Patent Publication Number: US-2021186483-A1

Title: Graft suspension device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/460,205 filed on Jul. 2, 2019, which is a continuation of U.S. patent application Ser. No. 15/431,927 filed on Feb. 14, 2017, which claims priority to and benefit of U.S. Provisional Application No. 62/295,791, filed on Feb. 16, 2016, the contents of which are incorporated by reference herein in their entirety for all purposes. 
    
    
     FIELD 
     The present disclosure relates to a graft suspension device and, in particular, a graft suspension device for graft fixation such as tendon or ligament fixation. 
     BACKGROUND OF THE DISCLOSURE 
     Sports injuries are increasingly common, such as when tissues such as ligaments or tendons tear or detach from bone. Surgical techniques have been developed to reconstruct such soft tissues and to re-attach them to the relevant bone. One of the most common types of such injuries is the tearing of the anterior cruciate ligament (ACL) in the knee. The ACL connects the femur to the tibia at the center of the knee joint. Reconstruction of such tissues generally involves replacement with a graft, such as autologous or artificial tendon. 
     One method of graft fixation within the femoral tunnel involves the use of a fixation device on the anterolateral femoral cortex which is attached to the graft by means of sutures or tapes. The ligament anchor may be threaded through a femoral tunnel formed through the femur from the center of the knee. Sutures are attached directly to the fixation device on the outside of the femur above the knee the graft is looped through the suture before passing out of the femoral tunnel and being secured to the tibia. 
     One particularly important issue in the grafting operation is the formation of the suture loop attached to the fixation device, over which the graft is passed. Rigid suture loops require that the end surgeon have an inventory of multiple sizes of rigid loops depending on the size of the bone tunnel. Rigid loops also require an extra 3-5 mm of tunnel depth in order to maneuver the fixation device during the surgical procedure. Adjustable loops, on the other hand, require movement of the suture loop around the fixation device, causing abrasion to the attached graft. Concerns about adjustable loops inadvertently lengthening after graft fixation also exist. 
     SUMMARY OF THE DISCLOSURE 
     Described herein is a graft suspension device for a ligament fixation graft comprising an anchor or cortical button at one end, a ligament cradle at the other end and an adjustable length of suture therebetween, the suture formed into at least two loops engaging the anchor. A cradle at the midpoint of the suture comprises a sleeve portion through which the ends of the suture are threaded in opposite directions to cross-over in the sleeve portion and emerge at opposite ends of the sleeve portion. The ends of the suture are then routed through apertures in the anchor separate from the routing of the suture loops. Finally, the two ends of the suture are joined together to form a single tail. The size of the loops may be changed as the single tail is manipulated. However, the cradle stays centered on the suture even while the size of the loops change. This lack of cradle movement advantageously eliminates relative motion of the suture to the graft, which may weaken or cut the graft. The single tail, moreover, allows a surgeon to reduce the size of the loop with one hand. 
     Further examples of the graft suspension device of this disclosure may include one or more of the following, in any suitable combination. 
     In one example, the graft suspension device includes a suspension means for suspending a ligament in a bone hole. The suspension means includes an anchoring means at one end. The anchoring means has an anchor having a proximal end, a distal end, and a longitudinal axis extending between the proximal and distal ends. The anchor further has an outer pair, an intermediate pair and two central pairs of apertures configured for passage of a suture. The outer pair and the intermediate pair of apertures are aligned along the longitudinal axis, and the two central pairs of apertures are offset from the longitudinal axis but aligned with each other transverse to the longitudinal axis. The suspension means also includes a cradling means at the opposite end from the anchoring means, and an adjustable length of suture between the anchoring means and the cradling means. The suture is formed into at least two loops engaging the two central pairs of apertures of the anchor. The cradling means includes a sleeve portion though which first and second ends of at least a first of the at least two loops are threaded in opposite directions to cross over in the sleeve portion and emerge at opposite ends of the sleeve portion. The first and second ends of the suture are then passed through separate ones of the intermediate pair of apertures and joined together to form a single tail. Manipulation of the single tail changes the size of the at least two loops. The sleeve portion remains centered with respect to the anchor when the size of the at least two loops is reduced. 
