Abstract:
Apparatus and methods for repairing damaged tendons or ligaments. Various repair apparatus include an elongate tensile member and a pair of anchor assemblies connected for movement along the tensile member on either side of a repair site, such as a tear or laceration. The anchor assemblies or structures may take many forms, and may include barbed, helical, and crimp-type anchors. In the preferred embodiments, at least one anchor structure is movable along the elongate tensile member to assist with adjusting a tendon segment to an appropriate repair position and the anchor structure or structures are then lockable onto the elongate tensile member to assist with affixing the tendon at the repair position. Tendon and/or ligament-to-bone repair apparatus and methods employ similar concepts.

Description:
The present application is a divisional of U.S. application Ser. No. 10/816,725 filed on Apr. 2, 2004 now U.S. Pat. No. 7,611,521 which is a continuation of PCT Serial No. PCT/US02/31481 filed on Oct. 2, 2002 (expired) which is a continuation-in-part of U.S. application Ser. No. 09/969,947, filed on Oct. 3, 2001 (now U.S. Pat. No. 6,984,241) which is a continuation-in-part of PCT Serial No. PCT/US99/24098 filed on Oct. 18, 1999 (expired) which is a continuation-in-part of U.S. Ser. No. 08/928,866, filed on Sep. 12, 1997 (now U.S. Pat. No. 6,083,244) which is based on Provisional Patent Application Ser. No. 60/026,101, filed Sep. 13, 1996 (expired) and Provisional Patent Application Ser. No. 60/043,086, filed on Apr. 8, 1997 (expired). The disclosures of each of these prior related applications are hereby fully incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to tendon or ligament repair apparatus and methods. More specifically, the invention relates to the repair of severed or otherwise damaged tendons or ligaments and the attachment of tendons or ligaments to bone. As used in the specification and claims, the terms “tendon” and “ligament” are used in an interchangeable manner. 
     BACKGROUND OF THE INVENTION 
     The repair of tendons or ligaments is a challenging and complication-prone area of surgery. Over the past 40 years, improvements in the art of tendon and ligament repair have focused primarily on suture techniques used to repair tendons and ligaments. Tendons can sustain high tensile forces resulting from muscle contraction, yet are flexible enough to bend around bony surfaces and deflect beneath retinacula to change the final direction of muscle pull. Tendons attach muscle to bone and transmit tensile loads from muscle to bone, thereby producing joint movement. Ligaments attach bone to bone and can flex to allow natural movement of the bones that they attach, but are strong and inextensible so as to offer suitable resistance to applied forces. Ligaments augment the mechanical stability of the joints. 
     Bundles of collagen fibers embedded in a connecting matrix, known as ground substance, provide the load carrying elements of natural tendons and ligaments. The tensile strength of tendons and ligaments is provided by the lengthwise parallel collagen fibers, which give them the ability to withstand high tensile loads. The arrangement of collagen fibers is nearly parallel in tendons, equipping them to withstand high unidirectional loads. The less parallel arrangement of the collagen fibers in ligaments allows these structures to sustain predominant tensile stresses in one direction and smaller stresses in other directions. The ground substance in both tendons and ligaments acts generally as a cementing matrix to hold the collagen fibers together. 
     Today, the most common methods of repairing torn, severed or otherwise damaged tendons involve approximating the severed ends of the tendons and suturing one side of the tendon to the other, thereby returning the tendon to its natural position. Most suture methods employ an internal suture with external knots distal and proximal to the laceration, or within the laceration. Most sutures typically include a continuous running external suture at the junction of the repair, known as an epitendinous suture, to approximate the tendon ends. Other methods of repairing a damaged tendon involve the placement of prosthetic material either within or around the tendon. Whether prosthetics are used or the repair is done using only sutures, both methods involve external sutures or knots which have the disadvantage of creating sites for the development of adhesions, the growth of cells around the foreign material, as a result of the body&#39;s natural healing process. The development of adhesions and the external foreign material promote increased work of flexion of the repaired tendons and ligaments. Increased risk of adhesions and increased work of flexion is exacerbated when the number of suture strands increases, or the amount of suture material or prosthetic material is increased, as is commonly done to affect a stronger repair. 
     The effectiveness of sutures depends upon many factors, including the techniques used to create the sutures. These techniques are difficult to master and very tedious to perform. The use of internal or external prosthetic splints also pose increased risk for the development of adhesions, and large slits that are created for the insertion of splints within the tendons create risk of structural damage to the internal blood supply, which may cause tissue degeneration. 
     Another problem of conventional tendon repair methods relates to the softening of the damaged tendon ends, which begins shortly after the damage or injury occurs and continues for approximately 12 days. This softening results in a weakening of the tendon fibers, which may contribute to the formation of a gap at the repair site during the early phases of tendon healing. It is believed that gaps form at the repair site due to a loss of purchase by the grasping portion of the suture at the tendon-suture interface. The grasping suture may even completely tear out, resulting in a failure of repair called “rake out.” 
     The ideal repair for a tendon or ligament is one which exhibits high strength, high flexibility, and the ability to join the ends of the tendon or ligament without any foreign material on the outside surface of the tendon or ligament. Current and past tendon or ligament repair techniques have concentrated on increasing the tensile strength of the repair by adding more structural components to the repair (for example, sleeves, splints, additional suture strands, additional knots). All of these techniques trade off between early tensile strength at the repair site and increased work of flexion and increased risk of adhesions or other problems. None of these techniques have utilized the physiological make up of the tendon to provide a stronger repair. 
     The attachment of tendons, ligaments, and other soft tissue to bone, such as in arthroscopic shoulder stabilization or rotator cuff repair, presents problems similar to those experienced in intra-tendon or intra-ligament repair. In this regard, simply suturing soft tissue to a bone anchor or using external soft tissue anchor members may not provide the necessary strength of repair. These techniques also promote the formation of adhesions on tendons ligaments, and other soft tissue and increase the work of flexion of the tendons and ligaments, as discussed above. 
     Finally, retrieval of soft tissue has also been a problematic area of repair surgery. Typically, a surgeon must use a small grasping tool with thin, movable jaws similar to needle-nose pliers to grasp the end of the soft tissue and pull and transfix it in an appropriate operating position. Unfortunately, gripping soft tissue in this manner often damages the tissue and makes the tissue less able to hold the epitendinous suture. These damaged ends will also form scar tissue or adhesions which further adversely affect the repair. 
     There is thus a need for tendon repair techniques and apparatus that utilize harness the intrinsic strength of soft tissue fibers, but allow the tendon to flex while moving. These repair apparatus should resist any gapping or rupture during immediate post-operative physical therapy, and reside in the interior of the soft tissue to reduce or possibly eliminate post-operative adhesions. The repair apparatus should also produce low work of flexion while gliding unhindered through the tendon sheaths. There is generally a need for soft tissue repair apparatus and methods that allow the patient to immediately begin active physical therapy without risking any tendon repair failure while minimizing or eliminating the need for sutures or other repair structure on the external surfaces of the soft tissue, thereby reducing the formation of adhesions. There is a further need for soft tissue-to-bone repair techniques and apparatus with at least some of these attributes. Finally, there is a need for a soft tissue retrieval device which also utilizes the inherent strength of the fibers and minimizes damage to the retrieved end of the soft tissue. 
     SUMMARY OF THE INVENTION 
     The present invention provides various apparatus and methods for repairing torn, or otherwise damaged, tendons, ligaments and other soft tissue wherein the inventive apparatus and methods overcome various drawbacks of the prior art. Although various aspects of this invention are discussed with respect to illustrative tendon and ligament repair, it will be appreciated that the invention is generally applicable to other soft tissue procedures as well. 
     In one aspect of the invention, a soft tissue anchor assembly has an anchor configured to be inserted within the interior of a tendon or ligament and a retaining member which is coupled to the anchor such that when the anchor and retaining member are driven into a tendon or ligament, the anchor assembly grasps and holds the fibers of the tendon or ligament between the anchor and the retaining member. In an exemplary embodiment, the anchor comprises one or more helical coils which may be driven into the interior of the tendon or ligament to gather fibers as it is rotated and translated into the tendon or ligament. The retaining member includes a slot for engaging a drive tool such that the retaining member and helical anchor may be simultaneously driven into a tendon or ligament with the drive tool. 
     In further accordance with the invention, the soft tissue anchor assembly is coupled to an elongate tensile member such as a flexible, multi-filament suture, and is secured to the elongate tensile member by a stop member to thereby fix the location of the elongate tensile member relative to the anchor assembly. The stop member may be secured to the elongate tensile member by various methods, such as crimping the stop member or by engagement of the stop member with a contoured surface of the elongate tensile member. Alternatively, the soft tissue anchor assembly itself may be constructed for securing the anchor assembly to an elongate tensile member. 
     In another aspect of the invention, a soft tissue anchor assembly includes a helical anchor and an expandable retaining member coupled to the helical anchor. The retaining member is expandable from a contracted state, wherein fibers of the tendon or ligament may be received between the retaining member and the helical anchor when the anchor assembly is driven into a tendon or ligament. The retaining member may then be expanded to compress the fibers of the tendon or ligament against the coils of the helical anchor to thereby secure the anchor assembly within the tendon or ligament. 
     In yet another aspect of the present invention, an exemplary soft tissue anchor assembly includes an anchor body having a bore extending through the body for coupling the anchor assembly to an elongate tensile member. The anchor assembly further includes a plurality of barbs which extend outward from the body and which are configured to grasp fibers of the tendon or ligament when the anchor assembly is driven into the tendon or ligament. 
     In accordance with the present invention, the various soft tissue anchors may be used with elongate tensile members to repair severed tendons or ligaments wherein one or more of the exemplary anchor assemblies are inserted into each of the segments of a severed tendon or ligament, elongate tensile members are coupled between anchor assemblies on respective segments of the tendon or ligament, and are secured to anchor assemblies on one of the segments. Tension is applied to the elongate tensile members to approximate the tendon or ligament segments and the remaining anchor assemblies are secured to the elongate tensile member to fix the position of the segments relative to one another. In one aspect, the soft tissue anchors may be inserted into a tendon or ligament through a longitudinal surface of the tendon or ligament. In another aspect, the soft tissue anchors may be inserted within a tendon or ligament through a severed end of a tendon or ligament. 
     In another aspect of the invention, various apparatus and methods for securing tendons or ligaments to bones are provided. In one exemplary method, the soft tissue anchors are used in conjunction with elongate tensile members to secure a tendon or ligament to a bone. According to this method, the surface of the bone is prepared, such as by abrading the surface or forming a trough within the surface, and holes are drilled through the bone. The soft tissue anchors are installed within the tendon or ligament and coupled to the elongate tensile members, as described above, and the elongate tensile members are routed through the holes in the bone. The elongate tensile members then may be tensioned to approximate the tendon or ligament to the bone and then secured to fix the location of the tendon or ligament. The elongate tensile members may be secured to the bone using, for example, washers secured to the ends of the elongate tensile members, or they may be looped through the holes back toward the tendon or ligament to be secured to the tendon or ligament by other soft tissue anchor assemblies, which have been installed within the tendon or ligament. 
