Abstract:
A graft fixation device comprising: a graft separator comprising a distal end, a proximal end, a cavity disposed between the distal end and the proximal end, and at least one guide rib disposed radially outboard of the cavity and extending between the distal end and the proximal end; and an interference screw rotatably mountable within the cavity, the interference screw comprising a distal end, a proximal end, and a screw thread disposed intermediate thereof, the screw thread disposed radially outboard of at least a portion of the graft separator and radially inboard of the at least one rib.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATIONS 
       [0001]    This patent application: 
         [0002]    (i) is a continuation-in-part of pending prior U.S. patent application Ser. No. 13/528,680, filed Jun. 20, 2012 by Kelly G. Ammann for APPARATUS AND METHOD FOR LIGAMENT RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-0203), which patent application in turn:
       (a) claims benefit of prior U.S. Provisional Patent Application Ser. No. 61/498,663, filed Jun. 20, 2011 by Kelly G. Ammann for APPARATUS AND METHOD FOR ANATOMIC ACL RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-2 PROV); and   (b) claims benefit of prior U.S. Provisional Patent Application Ser. No. 61/638,848, filed Apr. 26, 2012 by Kelly G. Ammann for APPARATUS AND METHOD FOR ANATOMIC ACL RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-3 PROV);       
 
         [0005]    (ii) is a continuation-in-part of pending prior U.S. patent application Ser. No. 14/397,370, filed Oct. 27, 2014 by Jortek Surgical, Inc. and Kelly G. Ammann for APPARATUS AND METHOD FOR LIGAMENT RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-020304 PCT US), which patent application in turn:
       (a) claims benefit of International (PCT) Patent Application No. PCT/US13/024145, filed Jan. 31, 2013 by Jortek Surgical, Inc. for APPARATUS AND METHOD FOR LIGAMENT RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-020304 PCT); and   (b) is a continuation-in-part of pending prior U.S. patent application Ser. No. 13/528,680, filed Jun. 20, 2012 by Kelly G. Ammann for APPARATUS AND METHOD FOR LIGAMENT RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-0203), which in turn claims benefit of:
           (1) prior U.S. Provisional Patent Application Ser. No. 61/498,663, filed Jun. 20, 2011 by Kelly G. Ammann for APPARATUS AND METHOD FOR ANATOMIC ACL RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-2 PROV); and   (2) prior U.S. Provisional Patent Application Ser. No. 61/638,848, filed Apr. 26, 2012 by Kelly G. Ammann for APPARATUS AND METHOD FOR ANATOMIC ACL RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-3 PROV);   
               
 
         [0010]    (iii) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/018,327, filed Jun. 27, 2014 by Jortek Surgical, Inc. and Kelly G. Ammann for APPARATUS AND METHOD FOR ANATOMIC ACL RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-7 PROV); 
         [0011]    (iv) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/129,860, filed Mar. 8, 2015 by Jortek Surgical, Inc. and Kelly G. Ammann for APPARATUS AND METHOD FOR ANATOMIC ACL RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-8 PROV); 
         [0012]    (v) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/137,888, filed Mar. 25, 2015 by Jortek Surgical, Inc. and Kelly G. Ammann for APPARATUS AND METHOD FOR ANATOMIC ACL RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-9 PROV); and 
         [0013]    (vi) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/175,733, filed Jun. 15, 2015 by AnatomACL, LLC and Kelly G. Ammann for APPARATUS AND METHOD FOR ANATOMIC ACL RECONSTRUCTION (Attorney&#39;s Docket No. AMMANN-10 PROV). 
         [0014]    The nine (9) above-identified patent applications are hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0015]    This invention relates to medical apparatus and methods in general, and more particularly to medical apparatus and methods for reconstructing a ligament. 
       BACKGROUND OF THE INVENTION 
       [0016]    A ligament is a piece of soft, fibrous tissue that connects one bone to another bone in the skeletal system. Ligaments can often become damaged or injured. When damaged or injured, ligaments may tear, rupture or become detached from bone. The loss of a ligament can cause instability, pain and eventually increased wear on joint surfaces, which can lead to osteoarthritis. 
         [0017]    Various surgical techniques have been developed for ligament repair. The particular surgical technique used depends on the ligament that has been damaged and the extent of the injury. 
         [0018]    One ligament which is commonly injured is the anterior cruciate ligament (ACL). As seen in  FIG. 1 , the ACL  5  extends from the top of the tibia  10  to the side of the notch  15  which is located between the femoral condyles  20  of the femur  25 . 
         [0019]    Trauma to the knee can cause injury to the ACL. The ACL may become partially or completely torn.  FIG. 2  is a schematic view showing a torn ACL  5  in the left knee. An intact posterior cruciate ligament (PCL)  30  is shown behind the torn ACL  5 . 
         [0020]    A torn ACL reduces the stability of the knee joint and can result in pain, instability and excessive wear on the cartilage surfaces of the knee, eventually resulting in osteoarthritis. 
         [0021]    Several approaches are available for ACL reconstruction. One of the most commonly used ACL reconstruction techniques involves removal of most, or all, of the torn ACL, drilling bone tunnels in both the femur and the tibia, inserting a tissue graft (sometimes referred to herein as simply “the graft”) into the tibial and femoral tunnels so that the tissue graft extends across the interior of the knee joint in place of the native ACL, and securing the tissue graft in the femoral and tibial tunnels with interference screws or other fixation devices, so that the graft extends from the top of the tibia to the side of the femoral notch. 
         [0022]    More particularly, and looking now at  FIG. 3 , an aiming instrument  35  is aligned to tibia  10  and a tibial guide pin  40  (for guiding a cannulated drill, see below) is drilled into tibia  10 .  FIG. 3  illustrates a typical aiming instrument  35  for targeting the tibial guide pin  40  from the outside of tibia  10  to an exit point  45  on the tibial plateau  50  at the location corresponding to the insertion point of the natural ACL. Note that tibial guide pin  40  enters tibia  10  at an angle α relative to the plane of tibial plateau  50 , and exits the tibial plateau at the same angle α (relative to the plane of the tibial plateau). 
         [0023]    After tibial guide pin  40  has been appropriately drilled through the tibia, aiming instrument  35  is removed from the tibia, leaving tibial guide pin  40  in place. As seen in  FIG. 4 , a cannulated drill  55  (i.e., a drill with a center hole extending along the length of the drill) is slid over tibial guide pin  40  and drilled from the anteromedial surface of tibia  10 , through the tibia and into the joint space  60  of the knee.  FIG. 4  shows tibial guide pin  40  and cannulated drill  55  after cannulated drill  55  has been drilled through tibia  10 . In this way a tibial tunnel  70  may be formed in tibia  10 , with the tibial tunnel extending from the anteromedial surface of the tibia to the insertion point of the native ACL on the tibial plateau. 
         [0024]    A similar process may be followed for drilling into femur  25 , i.e., a femoral guide pin  65  may be inserted through tibial tunnel  70  and into femur  25  as shown in  FIG. 5 , and then a cannulated drill  75  may be drilled over the femoral guide pin  65  and into femur  25 . In this way a femoral tunnel  80  may be formed in femur  25 , with the femoral tunnel extending from the side of the femoral notch to part or all the way through the femur. Ideally, the joint-side mouth of femoral tunnel  80  is located at the insertion point of the native ACL on the femoral notch. 
         [0025]    The method described above and shown in  FIG. 5  is sometimes referred to as “transtibial femoral tunnel drilling”, since femoral tunnel  80  is drilled using access through tibial tunnel  70 . One problem with transtibial femoral tunnel drilling is that the location of the joint-side mouth of femoral tunnel  80  typically ends up being higher in the femoral notch  15  than the insertion point of the natural ACL, because access to the femur is limited by the location and size of tibial tunnel  70 . 
         [0026]    On account of the foregoing, an alternative method has been developed to create femoral tunnel  80 , i.e., by drilling the femoral tunnel using access through the “accessory medial portal”. More particularly, accessory medial portal drilling of the femoral tunnel involves drilling across the knee joint through a medial portal skin incision  85  such that the joint-side mouth of femoral tunnel  80  can be placed in a more anatomic position. In accessory medial portal drilling, and looking now at  FIG. 6 , femoral guide pin  65  is first passed through medial portal skin incision  85  and is then drilled into the desired anatomic location on the femur (i.e., the insertion point of the natural ACL on the femur). Then a cannulated drill  75  is slid over femoral guide pin  65  and drilled into femur  25  so as to form femoral tunnel  80 . Thus, femoral guide pin  65  and cannulated drill  75  enter through medial portal skin incision  85  and traverse across joint space  60  to the side of the femoral notch. As seen in  FIG. 6 , femoral guide pin  65  and cannulated drill  75  must enter in front of the adjacent femoral condyle  20  in order to prevent damaging the condyle. The knee quite often must be put into a state of deep flexion in order to reach the desired location (i.e., the insertion point of the natural ACL on the femur) and safely pass by the adjacent condyle  20  and tibial plateau  50 . 
         [0027]    Accessory medial portal drilling is generally considered to represent an improvement over transtibial femoral tunnel drilling in the sense that it can be used to create a more anatomic ACL reconstruction. 
