Patent Publication Number: US-2021169466-A1

Title: Implant having adjustable filament coils

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of and claims priority to U.S. Patent application Ser. No. 16/051,423, filed Jul. 31, 2018, and entitled “Implant Having Adjustable Filament Coils,” which is a divisional of and claims priority to U.S. patent application Ser. No. 14/986,584, filed Dec. 31, 2015, and entitled “Implant Having Adjustable Filament Coils,” and which issued as U.S. Pat. No. 10,052,094 on Aug. 21, 2018, which is a continuation-in-part of and claims priority to U.S. Pat. No. 13/793,514, filed Mar. 11, 2013, and entitled “Implant Having Adjustable Filament Coils,” and which issued as U.S. Pat. No. 9,974,643 on May 22, 2018, the contents of each which is hereby incorporated by reference in their entireties. 
    
    
     FIELD 
     The present disclosure relates to devices, systems, and methods for securing soft tissue to bone, and more particularly it relates to securing an ACL graft to a femur. 
     BACKGROUND 
     Joint injuries may commonly result in the complete or partial detachment of ligaments, tendons, and soft tissues from bone. Tissue detachment may occur in many ways, e.g., as the result of an accident such as a fall, overexertion during a work related activity, during the course of an athletic event, or in any one of many other situations and/or activities. These types of injuries are generally the result of excess stress or extraordinary forces being placed upon the tissues. 
     In the case of a partial detachment, commonly referred to under the general term “sprain,” the injury frequently heals without medical intervention, the patient rests, and care is taken not to expose the injury to undue strenuous activities during the healing process. If, however, the ligament or tendon is completely detached from its attachment site on an associated bone or bones, or if it is severed as the result of a traumatic injury, surgical intervention may be necessary to restore full function to the injured joint. A number of conventional surgical procedures exist for re-attaching such tendons and ligaments to bone. 
     One such procedure involves forming aligned femoral and tibial tunnels in a knee to repair a damaged anterior cruciate ligament (“ACL”). In one ACL repair procedure, a ligament graft is associated with a surgical implant and secured to the femur. A common ACL femoral fixation means includes an elongate “button,” sometimes referred to as a cortical button. The cortical button is attached to a suture loop that is sized to allow an adequate length of a soft tissue graft to lie within the femoral tunnel while providing secure extra-cortical fixation. 
     Existing devices and methods can be limited because they do not always provide the desired strength. In some instances, one or more knots tied to help maintain a location of the suture loop with respect to a cortical button, and thus the graft associated therewith, can loosen or slip. Thus, even if a ligament graft is disposed at a desired location during a procedure, post-operatively the circumference of the loop can increase, causing the graft to move away from the desired location. Further, it can be desirable to limit the number of knots used in conjunction with such devices, because of the potential for the knots loosening and because the additional surface area knots can increase the risk of trauma. Some existing knot configurations used in conjunction with procedures of this nature can undesirably bind, which can prevent the knot from cinching down and leads to the knot having a higher profile. Still further, existing devices and methods also lack adjustability in many instances. For example, in procedures in which multiple ligament grafts are associated with the cortical button, it can be difficult to control placement of one ligament graft independently (i.e. without also moving the other ligament graft). 
     Accordingly, it is desirable to provide devices, systems, and methods that improve the strength and adjustability of surgical implants used in conjunction with ligament graft insertion, and to minimize the number of knots associated with maintaining a location of the grafts once the grafts are disposed at desired locations. 
     SUMMARY 
     Devices, systems, and methods are generally provided for performing ACL repairs. In one exemplary embodiment, a surgical implant includes a body having a plurality of thru-holes and a suture filament extending through the body. The filament can be configured to form a knot and a plurality of coils, with the knot being located on a top side of the body and a portion of each coil being disposed on both the top side of the body and a bottom side of the body as a result of the filament being disposed through at least two of the plurality of thru-holes of the body. The knot can be a self-locking knot, with the self-locking knot defining a collapsible opening. The knot can have a portion of the suture filament that is intermediate its first terminal end and the plurality of coils and is disposed on the top side of the body passed through the collapsible opening from a first side of the opening. Further, the knot can have a portion of the suture filament that is intermediate its second terminal end and the plurality of coils and disposed on the top side of the body passed through the collapsible opening from a second, opposite side of the opening. In some embodiments, the collapsible opening can be configured to collapse and move toward the body when tension is applied to at least one of the first and second terminal ends. 
     The plurality of coils can include a first coil and a second coil formed by a first portion of the filament extending between the self-locking knot and the first terminal end, and a third coil and a fourth coil formed by a second portion of the filament extending between the self-locking knot and the second terminal end. In some embodiments the thru-holes of the body include two outer thru-holes and two inner thru-holes, with each outer thru-hole being located adjacent to respective opposed terminal ends of the body and the inner thru-holes being disposed between the outer thru-holes. In such embodiments, the first and third coils can pass through each of the outer thru-holes and the second and fourth coils can pass through each of the inner thru-holes. Alternatively, in such embodiments, the first, second, third, and fourth coils can all pass through each of the inner thru-holes. At least one coil can be configured such that its circumference can be changed by applying tension to at least one of the first and second terminal ends. In some embodiments the plurality of coils can be configured such that a circumference of one coil can be adjusted independent from adjusting a circumference of another coil. 
     The self-locking knot can include a Lark&#39;s Head knot. The Lark&#39;s Head knot can have certain modifications or additions to allow it to be self-locking, as described in greater detail herein. In some embodiments the implant can include a second suture filament extending longitudinally through the body. The second suture filament can pass through each thru-hole of the plurality of thru-holes, and can be used, for example, as a shuttle to help guide the implant through a bone tunnel. 
     A sleeve can be included as part of the implant. A sleeve can be disposed over a first portion of the suture filament that extends between the self-locking knot and the first terminal end, and a sleeve can be disposed over a second portion of the suture filament that extends between the self-locking knot and the second terminal end, with each sleeve being located on the top side of the body. In some embodiments the sleeve disposed over the first portion and the sleeve disposed over the second portion can be the same sleeve, with a portion of that sleeve being disposed around the bottom side of the body. 
     Another exemplary embodiment of a surgical implant includes a body having a plurality of thru-holes formed therein and a suture filament attached to the body such that the filament has a first terminal end, a second terminal end, and a Lark&#39;s Head knot formed therein, all of which are located on a top side of the body. The suture filament can be arranged with respect to the body such that a first portion of the filament extending between the Lark&#39;s Head knot and the first terminal end passes through one thru-hole to a bottom side of the body and through a different thru-hole to the top side of the body to form a first loop. Similarly, a second portion of the filament extending between the Lark&#39;s Head knot and the second terminal end passes through one thru-hole to the bottom side of the body and through a different thru-hole to the top side of the body to form a second loop. Further, the first terminal end can pass through an opening defined by the Lark&#39;s Head knot from a first side of the opening and the second terminal end can pass through the same opening from a second, opposite side of the opening. 
     In some embodiments, additional loops can be formed from the suture filament. For example, the suture filament can be arranged with respect to the body such that its first portion passes through one thru-hole to the bottom side of the body and through a different thru-hole to the top side to form a third loop, while its second portion passes through one thru-hole to the bottom side of the body and through a different thru-hole to the top side to form a fourth loop. In some embodiments the thru-holes of the body include two outer thru-holes and two inner thru-holes, with each outer thru-hole being located on an outer portion of the body and the inner thru-holes being disposed between the outer thru-holes. In such embodiments, the first and second portions of the suture filament can pass through each of the outer thru-holes and through each of the inner thru-holes at least once. Alternatively, in such embodiments, the first and second portions of the suture filament can pass through each of the inner thru-holes at least twice. A length of the filament&#39;s first portion and a length of the filament&#39;s second portion can be adjustable. In some embodiments the implant can include a second suture filament extending longitudinally through the body. The second suture filament can pass through each thru-hole of the plurality of thru-holes, and can be used, for example, as a shuttle to help guide the implant through a bone tunnel. 
     One exemplary embodiment of a surgical method includes loading a graft onto one or more coils of a plurality of coils of an implant filament that is coupled to an implant body, pulling a leading end of a shuttle filament that is disposed through the implant body through a bone tunnel until the implant body is pulled out of the tunnel while at least a portion of the implant filament and the graft remain in the tunnel, and orienting the implant body so that its bottom side is facing the bone tunnel through which the implant body passed. Pulling the leading end of the shuttle filament also necessarily pulls the implant body, the implant filament, and the graft through the tunnel. The resulting orientation of the implant&#39;s bottom side facing the tunnel is such that the plurality of coils are disposed substantially within the tunnel and a sliding knot first and second terminal ends of the implant filament are located outside of the tunnel, adjacent to a top side of the implant body. 
     In some embodiments, the step of orienting the implant body can be performed by pulling a trailing end of the shuttle filament. Alternatively, the step of orienting the implant body can be performed by pulling both the leading and trailing ends of the shuttle filament. The method can further include selectively applying tension to at least one of the first and second terminal ends to adjust a circumference of one or more of the coils. 
     Yet another exemplary embodiment of a surgical implant includes a body having a plurality of thru-holes and a filament. The filament has an overhand knot located on a top side of the body and a plurality of loops that extend from the overhand knot towards the body. The overhand knot has a first collapsible opening, a second collapsible opening, and a third collapsible opening. The loops can be a first filament loop, a second filament loop, a third filament loop, and a fourth filament loop, with each filament loop passing through two thru-holes of the plurality of thru-holes, and each filament loop having a distal end disposed on a bottom side of the body. At least two tensioning limbs extend from the overhand knot, in a direction opposite to a direction that the filament loops extend from the overhand knot. A portion of filament of the first filament loop disposed on the top side of the body extends through the first collapsible opening, a portion of filament of the second filament loop disposed on the top side of the body extends through the second collapsible opening, a portion of filament of the third filament loop disposed on the top side of the body extends through the first collapsible opening, and a portion of filament of the fourth filament loop disposed on the top side of the body extends through the third collapsible opening. The first, second, and third collapsible openings are collapsed around, and thus engaged with, the respective filaments extending through the respective openings to form the overhand knot. 
     In some embodiments, the plurality of thru-holes can include two outer thru-holes and two inner thru-holes, with each outer thru-hole being located adjacent to respective opposed terminal ends of the body and the inner thru-holes being disposed between the outer thru-holes. The first and third filament loops can be disposed in each of the outer thru-holes and the second and fourth filament loops can be disposed in each of the inner thru-holes. Alternatively, the first, second, third, and fourth filament loops each can be disposed in each of the inner thru-holes. 
     At least one of the at least two tensioning limbs can be configured to adjust a circumference of at least one of the first, second, third, and fourth filament loops when tension is applied to the limb(s). Further, the first collapsible opening can have a central location such that the second collapsible opening is located on one side of the first collapsible opening and the third collapsible opening is located on a second, approximately opposite side of the first collapsible opening. Moreover, the first, second, third, and fourth filament loops of the recited embodiments can hold a combined average maximum load of at least about 765 N. 