     In further examples, the single tail is formed from the first end of the suture being spliced within the second end of the suture, and the second end of the suture being spliced within the first end of the suture. The single tail is adapted to include a gripping element. The suture is formed from a plurality of threads, the threads being plaited together to form a hollow tubular structure. A length of the adjustable length of suture is about 46 inches. A length of the anchor is about 10 mm to about 15 mm and a width of the anchor is about 2 mm to about 5 mm. The graft suspension device further includes at least one ligament graft engaged with the cradling means. The sleeve portion forms an integral part of a second of the at least two loops. The sleeve portion includes first and second openings formed in a second of the at least two loops at spaced intervals through which the first and second ends of the suture are threaded. A length of the sleeve portion is selected to be long enough accommodate a ligament fixation graft suspended thereover, but short enough to facilitate adjustment of at least one of the at least two loops. A diameter of the intermediate pair of apertures is selected to be larger than a diameter of the outer and inner pairs of apertures. 
     An example of the method of forming a graft suspension device includes threading first and second ends of a suture through respective first apertures of a central pair of apertures from an underside to a top side of an anchor, the suture forming at least two loops; threading the first and second ends of the suture through respective second apertures of the central pair of apertures from the top side to the underside of the anchor; threading the first and second ends in opposite directions through a sleeve portion formed in a cradle of the suture; threading the first and second ends of the suture through respective first and second apertures of an intermediate pair of apertures from an underside to the top side of the anchor; and joining the first and second ends of the suture together to form a single tail. The single tail is adapted to include a gripping element. When the single tail is pulled away from the anchor in an opposite direction from the cradle, a length of at least one of the at least two loops is shortened. As a length of the at least one of the at least two loops is shortened, the cradle remains centered with respect to the anchor. Joining the first and second ends of the suture together includes splicing the first end of the suture within the second end of the suture, and splicing the second end of the suture within the first end of the suture. Release of the single tail after the length of the at least one of the at least two loops is shortened does not cause the at least one of the at least two loops to re-lengthen. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the disclosure will now be described by way of example, with reference to the accompanying drawings in which: 
         FIG. 1A  shows a graft suspension device in accordance with the present disclosure; 
         FIG. 1B  shows a detail of the anchor of  FIG. 1A ; 
         FIG. 1C  is a schematic of the method of forming the suspension loop of  FIG. 1A ; 
         FIG. 2A  shows a graft suspended over the cradle portion of a suspension loop in accordance with the present disclosure; 
         FIGS. 2B and 2C  demonstrate a shortening of the suspension loop of  FIG. 1A ; 
         FIGS. 3A-D  show a method of splicing the suture ends in accordance with the present disclosure; and 
         FIGS. 4A-C  show a method of forming a finger loop in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The foregoing and other features will be apparent from the following description of particular embodiments disclosed herein, as illustrated in the accompanying drawings. 
     In the description that follows, like components have been given the same reference numerals, regardless of whether they are shown in different examples. To illustrate an example(s) of the present invention in a clear and concise manner, the drawings may not necessarily be to scale and certain features may be shown in somewhat schematic form. Features that are described and/or illustrated with respect to one example may be used in the same way or in a similar way in one or more other examples and/or in combination with or instead of the features of the other examples. 
     Comprise, include, and/or plural forms of each are open ended and include the listed parts and can include additional parts that are not listed. And/or is open ended and includes one or more of the listed parts and combinations of the listed parts. 