         [0028]    After tibial tunnel  70  and femoral tunnel  80  have been created, the tissue graft is prepared. The tissue graft is typically harvested from the patient&#39;s own body tissue and may comprise hamstring tendons, quadriceps tendons, and/or patellar tendons. Alternatively, similar tissue grafts may be harvested from a donor and also include Achilles tendons, anterior tibialis tendons or other graft sources. Looking now at  FIG. 7 , a tissue graft  90  is prepared by creating one or more long tissue graft strands or graft bundles  95 , folding the graft over onto itself so as to create a folded section or loop  100 , and making measurements along the graft. Example measurements for adults are 30 mm of graft length for the portion of the graft that is to be inserted into femoral tunnel  80 , 27 mm to 30 mm for the portion of the graft that is intra-articular (i.e., inside the knee joint  60 ) and 35 mm for the portion that is to be positioned inside tibial tunnel  70 .  FIG. 7  shows tissue graft  90  folded over into two graft bundles  95  and a folded section or loop  100 , and the corresponding graft measurements. Sutures (whipstitches) are typically applied at the areas of the graft that will interface with the femoral and tibial tunnels so as to add additional strength to the tissue graft. As will hereinafter be discussed, the folded section or loop  100  of tissue graft  90  will interface with femoral tunnel  80  and the two opposite ends (i.e., portion of graft bundles  95 ) will be disposed in tibial tunnel  70 . 
         [0029]    As seen in  FIGS. 7 and 8 , graft tow sutures  105  are looped around the folded portion or loop  100  of graft  90 , forming a strand of sutures that can be used to pull graft  90  into place. More particularly, the free ends of graft tow sutures  105  are passed through tibial tunnel  70  and femoral tunnel  80 , e.g., with the assistance of a suture passing guide wire (not shown) of the sort well known in the art. Once the free ends of graft tow sutures  105  have been passed through the tibial and femoral tunnels, the free ends of graft tow sutures  105  can be pulled so as to pull graft  90  into the tibial and femoral tunnels.  FIG. 8  shows graft  90  folded over and in position to be pulled through tibial tunnel  70  and into femoral tunnel  80  using graft tow sutures  105 . The graft tow sutures  105  emanating from the distal end of femoral tunnel  80  are grasped with a clamp  110 , and clamp  110  and graft tow sutures  105  are used to pull graft  90  through tibial tunnel  70 , across the interior of the knee joint, and into femoral tunnel  80 . 
         [0030]    Once tissue graft  90  is in place, the individual graft bundles  95  making up the aggregate tissue graft  90  may be manipulated to approximate the anatomic positions of the native ACL. 
         [0031]    Advances in the research of ACL anatomy indicate that there are two primary bundles that make up the natural ACL, the anteromedial bundle and the posterolateral bundle. More particularly, and looking now at  FIG. 9 , the anteromedial bundle  115  and the posterolateral bundle  120  are also referred to as the “AM” bundle and the “PL” bundle. The particular name of the ligament bundle refers to its point of origin on tibial plateau  50 , i.e., AM bundle  115  originates anteromedially and PL bundle  120  originates posterolaterally (relative to each other on the tibial plateau). As seen in  FIG. 9 , the AM and PL bundles are roughly parallel to each other when the knee is in full extension. 
         [0032]    However, when the knee is fully flexed, and looking now at  FIG. 10 , AM bundle  115  and PL bundle  120  “cross” each other. As such, a true anatomic reconstruction of the ACL must place the graft bundles  95  into the proper femoral and tibial positions in order to achieve the natural kinematic motion of the ACL and the knee joint. 
         [0033]    Thus, in an ACL reconstruction, it is desired to manipulate graft  90  into position such that the two graft bundles  95  (see  FIGS. 7 and 8 ) making up the aggregate tissue graft  90  are located in the approximate positions of the natural AM and PL bundles of the native ACL. It has been demonstrated in biomechanical tests that this construct results in a more stable ACL reconstruction. 
         [0034]    After graft  90  is inserted into the tibial and femoral tunnels, preferably with graft bundles  95  disposed so as to mimic the natural AM and PL bundles of the native ACL, fixation screws (also known as interference screws) are inserted into the femoral and tibial bone tunnels so as to secure graft  90  to femur  25  and tibia  10 . More particularly, and looking now at  FIG. 11 , the femoral portion of graft  90  is first fixed into place by inserting a femoral interference screw  125  through the medial portal skin incision  85 , advancing femoral interference screw  125  across the interior of the joint, and then screwing femoral interference screw  125  into femoral tunnel  80  e.g., with a driver  127 . Femoral interference screw  125  squeezes graft  90  tightly against the wall of femoral tunnel  80 . As femoral interference screw  125  is tightened into place, the femoral interference screw creates an interference fit between femoral tunnel  80 , graft  90  and femoral interference screw  125 . 
         [0035]      FIG. 12  shows the femoral fixation in place, with AM bundle  95 AM of graft  90  approximating the anatomic position of the native AM bundle and PL bundle  95 PL of graft  90  approximating the anatomic position of the native PL bundle. 
         [0036]    Finally, and looking now at  FIG. 13 , a tibial interference screw  130  is screwed into tibial tunnel  70  so as to secure graft  90  in tibial tunnel  70 . 
         [0037]    The foregoing technique has been used for many years for the reconstruction of a damaged or injured ACL. This technique has generally been successful, but it does have some limitations. Typically, the location of graft  90  around the perimeter of interference screws  125 ,  130  is uncontrolled because the graft bundles  95  rotate as the interference screws are inserted. As a result, it is difficult to set the interference screws while keeping AM bundle  95 AM and PL bundle  95 PL in their correct anatomical positions. 
         [0038]    Furthermore, on the tibial side, tibial interference screw  130  may skive off the centerline of tibial tunnel  70  as tibial interference screw  130  is screwed into place. As a result, the AM and PL bundles  95 AM,  95 PL may bunch up and migrate to one side of tibial tunnel  70 . This occurrence creates a non-anatomic reconstruction which may also result in reduced pull-out strength and can contribute to changes in the natural motion of the knee. Clinically, this occurrence may contribute to tunnel widening where the tibial interference screw  130  skives off to one side of the tibial tunnel and the AM and PL bundles  95 AM,  95 PL are bunched up on the other side of the tibial tunnel, causing the softer cancellous bone inside the tibia to collapse.  FIG. 14  illustrates how the off-center disposition of tibial interference screw  130  can result in a non-anatomic reconstruction: the AM and PL bundles  95 AM,  95 PL may not be located in their correct anatomic positions; at various degrees of knee flexion, one of the bundles may become excessively slack; the overall strength of the construct may be reduced; and natural knee motion may be altered, contributing to the development of osteoarthritis or an increase in the need for subsequent revision surgery. 
         [0039]    A closer analysis of how the tibial and femoral tunnels  70 ,  80  are formed, and a closer look at the anatomic insertions of graft  90  into the femur and tibia, illustrate how graft fixation can be configured to produce a more anatomic reconstruction. 
         [0040]    Because cannulated drill  75  enters the surface of femur  25  at an angle ( FIGS. 5 and 6 ), the entrance of femoral tunnel  80  is elliptical ( FIG. 15 ). This elliptical shape is not due to poorly manufactured drills, poor surgical technique, etc. It is the normal result of drilling a hole into a surface while the drill is set at a non-perpendicular angle to the surface. This is illustrated in  FIG. 15 , which shows the outline of femoral tunnel  80  when looking directly into the bone surface. 
         [0041]    Similarly, when cannulated drill  55  exits tibial tunnel  70  and enters the interior of the joint at an angle ( FIG. 4 ), the shape of the tunnel opening is elliptical at the tibial plateau  50  ( FIG. 16 ). 
         [0042]    This elliptical shape of the joint-side entrance of femoral tunnel  80  and at the joint-side exit of tibial tunnel  70  has been documented in biomechanical studies. 
         [0043]    For reference, the normal anatomic ACL insertion shape, or morphology, on the surface of the femur is shown in  FIG. 17 . The AM and PL bundles  115 ,  120  are shown in typical anatomic locations. 
         [0044]    Similarly, the normal anatomic ACL insertion shape on the surface of the tibia are shown in  FIG. 18 . The AM and PL bundles  115 ,  120  are shown in typical anatomic locations. 
         [0045]    Typical interference screws fixate graft  90  along the length of the interference screws, with the graft located between the interference screw and the side wall of the bone tunnel. See  FIG. 19 , which shows femoral interference screw  125  securing graft  90  to femur  25 . However, as discussed above and as shown in  FIG. 14 , the two graft bundles  95  of graft  90  do not typically lie in the true anatomic AM and PL bundle locations because graft bundles  95  rotate with the rotation of the interference screws before coming to rest in their final fixed position. 
         [0046]    In a similar fashion, graft bundles  95  may rotate or be compressed into non-anatomic positions at the entrance of tibial tunnel  70 . 
         [0047]    In addition, with respect to tibial fixation, the curved taper at the tip of an interference screw lies near the joint-side exit of tibial tunnel  70 , and this distal taper of the interference screw creates some laxity of graft  90 .  FIG. 20  shows the AM graft bundle  95 AM and the PL graft bundle  95 PL shown approximately in their anatomic positions. The area at the distal end of interference screw  130  shows how graft  90  is loosely fixated in the area near the distal tip of the interference screw. This loose fixation of graft  90  may contribute to problems such as the so-called “windshield wiper effect”, where graft  90  sweeps across the opening of the bone tunnel, thereby causing abrasion to the graft and to the bone tunnel; and joint laxity due to incomplete fixation of the graft into its anatomic position. 
         [0048]    Thus there are problems with standard interference screw fixation: the graft bundles may come to rest around the interference screw in non-anatomic locations, resulting in a biomechanical construct that does not replicate the native anatomy; there is a lack of complete fixation of the graft at the opening of the bone tunnel to the joint space; and the unsecured graft in the elliptical opening of the bone tunnel may contribute to the windshield wiper effect, biomechanical instability and tunnel widening. 
