Patent Publication Number: US-10327755-B2

Title: Devices, systems, and methods for attaching soft tissue to bone tissue

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/124,344 filed Sep. 7, 2016, now U.S. Pat. No. 9,861,353, which application is a national stage entry of PCT Application No. PCT/US2015/016671 filed Feb. 19, 2015, which application claims priority to U.S. provisional patent application No. 62/093,827 filed Dec. 18, 2014 entitled “DEVICES, SYSTEMS, AND METHODS FOR ATTACHING SOFT TISSUE TO BONE TISSUE;” U.S. provisional patent application No. 62/000,379, which was filed May 19, 2014, entitled “DOUBLE-LOOPED SUTURE;” and U.S. provisional patent application 61/949,485, which was filed Mar. 7, 2014, entitled “DOUBLE-LOOPED SUTURE.” 
     This application is also a continuation of U.S. patent application Ser. No. 14/610,711 filed 30 Jan. 2015, which application is a continuation-in-part of PCT Application No. PCT/US2013/053524, with an international filing date of Aug. 3, 2013, entitled “SUTURE ANCHOR DEVICE AND METHODS OF USE.” PCT Application No. PCT/US2013/053524 claims priority to U.S. patent application Ser. No. 13/566,845 which was filed Aug. 3, 2012 and to U.S. provisional patent application 61/817,841 which was filed Apr. 30, 2013. 
     Each of the foregoing applications is hereby incorporated in its entirety into the present application. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to medical devices and to surgical implements. More particularly, preferred embodiments of the invention relate to suture anchor devices and methods for using the same. 
     BACKGROUND 
     Soft tissue, such as tendons or ligaments, is typically displaced from its usual position in relation to the bone due to injury such as rupturing or tearing. Rotator cuffs, elbows, knees, ankles, and other joints are particularly prone to this type of injury. Injuries can be treated by attaching the soft tissue to the bone. Attaching soft tissue to bone may make use of suture anchors. Generally, a bone anchor with pre-loaded sutures is deployed into bone by inserting the anchor into an opening drilled into the bone. The pre-loaded sutures are used to attach the soft tissue to the bone by suture fixation techniques such as knot-tying, or by insertion of the suture into a knotless anchor for fixation. 
     Surgical anchor repairs suffer risk of biomechanical failure. Reported failures include suture cutting through bone tunnels, suture breakage, knot slippage, suture anchor pull out, and soft tissue failure at the suture-tendon junction. There is a need for a suture anchor device and method of use that will lower the risk of such biomechanical failures. 
     SUMMARY OF THE INVENTION 
     In one aspect, a tissue anchor is provided that includes a body and a flexible elongated element. The body may include a proximal end, a distal end opposite the proximal end, a proximal opening at the proximal end, a distal opening at the distal end, and a passage extending longitudinally through the body between the proximal and distal openings. The flexible elongated element may at least contribute to the defining of an aperture that opens in a direction substantially perpendicular to a longitudinal axis of the passage. The flexible elongated element may be secured to the body at first and second spaced-apart locations to facilitate the aperture being maintained in an open condition. The first and second spaced-apart locations may include a first side of the passage and a second side of the passage opposite the first side of the passage. The flexible elongated element may be secured to the each side of the passage via a ring, hook or loop. The body may further include a distal tip that may be at least one of received or configured to be received in the distal opening. The first and second spaced-apart locations may include a first side of the distal tip and a second side of the distal tip opposite the first side of the distal tip. The body may further include a distal tip that may be at least one of received or configured to be received in the distal opening. The flexible elongated element may include a first tail and a second tail spaced-apart from the first tail by the first tail and the second tail respectively intersecting the distal tip at the first and second spaced-apart locations thereby facilitating the aperture being maintained in the open condition. When the distal tip is received in the distal opening, the aperture may be located in the passage proximal the distal tip. The distal tip may include a molded material; a distal region of the first tail and a distal region of the second tail may be molded into the molded material at the first and second spaced-apart locations. The distal tip may be configured such that implantation forces exerted on the distal tip may enhance the extent to which the distal tip may be received in the distal opening. The first and second spaced-apart locations respectively may include first and second spaced-apart channels in the distal tip, and a distal region of the first tail and a distal region of the second tail may be respectively located in the first and second spaced-apart channels. The first spaced-apart channel may include a groove defined in an outer surface of the distal tip and the distal region of the first tail may extend through the groove, which may open against an inner wall surface defining the passage when the distal tip is received in the distal opening. The first spaced-apart channel may include a lumen defined in the distal tip and the distal region of the first tail may extend through the lumen. The first and second tails may be distally joined together via a knot. The knot may be coated or impregnated with a polymer, epoxy or adhesive. The first and second tails may be part of a continuous loop of the flexible elongated element. The first and second tails may extend into each other in a continuous manner. The first and second tails may be distally joined together via a joining member extending about the at least portions of the first and second tails. The joining member may be at least one of crimped or molded onto the first and second tails. The distal tip may include a distal recess in which the joining member may be seated. The distal tip may include a proximal shaft opposite the distal recess, the distal tip being received in the distal opening on account of the proximal shaft being received in the distal opening and residing in the passage. The proximal shaft may form an interference fit with at least one of the distal opening or the passage. The first and second spaced-apart channels may extend longitudinally along the proximal shaft. The aperture may be defined between the flexible elongated element and a proximal end of the proximal shaft of the distal tip. A maximum height of the aperture in a non-deflected state and extending parallel to the longitudinal axis of the passage may be defined between the flexible elongated element and a proximal end of the distal tip. The maximum height of the aperture may be between a height of the proximal end of the tissue anchor and a height of the proximal end of the body plus a thickness of a soft tissue. The soft tissue may be proximal to the proximal end of the body. A maximum width of the aperture in a non-deflected state may be defined between the first and second spaced-apart locations, and the maximum width of the aperture may be approximately the maximum width of the passage. The maximum width of the aperture may extend perpendicular to the longitudinal axis of the passage. A most proximal extent of the flexible elongated element in a non-deflected state may be recessed distally within the passage from the proximal opening up to approximately a thickness of a suture mass to be passed through the aperture. The proximal opening may be configured to interface with an insertion tool. The flexible elongated element may include a suture. The suture may be a braided suture formed of a material that may include polyethylene. The material may further include a thickness of between approximately 0.008″ and approximately 0.045″. The suture may be at least one of heat treated, coated or impregnated to at least one of stiffen or shape the suture. The flexible elongated element may include a wire or monofilament. The flexible elongated element may extend through a sheath. The flexible elongated element may extend along a U-shaped channel member. A segment of polymer or metal may extend through a lumen of the flexible elongated element. A loop may encircle a portion of the distal tip and the loop may include the flexible elongated element. The aperture may be defined between the flexible elongated element and a proximal end of the distal tip. The loop may further include a joining member joining together the first and second tails of the flexible elongated element. The joining member may be received in a distal recess of the distal tip. 
     In this one aspect, the tissue anchor may be a result of an assembly process. The assembly process may include: a) assembling a tip assembly by causing a loop to encircle a portion of the distal tip; and b) causing the tip assembly to be received in the distal opening of the body. The loop may include the flexible elongated element. The loop may further include a joining member joining together the first and second tails of the flexible elongated element, and the joining member may be received in a distal recess of the distal tip as part of assembling the tip assembly. 
     In this one aspect, the body may further include a thread helically extending about an exterior of the body. The thread may include a double helix thread; the double helix thread may include two distinct threads offset approximately 180 degrees from each other. The aperture may have a minimum width to height ratio of three to one and a maximum width to height ratio of one to ten. The flexible elongated element may be configured to flex in a twisting rotation manner such that the aperture can accommodate different suture exchange attack angles. The flexible elongated element may be configured to flex in a twisting rotation manner such that a direction in which the aperture opens when the flexible elongated element is at maximum twisted rotation may be between approximately 90 degrees and approximately 360 degrees from the direction in which the aperture opens when the flexible elongated element is in a non-deflected state. The flexible elongated element may be configured to maintain the aperture sufficiently open to accommodate suture exchange despite being at the maximum twisted rotation. The flexible elongated element may be configured to flex in a twisting rotation manner such that the aperture has no angles that are tighter than approximately 90 degrees when the flexible elongated element is at a twisted rotation of up to approximately 90 degrees from the direction in which the aperture opens when the flexible elongated element is in a non-deflected state. The aperture may be configured to accommodate a minimum mass throughput of 4 sutures. 
     In another aspect, a surgical kit is provided that may include: the tissue anchor described herein, a suture, and instructions. The body of the tissue anchor may further include a distal tip that may be at least one of received or configured to be received in the distal opening. The flexible elongated element may include a first tail and a second tail spaced-apart from the first tail by the first tail and the second tail respectively intersecting the distal tip at the first and second spaced-apart locations thereby facilitating the aperture being maintained in the open condition. The suture may include a first end and a second end opposite the first end. The instructions may provide that, with the suture first extending through the aperture, the distal tip may be caused to be received in the distal opening such that the suture may extend through the passage and out the proximal opening such that the first and second ends of the suture are proximal the proximal opening. The suture may further include a loop at at least one of the first end or the second end of the suture. The loop may be the result of a bifurcation of the suture or the loop may be a result of the suture being folded back on itself and adhered to itself. 
     In this other aspect, the surgical kit may further include a delivery device. The delivery device may include a distal end, a proximal end opposite the distal end, and a lumen extending between the distal and proximal ends of the delivery device. The distal end of the delivery device may include a feature for coupling with and transmitting a torque to the proximal end of the body. The instructions may further provide that, once the distal tip is received in the distal opening such that the suture extends through the passage and out the proximal opening such that the first and second ends of the suture are proximal the proximal opening, the suture may be further caused to extend through the lumen such that the first and second ends of the suture extend from the proximal end of the delivery device and the distal end of the delivery device may be engaged with the proximal end of the body. The instructions may be provided via at least one of: on packaging enclosing at least some of the surgical kit; in packaging enclosing at least some of the surgical kit; accompanying the surgical kit; an electronic communication; or an internet website. 
     In another additional aspect, a method of anchoring soft tissue to bone via a first tissue anchor including a body including a proximal opening, a distal opening, a passage extending between the proximal and distal openings, and a distal tip configured to be received in the distal opening is provided. The distal tip may be loaded with a first suture such that the first suture extends through an aperture of the distal tip. In this other additional aspect, the method may include: causing the distal tip loaded with the first suture to be received in the distal opening of the body such that the first suture extends through the passage of the body and out the proximal opening such that the first and second ends of the first suture are proximal the proximal opening. Once the distal tip is received in the distal opening such that the first suture extends through the passage and out the proximal opening such that the first and second ends of the first suture are proximal the proximal opening, the first suture may be further caused to extend through a lumen of a delivery device such that the first and second ends of the first suture extend from a proximal end of the delivery device and a distal end of the delivery device is engaged with a proximal end of the body. The lumen may extend between a distal end of the delivery device and the proximal end of the delivery device. The method may further include using the delivery device to torque the first tissue anchor into the bone. The method may further include implanting the first tissue anchor into the bone with the suture loaded distal tip received in the distal opening. The method may further include: a) extending the first and second ends of the first suture through the soft tissue; b) after step a), causing a second suture to extend through a loop defined in the first suture near the first end of the first suture or between the first and second ends of the first suture; and c) after step b), pulling on the second end of the first suture to draw the second suture through the soft tissue and down into the implanted first tissue anchor and through the aperture such that the second suture extends through the passage of the body and out the proximal opening such that first and second ends of the second suture are proximal the proximal opening and extend through the soft tissue. The second suture may extend through the soft tissue from a second tissue anchor implanted in the bone prior to being caused to pass again through the soft tissue at another location and down into the first tissue anchor as recited in step c). The second suture at the completion of step c) may extend from the first end of the second suture through the soft tissue, into and out of the implanted second tissue anchor, through the soft tissue, back into the soft tissue, into and out of the implanted first tissue anchor, and through the soft tissue to the second end of the second suture. The method may further include: a) causing a second suture to extend through a loop defined in the first suture near the first end of the first suture or between the first and second ends of the first suture; b) after step a), pulling on the second end of the first suture to draw the second suture down into the implanted first tissue anchor and through the aperture such that the second suture extends through the passage of the body and out the proximal opening such that first and second ends of the second suture are proximal the proximal opening; and c) after step b) extending the first and second ends of the second suture through the soft tissue. The second suture may extend from a second tissue anchor implanted in the bone prior to being caused to pass down into the first tissue anchor as recited in step b). The second suture at the completion of step c) may extend from the first end of the second suture through the soft tissue, into and out of the implanted second tissue anchor, through the soft tissue, back into the soft tissue, into and out of the implanted first tissue anchor, and through the soft tissue to the second end of the second suture. 
     While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the disclosure. As will be realized, the invention is capable of modifications in various aspects, all without departing from the spirit and scope of the present disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The following figures describe various aspects of the disclosure. 
         FIG. 1  is a side view of a tissue anchor device. 
         FIG. 2  is a cross-sectional side view of a tissue anchor device. 
         FIG. 3  is a transparent side view of a tissue anchor device. 
         FIG. 4  is a top perspective view of a tissue anchor device. 
         FIG. 5  is a side view of a tissue anchor device with a suture exchange fitting at the proximal end of the body. 
         FIG. 6  is a perspective cutaway view of a single-piece tissue anchor device with a suture exchange fitting and sutures. 
         FIG. 7  is an exploded view of a tissue anchor device. 
         FIG. 8  is a cross-sectional side view of a tissue anchor device. 
         FIG. 9  is a side view of a tissue anchor device with a separate distal tip. 
         FIG. 10  is a side view of a suture exchange fitting in an opened configuration. 
         FIG. 11  is a side view of a suture exchange fitting in a collapsed configuration. 
         FIG. 12  is a side view of a distal end and a twisted exchange ring of a suture exchange fitting. 
         FIG. 13  is a top view of a distal end and a twisted exchange ring of a suture exchange fitting. 
         FIG. 14  is a side view of a distal end and a suture exchange fitting with a short exchange ring. 
         FIG. 15  is a side view of a distal end and a suture exchange fitting with a long exchange ring. 
         FIG. 16  is a side view of a suture exchange fitting in an opened configuration with several sutures within the exchange ring. 
