Abstract:
A method and device for knotless fixation of tissue. A swivel anchor having a rotatable implant is used to capture suture for surgical tissue repair without requiring suture knots. The implant may be provided with a conical metal tip which is self-punching and avoids the need for pre-drilling a hole in bone. The implant includes a closed aperture to allow free sliding of a suture strand. The swivel anchor is secured in a hole in bone by advancing a fixation device, such as a cannulated interference screw, over the body of the implant.

Description:
This application is a continuation of U.S. application Ser. No. 12/043,008, filed on Mar. 5, 2008, now abandoned, which is a continuation-in-part of U.S. application Ser. No. 11/802,057, filed on May 18, 2007, which claims the benefit of U.S. Provisional Application Ser. No. 60/801,097, filed on May 18, 2006, the entire disclosures of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to methods and instruments for fixation of sutures and tissue to bone. 
     BACKGROUND OF THE INVENTION 
     When soft tissue tears away from bone, reattachment becomes necessary. Various devices, including sutures, screws, staples, wedges, anchors and plugs have been used in the prior art to secure soft tissue to bone. Surgical methods utilizing suture anchors alone are disadvantageous for reattachment of large areas of detached tissue because they often do not allow good tissue to bone contact. 
     Reattachment of soft tissue to bone typically requires the surgeon to pass suture material through selected tissue, form a plurality of surgical knots extracorporeally and then move the knots into position adjacent the desired tissue to be sutured. In such procedures, the surgeon must manually tie the knots on the suture strands after the suture is threaded through the selected tissues to be sutured. Knot tying during surgery, particularly arthroscopic surgery, is tedious and time-consuming. There is also a tendency for the knots to deform or collapse as the surgeon manually forces the knots down into the proper position. Also, the suture knots often are exposed to abrasion or cutting by sharp or rough areas along the walls of the bone canal into which anchors are typically inserted to provide fixation of tendon to bone. 
     Accordingly, a need exists for an improved method for attaching soft tissue to bone which does not require multiple suture knots and which allows the tendon to remain securely in place until the ligaments naturally attach to bone. 
     SUMMARY OF THE INVENTION 
     The instruments and methods of the present invention overcome the disadvantages of the prior art, such as those noted above, by providing a swivel implant at the distal end of a driver that securely engages and locks into a cannulated ribbed body of an interference plug or screw. The swivel implant includes a closed aperture for receiving a strand attached to a graft, such that the strand is able to freely slide through the aperture. 
     In one embodiment of the invention, the strand is passed through the graft at desired points. A cannulated plug or screw is pre-loaded onto a driver provided with a swivel lock twist-in anchor at its distal end. The strand attached to the graft is passed through the aperture of the swivel implant located at the distal end of the driver. The distal end of the driver together with the implant is inserted directly into the bone. The driver may be rotated (in a clockwise direction, for example) to advance a screw over the anchor to complete insertion. 
     Other features and advantages of the present invention will become apparent from the following description of exemplary embodiments of the invention described with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-6  depict a series of steps of shoulder repair using a plurality of swivel anchor devices according to the present invention. 
         FIG. 7  illustrates various views of the driver assembly of the present invention. 
         FIGS. 8 and 9  illustrate the swivel implant and traction suture. 
         FIG. 10  is an enlarged view of the fixation device (cannulated screw) used in the present invention. 
         FIG. 11  illustrates various views of a swivel anchor with a metal tip which avoids the need to pre-drill a hole in bone. 
         FIGS. 12 and 13  provide additional illustrations of the swivel anchor assembly of the present invention, and the swivel anchor inserted in a bone socket, respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides apparatus and methods for knotless tissue fixation using a swivel anchor device. 
       FIG. 1  illustrates a side view of a human shoulder of a patient undergoing a rotator cuff repair in accordance with an exemplary embodiment of the present invention. The patient may be positioned in the beach chair position using the Arthrex Beach Chair Lateral Traction Device or in a lateral decubitus position using the Arthrex 3-Point Shoulder Distraction System. Access to the subacromial space is facilitated with a variety of cannulas. 
     First, and as illustrated in  FIG. 1 , the mobility of the tear is assessed using, for example, a tissue grasper  10  such as the Arthrex KingFisher™ Suture Retriever/Tissue Grasper, to determine whether a U or L-shaped component exists. Where large tears extend to the superior aspect of the glenoid, margin convergence suturing is performed to reduce volume and strain on the repair. Subsequently, the length and width of the rotator cuff footprint is assessed and a bleeding bed for enhanced tendon to bone healing may be formed. This may be accomplished with a burr to perform a light dusting of the greater tuberosity, or by using a chondro pick to microfracture the footprint and maximize vascular channels. 
       FIG. 2  illustrates the preparation of two pilot holes for two swivel anchors that will be inserted in the medial row. A punch may be employed adjacent to the articular margin of the humerus and at about 45° angle to form the two pilot holes. 