     Referring now to  FIG. 1A , an example of the graft suspension device  10  of this disclosure is shown. The graft suspension device  10  comprises a strand of suture  22  having a first loop  12  and a second loop  14  (together, the suspension loop  24 ) suspended from an anchor  16 . The suture  22  is formed from a braided material having plaited threads which together form a hollow tubular material. The suture  22  may be made from a suitable bio-compatible material which may be a bio-absorbable material or a non-absorbable permanent material. A length of the strand of suture  22  may be about 46 inches. The anchor  16  may be of conventional construction for securement to the outside of a bone, such as a cortical button. A length of the anchor (or cortical button)  16  may be about 10 mm to about 15 mm and a width may be about 2 mm to about 5 mm. The graft suspension device  10  also has a cradle  20  located substantially midway along the length of the suture  22 , as further described below. The cradle  20  includes a sleeve portion  18  at the opposite end of the suspension loop  24  to the anchor  16 , as further described below. 
     As further shown in  FIG. 1A , the anchor  16  includes a plurality of apertures, which may be eight apertures, extending therethrough and configured for the passage of the suture  22  (see, also,  FIG. 1B ). Outer and intermediate apertures  1 ,  2 ,  7  and  8  are aligned with each other along the longitudinal axis of the anchor  16 . Central apertures  3 ,  4 ,  5  and  6  are formed in two pairs symmetrically offset from the longitudinal axis but aligned with each other transverse to the longitudinal axis. The two pairs of central apertures  3 ,  4 ,  5 ,  6  are designed to accommodate the suture loops  12 ,  14  therethrough. The intermediate pair of apertures  2 ,  7  are designed to accommodate the two ends  30 ,  32  of the suture respectively. The outer pair of apertures  1 ,  8  are designed to assist in the placement of the anchor  16  on the outside of a bone through the use of leading and trailing sutures passed through apertures  1 ,  8  (not shown). A diameter of the intermediate pair of apertures  2 ,  7  may be selected to be larger than a diameter of the apertures  1 ,  3 ,  4 ,  5 ,  6 , and  8 . First and second loops  12 ,  14  are shown threaded through the central apertures  3 ,  4 ,  5 ,  6  as further described below. The loose ends  30 ,  32  of the suture  22  are shown threaded through the sleeve portion  18  to complete the suspension loop  24 . The threading of the loose ends  30 ,  32  in this manner has the effect of widening the sleeve portion  18  with respect to the remainder of the suspension loop  24 . The loose ends  30 ,  32  are then shown as passing through the intermediate pair of apertures  2 ,  7  and joined together to form a single tail  34 , as further described below. Advantageously, routing the suture  22  through the plurality of apertures keeps the various strands of suture  22  separated, making them less likely to bunch or tangle. The single tail  34  may be further adapted to form a finger loop  36  to provide a means whereby the surgeon can adjust the distance of the cradle  18  from the anchor  16 , and/or shortening the length of the suspension loop  24 , either before or during the surgical operation. Advantageously, the finger loop  36  may be used with just one hand. 
     As shown in  FIG. 1C , the sleeve portion  18  forms an integral part of the first and second loop  12 ,  14 . First and second eyes  38 ,  40  are formed in the sleeve portion  18  at spaced intervals through which the loose ends  30 ,  32  may be threaded, as further described below. It is contemplated by this disclosure that first and second eyes  38 ,  40  need not be formed in the sleeve portion  18  if the loose ends  30 ,  32  may be threaded therethrough by passing through gaps between adjacent threads of the braided suture  22 . A length of the sleeve portion  18  can vary, but is selected to be sufficiently long enough to accommodate a ligament fixation graft suspended thereover, but short enough to facilitate efficient adjustment of the suspension loop  24 . 
     Still referring to  FIG. 1C , forming the first and second loops  12 ,  14  involves threading the loose ends  30 ,  32  through a respective pair of central apertures  3 ,  4 ,  5 ,  6  of the anchor  16  from the underside to the top side thereof. More particularly, loose end portion  30   a  is threaded through central aperture  4  and loose end portion  32   a  is threaded through central aperture  5 . Each of the loose end portions  30   a ,  32   a  are then looped back through the other of the pair of apertures  6 ,  3  adjacent to the aperture through which it has already been passed. Specifically, the loose end portion  32   b  passes through aperture  3  from the top side to the underside of the anchor  16 , and loose end portion  30   b  passes through aperture  6  from the top side to the underside of the anchor  16 . Thereafter, loose end portion  30   b  is threaded through cradle portion  18  entering aperture  40  and exiting aperture  38 . Likewise, loose end portion  32   b  is threaded through the cradle  18  in the opposite direction, entering aperture  38  and exiting aperture  40 . At this stage, each loose end portion  30   c ,  32   c  is passed through the intermediate pair of apertures  2 ,  7 , from the underside of the anchor to the top side thereof, i.e., loose end portion  30   c  is passed through aperture  2  and loose end portion  32   c  is passed through aperture  7 . The loose end portions  30   c ,  32   c  are then joined together to form the single tail  34  ( FIG. 1A ) on the side of the anchor opposite from the cradle. 