         FIG. 17  is a cross-sectional side view of a tissue anchor device with support loops attached to the inner wall defining the passage. 
         FIG. 18  is a top perspective view of a distal tip with a first channel at a first side and a second channel at a second side of the distal tip. 
         FIG. 19  is a cross-sectional side view of a tissue anchor device with an exchange ring formed from a single flexible strand with opposed ends secured between the distal end of the body and the proximal end of the distal tip. 
         FIG. 20  is a top perspective view of a distal tip with an exchange ring formed from a single flexible strand with opposed ends attached to a proximal face of the distal tip. 
         FIG. 21  is a cross-sectional side view of a tissue anchor device with an exchange ring formed from a single flexible strand reinforced by a braided sheath. 
         FIG. 22  is a cross-sectional side view of a tissue anchor device with an exchange ring formed from a single flexible strand reinforced by a U-shaped reinforcing element. 
         FIG. 23  is a cross-sectional side view of a tissue anchor device with an exchange ring formed from a single flexible strand reinforced by an internal reinforcing element. 
         FIG. 24  is a side view of a U-shaped reinforcing element with a defect configured to enable the collapse of the exchange ring under a collapsing load. 
         FIG. 25  is a cross-sectional side view of a tissue anchor device with an exchange ring formed as a clip collapsed by an upward pull at greater than the collapsing force. 
         FIG. 26  is a cross-sectional side view of a tissue anchor device with an exchange ring formed as a clip collapsed by a downward push at greater than the collapsing force. 
         FIG. 27  is a cross-sectional side view of a tissue anchor device with an exchange ring formed as a rigid ring. 
         FIG. 28  is a cross-sectional side view of a tissue anchor device with an exchange ring formed as a bearing. 
         FIG. 29  is a cross-sectional side view of a tissue anchor device with an exchange ring formed as a disk-shaped bearing. 
         FIG. 30  is a cross-sectional side view of a tissue anchor device with an exchange ring formed as a ring with a transverse bar. 
         FIG. 31  is a top view of an exchange ring formed as a ring with a transverse bar. 
         FIG. 32  is a cross-sectional side view of a tissue anchor device with an exchange ring attached to a shaft with at least one bearing further attached to the shaft. 
         FIG. 33  is a perspective view of a distal tip with a proximal groove and a transverse bar forming a suture exchange fitting. 
         FIG. 34  is a perspective view of a body of a tissue anchor device with a proximal groove and a transverse bar forming a suture exchange fitting. 
         FIG. 35  is a cross-sectional side view of a tissue anchor device with an exchange ring attached to a ball. 
         FIG. 36  is a side view of a double-looped suture. 
         FIG. 37  is a side view of threading a first suture end through a second suture end during a suture exchange. 
         FIG. 38  is a side view of pulling a first suture end and attached second suture end during a suture exchange. 
         FIG. 39  is a top view of a suture loop formed from a bifurcation of a suture. 
         FIG. 40  is a block diagram summarizing elements of a surgical kit. 
         FIG. 41  is a flow chart summarizing a method of attaching a soft tissue to a bone using at least one tissue anchor device. 
         FIG. 42A ,  FIG. 42B ,  FIG. 42C ,  FIG. 42D ,  FIG. 42E , and  FIG. 42F  are schematic diagrams illustrating a single row repair using at least one tissue anchor device. 
         FIG. 43A ,  FIG. 43B ,  FIG. 43C ,  FIG. 43D ,  FIG. 43E ,  FIG. 43F , and  FIG. 43G  are schematic diagrams illustrating a wide single row repair using at least one tissue anchor device. 
         FIG. 44A ,  FIG. 44B ,  FIG. 44C ,  FIG. 44D ,  FIG. 44E ,  FIG. 44F , and  FIG. 44G  are schematic diagrams illustrating a double row repair using at least one single-loaded tissue anchor device. 
         FIG. 45A ,  FIG. 45B ,  FIG. 45C ,  FIG. 45D ,  FIG. 45E ,  FIG. 45F , and  FIG. 45G  are schematic diagrams illustrating a double row repair using at least one double-loaded tissue anchor device. 
         FIG. 46A ,  FIG. 46B ,  FIG. 46C ,  FIG. 46D ,  FIG. 46E ,  FIG. 46F , and  FIG. 46G  are schematic diagrams illustrating a transosseous double row repair using at least one double-loaded tissue anchor device. 
         FIG. 47A  and  FIG. 47B  are schematic diagrams illustrating knotless fixation methods for double-row repairs using at least one single-loaded or double-loaded tissue anchor device. 
         FIG. 48A ,  FIG. 48B ,  FIG. 48C ,  FIG. 48D ,  FIG. 48E , and  FIG. 48F  are schematic diagrams illustrating alternative double row repairs using at least one single-loaded or double-loaded tissue anchor device. 
         FIG. 49A ,  FIG. 49B ,  FIG. 49C ,  FIG. 49D ,  FIG. 49E ,  FIG. 49F ,  FIG. 49G ,  FIG. 49H ,  FIG. 49I , and  FIG. 49J  are schematic diagrams illustrating a labrum repair using at least one single-loaded or double-loaded tissue anchor device. 
         FIG. 50A ,  FIG. 50B  and  FIG. 50C  are cutaway views of a tissue anchor device that includes a free-swiveling exchange ring. 
     
    
    
     Corresponding reference characters and labels indicate corresponding elements among the views of the drawings. The headings used in the figures should not be interpreted to limit the scope of the claims. 
     DETAILED DESCRIPTION 
     In various aspects, a suture anchor device is provided herein for the attachment of soft tissues to bone. The suture anchor device may include a body which is inserted into bone tissue. The suture anchor device may further include a suture exchange fitting situated within a passage formed in the body. The suture exchange fitting may enable one or more repair sutures to be shuttled or exchanged through the suture anchor device after the body has been implanted in bone. The sutures may be looped at one or both ends; each loop may reversibly trap an end of a second suture, and the loop may pull the second suture through a suture exchange fitting and/or a soft tissue during a suture exchange. The suture exchange fitting may be further configured to collapse if subjected to a sufficiently high suture pulling force, thereby locking in any sutures present within the suture exchange fitting. 
     In various other aspects, a surgical kit is provided herein that may include the suture anchor device, instructions for the use of the suture anchor device, and an insertion tool or implanting the suture anchor device in the bone tissue of a subject. In other additional aspects, a method of anchoring a soft tissue to a bone using one or more tissue anchors is provided herein. 
     I. Tissue Anchor 
     One embodiment disclosed herein includes a tissue anchor that may be inserted into bone tissue to which a soft tissue is to be attached using one or more sutures in a variety of suture patterns and/or arrangements. In various aspects, the tissue anchor may include one or more suture loading features to enable the loading of one or more sutures into the tissue anchor device after deployment of the tissue anchor into the bone tissue. These one or more suture loading features may further enable the exchange of sutures between one or more additional tissue anchor deployed at other locations within the bone tissue. The one or more tissue anchors may provide robust anchor points for the secure attachment of an overlying soft tissue including, but not limited to, a tendon or ligament to the underlying bone tissue. In various other aspects, additional features of the tissue anchor as disclosed herein may facilitate suture exchange by reducing pull-through forces, may inhibit anchor pullout, and/or may reduce the likelihood of suture failure due to suture breakage, knot failure, and the like. 
       FIG. 1  is a side view of a tissue anchor  100  in an aspect. The tissue anchor  100  may include a body  102  with a proximal end  104  and a distal end  106  opposite to the proximal end  104 . The proximal end  104  may include a proximal opening  108  configured to receive one or more sutures  110 . In use, the distal end  106  of the tissue anchor  100  may be advanced into a bone tissue (not shown) using an insertion tool (not shown) reversibly attached at the proximal end  104  of the tissue anchor  100 . In an aspect, the outer surface  112  of the tissue anchor  100  may include an external thread  114  to facilitate the insertion of the tissue anchor  100  into the bone tissue. 
       FIG. 2  is a longitudinal cross-section of the tissue anchor  100  in an aspect. The one or more sutures  110  may be retained within a passage  116  extending from the proximal opening  108  toward the distal end  106  along a longitudinal axis  118  of the passage  116 . Each suture  110  may pass through an aperture  302  within a suture exchange fitting  300  situated within the passage  116 . In an aspect, the suture exchange fitting  300  may be recessed distally within the passage  116  relative to the proximal opening  108 . In another aspect, the passage  116  and aperture  302  may be sized to permit a sliding motion of the one or more sutures  110  through the suture exchange fitting  300  to enable the exchange of suture in and out of the tissue anchor  100  and between two or more tissue anchor  100  using a sufficiently low pulling force as described herein below. 
     The tissue anchor device  100 , including various features of the body  102  and suture exchange fitting  300  are described in detail herein below. 
     a. Body 
     Referring again to  FIG. 1 , the tissue anchor device  100  includes a body  102  with a proximal end  104  and a distal end  106 . In various aspects, the body  102  may be inserted into bone tissue to provide a robust anchor for one or more sutures used to attach a soft tissue including, but not limited to, a tendon or ligament to the bone tissue. As such, the external shape of the body  102  may be an elongated cylindrical profile similar to the external profile of known orthopedic fasteners including, but not limited to, bone screws. 
     In various aspects, the body  102  may have an outer diameter  124  ranging from about 2 mm to about 8 mm. The outer diameter  124  of the body  102  may depend on any one or more factors including, but not limited to: the accessible area of bone tissue within which the tissue anchor device  100  is to be inserted, the desired anchoring strength of the tissue anchor device  100 , and the size and number of sutures to be anchored by the tissue anchor device  100 . Larger outer diameters  124  may be selected for applications requiring higher anchoring strength. Further, larger outer diameters  124  may be selected for anchoring large diameter sutures and/or multiple sutures. In various other aspects, the outer diameter  124  may range from about 2 mm to about 2.2 mm, from about 2.1 mm to about 2.3 mm, from about 2.2 mm to about 2.4 mm, from about 2.3 mm to about 2.5 mm, from about 2.4 mm to about 2.6 mm, from about 2.5 mm to about 2.7 mm, from about 2.6 mm to about 2.8 mm, from about 2.7 mm to about 2.9 mm, from about 2.8 mm to about 3.0 mm, from about 2.9 mm to about 3.1 mm, from about 3.0 mm to about 3.2 mm, from about 3.1 mm to about 3.3 mm, from about 3.2 mm to about 3.4 mm, from about 3.3 mm to about 3.5 mm, from about 3.4 mm to about 3.8 mm, from about 3.6 mm to about 4.0 mm, from about 3.8 mm to about 4.2 mm, from about 4 mm to about 4.4 mm, from about 4.2 mm to about 4.6 mm, from about 4.4 mm to about 4.8 mm, from about 4.6 mm to about 5.0 mm, from about 4.8 mm to about 5.25 mm, from about 5.0 mm to about 5.5 mm, from about 5.25 mm to about 5.75 mm, from about 5.5 mm to about 6.0 mm, from about 5.75 mm to about 6.25 mm, from about 6.0 mm to about 6.5 mm, from about 6.25 mm to about 6.75 mm, from about 6.5 mm to about 7.0 mm, from about 6.75 mm to about 7.25 mm, from about 7 mm to about 7.5 mm, from about 7.25 mm to about 7.75 mm, or from about 7.5 mm to about 8 mm. 
     In various other aspects, the body  102  may have a length  126  ranging from about 5 mm to about 50 mm. The length  126  may vary in proportion to the outer diameter of the body  102 . In various aspects, the ratio of the length  126  to the outer diameter  124  of the body  102  may be 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 6:1, 8:1, or 10:1. In various additional aspects, the length  126  of the body  102  may range from about 5 mm to about 10 mm, from about 7.5 mm to about 12.5 mm, from about 10 mm to about 15 mm, from about 12.5 mm to about 17.5 mm, from about 15 mm to about 20 mm, from about 17.5 mm to about 22.5 mm, from about 20 mm to about 30 mm, from about 25 mm to about 35 mm, from about 30 mm to about 40 mm, from about 35 mm to about 45 mm, and from about 40 mm to about 50 mm. 
     1. External Threads 
     Referring again to  FIG. 1 , the body  102  may further include at least one external feature to facilitate the implantation of the tissue anchor device  100  into the bone tissue, and to enhance the anchor strength of the tissue anchor device  100  during long-term use. Any known external feature suitable for orthopedic anchor devices may be formed on the body  102  including, but not limited to: one or more circumferential rings typical of push-in suture anchors, and one or more threads  114  helically extending about an exterior of the body  102  as illustrated in  FIG. 1 . In one aspect, the external feature may be one or more threads  114  extending along at least a portion of the length  126  of the body  102 . The one or more threads  114  may have any configuration suitable for use in an orthopedic anchoring device including, but not limited to: single threads with a constant thread pitch, single threads with a variable pitch, self-tapping threads, and double-helix threads. 
       FIG. 3  is a transparent side view of a tissue anchor device  100  with a double helix thread in one aspect. As illustrated in  FIG. 3 , the double helix thread includes a first thread  114 A and a second thread  114 B; both threads  114 A/ 114 B may start at the proximal end  104  oriented about 180° from one another. In this aspect, the double helix threads  114 A/ 14 B may enable a relatively high thread density, which may enhance bone fixation of the tissue anchor device  100 , while maintaining a relatively high thread pitch, which may reduce the number of turns associated with driving the tissue anchor device  100  into the bone tissue. Compared to a double helix thread, a single helix thread may have a lower thread pitch to enable an equivalent thread density, and as a result may drive the tissue anchor device  100  into the bone tissue with a higher number of turns during implantation. 
     2. Distal End 
     Referring again to  FIG. 1 , the distal end  106  of the body  102  may be configured to facilitate the implantation of the tissue anchor device  100 . Referring again to  FIG. 2 , the distal end  106  of the body  102  may further include a lead-in  130  in one aspect. The lead-in  130  may be tapered at the distal end  106  and may further be non-threaded. The profile of the lead-in  130  may be any suitable profile including, but not limited to: a conical profile, a spherical profile, a pointed profile, and any other suitable profile. 