     In a further exemplary embodiment a surgical implant includes a body having a plurality of thru-holes formed therein and a suture filament extending through the body. The suture filament is configured to form an overhand knot located on a top side of the body with the knot having a first collapsible opening, a second collapsible opening, and a third collapsible opening. A first coil is formed by extending a first suture limb from the overhand knot, through a through hole of the plurality of thru-holes formed in the body to a bottom side of the body, then through another through hole formed in the body, and then through the first collapsible opening of the overhand knot. A second coil is similarly formed by extending a second suture limb from the overhand knot, through a through hole of the plurality of thru-holes formed in the body to the bottom side of the body, then through another through hole formed in the body, and then through one of the first, second, and third collapsible openings of the overhand knot. A third coil is formed by extending the first suture limb, which has already passed through the first collapsible opening, through a through hole of the plurality of thru-holes formed in the body to the bottom side of the body, then through another through hole formed in the body, and then through the second collapsible opening of the overhand knot. A portion of the first suture limb that extends through the second collapsible opening forms a first tensioning limb. A fourth coil is likewise formed by extending the second suture limb, which has already passed through one of the first, second, and third collapsible openings, through a through hole of the plurality of thru-holes formed in the body to the bottom side of the body, then through another through hole formed in the body, and then through either the third opening of the overhand knot if the second suture limb did not previously extend through the third opening, or one of the first and second collapsible openings of the overhand knot if the second suture limb did extend through the third opening. A portion of the second suture limb that extends through either the third collapsible opening, or one of the first and second collapsible openings, forms a second tensioning limb. The first, second, and third collapsible openings are collapsed around, and thus engaged with, the respective first and second suture limbs extending through the respective openings to form the overhand knot. 
     In some embodiments the plurality of thru-holes can include two outer thru-holes and two inner thru-holes, with each outer thru-hole being located adjacent to respective opposed terminal ends of the body and the inner thru-holes being disposed between the outer thru-holes. The first and third coils can be disposed in each of the outer thru-holes and the second and fourth coils can be disposed in each of the inner thru-holes. Alternatively, the first, second, third, and fourth coils each can be disposed in each of the inner thru-holes. 
     At least one of the first and second tensioning limbs can be configured to adjust a circumference of at least one of the respective first and third coils and second and fourth coils when tension is applied to the limb(s). Further, the first collapsible opening can have a central location such that the second collapsible opening is located on one side of the first collapsible opening and the third collapsible opening is located on a second, approximately opposite side of the first collapsible opening. Moreover, the first, second, third, and fourth coils of the recited embodiments can hold a combined average maximum load of at least about 765 N. 
     In another exemplary method of configuring a surgical implant, the method can include manipulating a filament to form a knot having a first collapsible opening, a second collapsible opening, and a third collapsible opening, the filament having first and second limbs extending from the knot. The filament is coupled to the implant body by passing the first and second limbs from a first side of an implant body to a second side of the implant body, and then from the second side to the first side of the implant body. Back on the first side, the first limb is passed through the first collapsible opening, and the second limb is passed through one of the first, second, and third collapsible openings. The first and second limbs are again passed from the first side to the second side of the implant body, and from the second side to the first side. The first limb is then passed through one of the second and third collapsible openings, while the second limb is passed through a different collapsible opening of the first, second, and third collapsible openings from which it was passed previously. More specifically, the different collapsible opening is the collapsible opening through which neither the first limb nor the second limb has been passed if neither the first limb nor the second limb has been passed through one of the first, second, and third collapsible openings during the three previously recited passes by the first and second limbs through the first, second, and third collapsible openings. The method further includes collapsing the first, second, and third collapsible openings to engage the first and second limbs passed through the openings with a portion of the filament that forms each of the collapsible openings. 
     In some embodiments the first collapsible opening can have a central location such that the second collapsible opening is located on one side of the first collapsible opening and the third collapsible opening is located on a second, approximately opposite side of the first collapsible opening. The method can further include applying tension to a portion of at least one of the first and second limbs extending from the knot after the first, second, and third openings are collapsed to adjust a circumference of at least one of the respective first, second, third, and fourth coils. 
     The method can be such that a first time the first limb is passed from the first side of the implant body to the second side of the implant body, the first limb can be passed through one opening of a plurality of openings formed in the implant body, and a first time the first limb is passed from the second side of the implant body to the first side of the implant body, the first limb can be passed through another opening of the plurality of openings formed in the implant body, thereby forming a first coil. Further, a first time the second limb is passed from the first side of the implant body to the second side of the implant body, the second limb can be passed through one opening of the plurality of openings formed in the implant body, and a first time the second limb is passed from the second side of the implant body to the first side of the implant body, the second limb can be passed through another opening of the plurality of openings formed in the implant body, thereby forming a second coil. In such embodiments, a second time the first limb is passed from the first side of the implant body to the second side of the implant body, the first limb can be passed through one opening of the plurality of openings formed in the implant body, and a second time the first limb is passed from the second side of the implant body to the first side of the implant body, the first limb can be passed through another opening of the plurality of openings formed in the implant body, thereby forming a third coil. A second time the second limb is passed from the first side of the implant body to the second side of the implant body, the second limb can be passed through one opening of the plurality of openings formed in the implant body, and a second time the second limb is passed from the second side of the implant body to the first side of the implant body, the second limb can be passed through another opening of the plurality of openings formed in the implant body, thereby forming a fourth coil. 
     The plurality of openings formed in the implant body can include two outer openings and two inner openings, with each outer opening being located adjacent to respective opposed terminal ends of the implant body and the inner openings being disposed between the outer openings. A portion of the first and second limbs that respectively form the first and second coils can be disposed in each of the inner thru-holes and a portion of the first and second limbs that respectively form the third and fourth coils can be disposed in each of the outer thru-holes. Alternatively, the plurality of openings can include two openings, and a portion of the first and second limbs that respectively form the first and third coils and the second and fourth coils can be disposed in each of the two openings. 
     In some embodiments, a first time the first limb is passed from the first side of the implant body to the second side of the implant body, the first limb can be passed around a first lateral side of the implant body, and a first time the first limb is passed from the second side of the implant body to the first side of the implant body, the first limb can be passed around a second lateral side of the implant body that is opposed to the first lateral side, thereby forming a first coil. Likewise, a first time the second limb is passed from the first side of the implant body to the second side of the implant body, the second limb can be passed around one of the first and second lateral sides of the implant body, and a first time the second limb is passed from the second side of the implant body to the first side of the implant body, the second limb can be passed around the other of the first and second lateral sides of the implant body, thereby forming a second coil. In such embodiments, a second time the first limb is passed from the first side of the implant body to the second side of the implant body, the first limb can be passed around one of the first and second lateral sides of the implant body, and a second time the first limb is passed from the second side of the implant body to the first side of the implant body, the first limb can be passed around the other of the first and second lateral sides of the implant body, thereby forming a third coil. Likewise, in such embodiments, a second time the second limb is passed from the first side of the implant body to the second side of the implant body, the second limb can be passed around one of the first and second lateral sides of the implant body, and a second time the second limb is passed from the second side of the implant body to the first side of the implant body, the second limb can be passed around the other of the first and second lateral sides of the implant body, thereby forming a fourth coil. 
     Unless otherwise specified, the steps of the methods provided for in the present disclosure can be performed in any order. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       This invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1A  is a schematic view of components of one exemplary embodiment of a surgical implant, including a cortical button and a suture filament having a Lark&#39;s Head knot formed therein; 
         FIG. 1B  is a perspective side view of one exemplary embodiment of a surgical implant formed using the cortical button and suture filament of  FIG. 1A ; 
         FIG. 2A  is a top perspective view of the cortical button of  FIG. 1A ; 
         FIG. 2B  is an end elevational view of the cortical button of  FIG. 2A ; 
         FIG. 2C  is a side elevational view of the cortical button of  FIG. 2A ; 
         FIGS. 3A-3E  are sequential views illustrating one exemplary embodiment for forming the Lark&#39;s Head knot of  FIG. 1A ; 
         FIG. 4  is a schematic side cross-sectional view of one exemplary embodiment of a surgical implant; 
         FIG. 5  is a schematic side cross-sectional view of another exemplary embodiment of a surgical implant; 
         FIGS. 6A-6B  are sequential views of yet another exemplary embodiment of a surgical implant, the implant having grafts associated therewith, illustrating selective movement of the grafts; 
         FIGS. 7A-7E  are sequential views illustrating one exemplary embodiment of coupling a suture to a cortical button to form a surgical implant; 
         FIG. 8A-D  are sequential views illustrating one exemplary embodiment of coupling a suture to an implant; 
         FIG. 9A  is a schematic side cross-sectional view of another exemplary embodiment of a surgical implant; 
         FIG. 9B  is a side perspective view of the surgical implant of  FIG. 9A  with a knot of the implant in a collapsed configuration; 
         FIG. 10  is a schematic side cross-sectional view of another exemplary embodiment of a surgical implant; 
         FIGS. 11A-11H  are sequential views illustrating another exemplary embodiment of coupling a suture to a cortical button to form a surgical implant, and associating a graft therewith; 
         FIG. 12  is a side perspective view of another exemplary embodiment of a surgical implant; 
         FIG. 13  is a side perspective view of one exemplary embodiment of a surgical implant associated with a shuttle filament; 
         FIG. 14A  is a schematic side cross-sectional view of another exemplary embodiment of a surgical implant associated with a shuttle filament; 
         FIG. 14B  is a top view of a body of the surgical implant of  FIG. 14A ; 
         FIG. 15A  is a schematic side cross-sectional view of still another exemplary embodiment of a surgical implant associated with a shuttle filament; 
         FIG. 15B  is a top view of a body of the surgical implant of  FIG. 15A ; 
         FIG. 16A  is a schematic view of a portion of one exemplary embodiment for implanting a graft in a bone tunnel using a surgical implant having a shuttle filament associated therewith; 
         FIG. 16B  is a schematic view of the surgical implant of  FIG. 15A  for use in the exemplary embodiment for implanting a graft in a bone tunnel of  FIGS. 16A and 16D -H; 
         FIG. 16C  is a schematic view of the surgical implant of  FIG. 14A  for use in the exemplary embodiment for implanting a graft in a bone tunnel of  FIGS. 16A and 16D -H; 
         FIGS. 16D-G  are schematic, sequential views illustrating the remainder of the exemplary embodiment for implanting a graft in a bone tunnel of  FIG. 16A ; and 
         FIG. 16H  is a schematic view of a portion of another exemplary embodiment for implanting a graft in a bone tunnel using a surgical implant having two, independently collapsible coils. 