         [0049]    Another type of graft fixation in common use is sometimes referred to as suspensory fixation. In suspensory fixation, and looking now at  FIG. 21 , graft  90  is passed through a fabric loop  135  which is, in turn, secured to a button  140 . Button  140 , loop  135  and graft  90  are inserted into a femoral bone tunnel  80 , and button  140  is “flipped” outside the distal bone cortex so as to suspend the graft in the femoral tunnel. In one variation of this technique, and as is shown in  FIG. 21 , anatomic reconstruction is effected by creating two femoral bone tunnels  80 , one for the AM bundle  95 AM and one for the PL bundle  95 PL. 
         [0050]    As also seen in  FIG. 21 , a similar approach may be used on the tibial side. 
         [0051]    Furthermore, if desired, and as is also shown in  FIG. 21 , an interference screw  142  may also be used to enhance femoral or tibial fixation. 
         [0052]    In this type of ligament reconstruction, the grafts  90  are freely suspended in the femoral tunnel(s)  80 . Micro-movement of graft  90  due to loading and unloading of the graft tissue may contribute to tunnel widening and loss of fixation. Also, the location of the graft bundles  95  in the femoral tunnel(s) is to some extent uncontrolled, inasmuch as the graft bundles are free to rotate and translate laterally, and to a smaller extent axially, within the femoral tunnel(s). 
         [0053]    The previously-described approaches illustrate much of the current practice of ACL reconstruction. Current approaches do not lend themselves to creating a highly accurate anatomic reconstruction. The current devices can result in constructs that do not fully stabilize the graft. The subsequent motion of the graft may contribute to tunnel widening, loss of graft tension, loss of knee stability and may result in the need for subsequent revision surgery. 
       SUMMARY OF THE INVENTION 
       [0054]    A new and improved approach for ACL reconstruction is disclosed herein. The object of the present invention is to secure the graft bundles to the femur and the tibia such that they are oriented and positioned in the true anatomic locations of the native ACL insertions. This orientation and positioning results in fixation of the graft AM bundle and the graft PL bundle near the natural anatomic footprints of the native AM bundle and native PL bundle at the tibia and femur. Furthermore, the graft AM bundle and the graft PL bundle are more effectively secured within the femoral and tibial bone tunnels, eliminating micro-movement within the bone tunnels. 
         [0055]    In one preferred form of the present invention, there is provided a graft fixation device comprising: 
         [0056]    a graft separator comprising a distal end, a proximal end, a cavity disposed between said distal end and said proximal end, and at least one guide rib disposed radially outboard of said cavity and extending between said distal end and said proximal end; and 
         [0057]    an interference screw rotatably mountable within said cavity, said interference screw comprising a distal end, a proximal end, and a screw thread disposed intermediate thereof, said screw thread disposed radially outboard of at least a portion of said graft separator and radially inboard of said at least one rib. 
         [0058]    In another preferred form of the present invention, there is provided a tibial graft separator for separating the AM bundle and PL bundle of an ACL graft for disposition in a notched tibial tunnel, wherein the notched tibial tunnel comprises a bore and a pair of diametrically-opposed notches opening on the bore and extending diametrically outboard of the bore, said tibial graft separator comprising: 
         [0059]    an elongated planar body having a distal end, a proximal end, a first side extending from said distal end to said proximal end, and a second side extending from said distal end to said proximal end; and 
         [0060]    a raised rim extending along said first side and said second side; 
         [0061]    wherein said tibial graft separator is sized to be received within said notched tibial tunnel, with a first portion of said raised rim being disposed in one of the pair of diametrically-opposed notches, a second portion of said raised rim being disposed in the other of the pair of diametrically-opposed notches, and with said elongated planar body bifurcating the bore of the notched tibial tunnel into two passageways. 
         [0062]    In another preferred form of the present invention, there is provided a femoral graft separator for separating the AM bundle and PL bundle of an ACL graft for disposition in a notched femoral tunnel, wherein the notched femoral tunnel comprises a bore and a pair of diametrically-opposed notches opening on the bore and extending diametrically outboard of the bore, said femoral graft separator comprising: 
         [0063]    an elongated planar body having a distal end, a proximal end, a first side extending from said distal end to said proximal end, and a second side extending from said distal end to said proximal end, said first and second sides having a taper; and 
         [0064]    a shaft connected to said proximal end of said elongated planar body; 
         [0065]    said elongated planar body and said shaft being cannulated; 
         [0066]    wherein said femoral graft separator is sized to be received within said notched femoral tunnel, with a portion of said first side being disposed in one of the pair of diametrically-opposed notches, a portion of said second side being disposed in the other of the pair of diametrically-opposed notches, and with said elongated planar body bifurcating the bore of the notched femoral tunnel into two passageways. 
         [0067]    In another preferred form of the present invention, there is provided a femoral graft separator for separating the AM bundle and PL bundle of an ACL graft for disposition in a notched femoral tunnel, wherein the notched femoral tunnel comprises a bore and a pair of diametrically-opposed notches opening on the bore and extending diametrically outboard of the bore, said femoral graft separator comprising: 
         [0068]    a body having a distal end, a proximal end, a first projection extending distally from said distal end of said body, and a second projection extending distally from said distal end of said body; and 
         [0069]    a shaft connected to said proximal end of said body; 
         [0070]    said body and said shaft being cannulated; 
         [0071]    wherein said femoral graft separator is sized to be received within said notched femoral tunnel, with said first projection being disposed in one of the pair of diametrically-opposed notches, said second projection being disposed in the other of the pair of diametrically-opposed notches, and with said body bifurcating the bore of the notched femoral tunnel into two passageways. 
         [0072]    In another preferred form of the present invention, there is provided a method for securing a graft in a bone tunnel, wherein the graft comprises a first graft bundle and a second graft bundle, said method comprising: 
         [0073]    forming a notched bone tunnel comprising a bore and a pair of diametrically-opposed notches opening on the bore and extending diametrically outboard of the bore; 
         [0074]    advancing the graft into the notched bone tunnel; 
         [0075]    advancing a graft bundle separator into the notched bone tunnel so as to bifurcate the bore of the notched bone tunnel into two passageways and to separate the first graft bundle and the second graft bundle, with the first graft bundle being in one of the two passageways and the second graft bundle being in the other of the two passageways, and advancing an interference screw into the notched bone tunnel so as to secure the first and second graft bundles to the side wall of the notched bone tunnel. 
         [0076]    In another preferred form of the present invention, there is provided a method for reconstructing a ligament, said method comprising: 
         [0077]    providing a graft comprising a first graft bundle and a second graft bundle; 
         [0078]    forming a first notched bone tunnel in a first bone, the first notched bone tunnel comprising a bore and a pair of diametrically-opposed notches opening on the bore and extending diametrically outboard of the bore, and forming a second notched bone tunnel in a second bone, the said notched bone tunnel comprising a bore and a pair of diametrically-opposed notches opening on the bore and extending diametrically outboard of the bore; 
         [0079]    advancing the graft through the first notched bone tunnel and into the second notched bone tunnel; 
         [0080]    advancing a graft bundle separator into the second notched bone tunnel so as to bifurcate the bore of the second notched bone tunnel into two passageways and to separate the first graft bundle and the second graft bundle, with the first graft bundle being in one of the two passageways and the second graft bundle being in the other of the two passageways, and advancing an interference screw into the second notched bone tunnel so as to secure the first and second graft bundles to the side wall of the second notched bone tunnel; and 
         [0081]    advancing a graft bundle separator into the first notched bone tunnel so as to bifurcate the bore of the first notched bone tunnel into two passageways and to separate the first graft bundle and the second graft bundle, with the first graft bundle being in one of the two passageways and the second graft bundle being in the other of the two passageways, and advancing an interference screw into the first notched bone tunnel so as to secure the first and second graft bundles to the side wall of the first notched bone tunnel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0082]    These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein: 
           [0083]      FIG. 1  is a schematic view showing the interior of a knee joint, including the native ACL; 
           [0084]      FIG. 2  is a schematic view showing the interior of a knee joint, including a damaged or injured ACL; 
           [0085]      FIGS. 3-8  are schematic views showing bone tunnels being formed in the tibia and femur, and a graft being inserted into the bone tunnels; 
           [0086]      FIGS. 9 and 10  are schematic views showing details of the construction and biomechanics of the ACL as the knee moves from extension to flexion; 
           [0087]      FIGS. 11-13  are schematic views showing a graft being secured in femoral and tibial tunnels using interference screws; 
           [0088]      FIG. 14  is a schematic view showing how a graft may be secured off-center within a bone tunnel when using a conventional interference screw; 
           [0089]      FIG. 15  is a schematic view showing how a femoral tunnel typically has an elliptical configuration at the joint-side mouth of the femoral tunnel; 
           [0090]      FIG. 16  is a schematic view showing how a tibial tunnel typically has an elliptical configuration at the joint-side mouth of the tibial tunnel; 
           [0091]      FIG. 17  is a schematic view showing the natural insertion of the ACL on the femur; 
           [0092]      FIG. 18  is a schematic view showing the natural insertion of the ACL on the tibia; 
           [0093]      FIG. 19  is a schematic view showing how the AM and PL graft bundles of the ACL may rotate with an interference screw; 
           [0094]      FIG. 20  is a schematic view showing how fixation of a graft in a tibial tunnel with an interference screw may lead to the so-called “windshield wiper effect”; 
           [0095]      FIG. 21  is a schematic view showing a suspensory fixation of a graft in femoral and tibial tunnels; 
           [0096]      FIGS. 22-25  are schematic views showing creation of a femoral tunnel in accordance with the present invention; 
           [0097]      FIGS. 26 and 27  are schematic views showing creation of a tibial tunnel in accordance with the present invention; 
           [0098]      FIGS. 28-31  are schematic views showing the femoral tunnel being notched and thereafter drilled through to the distal side of the femur; 
           [0099]      FIGS. 32-36  are schematic views showing the tibial tunnel being notched; 
           [0100]      FIGS. 37-40  are schematic views showing a graft being inserted into tibial and femoral tunnels using a tibial graft separator and a femoral graft separator; 
           [0101]      FIG. 41  is a schematic view showing an alternative approach for preparing a graft; 
           [0102]      FIGS. 42 ,  43 ,  43 A and  44 - 47  are schematic views showing the graft of  FIG. 41  being inserted into a femoral tunnel; 
           [0103]      FIGS. 47A ,  48 - 58  and  59 A are schematic views showing a femoral fixation device formed in accordance with the present invention; 
           [0104]      FIGS. 59B ,  60 A,  60 B and  61 - 63  are schematic views showing a femoral fixation device being inserted into a femoral tunnel; 
           [0105]      FIGS. 64-72  are schematic views showing a tibial fixation device being inserted into a tibial tunnel; 
           [0106]      FIGS. 73 and 74  are schematic views showing a graft ligament reconstruction performed in accordance with the present invention; and 
           [0107]      FIGS. 75A ,  75 B and  76 - 78  are schematic views showing alternative forms of the femoral fixation device and the tibial fixation device. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Bone Tunnel Formation 
       [0108]    In accordance with the present invention, and looking now at  FIG. 22 , the femoral tunnel is prepared by placing a femoral guide pin  145  into the anatomic location of the native femoral ACL insertion. It is desirable for femoral guide pin  145  to enter the intercondylar notch  15  at an angle, to avoid the adjacent medial condyle  20  as well as the tibial plateau  50 . 