     In one aspect, the body  102  may be a solid body with no internal passage, lumen, or the like. In this aspect, a suture exchange fitting  300  may be formed in other configurations, such as an eyelet formed in the solid body  102  for receiving multiple thicknesses or strands of a suture. In this aspect, the body  102  may include a suture exchange fitting  300  attached to the proximal end  104  of the body  102 , as illustrated in  FIG. 5 . In other aspects, the suture exchange fitting  300  may be attached at any other location on the solid body  102  without limitation. In yet other aspects, the suture exchange fitting  300  may include one or more bores (not shown) formed through the solid body  102  at any location on the body  102  without limitation. 
     3. Interior Passage 
     In another aspect, illustrated in  FIG. 2 , the body  102  may further include an interior passage  116  extending from the proximal opening  108  toward the distal end  106  for at least a portion of the length  126  of the body  102 . In various aspects, the passage  116  may have an inner diameter  128  ranging from about 1 mm to about 6 mm. The inner diameter  128  may be selected to maintain a minimum material thickness throughout the body  102  to maintain the structural integrity of the tissue anchor device  100  during implantation and long-term use. In addition, the inner diameter may further be selected to provide sufficient space to exchange one or more sutures  110  with suitably low pulling resistance and/or to maintain a sufficiently large aperture  302  of the suture exchange fitting  300  for suture exchange. 
     In various aspects, the ratio of the inner diameter  128  to the outer diameter  124  of the body  102  may be about 1:10, about 1:9, about 1:8, about 1:7, about 1:6, about 1:5, about 1:4, about 1:3, about 1:2, about 1:1.5, and about 1:1.2. In various aspects, the passage  116  may have an inner diameter  128  ranging from about 1 mm to about 2 mm, from about 1.5 mm to about 2.5 mm, from about 2 mm to about 3 mm, from about 2.5 mm to about 3.5 mm, from about 3 mm to about 4 mm, from about 3.5 mm to about 4.5 mm, from about 4 mm to about 5 mm, from about 4.5 mm to about 5.5 mm, and from about 5 mm to about 6 mm. 
     In an aspect, the inner diameter  128  of the passage  116  may be sufficiently large to accommodate the width and the minimum mass width of the sutures  110  loaded into the tissue anchor device  100 . The minimum mass width of the sutures  110 , as used herein, refers to the width of double the number of sutures present in the tissue anchor device  100 , and allows for the additional widths of any sutures that may be exchanged from an additional tissue anchor device  100 . By way of non-limiting example, the mass width of the sutures  110  for a triple loaded tissue anchor device  100  may be 3 sutures  110 , each looped through the aperture  302 , for a total suture mass equal to the collective width of six sutures  110 . An exchanged suture would result in an additional suture  110  being exchanged or pulled through the aperture  302 , and this exchanged suture  110  may also fold over or otherwise represent a mass of double its single strand width during the suture exchange. 
     As described in detail herein below, the suture exchange may involve a pull of a first suture that is threaded through the aperture  302  and may further involve linking to a second suture that is also threaded through the aperture  302 ; the first and second suture may each contribute two ends that extend proximally from the aperture  302  through the passage  116 , resulting in four lengths of suture occupying the passage  116  during a suture exchange, because each of the sutures is folded within the body  102  of the tissue anchor device  100 . In various other aspects, the inner diameter  128  of the body  102  may be sufficiently large to accommodate the width and the minimum mass width of one (single loaded) #2 suture, 2 (double loaded) #2 sutures, or three (triple loaded) #2 sutures, combined with the added width of an exchanged #2 suture from a nearby anchor. In all cases, the minimum width must accommodate the loaded width and exchange width equal to twice the individual width of a #2 suture. 
     In various aspects, the inner diameter  128  of the passage  116  may be sized to reduce the pulling friction as one or more sutures  110  are pulled through the aperture  302  within the passage  116 . In other aspects, the passage may further include additional features to reduce pulling friction. In one aspect, the passage  116  may be configured to avoid the inclusion of potential pinch points and/or friction points that may impede suture exchange, catch a suture during a suture exchange, and/or otherwise reduce suture exchange efficiency. In one non-limiting example, illustrated in  FIG. 2 , the inner wall  120  defining the passage  116  may be formed as a continuously smooth surface with no abrupt transitions between regions of the passage  116  that may result in sharp edges against which a suture  110  may rub. In another non-limiting example, the proximal opening  108  may include a chamfer  136  to reduce the sharpness of the lip surrounding the proximal opening  108 . 
     Referring again to  FIG. 5 , the suture exchange fitting  300  may protrude proximally from the proximal end  104  of the body  102  in an aspect. In this one aspect, the passage  116  need not accommodate the sliding of one or more sutures  110 , because the aperture  302  is not situated within the passage  116 . In this aspect, the inner diameter  128  may be reduced to less than the width and/or the minimum mass width of two or more sutures  110  within the body  102 . However, this arrangement of the suture exchange fitting  300  at the proximal end  104  of the body  102  may result in contact between the aperture  302  and the soft tissue contacting the surface of the bone above the proximal end  104  of the tissue anchor device; this contact may lead to increased friction between the aperture  302  and the one or more sutures  110  during a suture exchange, and/or irritation and/or inflammation of the soft tissue that may prolong healing of the soft tissue. To reduce the contact between the aperture  302  and the soft tissue, the body  102  may be sufficiently counter-sunk into the bone tissue to situate the aperture  302  below the bone surface. However, the overlap between the bone anchor and the rigid cortical bone may be reduced by this countersinking thereby reducing the overall fixation strength of the anchor. 
     4. Tool Fitting and Vent Holes 
     In various aspects, the proximal end  104  of the body  102  may be configured to engage one or more tools used to implant the tissue anchor device  100  within the bone tissue.  FIG. 4  is a top perspective view of a body  102  showing the proximal opening  108 . In an aspect, the proximal opening may include a tool fitting  134  configured to receive a tool (not shown) used to insert the body  102  into the bone tissue. The tool fitting  134  may be configured to receive any suitable orthopedic insertion tool including, but not limited to, a torsional driver, an impact tool such as a slap hammer or impact hammer, and any other suitable tool. The tool fitting  134  may have any suitable profile corresponding to an orthopedic anchor insertion tool including, but not limited to: single-blade screwdriver, a cruciform driver, a Phillips-head screwdriver, a star-head driver, a hexagonal driver as illustrated in  FIG. 4 , and any other suitable tool fitting profile. In another aspect, the tool fitting  134  may include a chamfer  136  (see  FIG. 4 ), fillet or other feature at the entry point of the tool fitting  134  to facilitate the insertion of the implantation tool into the proximal end  104  of the body  102 . 
     Referring again to  FIG. 1 , the body  102  may further include additional features to enhance the healing of the bone tissue in the vicinity of the implanted tissue anchor device  100  and/or to enhance the adhesion or integration of bone tissue into the external surface of the body  102 . In one aspect, the body  102  may include one or more vent holes  132  extending from the exterior surface of the body  102  into the passage  116  within the body  102 . In this aspect, the one or more vent holes  132  may facilitate the migration of red blood cells and other cells and biofluids into the body  102  and may further facilitate contact of these cells and biofluids with the bottom surface of the soft tissue adjacent to the bone tissue, thereby promoting healing. In another aspect (not shown) the exterior surface of the body  102  may further include one or more depressions including, but not limited to dimples, blind bores, and/or indentations. In this other aspect, the one or more depressions may enhance the contact area of the body  102  with the surrounding bone tissue. In addition, the one or more depressions may be filled with one or more bioactive substances to promote healing of the bone tissue and overlying soft tissue. Non-limiting examples of suitable bioactive substances include: anti-inflammatory compounds, antibiotics, immunosuppressant compounds, and/or tissue growth stimulants such as bone growth factor. 
     In various aspects, the body  102  may be formed using any suitable biocompatible material of sufficient strength without limitation. In various aspects, any one or more known materials for orthopedic fasteners may be used to construct the body  102  including, but not limited to: metals and alloys including stainless steel, titanium, and titanium alloys, and biocompatible plastics and polymers such as PEEK. In one aspect, the body  102  may be constructed of a single material. In another aspect, the body  102  may be a composite structure composed of two or more materials. 
     b. Distal Tip 
     Referring to  FIG. 6 , the body  102  may be provided as a single segment extending from the proximal end  104  to the distal end  106  in one aspect. In this aspect, the distal end  106  may include a distal opening  138  through which a suture exchange fitting  300  may be inserted. In other aspects, the tissue anchor device  100  may further include a distal tip  200  in addition to the body  102 . In these other aspects, the distal tip  200  may be received and/or may be configured to be received in the distal opening  138  of the body  102 . The two-piece design of these other aspects may facilitate the assembly of the tissue anchor device  100 . 
     1. Proximal Shaft 
       FIG. 7  is an exploded view of a tissue anchor device  100  that includes the body  102  and distal tip  200  in an aspect. In this aspect, the distal tip  200  may include a proximal shaft  202  protruding in a proximal direction. The proximal shaft  202  may be configured to fit within the distal opening  138  of the body. In another aspect, the distal tip  200  may further include a flange  204  with an outer diameter that is larger than the diameter of the distal opening  138 , thereby providing a mechanical stop to limit the degree of insertion of the proximal shaft  202  into the distal opening  138 . In this other aspect, the body  102  may be further provided with a distal face  140  against which the flange  204  of the distal tip  200  may press when the body  102  and distal tip  200  are assembled to form the tissue anchor device  100  as illustrated in  FIG. 8 . In this aspect, the outer diameter of the flange  204  may be essentially matched to the outer diameter of the distal end  106  of the body  102 , such that the body  102  an distal end  200  form a relatively smooth profile when assembled, as illustrated in  FIG. 9 . In yet another aspect, the passage  116  within the body may include a step  142  which has a smaller dimension than the proximal shaft  202 , within the passage  116  inside the body  102  may also serve to stop the distal tip  200  from sliding into the body  102 . 
     Referring again to  FIG. 8 , the proximal shaft  202  of the distal tip  200  may be press-fit into the distal opening  138  of the body  102 . Without being limited to any particular theory, the forces on the tissue anchor device  100  are typically applied in a proximal direction along the longitudinal axis  118  of the tissue anchor device  100 . Loads may be applied to the distal tip  200  and may serve to further seat the proximal shaft  202  within the distal opening  138  of the body  102 , thereby maintaining a secure coupling between the distal tip  200  and the body  102  without the addition of any other materials or processing. In one aspect, the coupling between the distal tip  200  and the body  102  may be a force fit or a friction fit. In other aspects, an adhesive or other biocompatible bonding agent or bonding process may be used to maintain or improve the coupling between the distal tip  200  and the body  102 . 
     Referring again to  FIG. 7 , the distal tip  200  and the body  102  of the distal opening  138  may further include mechanical elements (not shown) to maintain or improve the coupling between the distal tip  200  and the body  102 . Any known interlocking mechanical elements may be incorporated into the distal tip  200  and body  102  including, but not limited to, roughened surface textures, additional elements such as compression washers and the like, and interlocking mechanical elements such as meshing threads. In one aspect, the outer surface  210  of the proximal shaft  202  and receiving surface  144  of the distal opening  138  may include surface roughening (not shown). In another aspect, a compression washer or washer with a roughened texture (not shown) may be inserted over the proximal tip  202  prior to assembly of the tissue anchor device  100 . In an additional aspect, the outer surface  210  of the proximal shaft  202  may include a threaded portion (not shown) that may intermesh with a threaded receptacle (not shown) formed on the receiving surface  144  of the distal opening  138 ; the distal tip  200  may be rotated to advance the threaded portion into the threaded receptacle of the distal opening  138 . In another additional aspect, the outer surface  210  of the proximal shaft  202  may include one or more tabs or protrusions (not shown) that may intermesh with one or more tracks or slots (not shown) formed on the receiving surface  144  of the distal opening  138 . In this other additional aspect, the distal tip may be advanced into the distal opening  138  with the one or more tabs or protrusions upon the outer surface  210  of the proximal shaft  202  aligned with one or more gaps (not shown) formed in the one or more tracks or slots on the receiving surface  144 ; the distal tip  200  may then be rotated a partial turn up to about 45 degrees to advance the tabs or protrusions of the distal tip  200  into the tracks or slots of the distal opening  138 , thereby locking the distal tip  200  in place. 
     In various aspects, the distal tip  200  may be formed using any suitable biocompatible material of sufficient strength without limitation. In various aspects, any one or more known materials for orthopedic fasteners may be used to construct the distal tip  200  including, but not limited to: metals and alloys including stainless steel, titanium, and titanium alloys, and biocompatible plastics and polymers such as PEEK. In one aspect, the distal tip  200  may be constructed of a single material. In another aspect, the distal tip  200  may be a composite structure composed of two or more materials. In yet another aspect, the distal tip  200  and body  102  may be constructed of similar metal compositions to prevent oxidation-reduction reactions between the body  102  and distal tip  200  that may degrade one or both components over long-term use. 
     2. Retention Features for Suture Exchange Fitting 
     Referring again to  FIG. 8 , the distal tip  200  may further include one or more additional features to retain the suture exchange fitting  300  at a desired position and to further maintain the aperture  302  of the suture exchange fitting  300  in an open position to facilitate the exchange of sutures within the aperture  302 . By way of non-limiting example, these additional features may include a distal recess  206  formed within the distal end  208  of the distal tip  200  to secure the suture exchange fitting  300  in a fixed position near the distal end  106  of the body  102 . Various aspects of additional features of the distal tip  200 , as well as the body  102 , to retain the suture exchange fitting  300  are described in detail herein below. 
     c. Suture Exchange Fitting 
     Referring again to  FIG. 2 , the tissue anchor device  100  may further include a suture exchange fitting  300  with an aperture  302  in various aspects. The aperture  302  may enable repair sutures to be shuttled or exchanged through the body  102  of the tissue anchor device  100  after the tissue anchor device  100  has been implanted in bone tissue and may further enable the repair sutures to be passed through soft tissue in one aspect. In another aspect, the aperture  302  may be configured to remain fully open during each suture exchange, thereby maintaining the suture friction and associated suture pulling force at acceptably low levels. Without being limited to any particular theory, a relatively high suture friction and/or suture pulling force may degrade the effectiveness of the tissue anchor device  100  due to reduction in surgical tactile feel during suture exchange and/or an inability to execute the pull-through of sutures due to increased suture pulling forces. In another aspect, the aperture  302  of the suture exchange fitting  300  may be configured to close or collapse once the load or tension applied to the repair sutures exceed a particular threshold collapsing force, thereby preventing further suture exchanges. 
