Abstract:
Apparatus for securing a first object to a second object, the apparatus comprising: an elongated body having a distal end, a proximal end, and a lumen extending between the distal end and the proximal end, the lumen comprising a first section and a second section, the first section of the lumen being disposed distal to the second section of the lumen, and with the first section of the lumen having a wider diameter than the second section of the lumen; at least one longitudinally-extending slit extending through the side wall of the elongated body and communicating with the lumen, the at least one longitudinally-extending slit having a distal end and a proximal end, with the distal end of the at least one longitudinally-extending slit being spaced from the distal end of the elongated body; and an elongated element extending through the lumen of the elongated body.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATIONS 
       [0001]    This patent application: 
         [0002]    (i) is a continuation-in-part of pending prior U.S. patent application Ser. No. 12/839,246, filed Jul. 19, 2010 by Chris Pamichev et al. for METHOD AND APPARATUS FOR RE-ATTACHING THE LABRUM TO THE ACETABULUM, INCLUDING THE PROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM (Attorney&#39;s Docket No. FIAN-4655), which in turn claims benefit of (1) prior U.S. Provisional Patent Application Ser. No. 61/271,205, filed Jul. 17, 2009 by Chris Pamichev et al. for METHOD AND APPARATUS FOR RE-SECURING THE LABRUM TO THE ACETABULUM, INCLUDING THE PROVISION AND USE OF A NOVEL NANO TACK SYSTEM (Attorney&#39;s Docket No. FIAN-46 PROV), and (2) pending prior U.S. Provisional Patent Application Ser. No. 61/326,709, filed Apr. 22, 2010 by Chris Pamichev et al. for METHOD AND APPARATUS FOR RE-SECURING THE LABRUM TO THE ACETABULUM, INCLUDING THE PROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM (Attorney&#39;s Docket No. FIAN-55 PROV); and (ii) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 61/326,709, filed Apr. 22, 2010 by Chris Pamichev et al. for METHOD AND APPARATUS FOR RE-SECURING THE LABRUM TO THE ACETABULUM, INCLUDING THE PROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM (Attorney&#39;s Docket No. FIAN-55 PROV). 
         [0003]    The three (3) above-identified patent applications are hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0004]    This invention relates to surgical methods and apparatus in general, and more particularly to surgical methods and apparatus for treating a hip joint. 
       BACKGROUND OF THE INVENTION 
       [0005]    The Hip Joint In General 
         [0006]    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. 
         [0007]    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. 
         [0008]    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. 
         [0009]    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. 
         [0010]    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 
       [0011]    The hip joint is formed at the junction of the leg and the torso. More particularly, and looking now at  FIG. 2 , the head 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. 
         [0012]    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. 
         [0013]    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 by the age of  25  or so) in order to collectively form the acetabular cup. The acetabular cup receives the head of the femur. 
         [0014]    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 . 
         [0015]    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  FIGS. 8 and 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, for example,  FIGS. 11 and 12 , which show the iliofemoral ligament, with  FIG. 11  being an anterior view and  FIG. 12  being a posterior view. 
       Pathologies of the Hip Joint 
       [0016]    As noted above, the hip joint is susceptible to a number of different pathologies. These pathologies can have both congenital and injury-related origins. 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 cam-type femoroacetabular impingement (i.e., 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 pincer-type femoroacetabular impingement (i.e., pincer-type FAI). Impingement can result in a reduced range of motion, substantial pain and, in some cases, significant deterioration of the hip joint. 
         [0017]    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 out 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. 
         [0018]    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 
       [0019]    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. 
         [0020]    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 large incisions into the interior 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. 
         [0021]    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. 
         [0022]    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 
       [0023]    Unfortunately, minimally-invasive treatments for pathologies of the hip joint have lagged far behind minimally-invasive treatments for pathologies of the shoulder joint and the 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. 
         [0024]    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. 
         [0025]    Furthermore, the pathways for entering the interior of the hip joint (i.e., the natural pathways which exist between adjacent bones and/or delicate neurovascular structures) 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. 
