Abstract:
A system for securing soft tissue to bone, the system comprising:
       a center post anchor comprising a body adapted for disposition in bone and having a retention element thereon for retaining the body in bone, the center post anchor comprising a suture having a first portion secured to the body and a second portion residing free of the body and adapted to be passed through the soft tissue which is to be secured to the bone; and   a bridge post anchor comprising a body adapted for disposition in bone and having a retention element thereon for retaining the body in bone, the bridge post anchor including a capture element for capturing the second portion of the suture to the bone, such that when the center post anchor is disposed in bone and the second portion of the suture extends through in bone can secure the soft tissue to the bone.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATION 
       [0001]    This patent application claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 60/994,576, filed Sep. 20, 2007 by Brian Kelly et al. for METHOD AND APPARATUS FOR RE-ATTACHING THE LABRUM OF A HIP JOINT (Attorney&#39;s Docket No. FIAN-9 PROV), which patent application is hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to surgical methods and apparatus in general, and more particularly to methods and apparatus for treating the hip joint. 
       BACKGROUND OF THE INVENTION 
     The Hip Joint in General 
       [0003]    The hip joint is a ball-and-socket joint which movably connects the leg to the torso. The hip joint is capable of a wide range of different motions, e.g., flexion and extension, abduction and adduction, medial and lateral rotation, etc. See  FIGS. 1A ,  1 B,  1 C and  1 D. 
         [0004]    With the possible exception of the shoulder joint, the hip joint is perhaps the most mobile joint in the body. Significantly, and unlike the shoulder joint, the hip joint carries substantial weight loads during most of the day, in both static (e.g., standing and sitting) and dynamic (e.g., walking and running) conditions. 
         [0005]    The hip joint is susceptible to a number of different pathologies. These pathologies can have both congenital and injury-related origins. In some cases, the pathology can be substantial at the outset. In other cases, the pathology may be minor at the outset but, if left untreated, may worsen over time. More particularly, in many cases, an existing pathology may be exacerbated by the dynamic nature of the hip joint and the substantial weight loads imposed on the hip joint. 
         [0006]    The pathology may, either initially or thereafter, significantly interfere with patient comfort and lifestyle. In some cases, the pathology can be so severe as to require partial or total hip replacement. A number of procedures have been developed for treating hip pathologies short of partial or total hip replacement, but these procedures are generally limited in scope due to the significant difficulties associated with treating the hip joint. 
         [0007]    A better understanding of various hip joint pathologies, and also the current limitations associated with their treatment, can be gained from a more thorough understanding of the anatomy of the hip joint. 
       Anatomy of the Hip Joint 
       [0008]    The hip joint is formed at the junction of the femur and the hip. More particularly, and looking now at  FIG. 2 , the ball of the femur is received in the acetabular cup of the hip, with a plurality of ligaments and other soft tissue serving to hold the bones in articulating condition. 
         [0009]    More particularly, and looking now at  FIG. 3 , the femur is generally characterized by an elongated body terminating, at its top end, in an angled neck which supports a hemispherical head (also sometimes referred to as “the ball”). As seen in  FIGS. 3 and 4 , a large projection known as the greater trochanter protrudes laterally and posteriorly from the elongated body adjacent to the neck of the femur. A second, somewhat smaller projection known as the lesser trochanter protrudes medially and posteriorly from the elongated body adjacent to the neck. An intertrochanteric crest ( FIGS. 3 and 4 ) extends along the periphery of the femur, between the greater trochanter and the lesser trochanter. 
         [0010]    Looking next at  FIG. 5 , the hip socket is made up of three constituent bones: the ilium, the ischium and the pubis. These three bones cooperate with one another (they typically ossify into a single “hip bone” structure around the age of 25 or so) so as to collectively form the acetabular cup. The acetabular cup receives the head of the femur. 
         [0011]    Both the head of the femur and the acetabular cup are covered with a layer of articular cartilage which protects the underlying bone and facilitates motion. See  FIG. 6 . 
         [0012]    Various ligaments and soft tissue serve to hold the ball of the femur in place within the acetabular cup. More particularly, and looking now at  FIGS. 7 and 8 , the ligamentum teres extends between the ball of the femur and the base of the acetabular cup. As seen in  FIG. 9 , a labrum is disposed about the perimeter of the acetabular cup. The labrum serves to increase the depth of the acetabular cup and effectively establishes a suction seal between the ball of the femur and the rim of the acetabular cup, thereby helping to hold the head of the femur in the acetabular cup. In addition to the foregoing, and looking now at  FIG. 10 , a fibrous capsule extends between the neck of the femur and the rim of the acetabular cup, effectively sealing off the ball-and-socket members of the hip joint from the remainder of the body. The foregoing structures (i.e., the ligamentum teres, the labrum and the fibrous capsule) are encompassed and reinforced by a set of three main ligaments (i.e., the iliofemoral ligament, the ischiofemoral ligament and the pubofemoral ligament) which extend between the femur and the perimeter of the hip socket. See  FIGS. 11 and 12 . 