     During suture exchange and the initial passage of one or more repair sutures  110  through the soft tissue, the aperture  302  may maintain a space sufficiently large to allow for the passage of up to several sutures  110  through the body  102  of the tissue anchor device  100  after implantation in the bone tissue as described herein above. As described herein below, each suture  110  exchanged through an aperture  302  may be doubled over and as a result, the aperture  302  may be sized to accommodate the unimpeded passage of 2 sutures for every desired suture exchange. In one aspect, the aperture  302  may be sized to accommodate a single suture exchange, corresponding to the passage of at least two sutures  110  simultaneously. In another aspect, the aperture  302  may be sized to accommodate two suture exchanges concurrently, corresponding to the passage of at least four sutures  110  simultaneously. In an additional aspect, the aperture  302  may be sized to accommodate three or more suture exchanges concurrently, corresponding to the passage of at least six sutures  110  simultaneously. 
     In addition, the aperture  302  and associated suture exchange fitting  300  may be provided with sufficient strength to withstand the pulling forces that are applied by the one or more repair sutures  110 , thereby maintaining the space within the aperture  302  essentially unchanged throughout the suture exchange process and fixation of a soft tissue to a bone tissue using the tissue anchor device  100 . Non-limiting examples of puling forces applied by the one or more repair sutures  110  during the exchange process include: tension resulting from pulling one or more repair sutures and/or friction resulting from the sliding of the one or more sutures through the aperture  302 . In another aspect, additional tension in the suture may result from pulling multiple sutures through multiple tissue layers and/or multiple tissue anchor devices  100  with multiple apertures  302  during the course of an orthopedic repair procedure as described herein below. In one aspect, the pulling force applied by the one or more repair sutures  110  during the exchange and repair process may be less than about 20 lbs. In various other aspects, the pulling force may be less than about 19 lbs., less than about 18 lbs., less than about 17 lbs., less than about 16 lbs., less than about 15 lbs., less than about 14 lbs., less than about 13 lbs., less than about 12 lbs., less than about 11 lbs., less than about 10 lbs., less than about 8 lbs., less than about 4 lbs., or less than about 2 lbs. 
     During a suture exchange, the direction of sliding of the one or more sutures  110  may aligned at a variety of angles relative to the initial orientation of the sutures  110  and the aperture  302 . Without being limited to any particular theory, a fixed suture exchange fitting  300  that is unable to rotate may develop pinch points, suture cross-over tensions that may impede a suture exchange, and/or tortuosities that may restrict or prevent the completion of a suture exchange. In various aspects, the aperture  302  and associated suture exchange fitting  300  may be configured to rotate within a predetermined range during a suture exchange due to torsion resulting from pulling one or more repair sutures  110  in a direction offset from a plane coincident with the aperture  302 . Referring again to  FIG. 2 , the suture exchange fitting  300  may include an exchange ring  304  defining the aperture  302  in one aspect. In this aspect, the exchange ring  304  may be configured to rotate and/or deform under torsional loads to maintain a sufficiently large aperture  302  for the suture exchange process. In another aspect, the exchange ring  304  and associated aperture  302  may consist of rounded shapes and edges to reduce the potential of binding, pinching, or otherwise impeding the sliding of one or more sutures  110  through the aperture  302  during a suture exchange. In this other aspect, the exchange ring  304  may be configured to include only internal angles of greater than about 90°. In one aspect, the exchange ring  304  may be provided in an essentially semicircular shape, as illustrated in  FIG. 2 . 
     In an aspect, the predetermined range through which the exchange ring  304  may rotate relative to an initial position of the exchange ring  304  in the absence of a torsional load may be up to about 360°. In this aspect, a rotation of the exchange ring  304  up to about 360° enables the suture exchange fitting  300  to accommodate a variety of suture loads and movements associated with a suture exchange and/or fixation of a soft tissue to an underlying bone tissue, without collapse of the aperture  302  and associated increase in pulling friction of the one or more sutures  110 . Without being limited to any particular theory, it is thought that rotations of the exchange ring  304  to angles over 360° relative to the initial position of the exchange ring  304  may result in collapse of the aperture  302 . In various other aspects, the predetermined range through which the exchange ring  304  may rotate relative to an initial position of the exchange ring  304  in the absence of a torsional load may be up to about 360°, up to about 340°, up to about 320°, up to about 300°, up to about 280°, up to about 260°, up to about 200°, up to about 180°, up to about 150°, up to about 120°, up to about 90°, up to about 45°, up to about 30°, and up to about 10°. 
     In various aspects, the exchange ring  304  may be constructed from any suitable biocompatible material including, but not limited to: a metal, a plastic, or a suture or other flexible material including a woven fabric or a braided fabric. In various other aspects, the exchange ring  304  may also be provided in the form of a bar or clip machined or formed from a metal or plastic material. In these various other aspects, the bar or clip, when taken in combination with other features or structures of the body  102  and/or distal tip  200 , may define the aperture  302 . In an additional aspect, the aperture  302  may be machined, molded or formed directly into the body  102  and/or distal tip  200  of the tissue anchor device  100 . 
     In one aspect, the exchange ring  304  may be constructed from a flexible material, thereby enabling the exchange ring  304  to deform through a predefined angular range during a suture exchange and/or fixation of a soft tissue to a bone tissue using the tissue anchor device  100 . In another aspect, the suture exchange fitting  300  may be provided with a rotational coupling to the body  102  and/or distal tip  200 , thereby enabling the rotation of the exchange ring  304  without significant deformation under torsional loads. In yet another aspect, the exchange ring  304  may be provided with two or more rigid segments coupled together by one or more rotational couplings, thereby permitting a twisting movement of the two or more segments to accommodate torsional loads while maintaining a sufficiently large aperture  302  during a suture exchange and/or fixation of a soft tissue to a bone tissue using the tissue anchor device  100 . In various other aspects, any combination of any of the features described herein above including, but not limited to the flexible material, the rotational coupling, and/or the two or more segments, may be incorporated into the suture exchange fitting  300 . Detailed descriptions of the structure and function of specific suture exchange fittings  300  in various aspects are provided herein below. 
     In various aspects, the aperture  302  of the suture exchange fitting  300  may be configured to collapse, thereby essentially fixing the one or more sutures  110  in place within the tissue anchor device  100  and creating a more secure tissue fixation structure.  FIG. 10  and  FIG. 11  are side views of a suture exchange fitting  300  with the aperture  302  in an open ( FIG. 10 ) and collapsed ( FIG. 11 ) configuration in an aspect. Referring to  FIG. 10 , once the suture exchange and the initial passage of one or more repair sutures  110  through the soft tissue is completed, a collapsing force  306  may be applied to the one or more sutures  110 . This collapsing force  306  may be sufficiently high to collapse the aperture  302  into a collapsed configuration, as illustrated in  FIG. 11 . In one aspect, the collapsing force  306  applied by the one or more repair sutures  110  after the exchange process may be greater than about 20 lbs. In various other aspects, the collapsing force  306  may be greater than about 22 lbs., the collapsing force  306  may be greater than about 24 lbs., the collapsing force  306  may be greater than about 26 lbs., the collapsing force  306  may be greater than about 28 lbs., the collapsing force  306  may be greater than about 30 lbs., the collapsing force  306  may be greater than about 35 lbs., the collapsing force  306  may be greater than about 40 lbs., the collapsing force  306  may be greater than about 45 lbs., the collapsing force  306  may be greater than about 50 lbs., the collapsing force  306  may be greater than about 60 lbs., the collapsing force  306  may be greater than about 70 lbs., the collapsing force  306  may be greater than about 80 lbs., or the collapsing force  306  may be greater than about 100 lbs. 
     1. Flexible Suture Exchange Fittings 
     In an aspect, at least a portion of the suture exchange fitting  300  may be a flexible elongated element constructed from a flexible material including, but not limited to, a suture material. Non-limiting examples of suture materials suitable for inclusion in a suture exchange fitting  300  include: non-absorbable suture materials such as polyethylene, polyester, and the like; absorbable suture materials such as a lactide-glycolide copolymer and the like; and any combination thereof. In one aspect, the inclusion of flexible materials in the suture exchange fitting  300  may enable the deformation of the suture exchange fitting  300  under torsional loads during suture exchange, as well as the collapse of the aperture  302  under the collapsing force  306  as described herein above. 
       FIG. 12  and  FIG. 13  are side and top views, respectively, of a distal tip  200  with a suture exchange fitting  300  that has been deformed by a torsion resulting from the twisting of a suture  110  within the aperture  302 . In this aspect, the exchange ring  304  may be constructed of a flexible material, thereby enabling the deformation of the exchange ring  304  from an initial position  304 ′ through a twist angle  308 . The exchange ring  304  may twist through a predetermined range as described herein above including, but not limited to up to about 360°. In this aspect, the predetermined range may be influenced by any one or more of at least several factors, described herein below. 
     In one aspect, the structural integrity of the exchange ring  304  may be sufficient to maintain the aperture  302  in an open position in the presence of any forces and torques exerted on the exchange ring  304  by one or more sutures  110  in association with a suture exchange and/or fixation of a soft tissue to a bone tissue using the tissue anchor device  100 . In an aspect, the exchange ring  304  may resist deforming in response to a suture pulling force with a magnitude up to the collapsing force as described herein above. In another aspect, the exchange ring  304  may permit twisting within a predetermined angular range as described herein above in response to a torsion exerted by the one or more sutures  110  as described herein above. The structural integrity of the exchange ring  304  may be influenced by any one or more of at least several factors including, but not limited to: the properties of the material used to construct the exchange ring such as tensile strength and torsional stiffness, the dimensions of the exchange ring  304 , additional support provided by the body  102  and/or distal tip  300 , and the reinforcement of at least a portion of the exchange ring  304 . 
     In an aspect, the exchange ring  304  may be formed from a single braided suture. In other aspects, at least a portion of the exchange ring  304  may be stiffened or shaped using an application of heat to adhere two or more strands of the braided suture and/or through the application of a coating to the braided suture material. In additional aspect, a coating applied to the exchange ring  304  may further reduce the friction between the exchange ring  304  and one or more sutures  110  sliding through the aperture  302  during a suture exchange or tightening of a suture during fixation of a soft tissue to a bone tissue using the tissue anchor device  100 . In various other aspects, the exchange ring  304  may be constructed from other materials including, but not limited to wire, monofilaments, metals, and the like. Non-limiting examples of suitable coating materials include acrolytes, silicones; polyurethanes; polylactic acid; polyglycolic acid and other degradables; and fibrin glue. In other aspects, the coating may be applied to a portion of the exchange ring  304  or to the entire exchange ring  304  as needed. 
     In an aspect, the structural integrity of the exchange ring  304  may be influenced by the dimensions of the exchange ring  304 .  FIG. 14  is a side view of a distal tip and suture exchange fitting  300  with a relatively small aperture  302  in one aspect.  FIG. 15  is a side view of a distal tip and suture exchange fitting  300  with a relatively large aperture  302  in another aspect. In both aspects, the aperture size may be quantified by one or more dimensions of the aperture  302  including, but not limited to, a maximum height  310 , a maximum width  312 , and an aperture area  314 . 
     Referring again to  FIG. 14  and  FIG. 15 , the maximum height  310  with respect to the maximum width  312  of the exchange ring  304  may influence the overall performance of the suture exchange. A relatively longer maximum height  310  (see FIG.  15 ) may increase the rotational flexibility of the exchange ring  304 ; however, excessive maximum height  310  may permit the ring exchange ring  304  to easily twist more than 360° which may effectively collapse the aperture  302 , thereby hindering a suture exchange. A relatively shorter maximum height  310  (see  FIG. 14 ) may better resist twisting and collapse and thereby better maintain an open aperture compared to a taller exchange ring  304 ; however, if the exchange ring  304  is too short the aperture  302  may be too small to accommodate the combined mass of all sutures  110  and may thereby hinder a suture exchange. 
     In various aspects, the ratio of the maximum width  312  to the maximum height of the aperture  310  may range from about 1:10 to about 3:1. In various other aspects, the ratio of the maximum width  312  to the maximum height of the aperture  310  may range from about 1:10 to about 1:8, from about 1:9 to about 1:7, from about 1:8 to about 1:6, from about 1:7 to about 1:5, from about 1:6 to about 1:4, from about 1:5 to about 1:3, from about 1:4 to about 1:2, from about 1:3 to about 1:1, from about 1:2 to about 2:1, and from about 1:1 to about 3:1. 
     In an aspect, the aperture area  314  may be sufficient to accommodate a single, double, or triple suture material mass, corresponding to a single loaded, double loaded, or triple loaded tissue anchor device  100 , respectively. In another aspect, the aperture area  314  may provide additional space for a first suture to shift position relative to a second suture.  FIG. 16  is a side view of a triple-loaded suture exchange fitting  300  in which the aperture area  314  provides additional space for a first suture  110  to change positions relative to a second suture  110 A. 
     i) First and Second Spaced-Apart Locations 
     In an aspect, the structural integrity of the suture exchange fitting  300  may be enhanced by securing at least a portion of the suture exchange fitting  300  to the body  102  and/or the distal tip  200  at a first and second spaced-apart location. In this aspect, the secured portions of the suture exchange fitting  300  may be maintained in separated positions, thereby maintaining the aperture  302  of the suture exchange fitting  300  in an open position.  FIG. 17  is a side cross-sectional view of a tissue anchor device  100  in which the exchange ring  304  of the suture exchange fitting  300  is secured within the passage  116  of the body at a first spaced-apart location  146  and at a second spaced-apart location  148 . The first and second spaced-apart locations  146 / 148  are typically positioned on opposite positions within the lumen  116  in order to maintain the aperture  302  in as wide-open a position as possible within the lumen  116 . 