         [0026]    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 offset from the angle at which the instrument addresses the tissue. This makes drilling into bone, for example, significantly more complicated than where the angle of approach is effectively aligned with the angle at which the instrument addresses the tissue, 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 at which the instrument addresses the tissue. 
         [0027]    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. 
         [0028]    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 
       [0029]    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. 
         [0030]    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 which has its base securely attached to the acetabulum, and  FIG. 17 , which shows a portion of the labrum (in this case the tip) detached from the acetabulum. 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. 
         [0031]    Unfortunately, current methods and apparatus for arthroscopically repairing (e.g., re-attaching) the labrum are somewhat problematic. The present invention is intended to improve upon the current approaches for labrum repair. 
         [0032]    More particularly, current approaches for arthroscopically repairing 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. See  FIG. 18 . 
         [0033]    Unfortunately, bone anchors of the sort described above are traditionally used for re-attaching ligaments to bone and, as a result, tend to be relatively large, since they must carry the substantial pull-out forces normally associated with ligament reconstruction. However, this large anchor size is generally unnecessary for labrum re-attachment, since the labrum is not subjected to substantial pull-out forces, and the large anchor size typically causes unnecessary trauma to the patient. 
         [0034]    Furthermore, the large size of traditional bone anchors can be problematic when the anchors are used for labrum re-attachment, since the bone anchors generally require a substantial bone mass for secure anchoring, and such a large bone mass is generally available only a substantial distance up the acetabular shelf. In addition, the large size of the bone anchors generally makes it necessary to set the bone anchor a substantial distance up the acetabular shelf, in order to ensure that the distal tip of the bone anchor does not inadvertently break through the acetabular shelf and contact the articulating surfaces of the joint. However, labral re-attachment utilizing a bone anchor set high up into the acetabular shelf creates a suture path, and hence a labral draw force, which is not directly aligned with the portion of the acetabular rim where the labrum is to be re-attached. As a result, an “indirect” draw force (also known as eversion) is typically applied to the labrum, i.e., the labrum is drawn around the rim of the acetabulum rather than directly into the acetabulum. See  FIG. 18 . This can sometimes result in a problematic labral re-attachment and, ultimately, can lead to a loss of the suction seal between the labrum and femoral head, which is a desired outcome of the labral re-attachment procedure. 
         [0035]    Alternatively, the suture path can also surround the labrum, thus placing a suture on both sides of the labrum, including the articular side of the labrum, and thus exposing the articular surface of the femur to a foreign body, which could in turn cause damage to the articular surface (i.e., the articular cartilage) of the femur. 
         [0036]    Accordingly, a new approach is needed for arthroscopically re-attaching the labrum to the acetabulum. 
       SUMMARY OF THE INVENTION 
       [0037]    The present invention provides a novel method and apparatus for re-attaching the labrum to the acetabulum. Among other things, the present invention comprises the provision and use of a novel suture anchor system. 
         [0038]    In one form of the invention, there is provided apparatus for securing a first object to a second object, the apparatus comprising: 
         [0039]    an elongated body having a distal end, a proximal end, and a lumen extending between the distal end and the proximal end, the lumen comprising a first section and a second section, the first section of the lumen being disposed distal to the second section of the lumen, and with the first section of the lumen having a wider diameter than the second section of the lumen; 
         [0040]    at least one longitudinally-extending slit extending through the side wall of the elongated body and communicating with the lumen, the at least one longitudinally-extending slit having a distal end and a proximal end, with the distal end of the at least one longitudinally-extending slit being spaced from the distal end of the elongated body; and 
         [0041]    an elongated element extending through the lumen of the elongated body, the elongated element comprising a proximal end and a distal end and having an enlargement at its distal end, the enlargement having a diameter greater than the second section of the lumen. 
         [0042]    In another form of the invention, there is provided apparatus for securing a first object to a second object, the apparatus comprising: 
         [0043]    an elongated body having a distal end, a proximal end, and a lumen extending between the distal end and the proximal end, the lumen comprising a first section and a second section, the first section of the lumen being disposed distal to the second section of the lumen, and with the first section of the lumen having a wider diameter than the second section of the lumen; and 
         [0044]    a suture extending through the lumen of the elongated body, the suture comprising a proximal end and a distal end and having a suture knot at its distal end, the suture knot having a diameter greater than the second section of the lumen. 
         [0045]    In another form of the invention, there is provided apparatus for securing a first object to a second object, the apparatus comprising: 
         [0046]    an elongated body having a distal end, a proximal end, and a lumen extending between the distal end and the proximal end, the lumen comprising a first section and a second section, the first section of the lumen being disposed distal to the second section of the lumen and with the first section of the lumen having a wider diameter than the second section of the lumen; 
         [0047]    the side wall of the elongated body having a weakened section therein adjacent to the second section of the lumen; and 
         [0048]    an elongated element extending through the lumen of the elongated body, the elongated element comprising a proximal end and a distal end and having an enlargement at its distal end, the enlargement having a diameter greater than the second section of the lumen. 
         [0049]    In another form of the invention, there is provided a method for securing a first object to a second object, the method comprising: 
         [0050]    providing apparatus comprising:
       an elongated body having a distal end, a proximal end, and a lumen extending between the distal end and the proximal end, the lumen comprising a first section and a second section, the first section of the lumen being disposed distal to the second section of the lumen, and with the first section of the lumen having a wider diameter than the second section of the lumen;   at least one longitudinally-extending slit extending through the side wall of the elongated body and communicating with the lumen, the at least one longitudinally-extending slit having a distal end and a proximal end, with the distal end of the at least one longitudinally-extending slit being spaced from the distal end of the elongated body; and   an elongated element extending through the lumen of the elongated body, the elongated element comprising a proximal end and a distal end and having an enlargement at its distal end, the enlargement having a diameter greater than the second section of the lumen;       
 
         [0054]    inserting the elongated body into the second object; 
         [0055]    moving the enlargement proximally so as to expand the elongated body; and 
         [0056]    securing the first object to the second object with the elongated element. 
         [0057]    In another form of the invention, there is provided a method for securing a first object to a second object, the method comprising: 
         [0058]    providing apparatus comprising:
       an elongated body having a distal end, a proximal end, and a lumen extending between the distal end and the proximal end, the lumen comprising a first section and a second section, the first section of the lumen being disposed distal to the second section of the lumen, and with the first section of the lumen having a wider diameter than the second section of the lumen; and   a suture extending through the lumen of the elongated body, the suture comprising a proximal end and a distal end and having a suture knot at its distal end, the suture knot having a diameter greater than the second section of the lumen;       
 
         [0061]    inserting the elongated body into the second object; 
         [0062]    moving the suture knot proximally so as to expand the elongated body; and 
         [0063]    securing the first object to the second object with the suture. 
         [0064]    In another form of the invention, there is provided a method for securing a first object to a second object, the method comprising: 
         [0065]    providing apparatus comprising:
       an elongated body having a distal end, a proximal end, and a lumen extending between the distal end and the proximal end, the lumen comprising a first section and a second section, the first section of the lumen being disposed distal to the second section of the lumen, and with the first section of the lumen having a wider diameter than the second section of the lumen;   the side wall of the elongated body having a weakened section therein adjacent to the second section of the lumen; and   an elongated element extending through the lumen of the elongated body, the elongated element comprising a proximal end and a distal end and having an enlargement at its distal end, the enlargement having a diameter greater than the second section of the lumen;       
 
         [0069]    inserting the elongated body into the second object; 
         [0070]    moving the enlargement proximally so as to expand the elongated body; and 
         [0071]    securing the first object to the second object with the elongated element. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0072]    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: 
           [0073]      FIGS. 1A-1D  are schematic views showing various aspects of hip motion; 
           [0074]      FIG. 2  is a schematic view showing bone structures in the region of the hip joint; 
           [0075]      FIG. 3  is a schematic anterior view of the femur; 
           [0076]      FIG. 4  is a schematic posterior view of the top end of the femur; 
           [0077]      FIG. 5  is a schematic view of the pelvis; 
           [0078]      FIGS. 6-12  are schematic views showing bone and soft tissue structures in the region of the hip joint; 
           [0079]      FIG. 13  is a schematic view showing cam-type femoroacetabular impingement (i.e., cam-type FAI); 
           [0080]      FIG. 14  is a schematic view showing pincer-type femoroacetabular impingement (i.e., pincer-type FAI); 
           [0081]      FIG. 15  is a schematic view showing a labral tear; 
           [0082]      FIG. 16  is a schematic view showing a normal labrum which has its base securely attached to the acetabulum; 
           [0083]      FIG. 17  is a schematic view showing a portion of the labrum detached from the acetabulum; 
           [0084]      FIG. 18  is a schematic view showing a bone anchor being used to re-attach the labrum to the acetabulum; 
           [0085]      FIGS. 19-27  are schematic views showing a novel suture anchor system for use in arthroscopically re-attaching a detached labrum to the acetabulum; 
           [0086]      FIGS. 28 and 28A  are schematic views showing the suture anchor system of  FIGS. 19-27  being used to re-attach the labrum to the acetabulum; 
           [0087]      FIGS. 29-31  are schematic views showing an alternative form of the suture anchor system of the present invention; 
           [0088]      FIG. 32  is a schematic view showing another alternative form of the suture anchor system of the present invention; 
           [0089]      FIGS. 33-38  are schematic views showing alternative arrangements for coupling the anchor of the suture anchor system of  FIGS. 19-27  to the inserter of the suture anchor system of  FIGS. 19-27 ; 
           [0090]      FIGS. 39-41  are schematic views showing still another alternative form of the suture anchor system of the present invention; 
           [0091]      FIG. 42  is a schematic view showing yet another alternative form of the suture anchor system of the present invention; 
           [0092]      FIGS. 43-45  are schematic views showing another alternative form of the suture anchor system of the present invention; 
           [0093]      FIGS. 46-48  are schematic views showing still another alternative form of the suture anchor system of the present invention; 
           [0094]      FIGS. 49-50  are schematic views showing yet another alternative form of the suture anchor system of the present invention; 
           [0095]      FIG. 51  is a schematic view showing another alternative form of the suture anchor system of the present invention; and 
           [0096]      FIGS. 52-54  are schematic views showing still another alternative form of the suture anchor system of the present invention; and 
           [0097]      FIGS. 55-60  are schematic views showing yet another alternative form of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The Novel Suture Anchor System of the Present Invention in General 
       [0098]    The present invention provides a novel method and apparatus for arthroscopically re-attaching the labrum to the acetabulum. Among other things, the present invention comprises the provision and use of a novel suture anchor system. 
         [0099]    More particularly, and looking now at  FIG. 19 , there is shown a novel suture anchor system  5  for use in arthroscopically re-attaching a detached labrum to the acetabulum. Suture anchor system  5  generally comprises an anchor  10 , a suture  15  secured to anchor  10 , and an inserter  20  for delivering anchor  10  into the acetabulum, whereby suture  15  may be used to secure a detached labrum to the acetabular rim as will hereinafter be discussed in further detail. Suture anchor system  5  preferably also comprises a hollow guide  25  for delivering components from outside of the body to the acetabulum, and a punch (or drill)  30  which may be used to prepare a seat for anchor  10  in the acetabulum. 
         [0100]    Looking next at  FIGS. 19-23 , anchor  10  comprises a generally cylindrical body  35  having a distal end  40 , a proximal end  45 , and a lumen  50  extending between distal end  40  and proximal end  45 . In one preferred form of the present invention, lumen  50  comprises a distal end reservoir  55 , a short intermediate portion  60 , and an elongated proximal portion  65 . As seen in  FIG. 23 , distal end reservoir  55  has a diameter which is greater than the diameter of short intermediate portion  60 , and short intermediate portion  60  has a diameter which is greater than the diameter of elongated proximal portion  65 . And in one preferred form of the present invention, the outer surface of generally cylindrical body  35  comprises a plurality of ribs  70  spaced along the length of generally cylindrical body  35 , so as to enhance the “holding power” of anchor  10  in bone. In one particularly preferred form of the present invention, ribs  70  sub-divide the length of generally cylindrical body  35  into a plurality of segments, with each segment having a generally frusto-conical configuration ( FIGS. 21 and 22 ). 
         [0101]    Near (but spaced from) the distal end  40  of generally cylindrical body  35 , there is provided a longitudinally-extending slit  75  which extends completely through one side wall (but not the other) of generally cylindrical body  35 . Thus, longitudinally-extending slit  75  communicates with lumen  50  of anchor  10 . The distal end of longitudinally-extending slit  75  terminates in a distal relief hole  80 , and the proximal end of longitudinally-extending slit  75  terminates in a proximal relief hole  85 . It will be appreciated that distal relief hole  80  is spaced from distal end  40  of generally cylindrical body  35 , so that a solid distal ring  90  is located at the distal end of generally cylindrical body  35 , whereby to provide the distal end of generally cylindrical body  35  with a degree of structural integrity. 
         [0102]    Looking now at FIGS.  20  and  24 - 26 , suture  15  generally comprises a distal loop  95  terminating in an enlargement  100  at its distal end and connected to a proximal open loop  105  at its proximal end. More particularly, distal loop  95  extends through short intermediate portion  60  and elongated proximal portion  65  of lumen  50 . Enlargement  100  may comprise a solid member (e.g., cylindrical, conical, etc.) attached to the distal end of distal loop  95 , or it may comprise a suture knot formed by knotting off the distal ends of distal loop  95  of suture  15 , etc. Where enlargement  100  comprises a suture knot, this suture knot may or may not be hardened, shaped or stabilized with cement, heat, etc. For purposes of illustration, enlargement  100  is shown in the drawings schematically, i.e., as a generally cylindrical structure, but it should be appreciated that this is being done solely for clarity of illustration, and enlargement  100  may assume any other shapes and/or configurations (including that of a suture knot) consistent with the present invention. Enlargement  100  is sized so that it is small enough to be seated in distal end reservoir  55  of generally cylindrical body  35  (see, for example,  FIGS. 24 and 25 ), but large enough so that it may not enter short intermediate portion  60  of generally cylindrical body  35  without causing radial expansion of generally cylindrical body  35  (see, for example,  FIG. 26 ). Proximal open loop  105  extends back through the interior of inserter  20  ( FIGS. 19 and 20 ) and provides a pair of free suture ends emanating from the proximal end of inserter  20  ( FIG. 19 ), as will hereinafter be discussed. 
         [0103]    Looking now at  FIGS. 19 and 20 , inserter  20  generally comprises a hollow push tube  110  having a lumen  115  extending therethrough. Inserter  20  terminates at its distal end in a drive surface  120  for engaging the proximal end  45  of anchor  10 , and terminates at its proximal end in a handle  125 . Handle  125  may include features to secure the free ends of suture  15 , e.g., one or more suture cleats, suture slots, suture clamps, etc. Where such features are provided, and where appropriate, handle  125  may also include one or more release mechanisms to release the free ends of suture  15 . Handle  125  may also have one or more mechanisms to apply tension to the secured free ends of suture  15 . Suture  15  (i.e., proximal open loop  105  of suture  15 ) extends through lumen  115  of hollow push tube  110 . By maintaining a slight proximally-directed tension on the proximal end of suture  15  (e.g., by maintaining a slight proximally-directed tension on the free suture ends of proximal open loop  105 ), anchor  10  can be held against the drive surface  120  of hollow push tube  110 , thereby providing a degree of control for maneuvering the anchor. 
