Abstract:
A soft tissue fixation system, most typically applicable to orthopedic joint repairs, such as anterior cruciate ligament (ACL) knee repair procedures, comprises an implant which is placeable in a tunnel disposed in a portion of bone, wherein the tunnel is defined by walls comprised of bone. A first member is deployable outwardly to engage the tunnel walls for anchoring the implant in place in the tunnel, and a second member is deployable outwardly to engage tissue material to be fixed within the tunnel. The second member also functions to move the tissue material outwardly into contact with the tunnel walls to promote tendon-bone fixation. Extra graft length is eliminated by compression of the tendon against the bone at the aperture of the femoral tunnel, which more closely replicates the native ACL and increases graft stiffness. The inventive device provides high fixation of tendon to bone and active tendon-bone compression. Graft strength has been found to be greater than 1,000 N (Newtons), which is desirable for ACL reconstruction systems.

Description:
[0001]    This application claims the benefit under 35 U.S.C. 119(e) of the filing date of Provisional U.S. application Ser. No. 60/854,178, entitled Methods and Systems for Material Fixation, filed on Oct. 24, 2006, which application is expressly incorporated herein by reference. 
         [0002]    This application is also related to co-pending U.S. application Ser. No. 11/281,566 entitled Devices, Systems, and Methods for Material Fixation, filed on Nov. 18, 2005 and published as U.S. Patent Application Publication No. US 2006/0155287 on Jul. 13, 2006, and to co-pending U.S. application Ser. No. 11/725,981, entitled Devices, Systems, and Methods for Material Fixation, filed on Mar. 20, 2007. Both of these prior pending applications are commonly owned and herein expressly incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates generally to devices, systems and methods for material fixation. More specifically, the present invention relates to a technique that can be used to firmly hold a soft tissue or graft against bone tissue within a bone tunnel. 
         [0004]    One of the most common needs in orthopedic surgery is the fixation of tendon to bone. The fixation of diseased tendons into a modified position is called tenodesis and is commonly required in patients with injury to the long head of the biceps tendon in the shoulder. In addition, tendons which are torn from their insertion site into bone also frequently require repair. This includes distal biceps tendon tears, rotator cuff tears, and torn flexor tendons in the hand. Tendons are also frequently used in the reconstruction of unstable joints. Common examples include anterior cruciate ligament and collateral ligament reconstructions of the knee, medial and lateral elbow collateral ligament reconstructions, ankle collateral ligament reconstruction, finger and hand collateral ligament reconstructions and the like. 
         [0005]    Traditional techniques that are used to fix tendon to bone suffer from a number of limitations as a result of the methodology used, including the use of a “keyhole” tenodesis, pull-out sutures, bone tunnels, and interference screw fixation. The “keyhole” tenodesis requires the creation of a bone tunnel in the shape of a keyhole, which allows a knotted tendon to be inserted into the upper portion, and subsequently wedged into the lower narrower portion of the tunnel where inherent traction on the tendon holds it in place. This technique is challenging as it is often difficult to sculpt the keyhole site and insert the tendon into the tunnel. In addition, if the tendon knot unravels in the postoperative period, the tendon will slide out of the keyhole, losing fixation. 
         [0006]    Another traditional form of tendon fixation is the use of the “pull-out stitch.” With this technique, sutures attached to the tendon end are passed through bone tunnels and tied over a post or button on the opposite side of the joint. This technique has lost favor in recent years due to a host of associated complications, which include wound problems, weak fixation strength, and potential injury to adjacent structures. 
         [0007]    The most common method of fixation of tendon to bone is the use of bone tunnels with either suture fixation, or interference screw fixation. The creation of bone tunnels is relatively complicated, often requiring an extensive exposure to identify the margins of the tunnels. Drill holes placed at right angles are connected using small curettes. This tedious process is time-consuming and fraught with complications, which include poor tunnel placement and fracture of the overlying bone bridge. Graft isometry, which is easy to determine with single point fixation, is difficult to achieve because the tendon exits the bone from two points. After creation of tunnels, sutures must be passed through the tunnels to facilitate the passage of the tendon graft. Tunnels should be small enough to allow good tendon-bone contact, yet large enough to allow for graft passage without compromising the tendon. This portion of the procedure is often time-consuming and frustrating to a surgeon. Finally, the procedure can be compromised if the bone bridge above the tunnel breaks, resulting in loss of fixation. The technique restricts fixation to the strength of the sutures, and does not provide any direct tendon to bone compression. 
         [0008]    More recent advances in the field of tendon fixation involve the use of an internally deployed toggle button, for example, the EndoButton ®, and the use of interference screws to provide fixation. The EndoButton, by Smith &amp; Nephew, allows the fixation of tendon into a bone tunnel by creating an internally deployed post against a bony wall. While this technique eliminates the need for secondary incisions to place the post, the fixation strength is limited to suture strength alone. This technique does not provide direct tendon to bone compression; as such this technique may slow healing and lead to graft tunnel widening due to the “bungee effect” and “windshield wiper effect”. As a result, this technique has limited clinical applications and is used primarily for salvage when bone tunnels break or backup fixation is important. 