     In yet another aspect of the invention, tendons or ligaments may be secured to a bone using a bone anchor. Various exemplary bone anchors are provided for securing tendons or ligaments in this manner. In one exemplary embodiment, a bone anchor includes an anchor body having a bore extending through the body for coupling the body with an elongate tensile member. The anchor further includes one or more projections which extend outwardly from the body to engage the bone. The bone anchor may be inserted within a hole which has been formed in the bone and the projections engage the bone to prevent removal of the anchor from the bone. 
     In another exemplary embodiment, the bone anchor includes a flared aperture at one end through which an elongate tensile member coupled to the anchor may extend for connection to a tendon or ligament. Advantageously, the flared aperture permits attachment of the tendon or ligament adjacent the bone anchor without exposing the elongate tensile member to sharp edges. In another exemplary embodiment, the bone anchor further includes a swivel member rotatably coupled to an end of the bone anchor. An elongate tensile member coupled with the bone anchor may extend through an aperture in the swivel member to secure a tendon or ligament adjacent the bone while preventing damage to the elongate tensile member. In yet another exemplary embodiment, the bone anchor includes means for securing an elongate tensile member directly to the bone anchor, such as by crimping onto the elongate tensile member or engaging a contoured surface of the elongate tensile member. 
     According to one exemplary method for securing a tendon or ligament to a bone, a bone anchor is attached to a bone and a soft tissue anchor is inserted within a tendon or ligament. The bone anchor and soft tissue anchor are coupled together by an elongate tensile member and tension is applied to the elongate tensile member to approximate the tendon or ligament to the bone. 
     In another aspect of the invention, there is provided an anchor for attaching a tendon, ligament or other soft tissue directly to a bone. The exemplary anchor includes a first portion that is configured to engage the bone, and a second portion that is configured to engage the soft tissue. The first portion includes an elongate shaft having screw threads, barbs, or other structure disposed along the length of the shaft for securing the anchor to the bone. The second portion includes a soft tissue anchor assembly having a helical anchor and a retaining member coupled to the helical anchor, whereby fibers of the soft tissue may be grasped and firmly held between the helical anchor and the retaining member, as described above. According to an exemplary method, the anchor may be used to secure a glenoid labrum to a glenoid socket, whereby the anchor is installed through the glenoid labrum such that the soft tissue anchor assembly becomes attached to and compresses the glenoid labrum and the first portion of the anchor is driven for attachment into the bone. In one embodiment, the first and second portions of the bone anchor are integrally formed. In another exemplary embodiment, the first and second portions are separate and may be coupled together prior to installation within the soft tissue, or they may be coupled together after the second portion has been inserted within the soft tissue. 
     In yet another aspect of the invention, an exemplary apparatus for attaching a tendon or ligament to a bone includes an elongate tensile member having a first end configured to be driven through soft tissue and bone when the elongate tensile member is rotated about its longitudinal axis, a soft tissue anchor couplable to the elongate tensile member, and at least one stop member securable to the elongate tensile member to fix the position of the elongate tensile member relative to the soft tissue anchor. According to one exemplary method for using this apparatus, a glenoid labrum is attached to a glenoid socket by installing the elongate tensile member through the glenoid socket and glenoid labrum, the soft tissue anchor is inserted within the glenoid labrum, the elongate tensile member is coupled to the soft tissue anchor, and tension is applied to the elongate tensile member to approximate the glenoid labrum and glenoid socket. The opposite end of the elongate tensile member may be secured to the bone using a washer secured with a stop member. 
     The present invention also provides various tools for facilitating the repair of damaged tendons, ligaments, and other soft tissue using the exemplary soft tissue anchors, bone anchors, elongate tensile members, and stop members of the invention. In one aspect, a tool is provided for inserting a soft tissue anchor within a tendon or ligament. The tool includes a rotatable shaft carried within a tubular housing and a needle-shaped member fixed to one end of the shaft. A soft tissue anchor assembly may be installed within one end of the housing and over the needle-shaped member to engage a drive member located near the end of the shaft. In use, the tool may be positioned within an incision made in a tendon or ligament and the anchor assembly may be driven into the tendon or ligament by manipulating a knob on the tool to rotate and translate the anchor assembly into the tendon or ligament. 
     In another exemplary embodiment, a tool for inserting a soft tissue anchor within a tendon or ligament further includes a tubular inner member disposed within the shaft and having an inner channel sized to receive an elongate tensile member. The tubular inner member may be extended beyond the end of the housing to drive an elongate tensile member having a sharpened tip through the tendon or ligament after the soft tissue anchor has been inserted within the tendon or ligament. 
     Another exemplary tool of the invention is useful for crimping stop members onto elongate tensile members. The exemplary tool includes first and second jaws which are movable toward each other. The first jaw is configured to receive and hold a stop member and the second jaw is configured to collapse the crimp member when first and second handles of the tool are manipulated to move the first and second jaws together. 
     In yet another exemplary embodiment, a retrieval tool is provided for removing an anchor from within a tendon or ligament, as may be desired when the anchor is misinstalled. The retrieval tool includes a shaft having a handle portion at one end and a tool driver portion at the other end for engaging the soft tissue anchor. A needle-shaped member extending from the tool driver portion is configured to couple with a soft tissue anchor which has been installed in a tendon or ligament and the retrieval tool may be manipulated to rotate the soft tissue anchor in a direction which causes the soft tissue anchor to back out of the tendon or ligament. 
     In yet another exemplary embodiment, a tool for crimping a stop member and cutting an elongate tensile member is provided. The exemplary tool includes an elongate housing having a first end configured to receive a stop member and an elongate tensile member threaded through the stop member. The tool further includes a crimp bit and a cutting member movably disposed near the first end of the housing and configured to crimp the stop member and cut the elongate tensile member when an actuating lever is manipulated by the user. 
     In yet another exemplary embodiment, a loading tool is provided for loading stop members within the first end of the crimping-and-cutting tool. The loading tool includes a first pin which receives a stop member and a second pin which engages the spring-loaded crimp bit on the crimp-and-cut tool to move the crimp bit away from the crimping jaw whereafter the stop member may be positioned within the crimp jaw by the first pin. 
     In another aspect of the present invention, a method for repairing a rotator cuff is provided. According to the exemplary method, a soft tissue anchor is installed within a tendon of the rotator cuff, a bone anchor is installed within the head of the humerus bone, an elongate tensile member is coupled to the soft tissue anchor and to the bone anchor, tension is applied to the elongate tensile member to approximate the rotator cuff to the humerus, and stop members are secured to the elongate tensile member to fix the position of the elongate tensile member relative to the bone anchor and the soft tissue anchor. 
     These and other advantages, objectives and features of the invention will become more readily apparent to those of ordinary skill upon review of the following detailed description of illustrative embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a unitary anchor assembly comprising a helical anchor coupled for insertion with a core portion, or tendon fiber-retaining member; 
         FIG. 2  is an elevational view of the unitary anchor assembly of  FIG. 1 , illustrating detail of the anchor assembly; 
         FIGS. 3-4  are perspective views of another exemplary anchor assembly of the present invention; 
         FIG. 5  is a cross-sectional view of the anchor assembly of  FIGS. 3-4 ; 
         FIG. 6  is a perspective view of yet another exemplary anchor assembly of the present invention; 
         FIG. 7  is a perspective view of another exemplary anchor assembly, similar to the anchor assembly of  FIG. 6 ; 
         FIG. 8  is a perspective view of an exemplary stop member of the present invention; 
         FIG. 9  is a perspective view showing an insertion tool for inserting the assembly of  FIG. 1  into a tendon or ligament; 
         FIG. 10  is a cross-sectional view generally taken along the longitudinal axis of the insertion tool shown in  FIG. 9 ; 
         FIG. 10A  is an enlarged view, partially cross-sectioned, of the distal end of the tool shown in  FIG. 10 ; 
         FIG. 11  is a perspective view illustrating the tool of  FIG. 9  being used on a tendon or ligament; 
         FIG. 12A  is an enlarged cross-sectional view of the tool of  FIG. 9  being used to drive the unitary anchor assembly of  FIG. 1  into a tendon or ligament; 
         FIG. 12B  is a partial cross-sectional view, similar to  FIG. 12A , illustrating the anchor assembly inserted into the tendon or ligament and secured to a tensile member; 
         FIG. 13A  is a side elevational view schematically showing an alternative pistol grip assembly for the insertion tool of  FIG. 9  allowing one-handed operation by a surgeon; 
         FIG. 13B  is a fragmented end view of the pistol grip assembly of  FIG. 13A  schematically illustrating the interaction between the rack and pinion drive; 
         FIGS. 14A-14G  are perspective views illustrating a tendon or ligament repair method utilizing two unitary anchor assemblies and an elongate, flexible tensile member; 
         FIG. 15  is an enlarged perspective view showing the jaw portion of a crimp tool and a crimpable stop member, each constructed in accordance with additional aspects of the invention; 
         FIG. 16  is a perspective view of an anchor assembly removal tool in accordance with another aspect of the invention; and 
         FIG. 17  is an enlarged perspective view of the distal end of the removal tool of  FIG. 16  and the unitary anchor assembly of  FIG. 1 ; 
         FIGS. 18A-18E  are schematic illustrations depicting an exemplary method for repairing a severed tendon or ligament using exemplary apparatus of the invention; 
         FIG. 19  is a perspective view of an exemplary tool for inserting a soft tissue anchor into, and driving a tensile member through, a tendon or ligament; 
         FIGS. 20A-20D  are cross-sectional illustrations depicting operation of the tool of  FIG. 19  to insert a soft tissue anchor into a tendon or ligament and to drive a tensile member through the tendon or ligament; 
         FIG. 20E  is a partial cross-sectional view of the tool of  FIG. 19 , illustrating an alternative embodiment having extendable barbs; 
         FIG. 21  is perspective view, partially cross-sectioned, of an exemplary tool for crimping a stop member on a tensile member and cutting the tensile member; 
         FIGS. 22A-22C  are cross-sectional detail views of the exemplary tool of  FIG. 21 , illustrating use of the tool to crimp a stop member and cut a tensile member; 
         FIG. 23A  is a perspective view of an alternate embodiment of the tool of  FIG. 21 , further depicting an exemplary tool for loading a stop member onto the tool; 
         FIG. 23B  is an enlarged perspective view of the end of the tool of  FIG. 23A , illustrating the loading tool coupled to its end; 
         FIGS. 23C-23E  are enlarged, cross-sectional views of the crimping tool and loading tool of  FIG. 23A , illustrating use of the loading tool to load a stop member into the crimping tool; 