         [0109]    From a top view ( FIG. 23 ), with the knee in 90° of flexion, the path of femoral guide pin  145  is shown as it passes by the medial condyle  20  and enters the medial aspect of the intercondylar notch  15 . Femoral guide pin  145  enters at an angle β from the sagittal plane. The angle β must be great enough to ensure that femoral guide pin  145  passes by the adjacent medial condyle  20  without contacting the medial condyle. 
         [0110]    Placement of femoral guide pin  145  in this manner allows access to the true anatomic insertion point of the native ACL. 
         [0111]    A cannulated drill  150  is then slid over femoral guide pin  145 , advanced through medial portal skin incision  85 , past the medial condyle  20  and tibial plateau  50  and into the anatomic location of the native femoral ACL insertion, as shown in  FIG. 24 . 
         [0112]    The femoral tunnel  80  is then drilled using cannulated drill  50  and the result is a circular bore hole with an elliptical tunnel entrance, as shown in  FIG. 25 . This portion of the technique is generally similar to that which was discussed above, except that it is completed with an understanding that, with the present invention, and as will hereinafter be discussed in further detail, the angled entrance of femoral tunnel  80  contributes in a positive manner in creating a more anatomic femoral fixation. As such, the surgeon does not try to “straighten out” the femoral tunnel so as to achieve a circular entrance, but rather may actually slightly increase the angle β so as to achieve the more anatomic elliptical entrance (i.e., to match the native anatomic insertion of the natural ACL on the femur). Furthermore, it is helpful, when using the femoral fixation approach described below, to make certain adjustments to the drilling of the femoral tunnel. For one thing, the length of the femoral tunnel should be drilled 5 mm-10 mm longer than the anticipated femoral fixation length. This allows for the graft to expand into the distal end of the femoral tunnel as the fixation squeezes the graft tightly up against the side wall of the femoral tunnel. Also, on the femoral side, it is useful to drill the tunnel 0.5 mm-1.0 mm larger than the measured graft diameter. 
         [0113]    Similarly, and looking now at  FIG. 26 , the tibial tunnel is prepared by first drilling a tibial guide pin  155  (with the aid of a drill guide  160 ) through the anteromedial surface of the tibia, exiting through the anatomic center of the desired ACL insertion on tibial plateau  50  (i.e., in the manner previously described). The tibial drilling angle, α 2 , can be smaller than the traditional tibial drilling angle α in a traditional ACL reconstruction, because the elliptical/oval nature of the tibial tunnel exit on the tibial plateau contributes to the anatomic reconstruction of the present invention. This can be a significant advantage over the prior art, since a shorter tibial tunnel (a consequence of drilling at angle α 2  rather than at angle α) means less trauma to the tibia and more space on the anteromedial surface of the tibia below the tibial tunnel (which may be used for other surgical procedures, if needed). Drill guide  160  is removed and a cannulated drill (not shown in  FIG. 26 , but generally similar to cannulated drill  150  discussed above) is placed over tibial guide pin  155 . This cannulated drill is then drilled from the outside of the tibia through to the tibial plateau  50 , passing through the natural anatomic footprint of the native ACL insertion.  FIG. 27  illustrates the effect of drilling at the angle α 2  (rather than at the conventional angle α) at the exit of the tibial tunnel onto tibial plateau  50 . The exit of tibial tunnel  70  onto tibial plateau  50  becomes a more elongated ellipse, increasing the footprint of the graft insertion and contributing to a more anatomic reconstruction, as will hereinafter be discussed in further detail. 
         [0114]    The present invention comprises a further unique step in the preparation of the femoral and tibial bone tunnels. More particularly, and looking now at  FIG. 28 , after creating the anatomically-placed tibial and femoral tunnels  70 ,  80 , each of the tunnels is “notched” (e.g., with two diametrically-opposed notches) using a notching instrument (or “notcher”)  165  that is designed to closely and specifically match the pre-drilled tunnel while adding diametrically-opposed notches to the tunnel. These notches are placed at the natural bifurcation (split) locations of the AM and PL bundles  95 AM,  95 PL (i.e., the plane of the two diametrically-opposed notches is aligned with the natural bifurcation plane of the AM and PL bundles  95 AM,  95 PL). In the case of femoral tunnel  80 , femoral guide pin  145  is retained in the femur after the femoral tunnel drilling has been completed. Notcher  165  is cannulated. Notcher  165  is slid over the femoral guide pin  145  and brought into proximity with femoral tunnel  80 , as shown in  FIG. 28 . 
         [0115]    In one preferred form of the present invention, and as seen in  FIGS. 28 and 29 , notcher  165  comprises a cylindrical tip  170  that closely matches the diameter of femoral tunnel  80 . Two stepped protrusions  175  emanate from opposing sides of cylindrical tip  170 , creating a form of broaching tool. The center opening (or cannulation)  180  of notcher  165  slides over femoral guide pin  145  so as to center notcher  165  in femoral tunnel  80 . 
         [0116]    As seen in  FIG. 30 , notcher  165  is driven into the femur, preferably to the depth of the drilled femoral bone tunnel, by hand or with a mallet, forming channels (or notches)  185  along the femoral bone tunnel  80 . See  FIG. 30 . 
         [0117]    After notching the femoral tunnel, notcher  165  is removed from femoral guide pin  145  and then a smaller 4.5 mm to 5.0 mm cannulated drill  190  is passed over femoral guide pin  145  and drilled through the distal cortex of femur  25 . This extends the distal end of femoral tunnel  180  all the way through femur  25  for later use. See  FIG. 31 . 
         [0118]    On the tibial side, similar notches are created for tibial tunnel  70 . However, in the absence of an emplaced tibial guide pin to support notcher  165  on the tibial side (i.e., tibial guide pin  40  is removed from the tibia after tibial tunnel  70  is formed, since there is no grounding for the distal end of tibial guide pin  40  after the tibial tunnel is drilled completely through to tibial plateau  50 ), and considering the hardness of the cortical bone surface on the anteromedial surface of tibia  10 , two holes (see below) are drilled (using a tibial notcher drill guide and drill, see below) in the approximate area of the desired tibial notches and these two holes are then used to guide notcher  165  as the notches are formed in the tibia for tibial tunnel  70 . 
         [0119]    The tibial notcher drill guide  195  and drill  200  are shown in  FIG. 32 . 
         [0120]    As seen in  FIG. 33 , tibial notcher drill guide  195  is inserted into the previously-drilled tibial tunnel  70 . The two channels  205  (only one of which is seen in  FIGS. 32 and 33 ) on the side of tibial notcher drill guide  195 , which connect with openings  210  formed on the proximal end of tibial notcher drill guide  195 , are aligned with the location of the desired anatomic split which is to be achieved between the AM and PL bundles. Drill  200  is then used to drill into one opening  210  and along channel  205  on one side of tibial notcher drill guide  195 , and to drill into the other opening  210  on the other side of tibial notcher drill guide  195  and along the channel  205  on the other side of tibial notcher drill guide  195 , thereby forming two side holes  215  (see  FIG. 34 ) which intersect with the larger tibial tunnel  70  and provide a guide for the stepped protrusions  175  of notcher  165  when notcher  165  is used to form notches in the tibial tunnel (see below). A larger threaded hole  220  ( FIG. 33 ) at the lower middle part of tibial notcher drill guide  195  may be used to secure a threaded tool to tibial notcher drill guide  195 , to aid in the insertion or removal of tibial notcher drill guide  195  from tibial tunnel  70 .  FIG. 33  shows tibial notcher drill guide  195  in place and drill  200  about to make one of the side holes  215  for notcher  165 . Side holes  215  are preferably drilled through the tibia up to the subchondral bone, without entering the joint space. 
         [0121]    The tibia, with tibial tunnel  70  and side holes  215  for receiving notcher  165 , is shown in  FIG. 34 . 