         [0009]    The use of the interference screw is the most notable advance in the fixation of tendon to bone. The screw is inserted adjacent to a tendon in a bone tunnel, providing axial compression between the screw threads and the bony wall. Advantages include acceptable pull-out strength and relative ease of use. Aperture fixation, the ability to fix the tendon to bone at its entrance site, is a valuable adjunct to this technique as it minimizes graft motion and subsequent tunnel widening. Some disadvantages related to soft tissue interference screws are that they can be difficult to use, and can also cut or compromise the tendon during implantation. 
         [0010]    The newest generation interference screw allows the ability to provide tendon to bone fixation with limited exposure. For example, the Bio-Tenodesis Screw™ (Arthrex, Inc.) allows the tensioning and insertion of tendon into bone, followed by insertion of an adjacent soft tissue interference screw. While this screw system provides advantages in the insertion of tendon into bone in cases when a pull through stitch is not available, it is still limited by the potential for tendon rotation or disruption as the screw compresses the tendon. The surgical technique is also complicated, typically requiring two or more hands for insertion, making it difficult to use the system without assistance during arthroscopic or open procedures. Finally, the use of the screw requires preparation of the tendon end, which can be difficult, time consuming, and can also require conversion of an arthroscopic procedure to open. 
         [0011]    Referring particularly to the field of repairing an anterior cruciate ligament (ACL) injury, current repair techniques utilizing soft tissue for the replacement graft are either difficult to perform or they result in less than favorable outcomes due to their relatively low tendon-to-bone fixation. Existing ACL reconstruction techniques that have acceptable outcomes (high tendon-to-bone fixation strength) require extra operating room time and surgeon effort due to the requirements of multiple drill holes, external guides and fixtures for the drill holes, and multiple assistants. Another difficulty with current techniques is that they do not well replicate the native ACL in its anatomy or physiology. Two important factors in replicating the native ACL are aperture compression (compressing the tendon against the bone at the opening of the drill hole into the joint) and tendon length. Compression of the tendons at the aperture of the femoral tunnel will improve the healing process by increasing the intimate contact between the tendon and the bone. Studies show that the lack of intimate contact between the tendon and bone can result in less well organized fibrous tissue, resulting in lower pull-out strengths. The stiffness of the repair is also important to replicate the native ACL. Graft stiffness is decreased by the length of tendon between the fixation points. 
         [0012]    Currently, two different sources are utilized for the tissue that replaces the injured native ACL. When the new tissue comes from the patient&#39;s own body, the new graft is referred to as an autograft, and when cadaveric tissue is used, the new graft is referred to as an allograft. The most common autograft ACL reconstruction performed currently is the bone-patellar tendon-bone (BTB) graft. The BTB graft fixed with an interference screw is used more often because it more accurately replicates the native ACL, due to its aperture compression at the femoral tunnel aperture. However, BTB reconstructions result in an increased rate of anterior knee pain post-surgically for periods of up to 3 years after the reconstruction. Additionally, the harvest procedure for the BTB autograft is invasive and can be difficult to perform. Alternatively, the hamstring tendon autograft ACL reconstruction technique does not result in any significant post-surgical pain, and the harvest procedure is minimally invasive compared to the BTB graft harvest. The reason that the hamstring tendon autograft procedure is not used more frequently in ACL reconstructions is that the fixation of the hamstring tendons to the femur and tibia are not as strong as the fixation of the BTB autografts. 
         [0013]    Many prior art systems have addressed some of the problems associated with ACL reconstruction using hamstring tendons, but there is not one system that addresses them all. For example, the EndoButton system (Smith &amp; Nephew) is easy to use and does not need additional drill holes. However, it does require additional accessories and additional people to perform the procedure and does not replicate the native ACL due to a lack of tendon-to-bone compression at the aperture, as well as additional length of tendon between fixation points. The EndoButton system is an example of a cortical hamstring fixation device that yields a longer graft construct, resulting in a graft that is less stiff than the native ACL. Peer reviewed journal data show that existing soft tissue fixation systems with long graft lengths between fixation points have as much as a 56% reduction in graft stiffness when compared to the native ACL. 
         [0014]    The RigidFix® product by Mitek is a cross pin device that requires multiple drill holes, additional instruments, and assistance from other people in the operating room to complete the repair. Also, there is only passive compression of tendon to bone, not direct, active compression. 
         [0015]    The Stratis® ST product by Scandius attempts to more accurately replicate the native ACL by adding material to take up space in the femoral tunnel resulting in more intimate contact between the tendon and the bone. However, to insert the device into the femoral tunnel, the cross-sectional area must be less than the cross-sectional area of the hole. Thus, there is no real compression of tendon to bone. The Stratis ST product also requires additional drill holes, accessories, and people to properly perform the procedure. 