     Subsequent to the formation of the pilot holes, and as shown in  FIGS. 3 and 4 , a swivel implant  30 , loaded with a strand of suture tape  40 , preferably Arthrex FiberTape, is placed in the medial pre-formed hole  32 . Arthrex FiberTape is a high strength suture tape which is braided and rectangular-like in cross section and is disclosed in U.S. Pat. No. 7,892,256, the disclosure of which is incorporated by reference herein. However, the anchor of the present invention can be used with any type of flexible material or suture. The driver is then rotated to advance screw  42  down shaft  20  to secure the implant and suture in the bone hole. More specifically, as shown in  FIG. 4   a , the screw  42  is advanced by holding thumb pad  50  as the driver handle  22  is turned clockwise. An Arthrex FiberLink and an Arthrex Scorpion suture passer  44 , are used to shuttle both tails of the suture tape through the rotator cuff  34  simultaneously. This procedure is followed for both medial swivel anchors. 
     Referring to  FIG. 5 , one tail of suture tape  40  from each medial swivel anchor is retrieved and loaded through the eyelet of another swivel implant  30 , and that implant is installed in then inserted into a preformed lateral bone socket. The tension of the suture tape  40  is adjusted if necessary. The swivel anchor driver is then rotated in clockwise direction as before to advance the screw  42  over the implant to complete insertion. This step is repeated in another lateral bone socket with the other tails of suture tape from each medial anchor. The tails of the suture tape  40  are then cut, one at a time, to complete the construct as shown in  FIG. 6 . The method is analogous to the method disclosed in U.S. Pat. No. 8,012,174, the entire disclosure of which is incorporated by reference herein.  FIGS. 12 and 13  provide additional illustrations of the swivel anchor assembly and the anchor inserted in a bone socket, respectively. 
     The swivel anchor and instruments of the present invention are now described in greater detail. As shown in  FIGS. 7(   a )-( f ), a driver  68  is used to install the knotless fixation devices with a swiveling implant. Driver  68  features a thin cannulated rod  20  passing slidably and rotatably through a cannulated driver assembly. The tip of thin cannulated rod  20  is adapted to accept swivel anchor implant  30  within the cannulation at its tip, preferably via a snap fit. Cannulated rod  20  has a hexagonal outer surface for receiving anchor body (preferably a screw)  42  having a corresponding cannulation.  FIG. 10  illustrates a detailed view of the cannulated screw  42 . 
     During installation of the knotless anchor having a swiveling implant  30 , the screw  42  is first inserted onto cannulated rod  20  of the driver  68 . As shown in  FIGS. 7(   a ) and ( b ), screw  42  is loaded onto rod  20  and then fully seated on the shaft end of the driver.  FIG. 7(   c ) illustrates the swivel anchor implant  30 . As shown in  FIGS. 8-9 , traction sutures  71  extending from the proximal end of the swivel anchor implant  30  are threaded through the cannulation of the driver  68  (see also  FIG. 7(   c )). These traction sutures  71  prevent inadvertent separation of the implant  30  from the driver during insertion, but they can be used subsequently for additional tie-down of the tendon after the driver is removed. Subsequently, the swivel anchor implant  30  is seated on the driver tip and until advanced until it snaps onto place ( FIG. 7(   d )). A protective tube  94  ( FIG. 7(   e )) may be placed over the tip of the assembly for shipping purposes. The traction sutures  71  may be looped around the driver handle, as shown in  FIGS. 7(   f ) and ( g ), and secured in a cleat  98  to prevent the implant  200  from becoming prematurely detached from the driver. 
     The knotless fixation device of the present invention advantageously minimizes or eliminates the need to tie knots. The use of such a swivel anchor also provides secure fixation of the suture construct—the secure suture construct results from the suture being pushed into a hole and held tightly by an anchors. 
     In the preferred embodiment of the present invention, as mentioned above, suture tape is used with the swivel anchor to fix tissue to bone. However, the swivel anchor of the present invention can be used with any type of flexible material or suture. In another preferred embodiment, an allograft or biological component may be used instead of suture or tape. The allograft or biological component may be comprised of tendon or pericardium, for example, which provides improved tissue repair. In yet additional embodiments, any combination of suture, suture tape, and allograft or biological component may be employed, depending on the characteristics of the specific surgical repair and/or as desired. 
       FIG. 11  illustrate a swivel implant  500  which is provided with a pointed metal tip to facilitate insertion of the implant without the need to pre-drill or pre-form a hole in the bone. The conical configuration of the most distal end pointed tip  550  allows the implant to undergo a self-punching operation, eliminating any need to pre-drill a hole in the bone. The conical configuration of the most distal end of the pointed tip implant  550  also provides suture fixation strength, as well as accelerated graft/tendon healing to bone. The pointed tip implant  550  may be detachable from the driver. 
     As illustrated in  FIGS. 11(   a )-( e ), pointed tip implant  500  is provided with a metal tip  550  and an eyelet or aperture  555  for receiving suture or suture tape. Pointed tip implant  550  is also provided, at its most distal end, with a conical portion  551  which allows direct advancement of the implant (by simply tapping the device with a mallet, for example) without the formation of a pilot hole in bone. Preferably, the conical portion  551  of the implant is formed of titanium or titanium alloy. In a preferred embodiment, eyelet or aperture  555  is also formed of titanium or similar material, to withstand impaction forces during the graft fixation procedure. 
     Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein.