Abstract:
Apparatus for securing an object to bone, the apparatus comprising:
       a suture anchor assembly comprising a suture anchor body and a suture;
           the suture anchor body being configured to be lockingly disposed within a hole formed in the bone, and having an opening formed therein for slidably receiving the suture therethrough;   the suture having a first end, a second end and an intermediate portion extending therebetween;   the suture extending through the opening in the suture anchor body so that the intermediate portion forms a loop on one side of the opening and the first and second ends are disposed on the other side of the opening, such that when the first end of the suture is passed through the loop and securingly engages the object, pulling on the second end of the suture draws the loop and a captured portion of the suture along a path toward the opening in the suture anchor body;   the suture anchor body being configured so that when the suture anchor body is disposed in the hole in the bone, a tapered binding zone is established along the path followed by the loop and the captured portion of the suture when the second end of the suture is pulled, the tapered binding zone having a successively decreasing cross-sectional area such that continued pulling of the second end of the suture causes the loop and the captured portion of the suture to be jammed tightly in the tapered binding zone, whereby to bind the suture, and hence the object, to the suture anchor body, which is itself lockingly disposed within the bone.

Description:
FIELD OF THE INVENTION 
     This invention relates to surgical methods and apparatus in general, and more particularly to surgical methods and apparatus for securing soft tissue to bone. 
     BACKGROUND OF THE INVENTION 
     Various types of soft tissue are normally attached to bone. By way of example but not limitation, ligaments connect bone to bone, and tendons connect muscle to bone. By way of further example but not limitation, the labrum is soft tissue which is connected to the rim of the acetabular cup (i.e., bone) so as to form a natural seal for the hip joint. 
     Such bone-connected soft tissues may become detached from their host bone as the result of injury and/or disease. By way of example but not limitation, a ligament or tendon or labrum may all be detached from bone due to a sports-related injury. A detached ligament or tendon can cause anatomical instability, impede proper motion of the joint and cause pain. A detached or damaged labrum can impede proper motion of the hip joint and cause pain in the hip. In all of these cases, as well as numerous others, the corrective treatment typically involves surgically re-attaching the soft tissue to bone. 
     In addition to the foregoing, in some cases it may be necessary to intentionally detach soft tissue from bone in order to provide a therapeutic treatment. In these situations it is generally necessary to thereafter re-attach the soft tissue to its host bone. By way of example but not limitation, where a patient suffers from a pincer-type femoroacetabular impingement (FAI) of the hip joint, it may be necessary to remove the overgrown portion of the acetabular rim in order to alleviate the pincer-type impingement. This generally involves surgically detaching the labrum from the acetabulum, debriding the underlying acetabular bone, and then re-attaching the labrum to the acetabulum. 
     Thus it will be seen that in many cases it may be necessary or desirable to attach (or re-attach) soft tissue to bone. 
     Historically, soft tissue has been attached (or re-attached) to bone using nails, screws, staples and suture extended through holes formed in the bone. All of these approaches suffered from a variety of deficiencies, including loosening, tissue necrosis, etc. 
     More recently, suture anchor assemblies have been used to secure soft tissue to bone. More particularly, these suture anchor assemblies generally have two suture strands attached to a suture anchor body, the suture anchor body is deployed in the bone, and then the suture strands are used to tie the soft tissue to the bone. This is done by passing one or more of the suture strands through the soft tissue, properly tensioning the suture, and then tying a knot (or knots) in the free ends of the suture so as to secure the soft tissue to the bone. 
     While such suture anchor assemblies have proven to be a major advance over earlier attachment techniques, they suffer from the serious disadvantage of requiring the surgeon to tie a knot (or knots) in the suture. More particularly, it can be time-consuming and technically challenging to form a tight knot in the suture, particularly during arthroscopic procedures where the soft tissue attachment needs to take place at a remote location within the interior of a joint. Such remote knot-tying is currently done by forming a suture throw outside the joint, sliding the suture throw down to the surgical site using a suture rundown tool, forming a second suture throw outside the joint, sliding that second suture throw down to the surgical site using the suture rundown tool, etc. until the knot is formed. It will be appreciated that, at best, this procedure is time-consuming and, at worst, results in a knot which may provide inadequate securement and/or improper tension to the soft tissue. 
     The present invention is intended to provide a novel suture anchor assembly which may be used to secure soft tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture, and while permitting the surgeon to control the tension with which the soft tissue is secured to bone. 
     SUMMARY OF THE INVENTION 
     The present invention provides a novel suture anchor assembly which may be used to secure soft tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture, and while permitting the surgeon to control the tension with which the soft tissue is secured to bone. 
     The present invention generally comprises a suture anchor assembly comprising a suture anchor body and a suture slidably secured to the suture anchor body. The suture anchor body is configured to be disposed within the bone, and the suture is configured to be passed through or around the soft tissue which is to be secured to the bone. The suture anchor body and the suture are configured for knotlessly binding the suture, whereby to secure the soft tissue to the host bone. In accordance with the present invention, knotless suture binding is achieved by pulling successively increasing volumes of suture into a tapered binding zone having a successively decreasing cross-sectional area so that the sliding suture is eventually jammed, and hence bound, in position. 
     In accordance with the present invention, the tapered binding zone can be provided (i) external to the suture anchor body, by the creation of a tapered gap between the suture anchor body and the host bone, and/or (ii) internal to the suture anchor body, by providing a tapered binding zone within the suture anchor body itself. 
     In one form of the present invention, there is provided apparatus for securing an object to bone, the apparatus comprising: 
     a suture anchor assembly comprising a suture anchor body and a suture;
         the suture anchor body being configured to be lockingly disposed within a hole formed in the bone, and having an opening formed therein for slidably receiving the suture therethrough;   the suture having a first end, a second end and an intermediate portion extending therebetween;   the suture extending through the opening in the suture anchor body so that the intermediate portion forms a loop on one side of the opening and the first and second ends are disposed on the other side of the opening, such that when the first end of the suture is passed through the loop and securingly engages the object, pulling on the second end of the suture draws the loop and a captured portion of the suture along a path toward the opening in the suture anchor body;   the suture anchor body being configured so that when the suture anchor body is disposed in the hole in the bone, a tapered binding zone is established along the path followed by the loop and the captured portion of the suture when the second end of the suture is pulled, the tapered binding zone having a successively decreasing cross-sectional area such that continued pulling of the second end of the suture causes the loop and the captured portion of the suture to be jammed tightly in the tapered binding zone, whereby to bind the suture, and hence the object, to the suture anchor body, which is itself lockingly disposed within the bone.       

     In another form of the present invention, there is provided a method for securing an object to bone, the method comprising: 
     providing an apparatus comprising:
         a suture anchor assembly comprising a suture anchor body and a suture;
           the suture anchor body having an opening formed therein for slidably receiving the suture therethrough;   the suture having a first end, a second end and an intermediate portion extending therebetween;   the suture extending through the opening in the suture anchor body so that the intermediate portion forms a loop on one side of the opening and the first and second ends are disposed on the other side of the opening;   the suture anchor body being configured so that when the suture anchor body is disposed in the hole in the bone, a tapered binding zone is established, the tapered binding zone having a successively decreasing cross-sectional area;   
               

     lockingly positioning the suture anchor body within the hole formed in the bone; 
     passing the first end of the suture through the loop and securingly engaging the object; 
     pulling on the second end of the suture so as to draw the loop and a captured portion of the suture into the tapered binding zone so as to cause the loop and the captured portion of the suture to be jammed tightly in the tapered binding zone, whereby to bind the suture, and hence the object, to the suture anchor body, which is itself lockingly disposed within the bone. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein: 
         FIGS. 1-11  are schematic views showing a first suture anchor assembly formed in accordance with the present invention; 
         FIGS. 11A-11D  are schematic views showing how additional mass and bulk may be added to a portion of the suture in order to enhance locking of the suture; 
         FIGS. 12-14  are schematic views showing a second suture anchor assembly formed in accordance with the present invention; 
         FIGS. 15-17  are schematic views showing a third suture anchor assembly formed in accordance with the present invention; 
         FIGS. 18-20  are schematic views showing a fourth suture anchor assembly formed in accordance with the present invention; 
         FIGS. 21-23  are schematic views showing a fifth suture anchor assembly formed in accordance with the present invention; 
         FIG. 24  is a schematic view showing a sixth suture anchor assembly formed in accordance with the present invention; 
         FIG. 25  is a schematic view showing a seventh suture anchor assembly formed in accordance with the present invention; 
         FIGS. 26-29  and  29 A are schematic views showing an eighth suture anchor assembly formed in accordance with the present invention; 
         FIGS. 30-32  are schematic views showing a ninth suture anchor assembly formed in accordance with the present invention; 
         FIGS. 33 ,  34  and  34 A- 34 C are schematic views showing a tenth suture anchor assembly formed in accordance with the the present invention; 
         FIGS. 35 and 36  are schematic views showing an eleventh suture anchor assembly formed in accordance with the present invention; and 
         FIGS. 37-43  are schematic views showing a twelfth suture anchor assembly formed in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Looking first at  FIGS. 1-5 , there is shown a novel suture anchor assembly  5  which generally comprises a suture anchor body  10  and a suture  15 . Suture anchor assembly  5  may be used to secure soft tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture, and while permitting the surgeon to control the tension with which the soft tissue is secured to bone. 
     More particularly, suture anchor body  10  comprises a generally cylindrical structure having a distal end  20  and a proximal end  25 . The side wall of suture anchor body  10  is provided with a pair of longitudinally-extending, diametrically-opposed recesses  30 ,  35 . 
     Recess  35  preferably increases in depth as it approaches the proximal end of suture anchor body  10 , and shallows in depth as it approaches the distal end of suture anchor body  10 . With the disclosed locking mechanism, for the suture to be locked within the anchor, multiple strands of suture are pulled into an area smaller than the grouping of sutures, thereby causing knotless binding. In one preferred form of the invention, recess  35  has a depth adjacent to the proximal end of suture anchor body  10  which is greater than the thickness of the grouping of suture strands  15 , and a depth adjacent to the distal end of suture anchor body  10  which is less than the thickness of the grouping of suture strands  15 . In  FIGS. 1-5 , recess  35  is shown having a somewhat semi-circular cross-sectional shape, providing tapering in both the longitudinal (i.e., distal to proximal) direction and the lateral direction. In other words, a semi-circular recess  35  provides tapering at both the central portion  35 A of recess  35  as well as at the edges  35 B of recess  35 . However, it should also be appreciated that recess  35  may be formed as a simple inclined flat plane, such that there is tapering in the longitudinal direction but not in the lateral direction. Furthermore, recess  35  may comprise a combination of different cross-sections along its length. 
     One variation to specifically note is providing recess  35  with or without a constant floor depth along the length of the recess, but with lateral walls tapering inwardly towards one another as they extend distally, thereby removing the need to lock suture  15  and loop L between bone B and suture body anchor  10 , but using those surfaces as merely boundaries. See  FIG. 5A . 
     It is also contemplated that variations of side-walled tapering/recess floor tapering may be utilized to effect suture binding. 
     Another variation for the system&#39;s tapering portion may include recess  35  having a constant floor depth for a portion of the recess, with a tapering floor portion (i.e., an inclined floor) for the remainder of recess  35 . By using a combination of tapering sections and non-tapering sections, various cinching/binding areas can be achieved. 
     Recess  30  preferably extends parallel to the central axis of the body, i.e., it has a constant depth along the length of the recess. Recess  30  preferably also has a somewhat semi-circular cross-sectional shape, although it may also be formed as a simple flat plane. 
     A crossbore  40  extends between recesses  30 ,  35 . Crossbore  40  is sized so as to slidingly receive suture  15  as will hereinafter be discussed in further detail. 
     The proximal end of suture anchor body  10  includes an opening  45  for receiving an inserter tool which may be used to deploy suture anchor assembly  5  in bone. Opening  45  is preferably shaped so as to minimize the amount of material removed from the central portion of the suture anchor body, which is where the deepest portion of recess  35  is located. Thus, to this end, where recess  35  and recess  30  have semi-circular cross-sections, opening  45  may be formed with an “hour-glass” (or “figure eight”) cross-section. Additionally, by positioning the largest portions of opening  45  at the periphery of the suture anchor body, the inserter may be provided with matching lobes for driving the suture anchor assembly into bone. This construction can be advantageous, since mating the inserter and the suture anchor body more laterally (i.e., further outboard from the central longitudinal axis of the suture anchor body) provides a longer lever arm which permits more torque to be applied to the portion of the suture anchor body where more material is present. 
     Furthermore, by positioning crossbore  40  and opening  45  remote from one another (i.e., by positioning crossbore  40  at the distal end of the anchor body and positioning opening  45  at the proximal end of the anchor body), more material is available on the proximal end of the anchor body to support the anchor body/inserter interface. Separating the two features (i.e., crossbore  40  and opening  45 ) also provides more material to resist pullout of the suture through the anchor body. 
     If desired, the distal end of suture anchor body  10  may be tapered, e.g., as shown at  50 , so as to facilitate insertion of the suture anchor assembly into bone. 
     Suture  15  comprises a single strand of suture having a leading end (also known as a “pass-thru end”)  55 , a trailing end (also know as a “tightening end”)  60  and an intermediate portion  65  extending therebetween. 
     Looking next at  FIGS. 6-11 , suture anchor assembly  5  may be used in the following manner to secure soft tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture. 
     More particularly, leading end  55  of suture  15  is first placed adjacent to trailing end  60  of suture  15 , thereby forming a loop L in the intermediate portion  65  of suture  15 . Then, loop L is threaded through crossbore  40 , so that leading end  55  and trailing end  60  are disposed in recess  30  on one side of suture anchor body  10  and loop L is disposed in recess  35  on the other side of suture anchor body  10 . See  FIG. 6 . 
     In an alternative embodiment, another transverse hole (not shown) more proximal to transverse hole  40  could be provided in suture anchor body  10 , such that one or both of leads  55  and/or  60  could be directed back to the loop L side of the suture anchor body, i.e., so that one or both of leads  55  and/or  60  could be directed back into recess  35  and brought adjacent to loop L. This approach may be used to consolidate the leads/loop adjacent to one another, or to help increase identification for which leads  55 ,  65  control which function. It should be understood that this feature may also be adapted to other forms of the present invention (see below) where loop L and leads  55 ,  60  are on opposing sides of the suture anchor. 
     Then suture anchor assembly  5  is deployed in a bone B, preferably by advancing the distal end of suture anchor assembly  5  into a bone hole H formed in bone B. See  FIG. 7 . This may be done by mounting the distal end of an inserter I ( FIG. 2 ) in opening  45  in suture anchor body  10 , and simultaneously pulling a slight tension on (i) loop L and (ii) leading end  55  and trailing end  60 , so that suture  15  is seated in recesses  30 ,  35 . Then the inserter is used to push suture anchor assembly  5  into bone hole H. 
     It will be appreciated that inasmuch as the depth of recess  35  decreases adjacent to the distal end of suture anchor body  10 , the gap between the floor of recess  35  and the wall of bone hole H (i.e., the space for receiving suture  15 ) progressively narrows towards the distal end of suture anchor body  10 . In an alternative embodiment, recess  35  could be formed so that it extends substantially parallel to the axis of suture anchor body  10 , but bone hole H might be tapered (see  FIG. 7A ). In either case, it will be appreciated that the space between the floor of recess  35  and the wall of bone hole H progressively narrows towards the distal end of suture anchor body  10 . 
     Next, leading end  55  is passed over (or through) tissue T and then through loop L. See  FIG. 8 . 
     Then, with leading end  55  held under tension, trailing end  60  is pulled. This action causes loop L and a portion  65 A of the suture trailing leading end  55  to be drawn progressively deeper into bone hole H, and hence progressively deeper into the narrowing gap formed between suture anchor body  10  and bone B. See  FIGS. 9-11 . Thus, the more that trailing end  60  is pulled, the farther that loop L and suture portion  65 A is pulled into the narrowing gap between suture anchor body  10  and bone B. Further pulling of trailing end  60  effectively jams loop L and suture portion  65 A between suture anchor body  10  and bone B, thereby binding the suture at this location. This action effectively results in a fixed length  70  of suture  15  extending from loop L, over (or through) tissue T, and then back to loop L, with loop L being locked in position relative to the bone. Thus, by holding leading end  55  of suture  15  under tension and pulling trailing end  60  of suture  15  until loop L is locked in position between suture anchor body  10  and bone B, tissue T can be secured to bone B without requiring the surgeon to tie a knot (or knots) in the suture. 
     Stated differently, suture  15  is secured to bone B by pulling loop L and suture portion  65 A into the narrowing gap formed between suture anchor body  10  and bone B until the suture is effectively jammed in place, thereby forming a knotless fixation. 
     It should be appreciated that it may be possible to improve the binding of suture  15  to bone B by adding mass and bulk to the portion of the suture which is drawn down into the narrowing gap formed between suture anchor body  10  and bone B. See, for example,  FIGS. 11A ,  11 B,  11 C and  11 D. In these examples, additional mass and bulk is added to a portion of suture loop L. This additional mass and bulk helps the suture to more repeatably and controllably lock into the narrowing taper formed between suture anchor body  10  and bone B. In  FIG. 11A , the additional mass and bulk is added by simply pre-knotting (e.g., at the time of manufacture) suture  15  at loop L. In  FIG. 11B , the suture diameter is made thicker by overmolding, weaving or the addition of extra material to the suture, with the particular technique used depending the nature of the suture material and manufacturing preference. Thus, for example, where the suture is braided suture, the additional material may be deposited by overmolding on the braided suture or by additional weaving. Alternatively, where the suture is extruded monofilament, the additional material may be deposited by overmolding. In  FIG. 11C , a bead of material is secured to suture loop L so that the bead of material increases the mass and bulk of the suture. Again, the specific manner in which this is done may depend on suture material and manufacturing preference. Thus, where the suture is braided suture, the bead of material may be strung onto the braided suture and then fixed in place (e.g., by an adhesive). Alternatively, where the suture is monofilament suture, the bead of material may be secured to the suture by overmolding. In  FIG. 11D , a bead of a specific geometry (e.g., non-circular, triangular, rectangular, etc.) is attached to suture loop L. If desired, the specific geometry may be sized and shaped to fit into a specific recess formed within suture anchor body  10  so as to improve suture locking. All of these, and other, approaches add mass and bulk to the suture which aides cinching and securement. It is understood that the bulking features could be rigidly attached to the suture, or the bulking features may merely surround the suture and be free to slide thereon. In this latter respect, it will be appreciated that threading the suture ends through crossbore  40  would effectively capture the free floating bulking feature onto loop L. 
     Additionally, it should be appreciated that all of these suture additions are described as being attached at suture loop L rather than on pass-thru end  55 . These features may be on either, though it is more desirable to include them on the loop L portion since these suture additions do not interfere with passing pass-thru end  55  through tissue (e.g., if the suture additions were placed on pass-thru end  55 , a larger hole would have to be made in the tissue to pass the suture, suture passage might be hindered, etc.). By increasing the bulk of suture loop L, the cinching and securement of the suture may be enhanced and more precisely controlled. 
     Looking next at  FIGS. 12-14 , there is shown a novel suture anchor assembly  75  also formed in accordance with the present invention. Suture anchor assembly  75  is substantially the same as suture anchor assembly  5  discussed above, and is used in substantially the same way, except that (i) crossbore  40  is formed with a narrow throat  40 A and flares outwardly at  40 B as it approaches recess  35 , and (ii) recesses  30  and  35  are formed with a floor which extends generally parallel to the central axis of suture anchor body  10 . By forming crossbore  40  with a narrow throat  40 A which flares outwardly at  40 B as it opens towards recess  35 , a suture binding zone is formed at the intersection of crossbore throat  40 A and crossbore flare  40 B. As a result, when tightening end  60  is pulled, loop L and suture portion  65 A are pulled down into the binding zone created at the intersection of crossbore throat  40 A and crossbore flare  40 B, whereupon they bind, securing the tissue to the bone anchor body and hence to the bone. By forming recesses  30 ,  35  with flat (i.e., non-tapered) floors, suture  15  may be slid more easily into, and out of, crossbore  40 , whereby to facilitate binding loop L and suture portion  65 A at the convergence of crossbore throat  40 A and crossbore flare  40 B. Additionally, corner edgebreaks  40 C, located at the transition points between crossbore  40  and recess  30  and/or recess  35 , may be added in order to reduce the wear of the suture by softening the transition between recesses  30 ,  35  and crossbore  40 . 
     By establishing the narrowing gap of the suture binding zone of suture anchor assembly  75  within crossbore  40  (as opposed to establishing the suture binding zone of suture anchor assembly  5  in the gap between suture anchor body  10  and bone B), a significant benefit may be obtained. More particularly, by creating the narrowing gap of the suture binding zone within crossbore  40 , consistent geometries are provided which ensure binding of the suture with the anchor. In contrast, the external locking (between the anchor body and bone) of suture anchor assembly  5  relies on bone B and bone hole H to be substantially consistent for each use, even though they are potentially variable in nature due to variations in bone quality, patient anatomy, disease, trauma, and the surgical technique used to prepare the bone hole. By providing the suture binding zone in a narrowing crossbore  40 , it is also possible to eliminate the need to carefully size bone hole H relative to suture anchor body  10  in order to ensure proper suture securement. 
     An additional benefit of binding the suture within crossbore  40 , rather than adjacent to the sidewall of suture anchor body, is that the suture anchor assembly can better resist loosening of the soft tissue relative to the bone anchor assembly. This is because the suture binding is located perpendicular to the axis of withdrawal (i.e., the longitudinal axis of the bone hole) rather than parallel to the axis of withdrawal. 
     Furthermore, positioning the binding zone within tapered crossbore  40  provides the bound suture with a surrounding support structure of substantial integrity, thereby making the securement more stable and resisting failure of the suture anchor assembly. 
     Furthermore, if desired, recesses  30  and  35  may be terminated adjacent to crossbore  40 , so that the recesses do not run the full length of the suture anchor body. This construction can help protect the suture during suture anchor insertion, and can provide additional strength at the distal end of the suture anchor body. 
     Looking next at  FIGS. 15-17 , there is shown a novel suture anchor assembly  80  also formed in accordance with the present invention. Suture anchor assembly  80  is substantially the same as suture anchor assembly  75  discussed above, and is used in substantially the same way, except that crossbore  40  has a sweeping taper along its length, whereby to provide a gently narrowing gap of the suture binding zone. Again, this construction can provide a more suture-friendly configuration while still permitting operation of the present invention. 
     Looking next at  FIGS. 18-20 , there is shown a novel suture anchor assembly  85  also formed in accordance with the present invention. Suture anchor assembly  85  is substantially the same as suture anchor assembly  5  discussed above, and is used in substantially the same way, except that recess  35  includes a plurality of ribs  90 . Ribs  90  help resist proximal movement of loop L and suture portion  65 A relative to suture anchor body  10 , while not resisting distal movement of loop L and suture portion  65 A relative to suture anchor body  10 . 
     In addition, as shown in  FIGS. 18-20 , a rounded corner  25 A may be provided at the transition point between the proximal surface of the suture anchor body and recess  35  (and also recess  30 , if desired) so as to soften the transition out of recess  35  (and also recess  30 , if desired) and thereby reduce wear and abrasion of suture  15 . 
     Looking next at  FIGS. 21-23 , there is shown a novel suture anchor assembly  95  also formed in accordance with the present invention. Suture anchor assembly  95  is substantially the same as suture anchor assembly  5  discussed above, and is used in substantially the same way, except that suture anchor body  10  comprises a plurality of surface ridges  100 . Surface ridges  100  help resist proximal movement of suture anchor body  10  relative to the bone, while not resisting distal movement of suture anchor body  10  into bone hole H. In this specific embodiment, ridges  100  are formed by intersecting clockwise and counter-clockwise helical cuts. The resolution of the ridges, the ridge root width, and angle of incidence between the ridges is controlled by the pitch on the helical cuts and the number of leads. In the case where finer engagement with bone is required, a finer pitch can be used; in the case where coarser engagement with bone is required, coarser pitches may be used to increase engagement with the bone. To increase or decrease root width, less or more leads can be used to increase or decrease the distance between two adjacent cuts, accordingly. 