       Pathologies of the Hip Joint 
       [0013]    As noted above, the hip joint is susceptible to a number of different pathologies. These pathologies can have both congenital and injury-related origins. 
         [0014]    By way of example but not limitation, one important type of congenital pathology of the hip joint involves impingement between the neck of the femur and the rim of the acetabular cup. In some cases, and looking now at  FIG. 13 , this impingement can occur due to irregularities in the geometry of the femur. This type of impingement is sometimes referred to as a cam-type femoroacetabular impingement (i.e., a cam-type FAI). In other cases, and looking now at  FIG. 14 , the impingement can occur due to irregularities in the geometry of the acetabular cup. This latter type of impingement is sometimes referred to as a pincer-type femoroacetabular impingement (i.e., a pincer-type FAI). Impingement can result in a reduced range of motion, substantial pain and, in some cases, significant deterioration of the hip joint. 
         [0015]    By way of further example but not limitation, another important type of congenital pathology of the hip joint involves defects in the articular surface of the ball and/or the articular surface of the acetabular cup. Defects of this type sometimes start fairly small but often increase in size over time, generally due to the dynamic nature of the hip joint and also due to the weight-bearing nature of the hip joint. Articular defects can result in substantial pain, induce and/or exacerbate arthritic conditions and, in some cases, cause significant deterioration of the hip joint. 
         [0016]    By way of further example but not limitation, one important type of injury-related pathology of the hip joint involves trauma to the labrum. More particularly, in many cases, an accident or sports-related injury can result in the labrum being torn away from the rim of the acetabular cup, typically with a tear running through the body of the labrum. See  FIG. 15 . These types of injuries can be very painful for the patient and, if left untreated, can lead to substantial deterioration of the hip joint. 
       The General Trend Toward Treating Joint Pathologies Using Minimally-Invasive, and Earlier, Interventions 
       [0017]    The current trend in orthopedic surgery is to treat joint pathologies using minimally-invasive techniques. Such minimally-invasive, “keyhole” surgeries generally offer numerous advantages over traditional, “open” surgeries, including reduced trauma to tissue, less pain for the patient, faster recuperation times, etc. 
         [0018]    By way of example but not limitation, it is common to re-attach ligaments in the shoulder joint using minimally-invasive, “keyhole” techniques which do not require laying open the capsule of the shoulder joint. By way of further example but not limitation, it is common to repair torn meniscal cartilage in the knee joint, and/or to replace ruptured ACL ligaments in the knee joint, using minimally-invasive techniques. 
         [0019]    While such minimally-invasive approaches can require additional training on the part of the surgeon, such procedures generally offer substantial advantages for the patient and have now become the standard of care for many shoulder joint and knee joint pathologies. 
         [0020]    In addition to the foregoing, in view of the inherent advantages and widespread availability of minimally-invasive approaches for treating pathologies of the shoulder joint and knee joint, the current trend is to provide such treatment much earlier in the lifecycle of the pathology, so as to address patient pain as soon as possible and so as to minimize any exacerbation of the pathology itself. This is in marked contrast to traditional surgical practices, which have generally dictated postponing surgical procedures as long as possible so as to spare the patient from the substantial trauma generally associated with invasive surgery. 
       Treatment for Pathologies of the Hip Joint 
       [0021]    Unfortunately, minimally-invasive treatments for pathologies of the hip joint have lagged far behind minimally-invasive treatments for pathologies of the shoulder joint and knee joint. This is generally due to (i) the constrained geometry of the hip joint itself, and (ii) the nature and location of the pathologies which must typically be addressed in the hip joint. 
         [0022]    More particularly, the hip joint is generally considered to be a “tight” joint, in the sense that there is relatively little room to maneuver within the confines of the joint itself. This is in marked contrast to the shoulder joint and the knee joint, which are generally considered to be relatively “spacious” joints (at least when compared to the hip joint). As a result, it is relatively difficult for surgeons to perform minimally-invasive procedures on the hip joint. 
         [0023]    Furthermore, the pathways for entering the interior of the hip joint (i.e., the pathways which exist between adjacent bones) are generally much more constraining for the hip joint than for the shoulder joint or the knee joint. This limited access further complicates effectively performing minimally-invasive procedures on the hip joint. 