         [0104]    Preferably anchor  10 , suture  15  and inserter  20  are pre-assembled into a single unit, with suture  15  extending back through lumen  115  of inserter  20  with a slight proximal tension so as to hold anchor  10  on the distal end of inserter  20 . 
         [0105]    Suture anchor system  5  preferably also comprises a hollow guide  25  for guiding components from outside of the body to the acetabulum. More particularly, hollow guide  25  generally comprises a lumen  130  for slidably receiving anchor  10  and inserter  20  therein, as will hereinafter be discussed. The internal diameter of hollow guide  25  is preferably approximately equal to the largest external feature of anchor  10  (e.g., one or more of the barbs  70 ), so that anchor  10  can make a close sliding fit within the interior of hollow guide  25 . Alternatively, the internal diameter of hollow guide  25  may be slightly smaller or larger than the largest external feature of anchor  10  if desired. Where suture anchor system  5  also comprises a punch (or drill)  30 , lumen  130  of hollow guide  25  is preferably sized to slidably receive punch (or drill)  30 , as will hereinafter be discussed. The distal end of hollow guide  25  preferably includes a sharp tip/edge for penetrating the labrum and engaging the acetabulum, as will hereinafter be discussed. 
         [0106]    If desired, and looking now at  FIGS. 19 and 27 , suture anchor system  5  may also comprise a punch (or drill)  30  having a sharp distal end  135  and a proximal end  140  having a handle  145  mounted thereto. Where element  30  is a drill, handle  145  could comprise a mount for the drill so as to facilitate turning the drill with a powered driver, etc. Again, the sharp distal end  135  of punch (or drill)  30  is adapted to penetrate the acetabulum, as will hereinafter be discussed. 
       Method for Arthroscopically Re-Attaching the Labrum to the Acetabulum Using the Novel Suture Anchor System of the Present Invention 
       [0107]    Suture Anchor system  5  is preferably used as follows to secure a detached labrum to the acetabulum. 
         [0108]    First, the sharp distal end  136  of hollow guide  25  is passed through the labrum and positioned against the acetabulum at the location where anchor  10  is to be deployed. Preferably the sharp distal end of hollow guide  25  penetrates through the labrum and a short distance into the acetabulum so as to stabilize the hollow guide vis-à-vis the acetabulum. A stylet (e.g., an obturator) may be used to fill the hollow guide  25  during such insertion and thus prevent tissue coring of the labrum during insertion. The distal portion of the punch (or drill)  30  may also be used to fill the hollow tip of the hollow guide  25  during such insertion. 
         [0109]    Next, if desired, punch (or drill)  30  may be used to prepare a seat in the acetabulum to receive anchor  10 . More particularly, if punch (or drill)  30  is used, the sharp distal end  135  of punch (or drill)  30  is passed through hollow guide  25  (thereby also passing through the labrum) and advanced into the acetabulum so as to form an opening (i.e., a seat) in the bone to receive anchor  10 . Then, while hollow guide  25  remains stationary, punch (or drill)  30  is removed from hollow guide  25 . 
         [0110]    Next, inserter  20 , carrying anchor  10  thereon, is passed through hollow guide  25  (thereby also passing through the labrum) and into the seat formed in the acetabulum. As anchor  10  is advanced into the bone, the body of anchor  10  (e.g., ribs  70 ) makes an interference fit with the surrounding bone, whereby to initially bind the anchor to the bone. At the same time, the solid distal ring  90  located at the distal end of the anchor provides the structural integrity needed to keep the anchor intact while it penetrates into the bone. When anchor  10  has been advanced an appropriate distance into the acetabulum, the proximal end of suture  15  (i.e., proximal open loop  105 ) is pulled proximally while the distal end of inserter  20  is held in position, thereby causing enlargement  100  to move proximally relative to the generally cylindrical body  35 , forcing the distal end of generally cylindrical body  35  to split and expand, in the manner shown in  FIG. 26 , whereby to further bind anchor  10 , and hence suture  15 , to the bone. In one preferred form of the present invention, expansion of generally cylindrical body  35  occurs along some or all of the circumference of the generally cylindrical body, and there may be variations in the amount of expansion about the circumference of the generally cylindrical body, e.g., with the construction shown in  FIG. 26 , there may be greater expansion in a direction perpendicular to the direction of longitudinally-extending slits  75  (for example, in the direction of the arrows shown in  FIG. 26 ). It will be appreciated that the location and magnitude of expansion of generally cylindrical body  35  can be controlled by the number and location of longitudinally-extending slits  75 , the configuration of enlargement  100 , the configuration of generally cylindrical body  35  (e.g., its lumen  50  and the associated side wall of the cylindrical body  35  adjacent the lumen), etc. In one preferred form of the present invention, expansion of generally cylindrical body  35  occurs at the zone where distal end reservoir  55  meets short intermediate portion  60 , with expansion occurring as enlargement  100  moves out of the comparatively larger diameter distal end reservoir  55  and into the comparatively smaller diameter intermediate portion  60 . 
         [0111]    Significantly, in view of the modest holding power required to secure the labrum in place, anchor  10  can have a very small size, much smaller than a typical bone anchor of the sort used to hold a ligament in place. By way of example but not limitation, anchor  10  may have a length of 0.325 inches, an outer diameter (unexpanded) of 0.063 inches, and an outer diameter (expanded) of 0.080 inches. This small size enables a minimal puncture to be made in the labrum (and hence a minimal hole to be made in the labrum), thus reducing potential damage to the labral tissue and enabling a more accurate puncture location through the labrum. The small size of anchor  10  also allows the anchor to be placed closer to, or directly into, the rim of the acetabular cup, without fear of the anchor penetrating into the articulating surfaces of the joint. See, for example,  FIG. 28 , which shows anchor  10  placed close to the rim of the acetabular cup, and  FIG. 28A , which shows anchor  10  placed directly into the rim of the acetabular cup. This significantly reduces, or entirely eliminates, the labrum eversion problems discussed above. Furthermore, the small size of the anchor significantly reduces trauma to the tissue of the patient. 
         [0112]    Once anchor  10  has been set in the acetabulum, guide  25  is removed from the surgical site, leaving anchor  10  deployed in the acetabulum and suture  15  extending out through the labrum. 
         [0113]    This process may then be repeated as desired so as to deploy additional anchors through the labrum and into the acetabulum, with each anchor having a pair of associated free suture ends extending out through the labrum. 
         [0114]    Finally, the labrum may be secured to the acetabular cup by tying the labrum down to the acetabulum using the free suture ends emanating from the one or more anchors. 
       Some Alternative Constructions for the Novel Suture Anchor System of the Present Invention 
       [0115]    If desired, and looking now at  FIGS. 29-31 , a deployment cylinder  150  may be disposed on distal loop  95  of suture  15  just proximal to enlargement  100 . Deployment cylinder  150  can be advantageous where enlargement  100  comprises a suture knot, since the deployment cylinder can ensure the uniform application of a radial expansion force to the wall of the anchor body even where the suture knot has a non-uniform configuration. Deployment cylinder  150  may have a beveled proximal end  155  to facilitate expansion of anchor  10  when suture  15  is pulled proximally.  FIG. 29  depicts anchor  10  in an unexpanded state, while  FIGS. 30-31  depict the anchor  10  in an expanded state. 
         [0116]    Furthermore, one or more of the ribs  70  may utilize a different construction than that shown in  FIGS. 21-23 . More particularly, in  FIGS. 21-23 , each of the ribs  70  comprises a proximal portion which comprises a cylindrical surface  160 . Such a cylindrical surface provides increased surface area contact for engaging the adjacent bone when anchor  10  is disposed in the acetabulum. However, if desired, one or more of the ribs  70  may terminate in a sharp proximal rim  165  ( FIGS. 29-31 ) for biting into adjacent bone when suture  15  is pulled proximally. 
