximal fixation members of equal diameter, as described herein in association with embodiments of the implant  100  illustrated in  FIG. 1 . In this embodiment, the tibial tunnel  422  and the femoral tunnel  426  are each prepared with internal threads of a single thread specification with regard to major and minor thread diameter, and with regard to thread pitch. In another embodiment, the implant  400  includes distal and proximal fixation members having unequal diameters, as described herein in association with embodiments of the implant  200  illustrated in  FIG. 5 . In this embodiment, the tibial  422  and the femoral tunnel  426  are prepared with corresponding internal threads adapted to engage the respective proximal  408  and distal fixation member  404 . 
         [0054]    In  FIG. 12 , the implant  400  is illustrated mounted to the insertion tool  416  and partially threaded into the tibial tunnel  422 . The implant  400  is rotated about the axis  430  using the tool  416  to thread the distal fixation device  404  through the tibial tunnel  422 , after which the implant is pushed distally to an entrance  432  of the femoral tunnel  426 , as illustrated in  FIG. 13 . In an embodiment, the implant  400  includes distal and proximal fixation members having unequal diameters, as described herein in association with embodiments of the implant  200  illustrated in  FIG. 5 , and the distal fixation member  404  has a major thread diameter that is smaller than a minimum inner diameter of the threaded tibial tunnel  422 . In this embodiment, the distal fixation member  404  is passed distally through the tibial tunnel  422  and to the entrance  432  of the femoral tunnel  426  without engaging the internal threads of the tibial tunnel  422 . and without requiring rotation of the tool  416  and of the implant  400   
         [0055]    The distal fixation member  404  is then threaded into the femoral tunnel  426  simultaneously with the proximal fixation member  408  being threaded into the tibial tunnel  422 , as illustrated in  FIG. 14 . In an embodiment, the distal fixation member  404  includes one or more transverse bore, as described in association with the implant  250  illustrated in  FIG. 6 , and the insertion tool  416  includes one or more corresponding transverse aperture and a cannulation, as described herein in association with embodiments of the cannulated insertion tool  360  illustrated in  FIG. 9 . In this embodiment, a fluid may be injected into the surgical site through the tool  416  to provide medication or to enhance the fixation of the distal fixation member  404  in the femoral tunnel  426 . 
         [0056]    Referring now to  FIG. 15 , the tool  416  has been withdrawn proximally from the distal fixation member  404  positioned in the femoral tunnel  426 , while remaining engaged with the proximal fixation member  408  in the tibial tunnel  422 . In this position, rotation of the tool  416  rotates the proximal fixation member  408  within the tibial tunnel  422  to adjust tension on the flexible ligament portion  412  of the implant  400 . In an embodiment, the proximal fixation member xx includes one or more transverse bore, as described herein in association with embodiments of the implant  250  illustrated in  FIG. 6 , and the insertion tool  416  includes one or more corresponding transverse aperture and a cannulation, as described herein in association with embodiments of the cannulated insertion tool  360  illustrated in  FIG. 9 . In this embodiment, a fluid may be injected into the surgical site through the tool  416  to provide medication or enhance the fixation of the proximal fixation member  408  in the tibial tunnel  422 . The tool  416  is fully withdrawn proximally from the implant  400  to complete the installation of the implant  400 . 
         [0057]    Referring now to  FIGS. 16 and 17 , the use of a toggle-type implant  450  and an associated installation tool  452  of the present invention in a surgical procedure is illustrated. Referring first to  FIG. 16 , prior to the installation of the toggle-type implant  450  in a knee  454 , the knee  454  is prepared and positioned for ACL replacement surgery using conventional surgical tools and conventional surgical procedures. The implant  450  includes a toggle-type distal fixation member  456  as described herein in association with embodiments of the toggle-type implant  300  illustrated in  FIG. 7 . The implant  450  also includes a proximal bone block  458  and a flexible ligament member  460  interconnecting the distal fixation member  456  and the proximal bone block  458 . The implant  450  also is seen to have an axial bore  462  for receiving the insertion tool  452 . The insertion tool  452  includes a proximal handle  464  and a distal shaft  466  for engagement with the axial bore  462 . The implant  450  is mounted on the tool  452  by passing the shaft  420  distally through the axial bore  462  in the proximal fixation member  458  and into the axial bore  462  in the distal fixation member  456 . 
         [0058]    A tibial bone tunnel  468  through a tibia  470  and a femoral bone tunnel  472  in a femur  474  are prepared using conventional surgical tools and techniques. The tibial tunnel  468  and the femoral tunnel  472  share a common axis  476 .  FIG. 16  illustrates the implant  450  mounted to the tool  452  for passing through the tibial tunnel  468  and to the femoral tunnel  472 . In  FIG. 17 , the implant  450  is seen to have been passed through the tibial tunnel  468  and into the femoral tunnel  472 , tension has been applied to the flexible ligament member  460 , toggling the distal fixation member  456 , thereby fixing it in the femoral tunnel  472 . Also, tension has been applied to the flexible ligament member  460 , for fixation of the proximal bone plug  458  with an interference screw  478 . In an embodiment, the tension is applied through the grasping member  386  described herein in association with the tool  380  illustrated in  FIG. 11 . The tool  452  is withdrawn proximally from the implant  450  to complete the installation of the implant  450 . 
         [0059]    The implants, tools, and associated methods of the present invention have many advantages. The advantages include providing the surgeon with prepared, pre-sized implants for immediate placement in specified bone tunnels, saving the surgeon time and reducing the surgical skill required to perform an ACL repair surgery relative to conventional bone-tendon bone ACL repair surgeries where the surgeon often is required to manually shape oversized bone blocks to fit bone tunnels. Another advantage of the present invention is that the implant is self-fixating at one or both of the femoral and the tibial end, further reducing the labor and time required of the surgeon in fixating the implant. Further, the self-fixating implants reduce the number of foreign bodies left in the patient after surgery. By providing fixation members fabricated from the material of the bone blocks or their synthetic equivalents, the present invention provides not only fixation members that are integrated with an implant, but fixation members that are unitary with the material of the implant, making the implant a single part. Yet another advantage of the present invention is that it provides an implant that can be positioned in a joint and tensioned with a single insertion tool. Still another advantage of the present invention is that it provides a combination of an implant and a tool that can be used to conveniently inject a medicant or an adhesive selectively into a surgical site to enhance healing or fixation of the implant. 
         [0060]    Although this invention has been shown and described with respect to detailed embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the claimed invention.