     
    
    
     DETAILED DESCRIPTION 
     Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention. Further, in the present disclosure, like-numbered components of the embodiments generally have similar features. Additionally, to the extent that linear or circular dimensions are used in the description of the disclosed systems, devices, and methods, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such systems, devices, and methods. A person skilled in the art will recognize that an equivalent to such linear and circular dimensions can easily be determined for any geometric shape. Sizes and shapes of the systems and devices, and the components thereof, can depend at least on the anatomy of the subject in which the systems and devices will be used, the size and shape of components with which the systems and devices will be used, and the methods and procedures in which the systems and devices will be used. 
     The figures provided herein are not necessarily to scale. Further, to the extent arrows are used to describe a direction a component can be tensioned or pulled, these arrows are illustrative and in no way limit the direction the respective component can be tensioned or pulled. A person skilled in the art will recognize other ways and directions for creating the desired tension or movement. Likewise, while in some embodiments movement of one component is described with respect to another, a person skilled in the art will recognize that other movements are possible. By way of non-limiting example, in embodiments in which a sliding knot is used to help define a collapsible loop, a person skilled in the art will recognize that different knot configurations can change whether moving the knot in one direction will cause a size of an opening defined by the knot will increase or decrease. Additionally, a number of terms may be used throughout the disclosure interchangeably but will be understood by a person skilled in the art. By way of non-limiting example, the terms “suture” and “filament” may be used interchangeably. 
     The present disclosure generally relates to a surgical implant for use in surgical procedures such as ACL repairs. The implant can include a body having thru-holes formed therein and a suture filament associated therewith. An exemplary embodiment of a body  10  and a suture filament  50  illustrated separately is shown in  FIG. 1A , while an exemplary embodiment of the two components coupled together to form an implant  100  is shown in  FIG. 1B . The suture filament  50  can form a self-locking knot  52 , illustrated as including a Lark&#39;s Head knot in  FIG. 1A , and first and second tails  54 ,  55  extending therefrom can be passed through thru-holes  24  formed in the body  10  to associate the two components. As described below, the self-locking knot  52  is actually a Lark&#39;s Head knot modified to make it self-locking. 
     While the particulars of the formation of the construct illustrated in  FIG. 1B  are discussed in greater detail below, as shown the self-locking knot  52  can be formed on a first, top side  10   a  of the body  10  and a plurality of coils  60  formed from the first and second tails  54 ,  55  extending from the self-locking knot  52  can be disposed on a second, bottom side  10   b  of the body  10 . First and second terminal ends  54   t ,  55   t  of the first and second tails  54 ,  55  can be passed through a collapsible opening  56  ( FIGS. 4 and 5 ) of the self-locking knot  52  before the knot  52  is collapsed, with the second terminal end  55   t  passing through the collapsible opening  56  from a first side  56   a  of the opening  56 , and the first terminal end  54   t  passing through the collapsible opening  56  from a second, opposite side  56   b  of the opening  56 . As shown, the terminal ends  54   t ,  55   t  can extend proximally from the self-locking knot  52 , and the collapsible opening  56  can be configured to collapse and move toward the body  10  when tension is applied to at least one of the terminal ends  54   t ,  55   t . Applying tension to the terminal ends  54   t ,  55   t  can also selectively adjust a circumference of one or more of the coils  60  without adjusting a circumference of all of the coils  60 . Optionally, a sleeve  58  can be associated with one or both of the tail portions extending between the self-locking knot  52  and the first and second terminal ends  54   t ,  55   t . The sleeve  58  can help prevent the tails  54 ,  55  from being cut too close to the knot  52  after a desired implant location is achieved. 
     A body  10  for use as a part of a surgical implant to fixate a ligament graft in bone is illustrated in  FIGS. 2A-2C . The body  10  can have a somewhat rectangular, elongate shape with curved leading and trailing terminal ends  16 ,  18 . A plurality of thru-holes  24  can extend from a first, top surface  20  and through a second, bottom surface  22 . In the illustrated embodiment there are two outer thru-holes  24   a ,  24   d  disposed, respectively, adjacent to leading and trailing terminal ends  16 ,  18 , and two inner thru-holes  24   b ,  24   c  disposed between the two outer holes  24   a ,  24   d . As shown, the outer and inner thru-holes  24   a ,  24   d  and  24   b ,  24   c  have diameters that are substantially the same, and a space separating adjacent thru-holes  24  is substantially the same for each adjacent pair. A width W of the body  10  is defined by the distance between the two elongate sidewalls  12 ,  14 , as shown in  FIG. 2B , a length L of the body  10  is defined by the distance between central portions  16   c ,  18   c  of the end walls of the leading and trailing terminal ends  16 ,  18 , as shown in  FIG. 2C , and a thickness T of the body  10  is defined by the distance between the top and bottom surfaces  20 ,  22 , as shown in  FIGS. 2B and 2C . The body  10  can generally be referred to as a cortical button, among other known terms. 
     A person skilled in the art will recognize that the body  10  described herein is merely one example of a body that can be used in conjunction with the teachings provided herein. A body configured to be associated with a suture filament of the type described herein can have a variety of different shapes, sizes, and features, and can be made of a variety of different materials, depending, at least in part, on the other components with which it is used, such as the suture filament and the ligament graft, and the type of procedure in which it is used. Thus, while in the present embodiment the body  10  is somewhat rectangular having curved ends, in other embodiments the body can be substantially tubular, among other shapes. 
     In one exemplary embodiment of the substantially rectangular button, the length L of the body is in the range of about 5 millimeters to about 30 millimeters, the width W is in the range of about 1 millimeter to about 10 millimeters, and the thickness T is in the range of about 0.25 millimeters to about 3 millimeters. In one exemplary embodiment, the length L can be about 12 millimeters, the width W can be about 4 millimeters, and the thickness T can be about 1.5 millimeters. Diameters of the thru-holes  24  can be in the range of about 0.5 millimeters to about 5 millimeters, and in one exemplary embodiment each can be about 2 millimeters. Although in the illustrated embodiment each of the thru-holes  24   a ,  24   b ,  24   c ,  24   d  has a substantially similar diameter, in other embodiments some of the thru-holes can have different diameters. Additionally, any number of thru-holes can be formed in the body  10 , including as few as two. 
     In exemplary embodiments the body  10  can be made from a stainless steel or titanium, but any number of polymers, metals, or other biocompatible materials in general can be used to form the body. Some non-limiting examples of biocompatible materials suitable for forming the body include a polyether ether ketone (PEEK), bioabsorbable elastomers, copolymers such as polylactic acid-polyglycolic acid (PLA-PGA), and bioabsorbable polymers such as polylactic acid. The implant can also be formed of absorbable and non-absorbable materials. Other exemplary embodiments of a body or cortical button that can be used in conjunction with the teachings herein are described at least in U.S. Pat. No. 5,306,301 of Graf et al., the content of which is incorporated by reference herein in its entirety. 
     Steps for configuring the suture filament  50  for use as a part of the surgical implant  100  to fixate a ligament graft in bone are illustrated in  FIGS. 3A-3E . As shown in  FIG. 3A , the filament can be folded substantially in half at an approximate midpoint  50   m  of the filament  50 , forming a first filament limb  54  and a second filament limb  55  having first and second terminal ends  54   t  and  55   t , respectively. A central portion  50   c  of the filament  50 , which includes the midpoint  50   m , can be folded toward the first and second limbs  54 ,  55 , as shown in  FIG. 3B , and be brought proximate to the first and second limbs  54 ,  55 . This results in the formation of a first secondary loop  57  and a second secondary loop  59 , as shown in  FIG. 3C . A size of the secondary loops  57 ,  59 , and a length of the limbs  54 ,  55  extending therefrom, can be adjusted as desired. 
     As shown in  FIG. 3D , a portion  54   p ,  55   p  of the first and second limbs  54 ,  55  that are part of the secondary loops  57 ,  59  can be grasped and pulled upward (as shown, “out of the page”). This results in the configuration illustrated in  FIG. 3E , a filament having a Lark Head&#39;s knot  52  formed therein with first and second filament limbs  54 ,  55  having terminal ends  54   t ,  55   t  extending therefrom. The Lark&#39;s Head knot  52  defines a collapsible opening  56 , a size of which can be decreased by applying a force in an approximate direction A to one or both of the limbs  54 ,  55  extending from the knot  52 , or by applying a force in an approximate direction B to the opening  56 . Likewise, a size of the opening  56  can be increased by grasping near the midpoint  50   m  of the filament  50  to hold the portion where the fold is formed approximately stationary and then applying either a force in the approximate direction B to both of the limbs  54 ,  55  extending from the knot  52 , or a force in the approximate direction B to the opening  56 . As described in greater detail below, the Lark&#39;s Head knot can be modified to form a self-locking knot. 
     A person skilled in the art will recognize other ways by which a Lark&#39;s Head knot can be formed. Similarly, a person skilled in the art will be familiar with other types of knots that can be formed in suture filaments, and will understand ways in which other knots can be adapted for use in a manner as the Lark&#39;s Head knot is used in the present disclosure. The present disclosure is not limited to use only with a Lark&#39;s Head knot. 
     The suture filament  50  can be an elongate filament, and a variety of different types of suture filaments can be used, including but not limited to a cannulated filament, a braided filament, and a mono filament. The type, size, and strength of the filament can depend, at least in part, on the other materials of the implant, including the material(s) of the cortical button and the ligament graft, the tissue, bone, and related tunnels through which it will be passed, and the type of procedure in which it is used. In one exemplary embodiment the filament is a #0 filament (about 26 gauge to about 27 gauge), such as an Orthocord™ filament that is commercially available from DePuy Mitek, LLC., 325 Paramount Drive, Raynham, Mass. 02767, or an Ethibond™ filament that is commercially available from Ethicon, Inc., Route 22 West, Somerville, N.J. 08876. The thickness of the filament should provide strength in the connection but at the same time minimize the trauma caused to tissue through which it passes. In some embodiments the filament can have a size in the range of about a #5 filament (about 20 gauge to about 21 gauge) to about a #3-0 filament (about 29 gauge to about 32 gauge). Orthocord™ suture is approximately fifty-five to sixty-five percent PDS™ polydioxanone, which is bioabsorbable, and the remaining thirty-five to forty-five percent ultra high molecular weight polyethylene, while Ethibond™ suture is primarily high strength polyester. The amount and type of bioabsorbable material, if any, utilized in the filaments of the present disclosure is primarily a matter of surgeon preference for the particular surgical procedure to be performed. In some exemplary embodiments, a length of the filament can be in the range of about 0.2 meters to about 5 meters, and in one embodiment it has a length of about 1.5 meters. 
