Abstract:
Knotless fixation of soft tissue to bone is accomplished using a bone anchor configured to provide interference fixation of a soft-tissue connector. The soft-tissue connector is provided in the form of a flat narrow piece of material. Additional fixation strength can be provided by configuring the bone anchor to penetrate into or through the soft-tissue connector. The bone anchor is installed into a pre-formed hole or socket in the bone.

Description:
This application claims the benefit of U.S. Provisional Appl. No. 60/580,349 filed Jun. 18, 2004, the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to apparatus and methods for tissue repair, and more particularly to techniques using knotless anchors for fixation of soft tissue to bone. 
     2. Description of the Related Art 
     When tissue structures such as tendons or ligaments (“soft” tissues), detach from bone-tissue structures (“hard” tissue), it may become necessary to reconnect the structures surgically. Techniques and devices that have been developed generally involve knotting suture to anchor the soft tissue to the hard tissue. Reattachment with suture, and the knot-tying involved, can present significant difficulties. Operating in the shoulder joint space, for example, particularly arthroscopic surgery, can be very challenging. It would be beneficial to surgically-anchor tissue torn from bone without the need to tie knots in suture. 
     Knotless methods and apparatus for attachment of soft and hard tissue structures are disclosed in U.S. Pat. No. 6,544,281 to ElAttrache et al, the entire disclosure of which is incorporated herein by reference. ElAttrache et al. discloses securing soft tissue to bone using lengths of suture thread. The suture thread is secured in a pre-formed socket with an anchor without the need for tying knots. The suture threads are held in place on the end of an inserter/driver using a loop of suture or by inserting ends of the suture into a distal cannula of the inserter/driver. Management of suture threads in certain surgical situations can be difficult and cumbersome. The need exists for simplified knotless anchoring apparatus and techniques that also provide broader surgical application and improved fixation strength. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention includes soft-tissue connectors, anchoring devices (anchors), instrumentation, and related surgical techniques and constructs used to secure suture to bone without the need to tie a knot in suture. An exemplary soft-tissue connector is provided in the form of a flat, narrow tape material. The tape material can be formed of suture can be configured as a webbing which is manufactured by weaving or braiding. Additionally, the soft-tissue connector can be a synthetic material for which weaving or braiding is not required. Further alternative types of soft-tissue connectors can include, without limitation, a portion or extension of the ligament, graft, or soft tissue to be fixed to bone. 
     The soft-tissue connector is attached to soft tissue and secured to bone using an anchoring device. The anchoring device is used to hold the soft-tissue connector in a pre-formed socket by interference fixation. 
     In one exemplary form, the anchoring device has a cannulated body. The cannula, formed axially through the anchor body, serves several purposes. The cannula receives an anchor driver and/or a soft-tissue connector holding device during installation. Additional anchoring fixation can be provided by a pin driven into tissue through the cannula. The anchor driver also can be cannulated to fit over a guide wire during installation. 
     The invention can be used for various reattachment purposes, including biceps tendon and rotator cuff. In an exemplary application, rotator cuff repair proceeds in the shoulder by attaching a length of soft-tissue connector to the rotator cuff. At least one limb of the soft-tissue connector extends from the attachment point on the rotator cuff. At least one pre-formed hole or socket is provided at the articular margin of the shoulder. A driver is fitted with the anchor and a guide wire. The point of the guide wire protrudes a few millimeters from the tip of the driver. 
     The limb of soft-tissue connector is extended across the pre-formed hole, and a length of the soft-tissue connector is urged into the pre-drilled socket to form a U-shaped open loop with the soft-tissue connector limb. The soft-tissue connector, preferably provided in the form of a flat, woven tape, extends generally down one side of the socket, across the bottom, and back up the other side. The length of soft-tissue connector required is adjusted so that the attached tissue is approximated toward the pre-drilled hole, adjacent the opening-edge. Instruments are provided for holding the appropriate length of soft-tissue connector in the socket prior to fixation with an anchor. With the soft-tissue connector limb held in place, the anchor is driven into the pre-drilled socket until the drive-end is flush with the outer surface of the surrounding bone. 
     Once the anchor is installed, the anchor driver is removed. The guide wire can be left in place. A cannulated pin is loaded onto the guide wire and driven into and through the cannulation of the anchor until the cannulated pin is flush with the surface of the surrounding bone. The cannulated pin pierces the soft-tissue connector to enhance fixation. The construct preferably rigidly secures a fixed length of soft-tissue connector to bone. Exposed extraneous soft-tissue connector is cut off flush to the bone surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view depicting an initial step in a method of rotator cuff repair according to the present invention; 
         FIG. 2  is a perspective view depicting a next step in a method of rotator cuff repair according to the present invention; 
         FIG. 3  is another perspective view depicting a further step in the method of rotator cuff repair subsequent to the step shown in  FIG. 2 ; 
         FIG. 4  is another perspective view depicting a further step in the method of rotator cuff repair subsequent to the steps shown in  FIGS. 1-3 , in which a cannulated pin is loaded onto a guide wire; 
         FIG. 5  is an enlarged perspective view depicting a concluding step in the method of rotator cuff repair subsequent to the steps shown in  FIGS. 1-4 , in which the cannulated pin has been installed and excess soft-tissue connector is cut off; 
         FIG. 6  illustrates use of an alternative anchoring device having a pointed tip or sharp spike for engaging soft-tissue connector by penetrating the tape and preventing slip; 
         FIG. 7  illustrates use of an anchoring device and soft-tissue connector with reinforced perforations according to an alternative embodiment of the invention; 
         FIG. 8  illustrates use of a single-limb construct according to an alternative embodiment of the invention; 
         FIG. 9  illustrates an alternative development of a single-limb construct according to an alternative embodiment of the invention; and 
         FIG. 10  illustrates use of a single-limb construct for double-row fixation according to another exemplification of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring initially to  FIG. 1 , repair of a torn rotator cuff  2  proceeds by passing a length of soft-tissue connector  4  through the detached portion of the rotator cuff  2 . An exemplary soft-tissue connector  4  is marketed as Fibertape™ by Arthrex, Inc., Naples, Fla. A pre-formed socket  6  is created at the articular margin of the shoulder. The socket can be formed by drilling or core removal, for example. 