         [0024]    In addition to the foregoing, the nature and location of the pathologies of the hip joint also complicate performing minimally-invasive procedures on the hip joint. By way of example but not limitation, consider a typical detachment of the labrum in the hip joint. In this situation, instruments must generally be introduced into the joint space using an angle of approach which is set at approximately a right angle to the angle of re-attachment. This makes drilling into bone, for example, much more complicated than where the angle of approach is effectively aligned with the angle of re-attachment, such as is frequently the case in the shoulder joint. Furthermore, the working space within the hip joint is typically extremely limited, further complicating repairs where the angle of approach is not aligned with the angle of re-attachment. 
         [0025]    As a result of the foregoing, minimally-invasive hip joint procedures are still relatively difficult to perform and relatively uncommon in practice. Consequently, patients are typically forced to manage their hip pain for as long as possible, until a resurfacing procedure or a partial or total hip replacement procedure can no longer be avoided. These procedures are generally then performed as a highly-invasive, open procedure, with all of the disadvantages associated with highly-invasive, open procedures. 
         [0026]    As a result, there is, in general, a pressing need for improved methods and apparatus for treating pathologies of the hip joint. 
       Re-Attaching the Labrum of the Hip Joint 
       [0027]    As noted above, hip arthroscopy is becoming increasingly more common in the diagnosis and treatment of various hip pathologies. However, due to the anatomy of the hip joint and the pathologies associated with the same, hip arthroscopy is currently practical for only selected pathologies and, even then, hip arthroscopy has generally met with limited success. 
         [0028]    One procedure which is sometimes attempted arthroscopically relates to the repair of a torn and/or detached labrum. This procedure may be attempted (i) when the labrum has been damaged but is still sufficiently healthy and intact as to be capable of repair and/or re-attachment, and (ii) when the labrum has been deliberately detached (e.g., so as to allow for acetabular rim trimming to treat a pathology such as a pincer-type FAI) and needs to be subsequently re-attached. See, for example,  FIG. 16 , which shows a normal labrum L secured to the acetabulum A, and  FIG. 17 , which shows labrum L detached from acetabulum A. In this respect it should also be appreciated that repairing the labrum rather than removing the labrum is generally desirable, inasmuch as studies have shown that patients whose labrum has been repaired tend to have better long-term outcomes than patients whose labrum has been removed. 
         [0029]    Unfortunately, current methods and apparatus for arthroscopically re-attaching the labrum are somewhat problematic. The present invention is intended to improve upon the current approaches for labrum re-attachment. 
         [0030]    More particularly, current approaches for arthroscopically re-attaching the labrum typically use apparatus originally designed for use in re-attaching ligaments to bone. For example, one such approach utilizes a screw-type bone anchor, with two sutures extending therefrom, and involves deploying the bone anchor in the acetabulum above the labrum re-attachment site. A first one of the sutures is passed either through the detached labrum or, alternatively, around the detached labrum. Then the first suture is tied to the second suture so as to support the labrum against the acetabular rim. 
         [0031]    Since the suture knot typically stands proud of the adjacent tissue, the surgeon generally tries to position the knot above the acetabular rim, exterior to the articulating surface of the hip joint, so as to avoid abrasion during hip motion. However, this can be difficult to achieve, given the limited space within the hip joint, the angle of approach dictated by the patient&#39;s anatomy, etc. Indeed, the mere act of arthroscopically tying a suture knot can be relatively complex and time-consuming. Thus, the need to precisely position the knot outside the articulating portion of the joint can further complicate an already-difficult arthroscopic procedure. 
         [0032]    Accordingly, a primary object of the present invention is to simplify the foregoing procedure by providing a new approach for arthroscopically re-attaching the labrum to the acetabulum. 
       SUMMARY OF THE INVENTION 
       [0033]    The present invention provides a new approach for arthroscopically re-attaching the labrum to the acetabulum. 
         [0034]    Significantly, this new approach does not require the tying of knots in order to re-attach the labrum to the acetabulum. 
         [0035]    More particularly, the present invention provides a novel method and apparatus for knotlessly re-attaching the labrum to the acetabulum. As a result, the present invention provides a simpler, faster and more convenient approach for securing the labrum to the acetabulum. 
         [0036]    In one preferred form of the present invention, there is provided a system for securing soft tissue to bone, the system comprising: 
         [0037]    a center post anchor comprising a body adapted for disposition in bone and having a retention element thereon for retaining the body in bone, the center post anchor comprising a suture having a first portion secured to the body and a second portion residing free of the body and adapted to be passed through the soft tissue which is to be secured to the bone; and 
         [0038]    a bridge post anchor comprising a body adapted for disposition in bone and having a retention element thereon for retaining the body in bone, the bridge post anchor including a capture element for capturing the second portion of the suture to the bone, such that when the center post anchor is disposed in bone and the second portion of the suture extends through the soft tissue, disposition of the bridge post anchor in bone can secure the soft tissue to the bone. 
         [0039]    In another form of the present invention, there is provided a method for securing soft tissue to bone, the method comprising: 
         [0040]    providing a system comprising:
       a center post anchor comprising a body adapted for disposition in bone and having a retention element thereon for retaining the body in bone, the center post anchor comprising a suture having a first portion secured to the body and a second portion residing free of the body and adapted to be passed through the soft tissue which is to be secured to the bone; and   a bridge post anchor comprising a body adapted for disposition in bone and having a retention element thereon for retaining the body in bone, the bridge post anchor including a capture element for capturing the second portion of the suture to the bone, such that when the center post anchor is disposed in bone and the second portion of the suture extends through the soft tissue, disposition of the bridge post anchor in bone can secure the soft tissue to the bone;       
 
         [0043]    inserting the center post anchor into the bone; 
         [0044]    passing the second portion of the suture through the soft tissue; 
         [0045]    cinching the suture so as to draw the soft tissue against the bone; and 
         [0046]    securing the second portion of the suture to the bone by inserting the bridge post anchor into the bone, with the capture element capturing the second portion of the suture to the bone. 
         [0047]    In another form of the present invention, there is provided a system for attaching soft tissue to bone, the system comprising: 
         [0048]    a center post anchor comprising a body having a distal end and a proximal end, a pair of legs extending distally from the distal end of the body and separated by a slot, the legs tapering outwardly along their length so that the center post anchor has a diameter at the legs which is larger than the diameter at the body, with the legs being inwardly compressible, and a suture attached to the proximal end of the body, the suture having at least one free end associated therewith; and 
         [0049]    at least one bridge post anchor comprising a body having a distal end and a proximal end, and a pair of legs extending from the distal end of the body and separated by a slot, the legs tapering outwardly along their length so that the bridge post anchor has a diameter at the legs which is larger than the diameter at the body, with the legs being inwardly compressible; 
         [0050]    such that the center post anchor can be secured in a hole in a bone by compressing its legs inwardly, deploying the center post anchor in the bone and releasing its legs so that they thereafter engage the bone, whereby to secure the suture to the bone; 
         [0051]    and further such that the bridge post anchor can capture the free end of the suture to bone by positioning the free end of the suture in the slot, compressing the legs of the bridge post anchor inwardly, positioning the bridge post anchor in a hole in the bone, and releasing its legs so that they thereafter engage the bone. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0052]    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 invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein: 
           [0053]      FIGS. 1A-1D  are schematic views showing various aspects of hip motion; 
           [0054]      FIG. 2  is a schematic view showing the bone structure in the region of the hip joints; 
           [0055]      FIG. 3  is a schematic view of the femur; 
           [0056]      FIG. 4  is a schematic view of the top end of the femur; 
           [0057]      FIG. 5  is a schematic view of the pelvis; 
           [0058]      FIGS. 6-12  are schematic views showing the bone and soft tissue structure of the hip joint; 
           [0059]      FIG. 13  is a schematic view showing cam-type femoroacetabular impingement (FAI); 
           [0060]      FIG. 14  is a schematic view showing pincer-type femoroacetabular impingement (FAI); 
           [0061]      FIG. 15  is a schematic view showing a labral tear; 
           [0062]      FIG. 16  is a schematic view showing the labrum attached to the acetabulum; 
           [0063]      FIG. 17  is a schematic view showing the labrum detached from the acetabulum; 
           [0064]      FIG. 18  is a schematic view showing a novel anchoring system formed in accordance with the present invention, wherein the anchoring system comprises a center post anchor and a pair of bridge post anchors; 
           [0065]      FIG. 19  is a schematic view showing further details of the center post anchor of  FIG. 18 ; 
           [0066]      FIG. 20  is a schematic view showing further details of a bridge post anchor of  FIG. 18 ; 
           [0067]      FIGS. 21-23  are schematic views showing the anchoring system of  FIG. 18  being used to re-attach the labrum to the acetabulum; 
           [0068]      FIG. 23A  is a schematic view showing another center post anchor formed in accordance with the present invention; 
           [0069]      FIG. 23B  is a schematic view showing another bridge post anchor formed in accordance with the present invention; 
           [0070]      FIGS. 24 and 25  are schematic views showing still another bridge post anchor formed in accordance with the present invention; 
           [0071]      FIGS. 26-29  are schematic views showing operation of the bridge post anchor of  FIGS. 24 and 25 ; 
           [0072]      FIGS. 29A and 29B  show alternative constructions for the bridge post anchor; and 
           [0073]      FIG. 30  is a schematic view showing yet another bridge post anchor formed in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0074]    Looking now at  FIG. 18 , there is shown novel anchoring system  5  for re-attaching the labrum to the acetabulum. This novel anchoring system  5  generally comprises a center post anchor  100  and a pair of bridge post anchors  200 . 
         [0075]    Looking next at  FIG. 19 , center post anchor  100  generally comprises a body  105  having a distal end  110  and a proximal end  115 . A pair of legs  120  extend distally from distal end  110  of body  105 . Legs  120  are separated by a slot  125 . Legs  120  taper outwardly along their length, so that center post anchor  100  has a diameter at legs  120  which is somewhat larger than the diameter of body  105 . Legs  120  have a selected degree of resiliency, such that the distal ends of legs  120  can be compressed inboard when desired, so that legs  120  can have a combined diameter equal to or less than body  105  of center post anchor  100 . A pair of sutures  130  are secured to proximal end  115  of body  105 . Each of sutures  130  has a needle  135  secured to its free end. 
         [0076]    Looking next at  FIG. 20 , each bridge post anchor  200  is preferably identical to center post anchor  100 , except that it does not have sutures  130  and needles  135  secured thereto. More particularly, each bridge post anchor  200  generally comprises a body  205  having a distal end  210  and a proximal end  215 . A pair of legs  220  extend distally from distal end  210  of body  205 . Legs  220  are separated by a slot  225 . Legs  220  taper outwardly along their length, so that bridge post anchor  200  has a diameter at legs  220  which is somewhat larger than the diameter of body  205 . Legs  220  have a selected degree of resiliency, such that the distal ends of legs  220  can be compressed inboard when desired, so that legs  220  can have a combined diameter equal to or less than body  205  of bridge post anchor  200 . 
       Use of Anchoring System  5  to Re-Attach the Labrum to the Acetabulum 
       [0077]    Anchoring system  5  is preferably used as follows to re-attach the labrum to the acetabulum. 
         [0078]    Looking now at  FIG. 21 , a center hole CH is formed in acetabulum A adjacent to the acetabular rim. Then center post anchor  100  is secured in center hole CH. This is done by (i) compressing legs  120  inboard so that legs  120  have a combined diameter equal to or less than body  105  of center post anchor  100 , (ii) inserting center post anchor  100  into center hole CH while its legs are in this inboard position, and (iii) releasing legs  120 , thereby causing legs  120  to engage the side wall of center hole CH and thereby secure center post anchor  100  to acetabulum A. At the same time, sutures  130  extend from proximal end  115  of center post anchor  100 . 
         [0079]    Preferably, the distal ends of legs  120  are beveled inwardly at their peripheries so that engagement of legs  120  with the rim of center hole CH during anchor insertion automatically causes legs  120  to compress inwardly to facilitate entry into center hole CH and thereafter automatically project outwardly so as to grip the surrounding bone. 
         [0080]    Looking next at  FIG. 22 , needles  135  are then used to pass sutures  130  through labrum L. Preferably, each of the sutures  130  is passed through labrum L so that sutures  130  extend out of labrum L laterally from where sutures  130  enter the labrum. As a result, sutures  130  do not project through the articular face AF of labrum L. 
         [0081]    Thereafter, and looking now at  FIG. 23 , a pair of bridge holes BH are formed in acetabulum A, one on each side of center post anchor  100 . Then bridge post anchors  200  are used to secure the free ends of sutures  130  to acetabulum A so as to re-attach labrum L to acetabulum A. More particularly, while holding a suture  130  taut, so as to draw labrum L against acetabulum A, bridge post anchor  200  is moved so as to straddle that suture, with the suture being positioned in anchor slot  225 , against distal end  210  of body  205 . Still holding the suture taut, legs  220  of bridge post anchor  200  are compressed so that legs  220  have a combined diameter equal to or less than body  205  of bridge post anchor  200 , and then bridge post anchor  200  is pressed into bridge hole BH, with distal end  210  of body  205  carrying suture  130  into bridge hole BH. Thereafter, the compression on legs  220  is released whereupon legs  220  engage the side wall of bridge hole BH so as to secure bridge post anchor  200  to acetabulum A. This action has the effect of binding suture  130  to acetabulum A under tension, thereby fixing labrum L to acetabulum A. 
         [0082]    Preferably, the distal ends of legs  220  are beveled inwardly at their peripheries so that engagement of legs  220  with the rim of bridge hole BH during anchor insertion automatically causes legs  220  to compress inwardly to facilitate entry into bridge hole BH and thereafter automatically project outwardly so as to grip the surrounding bone. 
         [0083]    This procedure is then repeated for the remaining suture  130 , i.e., passing suture  130  through labrum L and then knotlessly attaching that suture under tension to acetabulum A using a bridge post anchor  200  so as to secure labrum L to the acetabulum. Then the free ends of the sutures extending out of bridge holes BH (including needles  135 ) are cut away, and the suture ends and needles are removed from the surgical site. 
         [0084]    It will be appreciated that the foregoing labrum re-attachment is effected without the need to tie a knot. As a result, the present invention provides a simpler, faster and more convenient approach for securing the labrum to the acetabulum. 