       FIG. 4  illustrates one exemplary embodiment of the suture filament  50  being associated with the body  10  to form a surgical implant  100 ′. As shown, the Lark&#39;s Head knot  52  is disposed on a first, top side  10   a  of the body  10 , and the limbs  54 ,  55  extending therefrom are used to associate the filament  50  with the body  10 . The limbs  54 ,  55  can be selectively passed through one of the thru-holes  24  to a bottom side  10   b  of the body  10 , and then through another of the thru-holes  24  back to the top side  10   a . In the illustrated embodiment, the first limb  54  passes through the second thru-hole  24   b  to reach the bottom side  10   b  and then through the third thru-hole  24   c  to reach the top side  10   a , while the second limb  55  passes through the third thru-hole  24   c  to reach the bottom side  10   b  and then through the second thru-hole  24   b  to reach the top side  10   a , forming a coil or loop  60   a  of the first limb  54  and a coil or loop  60   b  of the second limb  55 . The terminal ends  54   t ,  55   t  of the limbs  54 ,  55  can then be passed through the opening  56  defined by the Lark&#39;s Head knot  52 . As shown, the terminal end  54   t  can be passed from the second side  56   b  of the opening  56 , as shown a right side, through the opening  56 , and to a first side  56   a  of the opening  56 , as shown a left side, while the terminal end  55   t  can be passed from the first side  56   a , through the opening  56 , and to the second, opposite side  56   b . The limbs  54 ,  55  can continue to be pulled through the opening  56  until a desired coil size for each of the first and second limbs  54 ,  55  is achieved. In alternative embodiments, one or both of the limbs  54 ,  55  can be passed through the opening  56  multiple times before using the limbs  54 ,  55  to adjust the coils  60  to the desired size. 
     Once the terminal ends  54   t ,  55   t  have been passed through the opening  56  and the desired coil size has been achieved, the opening  56  can be collapsed. One way that the opening  56  can be collapsed is by applying a force to the terminal ends  54   t ,  55   t  in an approximate direction C as shown, while also applying a counterforce to the coils  60  to approximately maintain the circumference of the coils. Without the counterforce, the force in the approximate direction C would typically decrease the circumference of the coils  60  before collapsing the opening  56 . Because the terminal ends  54   t ,  55   t  are passed through opposing sides  56   a ,  56   b  of the opening  56 , and compression of the Lark&#39;s Head knot  52  against a top surface  20  of the body  10  creates resistance against loosening, the resulting collapsed knot is self-locking, meaning the Lark&#39;s Head knot  52  is a sliding knot that locks itself without the aid of additional half-hitches or other techniques known to help secure a location of a knot with respect to the body  10 . 
     After the opening  56  is collapsed, a circumference of the coils  60  can again be decreased by applying force to the terminal ends  54   t ,  55   t  in the approximate direction C with the first terminal end  54   t  generally controlling the size of the coil  60   a  and the second terminal end  55   t  generally controlling the size of the coil  60   b . Because the collapsible opening  56  is self-locking, it can be more difficult to increase a circumference of the coils  60   a ,  60   b  after the opening  56  is collapsed. However, a person skilled in the art will understand how portions of the filament  50  that form the collapsible knot  52  can be manipulated to allow for increases in the circumference of the coils  60   a ,  60   b.    
     In other embodiments, more than one coil can be formed by the first or second filament limbs. One exemplary embodiment of such an implant  100 ″ is shown in  FIG. 5 . Similar to the implant  100 ′, the Lark&#39;s Head knot  52  is disposed on the top side  10   a  of the body  10 , and the limbs  54 ,  55  extending therefrom are selectively passed through multiple thru-holes  24  of the body  10  to associate the filament  50  with the body  10 . In the illustrated embodiment, the first limb  54  passes distally through the second hole  24   b  to the bottom side  10   b  of the body  10 , and through the third thru-hole  24   c  back to the top side  10   a  twice to form a first coil  60   a  and a second coil  60   c  before it is then passed through the opening  56  defined by the Lark&#39;s Head knot  52  from the second side  56   b  of the opening  56  to the first side  56   a . Similarly, the second limb  55  passes distally through the third hole  24   c  to the bottom side  10   b , and through the second thru-hole  24   b  back to the top side  10   a  twice to form a first coil  60   b  and a second coil  60   d  before it is then passed through the opening  56  from the first side  56   a  to the second side  56   b . The opening  56  can be collapsed, and a circumference of the first and second coils  60   a ,  60   c  can be adjusted by the terminal end  54   t  and the first and second coils  60   b ,  60   d  can be adjusted by the terminal end  55   t  in manners similar to those described above with respect to the device  100 ′. The inclusion of a second coil formed from the limbs  54 ,  55  increases the strength of the implant  100 ″ due to a pulley effect, allowing the implant  100 ″ to be more stable when it is implanted in bone and to more stably hold a ligament graft attached to one or more of the coils  60 . 
     Any number of coils can be formed from the first and second limbs  54 ,  55 , and the number of coils formed in the first limb  54  does not have to be the same number of coils formed in the second limb  55 . In some exemplary embodiments, three or four coils can be formed in one or both of the limbs. Further, the limbs used to form the coils can be passed through any number of thru-holes formed in the body  10 . The first limb  54  does not need to pass through the same thru-holes through which the second limb  55  passes. Accordingly, by way of non-limiting example, a coil of the first limb  54  can be formed by passing the limb through the first thru-hole  24   a  and then back through the fourth thru-hole  24   d  and a coil of the second limb  55  can be formed by passing the limb through the third thru-hole  24   c  and then back through the second thru-hole  24   b . By way of further non-limiting example, a coil of the first limb  54  can be formed by passing the limb through the second thru-hole  24   b  and then back through the fourth thru-hole  24   d  and a coil of the second limb  55  can be formed by passing the limb through the third thru-hole  24   c  and then back through the second-thru hole  24   b.    
     Likewise, when multiple coils are formed in one limb, that limb does not have to be passed through the same thru-holes to form each coil. Accordingly, by way of non-limiting example, a first coil of the first limb  54  can be formed by passing the limb through the second thru-hole  24   b  and then back through the third thru-hole  24   c  and a second coil of the first limb  54  can be formed by passing the limb through the first thru-hole  24   a  and then back through the fourth thru-hole  24   d . By way of further non-limiting example, a first coil of the second limb  55  can be formed by passing the limb through the fourth thru-hole  24   d  and then back through the first thru-hole  24   a  and a second coil of the second limb  55  can be formed by passing the limb through the fourth thru-hole  24   d  and then back through the second thru-hole  24   b . In yet one further non-limiting example, a coil of the first limb  54  can be passed through the second thru-hole  24   b  and then back through the second thru-hole  24   b  and a coil of the second limb  55  can be passed through the third thru-hole  34   c  and then back through the third thru-hole  24   c , with the first limb  54  and the second limb  55  intersecting at least once on the bottom side  10   b  so that the limbs  54 ,  55  remain on the bottom side  10   b  when they are passed back through the same thru-hole they came to reach the bottom side  10   b  in the first place. A person skilled in the art will recognize a number of configurations between the filament and thru-holes that can be used to form one or more coils in the filament limbs before disposing terminal ends of the limbs through a collapsible opening of a knot to create a self-locking knot. 
     A variety of tests were performed to assess the strength and integrity of an implant having a self-locking knot and four coils like some of the embodiments provided for herein. In particular, the tests were performed on the implant  100  shown in  FIG. 2 , with the filament being a braided #2 ultra high molecular weight polyethylene suture with a loop circumference of approximately 40 millimeters. Three separate cycle tests of varying length were performed. Generally, a cyclical load was applied to the implant  100  a plurality of times, with the load cycling between about 50 Newtons and about 250 Newtons. After a certain number of cycles were performed, the distance a graft migrated from its original position was measured. After 10 cycles a displacement of the implant  100  was about 1.0 mm, after 750 cycles a displacement of the implant was about 1.4 millimeters, and after 1000 cycles a displacement of the implant was about 1.4 millimeters. Further details about testing protocols of this nature can be found in an article written by Kamelger et al., entitled “Suspensory Fixation of Grafts in Anterior Cruciate Ligament Reconstruction: A Biomechanical Comparison of 3 Implants,” published in  Arthroscopy , Jul. 25, 2009, pp. 767-776, and in an article written by Petre et al., entitled “Femoral Cortical Suspension Devices for Soft Tissue Anterior Cruciate Ligament Reconstruction,” published in  The American Journal of Sports Medicine , February 2013, pp. 416-422, the content of each which is incorporated by reference herein in its entirety. A person skilled in the art will recognize that the test results are dependent at least on the type and size of the filament of the implant. 
     Another test determined an ultimate failure load of the implant  100 . The ultimate failure load measures the load at which the implant  100  fails. The ultimate failure load tested for the implant  100  was about 1322 Newtons. During the ultimate failure load test, the displacement at 450 Newtons was also measured, with displacement being about 2.0 millimeters. Still another test performed on the implant was a regression stiffness test, which plots the displacement of the implant in comparison to the load and a slope of the initial line is measured. The implant  100  demonstrated a regression stiffness of about 775 Newtons per millimeter. Again, a person skilled in the art will recognize that these test results are dependent at least on the type and size of the filament of the implant. 
       FIGS. 6A and 6B  illustrate the ability to selectively control some coils  60   a ′,  60   c ′ of an implant  100 ″′ using one limb  54 ′ and other coils  60   b ′,  60   d ′ of the implant  100 ″′ using the other limb  55 ′. As shown, the implant  100 ″′ includes a single filament  50 ′ associated with a body  10 ′ having a plurality of thru-holes  24 ′ formed therein. The configuration between the filament  50 ′ and the body  10 ′ is similar to the implants  100 ,  100 ″ described above with respect to  FIGS. 2 and 5 . As shown, a self-locking knot  52 ′ is formed on a top side  10   a ′ of the body  10 ′ and four coils  60 ′ are formed from first and second limbs  54 ′,  55 ′ extending from the self-locking knot  52 ′, the four coils  60 ′ being substantially disposed on a bottom side  10   b ′ of the body  10 ′. Terminal ends  54   t ′,  55   t ′ of the first and second limbs  54 ′,  55 ′ pass through an opening  56 ′ of the self-locking knot  52 ′ before the knot is collapsed, and can be used to adjust a circumference of the coils  60 ′. In the illustrated embodiment, the first limb  54 ′ is differentiated from the second limb  55 ′ by including markings on the first limb  54 ′. These visual indicators allow a surgeon to easily know which coils are controlled by which limbs, and can be added to the filament before or after the filament is associated with the body  10 ′. 