         FIG. 23F  is an enlarged cross-sectional view of the crimping tool of  FIG. 23A , illustrating use of the tool to crimp a stop member and cut a tensile member; 
         FIG. 23G  is a perspective view of an alternate embodiment of the loading tool of  FIG. 23A ; 
         FIGS. 24A-24D  are schematic illustrations depicting another exemplary soft tissue anchor assembly of the present invention and a method of installing the anchor assembly in a tendon or ligament; 
         FIG. 24E  is a schematic illustration of a cross-section of the soft tissue anchor assembly of  FIGS. 24A-24D , depicting a retaining member of the anchor assembly in an expanded condition; 
         FIG. 24F  is a schematic illustration of the soft tissue anchor assembly of  FIGS. 24A-24E  being used with a bone anchor to approximate a tendon or ligament; 
         FIGS. 25A-25B  are schematic illustrations depicting an exemplary method of repairing a torn Achilles tendon using exemplary apparatus of the present invention; 
         FIGS. 26A-26B  are schematic illustrations depicting another exemplary method of repairing a torn Achilles tendon using exemplary apparatus of the present invention; 
         FIGS. 27A-27B  are schematic illustrations depicting an exemplary method of repairing a rotator cuff using exemplary soft tissue anchors of the present invention; 
         FIGS. 28A-28B  are schematic illustrations depicting other exemplary methods of repairing a rotator cuff using exemplary soft tissue anchors of the present invention; 
         FIGS. 29A-29B  are schematic illustrations depicting an exemplary method of repairing a rotator cuff using a bone anchor and exemplary soft tissue anchors of the present invention; 
         FIGS. 30A-30B  are cross-sectional views depicting exemplary bone anchors of the present invention and exemplary methods for approximating a tendon or ligament to a bone using the bone anchors; 
         FIG. 31  is a cross-sectional view of another exemplary bone anchor of the present invention, illustrating a method of approximating a tendon or ligament to a bone using the anchor; 
         FIGS. 32A-32B  is a schematic illustration depicting yet another bone anchor of the present invention, and an exemplary method of using the bone anchor to approximate a tendon or ligament to a bone; 
         FIG. 32C  is a schematic illustration of another exemplary bone anchor of the present invention, having screw threads for attachment to a bone; 
         FIG. 32D  is a schematic illustration depicting yet another exemplary bone anchor of the present invention, configured to be secured to a tensile member having a series of teeth disposed along its length; 
         FIG. 33  is an elevational view of an exemplary anchor of the present invention, configured to attach a tendon or ligament directly to a bone; 
         FIG. 34  is a schematic illustration depicting an exemplary method of attaching a glenoid labrum to a glenoid socket using the anchor of  FIG. 33 ; 
         FIG. 35A  is an elevation view of an exemplary apparatus for attaching a glenoid labrum to a glenoid socket; 
         FIG. 35B-35C  are schematic illustrations depiction various methods of using the apparatus of  FIG. 35A  to attach a glenoid labrum to a glenoid socket; 
         FIG. 36  is a schematic illustration depicting the repair of rotator cuff according to an exemplary method of the present invention; 
         FIG. 37  is a schematic illustration depicting the tool of  FIG. 19  being used to install a soft tissue anchor, according to the exemplary method of rotator cuff repair; 
         FIG. 38-39  are perspective views further illustrating use of the tool of  FIG. 19  according to the exemplary method of rotator cuff repair; 
         FIG. 40  is a schematic illustration further depicting the exemplary method of rotator cuff repair and use of the tool of  FIG. 21  to secure a stop member to a tensile member according to the method; 
         FIG. 41  is an enlarged detail view of the repair site  FIG. 40 , illustrating the routing of a tensile member through a bone anchor and tissue anchor, according to the exemplary method; 
         FIG. 42  is a schematic illustration depicting the use of the tool of  FIG. 21  to approximate the rotator cuff tendon and secure a stop member, according to the exemplary method; 
         FIG. 43  is a schematic illustration depicting a rotator cuff tendon which has been approximated to a humerus bone according to the exemplary method; 
         FIGS. 44A-44B  are schematic illustrations depicting another exemplary method for repairing a rotator cuff, wherein a tensile member is routed through a bone anchor and a tissue anchor using a shuttle suture; 
         FIG. 45  is a schematic illustration further depicting use of the shuttle suture of  FIGS. 44A-44B  to route the tensile member according to the exemplary method; 
         FIG. 46  is a schematic illustration depicting yet another method of using a shuttle suture to route a tensile member during a rotator cuff repair; 
         FIGS. 47A-47B  are schematic illustrations depiction other exemplary methods of securing a rotator cuff tendon to a bone anchor during a rotator cuff repair; 
         FIGS. 48-50  are a partial section views depicting other exemplary soft tissue anchors of the present invention; 
         FIG. 51  is a partial section view depicting another exemplary anchor of the present invention configured to secure soft tissue to bone; 
         FIGS. 52A-52C  are schematic illustrations depicting another exemplary apparatus and method for securing soft tissue to bone and including an expandable bone anchor; 
         FIG. 53  is a perspective view of yet another exemplary apparatus of the present invention, including a soft tissue anchor having an expandable retaining member; 
         FIGS. 54A-54B  are partial section views of the apparatus of  FIG. 53 , illustrating operation of the expandable retaining member; and 
         FIG. 55  is a partial section view of an alternative embodiment of the apparatus of  FIG. 53 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to  FIGS. 1 and 2 , an exemplary embodiment of the invention is described in connection with tendon-to-tendon or ligament-to-ligament repair. In this embodiment, a soft tissue anchor assembly  10  comprises a helical anchor  12  and a core portion or tendon fiber retaining member  14 . Helical anchor  12  has proximal and distal ends  16 ,  18  and retaining member  14  likewise has proximal and distal ends  20 ,  22 . The distal end  18  of helical anchor  12  extends distally beyond the distal end  22  of retaining member  14  and is sharpened to a point  24  to aid in insertion. In addition, retaining member  14  is tapered at its distal end  22  creating a space  26  between coils  13  of the helical anchor  12  and the outside surface  28  of the retaining member  14  for receiving and retaining tendon or ligament fibers therein, at least at a location near distal ends  18 ,  22  as will be discussed more fully below. 
     The proximal end  16  of helical anchor  12  is fixed to retaining member  14  at its proximal end  20 . This may be accomplished in various ways, however, in the preferred embodiment, the proximal end  16  of helical anchor  12  is retained in a slot  30  that extends along a longitudinal axis of retaining member  14  and is welded such as through a laser or resistance welding operation. The proximal end  20  of retaining member  14  further includes a slot  32  for receiving an insertion tool and, if necessary, a removal tool to be described below. Retaining member  14  includes a central longitudinal bore  34  for receiving an elongate, preferably flexible, tensile member as will be described more fully below. The retaining member  14  may be secured to the tensile member by a crimpable stop member  60  provided as a separate member or it may be integral with retaining member  14 , as described in copending application Ser. No. 09/969,947, or a different type of locking member may be used instead. 
     Referring to  FIGS. 3-4 , there is shown another exemplary soft tissue anchor assembly  10   a  of the present invention. Soft tissue anchor assembly  10   a  is similar to the assembly  10  of  FIGS. 1 and 2  and similar components have been correspondingly numbered. The tissue anchor assembly  10   a  comprises first and second helical anchors  12 ,  12   a  coupled to a retaining member  14   a . The helical anchors  12 ,  12   a  are arranged so that the coils  13   a  of the second helical anchor  12   a  are disposed between corresponding coils  13  of the first helical anchor  12 , as best seen in  FIGS. 3 and 5 . As shown in  FIG. 5 , the second helical anchor  12   a  has a coil diameter which is greater than the coil diameter of the first helical anchor  12 , however the helical anchors  12 ,  12   a  are otherwise similar. Proximal ends  16 ,  16   a  of the first and second helical anchors  12 ,  12   a  are secured to the retaining member  14   a  within slots  30 ,  30   a  at the proximal end  20  of the retaining member  14   a , as best seen in  FIG. 4 . 
     Another exemplary soft tissue anchor assembly  40  is shown in  FIG. 6 . The anchor assembly  40  includes an anchor body  42  having a first end  44  and second end  46 . In the exemplary embodiment shown, the anchor body  42  tapers from the second end  46  toward the first end  44  to form a generally frustoconically-shaped section. Several barbs extend radially outward from the outer surface of the body and along a circumferential direction of the body so that when anchor assembly  40  is inserted into a tendon or ligament, rotation of the anchor assembly  40  within the tendon or ligament will cause the barbs  48  to engage the fibers of the tendon or ligament. The anchor assembly  40  further includes a central bore  50  extending longitudinally along the body  42  and between the first and second ends  44 ,  46 . The central bore  50  is sized for coupling the anchor assembly  40  to an elongate tensile member, such as a flexible suture. In an exemplary embodiment, anchor assembly  40  is formed from an absorbable, or biodegradable, material, such as polylactide or any other suitable material, as is known in the art. While anchor assembly  40  is particularly suited to being formed from an absorbable material, it will be appreciated that any of the implantable devices described herein may be formed from such material. 
     With reference to  FIG. 7 , there is shown an exemplary anchor assembly  40   a , similar to the anchor assembly  40  of  FIG. 6 . The anchor assembly  40   a  further includes a second body section  52  adjacent the second end  46  of the anchor body  42  and tapered in a direction opposite the first body section  42 . A central bore  50   a  extends longitudinally through the second body section  52  and communicates with the bore  50  of anchor body  42  to provide a continuous passage by which the anchor assembly  40   a  may be coupled to an elongate tensile member. 
     In  FIG. 8  there is shown an exemplary crimpable stop member  60  having a generally cylindrical shape and including a central bore  62  through the stop member  60  for coupling the stop member  60  to an elongate tensile member. Stop member  60  further includes a circumferential groove  64  which facilitates crimping the stop member on an elongate tensile member and also facilitates registration of the stop member  60  with a crimp tool which will be described below. 
       FIGS. 9 ,  10  and  10 A illustrate an exemplary anchor assembly insertion tool  70  for inserting soft tissue anchors, such as anchor assembly  10 ,  10   a  of  FIGS. 1-4 , within a tendon or ligament. Insertion tool  70  comprises an elongate body portion  72  having a rotatable knob  74  at a proximal end  76  and having a needle-shaped drive portion  78  (see  FIG. 10 ) at a distal end  80 . The tool  70  may be provided with a guard  81  fixed to the distal end  80 , as depicted in  FIG. 9 , to protect the drive portion  78  prior to use. A flexible cable or shaft  82  is coupled between knob  74  and needle-shaped drive portion  78  and, in the preferred embodiment, this flexible shaft  82  is both rotated and translated as knob  74  is rotated in the direction of arrows  84  (see  FIG. 10 ). A threaded coupling  86  within the elongate body portion  72  allows the simultaneous rotation and translation around and along axis  88  as knob  74  is rotated. Needle-shaped drive portion  78  is rigidly affixed to flexible shaft  82 , as shown in  FIG. 10A , through the use of a coupling member  90  and, preferably, an anchor assembly, such as anchor assembly  10  shown in  FIGS. 1-2 , is retained within a curved, tubular housing  92  which does not rotate but retains rotatable shaft  82  therein. 
     As shown in  FIG. 1A , needle-shaped drive portion  78  includes a needle  94  which extends through anchor assembly  10  and further includes a projecting portion  96  which is complimentary to the tool engaging slot portion  32  of anchor assembly  10  (shown most clearly in  FIGS. 1 and 4 ). The projecting portion  96  fits within slot  32  to allow rotation and translation of anchor assembly  10  as the needle  94  is both rotated and translated into a tendon or ligament in the direction of the arrow shown in  FIG. 10A . 
     As more specifically shown in  FIGS. 11 and 12A , anchor assembly  10  is rotated and translated, or moved axially, into a tendon or ligament  100  generally through an incision  110  proximate a severed end  112  and collagen fibers  114  are captured during this insertion process between the coils  13  of anchor  12  and the outside surface  28  of retaining member  14 . During the insertion process, the coils  13  expand slightly outward away from the outer surface  28  of retaining member  14  due to their inherent spring action and, also due to their spring action, the coils  13  spring back to apply a force against the tendon or ligament fibers  114  and against the outer surface  28  of the retaining member  14 . This forcefully traps fibers  114  and strengthens the connection between anchor assembly  10  and the tendon or ligament fibers  114 . 
       FIG. 12B  shows an anchor  10  installed in the tendon  100  and an elongate tensile member  116  routed through bore  34  of anchor  10  and secured with a crimpable stop member  60  as will be described in more detail below. While  FIG. 12B  illustrates separate stop member  60  crimped to the elongate tensile member  116 , it will be recognized that a stop member may alternatively be provided as an integral portion of retaining member  14  of anchor  10 , or some other type of locking member may be used as desired. 
       FIGS. 13A and 13B  illustrate a pistol grip device  120  for driving the shaft  82  of the tool  70 , generally shown in  FIGS. 9 and 10 . Device  120  replaces knob  74  and is coupled to tool  70  by a coupling  138  at the end of flexible shaft  82  to allow one-handed operation by a surgeon. In this embodiment, a firing lever  122  may be actuated toward a handle  124  with a single hand of the surgeon to rotate the firing lever  122  about a pivot  126  and thereby drive a rack gear  128  upwardly, via a connecting pin  130 , to rotate a pinion gear  132  coupled for rotation with flexible shaft  82 . In this embodiment, shaft  82  includes an externally threaded portion  134  and an internally threaded nut  136  is rigidly affixed, so as not to rotate, within device  120 . Shaft  82  extends through a tube  139  that is coupled to housing  121  by collar  137  and threaded portion  134  engages the internal threads of nut  136  and as shaft  82  rotates through the interaction of rack and pinion  128 ,  132 , shaft  82  also translates to the left, as viewed in  FIG. 13A  to move drive portion  78  and anchor assembly  10  ( FIG. 10A ) into a tendon or ligament  100 . Alternatively, if a translation mechanism were not provided, the surgeon could translate the anchor assembly  10  manually into the tendon or ligament  100  by simultaneously pushing the pistol grip handle assembly  120  while actuating the firing lever  122  to rotate shaft  82 . Other forms of pistol grip or other one-handed actuators may be used and configured in any number of ways by those of ordinary skill to simultaneously rotate and, optionally, translate shaft  82 . 
       FIGS. 14A-14G  illustrate one exemplary method out of many possible methods for utilizing anchor assembly  10  of  FIG. 1  to repair a tendon or ligament  100 . In this example, two anchor assemblies  10  are respectively driven into tendon or ligament segments  100   a ,  100   b  as shown in  FIG. 14A  and in a manner as described above. An assembly  140  comprising a distal needle  142  coupled with a flexible elongate tensile member  116 , such as a multi-filament suture, and a preset stop member, such as crimpable stop  60 , crimped onto a proximal end  144  of elongate tensile member  116  is threaded through a first one of the anchor assemblies  10  using a tool  146   a  until needle  142  is positioned between tendon or ligament segments  100   a ,  100   b  as shown in  FIG. 14A . Although it may not specifically be stated herein, it is to be understood that passing elongate tensile member  116  through an anchor assembly  10  which has been driven into a tendon or ligament  100  includes passing the elongate tensile member  116  through the tendon or ligament  100 . From the opposite side, a second tool  146   b  is used to thread a capturing member, which may be a conventional syringe or vena-puncture needle  148  having a tip  150 , through the second anchor assembly  10  and into the space  152  between tendon or ligament segments  100   a ,  100   b . The first needle  142  is then captured by inserting its end into the hollow interior of the syringe needle  148  and the connected assembly is then withdrawn through the second anchor assembly  10 , as shown in  FIGS. 14B and 14C . Alternatively, elongate tensile member  116  may be pushed through the second anchor assembly  10  without first being captured in space  152 . 
     Tendon or ligament segments  100   a ,  100   b  are then drawn together using the well-secured anchor assemblies  10  as shown in  FIGS. 14D and 14E . Anchor assembly  10  in ligament segment  100   a  is pulled by preset crimp member  60  as anchor assembly  10  in ligament segment  100   b  is pushed using a second stop member  60  and a crimp tool  160 . Exemplary crimp tool  160  is then used to crimp second stop member  60  onto the flexible elongate tensile member  116  to retain the second anchor assembly  10  in position within segment  100   b . The first anchor assembly  10  is retained in position by the preset stop member  60  as previously described. Thus, the tendon or ligament segments  100   a ,  100   b  are held at the desired positions relative to each other as determined by the surgeon. The excess length of the elongate tensile member  116  is then cut with a cutting tool  154  at a location adjacent the proximal end of the second stop member  60  as generally shown in  FIG. 14F  and, as shown in  FIG. 14G , the access incisions  110   a ,  110   b  are closed, using sutures  156 , for example, and an epitendinous suture  158 , or other means, may be used to further secure the ends of the tendon or ligament segments  100   a ,  100   b.    
       FIG. 15  shows the jaws  162 ,  164  of crimp tool  160  in more detail. A first jaw  162  includes a projection  166  for collapsing stop member  60  against a recess  168  formed in the second jaw  164 . The recess  168  in jaw  164  includes a ridge  170  which engages groove  64  on stop member  60  to help retain stop member  60  in place within the jaws  162 ,  164 , such as during shipping and during use by the surgeon. Referring to  FIGS. 14D and 14E , one or more flexible bars  172  are provided between opposing handles  174   a ,  174   b  of crimp tool  160 . These bars  172  retain the jaws  162 ,  164  at predetermined positions to hold the stop member  60  in place during packaging, shipping and storage, but prevent jaws  162 ,  164  from coming together during application of relatively light loads which might otherwise prematurely collapse the stop member  60 . During use by the surgeon, however, the flexible bar or bars  172  do not prevent manual actuation of the handles  174   a ,  174   b  to bring the jaws  162 ,  164  together to collapse the stop member  60  as shown in  FIG. 14E . 
       FIGS. 16 and 17  illustrate an exemplary removal tool  180  which, in certain cases, may be necessary to remove an anchor assembly  10 . Specifically, removal tool  180  is in the general form of a rotatable hand tool, generally similar to a screwdriver, having a handle  179  and shaft  181 , which may be flexible. As best shown in  FIG. 17 , tool  180  further includes a head portion  182  having a needle  184  extending from a drive portion  186 . Needle  184  extends through the central bore  34  of anchor assembly  10  and drive portion  186  engages slot  32  of anchor assembly  10  in a manner similar to a screwdriver to thereby allow rotation of anchor assembly  10 . In the configuration shown, counterclockwise rotation of tool  180  and anchor assembly  10  will back the anchor assembly  10  out of a tendon or ligament  100 , for example, if the anchor assembly  10  is malpositioned. 
     Referring to  FIGS. 18A-18E , an exemplary method for repairing a tendon or ligament which has been cut or severed will now be described. This method is particularly useful because the anchor assembly is inserted into the severed end. In surgery, it is frequently advantageous to approach the repair site in this manner. In  FIG. 18A , an elongate tensile member  116 , such as a multi-filament suture, is inserted into the severed end  112   a  of a first tendon segment  100   a . The elongate tensile member  116  has a needle  190 , attached to the distal end which is inserted into the tendon segment  100   a , to facilitate insertion of the elongate tensile member  116  into the tendon segment  100   a . Alternatively, the end of elongate tensile member  116  may be sharpened to facilitate insertion into the tendon or ligament segment  100   a . A crimpable stop member  60  is also provided on the elongate tensile member  116  adjacent the needle  190  so that the crimpable stop member  60  is inserted into the tendon segment  100   a  with the needle  190 . Alternatively, the stop member  60  may be provided pre-clamped to the elongate tensile member  116 , or it may be applied to the elongate tensile member  116  for crimping by the surgeon after an end of the elongate tensile member  116  has been extended outside of the tendon segment  100   a . Soft tissue anchor  10  is coupled to the elongate tensile member  116  and is inserted into the severed end  112   a  of the first tendon segment  100   a  using, for example, insertion tool  70 . 
     Referring to  FIG. 18B , soft tissue anchor  10  is driven into tendon segment  100   a  to grip fibers  114  of the tendon segment. The needle  190  and elongate tensile member  116  are directed along the tendon segment  100   a  and then outside of a longitudinal sidewall of the tendon segment  100   a  so that the end of the elongate tensile member  116  extends beyond the sidewall of the tendon segment  100   a , as depicted in  FIG. 18B . The needle  190  is removed by cutting the elongate tensile member  116  using a cutting tool  154  and the stop member  60  may then be crimped to the elongate tensile member  116  using a tool, such as crimp tool  160  previously described. Tension is then applied to the elongate tensile member  116  to draw the extended portion of the elongate tensile member  116  and the stop member  60  back within the tendon segment  100   a  and to seat the stop member  60  against the soft tissue anchor  10 , as shown in  FIG. 18C . 
     A second soft tissue anchor  10  is coupled to the elongate tensile member  116  and the opposite end of the elongate tensile member  116  is inserted into a second tendon segment  100   b , following the procedure described above, as depicted in  FIG. 18D . After the second needle  190  has been removed, tension is applied to the elongate tensile member  116  while urging a second stop member  60  along the elongate tensile member  116  to seat against the second tissue anchor  10 . Tension is continued to be applied to the elongate tensile member  116  while applying force to the stop member  60  and second tissue anchor  10  to approximate the tendon segments  100   a ,  100   b , as shown in  FIG. 18E , using for example, crimp tool  160 , as previously described with respect to  FIGS. 14D and 14E . After the tendon segments  100   a ,  100   b  have been approximated and stop member  60  has been crimped, the elongate tensile member  116  may be cut using a cutting tool  154  and sutures may be applied as was described with respect to  FIGS. 14F and 14G . 