     In  FIG. 2A , a pair of ligament grafts  42 ,  44  are shown looped over the cradle  20  midway along the length thereof. Examples of grafts for use in the disclosure include ligament or tendon, in particular, reconstructed ligament or tendon. Advantageously, the wider sleeve portion  18  prevents the suture  22  from cutting into the grafts  42 ,  44  during the grafting process. Additionally, by pulling on the single tail  34  ( FIG. 1 ) to shorten the length of the suspension loop  24 , the cradle  20  remains centered with respect to the anchor  16 , thus further preventing abrasion of the grafts  42 ,  44 . For example, as shown in  FIGS. 2B and 2C , the suspension loop  24  may be shortened from about 100 mm to about 8-10 mm (or to lengths therebetween) without the cradle  20  moving from a centered position with respect to the anchor  16 . 
       FIGS. 3A-D  detail a method of joining loose ends  30 ,  32  together to form the single tail  34 .  FIG. 3A  shows the loose ends  30 ,  32  passed through apertures  2 ,  7  on the opposite side of the anchor  16  from the cradle  20  (not shown). As shown in  FIG. 3A , loose end  32  is captured through loose end  30  by means of a snaring tool  46  or other suitable tool. A shown in  FIG. 3B , loose end  30  is subsequently snared through loose end  32 . Advantageously, this reciprocity in splicing provides that, when the single tail  34  is pulled, loose ends  30 ,  32  do not slip relative to each other. This prevents the cradle  20  from moving from a centered position with respect to the anchor  16 . It is also contemplated by this disclosure that the loose ends  30 ,  32  may be joined together to form a single tail  34  by other means, as long as loose ends  30 ,  32  do not slip relative to each other when the single tail  34  is pulled. 
     As shown in  FIG. 3C , optionally, loose end  32  may be further ensnared inside a lumen of loose end  30 . As shown in  FIG. 3D , loose end  32  is pulled inside loose end  30 , and is then trimmed flush to the spliced portion  48 . In this way, the spliced loose ends  30 ,  32  form the entire length of the spliced portion  48 , for greater pulling strength. The length of the single tail  34  is selected to be of sufficient length to pass out through an entrance of a bone tunnel to allow the surgeon to tension the grafts  42 ,  44  ( FIG. 2A ) or to simply adjust the length of the suspension loop  24  by pulling on the single tail  34 . This allows for ease of tensioning and loop length adjustment both pre-operatively and/or intra-operatively. 
       FIGS. 4A-C  show a method for forming finger loop  36 . To form the finger loop  36 , the suture snare  46  is placed through remaining loose end  30  at two locations. The loose end  30  is then pulled through itself. The snaring tool  46  is then placed inside the lumen of loose end  30  and the loose end  30  is pulled inside to create the finger loop  36 . By moving the finger loop  36  away from the cradle portion  18 , the length of the suspension loop  24  is shortened and, in this manner, the tensioning of the grafts,  42 ,  44  ( FIG. 2A ) may take place. Advantageously, release of the finger loop  36  after shortening does not cause the suspension loop  24  to re-lengthen. Therefore, the surgeon can adjust the grafts,  42 ,  44  to the required tension and then tie-off subsequently, without the tension of the grafts,  42 ,  44  being significantly lost in the intervening period. 
     While the system, apparatus and methods defined herein have been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.