         [0016]    The EZLOC™ product by Arthrotek provides high strength and attempts to more accurately replicate the native ACL in the same fashion as the Stratis ST product, by taking up the space in the femoral tunnel. This does create more intimate contact between the tendon and bone, but does not offer real compression at the aperture. 
         [0017]    Interference screws such as the RCI 198  Screw, available from Smith &amp; Nephew, are easy to use and provide compression of tendon to bone at the femoral tunnel aperture. However, the pull-out strength and stiffness of the repair are significantly lower than the preceding systems. 
         [0018]    Thus, although there are many conventional techniques used for the fixation of tendon to bone, each having some advantages, the disadvantages of each such technique presents a need in the art for a simple and universal technique to fixate tendon to bone such that the device is easy to use, the process is simple to follow, and the result is a firm and secure tendon to bone fixation with minimal negative effect on the tendon. Further, such device should be easy to manufacture, universally applied to different tendon to bone sites, and require minimal effort to understand and use in practice. 
       SUMMARY OF THE INVENTION 
       [0019]    The present invention is a device that is easy to use, provides high fixation of tendon-bone and active tendon-bone compression, requires no additional accessories, uses only one drill hole, and can be implanted by one practitioner. The invention utilizes cancelous bone for fixation, and replicates the native ACL by compressing the tendons against the bone at the aperture of the femoral tunnel, effectively shortening the length of the graft as compared to cortical hamstring fixation devices. An important advantage of the invention is the improvement of the tendon-bone fixation of hamstring autografts as well as other soft-tissue ACL reconstruction techniques. Extra graft length is eliminated by compression of the tendon against the bone at the aperture of the femoral tunnel, which more closely replicates the native ACL and increases graft stiffness. The inventive device provides high fixation of tendon to bone and active tendon-bone compression. Graft strength has been found to be greater than 1,000 N (Newtons), which is desirable for ACL reconstruction systems. 
         [0020]    More particularly, there is provided in one aspect of the invention a material fixation system, which comprises an implant which is placeable in a tunnel disposed in a portion of bone, wherein the tunnel is defined by walls comprised of bone. A first member is deployable outwardly to engage the tunnel walls for anchoring the implant in place in the tunnel, and a second member is deployable outwardly to engage tissue material to be fixed within the tunnel. The second member also functions to move the tissue material outwardly into contact with the tunnel walls. A third member forming a part of the implant is movable to deploy the first member outwardly. A fourth member is provided actuating the third member to move in order to deploy the first member. 
         [0021]    Preferably, the fourth member comprises a portion which functions to deploy the second member outwardly. The implant comprises a body having a distal end and a proximal end, and the first member is disposed on the body. The first member comprises an arm which is pivotally attached to the body. The third member comprises a wedge which is movable generally axially to deploy the arm. 
         [0022]    In one presently preferred embodiment, the fourth member comprises a deployment screw having a distal end and a proximal end, wherein the deployment screw is adapted to extend axially through the body. The distal end of the deployment screw has a threaded portion which is engageable with a complementary threaded portion on the wedge, wherein rotation of the deployment screw causes relative movement of the deployment screw and the wedge. The wedge moves proximally to deploy the arm. 
         [0023]    The aforementioned second member comprises a compression pad. In the preferred embodiment, the fourth member portion comprises a head of the deployment screw, disposed on the proximal end thereof. 
         [0024]    In another aspect of the invention, there is provided an anchor for securing soft tissue into a portion of bone, which comprises a body portion having a distal end and a proximal end. At least one outwardly deployable anchoring member is disposed on the body. A wedge member is movable for deploying the at least one outwardly deployable anchoring member. The anchor further comprises a generally axially movable deploying member for moving the wedge member. The deploying member engages the wedge member to move the wedge member, and is disposed proximally of the wedge member. 
         [0025]    Preferably, the aforementioned wedge member is disposed distally of the outwardly deployable anchoring member, and moves proximally in order to deploy the outwardly deployable anchoring member outwardly. The anchor further comprises an outwardly deployable compression member for engaging a portion of soft tissue and pushing the soft tissue outwardly into contact with adjacent bone. The outwardly deployable compression member is proximal to the outwardly deployable anchoring member. A portion of the generally axially movable deploying member is adapted to deploy the compression member outwardly. Again, referencing currently preferred embodiments, the at least one outwardly deployable anchoring member comprises an arm pivotally attached to the body, and the generally axially deploying member comprises a threaded deployment screw. 
         [0026]    In yet another aspect of the invention, there is provided an implant system for use in making an orthopedic repair of a joint, which comprises a first implant adapted for receiving a tissue graft thereon and then being disposed in a first bone tunnel location, wherein ends of the tissue graft extend through a bone tunnel and out of a proximal end of the tunnel. The first implant comprises a body portion having a distal end and a proximal end, and a first member disposed on the body portion which is deployable outwardly to engage adjacent bone for anchoring the implant in place in the tunnel. The first implant further comprises a second member disposed on the body portion which is deployable outwardly to engage tissue material to be fixed within the tunnel, and to move the tissue material outwardly into contact with the tunnel walls. The implant system further comprises a second implant adapted for disposition in a second bone tunnel location, proximal to the first bone tunnel location. The second implant is adapted to secure the ends of the tissue graft which extend from the first implant against adjacent bone. The first implant further comprises a third member which is movable to deploy the first member outwardly. A fourth member is provided for actuating the third member to move in order to deploy the first member. 
         [0027]    In still another aspect of the invention, there is disclosed a method of making an orthopedic repair by fixing a soft tissue graft to bone, which comprises steps of placing a soft tissue graft on an implant, and disposing the implant within a bone tunnel at a desired location, such that a plurality of ends of the soft tissue graft extend from the implant in a proximal direction through the bone tunnel. Additional steps include deploying a first member on a body of the implant outwardly so that portions of the first member engage adjacent bone to secure the implant in place at the desired location, and deploying a second member on the body of the implant outwardly, so that portions of the second member engage portions of the plurality of ends of the soft tissue graft and push the soft tissue graft ends into contact with adjacent bone. 
         [0028]    The invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is an isometric view of an embodiment of a device constructed in accordance with the principles of the present invention; 
           [0030]      FIG. 2A  is a top view of the device of  FIG. 1  in an undeployed configuration; 
           [0031]      FIG. 2B  is a side view of the device of  FIG. 2A ; 
           [0032]      FIG. 3A  is a top view of the device of  FIG. 1 , wherein the deployment screw is starting to deploy the compression pads; 
           [0033]      FIG. 3B  is a side view of the device of  FIG. 3A ; 
           [0034]      FIG. 4A  is a top view of the device of  FIG. 1 , wherein the compression pads have been fully deployed; 
           [0035]      FIG. 4B  is a side view of the device of  FIG. 4A ; 
           [0036]      FIG. 5  is a top view of the device of  FIG. 1 , wherein the wedge is starting to deploy the arms; 
           [0037]      FIG. 6  is a top view of the device of  FIG. 1 , wherein the wedge is halfway engaged; 
           [0038]      FIG. 7A  is a top view of the device of  FIG. 1 , wherein the implant has been fully deployed; 
           [0039]      FIG. 7B  is a side view of the device of  FIG. 7A ; 
           [0040]      FIG. 8  is a view illustrating the implant of  FIG. 1 , as it is deployed in the femoral tunnel of a patient; 
           [0041]      FIG. 9A  is a view illustrating tendon compression as effected by the embodiment of  FIGS. 1-7 ; 
           [0042]      FIG. 9B  is a detail view of a portion of  FIG. 9A  denoted by a circle labeled as “ 9 B”; 
           [0043]      FIG. 10  is a perspective view, in isolation, of a deployment screw for use in the embodiment of  FIGS. 1-7 ; 
           [0044]      FIG. 11A  is a perspective view of a compression pad for use in the embodiment of  FIGS. 1-7 ; 
           [0045]      FIG. 11B  is a perspective view of a second compression pad; 
           [0046]      FIG. 12  is a perspective view of the body of the implant of  FIGS. 1-7 ; 
           [0047]      FIGS. 13A and 13B  are perspective views of arms for use in the embodiment of  FIGS. 1-7 ; 
           [0048]      FIGS. 14A and 14B  are perspective views of the wedge for use in the embodiment of  FIGS. 1-7 ; 
           [0049]      FIGS. 15A and 15B  are perspective views of modified embodiments of the implant of  FIGS. 1-7  with arms flipped to engage with the cortical surface during a soft tissue repair procedure; 
           [0050]      FIGS. 16A and 16B  are perspective views of yet another embodiment of the implant of the invention, wherein the body is used as the wedge; 
           [0051]      FIG. 17  is a table summarizing the performance of an implant constructed in accordance with the principles of the present invention, as shown in  FIGS. 1-7 ; 
           [0052]      FIG. 18  is an isometric view of a further modified embodiment of the invention; 
           [0053]      FIG. 19  is an exploded view of the embodiment of  FIG. 18 ; 
           [0054]      FIG. 20  is a plan view of the embodiment of  FIG. 18 , in an undeployed configuration; 
           [0055]      FIG. 21  is a side view of the embodiment of  FIG. 20 ; 
           [0056]      FIG. 22  is a plan view of the embodiment of  FIG. 20 , wherein the deployment screw is starting to deploy the compression pads; 
           [0057]      FIG. 23  is a side view of the embodiment of  FIG. 22 ; 
           [0058]      FIG. 24  is a view illustrating the implant of  FIGS. 18-23  deployed in a femoral tunnel; 
           [0059]      FIG. 25  is a detailed view similar to  FIG. 24 , showing tendon compression performed by the deployed inventive device; 
           [0060]      FIG. 26  is a perspective view of the deployment screw; 
           [0061]      FIG. 27  is a view showing the body of the implant; 
           [0062]      FIG. 28  is a view similar to  FIG. 27 , but showing the implant from a different orientation; 
           [0063]      FIG. 29  is an isometric view of an arm in accordance with the invention; 
           [0064]      FIG. 30  is an isometric view from a different orientation than  FIG. 29 , showing the arm; 
           [0065]      FIG. 31  is a view of the wedge of the invention; 
           [0066]      FIG. 32  is a data table; 
           [0067]      FIG. 33  is an isometric view of another embodiment of the invention, comprising an undeployed cortical fixation implant; 