     While the method for repairing a tendon or ligament has been described above with respect to using one soft tissue anchor  10  in each segment of the tendon or ligament, it will be recognized that two or more soft tissue anchors may be used in each segment, as may be desired, to repair a tendon or ligament. 
     Referring to  FIGS. 19 and 20A , there is shown an exemplary tool  200  for installing a soft tissue anchor into a tendon or ligament and driving a needle and elongate tensile member into the tendon or ligament. The tool  200  includes an elongate tubular housing  202  having a first end  204  and a second end  206 . The first end  204  of the housing  202  is configured to receive a soft tissue anchor  10  and a handle  208  is provided at the second end  206 . As shown in  FIG. 20A , a tubular shaft  210  is disposed within the housing  202  and is coupled with a first knob  218  ( FIG. 19 ) provided on handle  208  at an end opposite the housing  202 . Shaft  210  extends through the housing  202  to the first end  204  and is coupled to a drive head  212  having a projecting portion  214  near the first end  204  of the housing  202 . The projecting portion  214  is configured to engage the drive slot  32  on a soft tissue anchor  10  and first knob  218  may be manipulated to rotate the shaft  210  while advancing the shaft  210  to extend beyond the first end  204  of the housing  202  in a manner similar to the operation of the anchor insertion tool  70  described above. Accordingly, the soft tissue anchor  10  received in the first end  204  of the housing  202  is driven into a tendon or ligament by the drive head  212  when the first knob  218  is manipulated. 
     The tool  200  further includes a tubular inner member  216  disposed concentrically within the shaft  210  and having an inner channel sized to receive an elongate tensile member  116  such as a multi-filament suture. The tubular inner member  216  is coupled at one end to a second knob  220  located on handle  208  adjacent first knob  218  (see  FIG. 19 ). When the second knob  220  is manipulated, either by rotation or, alternatively, by axial movement, the inner member  216  is advanced along the inner bore  222  of the tubular shaft  210  to extend beyond the first end  204  of the housing  202 . Advantageously, when an elongate tensile member  116  disposed within the tubular inner member  216  is provided with a needle  190 , the tubular inner member  216  may be used to advance the needle  190  and elongate tensile member  116  into a tendon or ligament as the second knob  220  is manipulated to advance the inner member  216 . Referring to  FIG. 20E , there is shown an alternative exemplary embodiment of tool  200 , wherein housing  202   a  is configured to include anti-rotation structure for preventing the tendon  100  from rotating with anchor assembly  10  during installation of the anchor assembly. In the embodiment shown, the anti-rotation structure includes spikes  224  which flare outwardly into a tendon from the first end  204  of housing  202   a  when extended from a retracted position within housing  202   a , as disclosed in PCT application PCT/US99/24098, filed Oct. 18, 1999 and herein incorporated by reference in its entirety. 
       FIGS. 20B-20D  illustrate operation of tool  200  to insert a soft tissue anchor assembly  10  within a tendon or ligament  100  and to advance an elongate tensile member  116  into the tendon  100 . In  FIG. 20B , the first end  204  of the housing  202  has been inserted through an incision in the tendon  100  and the first knob  218  has been manipulated to rotate and advance the shaft  210  along the housing  202  so that the anchor assembly  10  is advanced from within the first end  204  of the housing  202  and into the interior of the tendon  100 . As the soft tissue anchor assembly  10  moves forward into the tendon  100  while rotating, the fibers  114  of the tendon  100  are captured between the coils  13  of the helical anchor  12  and the retaining member  14 , as previously described. 
     In  FIG. 20C , the needle  190  and elongate tensile member  116  are advanced beyond the first end  204  of the housing  202  and through the tendon  100 , being urged by the inner member  216  which is advanced by manipulation of the second knob  220 . The needle  190  and elongate tensile member  116  are extended by the inner member  216  until they protrude from the severed end  112  of the tendon  100 . Once the needle  190  and elongate tensile member  116  have protruded through the severed end  112  of the tendon  100 , the housing  202  of tool  200  is withdrawn from the tendon  100  through the incision, leaving the soft tissue anchor assembly  10  embedded in the tendon  100  and coupled to the elongate tensile member  116 , as depicted in  FIG. 20D . A stop member  60  may then be coupled to the elongate tensile member  116  and the elongate tensile member  116  pulled to seat the stop member  60  against the soft tissue anchor assembly  10 , similar to the process described above for  FIGS. 18B and 18C . 
     Referring to FIGS.  21  and  22 A- 22 C, an exemplary tool  230  for crimping a crimpable stop member  60  and cutting an elongate tensile member  116  will now be described. The crimp-and-cut tool  230 , shown in  FIG. 21 , includes an elongate housing member  232  having a first end  234  and a second end  236 . The first end  234  of the tool  230  has a crimp jaw  238  for receiving a crimpable stop member  60  therein. An aperture  239  adjacent crimp jaw  238  permits the elongate tensile member  116 , to which the stop member  60  will be secured, to pass through the housing  232  and holds the elongate tensile member  116  for cutting. A handle  240 , which may include a thumb brace  242 , is provided at the second end  236  of the housing  232 . Tool  230  further includes a crimp bit  244 , having a crimping edge  246 , and a cutting member  248 , having a cutting edge  250 , disposed proximate the first end  234  of the housing  232 . The crimp bit  244  and cutting member  248  are moveable with respect to the housing  232  to engage stop member  60  and elongate tensile member  116 , respectively, retained in the crimp jaw  238  and aperture  239 . 
     An actuating structure  252 , shown in this exemplary embodiment in the form of a lever  252 , is pivotally attached by a pin  254  near the second end  236  of the housing  232 . The lever  252  is coupled to the crimp bit  244  and the cutting member  248 , whereby rotation of the lever  252  toward the handle  240  moves the crimp bit  244  and cutting member  248  in a direction toward the crimp jaw  238  and aperture  239  so that stop member  60  is crimped by the crimp bit  244  and elongate tensile member  116  is then cut by cutting member  248  after stop member  60  has been crimped. A biasing member  253  between the handle  240  and the actuating lever  252  keeps the lever  252  in a position relative to the handle  240  whereby the crimping edge  246  and cutting edge  250  of the tool  230  are maintained at a desired position with respect to a stop member  60  retained in crimp jaw  238 . While the actuating structure of crimp-and-cut tool  230  has been depicted and described as a pivotable lever  252 , the actuating structure may have other configurations, such as a sliding lever, a gear train, a push button, or any other structure suitable to initiate movement of crimp bit  244  and cutting member  248  for crimping stop member  60  and cutting elongate tensile member  116 . 
     In the exemplary embodiment shown, the actuating lever  252  is coupled to the crimp bit  244  by a crimp bit engagement arm  256  and to the cutting member  248  by a cutting member engagement arm  258 . The tool  230  may further include a spring element  245  disposed between crimp bit  244  and crimp bit engagement arm  256  to bias crimp bit  244  toward first end  234  and thereby hold a stop member  60  in jaw  238  without crimping the stop member  60 . In an exemplary embodiment, the biasing member  253  maintains the crimp bit engagement arm  256  at a position where crimping edge  246  abuts the stop member  60 , while spring element  245  provides a pressure sufficient to retain the stop member  60  in the crimp jaw  238  without crimping the stop member  60 . Biasing member  253  also helps to prevent premature actuation of actuating lever  252  to crimp stop member  60 . In the exemplary embodiment depicted in  FIG. 21 , engagement of biasing member  253  with protrusion  251  on actuating lever  252  creates a threshold force which must be overcome to cause a free end  255  of biasing member  253  to move over the protrusion so that actuating lever  252  can be pivoted about pin  254  toward handle  240 . 
     Operation of the exemplary cut-and-crimp tool  230  to crimp a stop member  60  and simultaneously cut an elongate tensile member  116  will now be described with respect to  FIGS. 22A-22C . Referring to  FIGS. 22A-22B , a crimpable stop member  60  is installed into the crimp jaw  238  of the tool  230  and elongate tensile member  116  coupled to the stop member  60  extends through aperture  239  in the housing  232 . In  FIG. 22B , actuating lever  252  is shown in an extended position, away from the handle  240 , whereby the crimping edge  246  of crimp bit  244  abuts stop member  60  and cutting member  248  is spaced from the elongate tensile member  116 . Spring element  245  urges crimp bit  244  toward first end  234  with a force sufficient to retain stop member  60  in jaw  238 . 
     In  FIG. 22C , the actuating lever  252  has been pivoted about pin  254 , in a direction toward the handle  240 , whereby first and second cam surfaces  257 ,  259  located at a driving end  260  of the actuating lever  252  urge the crimp bit engagement arm  256  and the cutting member engagement arm  258 , respectively, in a direction toward the first end  234  of housing  232 . As the crimp bit engagement arm  256  and the cutting member engagement arm  258  are moved forward, the crimp bit  244  and cutting member  248  are forced into engagement with the stop member  60  and elongate tensile member  116 , respectively, whereby the crimping edge  246  of the crimp bit  244  crimps the stop member  60  and the cutting edge  250  of cutting member  248  severs the elongate tensile member  116  adjacent the stop member  60 . In an exemplary embodiment, the cam surfaces  257 ,  259  on driving end  260  are configured such that crimp bit  244  crimps stop member  60  immediately before cutting edge  250  cuts elongate tensile member  116 . Advantageously, the first end  234  of the housing  232  may be inserted within a tendon or ligament to facilitate the crimping of a stop member  60  and cutting of an elongate tensile member  116  during the repair of a tendon or ligament. 
       FIGS. 23A-23F  depict an alternative embodiment of the exemplary crimp-and-cut tool  230   a , similar to the crimp-and-cut tool  230  of  FIGS. 21 and 22 , but having an alternate tip configuration proximate first end  234 .  FIGS. 23A-23E  further illustrate a stop member loading device  261 , which may be used to load stop members  60  into the crimp jaw  238  of the crimp-and-cut tool  230 ,  230   a . Loading tool  261  includes an elongate handle  262  with first and second pins  263 ,  264  positioned on a proximal end  265  of the handle  262 , as best depicted in  FIG. 23C . The first pin  263  is configured to receive a stop member  60  and the second pin  264  is configured to engage a recess  266  in the crimp bit  244  whereby the proximal end  265  of the loading tool  261  may be coupled with the first end  234  of the crimp-and-cut tool  230 ,  230   a  to move crimp bit  244  away from crimp jaw  238  and insert stop member  60  into the crimp jaw  238 . Specifically, the second pin  264  is inserted into the recess  266  in the crimp bit  244  through an aperture  267  in a cap plate  268  located near the first end  234  of housing  232 , as illustrated in  FIG. 23D . With the second pin  264  inserted within the recess  266 , the loading tool  261  may be used to slide the crimp bit  244  in a direction toward the second end  236 , against the bias force created by spring member  245 , thereby moving the crimping edge  246  away from the crimp jaw  238  so that stop member  60  positioned on first pin  263  may be placed within the crimp jaw  238 , as shown in  FIG. 23D . After stop member  60  has been inserted within crimp jaw  238 , handle  262  may be rotated in the direction of the arrow in  FIG. 23D , such that second pin  264  is withdrawn from recess  266  in the crimp bit  244  whereby crimp bit  244  is urged toward the first end  234  of housing  232  under the action of the spring member  245  to engage stop member  60  with a pressure sufficient to retain the stop member  60  between the crimp jaw  238  and the crimping edge  246 , as illustrated in  FIG. 23E . When it is desired to crimp the stop member  60  on an elongate tensile member  116  which has been coupled with stop member  60 , the first end  234  of crimp-and-cut tool  230 ,  230   a  may be positioned proximate a tendon repair location and the actuating lever  252  moved in a direction toward handle  240  to crimp the stop member  60  and severe the elongate tensile member  116 , as illustrated in  FIG. 23F  and described in detail above. 