         [0085]    It should also be appreciated that if it is desired to use only one suture to secure the labrum to the acetabulum, only one of the sutures  130  and needle  135 , and only one bridge post anchor  200 , is used. In this case, the unused suture  130  and needle  135  may be cut away, adjacent to center post anchor  100 . 
         [0086]    Alternatively, where it is desired to use only one suture strand to secure the labrum to the acetabulum, anchoring system  5  may be provided with a center post anchor  100  and only one bridge post anchor  200 . In this construction, center post anchor  100  may be provided with only one suture strand  130  extending therefrom. 
         [0087]    It should also be appreciated that, if desired, an arthroscopic suture passer can be used in place of needles  135  to pass each of sutures  130  through labrum L. By way of example but not limitation, the suture passers described in U.S. Pat. Nos. 5,522,820 and Des. 343,728, and the suture passers described in U.S. Patent Application Publications Nos. 2005/0283171 and 2007/0179510, may be used to pass each of the sutures  130  through labrum L. Where an arthroscopic suture passer is to be used in place of needles  135  to pass suture  130  through labrum L, needles  135  are omitted. 
       Use of a Different Center Post Anchor 
       [0088]    It should also be appreciated that center post anchor  100  may be replaced by another device for anchoring suture to bone. 
         [0089]    By way of example but not limitation, center post anchor  100  may be replaced by a conventional screw-type bone anchor of the sort sold by Depuy Mitek under the trade name SPIRALOK, or a conventional barb-type bone anchor of the sort sold by Depuy Mitek under the trade name GII QUICKANCHOR, or a conventional toggle-type bone anchor of the sort sold by Depuy Mitek under the trade name PANALOK, etc. 
         [0090]    By way of example but not limitation, and looking now at  FIG. 23A , there is shown a center post anchor  100 A which may be used in place of center post anchor  100  described previously. 
         [0091]    More particularly, each center post anchor  100 A generally comprises a body  105 A having a distal end  110 A and a proximal end  115 A. A pair of legs  120 A extend proximally from proximal end  115 A of body  105 A. Legs  120 A taper outwardly along their length, so that center post anchor  100 A has a diameter at legs  120 A which is somewhat larger than the diameter of body  105 A. Legs  120 A have a selected degree of resiliency, such that the proximal ends of legs  120 A can be compressed inboard when desired, so that legs  120 A can have a combined diameter equal to or less than body  105 A of center post anchor  100 A. Sutures  130  are secured to proximal end  115 A of body  105 A. In use, center post anchor  100 A is driven distal end first into center hole CH, with legs  120 A first compressing inboard so as to enter the acetabulum and thereafter expanding outboard so as to secure center post anchor  100 A center hole CH. 
       Use of a Different Bridge Post Anchor 
       [0092]    It should also be appreciated that bridge post anchor  200  may be replaced by another device for anchoring suture to bone. 
         [0093]    By way of example but not limitation, and looking now at  FIG. 23B , there is shown a bridge post anchor  200 B which may be used in place of bridge post anchor  200  described previously. 
         [0094]    More particularly, each bridge post anchor  200 B generally comprises a body  205 B having a distal end  210 B and a proximal end  215 B. A pair of legs  220 B extend proximally from proximal end  215 B of body  205 B. Legs  220 B taper outwardly along their length, so that bridge post anchor  200 B has a diameter at legs  220 B which is somewhat larger than the diameter of body  205 B. Legs  220 B have a selected degree of resiliency, such that the proximal ends of legs  220 B can be compressed inboard when desired, so that legs  220 B can have a combined diameter equal to or less than body  205 B of bridge post anchor  200 B. A slot  225 B is formed on distal end  210 B of body  205 B. In use, suture  130  is engaged in slot  225 B of body  205 B, and then bridge post anchor  200 B is driven distal end first into bridge hole BH, with legs  220 B first compressing inboard so as to enter the acetabulum and thereafter expanding outboard so as to secure bridge post anchor  200 B bridge hole BH. 
         [0095]    By way of further example but not limitation, and looking now at  FIGS. 24 and 25 , there is shown a bridge post anchor  300  which can be used to anchor suture  130  to the acetabulum. Bridge post anchor  300  generally comprises a body  305  having a distal end  310  and a proximal end  315 . A pair of legs  320  extend distally from distal end  310  of body  305 . Legs  320  are separated by a slot  325 . Legs  320  taper outwardly along their length, so that bridge post anchor  300  has a diameter at legs  320  which is somewhat larger than the diameter of body  305 . Legs  320  have a selected degree of resiliency, such that the distal ends of legs  320  can be compressed inboard when desired, so that legs  320  can have a combined diameter equal to or less than body  305  of bridge post anchor  300 . 