           [0068]      FIG. 34  is an isometric view of the cortical fixation implant of  FIG. 33 , from a different orientation; 
           [0069]      FIGS. 35 and 36  are top and side views, respectively, of the cortical implant of  FIGS. 33 and 34 ; 
           [0070]      FIGS. 37 and 38  are top and side views, respectively, of the cortical implant of  FIGS. 33 and 34 , wherein the implant is beginning to be deployed; 
           [0071]      FIGS. 39 and 40  are top and side views, respectively, of the cortical implant of  FIGS. 37 and 38 , wherein the implant is in a deployed state; 
           [0072]      FIGS. 41 and 42  show a deployment sequence for the cortical fixation implant; 
           [0073]      FIG. 43  is an isometric view of the body of the implant of  FIG. 33 , showing integrated compression pads; 
           [0074]      FIG. 44  is a cross-sectional view of the body of  FIG. 43 , taken along the lines  44 - 44  of  FIG. 45 ; 
           [0075]      FIG. 45  is a side view of the implant of  FIG. 43 ; 
           [0076]      FIG. 46  is a perspective view of the wedge of the invention; 
           [0077]      FIGS. 47 and 48  are views of the arm of the invention; 
           [0078]      FIG. 49  is a perspective view of the compression wedge of the invention; 
           [0079]      FIG. 50  is a perspective view of the deployment screw of yet another embodiment of the inventive implant; and 
           [0080]      FIGS. 51-52  are isometric views of an additional embodiment of a cortical implant of the invention, wherein  FIG. 51  shows the device in its undeployed configuration and  FIG. 52  shows the device in its deployed configuration; 
           [0081]      FIGS. 53-54  are isometric views of still another embodiment of a cortical implant of the invention, wherein  FIG. 53  shows the device in its undeployed configuration and  FIG. 54  shows the device in its deployed configuration; and 
           [0082]      FIG. 55  is a view of the femur and tibia of a patient&#39;s leg, showing a substantially completed ACL repair. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0083]    Referring now more particularly to the drawings, procedures and anchoring devices for repairing soft tissue are illustrated. In  FIG. 1 , one embodiment of an implant  10 , constructed in accordance with the principles of the present invention, is shown. The implant  10  comprises a deployment screw  12 , which protrudes through a pair of compression pads  14  and  16 . The implant  10  comprises a body  18 , through which the deployment screw  12  also protrudes. The deployment screw  12  , at its distal end, is threaded into a wedge  20 . 
         [0084]    The left compression pad  14  slides into the right compression pad  16 , and they attach to one another. Two pins  22  attach a pair of arms  24  to the body  18 . There is a track  26  on each side of the wedge  20 , best seen in  FIG. 14A . Each wedge track  26  attaches to a track post  28  ( FIG. 13B ) on a corresponding one of the arms  24 . The wedge tracks  26  function to prevent the wedge from rotating during deployment of the implant. 
         [0085]    The compression pads  14 ,  16  slide into a pair of body tracks  30  ( FIG. 12 ) in the body  18 , which allow the pads  14 ,  16  to expand when the deployment screw  12  is rotated clockwise, as shown in  FIGS. 2-4 . The body tracks  30  also prevent the pads  14 ,  16  from rotating. 
         [0086]    In  FIG. 10 , the deployment screw  12  is shown in detail. This screw  12  comprises a quad lead section  32 , with four separate thread starts. This means that, for every single turn on the screw, the linear distance it travels is four times what a single lead screw would be. This feature enables the user to turn the screw fewer times than would be required with a single start thread, approximating the same number of turns that the user would need during the implantation of an interference screw such as the above described Smith &amp; Nephew RCI screw. Often, during implantation, an interference screw requires a notch to be placed at the edge of the femoral tunnel aperture to allow the screw to start engaging into the bone. Advantageously, the need for this step is eliminated when deploying the implant of the present invention, resulting in a substantially easier implementation procedure. 
         [0087]    Accordingly, the present invention is easy to deploy as an interference screw, and requires fewer steps than in prior art approaches. The deployment screw  12  also provides a rigid backbone to support the implant. A screw head or compression pad deployer  34  deploys the compression pads  14 ,  16  as the screw  12  moves axially into the implant. Another feature of the screw  12  is a load transfer disk  36  that transfers some of the axial load from a junction between the screw head  34  and the body  18  to a junction between the load transfer disk  36  and the body  18 . This load transferring feature allows for thinner side walls or struts  38  on the body  18  due to a decreased load on struts  38  ( FIG. 12 ), which, in turn, allows a larger tendon to fit between the deployment screw  12  and the body  18 . 