     The geometry of the cuts is important for enhancing bone engagement. As shown in  FIGS. 21-23 , the cuts are preferably substantially perpendicular to the body of the suture anchor on the proximal side of the ridges but are substantially tapered on the distal portion of the ridges. The perpendicular proximal side enhances gripping of the bone while the tapered distal portion facilitates slipping the device past the bone for ease of insertion into bone hole H. The geometry of the helical sweeps can be varied so as to increase grip on the bone or to ease insertion through the bone, for instance by making the proximal side of the ridge undercut relative to a perpendicular cut as shown. 
     Looking next at  FIG. 24 , there is shown a novel suture anchor assembly  105  also formed in accordance with the present invention. Suture anchor assembly  105  is substantially the same as suture anchor assembly  95  discussed above, and is used in substantially the same way, except that ribs  90  are provided in recess  35 . 
     Looking next at  FIG. 25 , there is shown a novel suture anchor assembly  110  also formed in accordance with the present invention. Suture anchor assembly  110  is substantially the same as suture anchor assembly  105  discussed above, and is used in substantially the same way, except that it provides a rounded distal tip  115  to suture anchor body  10 . This construction provides suture anchor body  10  with a distal tip which facilitates insertion into the bone hole. Of course, it is also possible to provide many other distal end geometries of the sort well known in the art to aid in the insertion of the suture anchor body into bone, e.g., such as breaking the distal end, providing a generously rounded lead-in or tapered portion, or providing any other feature that incorporates a reduced cross-section tip for more easily locating the anchor in the prepared hole. 
     Looking next at  FIGS. 26-29  and  FIG. 29A , there is shown a novel suture anchor assembly  120  also formed in accordance with the present invention. Suture anchor assembly  120  generally comprises a suture anchor body  125  and a suture  15 . Suture anchor assembly  120  may be used to secure soft tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture. 
     More particularly, suture anchor body  125  comprises a generally cylindrical structure having a distal end  130  and a proximal end  135 . A tapered lumen  140  extends from distal end  130  to proximal end  135 . More particularly, lumen  140  tapers inwardly as it extends distally along suture anchor body  125 . Thus, and as will hereinafter be discussed in further detail, the gap between the opposing walls of tapered lumen  140  progressively narrows towards the distal end of suture anchor body  125 . Preferably a side opening  145  is formed in suture anchor body  125  near the proximal end of the anchor body, and/or a side opening  150  is formed in suture anchor body  125  near the distal end of the anchor body. 
     It should be appreciated that the tapered portion of tapered lumen  140  may extend the entire length of tapered lumen  140  or along only a portion (or portions) of tapered lumen  140 . Thus, for example, the tapered portion of tapered lumen  140  may be disposed between two cylindrical sections, or it may be located distal of a proximal cylindrical section, or it may be located proximal of a distal cylindrical section. Additionally, tapered lumen  140  could comprise a step-like combination of tapered and cylindrical portions (i.e., like stairs). These configurations can help improve sliding of suture  15  within tapered lumen  140  and to help ensure that the locking portion of the suture will come to rest adjacent to a specific section of the suture anchor body (e.g., a portion of the suture anchor body having a more substantial cross-section so as to provide increased body strength, or an area with internal features for interlocking with the suture, etc.). 
     As previously described, suture  15  comprises a single strand of suture having a leading end  55 , a trailing end  60  and an intermediate portion  65  therebetween. 
     Suture anchor assembly  120  may be used as follows to secure soft tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture. 
     More particularly, leading end  55  of suture  15  is first placed adjacent to trailing end  60  of suture  15 , thereby forming a loop L in the intermediate portion  65  of suture  15 . Then, leading end  55  and trailing end  60  are threaded down tapered lumen  140 , out the distal end of tapered lumen  140 , up the exterior of suture anchor body  125 , into side opening  145 , back into tapered lumen  140  and then out the proximal end of suture anchor body  125 . See  FIG. 26 . If desired, a trough or groove may be provided on the exterior surface of suture anchor body  125  to receive the suture between openings  140  and  145 . This can help protect the suture from wear and abrasion from the surrounding bone during insertion and/or during sliding of the suture (e.g., during securement and/or adjustment). 
     Then suture anchor assembly  120  is deployed in a bone, preferably by advancing distal end  130  of suture anchor body  125  into a hole formed in the bone. This may be done by mounting the distal end of an inserter I ( FIG. 29A ) into tapered lumen  140  of suture anchor body  125 , simultaneously pulling a slight tension on (i) loop L and (ii) leading end  55  and trailing end  60 , so that suture  15  is drawn taut around the distal end of suture anchor body  125 . Then the inserter is used to push suture anchor assembly  120  into the bone hole. 
     Next, leading end  55  is passed over (or through) tissue and then through loop L. 