         [0096]    Bridge post anchor  300  also comprises a bore  330  which opens on distal end  310  of body  305 , intermediate legs  320 . Bore  330  extends proximally and intersects a threaded counterbore  335 . Bore  330  and counterbore  335  define an annular shoulder  340  at their intersection. 
         [0097]    Bridge post anchor  300  also comprises a suture spool  345  which is adapted to be movably received within threaded counterbore  335  of body  305 . More particularly, suture spool  345  comprises a distal hub  350 , a proximal hub  355 , and a neck  360  extending therebetween. A passageway  365  opens on the distal end of distal hub  350  and extends proximally so as to open on the outer surface of neck  360 . A screw thread  370  is formed on distal hub  350 . Screw thread  370  is sized to engage the threaded counterbore  335  in body  305 . A plurality of bores  375  extend through proximal hub  355 . A non-circular (e.g., hexagonal) opening  380  is formed in proximal hub  355 . Non-circular opening  380  receives a conventional rotary driver (e.g., a hex driver) D. Rotary driver D may be used to turn suture spool  345 , so as to move suture spool  345  within counterbore  335  and hence relative to body  305 . 
         [0098]    Prior to use, bridge post anchor  300  is configured so that suture spool  345  has its distal hub  350  screwed into counterbore  335  of body  305 , with proximal hub  355  extending out of body  305  (see  FIG. 26 ). 
         [0099]    Bridge post anchor  300  is preferably used as follows to re-attach the labrum to the acetabulum. 
         [0100]    After center post anchor  100  has been positioned in the acetabulum and a suture  130  has been passed through the labrum, the free end of suture  130  is passed outside the body and then it is threaded through bridge post anchor  300 , which also resides outside the body ( FIG. 27 ). More particularly, the free end of suture  130  is threaded through bridge post anchor  300  by passing the free end of the suture through slot  325  of body  305 , through bore  330  of body  305 , through passageway  365  of suture spool  345 , along the outside of neck  360  of suture spool  345 , and then through one of the plurality of bores  375  extending through proximal hub  355 , so that a free end of suture  130  extends from proximal hub  355  of suture spool  345 . It should be appreciated that as the free end of suture  130  extends through anchor body  305  and suture spool  345 , the free end of the suture  130  follows a tortuous path which provides some, but not complete, resistance to suture movement relative to anchor body  305  and suture spool  345 . 
         [0101]    Then, using driver D, suture spool  345  is advanced down body  305  of bridge post anchor  300  ( FIG. 28 ). 
         [0102]    Next, bridge post anchor  300  is advanced down the free end of suture  130  so that it enters the patient and is delivered to the surgical site. As this occurs, there is some resistance to distal motion of bridge post anchor  300  on the suture, due to the tortuous path followed by suture  130  through bridge post anchor  300 , however, this may be overcome by applying steady distal force to the bridge post anchor. 
         [0103]    Bridge post anchor  300  is brought adjacent to a bridge hole BH formed in acetabulum A. Then, with the free end of suture  130  being pulled slightly proximally so as to take up slack, legs  320  of bridge post anchor  300  are compressed and bridge post anchor  300  is pressed into bridge hole BH. Again, as this occurs, there is some resistance to distal motion of bridge post anchor  300  on the suture, due to the tortuous path followed by suture  130  through bridge post anchor  300 . Thereafter, the compression on legs  320  is released, whereupon legs  320  engage the side wall of bridge hole BH so as to secure bridge post anchor  300  to acetabulum A. 
         [0104]    Again, the distal ends of legs  320  are preferably beveled inwardly at their peripheries so that engagement of legs  320  with the rim of bridge hole BH during anchor insertion automatically causes legs  320  to compress inwardly to facilitate entry into bridge hole BH and thereafter automatically project outwardly so as to grip the surrounding bone. 
         [0105]    Then, with suture  130  held under substantial tension, driver D (engaged in non-circular hole  380 ) is used to retract suture spool  345  proximally within body  305  ( FIG. 29 ). As this occurs, the substantial tension on the free end of suture  130  causes the suture to bind on suture spool  345 , due to the tortuous path followed by suture  130  through the suture spool. As a result, proximal motion of suture spool  345  relative to body  305  (and hence proximal motion of suture spool  345  relative to acetabuum A, within which body  305  is fixed) has the effect of cinching the free end of suture  130 . Inasmuch as suture  130  is threaded through labrum L, this action has the effect of drawing the labrum to the acetabulum, so as to effect the desired labral re-attachment. 
         [0106]    Once cinching is complete, the procedure is then repeated using another bridge post anchor  300  to secure the remaining suture  130 . Then the free ends of the sutures extending out of bridge holes BH are cut away, and the sutures are removed from the surgical site. 