     In the illustrated embodiment, a first ligament graft  102 ′ is coupled to first and second coils  60   a ′,  60   c ′ of the first limb  54 ′ by wrapping the graft  102 ′ through each of the first and second coils  60   a ′,  60   c ′, and a second ligament graft  104 ′ is coupled to first and second coils  60   b ′,  60   d ′ of the second limb  55 ′ by wrapping the graft  104 ′ through each of the first and second coils  60   b ′,  60   d ′. As shown in  FIGS. 6A and 6B , applying a force to the first limb  54 ′ in an approximate direction D decreases the circumference of the first and second coils  60   a ′,  60   c ′, thereby drawing the first ligament graft  102 ′ closer to the body  10 ′. More particularly, as tension is created by the force, the circumference of the diameter of the second coil  60   c ′ decreases and advances the first graft  102 ′. As the distance between distal ends of the second coil  60   c ′ and the first coil  60   a ′ increases, the weight of the graft  102 ′ helps create a counterforce that maintains the circumference of the second coil diameter while the circumference of the first coil  60   a ′ decreases to catch-up to the second coil  60   c ′ and the graft  102 ′. A person skilled in the art will understand how the application of various forces and tensions to the first and second limbs  54 ′,  55 ′, the first and second coils  60   a ′,  60   c ′ and  60   b ′,  60   d ′, and the first and second grafts  102 ′,  104 ′ associated therewith can be manipulated to selectively adjust locations of the grafts  102 ′,  104 ′ with respect to the body  10 ′. 
     As a result of this configuration, one ligament graft can be pulled closer the body  10 ′ than another ligament graft. Such graft configurations can be useful to surgeons. By way of non-limiting example, if during the course of a tissue repair the surgeon accidentally amputated one of the hamstring tendons during harvesting or graft preparation, the coils associated with one of the terminal ends can be adjusted so that the longer tendon is pulled deeper into the femoral tunnel with the shorter tendon being more proximal of the longer tendon, thus leaving more graft for the tibial tunnel. By way of further non-limiting example, grafts can be independently tensioned such that they are tightest at different angles of knee flexion, which can provide superior biomechanics due to the repair being more anatomic. Other configurations that can permit selective, independent tightening of the coils formed in the suture filament can also be used while maintaining the spirit of the present disclosure. For example, two separate knot or finger-trap mechanisms can be disposed through the same thru-holes in the button to permit selective, independent control of the coils. 
     Four non-limiting alternative embodiments for associating a suture filament  150 ,  250 ,  950 ,  950 ′ with a cortical button  110 ,  210 ,  910 ,  910 ′ to form an implant  200 ,  300 ,  900 ,  900 ′ are illustrated in  FIGS. 7A-7E ,  FIGS. 11A-11H ,  FIGS. 9A-9B , and  FIG. 10  respectively. Further,  FIGS. 8A-D  illustrate an embodiment for associating a suture filament  850  with an implant  870 . Starting first with  FIGS. 7A-7E , the cortical button  110  includes four thru-holes  124  disposed therein and the suture filament  150  is a braided suture. After forming a pretzel-shaped knot  152  using techniques known to those skilled in the art, first and second terminal ends  154   t ,  155   t  of the filament  150  can be passed through the two interior thru-holes  124  of the body  110 , as illustrated in  FIG. 7A , to form two loops or coils  160   a ,  160   b  for receiving a ligament graft. In this embodiment, both the first and second limbs  154 ,  155  pass through the same interior thru-hole  124  to pass from a top side  110   a  to a bottom side  110   b  of the body  110 . Likewise, both limbs  154 ,  155  pass through the same interior thru-hole  124  to pass from the bottom side  110   b  back to the top side  110   a.    
     As shown in  FIG. 7B , the terminal ends  154   t ,  155   t  can be passed through openings of the pretzel-shaped knot  152 . Other suitable sliding knots can be used in lieu of a pretzel-shaped knot. Subsequently, a force can be applied to the terminal ends  154   t ,  155   t  in an approximate direction E to collapse and advance the knot  152  towards a top surface  120  of the body  110 , as shown in  FIG. 7C . The pretzel knot  152  is not generally self-locking. Accordingly, as shown in  FIG. 7D , one or more half-hitches  161  can be formed in the terminal ends  154   t ,  155   t  to secure and lock a location of the collapsed pretzel knot  152  with respect to the body  110 . A graft  202  can then be disposed within openings of the coils  160   a ,  160   b  formed by the first and second limbs  154 ,  155 , as shown in  FIG. 7E . 
     Tests performed using an implant like the embodiment shown in  FIG. 7E , the filament being a braided #5 ultra high molecular weight polyethylene suture with a loop circumference of approximately 40 millimeters, yielded a 10 th  cycle displacement of approximately 1.9 millimeters, a 750 th  cycle displacement of approximately 2.2 millimeters, and a 1000 th  cycle displacement of approximately 2.3 millimeters. The ultimate failure load was measured to be approximately 1521 Newtons. Displacement at a load of 800 Newtons was measured to be approximately 4.1 millimeters. Meanwhile, the regression stiffness was determined to be approximately 267 Newtons per millimeter. A person skilled in the art will recognize that the test results are dependent at least on the type and size of the filament of the implant. 
     While the present disclosure provides the formation of a variety of knots that can be used in conjunction with surgical implants,  FIGS. 8A-D  illustrate one exemplary embodiment of a knot formation that is particularly strong and has a particularly low profile. In the illustrated embodiment, a suture  850  is tied directly onto an implant having no holes formed therein because the illustrations are intended to focus on the knot formation. A person having ordinary skill in the art will understand how to incorporate the knot formation into a cortical button or other implants in view of the present disclosure. 
     As shown in  FIG. 8A , suture  850  can be formed into a pretzel, or overhand, cinch knot  852  having suture limbs  854 ,  855  extending therefrom. The knot  852  can have three collapsible openings  852   a ,  852   b , and  852   c . In the illustrated embodiment of  FIG. 8A , the first collapsible opening  852   a  is in a central location of the knot  852 , and the second and third collapsible openings  852   b ,  852   c  are located on opposite sides from the first collapsible opening  852   a.    
     An implant  870  can be placed over the suture limbs  854 ,  855  such that the suture limbs can be wrapped around the implant  870  from a top side  870   a  to a bottom side  870   b  of the implant  870 , thereby creating first and second filament loops, or coils,  860   a ,  860   b , respectively. The terminal ends (not visible) of the suture limbs  854 ,  855  are then passed through the first collapsible opening  852   a  from a front side of the knot  852  to a rearward side of the knot, as shown in  FIG. 8B . 
     The suture limbs  854 ,  855  are next passed from the top side  870   a  of the implant  870  around the implant  870  to the bottom side  870   b  of the implant  870  and back up to the top side  870   a  of the implant  870  to create the third and fourth filament loops  860   c ,  860   d , respectively, as shown in  FIG. 8C . The terminal ends of the suture limbs  854 ,  855  are then passed through the second and third collapsible openings  852   b ,  852   c , respectively. 
     The knot  852  can be cinched down using any technique known to those skilled in the art or otherwise provided for in any embodiment of the present disclosure. In the illustrated embodiment, to effectively illustrate the low profile of the knot when fully cinched, the loops  860   a - 860   d  are collapsed around the implant  870  as shown in  FIG. 8D . Collapsing of the knot  852  and the loops  860   a - 860   d  can be achieved, for example, by maintaining tension on the limbs  854 ,  855  in the directions R, S, respectively, while applying tension to the loops  860   a - 860   d  in the opposite directions, R′, S′. The loops  860   a - 860   d  can be operated in a manner similar to loops of other configurations provided for herein, including but not limited to loops  60   a - 60   d ,  60   a ′- 60   d ′,  160   a  and  160   b ,  260   a  and  260   b ,  360 ,  460   a  and  460   b ,  560   a - 560   d ,  660   a - 660   d ,  760   a  and  760   b , and  760   a ′- 760   d ′, and thus graft  870  can be inserted within an opening(s)  861   a - 861   d  defined by the loop(s)  860   a - 860   d  even if the loops  860   a - 860   d  are collapsed tightly around the implant  870  as shown in  FIG. 8D . Likewise, while  FIG. 8D  illustrates the loops  860   a - 860   d  are collapsed around the implant  870 , in other embodiments, one or more of the loops  860   a - 860   d  can not be fully collapsed, such as described with respect to the many implants provided for herein (e.g., by way of non-limiting examples, implants  100 ′,  200 ). Further, the knot configuration as illustrated by  FIGS. 8A-8D  can be used in the other configurations of implants provided for herein or otherwise known to those skilled in the art. 
     Further, in yet other embodiments, any multiple of loops can be created by passing the suture limbs  854 ,  855  around the implant  870  as many times as needed. Further still, the suture limbs can be passed through any of the collapsible openings  852   a - 852   c  in any order when creating the filament loops  860   a ,  860   b ,  860   c ,  860   d . By way of non-limiting examples, two limbs can be passed through openings  852   b  or  852   c  instead of opening  852   a , and/or the limbs can be passed through different openings during both passes instead of the same opening during one pass. 
       FIGS. 9A and 9B  illustrate the knot formation of  FIGS. 8A-8D  being used with an implant  900  that includes a cortical button  910 . The button  910  has at least two through holes  924   b ,  924   c  disposed therein and a suture filament  950  (e.g., a braided suture) associated with the button  910  to form the implant  900 . Similar to the suture  850 , the filament  950  can be formed into a pretzel shaped, or overhand, knot  952 . The knot  952  can be disposed on a top side  910   a  of the button  910 , and can have at least three collapsible openings  952   a ,  952   b , and  952   c . As shown, the first collapsible opening  952   a  can be located in a central location of the knot  952 , and the second and third collapsible openings  952   b ,  952   c  can be located on opposite sides from the first collapsible opening  952   a.    
     The knot  952  can have limbs  954 ,  955  extending therefrom that can be selectively passed through thru-holes  924   a - d  to associate the filament  950  with the button  910 . In the illustrated embodiment of  FIG. 9A , the first limb  954  passes distally through the third hole  924   c  to the bottom side  910   b  of the button  910 , and through the second hole  924   b  back to the top side  910   a  to form a first filament loop, or coil,  960   a . Similarly, the second limb  955  passes distally through the second hole  924   b  to the bottom side  910   b  of the button  910 , and through the third hole  924   c  back to the top side  910   a  to form a second filament loop  960   b.    
     When both the first and second limbs  954 ,  955  are on the top side  910   a  of the button  910 , they can then be passed through a first opening  952   a  of the overhand knot  952 . As shown, the first limb  954  is then passed distally through the fourth hole  924   d  to the bottom side  910   b  of the button  910 , and then through the first hole  924   a  back to the top side  910   a  to form a third coil  960   c . Likewise, the second limb  955  is passed distally through the first hole  924   a  to the bottom side  910   b  of the button  910 , and through the fourth hole  924   d  back to the top side  910   a  to form a fourth coil  960   d . The terminal end  954   t  of the first limb  954  can then be passed through the second collapsible opening  952   b , and the terminal end  955   t  of the second limb  955  can be passed through the third collapsible opening  952   c . As discussed above, the order and placement of the limbs  954 ,  955  through the openings  952   a ,  952   b , and  952   c , can be altered as desired without departing from the spirit of the present disclosure. 