     Then, with leading end  55  held under tension, trailing end  60  is pulled. This action causes loop L and intermediate portion  65  of suture  15  to be drawn into, and then progressively deeper into, tapered lumen  140 . However, as indicated above, the gap between the opposing walls of tapered lumen  140  (i.e., the space for receiving suture  15 ) progressively narrows along the length of suture anchor body  125 . Thus, the more that trailing end  60  of suture  15  is pulled, the farther that loop L and suture mid-section  65  is pulled into the narrowing gap between the opposing side walls of tapered lumen  140 . Pulling of trailing end  60  continues until loop L and suture mid-section  65  are effectively jammed between the opposing side walls of tapered lumen  140 , thereby binding the suture at this location. This action effectively results in a fixed length of suture  15  extending from loop L, over (or through) the tissue, and then back to loop L, with loop L being locked in position relative to the anchor body and hence to the bone. Thus, by holding leading end  55  under tension and pulling trailing end  60  until loop L and the suture mid-section  65  are locked, the tissue can be secured to the bone without requiring the surgeon to tie a knot (or knots) in the suture. 
     If desired, suture  15  can be passed through side opening  150  instead of side opening  145 . However, passing the suture external to the anchor through the more proximal opening  145  (rather than the more distal opening  150 ) can provide a variety of benefits, including providing additional bulk to the anchor body leading to improved anchoring to bone and smoother flow of the sutures. On the other hand, passing the sutures through the more distal opening  150  (rather than the more proximal opening  145 ) can help limit the exposure of the suture to the bone, thereby reducing potential damage to the suture. 
     It may also be beneficial to place the suture pass-thru hole (e.g., side openings  145 ,  150 , etc.) on other locations in the anchor body so as to better protect the suture, better secure the anchor to the bone, improve the suture securement, etc. 
     Looking next at  FIGS. 33 and 34 , there is shown a novel suture anchor assembly  165  also formed in accordance with the present invention. Suture anchor assembly  165  is substantially the same as suture anchor assembly  120  discussed above, except that (i) side openings  145 ,  150  are omitted, (ii) a crosspin  170  is formed at the distal end of tapered lumen  140 , (iii) a shoulder  152  is formed within tapered lumen  140  proximal to crosspin  170 , and (iv) (ribs  175  are formed on the exterior of suture anchor body  125 . Furthermore, suture  15  is threaded into suture anchor body  125  by threading leading end  55  and trailing end  60  down tapered lumen  140 , around crosspin  170 , then back up tapered lumen  140  and out the proximal end of suture anchor body  125 . 
     Suture anchor assembly  155  is used in substantially the same way as suture anchor assembly  120 , i.e., after the suture anchor body is disposed in the bone, leading end  55  of suture  15  is passed over (or through) the tissue to be captured, through loop L and then, while leading end  55  is held under tension, trailing end  60  is pulled so as to draw loop L and a new portion of the suture mid-section  65  down tapered lumen  140  until loop L and suture mid-section  65  are locked in position. In this way, suture anchor assembly  155  can be used to secure tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture. Also, as suture  15  is tensioned, it could pull inward tabs  163  that extend distal to holes  145  and  150  in suture anchor body  125 , further locking suture  15  within tapered lumen  140  of the device. 
     Looking next at  FIGS. 33 and 34 , there is shown a novel suture anchor assembly  165  also formed in accordance with the present invention. Suture anchor assembly  165  is substantially the same as suture anchor assembly  120  discussed above, except that (i) side openings  145 ,  150  are omitted, (ii) a crosspin  170  is formed at the distal end of tapered lumen  140 , (iii) a shoulder  152  is formed within tapered lumen  140  proximal to crosspin  170 , and (iv) ribs  175  are formed on the exterior of suture anchor body  125 . Furthermore, suture  15  is threaded into suture anchor body  125  by threading leading end  55  and trailing end  60  down tapered lumen  140 , around crosspin  170 , then back up tapered lumen  140  and out the proximal end of suture anchor body  125 . 
     Features such as ribs  175  may be added to exterior surfaces of the suture anchor body so as to improve the grip of the suture anchor body on the bone. Other external features may also be used, e.g., threads, opposing threads, bumps, textures, ridges, discontinuous features, etc. and then, while leading end  55  is held under tension, 
     Suture anchor assembly  165  is used in substantially the same way as suture anchor assembly  120 , i.e., after the suture anchor body is disposed in the bone, leading end  55  of suture  15  is passed over (or through) the tissue to be captured (FIG.  34 A), through loop L ( FIG. 34B ) and then, while leading end  55  is held under tension, trailing end  60  is pulled so as to draw loop L and suture mid-section  65  down tapered lumen  140  until loop L and suture mid-section  65  are locked in position ( FIG. 34C ). In this way, suture anchor assembly  155  can be used to secure tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture. 
     Looking next at  FIGS. 35 and 36 , there is shown a novel suture anchor assembly  180  also formed in accordance with the present invention. Suture anchor assembly  180  is substantially the same as suture anchor assembly  165  discussed above, except that tapered lumen  140  is a blind hole terminating proximal to the distal end of suture anchor body  125  so as to provide a distal end wall  185 , and at least two openings  190 ,  195  are formed through the distal end wall. Furthermore, suture  15  is threaded into suture anchor body  125  by threading leading end  55  and trailing end  60  down tapered lumen  140 , out of an opening (e.g., opening  195 ), along the exterior of the distal end wall, into an opening (e.g., opening  190 ), and then back up tapered lumen  140  and out the proximal end of suture anchor body  125 . A trough or groove to connect openings  195  and  190  may be provided so as to protect the suture, especially during insertion into bone. 