     Referring to  FIG. 2 , an anchor driver  8  is fitted with a cannulated threaded anchor  10  disposed over a guide wire  12 . Anchor  10  also is received over an inner shaft  13  of driver  8 . The inner shaft  13  is removable from within the driver  8  and can be advanced independently of driver  8 . The tip of the guide wire  12  protrudes a few millimeters from the tip of the inner shaft  13  of driver  8 . Two limbs of soft-tissue connector  4  are overlapped across the opening of the socket  6 . 
     Referring to  FIG. 3 , the exposed tip of guide wire  12  and the tip of inner shaft  13  are used to engage and urge the overlapped limbs of soft-tissue connector  4  into the bottom of the pre-formed socket  6 . The length of soft-tissue connector urged into the socket is judged and adjusted so that the rotator cuff  2  is approximated to the preformed socket  6 . With the soft-tissue connector held in place within the socket, the threaded anchor  10  is advanced over the guide wire and driven in until flush with the surface of the surrounding bone. 
     Referring to  FIG. 4 , once threaded anchor  10  is installed into socket  6 , anchor driver  8  is removed, leaving guide wire  12  in place. A cannulated pin  14  is loaded onto guide wire  12 . Cannulated pin  14  is advanced along the guide wire  12  and driven into the cannulation of threaded anchor  10 . The cannulated pin  14  is urged flush with the surface of the surrounding bone. Preferably, the tip of cannulated pin  14  extends beyond the end of cannulated bone anchor  10  and penetrates into or through soft-tissue connector  4  to enhance securement within bone socket  6 . 
     Referring to  FIG. 5 , the reattachment is finished by trimming off the exposed ends of soft-tissue connector  4  to be flush as possible with the surrounding bone. The steps above can be repeated to provide an additional anchor fixation point as indicated. Further, the present invention is not limited to using only one length of soft-tissue connector, but includes securement of additional soft-tissue connectors with one bone anchor, for example. 
       FIG. 6  illustrates an alternative embodiment of the present invention in which a pointed-tip anchor  20  used in a method similar to that described above in connection with  FIGS. 1-5 . Pointed tip  22  of anchor  20  engages soft-tissue connector  4  at the bottom of socket  6 . Anchor  20  can be cannulated or solid. 
     Referring to  FIG. 7 , a perforated soft-tissue connector  24  can be used in place of soft-tissue connector  4 . Perforated soft-tissue connector  24  features perforations  26 . In the double-limb construct shown in  FIG. 7 , an anchor  30  has a shaped tip that is inserted through two aligned perforations  26 . A driver  32  is used to install the anchor  30  and the captured soft-tissue connector  24  into socket  6 . 
       FIG. 8  illustrates a single-limb construct according another exemplification of the present invention. A length of a soft-tissue connector  34  is passed through rotator cuff  2  and then through itself using a suture needle, for example, to form a loop. The procedure is carried out in a similar fashion to that described above in connection with  FIGS. 1-5 . An alternative single-limb construct is shown in  FIG. 9  in which soft-tissue connector  34  is provided with an eye  36 . The single-limb of soft-tissue connector  34  can be simpler to engage and penetrate than a double-limb. 
       FIG. 10  illustrates a single-limb construct used in double-row fixation according to another exemplification of the present invention. A medial socket  40  is prepared and a bone anchor  42  secures a length of soft-tissue connector  41  to the bone. The bone anchor  42  may have an eye  43  to which the soft-tissue connector  41  is secured. A lateral socket  44  is formed, and a length of the soft-tissue connector  41  is passed through the rotator cuff  2 . The soft-tissue connector  41  is secured in socket  44  using an anchor/driver assembly  46  including an anchoring device similar to those described above. The anchor/driver assembly also can be configured similar to that shown and discussed, for example, in connection with FIGS. 7-11 of U.S. Pat. No. 6,544,281 to ElAttrache et al., discussed above and incorporated herein by reference. 
     Each of the anchor configurations noted above can be provided in a screw-in or press-in configuration. In a press-in configuration, the anchor can be installed by impact pressure, using a slap-hammer, for example. Alternatively, the anchor can be pressed in with gradual application of pressure. Various bone anchor configurations and installation techniques that are known to those of skill in the art, adapted to engage and secure soft-tissue connector as described herein, can be used without limitation in connection with the present invention. 
     Although the present invention has been described in connection with preferred embodiments, many modifications and variations will become apparent to those skilled in the art. The present invention is to be limited not by the specific disclosure herein, but only by the appended claims.