         [0088]    With reference now particularly to  FIGS. 11A and 11B , the compression pads  14  and  16  are shown in greater detail. The left and right compression pads  14 ,  16 , respectively, compress the tendons against the femoral tunnel wall to promote tendon-to-bone healing at the aperture of the tunnel. Unlike current approaches for more intimate tendon-to-bone contact that only reduce the space between the tendon and the tunnel wall, the present invention actively compresses the tendons against the bone tunnel. Compression pad tracks  40  engage the body tracks  30  and interlock them to the body  18 . This joint also provides torsional resistance while moving the implant into place, and during initial deployment until the arms  24  start to engage with the bone. There are engagement slots  42  in each compression pad  14 ,  16 , as shown, that engage with a deployment device that keep the implant  10  from rotating until the arms  24  engage the bone. The two compression pads  14 ,  16  snap together using compression pad snaps  44  to prevent premature deployment of the pads. 
         [0089]    Now referring to  FIG. 12 , the body  18  functions to trap the tendons on either side of the deployment screw  12 . The compression pads  14 ,  16  engage the body tracks  30  and provide torsional strength to the body while inserting the implant into the femoral tunnel, thus allowing the compression pads  14 ,  16  to expand parallel to one another. The struts  38  also provide structural support for the deployment screw  12 , wedge  20 , and arms  24  to deploy against. 
         [0090]    The arms  24  have a few key design features, as best shown in  FIGS. 13A and 13B . Fins  46  on the top of each arm provide torsional strength for the wedge-to-arm junction. The fins  46  also allow easier insertion into the femoral tunnel when inserting into a femoral tunnel that is drilled off-axis from the tibial tunnel. The portion of the arm  24  that engages with the bone has a tapered edge  48  which allows for ease of bone displacement during deployment. A support rib  50  disposed along the length of the arm  24  is also tapered for ease of bone displacement, and provides structural support during axial loading. Torsion pins  52  engage with a torsion hole  54  to provide additional torsional strength while the implant is being implanted into the femoral tunnel. 
         [0091]      FIGS. 14A and 14B  show, in greater detail, particular constructional features of the wedge  20 . The wedge  20  is threaded with a female quad lead thread  56  that matches the male quad lead thread  32  of the deployment screw  12 . The track posts  28  engage with the wedge tracks  26  to provide torsional strength through deployment. A tapered nose  58  on the wedge  20  allows easier off-axis insertion into the femoral tunnel. 
         [0092]    Referring now to  FIGS. 2-9 , a preferred method of using the disclosed inventive implant will now be discussed. In  FIGS. 2A and 2B , the implant  10  of  FIG. 1  is shown in its undeployed orientation. A preferred procedure for deploying the implant is generally similar in many respects to the procedure disclosed in U.S. Patent Application Publication No. 2006/0155287, herein already expressly incorporated by reference. 
         [0093]    Thus, to accomplish tendon fixation using the exemplary methods and devices described herein, standard surgical preparation of the site and/or arthroscopic portals for access to the procedural region are performed. The joint is dilated with arthroscopic fluid if the procedure is to be performed arthroscopically. With open procedures, the device may easily be manipulated and deployed with a single hand. For arthroscopic procedures, the deployment device is introduced through a standard 5, 6, or 8 mm cannula placed into the joint. A range of preferred cannula sizes would be 2-11 mm. 
         [0094]    The procedures described herein are specifically adapted to repair of the ACL in a patient&#39;s knee. However, it should be kept in mind that the implants described herein may be used in numerous other soft tissue repair applications, using surgical procedures which are adapted to those applications. 
         [0095]      FIGS. 8 and 9A  illustrate, from two different orientations, a hamstring ACL reconstruction, wherein the implant  10  is utilized to secure the ACL graft proximal to the femur  60  and distal to the tibia  62  of a patient. To deploy the implant  10 , a bone tunnel  64  is drilled completely through the tibia  62  and partially through the femur  60 . An actuator (not shown) is employed to insert the implant  10  distally through a tibial inlet aperture  66  and through the tibial tunnel  64 , so that the implant  10  is finally disposed in a portion of the tunnel  64  which is within the femur  60 , distal to a femoral aperture  68 , as shown in  FIGS. 8 and 9A . 
         [0096]    Now with respect to  FIGS. 3 and 3A , once the implant  10  is in place within the femoral tunnel  64 , as shown in  FIG. 8 , the deployment screw  12  is actuated (rotated) in order to advance the screw  12  axially distally into the implant body  18 , and thus begin to deploy or expand the compression pads  14  and  16  outwardly.  FIGS. 4 and 4A  depict the next step, wherein advancement of the deployment screw  12  has caused the compression pads  14 ,  16  to fully deploy. As noted above, the screw head or compression pad deployer  34  acts to deploy the compression pads  14 ,  16  as it moves distally into the implant  10 , as shown. 