     The exchange ring  304  of the suture exchange fitting  300  may be secured within the lumen  116  of the body  102  by any known means without limitation. Referring again to  FIG. 17 , the inner wall  120  of the body  102  may be provided with a pair of fixation fittings  150 / 152  through which the exchange ring  304  may be threaded, thereby fixing the exchange ring  304  at the first and second spaced-apart locations  146 / 148 . Any suitable fixation fitting may be used without limitation. In one aspect, the fixation fittings  150 / 152  may be a mechanical fitting including, but not limited to: a ring (see  FIG. 17 ), a hook, or a loop. In another aspect (not shown) the exchange ring  304  may be affixed to the inner wall  120  at the first and second spaced-apart locations  146 / 148  using a biocompatible adhesive. In yet another aspect (not shown) the exchange ring  304  may be affixed by melting the inner wall  120  and/or portions of the exchange ring  304  at the first and second spaced-apart locations  146 / 148 . In various aspects, the fixation fittings  150 / 152  may be configured to release the secured portions of the exchange ring  304  when the exchange ring  304  is subjected to a collapsing force  306 , to enable the collapsing of the aperture  302  once a suture exchange through the exchange ring  304  is completed. 
     In other aspects, at least a portion of the exchange ring  304  may be affixed at first and second spaced-apart locations  146 / 148  situated on the distal tip  200  at a first and second side  212 / 214  in order to maintain the aperture  302  in an open position. In these other aspects, the exchange ring  304  may be affixed to the distal tip  200  and then the distal tip  200  may be inserted into the distal opening  138  of the body  102 . Once assembled, the exchange ring  304  is situated proximal to the distal tip  200  within the passage  116  of the body  102 , as illustrated in  FIG. 2 . 
     Referring to  FIG. 18 , the first and second side  212 / 214  of the distal tip  200  may be provided with a first and a second channel  216 / 218  configured to hold at least a portion of the exchange ring  304  in one aspect. The first and second channels  216 / 218  may be aligned with the longitudinal axis  118  of the tissue anchor device  100  in an aspect. In another aspect, the first and second channels  216 / 218  may extend over at least a portion of the distal tip  300 . 
     Referring again to  FIG. 7 , the first and second channels  216 / 218  may be grooves extending the entire length of the distal tip  300 . In this aspect, the exchange ring  304  of the suture exchange fitting  300  may be wrapped around the distal tip  200  with portions of the exchange ring situated within the first and second channels  216 / 218 , as illustrated in  FIG. 8 ; the exchange ring  304  may be wrapped around the distal tip  200  before the distal tip  200  is pressed into the body  102 . Once the proximal shaft  202  is inserted into the distal opening  138  of the body  102 , the portions of the exchange ring  304  are retained between the first and second channels  216 / 218  and the inner wall  120  of the distal opening  138 . In this aspect, the distal tip  200  maintains the aperture  302  of the exchange ring  300  in an open position and prevents the aperture  302  from collapsing. 
       FIG. 19  is a side cross-sectional view of an exchange ring  304  constructed from a single piece of a flexible material including, but not limited to a suture, in which the flexible material is affixed at the first and second spaced-apart locations  146 / 148  in an aspect. As illustrated in  FIG. 19 , the first and second spaced-apart locations  146 / 148  may correspond to different sides of the distal tip  200  as described herein previously. In this aspect, the flexible material may include a first tail  316  situated between the flange  204  of the distal tip  200  and the distal face  140  of the body  102 . The flexible material may further include a second tail  318  situated between the flange  204  of the distal tip  200  and the distal face  140  of the body  102  opposite to the first tail  316 . In this aspect, the first and second ends  318  may be held in place by compressive forces between the distal tip  200  and the body  102  as described herein previously. In another aspect, the flange  204  and/or the distal face  140  may include additional features (not shown) to enhance the fixation of the first and second ends  316 / 318  including, but not limited to: grooves or channels formed in the flange  204  and/or distal face  140 , 
     In another aspect (not illustrated), the first and second spaced-apart locations  146 / 148  situated on the distal tip  200  may be provided in the form of a first lumen and a second lumen formed through the distal tip  200 . The first and second lumens may be aligned with the longitudinal axis  118  of the tissue anchor device  100  and may open at the proximal shaft  202  and the distal end  208  of the distal tip  200 . The first and second lumens may further be situated near the outer perimeter of the distal tip  200  and located at opposite sides of the distal tip  200 . In this other aspect, the exchange ring  304  may be formed from a single length of a flexible material as described herein previously, with the first tail  316  threaded through the first lumen and the second tail  318  threaded through the second lumen. The first tail and the second tail may be glued and/or melted within the first and second lumens. The first and second tails may be threaded through the first and second lumens and the distal ends of the first and second tails knotted to prevent the tails from retracting proximally through the lumens; each tail may be knotted separately, or the first and second tails may be knotted to one another. 
       FIG. 20  is a side view of a distal tip  200  and suture exchange fitting  300  in an aspect. In this aspect, the exchange ring  304  may be created by adhering the first tail  316  and the second tail  318  of a single length of a flexible material including, but not limited to, a suture segment directly to the distal tip  200  at first and second spaced-apart locations  146 / 148 ; the first and second tails  316 / 318  may also be directly overmolded into the distal tip  200  at the first and second spaced-apart locations  146 / 148 . In this aspect, the distal tip  200  may be provided with a proximal face  220  to provide a surface suitable for adhering the first and second tails  316 / 318 . In another aspect, the proximal face  220  may be provided with one or more fixation features (not shown) at the first and second spaced-apart locations  146 / 148  to further facilitate the adhesion of the first and second tails  316 / 318  to the distal tip  200 . Non-limiting examples of suitable fixation features include depressions, grooves, channels, bores, lumens, and raised features such as clips, hooks, and the like. 
     ii) Flexible Exchange Rings 
     In various aspects, the exchange ring  304  may be constructed from any suitable flexible material without limitation. In one aspect, the exchange ring  304  may be constructed from standard suture. In another aspect, the suture may be a continuous ring including, but not limited to a suture formed through a continuous braiding process. In this one aspect, the first tail  316  and the second tail  318  may extend into one another in a continuous manner to form the continuous loop. 
     In another aspect, the suture may be a single piece ending in a first tail  316  and a second tail  318 . In this other aspect, the first tail  316  and a second tail  318  may be secured to the body  102  and/or distal tip  200  at a first spaced apart location  146  and at a second spaced-apart location, respectively, as described herein previously. 
     In yet another aspect, the first tail  316  and the second tail  318  of the suture may be tied to one another in a knot to form the exchange ring  304 . Referring again to  FIG. 7  and  FIG. 8 , the knot  320  may be situated near the distal end  208  of the distal tip  200 . In an aspect, the distal end  208  may include a feature to retain the knot  230  including, but not limited to, a distal recess  206 . In various aspects, the knot  320  may be one of any variety of suitable knots. However, the knot  320  may be configured to avoid undesirable stress concentrations in the suture that may result in a premature failure of the exchange ring  304 , and may be further configured to withstand any anticipated loads on the tissue anchor device  100  during prolonged use without slipping or untying. 
     In an aspect, the knot  320  may be reinforced to prevent slipping or untying using any suitable knot reinforcement method. Non-limiting examples of suitable knot reinforcement methods include: heating and melting the first and second tails  316 / 318  of the knot  320 , applying a stiff material to the first and second tails  316 / 318  of the knot  320 , and any combination thereof. In another aspect, the knot  320  may also be set and/or reinforced by heating and melting the outer surface  322  of the entire knot in order to stiffen the material without compromising the strength of the suture. In an additional aspect, an adhesive or other coating may be applied to the outer surface  322  of the knot  320  to stiffen and reinforce the knot  320 . Non-limiting examples of suitable adhesives or other coatings include: polymers, epoxies, adhesives, plastics, and any combination thereof. 
     In an aspect, the stiffness of at least a portion of the exchange ring  304  formed from a flexible material may be modified by the addition of one or more reinforcement features. In one aspect, the flexible material may be heated and/or melted in one or more portions to stiffen the one or more portions of the exchange ring  304 . In another aspect, at least a portion of the flexible material may be coated, impregnated, and/or overmolded with adhesive or other coating material including, but not limited to: polymers, epoxies, adhesives, plastics, and any combination thereof. The stiffness of the supporting material can be controlled to allow the ring to collapse once a defined load has been reached. 
     In another aspect, the first tail  316  and the second tail  318  may be joined by a joining member (not shown) configured to retain the first and second tails  316 / 318 , thereby forming the continuous ring. The joining member may be any suitable joining device including, but not limited to: a splice, a clamp, and a joiner. The joining member may be constructed from any suitable material including, but not limited to: metals, polymers, epoxies, adhesives, plastics, and any combination thereof. The joining member may be affixed to the first and second tails  316 / 318  by any suitable mechanism including, but not limited to: crimping, molding, twisting, advancing a clamp screw or set screw, repositioning a latch, and any other suitable mechanism. In an aspect, the joining member may be seated within a distal recess  206  formed within the distal tip  200  opposite to the distal end  208 , as illustrated in  FIG. 8 . 
     In another aspect, the stiffness of at least a portion of the exchange ring  304  formed from a flexible material may be stiffened by the incorporation of additional reinforcing elements. The additional reinforcing elements may be incorporated at any portion of the exchange ring  304  and may be attached, imbedded or otherwise incorporated as described herein below. In various aspects, the one or more additional reinforcing elements may be configured to fail upon exposure to a load in excess of a collapsing force  306  to enable the collapsing of the aperture  102  and locking of the one or more sutures  110  within the aperture  102  after completion of a suture exchange. 
       FIG. 21  is a side view of an exchange ring  304  that includes a flexible material and an external reinforcing element  322 . In one aspect, the external reinforcing element  322  may be provided in the form of a sleeve situated over the top of the exchange ring  304 , as illustrated in  FIG. 21 . In another aspect, the external reinforcing element  322  may be provided in the form of a U-shaped reinforcement structure situated on at least a portion of the inner surface of the exchange ring  304  adjacent to the aperture  302 , as illustrated in  FIG. 22 . In these aspects, the external reinforcing element  322  may be constructed of any suitably stiff and biocompatible material including, but not limited to: a polymer, a plastic, a metal, a suture sleeve, and any combination thereof. This approach may also create a smooth bearing interface to allow a repair suture  110  to more easily slide through the aperture  302  during an exchange process. To this end, the external reinforcing element  322  may be constructed of a material characterized by a relatively low friction coefficient. 
       FIG. 23  is a side view of an exchange ring  304  that includes a flexible material and an internal reinforcing element  324 . In one aspect, the internal reinforcing element  324  may be provided in the form of a reinforcing insert  324  situated in a suture lumen  326 . In one aspect, the top of the exchange ring  304 . In this aspect, the external reinforcing element  322  may be constructed of any suitably stiff and biocompatible material including, but not limited to: a polymer, a plastic, a metal including NiTi, stainless steel, and/or titanium, and any combination thereof. 
     In various aspects, the stiffness of the reinforcing element  322 / 324  may be modulated through a variety of means to allow the exchange ring  304  to collapse once the collapsing force  306  has been exceeded after a suture exchange. The dimensions of the reinforcing element  322 / 324  may be configured to create a region of high stress that may collapse upon exposure to a force in excess of the collapsing force  306 . By way of non-limiting example, the reinforcing element  322 / 324  may include a local thin or hollow region configured to fail, thereby enabling the collapse of the exchange ring  304 . The reinforcing element  322 / 324  may be provided in the form of a composite element in which one or more regions may be constructed from a weaker material configured to preferentially fail before the remainder of the reinforcing element  322 / 324 , thereby enabling the collapse of the exchange ring  304 . The reinforcing element  322 / 324  may further include one or more regions in which a portion of the material has been removed, including, but not limited to defects, cutouts, gaps, and/or perforations.  FIG. 24  is a side view of an internal reinforcing element that includes a defect  328  configured to preferentially fail and collapse the exchange ring  304  at sufficiently high loads. 
     2. Rigid Suture Exchange Fittings 
     In various aspects, the exchange ring  304  may also be constructed from any suitable rigid and biocompatible material without limitation. Non-limiting examples of suitable rigid materials include: polymers, plastics, metals including NiTi, stainless steels, and/or titanium and titanium alloys, and any combination thereof. In one aspect, the exchange ring  304  may be constructed from a wire, a braided cable, a coated wire, a coated braided cable, a molded plastic, and any other suitable rigid structure. In an aspect, the rigid material of the exchange ring  304  may provide a smooth bearing interface defining the aperture  302  to allow the repair suture  110  to more easily slide through the exchange ring  304  during the exchange process. Further, the rigid exchange ring  304  may be well-suited to maintain the aperture  302  in the presence of various loads associated with a suture exchange. In an aspect, the stiffness of the rigid exchange ring  304  may be modulated through a variety of means to allow the exchange ring  304  to collapse once the collapsing force  306  has been exceeded after a suture exchange. The dimensions of the exchange ring  304  may be configured to create a region of high stress that may collapse upon exposure to a force in excess of the collapsing force  306 . By way of non-limiting example, the exchange ring  304  may include a local thin or hollow region configured to fail, thereby enabling the collapse of the exchange ring  304 . The exchange ring  304  may be provided in the form of a composite element in which one or more regions may be constructed from a weaker material configured to preferentially fail before the remainder of the exchange ring  304 , thereby enabling its collapse. The exchange ring  304  may further include one or more regions in which a portion of the material has been removed, including, but not limited to defects, cutouts, gaps, and/or perforations. 
     In one aspect, the rigid exchange ring  304  may be relatively limited with respect to the range of rotation of the aperture  102  enabled during a suture exchange. In various other aspects, the suture exchange fixture  200  may include additional features to enable the rotation of the exchange ring  304  within a predetermined range during a suture exchange as described previously herein. These additional features may enable rotation of a rigid suture exchange fixture  200  within a limited range. Non-limiting examples of additional features include various cylindrical or spherical cavities formed within the passage  116  of the body and/or the distal tip  200  that may interact with one or more features of the suture exchange fitting  300  to enable the rotation of the aperture  302  during a suture exchange. In another additional aspect, the rigid exchange ring  304  may include additional features to permit the exchange ring  304  to freely swivel without limitation. 
       FIG. 50A ,  FIG. 50B  and  FIG. 50C  are cutaway views of a tissue anchor device  100  that include a free-swiveling rigid exchange ring  304  in one aspect. Referring to  FIG. 50A , the tissue anchor device  100  in this aspect may include the exchange ring  304 , positioned within the passage  116  of the tissue anchor device  100 . The exchange ring  304  may be configured to rotate or swivel freely with respect to the body  102  of the tissue anchor device  100 . The swiveling functionality in this aspect decouples the rotational orientation of the exchange ring  304  from the rotational orientation of the body  102  of the tissue anchor device  100 , thereby allowing the orientation of one or more sutures  110  threaded through the aperture  302  of exchange ring  304  in any desired direction without regard to the rotation of the body  102  of the tissue anchor device  100 . 