         [0122]    Then, and looking now at  FIG. 35 , notcher  165  is brought into proximity with tibial tunnel  70 , the stepped protrusions  175  of notcher  165  are aligned with side holes  215  in the tibia, and the notcher is driven along the tibial tunnel, forming channels (or notches)  225  along the tibial tunnel, in a manner similar to the manner in which notches  185  were formed along the femoral tunnel. Notcher  165  is generally not driven all the way through the tibia and into the joint space, but is only driven up to the subchondral bone surface (i.e., notcher  165  is driven into tibia  10  to the same depth that the two side holes  215  are drilled into tibia  10 ). This creates a subchondral bone surface at the distal ends of tibial notches  225  for the subsequently-placed tibial fixation device (see below) to rest on, thus increasing the strength of the tibial fixation. 
         [0123]      FIG. 35  shows notcher  165  entering tibial tunnel  70  in order to create the tibial tunnel notches  225 . 
         [0124]    The notched tibial tunnel (i.e., the tibial tunnel  70  with diametrically-opposed notches  225 ) is shown in  FIG. 36 . 
       Graft Insertion 
       [0125]    After tibial tunnel  70  has been notched (i.e., by forming diametrically-opposed notches  225  along tibial tunnel  70 ) and after femoral tunnel  80  has been notched (i.e., by forming diametrically-opposed notches  185  along femoral tunnel  80 ), graft  90  is inserted through tibial tunnel  70  and into femoral tunnel  80 . 
         [0126]    1. First Approach for Graft Insertion 
         [0127]    In a manner that is similar to the approach described above, graft  90  is folded over such that two graft bundles  95  comprise the aggregate graft  90 , and graft tow sutures  105  are looped around graft  90  at folded section  100  (i.e., where the graft is folded over). See  FIG. 7 . 
         [0128]    Next, a guide pin (not shown), having an eyelet (not shown) for passing sutures, is inserted through medial portal skin incision  85 , through joint space  60  and through femoral tunnel  80 . The suture-carrying guide pin exits through the skin opposite the distal end of femoral tunnel  80 . The passing sutures carried through the femoral tunnel are then grasped (with a hemostat) and the guide pin is withdrawn. Then graspers (not shown) are inserted through tibial tunnel  70 , into joint space  60  and used to grasp the passing sutures emerging on the joint side of femoral tunnel  80 . These graspers are then used to pull the passing suture emerging from the joint side of femoral tunnel  80  across joint space  60  and down through tibial tunnel  70  until the passing sutures emerge on the anteromedial side of tibia  10 . At this point, these passing sutures extend from the anteromedial side of tibia  10 , up through tibial tunnel  70 , across joint space  60 , through femoral tunnel  80  and exits through the skin opposite the distal end of femoral tunnel  80 . 
         [0129]    These passing sutures are then used to tow graft  90  through tibial tunnel  70 , through joint space  60  and into femoral tunnel  80 , i.e., by tying graft tow sutures  105  to the passing sutures emerging from tibial tunnel  70 , and then pulling on the passing sutures emerging from femoral tunnel  80 . 
         [0130]    In order to ensure that graft bundles  95  of graft  90  are disposed in their anatomically correct locations within tibial tunnel  70  and femoral tunnel  80 , a tibial graft separator  230  ( FIGS. 37 and 38 ) and a femoral graft separator  235  ( FIGS. 37 and 39 ) are used. 
         [0131]    As seen in  FIGS. 37 and 38 , tibial graft separator  230  is provided for aligning graft bundles  95  relative to tibial tunnel  70 . More particularly, tibial graft separator  230  comprises a rim  240  extending around the perimeter of tibial graft separator  230 . Tibial graft separator  230  is sized to fit into notches  225  formed in tibial tunnel  70 , with the tibial graft separator bifurcating tibial tunnel  70  into two passageways. The portion of tibial graft separator  230  which extends between rims  240  is thinner, providing spaces for allowing graft bundles  95  of graft  90  to pass through tibial tunnel  70  (the graft bundle  95 AM being located on one side of the tibial graft separator and the graft bundle  95 PL being located on the other side of the tibial graft separator). If desired, tibial graft separator  230  may include a label (e.g., “AM”) on one side of tibial graft separator  230  in order to remind the surgeon of the AM bundle side, and tibial graft separator  230  may include another label (e.g., “PL”) on the other side of tibial graft separator  230  in order to remind the surgeon of the PL bundle side. In one preferred form of the present invention, tibial graft separator  230  comprises two small holes  245  for allowing temporary suture fixation of the graft  90  to tibial graft separator  230  (if necessary), and a larger hole  250  to aid in removing tibial graft separator  230  from tibial tunnel  70  (if necessary). 
         [0132]    As seen in  FIGS. 37 and 39 , femoral graft separator  235  preferably comprises side protrusions  255  for tracking femoral graft separator  235  within notches  185  of femoral tunnel  80 , such that the femoral graft separator can bifurcate femoral tunnel  80  into two passageways. In one preferred form of the present invention, femoral graft separator  235  is cannulated with a central bore  260 , whereby to permit passing femoral graft separator  235  over a guide wire if desired. 
         [0133]    Looking now at  FIG. 37 , after passing sutures have been extended from the anteromedial side of tibia  10 , through tibial tunnel  70 , across joint space  60  and through femoral tunnel  80 , tibial graft separator  230  is introduced between graft bundles  95 , and aligned with notches  225  of tibial tunnel  70 . Tibial graft separator  230  is placed between graft bundles  95  so that one of the graft bundles,  95 AM, is in the position of the natural AM bundle and the other of the graft bundles,  95 PL, is in the position of the natural PL bundle, with the sides of tibial graft separator  230  aligned with tibial tunnel notches  225 . Then, using the passing sutures secured to graft tow sutures  105 , and advancing tibial graft separator  230  in conjunction with graft  90 , graft  90  is pulled into tibial tunnel  70 . It will be appreciated that as graft  90  is pulled up through tibial tunnel  70 , the advancing tibial graft separator  230  will act as a tunnel bifurcator, ensuring that graft bundle  95 AM is in the position of the natural AM bundle and the graft bundle  95 PL is in the position of the natural PL bundle. 
         [0134]    Still looking now at  FIG. 37 , after the distal end of graft  90  has been drawn up through tibial tunnel  70  and into joint space  60 , a femoral guide wire  270  (approximately 1 mm to 1.3 mm in diameter) is passed through the loop  100  of graft  90 . AM and PL graft bundles  95 AM,  95 PL are then manipulated into their approximate native anatomic locations at the mouth of femoral tunnel  80 . Next, femoral graft separator  235  is advanced over femoral guide wire  270  so as to engage graft bundles  95 AM,  95 PL. Femoral graft separator  235  is then used to manipulate and push graft  90  into femoral tunnel  80 . See  FIG. 40 . As graft  90  is pushed into femoral tunnel  80 , femoral graft separator  235  keeps the AM and PL bundles  95 AM,  95 PL aligned and in their desired anatomic positions. The passing sutures and graft tow sutures  105  are then used to pull graft  90  up into femoral tunnel  80 , i.e., by pulling on the passing sutures emerging from the distal end of femoral tunnel  80 . 
         [0135]    As a result of the foregoing, graft  90  will extend through tibial tunnel  70 , across joint space  60  and into femoral tunnel  80 , with the AM and PL bundles  95 AM,  95 PL aligned and in their desired anatomic positions. 
         [0136]    2. Second Approach for Graft Insertion 
         [0137]    In an alternative approach, and looking now at  FIG. 41 , the soft tissue graft  90  is prepared differently than previously described. Cadaveric evaluations and engineering tests have indicated this alternative method to be the preferred method of graft preparation when utilizing the new fixation device and technique. The folded-over length of graft  90  should measure 5 mm on each side of the fold (10 mm between the central whipstitched sections, when graft  90  is laid out end-to-end). Graft  90  is whipstitched with one color suture on one leg (i.e., one bundle  95 ) of the graft, and a second color suture on the other leg (i.e., the other bundle  95 ) of the graft. An additional suture, an anatomic guide wire passing suture  275 , is passed through the loop  100  of graft  90 , or pushed through the midsubstance of the graft via blunt dissection. 
         [0138]    In this form of the invention, and looking now at  FIG. 42 , graft  90  is towed into the tibial tunnel and then into the femoral tunnel, preferably by first positioning passing sutures from the anteromedial side of tibia  10 , up through tibial tunnel  70 , across joint space  60 , through femoral tunnel  80  and out the skin opposite the distal end of femoral tunnel  80  in the manner previously described, attaching the graft tow sutures  105  to the passing sutures, and then pulling on the passing sutures emerging from the distal end of femoral tunnel  80  to draw graft  90  up into tibial tunnel  70  and across joint space  60  until the graft just enters the joint space. See  FIG. 42 . Again, tibial graft separator  230  is inserted into tibial tunnel  70  along with graft  90 , separating the AM and PL bundles  95 AM,  95 PL from one another as they extend through tibial tunnel  70 . The anatomic guide wire passing suture  275  is kept easily accessible near the lateral side of the graft. The AM bundle  95 AM should be “on top of” tibial graft separator  230  and the PL bundle  95 PL should be “on the underside of” tibial graft separator  230 . 