     The knot  952  can be collapsed onto the suture limbs  954 ,  955  passing therethrough by application of a force F C  on the filament loops  960   a - 960   d , as shown in  FIG. 9A , while maintaining tension on the first and second limbs  954 ,  955 . A circumference of the first and third coils  960   a ,  960   c  can be adjusted by application of a pulling force F P  on the terminal end  954   t , and likewise, a circumference of the second and fourth coils  960   b ,  960   d  can be adjusted by application of the pulling force F P  on the terminal end  955   t  in manners similar to those described above. The inclusion of a second coil formed from each of the limbs  954 ,  955  increases the strength of the implant  900  due to a pulley effect, allowing the implant  900  to be more stable when it is implanted in bone and to more stably hold a ligament graft  970  attached through the filament loops  960   a - 960   d . Once the filament loops  960   a - 960   d  are collapsed to the desired lengths, the knot  952  is collapsed, the suture limbs  954 ,  955  can be tied with a half hitch knot proximate to the knot  952  to maintain a location of the knot  952  with respect to the button  910 , and then the suture limbs  954 ,  955  can be cut to length. The four loops  960   a - 960   d  can maintain a combined average maximum loading of at  least about  765  N  once implanted, with the strength being supplied, at least in part, by the knot configuration. 
     One advantage of passing the suture limbs  954 ,  955  through each opening of the overhand knot  952  is that each collapsible opening  952   a - 952   c  of the knot  952  is able to engage more surface area of the portion of the suture limbs  954 ,  955  passing therethrough. This additional surface area contact between the collapsible openings  952   a - 952   c  and the suture limbs  954 ,  955  creates a more secure cinch. Additionally, another advantage of passing the suture limbs  954 ,  955  through each opening of the overhand knot  952  is a reduction in binding of the knot  952  as compared to the suture limbs being threaded through a single opening of the knot. Still further, by including at least the four filament loops  960   a - 960   d , the load applied by the ligament implant  970  is better dispersed and therefore there is a reduction in cyclic displacement as compared to using only two filament loops. A further advantage is the resulting knot  952  can have a lower profile as compared to a knot where each limb is passed through a single opening of the knot. 
     Any number of filament loops can be formed from the first and second limbs  954 ,  955  to hold any number of ligament implants  970 , and the number of filament loops formed with the first limb  954  does not have to be the same as the number of filament loops formed by the second limb  955 . In some embodiments, three or four filament loops can be formed by one or both of the limbs  954 ,  955 . Further, the limbs used to form the filament loops can be passed through any number of thru-holes formed in the button  910 . The first limb  954  does not need to pass through the same collapsible opening through which the second limb  955  passes. Likewise, when multiple filament loops are formed with one limb, that limb does not have to be passed through the same thru-holes to form each coil. Moreover, the first limb  954  and the second limb  955  need not pass through the collapsible openings  952   a - c  in the order prescribed above. For example, the suture limbs  954 ,  955  can first pass through collapsible opening  952   b , then separately through collapsible openings  952   a  and  952   c . A person skilled in the art will recognize a number of configurations between the filament and thru-holes that can be used to form one or more coils in the filament limbs before disposing terminal ends of the limbs through the collapsible openings  952   a - c  of the knot  952  in any order. 
     One example of an alternate configuration is shown in the embodiment of  FIG. 10 . Similar to the implant  900 , a suture  950 ′ can be formed into a pretzel shaped, or overhand, knot  952 ′ disposed on a top side  910   a ′ of the body  910 ′. The knot  952 ′ can have three collapsible openings  952   a ′,  952   b ′, and  952   c ′. The suture configuration of the implant  900 ′ is similar to that of the implant  900  of  FIGS. 9A and 9B , however, instead of threading suture limbs through four of the openings in the cortical button, only two openings are used. In some embodiments, the body may only include two openings. As shown, limbs  954 ′,  955 ′ of the suture  950 ′ can extend from the knot  952 ′ and can be selectively passed through a first thru-hole  924   b ′ to a bottom side  910   b ′ then through a second hole  924   c ′ to associate the filament  950 ′ with the body  910 ′. In the illustrated embodiment of  FIG. 10 , the first limb  954 ′ passes distally through the second hole  924   b ′ to the bottom side  910   b ′ of the body  910 ′, and through the third hole  924   c ′ back to the top side  910   a ′ to form a first filament loop  960   a ′. Similarly, the second limb  955 ′ passes distally through the third hole  924   c ′ to the bottom side  910   b ′ of the body  910 ′, and through the third hole  924   c ′ back to the top side  910   a ′ to form a second filament loop  960   b′.    
     When both the first and second limbs  954 ′,  955 ′ are on the top side  910   a ′ of the button  910 ′, they can be passed through a first opening  952   a ′ of the overhand knot  952 ′. The first limb  954 ′ can then pass distally through the second hole  924   b ′ to the bottom side  910   b ′ of the body  910 ′, and through the third hole  924   c ′ back to the top side  910   a ′ to form a third filament loop  960   c ′. Likewise, the second limb  955 ′ can pass distally through the third hole  924   c ′ to the bottom side  910   b ′ of the body  910 ′, and through the second hole  924   b ′ back to the top side  910   a ′ to form a fourth filament loop  960   d ′. The terminal end  954   t ′ of the first limb  954 ′ can then be passed through the second collapsible opening  952   b ′, and the terminal end  955   t ′ of the second limb  955 ′ can be passed through the third collapsible opening  952   c ′. The knot  950 ′ can be collapsed onto the suture limbs  952 ′,  954 ′ passing therethrough by application of a force F c ′ on the filament loops  960   a ′- 960   d ′, while maintaining tension on the first and second limbs  954 ′,  955 ′. A circumference of the first and second coils  960   a ′,  960   c ′ can be adjusted by the terminal end  954   t ′ and the third and fourth coils  960   b ′,  960   d ′ can be adjusted by the terminal end  955   f  in manners similar to those described above. Further, any number of loops and any configurations with respect to the body  910  can be used. Still further, any combination of passing the limbs  954 ′,  955 ′ through the openings  952   a ′,  952   b ′,  952   c ′, as described above, can be used for this described embodiment without departing from the spirit of this disclosure. 
     The embodiment illustrated in  FIGS. 11A-11H  also include a cortical button  210  having at least three thru-holes  224   a ,  224   b ,  224   c  disposed therein and a suture filament  250  that is a braided suture associated with the button  210  to form an implant  300 . As shown in  FIG. 11A , a terminal end  254   t  of a first limb  254  is passed from a top side  210   a  to a bottom side  210   b  of the body  210  through one of the thru-holes  224   a  and a terminal end  255   t  of a second limb  255  is passed from the top side  210   a  to the bottom side  210   b  through another thru-hole  224   b . The two terminal ends  254   t ,  255   t  are then both passed back to the top side  210   a  through the third thru-hole  224   c , as shown in  FIG. 11B . The resulting configuration is a first loop  263  formed on the top side  210   a  from a central portion  250   c  of the filament  250  at an approximate midpoint  250   m  of the filament  250 , and first and second coils  260   a ,  260   b  primarily located below the bottom side  210   b.    
     As shown in  FIG. 11C , the terminal ends  254   t ,  255   t  can be formed into a sliding knot  252  such as a Buntline Hitch knot using techniques known to those skilled in the art. Other suitable sliding knots can be used in lieu of the Buntline Hitch knot. A force can then be applied in an approximate direction F to the terminal ends to tighten the Buntline Hitch knot, and as shown in  FIG. 11D , the stationary terminal end, as shown the terminal end  254   t , can be cut so that it is substantially shorter than the sliding terminal end extending proximally from the tightened sliding knot  252 , as shown the terminal end  255   t . The third thru-hole  224   c  can be sized such that the Buntline Hitch knot is too big to pass through it. Thus, a force in an approximate direction G can be applied to the longer sliding terminal end  255   t  to advance the knot  252  toward the body  210 , and to collapse the first loop  263  against the top surface  220  of the body  210 , as shown in  FIG. 11E . 
     Optionally, a secondary loop  280  can be added to the first and second coils  260   a ,  260   b , as shown in  FIG. 11F . As shown, the secondary loop  280  is a closed, fixed loop having an approximately fixed circumference. The secondary loop  280  can be formed using any number of techniques known to those skilled in the art, but in the illustrated embodiment the secondary loop is disposed around the first and second coils  260   a ,  260   b  and tied together to form the closed, fixed loop. As shown in  FIG. 11G , a ligament graft  302  can be disposed around the secondary loop  280 . While in other embodiments the ligament graft was only disposed around the loop once,  FIG. 11G  illustrates that ligament grafts  302  can be disposed around a filament in any of the embodiments described herein multiple times. A force in an approximate direction H can then be applied to the long remaining terminal end  255   t  to decrease the circumference of the first and second coils  260   a ,  260   b  and advance the ligament graft  302  closer to the body  210 , as shown in  FIG. 11H . 
     In the embodiment illustrated in  FIGS. 11A-11H , the ligament graft is not attached directly to coils  260   a ,  260   b  formed by the filament  250 , but instead is coupled to the secondary loop  280 . Such a secondary loop can be used in any of the embodiments described or derivable from disclosures made herein. In some embodiments the secondary loop can help minimize accidental graft damage due to wear with the main suture filament when the circumferences of the coils of the main filament are adjusted. 
     In some embodiments, including but not limited to those implants having a self-locking knot, a sleeve or spacer can be disposed over a portion of the first and second limbs on the top side of the body, adjacent to the top surface. The optional sleeve can assist in preventing a surgeon from cutting terminal ends of the limbs extending proximally from the knot too close to the body. The integrity of the knot, and thus the strength of the implant, can be compromised when the terminal ends of the limbs are cut too close to the body. The sleeve can generally have elastic properties such that it bunches as compressive forces are applied, and a surgeon can then cut the terminal ends at a location proximal of the sleeve. 
     As shown in  FIG. 12 , in one exemplary embodiment of an implant  400  formed by a body  310  and a suture filament  350  forming both a self-locking knot  352  on a top side  310   a  of the body  310  and a plurality of coils  360  substantially disposed on a bottom side  310   b  of the body  310 , sleeve  358  is a single suture filament having a plurality of bores formed therein to thread first and second limbs  354 ,  355  through the sleeve  358 . The sleeve  358  can be disposed around a portion of the first limb  354  on the top side  310   a , wrap around a bottom surface  322  of the body  310 , and then wrap back around to the top side  310   a  so it can be disposed around a portion of the second limb  355 . Wrapping the sleeve  358  around the bottom surface  322  can help minimize proximal movement of the sleeve  358 , toward the terminal ends  354   t ,  355   t  when the limbs  354 ,  355  are tightened. The first terminal end  354   t  passes into the sleeve  358  at a first bore  358   a  and out of the sleeve at a second bore  358   b , while the second terminal end  355   t  passes into the sleeve  358  at a third bore  358   c  and out of the sleeve at a fourth bore  358   d . As shown, free ends  358   e ,  358   f  of the sleeve  358  can extend proximally from the second and fourth bores  358   b ,  358   d.    