         [0107]    As discussed above, suture  130  is intended to be threaded through bridge post anchor  300  by passing the free end of the suture through slot  325  of body  305 , through bore  330  of body  305 , through passageway  365  of suture spool  345 , along the outside of neck  360  of suture spool  345 , and then through one of the plurality of bores  375  extending through proximal hub  355 , so that a free end of suture  130  extends from proximal hub  355  of suture spool  345 . This approach results in the free end of suture  130  following a tortuous path through the bridge post anchor. This tortuous path provides some, but not complete, resistance to suture movement relative to body  305  and suture spool  345 , such that longitudinal movement of suture spool  345  relative to body  305  can effect the aforementioned suture cinching. 
         [0108]    Alternatively, if desired, and looking now at  FIG. 29A , bores  375  in proximal hub  355  of suture spool  345  can be replaced with slots  376  having teeth  377  therein. Slots  376  and teeth  377  essentially form a suture cleat for securing the free end of suture  130  to suture spool  345 . More particularly, when the free end of suture  130  is to be secured to suture spool  345 , the free end of the suture is slipped into one of the slots  376 , where it is gripped by teeth  377 . As a result, subsequent movement of suture spool  345  within body  305  carries suture  130  with it, whereby to permit suture cinching as discussed above. 
         [0109]    Alternatively, or in addition to the foregoing, it is also possible to modify body  305  of bridge post anchor  300  so as to provide a cam-type cleat within body  305  of the anchor. More particularly, and looking now at  FIG. 29B , body  305  can be formed so that the walls  306  defining bore  330  are substantially resilient in the proximal direction but substantially rigid in the distal direction, and bore  330  can be formed with opposing teeth  307 . As a result of this construction, when the free end of suture  130  is advanced through bore  330  and is thereafter pulled proximally, walls  306  can yield proximally so as to permit suture  130  to pass thereby. However, since walls  306  are unable to yield in the distal direction, suture  130  is unable to return distally. Thus, walls  306  and teeth  307  effectively form a cam-type cleat within body  305  of the bridge post anchor, such that subsequent movement of suture spool  345  within body  305  carries suture  130  with it, whereby to permit suture cinching as discussed above. Of course, with this design, it is important that suture spool  345  sit sufficiently proximally of walls  306  to permit walls  306  to yield proximally as just discussed. 
         [0110]    Alternatively, and looking now at  FIG. 30 , a bridge post anchor  300 A can be provided which is generally similar to bridge post anchor  300  described above, but which utilizes a suture spool  345 A which permits the suture to be wound around neck  360 A of suture spool  345 A. More particularly, in this form of the invention, suture spool  345 A is constructed so that its proximal hub  355 A can rotate about distal hub  350 A and neck  360 A so as to wrap suture  130  around the neck, thereby increasing stability of suture position upon completion of the labrum attachment. In this form of the invention, distal hub  350 A and neck  360 A may comprise a non-circular opening  380 A′ for turning the distal hub and neck as a unit, and proximal hub  355 A may comprise a non-circular opening  380 A″ for turning proximal hub  355 A. Driver D may comprise coaxial elements D′ and D″, with element D′ turning distal hub  350 A and neck  360 A as a unit, and with element D″ turning proximal hub  355 A. 
         [0111]    If desired, the aforementioned suture cleats in proximal hub  355  of suture spool  345  ( FIG. 29A ) and/or the cam-type cleat within body  305  of the bridge post anchor ( FIG. 29B ) can be combined with the construction where proximal hub  355  is turned separately from distal hub  350  and neck  360  ( FIG. 30 ). 
         [0112]    Furthermore, still other constructions will be apparent to those skilled in the art whereby suture spool  345  may be turned independently of body  305  so as to cinch the suture holding labrum L. 
       Trans-Labral Anchor Fixation 
       [0113]    In the foregoing description, the bodies of center post anchor  100  and distal post anchors  200 ,  300  are described as being deployed directly into acetabulum A, without first passing through labrum L. However, it should be appreciated that, if desired, the bodies of center post anchor  100  and/or distal post anchors  200 ,  300  may be deployed in acetabulum A trans-labrally, i.e., by passing through the labrum before entering the acetabulum. This approach can eliminate the additional step of passing the suture through the labrum after the center post anchor has been set, and can obviate the need for an independent suture passing device (e.g., needle  135  or an independent suture passer instrument such as disclosed above). 
       Use of the Novel Method and Apparatus for Other Joints, Etc. 
       [0114]    It should be appreciated that the novel method and apparatus of the present invention may be used for attaching other tissues and the like to the acetabulum, and/or may be used for attaching other tissues and the like to other bones. By way of example but not limitation, the novel method and apparatus of the present invention may be used to attach soft tissue and prostheses in the knee joint, in the shoulder joint, etc. 
       Modifications of the Preferred Embodiments 
       [0115]    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.