         [0139]    The passing sutures and/or graft tow sutures  105  are then further pulled so as to advance graft  90  to the mouth of femoral tunnel  80 . See  FIG. 43 . With the knee in 90° of flexion, as is the typical surgical position, AM bundle  95 AM is positioned near the posterior portion of femoral tunnel  80 . The PL bundle  95 PL is positioned near the anterior portion of femoral tunnel  80 . Guide wire passing suture  275  is then used to pull a femoral guide wire  280  through the loop  100  in graft  90  (i.e., between the AM bundle  95 AM and the PL bundle  95 PL), or through the midsubstance of both graft bundles  95 AM,  95 PL together, and then through femoral tunnel  80 . More particularly, and as seen in  FIGS. 43 ,  43 A and  44 , this is preferably done by advancing forceps (not shown) through medial portal skin incision  85 ; picking up guide wire passing suture  275  with the forceps; pulling guide wire passing suture  275  out medial portal skin incision  85 ; engaging a guide wire suture  285  (which is threaded through the eyelet  290  of femoral guide wire  280 ); drawing guide wire suture  285  back through medial portal skin incision  85 , across joint space  60 , and through femoral tunnel  80 ; and then using guide wire suture  285  to pull femoral guide wire  280  through medial portal skin incision  85 , across joint space  60 , through the loop  100  in graft  90  (i.e., between the AM bundle  95 AM and the PL bundle  95 PL) and through femoral tunnel  80 . Note that guide wire suture  285  and femoral guide wire  280  are positioned such that they are in front of (i.e., anterior to) the AM bundle  95 AM to aid in the anatomic arrangement of the graft bundles. Note also that as the graft  90  is pulled into position, tibial graft separator  230  keeps the graft bundles  95 AM,  95 PL aligned in their respective AM and PL positions. 
         [0140]    As seen in  FIG. 43A , femoral guide wire  280  is rounded at its distal tip to prevent damage to the graft bundles  95 AM,  95 PL, but generally tapered to allow ease of passage through the graft bundles and the femoral tunnel. Femoral guide wire  280  is preferably flat on both sides (i.e., it has a generally rectangular cross-section with rounded sides) for later use during the insertion of the femoral fixation device and, if desired, the tibial fixation device (see below). Eyelet  290  is on the leading tip of femoral guide wire  280  to allow it to accept guide wire suture  285 , which is used to pull femoral guide wire  280  into femoral tunnel  80 . 
         [0141]    Graft  90  is then pulled slightly into the mouth of femoral tunnel  80  (i.e., by pulling distally on the passing sutures and/or graft tow sutures  105 ) and then retracted slightly to create a slight amount of slack in the graft. At this point, a cannulated femoral graft inserter  295  (see  FIGS. 45-47 ) is used to assist insertion of graft  90  into femoral tunnel  80 . Cannulated femoral graft inserter  295  comprises a body  297  and two legs, i.e., a lower leg  300  and an upper leg  305 . 
         [0142]    More particularly, femoral graft inserter  295  is used to keep graft bundles  95 AM,  95 PL separated while graft  90  is pulled into femoral tunnel  80 . Femoral graft inserter  295  is first introduced through the medial portal skin incision  85 , being careful to avoid catching soft tissue. Femoral graft inserter  295  is passed over femoral guide wire  280  to guide it up to the mouth of femoral tunnel  80 . The lower leg  300  of femoral graft inserter  295  is hooked around the PL graft bundle  95 PL. The legs  300 ,  305  of femoral graft inserter  295  are inserted slightly into the notches  185  already formed in femur  25 . Graft  90  is then pulled into femoral tunnel  80 . Note that the AM and PL bundles  95 AM,  95 PL are positioned by femoral graft inserter  295  into their respective AM and PL positions as graft  90  is pulled into femoral tunnel  80 , whereby to minor the natural anatomic positions of the AM and PL bundles of the native ACL. 
       Graft Fixation 
       [0143]    Graft  90  is then ready to be fixated into place with novel femoral and tibial fixation devices, i.e., a femoral fixation device  310  ( FIG. 47A ) and a tibial fixation device  315  ( FIG. 64 ). 
         [0144]    1. Femoral Fixation 
         [0145]    Looking now at  FIGS. 47A ,  48 - 59 A, femoral fixation device  310  comprises two components. The first component ( FIG. 48 ) consists of a femoral fixation screw  320  with a necked down region  325  at its distal tip and a reduced-diameter proximal head (or drive end)  330 . Femoral fixation screw  320  provides graft fixation as it is screwed into femoral tunnel  80 . Femoral fixation screw  320  tapers or curves to a narrow distal end to facilitate starting and insertion into the femoral tunnel. Also, femoral fixation screw  320  is cannulated to allow the use of femoral guide wire  280  (see above) to guide the femoral fixation screw straight into the femoral tunnel. A hex socket, hexalobe socket, square socket or other shaped socket  335  resides at the proximal end of femoral fixation screw  320  for engagement by an appropriate insertion (tightening) tool (i.e., a driver). 
         [0146]    The second component of femoral fixation device  310  is a femoral graft spacer  340  ( FIG. 49 ). Femoral graft spacer  340  has a distal end  342  having an opening  343  and a proximal end  345  having an opening  347 . Guide ribs  348  extend between distal end  342  and proximal end  347 . Proximal end  345  may be formed flat as shown in  FIG. 49  or, in the preferred embodiment, and as shown in  FIG. 50 , the proximal end  345  may be configured at an angle so as to form an elliptical face to more closely match the femoral bone surface at the joint side mouth of femoral tunnel  80 . Guide ribs  348  may have multiple barbs  350  as shown in  FIG. 49 , or a stepped feature  355  as shown in  FIG. 50 , to grip onto the side wall of femoral notches  185  and improve holding strength. Femoral graft spacer  340  has an internal cavity  360  sized to receive femoral fixation screw  320 . 
         [0147]    The purpose of femoral graft spacer  340  is to spread and separate the AM and PL bundles  95 AM,  95 PL as femoral fixation screw  320  is tightened into place in femoral tunnel  80 . Furthermore, femoral graft spacer  340  helps direct femoral fixation device  310  straight into femoral tunnel  80  by virtue of guide ribs  348  which track in the previously-created femoral notches  185 . Femoral fixation screw  320  and femoral graft spacer  340  are assembled together (see below) so that the two components can rotate independently of one another, thus allowing femoral graft spacer  340  to track in femoral notches  185  and maintain alignment of the graft bundles  95 AM,  95 PL while femoral fixation screw  320  is tightened so as to secure the graft ligament on the femoral tunnel. The angled proximal end  345  of femoral graft spacer  340  aligns to the bony surface of the femur at the joint side mouth of the femoral tunnel such that the bony defect in the femur is filled and the graft is supported around the elliptical mouth of the femoral tunnel. The angled proximal end  345  of femoral graft spacer  340  may be formed or manufactured in a variety of angles or shapes to best match the anatomy of the femur. Note that the angled proximal end  345  of femoral graft spacer  340  corresponds to the angle β and closely approximates the contour of the mouth of femoral tunnel  80 . 
         [0148]    Femoral fixation screw  320  and femoral graft spacer  340  are assembled together by capturing the femoral fixation screw within cavity  360  of femoral graft spacer  340 . This may be done by deforming femoral graft spacer  340  and snapping it over femoral fixation screw  320 . More particularly, to assemble the two components together, the femoral graft spacer  340  is aligned along the side of the femoral fixation screw  320  as shown in  FIG. 51 . The proximal head  330  of the femoral fixation screw  320  is then inserted into the opening  347  of the proximal end  345  of femoral graft spacer  340  as shown in  FIG. 52 . The distal tip of the femoral graft spacer  340  is then snapped over the distal tip of the femoral fixation screw  320  so that distal tip  325  of femoral fixation screw  325  is received in opening  343  in the distal end  342  of femoral graft spacer  340 , whereby to complete assembly of the two components. See  FIG. 53 . Note that when femoral fixation screw  320  and femoral graft spacer  340  are assembled together in this manner, femoral fixation screw  320  is free to rotate relative to femoral graft spacer  340 . 
         [0149]    The cross-sectional view in  FIG. 54  illustrates femoral graft spacer  340  assembled onto femoral fixation screw  320 . There is an angled surface  370  on the inside of femoral graft spacer  340  that allows femoral fixation screw  320  to be partially inserted into the femoral graft spacer prior to snapping the components into place. The femoral fixation screw is then supported on both ends of the femoral graft spacer (i.e., by engagement of the distal end  325  of femoral fixation screw  320  in opening  343  of femoral graft spacer  340 , and by engagement of the proximal end  330  of femoral fixation screw  320  in opening  347  of femoral graft spacer  340 ), and can rotate freely relative to the femoral graft spacer. 
         [0150]    Femoral graft spacer  340  functions as a means to align and separate the graft bundles  95 AM,  95 PL in femoral tunnel  80  and to fill the bony defect. Femoral graft spacer  340  can be positioned to spread the graft bundles  95 AM,  95 PL into their correct anatomic positions, regardless of the rotational position of femoral fixation screw  320 . Also, femoral graft spacer  340  may function as a “strain relief”, allowing the tension in graft  90  to be spread over the entire length of femoral fixation device  310 . 
         [0151]    Femoral fixation screw  320  and femoral graft spacer  340  may be made from metal, plastic (e.g., PEEK) and/or a bioabsorbable material. 
         [0152]    The end view shown in  FIG. 55  illustrates the contoured outer wall  375  of femoral graft spacer  340  for graft seating. The contoured outer wall  375  cooperates with guide ribs  348  to define graft recesses to engage with, and provide alignment of, the graft bundles  95 AM,  95 PL. Note that femoral fixation screw  320  extends radially outboard of contoured outer wall  375  of femoral graft spacer  340 . The shape of contoured outer wall  375  may be a variety of shapes to allow space for the graft strands. Guide ribs  348  that span the length of femoral graft spacer  340  are fit into the notches  185  previously formed in femoral tunnel  80 . In addition to guiding femoral fixation device  310  along femoral tunnel  80 , guide ribs  348  separate the graft bundles  95 AM,  95 PL and organize them onto one side or the other of femoral fixation device  310 . 