     In other embodiments, the free ends  358   e ,  358   f  can be eliminated, or the sleeve can be configured such that the free ends extend distally. The implant  100  of  FIG. 1B  is an example of an embodiment that does not include free ends. Rather, the first and second terminal ends pass into/out of the sleeve  58  at terminal ends  58   t   1 ,  58   t   2  of the sleeve rather than at first and fourth bores. In still other embodiments, separate sleeves can be disposed on each of the first and second limbs. In such embodiments, the only bores formed in the sleeves may be those formed at the respective terminal ends, and thus the first and second terminal ends of the filament can pass into and out of the sleeves through the terminal ends of the sleeves. In still further embodiments, the first and second terminal ends can extend through the same sleeve, or alternatively, free ends of the sleeve can be connected together to form a continuous loop. In addition to or in lieu of other sleeve configurations, other components configured to assist in allowing a surgeon to know where to cut the terminal ends after they are no longer needed can also be incorporated into the implants described herein without departing from the spirit of the disclosure. 
     The sleeve can be made from a wide variety of biocompatible flexible materials, including a flexible polymer, or it can be another filament. In one embodiment the sleeve is made of a polymeric material. In another embodiment, the sleeve is a flexible filament, such as a braided suture, for example Ethibond™ #5 filament. If the sleeve is formed from a high-strength suture such as Orthocord™ #2 filament, the braid can be relaxed by reducing the pick density. For example, Orthocord™ #2 filament, which is typically braided at sixty picks per 2.54 centimeters can be braided at approximately thirty to forty picks per 2.54 centimeters, more preferably at about 36 picks per 2.54 centimeters. If the sleeve material is formed about a core, preferably that core is removed to facilitate insertion of the filament limbs, which may themselves be formed of typical suture such as Orthocord™ #0 suture or #2 suture braided at sixty picks per 2.54 centimeters. 
     A length and diameter of the sleeve can depend, at least in part, on the size and configuration of the components of the construct with which it is used and the surgical procedure in which it is used. In embodiments in which the sleeve is a filament, a size of the sleeve can be in the range of about a #7 filament (about 18 gauge) to about a #2-0 filament (about 28 gauge), and in one embodiment the size can be about a #5 filament (about 20 gauge to about 21 gauge). In addition, the sleeve can be thickened by folding it upon itself coaxially, (i.e., sleeve in a sleeve). A person having skill in the art will recognize comparable diameters that can be used in instances in which the sleeve is made of a polymeric or other non-filament material. In embodiments in which a single sleeve is disposed over portions of both the first and second terminal ends, a length of the sleeve can be in the range of about 1 centimeter to about 12 centimeters, and in one embodiment the length can be about 5.5 centimeters. In embodiments in which separate sleeves are disposed over portions of the first and second terminal ends, a length of each sleeve can be in the range of about 0.5 centimeters to about 6 centimeters, and in one embodiment each has a length of about 2.5 centimeters. The axially compressible nature of the sleeves can be such that a length of the portion of the sleeve disposed on one of the limbs can compress fully to a length that is in the range of about one-half to about one-eighth the original length of that portion of the sleeve, and in one exemplary embodiment it can compress to a length that is about one-fifth the original length of that portion of the sleeve. Thus, if the length of the sleeve disposed around the first limb is approximately 3 centimeters, when fully compressed the sleeve can have a length that is approximately 0.6 centimeters. 
     In some embodiments, a second suture filament can be associated with the body of the implant to help guide or shuttle the filament during a surgical procedure. As shown in  FIG. 13 , an embodiment of an implant  500  includes a body  410  having two thru-holes  424  formed therein and a first surgical filament  450  coupled thereto. In the illustrated embodiment, rather than having a knot formed on a top side  410   a  of the body  410 , limbs  454 ,  455  of the first surgical filament  450  are intertwined around a mid-portion  450   m  of the filament  450  on the top side  410   a , thereby forming an intertwining configuration  452 . The first and second limbs  454 ,  455  can also extend distally from the intertwining configuration  452 . More particularly, the limbs  454 ,  455  can extend through the thru-holes  424  a plurality of times to form a plurality of coils  460   a ,  460   b  substantially disposed on a bottom side  410   b  of the body  410 . The friction resulting from the intertwining configuration  452  can be sufficient to assist in retaining sizes and positions of the coils  460   a ,  460   b , and to minimize any slipping associated therewith. 
     A second suture filament or shuttle filament  490  can be disposed longitudinally through the body as shown, for instance in a longitudinal bore  425  formed therethrough. The filament can extend substantially along a central, longitudinal axis L of the body  410 , and thus can extend through the thru-holes  424  formed in the body  410 , resulting in a leading end  490   a  and a trailing end  490   b . A knot  492  or other protrusion larger than a diameter of the longitudinal bore  425  can be formed in or otherwise located on the trailing end  490   b  and can assist the leading end  490   a  and the trailing end  490   b  in serving as a guide or shuttle for the implant  500 , as described in greater detail below with respect to  FIGS. 16A-16H . By using a single suture disposed through the longitudinal bore  425  to serve as a shuttle, the number of sutures used in the system can be reduced, thereby simplifying the procedure without diminishing the tactile feedback available to the surgeon once the body  410  has flipped on the femoral cortex. 
     Although the illustrated bore  425  extends through the body  410  and through each of the thru-holes  424 , a person skilled in the art will recognize other configurations that can be formed without departing from the spirit of the present disclosure, such as having the thru-holes  424  situated off-center of the body  410  so they are not intersected by the bore  425 , or the bore  425  having a path that does not necessarily extend through each thru-hole  424  or all the way through the body  424 . Additionally, in some embodiments the longitudinal bore  425  can be formed with an invagination (not shown) on a trailing end  418  of the body  410  such that it has a diameter that is approximately larger than the diameter of the bore  425  and approximately smaller than the diameter of the knot  492 . As a result, the knot  492  can be partially fit inside the body  410  and remain engaged with the body  410  even after the body has been flipped onto the femoral cortex. Once the body  410  is rotated through a specific angle, the knot  492  can disengage with the invagination and the filament  490  can easily be removed from the patient. A person having skill in the art will recognize that the size and depth of the invagination can control, at least in part, the release angle. 
     A person skilled in the art will recognize that one or more additional filaments, like the second filament  490 , can be associated with a variety of implant configurations, including configurations described herein or derivable therefrom. Two further non-limiting examples of implants having second suture filaments for shuttling are illustrated in  FIGS. 11A and 11B and 12A and 12B . 
     The implant  600  of  FIGS. 14A and 14B  includes a body  510  having two thru-holes  524  formed therein and a first surgical filament  550  coupled thereto. The surgical filament  550  is similar to the surgical filament  50  of  FIG. 5  in that limbs  554 ,  555  of the filament  550  are used to form a self-locking knot  552  disposed on a top side  510   a  of the body  510  and four coils  560   a ,  560   b ,  560   c , and  560   d  that pass through the thru-holes  524  and are substantially disposed on a bottom side  510   b  of the body  510 . First and second terminal ends  554   t ,  555   t  of the limbs  554 ,  555  can extend proximally from the self-locking knot  552  and can be used at least to adjust sizes of the coils  560   a ,  560   b ,  560   c , and  560   d  in manners consistent with descriptions contained herein. A second suture filament or shuttle filament  590  can be disposed longitudinally through a longitudinal bore  525  formed in the body  510  along a central, longitudinal axis M, and thus can extend through the thru-holes  524  formed in the body  510 . Similar to the implant  500  of  FIG. 13 , a knot  592  larger than a diameter of the longitudinal bore  525  can be formed in a trailing end  590   b  of the second filament  590  and can assist a leading end  590   a  and the trailing end  590   b  in serving as a guide or shuttle for the implant  600 . 
     The implant  700  of  FIGS. 15A and 15B  includes a body  610  having four thru-holes  624  formed therein and a first surgical filament  650  coupled thereto. As shown, the four thru-holes  624  include two inner thru-holes  624   b  and  624   c  that can be used to receive the filament  650  and two outer thru-holes  624   a  and  624   d  that can be used to receive shuttle filaments. As shown, the outer thru-holes  624   a ,  624   d  can be disposed closer to leading and trailing ends  616  and  618 , respectively, than to the inner thru-holes  624   b  and  624   c , and thus the four thru-holes  624  are not approximately equally spaced apart with respect to each other. As also shown, diameters of the two inner holes  624   b  and  624   c  are larger than diameters of the two outer holes  624   a  and  624   d . The surgical filament  650  is similar to the surgical filament  50  of  FIG. 5  in that first and second limbs  654 ,  655  of the filament  650  are used to form a self-locking knot  652  disposed on a top side  610   a  of the body  610  and four coils  660   a ,  660   b ,  660   c , and  660   d  that pass through the thru-holes  624   b ,  624   c  and are substantially disposed on a bottom side  610   b  of the body  610 . First and second terminal ends  654   t ,  655   t  of the limbs  654 ,  655  can extend proximally from the self-locking knot  652  and can be used at least to adjust sizes of the coils  660   a ,  660   b ,  660   c , and  660   d  in manners consistent with descriptions contained herein. As shown, a second, leading suture filament or leading shuttle filament  690  can be disposed through the outer thru-hole  624   d  and around the leading end  616 , and a third, trailing shuttle filament  691  can be disposed through the outer thru-hole  624   a  and around the trailing end  618 . As described below with respect to aspects of  FIGS. 16A-16H , the shuttle filaments  690  and  691  can serve as a guide or shuttle for the implant  700  to assist in passing the implant  700  through a bone tunnel. 
     Similar to other filaments of the present disclosure, a shuttle filament can be an elongate filament of a variety of types, including but not limited to a cannulated filament, a braided filament, and a mono filament. The type, size, and strength of the filament can depend, at least in part, on the other materials of the implant, such as the cortical button, and the type of procedure in which it is used. In one exemplary embodiment the second suture filament is formed from a #5 filament (about 20 gauge to about 21 gauge). In some embodiments the filament can have a size in the range of about a #2-0 filament (about 28 gauge) and about a #5 filament (about 20 gauge to about 21 gauge). A length of the filament can be in the range of about 0.1 meters to about 1.5 meters, and in one embodiment the length is about 1 meter. 