       FIG. 23G  depicts another exemplary loading tool  261   a , similar to loading tool  261  of  FIG. 23A , but further including a downwardly extending arm  269  located at the proximal end  265  adjacent first pin  263 . Arm  269  is configured to register against the first end  234  of the crimp-and-cut tool  230 ,  230   a  to facilitate installation of stop member  60  into crimp jaw  238 . 
     With reference to  FIGS. 24A-24D , there is shown another exemplary soft tissue anchor assembly  270  of the present invention, described in conjunction with a method of inserting the soft tissue anchor assembly  270  within a tendon or ligament  100 . As best shown in  FIG. 24B , the exemplary soft tissue anchor assembly  270  comprises a helical coil anchor  272  and an expandable retaining member  274 . The retaining member  274  may be expanded from a first state (see  FIGS. 24A ,  24 B) wherein the outer surface of the retaining member  274  is spaced from the interior of the helical anchor  272  to a second, expanded state (see  FIGS. 24C-24E ) wherein the outer surface of the expandable retaining member  274  engages the interior of the helical anchor  272 . Advantageously, the anchor assembly  270  may be inserted within a ligament or tendon  100  whereby the fibers  114  of the ligament or tendon  100  may be captured between helical anchor  272  and the contracted retaining member  274 , whereafter, upon expansion of the retaining member  274 , the fibers  114  will be captured and held between the helical anchor  272  and the expanded retaining member  274 .  FIG. 24E  illustrates the retaining member  274  expanded against helical anchor  272  to capture fibers  114  therebetween. 
     With further reference to  FIGS. 24A-24D , a method of installing the anchor assembly  270  will now be described. In  FIG. 24A , the anchor assembly  270  is coupled to an elongate tensile member  116 , having a needle  190  coupled to its leading end, and is inserted into the severed end  112  of a ligament or tendon  100  using an appropriate insertion tool  273 , similar to those previously described. As the tissue anchor  270  is inserted within the tendon  100 , fibers  114  of the tendon  100  are gathered between the helical coil  272  and the contracted retaining member  274  as the helical coil  272  is rotated and advanced into the tendon  100 . In  FIG. 24B , the insertion tool  273  is removed and an expansion actuator  276 , such as a hollow tube installed over elongate tensile member  116 , is positioned proximate the anchor assembly  270 . 
     In  FIG. 24C , the expansion actuator  276  is placed into engagement with the retaining member  274  to expand the retaining member  274  and thereby capture fibers  114  as described above. Specifically, the actuator  276  is moved along the elongate tensile member  116  in the direction of arrow  277  while tension is applied to the elongate tensile member  116  in the direction of arrow  278  to compress the retaining member  274  between the needle  190  and the actuator  276  and thereby expand the retaining member  274 . After the retaining member  274  has been expanded, the actuator  276  may be removed from the elongate tensile member  116  as depicted in  FIG. 24D . The opposite end of the elongate tensile member  116  may then be attached to another tendon or ligament segment using methods, for example, similar to those previously described, or to a bone  280  using a bone anchor  282 , as depicted in  FIG. 24F . 
     With reference to  FIGS. 25-26 , methods for repairing a torn Achilles tendon using exemplary anchor assemblies of the present invention will now be described. Referring to  FIG. 25A , there is shown an Achilles tendon which has been severed such that a first tendon segment  100   a , attached to the calcaneus, or heel bone,  286  has separated from a second tendon segment  100   b  which is connected to the gastrocnemius (not shown) of the calf muscle. In one exemplary method, the severed tendon segments  100   a ,  100   b  may be repaired by inserting first and second soft tissue anchor assemblies  10  within the first segment of the tendon  100   a  through incisions  110   a  which have been made in the surface of the tendon segment  100   a  and installing third and fourth soft tissue anchor assemblies  10  into the second tendon segment  100   b  through corresponding incisions  110   b . Soft tissue anchor assemblies  10  may be inserted into the respective tendon segments  100   a ,  100   b  using, for example, any of the installation tools and methods previously described. If the tissue anchors  10  are installed using insertion tool  70 , then elongate tensile members  116  may be subsequently coupled to the tissue anchors  10 , such as by the method previously described with respect to  FIGS. 14A-14E . If insertion tool  200  is used to install at least some of the anchor assemblies  10 , these anchor assemblies will be installed with elongate tensile members  116  already coupled to them and the elongate tensile members  116  need only be coupled to corresponding anchor assemblies  10  in the other tendon segment, such as by the method described above with respect to  FIGS. 14A-14E . 
     In the exemplary method illustrated in  FIGS. 25A-25B , two elongate tensile members  116   a ,  116   b  are coupled to anchor assemblies  10  and are inserted within tendon segments  100   a ,  100   b . First and second stop members  60   a ,  60   b  may be provided pre-secured to elongate tensile members  116   a ,  116   b  or they may be coupled to the elongate tensile members  116   a ,  116   b  after installation of the elongate tensile members, as previously described. After the anchor assemblies  10  and elongate tensile members  116  have been installed within the respective tendon segments  100   a ,  100   b , the first and second elongate tensile members  116   a ,  116   b  may be tensioned to approximate the severed ends  112   a ,  112   b  of the tendon segments  100   a ,  100   b  as shown in  FIG. 25B . After the tendon segments  100   a ,  100   b  have been approximated, third and fourth stop members  60   a ,  60   b  are coupled to the elongate tensile members  116   a ,  116   b  and secured to the elongate tensile members  116   a ,  116   b  using, for example, crimp tool  160  or crimp-and-cut tool  230 , as previously described. 
     In another exemplary method, the corresponding soft tissue anchor assemblies  10  in the respective tendon segments  100   a ,  100   b  may be joined using a single elongate tensile member  116  looped through each of the anchor assemblies  10 , as depicted in  FIG. 26A . When the tendon segments  100   a ,  100   b  are attached using this method, the elongate tensile member  116  may be provided with a stop member  60  pre-secured to an end of the elongate tensile member  116 , or the stop member  60  may be secured to the elongate tensile member  116  in situ using either crimp tool  160  or crimp-and-cut tool  230 . After the elongate tensile member  116  has been coupled to each of the anchor assemblies  10 , tension is applied to the elongate tensile member  116  to approximate the severed ends  112   a ,  112   b  of the tendon segments  100   a ,  100   b , as depicted in  FIG. 26B . A second stop member  60  may then be secured to the elongate tensile member  116  and the excess portion of the elongate tensile member  116  trimmed using a cutting tool  154 . Alternatively, crimp-and-cut tool  230  may be used to secure the second stop member  60  and to cut the elongate tensile member  116 . 
     While  FIGS. 25 and 26  have depicted methods for repairing an Achilles tendon through incisions which have been made on the lateral sides of tendon segments  100   a ,  100   b , it will be recognized that the soft tissue anchor assemblies  10  and elongate tensile members  116  may alternatively be inserted through the severed ends  112   a ,  112   b  of the tendon segments  100   a ,  100   b  as described above with respect to  FIGS. 18A-18E . Furthermore, while the methods described above have utilized four soft tissue anchors  10 , it will be recognized that a greater number or a fewer number of soft tissue anchors  10  may be used to repair an Achilles tendon, as may be desired. 
     The foregoing methods have focused on tendon repair between severed segments of a tendon or ligament, however, it is sometimes desired to reattach a tendon or ligament to a bone, such as during the repair of a rotator cuff. Accordingly,  FIGS. 27-29  illustrate exemplary methods of attaching a ligament or tendon  100  to the humerus bone  290  during a rotator cuff repair. To attach a tendon or ligament  100  to the humerus  290  using elongate tensile members  116  and soft tissue anchor assemblies  10 , the elongate tensile members  116  must be secured to the head  292  of the humerus  290 . In one exemplary method, the surface of the humeral head  292  is prepared, such as by abrading the surface or forming a trough  294 , using a bone burr for example, and holes  296  are drilled through a segment of the humeral head  292 , as depicted in  FIG. 27A . 
     With continued reference to  FIG. 27A , first, second, third and fourth soft tissue anchor assemblies  10  are inserted within the tendon or ligament  100 , such as through incisions  110  formed in a surface of the tendon  100  and using an installation tool such as those previously described. Elongate tensile members  116  may either be coupled to at least some of the anchor assemblies  10  prior to installation and driven by an installation tool through the tendon  100 , or elongate tensile members  116  may be coupled to the tissue anchors after installation of the anchor assemblies  10 , as previously described. In the exemplary embodiment depicted in  FIG. 27A , two elongate tensile members  116   a ,  116   b  are used to secure the tendon  100  to the humeral head  292  whereby each elongate tensile member  116   a ,  116   b  is coupled to two of the anchor assemblies  10 , near the ends of the elongate tensile members  116   a ,  116   b , and intermediate portions of the elongate tensile members  116   a ,  116   b  are routed through the holes  296  in the humeral head  292 . The elongate tensile members  116   a ,  116   b  are tensioned to approximate the tendon  100  to the humeral head  292  such that the severed end  112  of the tendon  100  seats in the trough  294 , as depicted in  FIG. 27B . Stop members  60  are then secured to the free ends of elongate tensile members  116   a ,  116   b , as previously described. 
       FIGS. 28A and 28B  depict methods of securing a rotator cuff tendon  100  wherein the elongate tensile members  116  are secured to the humeral head  292  using stop members  60  and load distributing members, such as washers  298 . Referring to  FIG. 28A , two holes  296  are formed through a segment of the humeral head  292  and two soft tissue anchor assemblies  10  are inserted within the tendon  100  similar to the method described above for  FIG. 27A . An elongate tensile member  116  is routed through each of the anchor assemblies  10  and through the holes  296  such that tension applied to the elongate tensile members  116  approximates the tendon  100  to the humeral head  292 . Washers  298  are coupled to each of the elongate tensile members  116  and are secured to the elongate tensile members  116  using stop members  60 . While the load distributing members have been illustrated and described as flat washers  298 , it will be recognized that other types of load distributing members may also be used, such as Belleville washers. 