         [0153]    Femoral graft spacer  340  has smooth radii around critical corners to ensure strain-relieved fixation of the graft bundles. As femoral fixation device  310  is advanced along femoral tunnel  80 , guide ribs  348  glide into notches  185  of femoral tunnel  80  and center femoral graft spacer  340  onto the elliptical entrance of femoral tunnel  80 , thus separating the graft bundles  95 AM,  95 PL into their anatomically correct AM and PL locations. See  FIG. 56 . 
         [0154]    Proximal end  345  of femoral graft spacer  340  is angled (approximately equal to β) to create the mating elliptical, oval shape needed to fill the elliptical, oval-shaped joint-side entrance of femoral tunnel  80 . The angled shape of the proximal end of the femoral graft spacer fills the femoral tunnel entrance and urges the graft up against the tunnel entrance so as to mimic the wider anatomic footprint of the natural femoral insertion. The side view of the femoral fixation device is shown in  FIG. 57 , illustrating the angle β. 
         [0155]    Looking now at  FIG. 58 , which is a top view, femoral graft spacer  340  includes a tapered lead-in surface  380  that helps start the femoral graft spacer into femoral tunnel  80  and tunnel notches  185 . 
         [0156]    The lead tip  385  of femoral graft spacer  340  has a slot  390  that can be engaged with femoral guide wire  280 . See  FIGS. 59A and 59B . 
         [0157]    Femoral guide wire  280  is used to guide the femoral fixation device  310  to the femoral tunnel and to rotate the femoral fixation device  310  as needed so that the femoral fixation device is properly oriented with respect to the graft bundles  95 AM,  95 PL and with respect to the notches  185  in the femoral tunnel  80 . A guide wire dial  395  ( FIG. 60A ) slips over the distal end of femoral guide wire  280 , with a slot  400  on guide wire dial  395  engaging with flats  402  on femoral guide wire  280 , and is rotated so as to properly orient femoral fixation device  310  with respect to graft bundles  95 AM,  95 PL and femoral notches  185 . See  FIG. 60B . 
         [0158]    The AM and PL bundles  95 AM,  95 PL separate from each other on opposite sides of femoral graft spacer  340  as femoral fixation device  310  begins to engage with the femoral tunnel  80  ( FIG. 61 ). The AM and PL bundles  95 AM,  95 PL may be further manipulated, or spread out, with one bundle on each side of femoral fixation device  310 . The graft bundles  95 AM,  95 PL then align with, and fit in between, the recesses between the bone tunnel  80  and the femoral fixation device  310 . See  FIG. 61  showing the femoral fixation device  310  with its guide ribs  348  aligned with notches  185 . 
         [0159]    Femoral fixation device  310  is then fully advanced into femoral tunnel  80 , i.e., by using a driver  405  to turn femoral fixation screw  320 , which causes the threads of the femoral fixation screw to engage graft  90  and the side walls of femoral tunnel  80  and thereby advance femoral fixation device  310  up the femoral tunnel. As femoral fixation device  310  advances up femoral tunnel  80 , femoral fixation device  310  creates an interference fit between the femoral fixation device, the graft and the side walls of femoral tunnel  80 . Note that as femoral fixation device  310  advances within femoral tunnel  80 , tunnel notches  185  act as tracks for guide ribs  348  of femoral fixation device  310 , keeping the fixation centered in the femoral tunnel and maintaining separation of graft bundles  95 AM,  95 PL. When femoral fixation device  310  is fully seated in femoral tunnel  80 , the canted or angled surface  370  of the femoral graft spacer is approximately flush, or even with, the bone surface adjacent the joint-side mouth of femoral tunnel  80 . See  FIG. 62 . 
         [0160]    In the completed femoral ligament construct, the femoral fixation device  310  is seated approximately flush with the joint-side mouth of the femoral tunnel  80 . The graft is fixated between the femoral fixation screw threads and the femoral tunnel.  FIG. 63  shows a cross-section through the axis of the femoral fixation device that is perpendicular to the guide ribs  348  of the femoral graft spacer.  FIG. 63  illustrates how the graft is pressed between the femoral fixation screw and the side wall of the femoral tunnel and the graft fibers are interspersed between the threads of the femoral fixation screw. The graft exits the femoral tunnel in the area of the recesses of the femoral graft spacer, with the AM and PL bundles  95 AM,  95 PL separated into their correct anatomic positions. 
         [0161]    The femoral fixation device  310  provides significant advantages in femoral graft fixation: 
         [0162]    1. The final reconstructed graft construct more closely mimics the natural anatomic footprint of the femoral ligament insertion, resulting in a biomechanically superior reconstruction. The AM and PL bundles  95 AM,  95 PL are spread out over the elliptical anatomic footprint, with the femoral graft spacer  340  holding the graft to the rim of the femoral tunnel  80  about the periphery of the elliptical mouth of the femoral tunnel. 
         [0163]    2. The graft is secured at the joint-side mouth of the femoral tunnel (aperture fixation), eliminating the possible “windshield wiper” action of the graft over the bone surface. This windshield wiper action can lead to wear of the graft, wear of the bone surface, widening of the femoral tunnel, and potentially a failed reconstruction. 
         [0164]    3. In the event that the graft needs to be revised at a later date, the entire construct can be easily removed by removing the femoral fixation device  310  from the femur (e.g., by unscrewing the femoral fixation screw  320 ). The femoral graft spacer  340  and the femoral fixation screw  320  will remove as a single assembly, aiding in the revision process. 
         [0165]    4. Femoral graft spacer  340  also provides strain relief. More particularly, the strain on graft  90  is distributed over the entire length of femoral graft spacer  340 , rather than the abrupt strain resulting from the transition of a highly-compressed graft emerging from a standard interference screw/bone interface. 
         [0166]    5. And, guide ribs  348  of the femoral graft spacer  340  follow notches  185  in femoral tunnel  80 , ensuring that graft  90  remains centered in the femoral tunnel, evenly forcing graft  90  against the side wall of femoral tunnel  80 . 
         [0167]    2. Tibial Fixation 
         [0168]    Tibial fixation is effected using a tibial fixation device  315  which is generally similar to the aforementioned femoral fixation device  310 . Tibial fixation device  315  comprises a tibial graft spacer  410  and a tibial fixation screw  415 . See  FIG. 64 . 
         [0169]    Looking now at  FIG. 65 , tibial graft spacer  410  has a distal end  411  having an opening  412 , and a proximal end  413  having an opening  414 . Guide ribs  416  extend between distal end  411  and proximal end  413  of tibial graft spacer  410 . Tibial graft spacer  410  has an internal cavity  440  sized to receive tibial fixation screw  415 , as will hereinafter be discussed in greater detail. It should be appreciated that tibial graft spacer  410  is generally similar to femoral graft spacer  340  previously discussed, and shares a number of common features. These common features include an angled surface  420  whereby to provide an elliptical shape (but disposed on the distal end of the tibial graft spacer  410 , rather than on the proximal end as is the case with the femoral graft spacer  340 ), tapered lead-in surfaces  425  to aid insertion into the tibial tunnel, a contoured outer wall  430  for fixating the graft in the tibial tunnel, a slot  435  at the distal tip of distal end  411  of the tibial graft spacer  410  for, optionally, engaging with flats on a guide wire, and cannulation through the center of the tibial graft spacer (and its associated tibial fixation screw) for receiving a guide wire. See  FIG. 66 . If desired, guide ribs  416  can also include one or more barbs and/or one or more stepped features (analogous to barbs  350  and stepped feature  355  of femoral graft spacer  340 ) to grip onto the side wall of tibial notches  225  and improve holding strength. 
         [0170]    Tibial fixation screw  415  is shown in  FIG. 67 . Tibial fixation screw  415  has a necked down region  417  at its distal tip and a reduced-diameter proximal head (or drive end)  418 . Tibial fixation screw  415  tapers or curves to a narrow distal end to facilitate starting and insertion into the tibial tunnel. With the present invention, tibial fixation screw  415  may be the same design as femoral fixation screw  320 , but may be made in different lengths (i.e., 5 mm-10 mm longer) in order to utilize more of the tibial tunnel, which is typically longer than the femoral tunnel (in which case tibial graft spacer  410  has its length correspondingly adjusted). 
         [0171]    Tibial fixation device  315  is shown in cross-section in  FIG. 68 . The angle α 2  is shown at the angled surface  420  at the distal tip of tibial fixation device  315 . 
         [0172]      FIG. 69  illustrates tibial graft spacer  410  and the tibial fixation screw  415  in assembled form, whereby to form the complete tibial fixation device  315 . It will be appreciated that tibial graft spacer  410  and tibial fixation screw  415  are assembled together in substantially the same manner as femoral graft spacer  340  and femoral fixation screw  320  are assembled, i.e., by snapping tibial fixation screw  415  into cavity  440  formed in tibial graft spacer  410  (i.e., by deforming tibial graft spacer  410  and snapping it over tibial fixation screw  415 ). More particularly, to assemble the two components together, the tibial graft spacer  410  is preferably aligned along the side of tibial fixation screw  415 . The proximal head (or drive end)  418  of tibial fixation screw  415  is inserted into opening  414  of the proximal end  413  of tibial graft spacer  410 . The distal tip of tibial graft spacer  410  is then snapped over the distal tip of tibial fixation screw  415  so that the distal tip  417  of tibial fixation screw  415  is received in opening  412  in the distal end of tibial graft spacer  410 , whereby to complete assembly of the two components. It will also be appreciated that when tibial graft spacer  410  and tibial fixation screw  415  are assembled together in the foregoing manner, tibial fixation screw  415  will be free to rotate relative to tibial graft spacer  410 . 