     Different exemplary features associated with performing an ACL repair using a surgical implant like those described herein are illustrated in  FIGS. 16A-16H . The implant  800  illustrated in  FIGS. 16A and 16D -G generally includes thru-holes  724  (not shown) formed therein and a first surgical filament  750  coupled thereto. As shown, first and second limbs  754 ,  755  ( FIGS. 16F and 16G ) of the first surgical filament  750  can be used to form a self-locking knot  752  disposed on a top side  710   a  of the body  710  and a plurality of coils—as shown two coils  760   a ,  760   b , but any number of coils can be formed in accordance with the teachings herein—that pass through the thru-holes  724  and are substantially disposed on a bottom side  710   b  of the body. Extending proximally from the knot can be first and second terminal ends  754   t ,  755   t  of the limbs  754 ,  755 , which can be used at least to adjust sizes of the coils  760   a ,  760   b  in manners consistent with descriptions contained herein. One or more additional filaments can be associated with the leading and/or trailing ends  716 ,  718  of the body  710 . As shown, a second filament  790  is associated with the leading end  716 , and a third filament  791  is associated with the trailing end  716 . A graft  802  can be associated with the coils  760   a ,  760   b  using techniques known to those skilled in the art. 
     A surgeon can begin the procedure by preparing the knee  1000  and soft tissue tendon grafts using techniques known by those skilled in the art. As shown in  FIG. 16A , a bone tunnel  1002  can be formed in a femur  1001  and tibia  1003 , with a femoral tunnel  1004  of the bone tunnel  1002  including a main channel  1005  and a passing channel  1007 , the passing channel  1007  having a smaller diameter than the main channel  1005 , and the femoral tunnel  1004  being in direct communication with a tibial tunnel  1006  disposed in the tibia  1003 . The implant  800  can be introduced into the tibial tunnel  1006  by applying a force in an approximate direction J to the second and third suture filaments  790 ,  791 , which both extend toward the femoral tunnel as shown. The terminal ends  754   t ,  755   t  can also extend toward the femoral tunnel, such that six strands of suture all extend out of the femoral tunnel  1004 , proximal of the bone tunnel  1002 . 
       FIGS. 16B and 16C  illustrate example orientations for implants  700  and  600  of  FIGS. 15A and 15B  and  FIGS. 14A and 14B , respectively, if they were to be inserted into the bone tunnel  1002  in a manner similar to the implant  800 . As illustrated in  FIG. 16B , all six terminal ends of the filaments  650 ,  690 , and  691  associated with the body  610  can extend proximally when inserted through the bone tunnel  1002  (not shown). These terminal ends include the first and second terminal ends  654   t ,  655   t  of the first filament  650 , first and second terminal ends  689   t ,  690   t  of the leading shuttle filament  690 , and first and second terminal ends  691   t ,  692   t  of the trailing shuttle filament  692 . Similarly, as illustrated in  FIG. 16C , all four terminal ends of the filaments  550  and  590  associated with the body  510  can extend proximally through the bone tunnel  1002  (not shown). These terminal ends include the first and second terminal ends  554   t ,  555   t  of the first filament  550  and first and second terminal ends  589   t ,  590   t  of the shuttle filament  590 . Grafts  702 ,  602  can be associated with coils  660 ,  550  of the implants  700 ,  600  using techniques known to those skilled in the art. Further, a person skilled in the art will recognize that as the implants  700 ,  600  are inserted into the bone tunnel, filaments and grafts located on the top and bottom sides  610   a ,  510   a  and  610   b ,  510   b , respectively, can be flexible to allow the construct to be disposed in the tunnel, similar to the implant  800  of  FIG. 16A . 
     Turning back to the implant  800 , as shown in  FIG. 16D , a force in the approximate direction J can be applied to terminal ends  790   t ,  791   t  of the second and third filaments  790 ,  791 , as well as to the terminal ends  754   t ,  755   t  of the first and second limbs  754 ,  755 , to advance each through the tibial tunnel  1006  and into the femoral tunnel  1004 . A counterforce can be applied to the graft  802  so that the entire construct is not fully inserted into the bone tunnel  1002 , as in exemplary embodiments the graft  802  can be used to help orient the cortical button  710  with respect to the bone tunnel  1002 . Further, as the body  710  and coils  760   a ,  760   b  enter the bone tunnel  1002 , care can be taken to prevent the body  710  from becoming wrapped in the coils  760   a ,  760   b . Once the implant  800  enters the bone tunnel  1002 , scopes can be used to continue to monitor it. If the coils  760   a ,  760   b  undesirably wrap around the body  710 , the surgeon can use instruments to unwrap the coils  760   a ,  760   b  from the body  710  and/or the surgeon can selectively apply tension to the second and third suture filaments  790 ,  791  and the graft  802  to manipulate the cortical button  710 . 
     Continued application of the force in the approximate direction J can pull the body  710  through the passing channel  1007 . As the body  710  passes through the passing channel  1007  and crests while passing out of the channel, i.e., when a substantial portion of the body is disposed outside of the channel, as shown in  FIG. 16E , the surgeon can prepare to orient or manipulate the body so that it flips or changes orientation. Because tissue and ligaments can be located near the proximal end of the femoral tunnel  1004 , typically when cortical buttons pass out of a femoral tunnel, the extra tissue can make it difficult to direct the button to a desired location. However, the second and third filaments  790 ,  791  can assist in manipulating the button  710  to a desired location in which the flat bottom surface  720  rests on the femoral cortex and faces the femoral tunnel  1004 , as shown in  FIG. 16F . This allows the coils  760   a ,  760   b  and graft  802  associated therewith to be disposed in the bone tunnel  1002  and the knot  752  to be located outside of but adjacent to the bone tunnel  1002 . 
     A variety of techniques can be used to flip or reorient the button, but in the illustrated embodiment, shown in  FIG. 16F , a force in an approximate direction K is applied to the graft  802 , thus tensioning the graft and causing the button  710  to flip. In other embodiments, a surgeon can selectively apply tension to the graft  802  and the second and third filaments  790 ,  791  to flip the button  710  to its desired location. Once the surgeon has oriented the button  710  as desired, the surgeon can confirm its location as lying flat on the femoral cortex, directly adjacent to the femoral tunnel  1004 , using a variety of techniques, including by using tactile feedback received from pulling the second and third filaments  790 ,  791  and the graft  802 , and/or using visual aids. 
     Once the body  710  is disposed at its desired location, tension can be applied to the terminal ends  754   t ,  755   t  of the limbs  754 ,  755  to adjust the circumference of the coils  760   a ,  760   b , thereby moving the graft  802  within the bone tunnel  1002  to a desired location. The circumferences of the coils  760   a ,  760   b  can be adjusted using a number of different techniques, including those described herein. In one exemplary embodiment, illustrated in  FIG. 16G , the first and second terminal ends  754   t ,  755   t  can be selectively pulled in an approximate direction N to advance the graft  802  through the tunnel  1002 . 
     Once the implant  800  and graft  802  are positioned in their desired locations, excess filaments can be removed, including portions of the terminal ends  754   t ,  755   t  and the second and third filaments  790 ,  791 . In some embodiments the second and third filaments can be completely removed, while care can be taken to ensure that enough material remains with respect to the terminal ends  754   t ,  755   t  so as not to negatively impact the integrity of the knot  752 . Then the remaining portions of the repair can be carried out, such as steps related to tibial fixation 
       FIG. 16H  illustrates an embodiment of an ACL repair method in which a filament  750 ′ is used to form four coils  760   a ′,  760   b ′,  760   c ′,  760   d ′, two ( 760   a ′,  760   c ′) of which are associated with a first graft  802 ′ and two ( 760   b ′,  760   d ′) of which are associated with a second graft  804 ′. As shown in  FIG. 16H , the cortical button  710 ′ is already oriented or flipped so that the top surface  720 ′ rests on the femoral cortex and faces the femoral tunnel  1004 , for instance relying on techniques disclosed herein, and thus circumferences of the coils  760   a ′,  760   b ′,  760   c ′,  760   d ′ can be adjusted to selectively locate them within the bone tunnel  1002 . These techniques include, for instance, those discussed above with respect to  FIGS. 6A and 6B . In one exemplary embodiment, tension can be alternately applied in an approximate direction P to first and second terminal ends  754   t ′,  755   t ′ to advance the grafts  802 ′,  804 ′ in increments of approximately 1 centimeter. Alternatively, the grafts  802 ′,  804 ′ can be advanced by using a configuration in which the first and second terminal ends  754   t ′,  755   t ′ are tied together and held in one hand while tension in the approximate direction Q is applied to the grafts  802 ′,  804 ′ by another hand. The surgeon can then alternate between pronation and supination to tighten the filament limbs, and thereby the coils  760   a ′,  760   b ′,  760   c ′,  760   d ′, which in turn advances the grafts  802 ′,  804 ′ proximally through the bone tunnel  1002 . 
     The grafts  802 ′,  804 ′ can be advanced to a desired location, for example up to the passing channel  1007  of the femoral tunnel  1004 . When a graft  802 ′,  804 ′ reaches the passing channel  1007 , typically the resistance to tightening of the coils  760   a ′,  760   b ′,  760   c ′,  760   d ′ noticeably increases. In some embodiments, such as that illustrated in  FIG. 16H , one or more loops  760   a ′,  760   c ′ can have a smaller circumference than other loops  760   b ′,  760   d ′ so that one graft  802 ′ is more proximally located than the other graft  804 ′. As also illustrated in  FIG. 16H , any shuttle filaments used in the method can be removed, and the terminal ends  754   t ′,  755   t ′ can be shortened as described herein. 
     A person skilled in the art will also recognize how other embodiments described herein or derivable therefrom can be easily adapted for use with the procedures described herein, and in some instances can provide additional benefits. By way of non-limiting example, for embodiments such as those illustrated in  FIGS. 14A, 14B, and 16C  in which a single filament is used for purposes of shuttling the body, removal of the filament after placement of the cortical button can be easier than if separate filaments are tied to respective leading and trailing ends of the button. 
     The ability to control two independently tensioned ligament grafts in a single tunnel using a single cortical button is an improvement over existing techniques for ACL repairs. In existing methods for performing ACL repairs, a cortical button having filament associated therewith can only control a single bundle of ligament graft. Thus, if independent movement of multiple ligaments is needed, each ligament is typically associated with its own cortical button. Some surgeons use a double-tunnel technique to implant two ligaments, thus fixing each graft bundle in separate tunnels. Double-tunnel techniques likewise require one button per bundle. Thus, the methods described and resulting from disclosures herein represent improved ACL repair techniques because they allow for two ligament bundles to be independently moved using a single button, and doing so in a single tunnel. This results in procedures that have a reduced risk of complications and is generally less complex than existing procedures. A person skilled in the art will recognize that the disclosures pertaining to independently controlling two filament loops can be broadly applied to a variety of implant designs and surgical procedures, and can even be applied to non-medical fields without departing from the spirit of the present disclosure. 
     One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. By way of non-limiting example, the exemplary ACL repair methods described herein with respect to  FIGS. 16A-16H  can be adapted for use with the other implant configurations described herein or derivable from the disclosures herein. All publications and references cited herein are expressly incorporated herein by reference in their entirety.