     In  FIG. 28B , another exemplary method of securing the rotator cuff tendon  100  to the humeral head  292  comprises installing first and second soft tissue anchor assemblies  10  within the tendon  100  such that the longitudinal axes of the anchor assemblies  10  are aligned substantially transverse to the longitudinal direction of the tendon  100 . A single elongate tensile member  116  is inserted within the tendon  100  and routed through both anchor assemblies  10 . The ends of the elongate tensile member  116  extend from the tendon  100  and are routed through the holes  296  and secured by washers  298  and stop members  60 , as described above with respect to  FIG. 28A . 
       FIGS. 29A-29B  illustrate another exemplary method of securing a rotator cuff tendon  100  to the humeral head  292  wherein a bone anchor  282  is installed proximate the desired attachment site, as depicted in  FIG. 29A . The surface of the humeral head  292  may be prepared at the attachment site, such as by abrading the surface or forming a trough  294 , as previously described. According to this method, one or more soft tissue anchor assemblies  10  are installed within the tendon  100  and at least one elongate tensile member is coupled between the bone anchor  282  and the soft tissue anchor assemblies  10 . Tension is applied to the elongate tensile member  116  to approximate the tendon  100  to the attachment site and stop members  60  are secured to the elongate tensile member  116  to fix the position of the tendon  100  proximate the attachment site, as depicted in  FIG. 29B . While the foregoing methods of securing a rotator cuff tendon  100  to the humeral head  292  have been described with respect to  FIGS. 27-29  as utilizing specific quantities of soft tissue anchor assemblies  10 , elongate tensile members  116 , bone anchors  282 , and other implantable devices, it will be recognized that the quantities of these implantable devices may be varied, as may be desired, to secure the tendon  100  to the humeral head  292 , in the general manner described herein, without departing from the present invention. 
     Referring to  FIGS. 30-32 , methods and apparatus for securing soft tissue to bones using bone anchors will now be described. In  FIG. 30A  there is shown an exemplary bone anchor  300  of the present invention. The bone anchor  300  is configured to be secured within a hole  301  which has been formed in a bone  280 . The bone anchor  300  has a generally cylindrically-shaped body  302  with a tapered first end  304  and a second end  305  having a flared aperture  306 . A central bore  303  extends along the body  302  between the tapered end  304  and the flared aperture  306 . The bore  303  is sized to receive an elongate tensile member  116 , such as a multi-filament suture. The elongate tensile member  116  is secured near the tapered end  304  by a pointed tip  310  and extends through bore  303  to exit the anchor  300  through flared aperture  306 . One or more lateral projections  308  extend outwardly from the body  302  and in a direction toward the flared aperture  306 . The lateral projections  308  are configured to engage the cancellous bone after the anchor  300  has been inserted into the hole  301  to thereby secure the anchor within the bone  280 . 
     Advantageously, the flared aperture  306  permits a tendon  100  to be secured substantially perpendicular to the longitudinal axis of the bone anchor  300  using an elongate tensile member  116 , while protecting the elongate tensile member  116  from exposure to sharp corners which may damage the elongate tensile member  116 . As further depicted in  FIG. 30A , the elongate tensile member  116  may be secured at an opposite end to a tendon  100  using a soft tissue anchor, such as anchor assembly  10 , or any of the soft tissue anchors described herein, and a stop member  60 , as previously described. 
       FIG. 30B  depicts another exemplary bone anchor  300   a , similar to bone anchor  300  of  FIG. 30A , but further including a flange  311  at second end  305  and extending radially outward from flared aperture  306 . Advantageously, flange  311  helps to position bone anchor  300   a  at an appropriate depth within hole  301  formed into bone  280 . 
       FIG. 31  depicts another exemplary bone anchor  300   b , similar to the bone anchors  300   a ,  300   b  depicted in  FIGS. 30A and 30B , but having a swivel member  312  provided at the second end  305  of the anchor  300   b . The elongate tensile member  116  extends through a bore  314  in the swivel member  312 , whereby a tendon or ligament  100  may be attached substantially perpendicular to the longitudinal axis of the bone anchor  300   b  without damaging the elongate tensile member  116 . Specifically, swivel member  312  accommodates orientation of the elongate tensile member  116  between the bone anchor  300   b  and the tendon or ligament  100 , and may also permit movement of the tendon or ligament  100  without exposing elongate tensile member  116  to sharp edges. 
     Referring now to  FIGS. 32A and 32B , there is shown yet another exemplary bone anchor  316  of the present invention. Bone anchor  316  is similar to the bone anchors  300 ,  300   a ,  300   b  depicted in  FIGS. 30 and 31 . The anchor  316  has a generally cylindrically-shaped body  318  with a first end having a pointed tip  320 . Lateral projections  308  extend outwardly from the body  318  to engage the cancellous bone  280  after the anchor  316  has been inserted into a hole  301  in the bone  280 . A second end  305  of the bone anchor  316 , opposite the pointed tip  320 , includes a crimp member  322  having an aperture  324  sized to receive an elongate tensile member  116  therethrough. As depicted in  FIG. 32B , the crimp member  322  may be crimped to secure the elongate tensile member  116  within the aperture  324  after elongate tensile member has been tensioned to approximate the tendon or ligament  100  to a desired position adjacent the bone anchor  316 . 
       FIG. 32C  depicts another exemplary bone anchor  330  and a method for securing a tendon or ligament  100  to a bone  280 . In this embodiment, a bone anchor  330  includes lateral projections in the form of screw threads  332  disposed along a generally cylindrical body  334 . The bone anchor  330  further includes a projection  336  which preferably extends beyond the surface of the bone  280  and has an aperture  338  sized to receive an elongate tensile member  116  therethrough. After the elongate tensile member  116  has been tensioned to position the tendon or ligament  100  at a desired location adjacent the bone anchor  330 , a stop member  60  may be secured to the elongate tensile member  116  to attach the tendon or ligament  100 . The opposite end of the elongate tensile member is secured to the tendon or ligament  100  using a soft tissue anchor, such as anchor assembly  10 , or any of the soft tissue anchors described herein, and a stop member  60 , as previously described. 
       FIG. 32D  depicts yet another exemplary bone anchor  340  having a generally cylindrical body  342  and a pointed tip  344 . Lateral projections  308  extend outwardly from the cylindrical body  342  to engage the cancellous bone  280  as previously described. The anchor  340  further includes a projection  346  having an aperture  348  configured to receive elongate tensile member  350  that has a series of serrations  352  or other similarly contoured surface along its length, whereby engagement of the serrations  352  with the aperture  348  secures the elongate tensile member  350  to the bone anchor  340 . The opposite end of the elongate tensile member  352  may be secured to a tendon or ligament  100 , using a soft tissue anchor assembly  10 , or any other soft tissue anchor such as those described herein, and a stop member  60 , in a manner similar to that previously described with respect to elongate tensile member  116 . 
     While the projections are depicted in the figures as elongate members and screw threads, the projections may alternatively be barbs, screw threads, spikes, or other structure which is capable of engaging the bone  280  upon insertion into the hole  301 , or after insertion. 
     Referring to  FIG. 33 , there is shown another exemplary anchor  360  of the present invention which is configured to attach a soft tissue directly to a hard tissue. The anchor  360  has a first portion  362  figured to engage hard tissue, such as bone, and a second portion  364  configured to engage soft tissue. The first portion  362  includes an elongate shaft  366  having screw threads  368  disposed along its length and configured to bore into hard tissue to securely attach the anchor  360  within the hard tissue. Alternatively, a plurality of barbs (not shown) may be disposed along shaft  366  to permit secure attachment of the anchor  360  within the hard tissue. The second portion  364  of anchor  360  comprises a soft tissue anchor assembly similar to the anchor assembly  10  of  FIGS. 1 and 2 , wherein the second portion  364  includes a helical anchor  370  and a retaining member  372 . Second portion  364  further includes a slot  373  formed into proximal end  374  and configured to engage a drive tool, whereby the anchor  360  may be driven into hard tissue. Other features of the second portion  364  are similar to the anchor assembly  10  of  FIGS. 1 and 2 . As depicted in  FIG. 33 , the pitch P 1  of the first portion  362  of the anchor  360  is greater than the pitch P 2  of the second portion  364  to allow soft tissue engaged by the second portion  364  to be compressed while the anchor  360  is being screwed into hard tissue. 
       FIG. 34  depicts a top section view of a shoulder joint and illustrates an exemplary use of the anchor  360  to stabilize the shoulder. The anchor  360  is inserted into the scapula  380  near the glenoid socket  382  and through the glenoid labrum  384  to reattach the labrum  384  to near glenoid socket  382 . 
       FIGS. 35A-35C  illustrate another apparatus  390  which may be used to reattach the glenoid labrum  384  to the glenoid socket  382 . With reference to  FIG. 35A , the apparatus  390  includes a flexible cable  392  having a tip  394  which is adapted to bore through bone and tissue as the cable  392  is rotated about its longitudinal axis. Advantageously, the apparatus  390  may be used to install the cable  392  through the glenoid socket  382 , from a position inside the shoulder capsule, and subsequently through the glenoid labrum  384  as depicted in  FIG. 35B . Once the cable  392  has been extended through the glenoid labrum  384 , a soft tissue anchor, such as anchor assembly  10  or any other soft tissue anchor described herein, may be coupled to the cable  392  and inserted into the glenoid labrum  384  to be secured with a stop member  60  according to methods previously described. The opposite end of the cable  392  which extends through the glenoid socket  382  may be secured using a load distributing member, such as washer  396 , having a crimpable portion  396   a . Alternatively, a flat washer  298  and stop member  60  may be used to secure cable  392  in a manner similar to that depicted in  FIGS. 28A-28B . Other types of load distributing members may be used as well. 
     In an exemplary embodiment, cable  392  is configured to have elasticity in the longitudinal direction, whereby cable  392  may be tensioned to compress the glenoid labrum  384  against the glenoid socket  382  with a desired spring force. Alternatively, a relatively inextensible cable  392  may be coupled with a spring element, such as a Belleville washer  397 , to create a desired spring force, as depicted in  FIG. 35C . In this embodiment, Belleville washer  397  may be secured to the end of the cable  392  using, for example, a stop member  60 . 