     Suture anchor assembly  180  is used in substantially the same way as suture anchor assembly  165 , i.e., after the suture anchor body is disposed in the bone, leading end  55  of suture  15  is passed over (or through) the tissue to be captured, through loop L and then, while leading end  55  is held under tension, trailing end  60  is pulled so as to draw loop L and suture mid-section  65  down tapered lumen  140  until loop L and suture mid-section  65  are locked in position. In this way, suture anchor assembly  155  can be used to secure tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture. 
     Looking next at  FIGS. 37-43 , there is shown a novel suture anchor assembly  200  also formed in accordance with the present invention. Suture anchor assembly  200  is substantially the same as suture anchor assembly  185  discussed above, except that four openings are formed through the distal end wall, the suture follows a slightly different path, and the exterior of suture anchor body  125  may be formed without ribs. However, it should be understood that with suture anchor assembly  200  (and also with suture anchor assembly  180 , etc.) there are a multitude of external features that may or may not be included for the purpose of enhancing fixation of the anchor body to bone. For example, the opposing helical cuts (such as shown in suture anchor assembly  95 ) are such a feature. Ribs, bumps and other texturing features may also be included. Suture anchor assembly  200  generally comprises a suture anchor body  125  and a suture  15 . Suture anchor assembly  200  may be used to secure soft tissue to bone without requiring the formation of a knot (or knots). 
     Suture anchor body  125  comprises a generally tapered structure having a distal end  130  and a proximal end  135 . A tapered lumen  140  extends from distal end  130  to proximal end  135 . More particularly, tapered lumen  140  tapers inwardly as it extends distally along suture anchor body  125 . Thus, and as will hereinafter be discussed in further detail, the gap between the opposing walls of tapered lumen  140  progressively narrows towards the distal end of suture anchor body  125 . Preferably four openings  205 ,  210 ,  215 ,  220  are formed in the distal end wall of suture anchor body  125 . 
     Suture  15  comprises a single strand of suture having a leading end  55 , a trailing end  60  and an intermediate portion  65  therebetween. 
     More particularly, leading end  55  of suture  15  is first placed adjacent to trailing end  60  of suture  15 , thereby forming a loop L in intermediate portion  65  of suture  15 . Then, leading end  55  is passed down tapered lumen  140 , out of opening  205 , across the exterior of the distal end wall, into opening  210 , back up tapered lumen  140  and then out the proximal end of suture anchor body  125 . Then, trailing end  60  is passed down tapered lumen  140 , out of opening  215 , across the exterior of the distal end wall, into opening  220 , back up tapered lumen  140  and then out the proximal end of suture anchor body  125 . See  FIG. 38 . 
     Then suture anchor assembly  200  is deployed in a bone, preferably by advancing distal end  130  of suture anchor assembly  200  into a hole formed in the bone. This may be done by mounting the distal end of an inserter (not shown) into tapered lumen  140  of suture anchor body  125 , pulling a slight tension on loop L, and leading end  55  and trailing end  60 , so that suture  15  is drawn taut around the distal end of suture anchor body  125 . Then the inserter is used to push suture anchor assembly  200  into the bone hole. See  FIG. 40 . 
     Next, leading end  55  is passed over (or through) tissue T (see  FIG. 41 ) and then through loop L (see  FIG. 42 ). 
     Then, with leading end  55  held under tension, trailing end  60  is pulled. This action causes loop L and intermediate portion  65  to be drawn into, and then progressively deeper into, tapered lumen  140  which has progressively narrowing cross-section. See  FIG. 43 . The more that trailing end  60  is pulled, the farther that loop L and suture mid-section  65  are pulled into the narrowing gap between the opposing side walls of tapered lumen  140  eventually jamming all of the suture between the opposing side walls of tapered lumen  140 , thereby binding the suture at this location. This action effectively results in a fixed length of suture  15  extending from loop L, over (or through) tissue T, and then back to loop L, with loop L being locked in position relative to the anchor body and hence the bone. Thus, by holding leading end  55  under tension and pulling trailing end  60  until loop L and suture mid-section  65  are locked, tissue T can be secured to the bone without requiring the surgeon to tie a knot (or knots) in the suture. 
     Thus it will be seen that the present invention provides a novel suture anchor which may be used to secure soft tissue to bone without requiring the surgeon to tie a knot (or knots) in the suture. 
     Clinical Applications 
     In the foregoing discussion, the present invention is discussed in the general context of being used to secure soft tissue to bone. 
     In preferred clinical applications, the present invention may be used to secure a ligament to bone, a tendon to bone, a labrum to the acetabulum, etc. In essence, the present invention may be used to secure substantially any soft tissue to any bone. 
     It should also be appreciated that the present invention may be used to secure objects other than soft tissue to bone. By way of example but not limitation, the present invention may be used to secure an implant to bone. 
     Thus it will be seen that the present invention may be used to secure substantially any object to substantially any bone. 
     Modifications of the Preferred Embodiments 
     It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.