         [0097]    As the deployment screw  12  continues to move distally through the implant  10 , the distal end of the screw  12 , comprising the male quad lead section  32  ( FIG. 10 ), engages the female quad lead thread  56  of the wedge  20  ( FIG. 14B ). Continued axial distal movement of the screw  12  causes the threaded sections  32  and  56  to cooperate to move the wedge  20  axially in a proximal direction, as shown in  FIG. 5 . This proximal movement of the wedge  20  causes the arms  24  to begin to deploy outwardly. In  FIG. 6 , the wedge  20  is shown in a position where it is about halfway engaged within the separating arms  24 . 
         [0098]    In  FIGS. 7A and 7B , the wedge  20  is fully proximally engaged with the body  12  of the implant  10 , such that the arms  24  are, consequently, fully deployed. In  FIG. 8 , the implant  10  is shown in this fully deployed condition. 
         [0099]      FIGS. 9A and 9B  illustrate tendon compression as effected by the deployed implant  10 . In these figures, tendons  70  are compressed by deployed compression pads  14 ,  16  against the femoral tunnel wall in order to promote tendon-to-bone healing at the aperture of the tunnel. Advantageously, the inventive approach actively compresses the tendons against the bone tunnel. 
         [0100]    Alternative implant designs are shown in  FIGS. 15 and 16 . In particular,  FIGS. 15A and 15B  illustrate an alternative embodiment (with like elements being labeled with like reference numerals to those used in connection with the embodiment of 
         [0101]      FIG. 1 ) wherein the arms  24  are flipped to the other side of the body  18 . The modified arms  24  are designed to permit the tendons (not shown) to pass by them and engage with the cortical bone. The arm-to-body joint is a pin-less design with a track way in the body that secures the arm  24  in place. 
         [0102]      FIGS. 16A and 16B  illustrate yet another modified embodiment wherein, once again, like elements are labeled with like reference numerals as those used in connection with the earlier embodiments. In this embodiment, the implant  10  uses the body  18  as a wedge. 
         [0103]    Testing has been done by the inventors to verify the functionality of the disclosed invention of  FIGS. 1-7 . As shown in  FIG. 17 , the inventors found that pull-out forces for the implant  10  were significantly higher than those of a predicate device, the RCI interference screw available from Smith &amp; Nephew. 
         [0104]    In  FIGS. 18-21  there is shown another implant embodiment  110 , wherein like elements are identified with like reference numerals as for the embodiment of  FIGS. 1-14 , preceded by the numeral  1 . As shown, the deployment screw  112  protrudes through the compression pads  114  and  116 , which are each integrated into the body  118 . The deployment screw  112  is threaded at its distal end into the wedge  120 . Two pins  122  attach a pair of arms  124  to the body  118 , as shown. 
         [0105]    As noted above, in this embodiment the compression pads  114 ,  116  are  25  integrated into the body  118 . This feature permits the use of a shorter implant than is the case for the implant of  FIG. 1 . A track  126  in the wedge  120  attaches to track posts  128  on the arms  124  ( FIG. 29 ), which keep the wedge  120  from rotating during deployment. The compression pads expand as the implant is deployed. In particular, the screw  112  expands the pads  114 ,  116  outwardly by sliding on a compression taper  72  ( FIG. 27 ), as shown in  FIGS. 20-23 . Moreover, as the deployment screw  112  rotates, the wedge  120  expands the arms  124  as also shown in  FIGS. 20-23 . Once the screw  112  is fully seated, the expanded arms  124  fully engage with adjacent cancellous bone  74 , thus locking the anchor in place, as shown in  FIG. 24 . 
         [0106]    The deployment screw  112  ( FIG. 26 ) has a male quad lead section  132  with four separate thread starts, as in the prior disclosed embodiment. This means that for every one rotation of the screw, the linear distance it travels is four times that which a single lead screw would travel. This enables the user to turn the screw fewer times than would be required with a single start thread, approximating the same number of turns that the user would need during the implantation of an interference screw such as the RCI screw available from Smith &amp; Newphew. Oftentimes, during implantation, an interference screw such as the RCI screw requires a notch to be placed at the edge of the femoral tunnel aperture to permit the screw to start engaging the bone. However, the present invention avoids the need for such a step, resulting in an easier implantation procedure. The invention is easy to deploy as an interference screw, and requires fewer steps. The deployment screw  112  also provides a rigid backbone to support the implant. A reverse threaded hex  75  is preferably provided to drive the screw. 
         [0107]    The screw head or compression pad deployer  134  deploys the compression pads  114 ,  116  as the screw  112  advances axially into the implant. Another feature of the screw is the provision of a load transfer disk  136  that transfers some of the axial load from the screw head  134  to body junction to the disk to body junction. This allows for thinner side walls or struts  138  on the body  118  due to the decreased load on the struts, which in turn allows a larger tendon to fit between the deployment screw  112  and the body  118 . 
         [0108]    As shown in  FIG. 25 , the compression pads  114 ,  116  compress the tendons  170  against the femoral tunnel wall to promote tendon-to-bone healing at the aperture of the tunnel. Unlike prior art approaches for more intimate tendon-to-bone contact that only reduce the space between the tendon and the tunnel wall, the present invention actively compresses the tendons against the bone tunnel. The compression pads  114 ,  116  in this embodiment are integral with the body  118 . 