       FIG. 50A  illustrates a cut-away view of the tissue anchor device  100  that includes the free-swiveling exchange ring  304  in one aspect. A first rotational orientation of the body  102  is illustrated in  FIG. 50A , with a body landmark  190  shown as a reference. The exchange ring  304  may be positioned within the aperture  302  of body  102 . As shown in  FIG. 50A , the rigid exchange ring  304  may be retained via a flexible link  192  that permits essentially unlimited rotation about the screw axis. 
     In various aspects, the link  192  may be constructed from any suitable flexible material without limitation including, but not limited to, a thread or suture material. The link  192  may be provided in any form without limitation including, but not limited to, a strip, a loop, a band, or any other suitable flexible form capable of enabling free rotation of the exchange ring  304 . As illustrated in  FIG. 50A , the flexible link  192  may be provided in the form of a suture or thread that is doubled and looped through the aperture  302  of the exchange ring  304  and passed through the distal opening  138  within the distal tip  200  of the tissue anchor device  100  in an aspect. In this aspect, the distal end  196  of the link  192  may terminate in a knot  194  or other suitable joining or terminating structure to retain the distal end  196  outside of the distal tip  200 , thereby providing a robust and swiveling attachment of the exchange ring  304  to the body  102 . The exchange ring  304  may be of a different structure or configuration than that shown in  FIG. 50A  that allows free-swiveling movement relative to the body  102  of the tissue anchor device  100  without departing from the spirit of the invention. 
       FIG. 50B  is an illustration of the tissue anchor device  100  shown in  FIG. 50A  with the body  102  rotated at a 45° angle about the screw axis relative to the orientation shown in  FIG. 50A , as evidenced by the change in orientation of the body landmark  190 . As shown in  FIG. 50B , while the body  102  of the tissue anchor device  100  is rotated at a 45° angle, the orientations of the exchange ring  304  and aperture  302 , the link  192 , and the one or more sutures  110  are unchanged from the orientations illustrated in  FIG. 50A . 
       FIG. 50C  is an illustration of the tissue anchor device  100  shown in  FIG. 50A  with the body  102  rotated at a 90° angle about the screw axis relative to the orientation shown in  FIG. 50A , as evidenced by the change in orientation of the body landmark  190 . As shown in  FIG. 50C , while the body  102  of the tissue anchor device  100  is rotated at a 90° angle, the orientations of the exchange ring  304  and aperture  302 , the link  192 , and the one or more sutures  110  are unchanged from the orientations illustrated in  FIG. 50A  and  FIG. 50B . 
     The decoupling of the rotational orientation of the exchange ring  304  from those elements of the tissue anchor device  100  affixed within a bone provides advantages that would be appreciated by those of skill in the art. The exchange ring  304  may rotationally orient in a direction that minimizes the tortuosity of the path traversed by the one or more sutures  110  threaded through the aperture  302  of the exchange ring  304 . In contrast, a suture  110  loaded into a fixed thread-holding member (not shown) may become twisted when the suture anchor device (not shown) is deployed and screwed into a bone. Without being limited to any particular theory, reducing the tortuosity of the suture&#39;s path may reduce the amount of force required to exchange one or more sutures  110  between one or more tissue anchor devices  100  as described herein. Swiveling may further allow a suture  110  threaded through an exchange ring  304  to slide with minimal tortuosity when tensioning the suture  110  within a particular repair construct as described herein below. 
       FIG. 25  is a cross-sectional side view of a tissue anchor device  100  with a rigid exchange ring provided in the form of a bar or clip  330  in an aspect. In this aspect, the clip  330  may be contained within a cavity  222  formed within the distal tip  200 . The lower wall  224  of the cavity may be relatively wide, thereby permitting the clip  330  to rotate within the cavity  222  during a suture exchange. In an aspect, the cavity  222  may include an annular groove (not shown) formed in the lower wall  224  within which the ends  332  of the clip  330  may slide to enable rotation of the aperture  302  during a suture exchange. In this aspect, the annular groove may extend around the entire circumference of the lower wall  224 , or the annular groove may extend over a portion of the circumference of the lower wall  224  to constrain the rotation of the clip  330  to within a limited range. In this aspect, the upper wall  224  may taper proximally from the relatively wide lower wall  224  to a narrow neck  230 . During a suture exchange, the clip  330  may be subjected to relatively low pulling forces from the one or more sutures  110 . After completion of the suture exchange, a pulling force in excess of the collapsing force  306  may cause the clip  330  to deform into a collapsed clip  330 ′ in which the ends  332  of the clip  330 ′ are forced together by the narrow diameter of the neck  230 . In the collapsed configuration, the clip  330 ′ may entrap the one or more sutures  110 , thereby preventing any further sliding movements. 
       FIG. 26  is a cross-sectional side view of a tissue anchor device  100  with a rigid exchange ring  304  provided in the form of a U-shaped clip  330  in another aspect. In this other aspect, the U-shaped clip  330  may be contained within a cavity  222  formed within the distal tip  200 . The wall  224  of the cavity  222  may be relatively wide, thereby permitting the U-shaped clip  330  to rotate within the cavity  222  during a suture exchange. In an aspect, the cavity  222  may include an annular groove (not shown) formed in the wall  224  within which the ends  332  of the U-shaped clip may slide to enable rotation of the aperture  302  during a suture exchange in a manner similar to the annular groove described herein previously in connection with the suture exchange fitting  300  of  FIG. 25 . In this aspect, the distal tip may further include a relatively narrow neck  230  situated distally to the cavity  222 . During a suture exchange, the U-shaped clip in the open configuration is subjected to relatively low pulling forces from the one or more sutures  110  and freely rotates within the cavity  222 . After completion of the suture exchange, the U-shaped clip may be pushed down distally into the neck  230 , thereby forcing the ends  332  of the clip  330  to deform into a collapsed clip  330 ′. In the collapsed configuration, the collapsed clip  330 ′ may entrap the one or more sutures  110 , thereby preventing any further sliding movements. The ends  332  of the clip  330 ′ may include barbs  333  that may retain the ends  332  within the cavity  222 ; the collapsed clip  330 ′ may resist unlocking from the cavity  222  even when the repair sutures  110  are tensioned. 
       FIG. 27  is a cross-sectional side view of a tissue anchor device  100  with an exchange ring  304  provided in the form of a rigid exchange ring  304  in an additional aspect. In this additional aspect, the rigid exchange ring  304  may freely float within a cavity  222  formed within the tissue anchor device  100 . In various aspects, the cavity  222  may be formed within the body  102  or within the distal tip  200  of the tissue anchor device  100 . The rigid exchange ring  304  defines an aperture  302  that is sufficiently large to allow for a suture exchange. The rigid exchange ring  304  may also to rotate with respect to the longitudinal axis  118  of the tissue anchor device  100 . In another aspect, the cavity  222  may be provided with one or more ridges (not illustrated) or other mechanical stops to limit the rotation of the rigid exchange ring  304  within a limited rotational range inside of the cavity  222 . In an aspect, the ridges may be aligned parallel with the longitudinal axis  118  of the tissue anchor device  100 . 
       FIG. 28  is a cross-sectional side view of a tissue anchor device  100  with an exchange ring  304  provided in the form of a bearing  334  in another aspect. In this other aspect, the bearing  334  may be situated in a cavity  222  formed between the body  102  and within the distal tip  200  of the tissue anchor device  100 . In an aspect, the bearing  334  may be provided as an essentially cylindrical bar with a circumferential groove  336  or neck in the mid-section of the bearing  334 . The bearing  334  may be free to rotate about its own axis  338  which would ease a suture exchange. The bearing  334  may also be free to rotate around the longitudinal axis  118  of the tissue anchor device  100  to allow the one or more repair sutures  110  (not shown) to self-align in the direction of suture tension. The groove  336  provides a guide for the one or more sutures  110  and prevents any sutures  110  from becoming pinched between the inner wall  120  of the body  102  and the bearing  334 .  FIG. 29  is a perspective view of a disk-shaped bearing  334 A with a groove  336  formed at the mid-section of the bearing  334 A in another aspect. 
       FIG. 30  is a cross-sectional side view of a tissue anchor device  100  with an exchange ring  304  provided in the form of a bearing  334 B in another aspect. In this other aspect, the bearing  334  may be situated in a cylindrical cavity  222  formed between the body  102  and within the distal tip  200  of the tissue anchor device  100 . In an aspect, the bearing  334 B may be provided as a ring  340  with a transverse bar  342  across the ring  340 .  FIG. 31  is a top view of the bearing  334 B in this aspect. The bearing  334 B may be free to rotate about its own axis  338  which would ease a suture exchange. The bearing  334  may also be free to rotate around the longitudinal axis  118  of the tissue anchor device  100  to allow the one or more repair sutures  110  (not shown) to self-align in the direction of suture tension. The groove  336  provides a guide for the one or more sutures  110  and prevents any sutures  110  from becoming pinched between the inner wall  120  of the body  102  and the bearing  334 .  FIG. 31  is a perspective view of a disk-shaped bearing  334 A with a groove  336  formed at the mid-section of the bearing  334 A in another aspect. 
       FIG. 32  is a cross-sectional side view of a tissue anchor device  100  with an exchange ring  304  attached to a shaft  344  provided with one or more bearings  340 / 342  in another aspect. In this aspect, the exchange ring  304  may be attached to a proximal end  346  of the shaft  344 , and a first bearing  340  may be attached to a distal end  348  of the shaft  344  opposite to the proximal end  346 . A second bearing  342  may also be attached to a middle portion of the shaft  344  between the exchange ring  304  and the first bearing  340 . The exchange ring  304  may be situated within the passage  116 , rendering the aperture  302  accessible to the one or more sutures  110  via the proximal opening  108  of the body  102 . The first bearing  340  may be retained within a second cavity  232  formed within the distal end  200 , and the second bearing  342  may be retained within a cavity  222  formed between the distal end  106  of the body  102  and the proximal shaft  202 . The first bearing  340  and the second bearing  342  may freely rotate about the longitudinal axis  118  of the tissue anchor device  100 . The body  102  may have a narrow neck  230  defined at a distal end of the aperture  116  to entrain the shaft  344  between the exchange ring  304  and the second bearing  342 . One or more sutures  110  may be looped through the aperture  302  in this aspect. 
       FIG. 33  is a perspective view of a distal tip  200  in which a groove  234  is formed in the proximal shaft  202  in an aspect. A bar  350  may be inserted across transverse to the groove  234  to form a suture exchange fitting  300 . One or more sutures  110  may be inserted through an aperture  302  formed between the bar  350  and the base  236  of the groove  234 . The bone anchor can be constructed such that it has a transverse break in the proximal section of the body of the bone anchor to create a space for the suture exchange. The entire tip assembly may be attached to the body  102  (not shown) via the distal opening  138 . The distal tip  200  may be configured to freely rotate about the longitudinal axis  118  of the tissue anchor device  100 .  FIG. 34  is a perspective view of a body  102  within which a groove  154  is formed within the proximal end  104  of the body  102  in an aspect. In this aspect, a bar  350  may be inserted transversely across the groove  154 . One or more sutures  110  may be looped through the aperture  302  formed between the bar  350  and the base  156  of the groove  154 . 
     In both of the aspects illustrated in  FIG. 33  and  FIG. 34 , the bar  350  may be provided in a variety of cross-sectional shapes and lengthwise profiles without limitation. In an aspect, the bar may be configured to provide a low-friction suture exchange fitting  300  capable of accommodating a range of suture pulling forces and changes in the directions of suture pulling forces associated with a suture exchange and the fixation of a soft tissue to a bone tissue using the tissue anchor device  100 . Non-limiting examples of suitable cross-sectional shapes for the bar  350  include circular, elliptical, crescent-shaped and the like. Non-limiting examples of suitable lengthwise profiles for the bar  350  include: linear, as illustrated in  FIG. 33  and  FIG. 34 ; and curved including an arched, parabolar, and/or semi-circular lengthwise profile. In another aspect, the bar may  164  be provided with additional features including, but not limited to: local thinning of the bar  350  cross-sectional dimension and/or notches, perforations and/or or other defects formed within at least a portion of the bar  350 , and any combination thereof to enable the collapse of the bar  350  into a collapsed configuration when the bar is subjected to a pulling force in excess of a collapsing force as described herein previously. 
       FIG. 35  is a cross-sectional side view of a tissue anchor device  100  with the suture exchange fitting  300  provided in the form of an exchange ring  304  attached to a ball  352  that is pulled into a socket  156  formed at the distal opening  138  of the bone anchor body  102  or at the distal end  138  of the distal tip  200 . The exchange ring  304  may consist of a prefabricated ring produced from a material including, but not limited to, a metal, a polymer, a plastic, a suture, and the like. The exchange ring  304  may be attached to the ball  352  using any method including, but not limited to: overmolding the ball  352  onto a portion of the exchange ring  304  and/or bonding the exchange ring  304  onto the ball  352  with a biocompatible adhesive. The ball  325  may be pulled from outside the distal end  208  or distal opening  138  into the socket  156  by pulling in a proximal direction on the exchange ring  304  either directly or via one or more sutures  110  looped through the aperture  302  within the exchange ring  304 . In an aspect, the ball  352  and socket  156  may be matched in profile to enable the free rotation of the aperture about the longitudinal axis  118  of the tissue anchor device  100 . 
     d. Sutures 
     Referring again to  FIG. 2 , the tissue anchor device  100  may further include one or more sutures  110  looped through the suture exchange fitting  300  within the body  102  of the tissue anchor device  100 . Each suture  110  may include a single loop situated at one end of the suture  110 , or two loops situated at opposite ends of the suture  110 . In one aspect, a suture  110  with a single loop may enable a suture exchange in a single direction (away from the single loop) whereas a suture with a pair of loops may enable suture exchanges in two directions, thereby enhancing the range of functions potentially performed by the suture  110  within the tissue anchor device  100 . The one or more sutures  110  may be exchanged between different tissue anchor devices  100  (not shown) and may be used to anchor a soft tissue to an underlying bone tissue as described in further detail herein below.  FIG. 36  is an illustration of a suture  110  in one aspect. In this aspect, each suture  110  may include a main suture length  158  ending at a first suture loop  164  attached at a first suture end  160  and a second suture loop  166  attached at a second suture end  162  opposite to the first suture end  160 . 
     In various aspects, the suture loops  164 / 166  may act as snares to reversibly hold and guide the end of a second suture  172  as the second suture  172  is pulled through tissue and/or an aperture  302  of a tissue anchor device  100 .  FIG. 37  is a schematic view of an initial step in a suture exchange from a second tissue anchor device  100 ′ to a first tissue anchor devices  100  in one aspect. In this aspect, a first suture end  160 ′ and a first suture loop  164 ′ of a second suture  172  are threaded through the first suture loop  164  of the first suture  170 ; this threading results in the second suture  172  being doubled over the first loop  164  of the first suture  170 . The second suture end  162  of the first suture  170  may then be pulled away from the first tissue anchor device  100  to pull the second suture  172  through the first tissue anchor device  100 .  FIG. 38  is a schematic illustration of a subsequent stage of the suture exchange shown in  FIG. 37 . As illustrated in  FIG. 38 , the first loop  164  and doubled over second suture  172  have been pulled through the aperture  302  (not shown) of the first tissue anchor device  100 , resulting in the second suture  172  being threaded through both the first tissue anchor device  100  and the second tissue anchor device  100 ′. The second suture  172  may now be pulled at both the first suture end  160 ′ and the second suture end  162 ′ to compress the soft tissue  402  against the underlying bone tissue  404 . 
     In various aspects, the sutures  110  may be constructed of any suitable suture material without limitation. In an aspect, the sutures may be constructed of a material including, but not limited to: a monofilament, a tubular suture material, a braided suture material, and any combination thereof. Non-limiting examples of suture materials suitable for inclusion in a suture exchange fitting  300  include: non-absorbable suture materials such as polyethylene, polyester, Nylon, Gortex, Silk, polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene, Poly (ethylene, terephthalate), stainless steel and the like; absorbable suture materials such as a lactide-glycolide copolymer, polyglactin, monocryl, polyester poly(p-dioxanone), and panacryl and the like; and any combination thereof. In one aspect, the inclusion of flexible materials in the suture exchange fitting  300  may enable the deformation of the suture exchange fitting  300  under torsional loads during suture exchange, as well as the collapse of the aperture  302  under the collapsing force  306  as described herein above. 
     In various aspects, the size of the sutures  110  may be any size for use in an orthopedic surgical procedure consistent with the use of the tissue anchor device  100  without limitation. In one aspect, the suture diameter may range from about 0.02 mm (USP #10-0) to about 0.8 mm (USP #4). In other aspects, the suture diameters may range from about 0.02 mm to about 0.06 mm, from about 0.04 mm to about 0.08 mm, from about 0.06 mm to about 0.10 mm, from about 0.08 mm to about 0.12 mm, from about 0.10 mm to about 0.14 mm, from about 0.12 mm to about 0.16 mm, from about 0.14 mm to about 0.18 mm, from about 0.16 mm to about 0.20 mm, from about 0.18 mm to about 0.22 mm, from about 0.20 mm to about 0.30 mm, from about 0.25 mm to about 0.35 mm, from about 0.30 mm to about 0.40 mm, from about 0.35 mm to about 0.45 mm, from about 0.40 mm to about 0.50 mm, from about 0.45 mm to about 0.55 mm, from about 0.50 mm to about 0.60 mm, from about 0.55 mm to about 0.65 mm, from about 0.60 mm to about 0.70 mm, from about 0.65 mm to about 0.75 mm, from about 0.70 mm to about 0.80 mm, Non-limiting examples of suitable suture diameters include: USP #10-0 (0.02 mm), USP #9-0 (0.03 mm), USP #8-0 (0.04 mm), USP #7-0 (0.05 mm), USP #6-0 (0.07 mm), USP #5-0 (0.10 mm), USP #4-0 (0.15 mm), USP #3-0 (0.20 mm), USP #2-0 (0.30 mm), USP #0 (0.35 mm), USP #1 (0.40 mm), USP #2 (0.50 mm), USP #3 (0.60 mm), USP #5 (0.70 mm), and USP #6 (0.8 mm). 
     In various other aspects, the sutures  110  may have an overall length ranging from about 2.5 cm to about 70 cm. In additional aspects, the sutures  110  may have an overall length ranging from about 2.5 cm to about 10 cm, from about 5 cm to about 15 cm, from about 10 cm to about 20 cm, from about 15 cm to about 25 cm, from about 20 cm to about 30 cm, from about 25 cm to about 35 cm, from about 30 cm to about 40 cm, from about 35 cm to about 45 cm, from about 40 cm to about 60 cm, and from about 50 cm to about 70 cm. 
     Referring again to  FIG. 36 , the one or more sutures  110  may have suture loops  164 / 166  at opposite ends  160 / 162  of the suture  110 . In an aspect, the dual suture loops  164 / 166  enable the suture  110  to be pulled toward the first suture end and/or the second suture end  162  as needed in the course of a surgical procedure. The double suture loops  164 / 166  enable suture pull-through in any direction, change of direction, multiple-anchor utilization, after insertion of the tissue anchor device  100 , during post-insertion linkage changes, and during a remedial surgical procedure including, but not limited to reverse a repair and/or changing a method of linkage. 
     In an aspect, the first and second loops suture loops  164 / 166  may be configured to pull a second suture  172  through a soft tissue and/or an aperture  302  within a tissue anchor device  100 . As a consequence, the strength of the first and second suture loops  164 / 166  may be less than the tensile strength of the main suture length  158 , which may be subjected to relatively higher tensions in order to affix a soft tissue to an underlying bone tissue. In another aspect, the first and second loops suture loops  164 / 166  may be configured to reduce the suture tension associated with pulling the second suture  172  and optionally one or more additional attached sutures  110 ′ through the soft tissue and/or aperture  302 . In this other aspect, the first and second loops suture loops  164 / 166  may be constructed with a low profile configuration including one or more of at least several features including, but not limited to: relatively low suture diameter, compact collapsed size, smooth transition between the suture end  160 / 162  and the corresponding suture loop  164 / 166 . 
     In one aspect, the first and second loops suture loops  164 / 166  may be constructed of the same suture material as the main suture length  158 . In this aspect, the loops  164 / 166  may be formed by forming a loop at the first and second suture ends  160 / 162  and attaching each suture tip to its respective suture end  160 / 162 . The tips may be attached by any suitable means including, but not limited to: continuous braiding of the loop, biocompatible adhesive, melting/welding, and any combination thereof. In another aspect, the first and second loops suture loops  164 / 166  may be constructed of a different or smaller-diameter material relative to the main suture length  158 . In this other aspect, the material used to construct the first and second loops suture loops  164 / 166  may reduce the overall size of the loops in a collapsed configuration, thereby reducing pulling force during a suture change. 
       FIG. 39  is top view of a first suture loop  164  formed by a bifurcation  168  of the main suture length  158  at the first suture end  164  in one aspect. In this aspect, the distal portion of the loop  164  may rejoin to form a full-diameter loop tip  174 . In this aspect, the loop  164  may be securely attached to the suture end  160  by virtue of the continuity of suture material between the main suture length  158  and the loop  164 . In addition, the transition from the suture end  160  to the loop  164  is smooth, thereby reducing the pulling friction associated with passing the loop through a soft tissue and/or aperture  304 . As the loop  160  is pulled through a soft tissue or aperture, the loop  160  may collapse to a compact size approaching that of the main suture length in this aspect. 
     In various aspects, the diameter of each loop  164 / 166  may be configured to accommodate the suture exchange of one or more sutures  110  in one aspect. In this aspect, the loop diameter may be at least 1 mm. In other aspects, smaller or larger sutures may be used and the loop size diameter may decrease or increase accordingly. In additional aspects, the loop diameter may be at least 1 mm, at least 2 mm, at least 3 mm, at least 4 mm, at least 5 mm, at least 6 mm, at least 7 mm, at least 8 mm, at least 9 mm, at least 10 mm, or at least 20 mm. In other aspects, the diameter of each loop  164 / 166  may be configured to provide a suitable grip for a surgeon&#39;s hand or a surgical tool manipulated by a surgeon, or the loop diameter may be configured to simplify the act of loading suture ends  160 / 162  into the loop  164 / 166 . In these other aspects, the diameter of each loop may be larger than the diameter that accommodates the suture exchange of one or more sutures  110 . 
     In an additional aspect, at least a portion of the suture loops  164 / 166  and/or the main suture length  158  in close proximity to the suture loops  164 / 166  may be stiffened to facilitate the loading of additional sutures  110  into the suture loops  164 / 166 , to facilitate the loading of the suture  110  by threading the suture loops  164 / 166  through an aperture  302  within a tissue anchor device  100 , to provide tactile feedback to the surgeon, and any combination thereof. In one aspect, the loops  164 / 166  may be stiffened to maintain the loops  164 / 166  in a collapsed configuration, resulting in a smaller profile during use. In another aspect, the loops  164 / 166  may be stiffened to maintain the loops  164 / 166  in an opened configuration, thereby facilitating the loading of additional sutures  110  into the loops  164 / 166  and/or to provide a larger profile for a surgeon to grip during use. IN various aspects, the loops  164 / 166  may be stiffened using any suitable method including, but not limited to heat setting, application of stiffening coatings including, but not limited to a polymer or resin coating, and any combination thereof. However, it is to be noted that the stiffening loops  164 / 166  may retain the ability to collapse during passage through an aperture  304  or tissue without unduly high suture pulling forces that may disrupt the smooth pull of the sutures  110  during a surgical procedure associated with good tactile feedback to the surgeon. 
     II. Surgical Kit 
     In an aspect, the tissue anchor device  100  described herein above may be included in a surgical kit for use by a surgeon in a surgical procedure.  FIG. 40  is a block diagram summarizing the components of the surgical kit  500  in one aspect. The surgical kit  500  may include the tissue anchor device  100  described herein above, including at least one suture  110 . The surgical kit may further provide instructions  502  and a delivery device  504 . 
     In various aspects, the instructions  502  may be provided by any suitable means including, but not limited to: printed on packaging enclosing at least some of the surgical kit  500 ; enclosed within packaging enclosing at least some of the surgical kit  500 ; accompanying the surgical kit  500 ; published as an electronic communication such as an e-mail; published on an internet website; and any combination thereof. In various aspects, the instructions  502  may include information associated with the assembly of the tissue anchor device  100 , information associated with implantation of the tissue anchor device  100 , information associated with using the tissue anchor device  100  in an orthopedic surgical procedure, and any other information relevant to the assembly and use of the tissue anchor device  100 . In this aspect, information associated with the assembly of the tissue anchor device  100  may include guidance for threading the at least one suture  110  through the aperture  302  of the suture exchange fitting  300 , passing the first and second suture ends  160 / 162  proximally through the passage  116  of the body  102  and out the proximal opening  108 , joining the distal tip  200  to the body  102  by inserting the proximal shaft  202  of the distal tip into the distal opening  138  of the body  102 , and any combination thereof. In this aspect, information associated with the implantation of the tissue anchor device  100  in an orthopedic surgical procedure may include guidance for coupling the delivery tool  504  to the tissue anchor device  100  and delivering a torque to drive the tissue anchor device  100  into the bone tissue. In this aspect, information associated with using the tissue anchor device  100  in an orthopedic surgical procedure may include guidance for exchanging one or more sutures  110  between one or more apertures  302  associated with different tissue anchor devices  100  to enable various surgical procedures including, but not limited to assembling and securing one or more suture patterns suitable for attaching a soft tissue to a bone tissue. 
     The delivery device  504  may be any driver system suitable for orthopedic fasteners without limitation. Non-limiting examples of suitable delivery devices  504  include: single-slot driver systems, star-shaped driver systems, cruciform driver systems, Phillips driver systems, hexagonal driver systems and any other suitable driver system. 
     III. Method of Anchoring Soft Tissue 
     In various aspects, one or more tissue anchor devices  100  may be used to anchor a soft tissue to a bone. The one or more tissue anchor devices  100  may be implanted in a bone and linked to one another after implantation via one or more sutures without the use of a knot or other inter-anchor fixation, thereby establishing a contiguous inter-anchor suture ending at a pair of free suture ends. Each suture end is attached to a first anchor device  100  and a last anchor device  100 ′. The free suture ends may be used for any generally accepted final repair fixation practice, including, but not limited to, anchor fixation, knotless anchor fixation, knot fixation, or linkage to additional anchor devices  100 ″. 
     In one aspect, an orthopedic repair including fixation of a soft tissue to a bone may use at least two tissue anchor devices  100  and at least one suture  110 . The suture  110  may be passed through the at least two at least two tissue anchor devices  100  using a suture exchange method described in detail herein below. Using one or more suture exchanges, a single suture  110  may form a single continuous span or linkage of suture between the at least two tissue anchor devices  100 . The single continuous suture span may end in two free ends that may be used to implement a final fixation or knot in accordance with standard surgical suture fixation practices and products. 
     In this aspect, the use of a single suture provides at least several benefits over existing knotted linkage techniques. The use of a single suture and at least two tissue anchor devices  100  as a linkage enables superior adhesion of the soft tissue to the bone compared to a knotted linkage. The use of the at least two tissue anchor devices  100  provides the capability to use a “running stich” of suture  110  for a faster and simplified repair. Because the suture  110  is not fixed at each anchor  100 , the suture  110  is capable of sliding to a limited degree between anchor points, thereby efficiently distributing the compression load over the soft tissue. Using this method, the suture tension and stress may also be distributed across multiple anchors  100 , thereby reducing the likelihood of developing single failure points in which all tension and stress may be isolated to a single anchor. The use of this method further enables the implementation of at least several suture patterns as needed, thereby enhancing the options available to the surgeon and the resulting effectiveness of the surgical procedure. 