     With reference to  FIGS. 36-46 , a method of reattaching a rotator cuff ligament  402  to the humeral head  292  of the humerus  290  will now be described. In preparation for repairing a torn rotator cuff, one or more cannulas  400   a ,  400   b ,  400   c  may be inserted into the shoulder of a patient near the humeral head  292  of the humerus bone  290 , as depicted in  FIG. 36 . While the method below is described with respect to using cannulas, it will be recognized that the attending surgeon may alternatively reattach the rotator duff ligament  402  through incisions at appropriate locations without using cannulas and in a manner similar to that herein described.  FIG. 36  also illustrates relevant anatomy of the patient, such as the scapula  380 , the acromium  381  and the glenoid labrum  384 . To reattach the rotator cuff tendon  402  to the humeral head  292 , a scalpel  404 , or any other cutting device, such as an electro-surgical cutting device, is inserted through a first cannula  400   a  and is used to make an incision, or tenotomy,  406  at a location where it is desired to install a soft tissue anchor. A bone anchor  408 , which may be a conventional bone anchor or any of the bone anchors described herein, is inserted through a second cannula  400   b  and is installed to a pre-drilled hole  412  using a bone anchor installation tool  410 . After the incision  406  has been made in the rotator cuff tendon  402 , a soft tissue anchor assembly may be installed within the tendon  402  using installation tool  200  inserted through the first cannula  400   a  as depicted in  FIG. 37 . As illustrated in  FIG. 38 , the attending surgeon manipulates first knob  218  of tool  200  to rotate the soft tissue anchor assembly (not shown) while advancing the anchor assembly into the tendon  402 , as was previously described with respect to  FIGS. 20A-20B . 
     After the soft tissue anchor assembly has been secured within the tendon  402 , the attending surgeon may then manipulate the second knob  220  of the installation tool  200  to advance an elongate tensile member  116 , such as a multi-filament suture, through the tendon  402  as illustrated in  FIG. 39  and previously described with respect to  FIG. 20C . Stop member  60  may be applied to the elongate tensile member  116  by the attending surgeon using, for example, the crimp-and-cut tool  230 , previously described above, as illustrated in  FIG. 40 . The elongate tensile member  116  is routed from the end of the tendon  402  to couple with the bone anchor  408  and is pulled out through the second cannula  400   b  using forceps  414  or any other appropriate tool as illustrated in  FIGS. 40 and 41 . 
     Once the elongate tensile member  116  has been routed through second cannula  400   b , it may then be drawn tight to approximate the tendon  402  to a desired location adjacent the bone anchor  408  and a second stop member  60  may be applied to the elongate tensile member  116  using, for example, the cut-and-crimp installation tool  230  as illustrated in  FIGS. 42 and 43 . As shown in  FIG. 43 , the tendon  402  is thus fixed to the humeral head  292  in a secure attachment which utilizes the natural strength of the collagen fibers of the tendon  402  while minimizing the amount of foreign material external to the tendon  402  at the repair site. 
     While elongate tensile member  116  may be coupled to anchor assembly  10  prior to installation of the tissue anchor  10  into the tendon  402  and subsequently routed through bone anchor  408  as described above with respect to  FIGS. 40 and 41 , elongate tensile member  116  may alternatively be routed through the soft tissue anchor  10  and bone anchor  408  using a shuttle suture  416  which has been coupled to the soft tissue anchor  10  and installed, for example, using installation tool  200  as previously described with respect to  FIGS. 37-39 . As illustrated in  FIG. 44A , shuttle suture  416  includes a needle tip  418  and a flexible suture member  420 . The shuttle suture  416  is configured to have a loop  422  through which one end of the elongate tensile member  116  may be inserted. After the shuttle suture  416  has been driven through tendon  402  and routed through bone anchor  408 , it is withdrawn through the second cannula  400   b  to shuttle the elongate tensile member  116  through the first cannula  400   a , the soft tissue anchor ( FIG. 41 ), the bone anchor  408  (see  FIG. 44B ), and the second cannula  400   b  using forceps  414 , as illustrated in  FIG. 45 . Alternatively, shuttle suture  416  may be routed in the opposite direction, entering through second cannula  400   b  and being withdrawn from first cannula  400   a , as depicted in  FIG. 46 . 
     While the foregoing methods have been described with regard to the installation of a single soft tissue anchor assembly  10  of the present invention, it will be recognized that more than one anchor assembly  10  may be installed into the tendon  402  to affect the repair. For example,  FIGS. 47A and 47B  illustrate two alternative configurations wherein two anchor assemblies  10  may be inserted into a tendon  402  and coupled to a single bone anchor  408 . In  FIG. 47A , each anchor assembly  10  is coupled to the bone anchor  408  using a separate elongate tensile member  116 . In  FIG. 47B , two anchor assemblies  10  are coupled to a bone anchor  408  using a common elongate tensile member  116 . In a similar fashion, it will be recognized that a single soft tissue anchor assembly  10  may be coupled to two or more bone anchors  408  to affect a tendon repair. Furthermore, it will be recognized that, in certain instances, the various steps of methods described herein may be performed in orders other than those described. Accordingly, the methods are not limited to being performed in any particular order of steps. 
     Referring now to  FIGS. 48 and 49 , there are shown exemplary soft tissue anchor assemblies similar to the anchor assembly  10  of  FIGS. 1 and 2 , wherein the anchor assemblies are further configured to be secured to an elongate tensile member and wherein like components are similarly numbered. In  FIG. 48 , there is shown an exemplary soft tissue anchor assembly  430  having a stop member  432  integral with the retaining member  146  and configured to engage a contoured surface of an elongate tensile member  434 , which may be coupled to the anchor assembly  430 . In the exemplary embodiment shown, the contour of elongate tensile member  434  includes a series of serrations  436  and integral stop member  432  is configured to engage the serrations  436  to securely fix the anchor assembly  430  to the elongate tensile member  434 . 
     In  FIG. 49 , there is shown an exemplary soft tissue anchor assembly  440  wherein the retaining member  14   c  includes an integral stop member  442  which is configured to be secured to an elongate tensile member  116  by crimping the integral stop member  442  in a manner similar to the crimping of stop members  60  previously described. 
     Referring to  FIG. 50 , there is shown yet another exemplary apparatus for repairing a tendon or ligament. The apparatus includes a soft tissue anchor assembly  10 , as depicted in  FIGS. 1 and 2 , and a stop member  450  which may be secured to a contoured surface of an elongate tensile member  434 . In the exemplary embodiment shown, the stop member  450  is similar to the stop member  60  previously described, and further includes an integral engagement member  454  configured to engage serrations  436  in the elongate tensile member  434  to thereby secure the stop member  450  to the elongate tensile member  434 . 
     Referring now to  FIG. 51 , there is shown an exemplary anchor assembly  460  for attaching soft tissue to bone. The anchor assembly  460  is similar to the anchor assembly  360  of  FIG. 33  and includes first and second portions which may be coupled together to form the anchor assembly  460 . The first portion  462  includes an elongate shaft  468  having an enlarged head  464  at one end and bone engaging structure  470  at an opposite end. The enlarged head  464  includes a slot  466  for receiving a drive tool which facilitates installation of the anchor assembly  460 . In the exemplary embodiment shown, the bone engaging structure  470  includes screw threads  472 , but may alternatively include other structure for engaging the bone, such as barbs (not shown) extending outwardly from the shaft  468 . The second portion of the anchor assembly  460  comprises a soft tissue anchor  10 , previously described with respect to  FIGS. 1 and 2 . As shown in  FIG. 51 , the first portion  462  may be coupled to the anchor assembly  10  such as through bore  34  in anchor assembly  10 . Advantageously, the anchor assembly  460  may be used to secure soft tissue to a bone in a manner similar to that described for anchor assembly  360  of  FIG. 33 . 
       FIGS. 52A-52C  illustrate another apparatus for securing soft tissue to a bone. As shown in  FIG. 52A , the apparatus includes a bone anchor  480  which may be inserted into a cavity, such as a drilled hole  301 , formed in a bone  280 . The bone anchor assembly  480  includes a collapsible member  482  which is configured to expand in a direction substantially normal to a lengthwise direction of the member to thereby securely engage the anchor assembly  480  to the bone  280 . In the embodiments illustrated in  FIGS. 52A and 52B , the collapsible member  482  is made up of one or more buckling elements which extend outwardly to engage the bone  280  as the anchor assembly  480  is collapsed along its lengthwise direction. The apparatus further includes an elongate tensile member  116  coupled to the bone anchor assembly  480  such as by an end member  484  integral with said collapsible member  482 . Alternatively, end member  484  may be secured to elongate tensile member  116  to abut collapsible member  482  as tension is applied to elongate tensile member  116 . To facilitate expanding collapsible member  482 , an actuating member, such as a tube  486  installed over elongate tensile member  116 , may be inserted through the soft tissue  481  to abut the anchor assembly  480  while tension is applied to elongate tensile member  116  to collapse the collapsible member  482 . As illustrated in  FIG. 52C , the elongate tensile member may be secured to the soft tissue  481  using, for example, a soft tissue anchor  10  and a stop member  60 , as previously described. 
     With reference to FIGS.  53  and  54 A- 54 C, there is shown another exemplary soft tissue anchor assembly  490  similar to the anchor assembly  10  of  FIGS. 1 and 2 , and including an expandable retaining member  492 . The retaining member  492  is coupled to a helical anchor  12  in the manner previously described, whereby the retaining member and helical anchor may be simultaneously driven into a tendon or ligament to receive fibers of the tendon or ligament between the helical anchor  12  and the retaining member  492 . An expansion member  494  is configured to engage the retaining member  492  to thereby expand the retaining member to grip the fibers of the tendon or ligament between the helical anchor  12  and the retaining member  492 . In the exemplary embodiment shown, retaining member  492  includes one or more slots  496  formed longitudinally along the retaining member  492  to separate the retaining member  492  into outwardly expandable portions  497 . As shown most clearly in  FIGS. 54A and 54B , retaining member  492  further includes a bore  34  extending through the retaining member and sized to receive an elongate tensile member  116  therethrough. The retaining member  492  further includes an aperture  498  which is configured to receive expansion member  494 . 
     Aperture  498  has a tapered surface  500  which is configured to mate with a corresponding tapered surface  502  on the expansion member  494 , whereby the expandable portions  497  may be driven outward by the interaction between the tapered surfaces  500 ,  502  when expansion member  494  is urged into engagement with retaining member  492  as depicted in  FIG. 54B . In an exemplary embodiment, retaining member  492  further includes an annual detent disposed within aperture  498  and configured to engage a corresponding groove  506  formed into expansion member  494 . Advantageously, the annular detent  504  engages the groove  506  on the expansion member  494  to secure the expansion member  494  to the retaining member  492  after expandable portions  497  have been expanded outwardly against the helical anchor  12 . 
     Anchor assembly  490 , including expansion member  494 , may be secured to an elongate tensile member  116  using a stop member  60  in a manner such as previously described. Alternatively, the expansion member  494  may include a crimpable portion  508  that permits the anchor assembly  490  to be secured to an elongate tensile member  116 , as depicted in  FIGS. 54A and 54B . Alternatively, expansion member  494   a  may be provided pre-secured to an elongate tensile member  116  whereby the retaining member  492  may be expanded by applying tension to elongate tensile member  116  to urge expansion member  494   a  into engagement with expandable retaining member  492  to expand the expandable portions  497  as described above and as depicted in  FIG. 55 . 
     While the present invention has been illustrated by the description of the various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of Applicant&#39;s general inventive concept.