         [0173]    The angle α 2  at the distal tip of tibial fixation device  315  corresponds to the angle resulting from the tibial tunnel drilling technique discussed above. The angled surface  420  at angle α 2  creates a close anatomic alignment between the bone surface (i.e., tibial plateau  50 ) and tibial fixation device  315 , and also secures the graft bundles  95 AM,  95 PL in their proper anatomic positions. 
         [0174]    Similar to the femoral fixation device  310 , the tibial fixation device  315  preferably has the aforementioned contoured outer wall  430  which cooperates with guide ribs  416  to define graft recesses on the top and bottom sides of the tibial graft spacer to engage with, and provide alignment of, graft bundles  95 AM,  95 PL, whereby to urge graft bundles  95 AM,  95 PL into their anatomic positions. See  FIG. 70 , viewed from the distal tip of tibial fixation device  315 . The recesses shown are preferably crescent-shaped (i.e., the same shape as the recesses of femoral graft spacer  340 ), although the recesses could have some other shape if desired. 
         [0175]    Tibial graft spacer  410  is sized relative to tibial fixation screw  415 . In one preferred form of the present invention, the graft recesses of tibial graft spacer  410  are smaller in size than tibial fixation screw  415 . Guide ribs  416  of the tibial graft spacer  410  are larger than the screw diameter for alignment and graft bundle separation. 
         [0176]    Guide ribs  416  that span the length of tibial graft spacer  410  are fit into notches  225  previously formed in tibial tunnel  70 . In addition to guiding tibial fixation device  315  along tibial tunnel  70 , guide ribs  416  separate the graft bundles  95 AM,  95 PL and organize them onto one side or the other of tibial fixation device  315 . It should be appreciated that tibial graft spacer  410  can be positioned to spread the graft bundles  95 AM,  95 PL into their correct anatomic position, regardless of the rotational disposition of tibial fixation screw  415 . 
         [0177]    Tibial fixation screw  415  and tibial graft spacer  410  may be made from metal, plastic (e.g., PEEK) and/or a bioabsorbable material. 
         [0178]    In the final step of the ligament reconstruction, tibial fixation device  315  is advanced into tibial tunnel  70  using a driver  450 .  FIG. 71  shows driver  450 , tibial fixation device  315  and the notched tibial tunnel  70 . The graft is omitted from  FIGS. 71-73  in order to illustrate the alignment of the tibial fixation device  315  and the tibial tunnel  70 . Tibial fixation device  315  is preferably advanced into tibial tunnel  70  in the following manner. Tibial graft separator  230  is removed from tibial tunnel  70 . Tibial fixation device  315 , manipulated by driver  450 , is advanced between graft bundles  95 AM,  95 PL, brought to the anteromedial mouth of tibial tunnel  70 , has its guide ribs  416  aligned with tunnel notches  225 , and tibial fixation screw  415  is turned with driver  450 , causing tibial fixation device  315  to advance along tibial tunnel  70 , creating an interference fit between tibial fixation device  315 , graft bundles  95 AM,  95 PL and the side wall of tibial tunnel  70 . Note that as tibial fixation device  315  is advanced up tibial tunnel  70 , guide ribs  416  of tibial fixation device  315  orient and separate the graft bundles  95 AM,  95 PL into their anatomically correct AM and PL locations. If desired, tibial fixation device  315  can be set using driver  450  alone (as shown in  FIG. 71 ) or, if desired, tibial fixation device  315  and driver  450  can be tracked over a guide wire (which may be a guidewire such as guidewire  280  having flats  402 ) so that the guidewire can be used to rotate tibial fixation device  315  to a desired angular disposition (i.e., to line up with tibial notches  225  and separate graft bundles  95 AM,  95 PL). 
         [0179]    In the case of tibial fixation device  315 , the strength of the construct is enhanced by driving the fixation into the tibial tunnel until distal end  411  of tibial graft spacer  410  contacts the subchondral bone at the distal end of tibial notches  225  (which terminate proximal of tibial plateau  50 ). See  FIG. 72  which is a cross-sectional view through the axis of tibial fixation device  315 , in the central plane of guide ribs  416  of tibial graft spacer  410 . As noted above, during the preparation of the tibial tunnel, notcher  165  is preferably driven up to the subchondral bone but then stopped, leaving a shelf for the distal end of tibial fixation device  315  to rest against. Tension in graft  90  pulls tibial fixation device  315  against the subchondral bone shelf. The combination of strong aperture fixation and the resistance of tibial fixation device  315  against the subchondral shelf creates a very strong tibial ligament construct (i.e., a very strong fixation of graft  90  to tibia  10 ). As tibial fixation device  315  advances up tibial tunnel  70 , tibial fixation device  315  creates an interference fit between the tibial fixation device  315 , graft  90  and the side walls of tibial tunnel  70 , in the same manner as with the femoral fixation device. Furthermore, the fibers of graft  90  lodge between the screw threads of tibial fixation screw  415  in a manner similar to that of femoral fixation device  310 , contributing to the strong aperture fixation. 
         [0180]      FIG. 73  shows femoral fixation device  310  and tibial fixation device  315  secured in their respective positions within femoral tunnel  80  and tibial tunnel  70 , respectively. Both femoral fixation device  310  and tibial fixation device  315  lie approximately flush with the bone surfaces surrounding the mouths of their respective bone tunnels on the inside of the knee joint (i.e., with angled surface  370  of femoral graft spacer  340  disposed at the proximal end of femoral tunnel  80  proximate joint space  60 , and with angled surface  420  of tibial graft spacer  410  disposed at the distal end of tibial tunnel  70  proximate joint space  60 ). Guide ribs  348  of femoral graft spacer  340  lie within femoral notches  185 , and guide ribs  416  of tibial graft spacer  410  lie within tibial notches  225 , providing definitive passageways for the AM and PL bundles  95 AM,  95 PL. 
         [0181]    The finished construct, showing the AM and PL bundles  95 AM,  95 PL in position, is shown in  FIG. 74 . 
         [0182]    Tibial fixation device  315  provides significant advantages in tibial graft fixation: 
         [0183]    1. The final reconstructed graft construct more closely mimics the natural anatomic footprint of the tibial ligament insertion, resulting in a biomechanically superior reconstruction. The AM and PL bundles  95 AM,  95 PL are spread out over the elliptical anatomic footprint, with the tibial graft spacer  410  holding the graft to the rim of tibial tunnel  70  about the periphery of the elliptical mouth of the tibial tunnel. 
         [0184]    2. The graft is secured at the joint-side mouth of the tibial tunnel (aperture fixation), eliminating the possible “windshield wiper” action of the graft over the bone surface. This windshield wiper action can lead to wear of the graft, wear of the bone surface, widening of the tibial tunnel, and potentially a failed reconstruction. 
         [0185]    3. The bony defect from the drilling process is filled by tibial fixation device  315 . 
         [0186]    4. Tibial graft spacer  410  ensures that tibial fixation device  315  goes in straight and follows notches  225  in tibial tunnel  70 , eliminates screw divergence and enhances fixation strength by distributing forces over a larger area. 
         [0187]    5. In the event that the graft needs to be revised at a later date, the entire construct can be easily removed by loosening tibial fixation device  315  from the tibia (e.g., by unscrewing tibial fixation screw  415  from tibial tunnel  70 ). Tibial graft spacer  410  and tibial fixation screw  415  will remove as a single assembly, aiding in the revision process. 
         [0188]    6. Tibial graft spacer  410  provides strain relief to distribute the stress over the face of the tibial fixation device  310 , whereby to create a smooth and gradual transition from the compression of tibial fixation screw  415 . 
         [0189]    The foregoing discussion describes the preferred embodiments of femoral fixation device  310  and tibial fixation device  315  and and their preferred method of use. However, if desired, alternative constructions may be utilized with the present invention. 
         [0190]    By way of example but not limitation, femoral fixation device  310  and/or tibial fixation device  315  may be modified to permit the components to be manufactured using other methods such as injection molding.  FIGS. 75A and 75B  illustrate design modifications to tibial fixation device  315  that may permit injection molding. The proximal opening  414  of tibial graft spacer  410  is formed as a tapered slot or hole  455 , such that the opening does not form an undercut surface for the purpose of molding. The taper still permits assembly of tibial fixation screw  415  inside of tibial graft spacer  410 , as described above. Tibial fixation screw  415  may have a deeper, tapered drive recess  460  (formed by an alternate polygon, such as the five-sided polygon shown) formed in reduced diameter proximal head (or drive end)  415  of tibial fixation screw  415 . This would provide more surface area to distribute drive forces, which can be an important consideration where the component is molded from plastic. 
         [0191]    Similar changes may be made to the femoral fixation device  310 . 
         [0192]    Additionally, small protrusions  465  ( FIG. 76 ) may extend from the distal end of the femoral graft spacer  340 . These protrusions capture a graft between the end of femoral fixation device  310  and the far end of the femoral tunnel, as may be commonly used in tenodesis procedures of the biceps tendon, or other soft tissue connections. 
         [0193]    In another version of the present invention, the guide ribs  348  of the femoral graft spacer  340  may not be symmetric, but positioned asymmetrically about the femoral fixation screw. See  FIG. 77 . This can be useful when the graft is closely compressed on the narrow side, and more spread out on the broader side. It may also be useful when a bone block graft is to be positioned on one side. 
         [0194]    Similar changes may be made to the tibial fixation device. 
         [0195]    In another version of the present invention, and looking now at  FIG. 78 , femoral graft spacer  340  may be formed with a single guide rib  348  positioned symmetrically or asymmetrically about femoral fixation screw  320 . This can be useful when the entirety of the graft is intended to be secured in one area. This may also be useful when a bone block graft is to be positioned on one side. 
         [0196]    Similar changes may be made to the tibial fixation device. 
       Modifications of the Preferred Embodiments 
       [0197]    It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.