         [0109]    The body  118  functions to trap the tendons  170  on either side of the deployment screw  112 . The struts  138  are split, as shown at reference numeral  76  ( FIG. 28 ), to allow the integrated compression pads  114 ,  116  to expand and compress the tendon against the bone tunnel. They also provide structural support for the deployment screw  112 , wedge  120 , and arms  124  to deploy against. 
         [0110]    The arms  124  include a few key design features, as particularly shown in  FIGS. 29 and 30 . Fins  146  on the top provide torsional strength for the wedge  120  to arm  124  junction. They also allow easier insertion into the femoral tunnel when inserting into a femoral tunnel that is drilled off-axis from the tibial tunnel. The portion of the arm  24  that engages with the bone has a tapered edge  148  which allows for ease of bone displacement during deployment. The support rib  150  along the length of the arm  124  is also tapered for ease of bone displacement and provides structural support during axial loading. The torsion pins  152  engage with a torsion hole  154  to provide additional torsional strength while inserting into the femoral tunnel. 
         [0111]    As in the prior embodiment, the wedge  120  is threaded with a female quad lead thread  156  that matches the complementary threads  132  on the deployment screw  112 . The track posts  128  on the arms  124  engage with the wedge track  126  to provide torsional strength through deployment. A tapered nose  158  allows easier off-axis insertion into the femoral tunnel. 
         [0112]      FIG. 32  is a table similar to that of  FIG. 17 , presenting data generated by the inventors which indicates that pull-out forces for the implant  110  were significantly higher than those of a predicate device, the RCI interference screw available from Smith &amp; Nephew. 
         [0113]    Still another embodiment of the inventive implant is illustrated in  FIGS. 33-54 , wherein like elements to those of the prior embodiments are identified by like reference numerals, preceded by the numeral  2 . This embodiment  210  utilizes the cortical bone for fixation in combination with tendon-to-bone compression. In this version of the invention, the deployment screw  212  is offset to one side of the implant  210 , for the purpose of permitting easier passing of tendon through the orifice. This implant deploys in two steps. The deployment screw  212  is rotated clockwise as an arm  78  and wedge  220  slide together across tapered faces  80  ( FIGS. 46) and 82  ( FIG. 48 ) until they lock together with their respective cortical locks  84 ,  86 . The wedge  220  and the arm  78  lock into place by filling a majority of the cross section of the femoral tunnel. Thus, the implant is free to move in the femoral tunnel, allowing tactile feedback to ensure engagement of a cortical tab  88  with the cortex. 
         [0114]    The screw is then rotated so that it is advanced the remainder of the way, and the compression wedge  90  engages with the compression pads, thereby pressing the tendon against the bone tunnel wall. A track  92 ,  94  in the compression pads  214 ,  216  and compression wedge  90  prevents the compression wedge from  20  engaging unevenly. A progression of deployment of the implant  210  is illustrated in  FIGS. 35-42 .  FIGS. 43-50  illustrate various components of the embodiment. In the undeployed state, the arm is engaged with the wedge with the arm&#39;s track posts  228  engaging with a T-bar  96  of the wedge  220 . This prevents the arm  78  from moving during insertion. Also, to prevent the wedge  220  from rotating during deployment, the track post  228  is inserted into a torsion slot  100 . 
         [0115]    Modified cortical fixation implant designs are illustrated in  FIGS. 51-54 .  FIGS. 51 and 52  illustrate a modified wedge and only one arm which allows engagement with the cortical bone.  FIGS. 53 and 54  illustrate the same embodiments as in  FIGS. 51 and 52 , wherein the screw is to one side of the implant. 
         [0116]      FIG. 55  has been incorporated into this application to illustrate a substantially completed ACL repair procedure.  FIGS. 8 and 9 , as well as  FIGS. 24 and 25  and  FIGS. 41 and 42 , illustrate the installation of the femoral anchor of the present invention, in various embodiments. However, as one skilled in the art would understand, to complete the repair procedure further steps are necessary. Once the femoral anchor has been deployed and installed, as previously described, the anchored tendons  70  extend proximally from the femoral tunnel through the tibial tunnel and out through tibial aperture  66 . To complete the procedure, a tibial anchor  102  is preferably installed, to anchor the tendon bundles in place, as shown in  FIG. 55 . Once this anchor is in place, the proximal ends of the tendon bundles are trimmed to complete the procedure. This portion of the ACL reconstruction procedure is fully explained in co-pending U.S. application Ser. No. 11/725,981, which has already been fully and expressly incorporated by reference herein. Any suitable tibial anchor  102  may be used in conjunction with femoral anchors of the type disclosed in this application, but the tibial anchors shown and described in the &#39;981 patent application are presently preferred. 
         [0117]    Accordingly, although exemplary embodiments of the invention has been  20  shown and described, it is to be understood that all the terms used herein are descriptive rather than limiting, and that many changes, modifications, and substitutions may be made by one having ordinary skill in the art without departing from the spirit and scope of the invention.