       FIG. 41  is a flow chart summarizing a method of anchoring a soft tissue to a bone using the tissue anchor device  100  described herein above in one aspect. The method may include assembling the tissue anchor device  100  at step  602 . In one aspect, the tissue anchor device  100  may be assembled by causing the distal tip  200  that is loaded with a first suture  110 A to be received in the distal opening  138  of the body  102  such that the first suture  170  extends through the passage  116  of the body  102  and out the proximal opening  108  such that the first and second ends  160 / 162  of the first suture  170  extend proximally from the proximal opening  108 . 
     Referring again to  FIG. 41 , the method may further include attaching a delivery device  504  to the tissue anchor device  100  at step  604 . In one aspect, the first suture  170  may be extended through a lumen of the delivery device  504  such that the first and second ends  160 / 162  of the first suture  170  extend proximally from a proximal end of the delivery device  504  and a distal end of the delivery device  504  is coupled with a proximal end  104  of the body  102 , the lumen extending between a distal end of the delivery device  504  and the proximal end of the delivery device  504 . The coupled delivery device  504  may be used to torque the first tissue anchor into the bone at step  606 . In one aspect, the delivery device  504  may apply a torque to the body  102  via the distal end of the delivery device  504  coupled to the tool fitting  134  formed within the proximal opening  108  as described herein above. 
     Referring again to  FIG. 41 , the tissue anchor device  100  may be implanted into the bone at step  608 . In one aspect, a bore may be preformed within the bone prior to implanting the tissue anchor device  100 . In another aspect, if the external thread  114  of the body  102  includes a self-tapping feature, the tissue anchor device  100  may be inserted without need to form a bore beforehand. In one aspect, the tissue anchor device  100  may be implanted by advancing the body  102  and distal tip  200  into the bone until the proximal end  104  of the body  102  is essentially level with the exposed surface of the bone. In another aspect, if the suture exchange fitting  300  is situated proximally to the proximal end  104  of the body  102 , the body and the distal tip  200  may be advanced into the bone until the proximal end  104  of the body  102  is distal relative to the exposed surface of the bone. 
     The method  600  may further include extending the first and second ends  160 / 162  of the first suture  170  through the soft tissue at step  610 . The soft tissue may be any soft tissue to be reattached to a bone including, but not limited to, a tendon and/or a ligament. In an aspect, the first and second ends  160 / 162  of the first suture  170  may be extended through one or more layers, each layer including a soft tissue to be attached to the bone. A second suture  172  may be extended through a first loop  164  defined at the first end  160  of the first suture  170 .  FIG. 37  is an illustrating showing the second suture  172  extended through the first loop  164  of the first suture  170 . As illustrated in  FIG. 37 , the first end  160 ′ of the second suture  172  may now extend proximally from a second tissue anchor device  100 ′ and the second end  162 ′ of the second suture  172  may extend proximally through a soft tissue  402 . 
     In various aspects, variations of the method  600  may be used to implement a variety of suture patterns and techniques as needed to enhance the linkage between the soft tissue  402  and the bone  404 . Non-limiting examples of suture patterns and techniques include: a single suture box stitch pattern, a lateral medial bridge stitch pattern using a knotless single suture, a medial bridge, inter-implant mattress stitch pattern, a train track, a parallel horizontal repair using 2 anchors, and a medial dam suture pattern to block synovial fluid infiltration. Additional description of the suture patterns and techniques are provided herein below. 
       FIG. 42A ,  FIG. 42B ,  FIG. 42C ,  FIG. 42D ,  FIG. 42E , and  FIG. 42F  illustrate schematically a single row repair accomplished using an implanted first anchor  100  with a first suture  170  and an implanted second anchor  100 ′ with a second suture  172 . The first and second anchors  170 / 172  may be implanted as illustrated in  FIG. 42A . Referring to  FIG. 42B , a suture exchange may be started by threading the second end B 2  of the second suture  172  through the second end A 2  of the first suture  170 . As illustrated in  FIG. 42C , the exchange of the second suture  172  into the first anchor  100  is completed by pulling on the first end A 1  of the first suture  170 . The first suture  170  may then be removed from the second suture  172 , as illustrated in  FIG. 42D . The ends B 1 /B 2  of the second suture  172  may then be tensioned as illustrated in  FIG. 42E . The ends B 1 /B 2  of the second suture  172  may then be joined using a knot or a knotless joiner  176  as illustrated in  FIG. 42E . 
       FIG. 43A ,  FIG. 43B ,  FIG. 43C ,  FIG. 43D ,  FIG. 43E ,  FIG. 43F , and  FIG. 43G  illustrate schematically a wide single row repair accomplished using an implanted first anchor  100  with a first suture  170  and an implanted second anchor  100 ′ with a second suture  172 . The first and second anchors  170 / 172  may be implanted as illustrated in  FIG. 43A . Referring to  FIG. 43B , the suture ends A 1 /A 2  and B 1 /B 2  may be pulled through the soft tissue layer at widely separated locations. Referring to  FIG. 43C , a suture exchange may be started by threading the second end B 2  of the second suture  172  through the first end A 1  of the first suture  170 . As illustrated in  FIG. 43D , the exchange of the second suture  172  into the first anchor  100  is completed by pulling on the first end A 2  of the first suture  170 . The second suture may be pulled through both widely separated locations in the soft tissue near the first anchor  170  as illustrated in  FIG. 43D . The first suture  170  may then be removed from the second suture  172  to complete the suture exchange, as illustrated in  FIG. 43E . The ends B 1 /B 2  of the second suture  172  may then be tensioned as illustrated in  FIG. 43F . The ends B 1 /B 2  of the second suture  172  may then be joined using a knot or a knotless joiner  176  as illustrated in  FIG. 43G . 
       FIG. 44A ,  FIG. 44B ,  FIG. 44C ,  FIG. 44D ,  FIG. 44E ,  FIG. 44F , and  FIG. 44G  illustrate schematically a double row repair accomplished using implanted single-loaded anchors  100 A,  100 B,  100 C, and  100 D. The anchors  100 A,  100 B,  100 C, and  100 D may be implanted in a square pattern as illustrated in  FIG. 44A  and both ends of each suture may be pulled through the soft tissue over each corresponding anchor. Referring to  FIG. 44B , a suture exchange may be started by threading the first end A 1  through the first end C 1  and pulling on the second end C 2 . As illustrated in  FIG. 44C , the exchange of suture end A 1  through anchor  110 C may be completed by pulling on the suture end C 2 . Similar suture exchanges may be further accomplished to pull suture end A 2  through anchor  100 B as illustrated in  FIG. 4D  and suture end A 1  through anchor  100 D, as illustrated in  FIG. 44E . The first suture  170  may then be removed from the second suture  172  to complete the suture exchange, as illustrated in  FIG. 44E . The ends A 1 /A 2  may then be tensioned as illustrated in  FIG. 44F . The ends A 1 /A 2  may then be joined using a knot or a knotless joiner  176  as illustrated in  FIG. 44G . 
       FIG. 45A ,  FIG. 45B ,  FIG. 45C ,  FIG. 45D ,  FIG. 45E ,  FIG. 45F , and  FIG. 45G  illustrate schematically a double row repair accomplished using implanted double-loaded anchors  100 A,  100 B,  100 C, and  100 D. The anchors  100 A,  100 B may be implanted as illustrated in  FIG. 45A  and both ends of each suture may be pulled through the soft tissue over each corresponding anchor. Referring to  FIG. 45B , a suture exchange may be accomplished by threading the suture end B 3  through the suture end A 3  and pulling on the opposite suture end A 4 . Referring to  FIG. 45C , a suture exchange may be accomplished by threading the suture end B 1  through the suture end A 2  and pulling on the opposite suture end A 1 . As illustrated in  FIG. 45D , the additional double-loaded anchors  100 C and  100 D may be implanted, resulting in a square anchor pattern. Referring to  FIG. 45E , the exchange of suture ends B 1  and B 2  through anchor  110 C may be completed similarly using the two loaded sutures of anchor  100 C. Referring to  FIG. 45F , the exchange of suture ends B 3  and B 4  through anchor  110 D may be completed similarly using the two loaded sutures of anchor  100 D. The ends A 1 , A 2 , B 1 , and B 2  may then be tensioned and joined using a knot or a knotless joiner  176  as illustrated in  FIG. 45G . 
       FIG. 46A ,  FIG. 46B ,  FIG. 46C ,  FIG. 46D ,  FIG. 46E ,  FIG. 46F , and  FIG. 46G  illustrate schematically a transosseous repair accomplished using implanted double-loaded anchors  100 A,  100 B,  100 C, and  100 D. The anchors  100 A,  100 B may be implanted as illustrated in  FIG. 46A  and both ends of each suture may be pulled through the soft tissue situated over each corresponding anchor. Referring to  FIG. 46B , a suture exchange may be accomplished by threading the suture end B 3  through the suture end A 3  and pulling on the opposite suture end A 4 . Referring to  FIG. 46C , a suture exchange may be accomplished by threading the suture end B 1  through the suture end A 2  and pulling on the opposite suture end A 1 . As illustrated in  FIG. 46D , the additional double-loaded anchors  100 C and  100 D may be implanted in a different bone or at an offset location not covered by the soft tissue layer, resulting in a square anchor pattern. Referring to  FIG. 46E , the exchange of suture ends B 1  and B 2  through anchor  110 C may be completed similarly using the two loaded sutures of anchor  100 C, and the exchange of suture ends B 3  and B 4  through anchor  110 D may be completed similarly using the two loaded sutures of anchor  100 D. Referring to  FIG. 46F , the suture ends A 1 , A 2 , B 1 , and B 2  may be tensioned and retained knotlessly within corresponding anchors  100 C and  100 D. Alternatively, the ends A 1 , A 2 , B 1 , and B 2  may then be tensioned and joined using a knot or a knotless joiner  176  as illustrated in  FIG. 46G . 
       FIG. 47A  and  FIG. 47B  are schematic illustrations of additional arrangements of sutures and anchors associated with double row repairs illustrated in  FIG. 44G  and  FIG. 45G , respectively.  FIG. 47A  illustrates a double-row repair accomplished using implanted single-loaded anchors  100 A,  100 B,  100 C and  100 D. As illustrated in  FIG. 47A , the ends of the single continuous suture  170  may be crossed over and secured within a pair of implanted knotless anchors  110 E and  100 F.  FIG. 47B  illustrates a double-row repair accomplished using implanted double-loaded anchors  100 A,  100 B,  100 C and  100 D. As illustrated in  FIG. 47B , the ends of a first single continuous suture  170  may be crossed over and secured within a pair of implanted knotless anchors  110 E and  100 F, and the ends of a second single continuous suture  172  may be secured within the pair of implanted knotless anchors  110 E and  100 F without crossing over. 
       FIG. 48A ,  FIG. 48B ,  FIG. 48C , and  FIG. 48D  illustrate schematically a traditional bridged repair accomplished using implanted double-loaded anchors  100 A,  100 B,  100 C, and  100 D. The anchors  100 A,  100 B may be implanted as illustrated in  FIG. 48A  and both ends of each suture may be pulled through the soft tissue over each corresponding anchor. Referring to  FIG. 48B , a suture exchange may be accomplished by threading the suture end B 1  through the suture end A 3  and pulling on the opposite suture end A 4 . Referring to  FIG. 48C , suture ends B 1  and B 2  may be tensioned and joined with a knot. As illustrated in  FIG. 48D , the additional double-loaded anchors  100 C and  100 D may be implanted, resulting in a square anchor pattern. Referring again to  FIG. 48D , the exchange of suture ends A 1  and B 3  through anchor  110 C and the exchange of suture ends A 2  and B 4  through anchor  110 D may be completed similarly using the pairs of sutures loaded on anchors  100 C and  100 D. Referring to  FIG. 48E , the ends A 1 , A 2 , B 3 , and B 4  may be tensioned and secured using a single knotless anchor  100 E. Referring to  FIG. 48F , the suture ends A 1  and B 3  may be secured using knotless anchor  100 C, and suture ends A 2  and B 4  may be tensioned and secured using knotless anchor  100 D. 
       FIG. 49A ,  FIG. 49B ,  FIG. 49C ,  FIG. 49D ,  FIG. 49E ,  FIG. 49F ,  FIG. 49G ,  FIG. 49H ,  FIG. 49I , and  FIG. 49J  illustrate schematically repair of a labrum tear accomplished using implanted double-loaded anchors  100 A,  100 B,  100 C, and  100 D. The anchors  100 A,  100 B,  100 C, and  100 D may be implanted within a glenoid bone  180  as illustrated in  FIG. 49A , and the opposite ends of each suture may be situated at opposite sides of the overlying labrum tissue  178 . Referring to  FIGS. 49B and 49G , a suture exchange of suture end A 2  between anchor  100 A and anchor  100 B may be accomplished using one of the two sutures threaded through anchor  100 B. Referring to  FIG. 49C  and  FIG. 49H , the suture end A 2  may be threaded successively through anchors  100 B,  100 C, and  100 D in a spiral pattern using one of the loaded sutures in each corresponding anchor. As illustrated in  FIG. 49H , the suture end A 2  passes over the labrum  180  between successive anchors and passes under the labrum  180  as the suture end A 2  passes through each successive anchor. As illustrated in  FIG. 49D  and  FIG. 49I , the suture end A 2  may be exchanged from anchor  100 D to anchor  100 C using the remaining loaded suture in anchor  100 C. Referring to  FIG. 49E  and  FIG. 49J , the suture end A 2  may be threaded successively through anchors  100 B,  100 C, and  100 D in a spiral pattern using the remaining loaded suture in each corresponding anchor. As illustrated in  FIG. 49J , the suture end A 2  passes over the labrum  180  between successive anchors and passes under the labrum  180  as the suture end A 2  passes through each successive anchor; the direction of crossing is opposite to the direction illustrated in  FIG. 49H , resulting in a crossed suture pattern around the labrum  180 . Referring to  FIG. 49F , the suture ends A 1  and A 2  may be tensioned and secured with a knot or knotless joiner. 
     The foregoing merely illustrates the principles of the invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements and methods which, although not explicitly shown or described herein, embody the principles of the invention and are thus within the spirit and scope of the present invention. From the above description and drawings, it will be understood by those of ordinary skill in the art that the particular embodiments shown and described are for purposes of illustrations only and are not intended to limit the scope of the present invention. References to details of particular embodiments are not intended to limit the scope of the invention.