         [0117]    Or one or more of the ribs  70  may be slotted as shown in  FIG. 32  so as to provide a rib with increased flexibility. Such a construction can be useful since it allows the slotted rib  70  to be radially compressed so as to fit within inserter  20  and then radially expanded, in a spring-like manner, when deployed in the acetabulum. 
         [0118]    If desired, alternative arrangements can be provided for coupling anchor  10  to the distal end of inserter  20 . More particularly, in  FIGS. 33 and 34 , a male-female connection is used to couple anchor  10  to inserter  20 , with anchor  10  having a male projection  170  and inserter  20  having a corresponding female recess  175 . In  FIGS. 35 and 36 , inserter  20  includes the male projection  170  and anchor  10  has the corresponding female recess  175 . In  FIGS. 37 and 38 , inserter  20  has a convex surface  180  and anchor  10  has a corresponding concave surface  185 . Still other constructions of this type will be apparent to those skilled in the art in view of the present disclosure. 
         [0119]    Looking next at  FIGS. 39-41 , in another form of present invention, suture  15  is intended to exit anchor  10  at proximal relief hole  85  and extend along the exterior of the generally cylindrical body  35 . If desired, slots  190  may be provided in ribs  70  so as to accommodate suture  15  therein. 
         [0120]    In another form of the present invention, and looking now at  FIG. 42 , suture  15  can be replaced by a solid shaft  195 . More particularly, solid shaft  195  extends through lumen  50  of anchor  10  and lumen  115  of inserter  20 , and has enlargement  100  formed on its distal end. Proximal movement of solid shaft  195  causes enlargement  100  to expand the distal end of anchor  10  so as to cause anchor  10  to grip adjacent bone. 
         [0121]    If desired, one or both of distal relief hole  80  and proximal relief hole  85  may be omitted, with longitudinally-extending slit  75  terminating in a blind surface at one or both ends. 
         [0122]    Furthermore, if desired more than one longitudinally-extending slit  75  may be provided in anchor  10 , e.g., two diametrically-opposed longitudinally-extending slits  75  may be provided. Additionally, if desired, longitudinally-extending slit  75  may extend all the way to the distal end of the anchor body, rather than stopping short of the distal end of the anchor body. See, for example,  FIGS. 43 and 44 , which show two diametrically-opposed, longitudinally-extending slits  75 , wherein the slits extend all the way to the distal end of anchor  10 , and with the two figures showing examplary rib configurations. See also  FIG. 45 , which shows an anchor  10  having a single longitudinally-extending slit  75 , wherein the slit extends all the way to the distal end of the anchor. 
         [0123]    If desired, and looking now at  FIGS. 46-48 , lumen  50  may extend along a longitudinal axis  200  which is eccentric to the longitudinal axis  205  of generally cylindrical body  35 . Such an eccentric construction can provide a thinner side wall on one side of the anchor and a thicker side wall on another side of the anchor, so as to create preferential body expansion. 
         [0124]    Or anchor  10  may be provided with an angled through-hole to create varying wall thicknesses and non-symmetric effects as shown in  FIGS. 49 and 50 . 
         [0125]    If desired, and looking now at  FIG. 51 , anchor  10  can be constructed so that longitudinally-extending slit  75  is omitted entirely. In this form of the invention, anchor  10  is preferably formed with one or more thin-walled sections  210  ( FIGS. 52-54 ) which fracture when enlargement  100  is forced proximally. 
         [0126]    Alternatively, in another form of the invention, anchor  10  is constructed so that its generally cylindrical body  35  expands radially when enlargement  100  moves proximally, but the distal end of the anchor does not split open. See  FIGS. 55-58 . Again, the direction and extent of the expansion of cylindrical body  35  may be controlled by the number and location of the longitudinally-extending slits  75 , the configuration of enlargement  100 , the configuration of generally cylindrical body  35  (e.g., its lumen  50  and the associated side wall of the cylindrical body  35  adjacent the lumen), etc. 
       Additional Construction Details 
       [0127]    Anchor  10  can be made out of any material consistent with the present invention, e.g., anchor  10  can be made out of a biocompatible plastic (such as PEEK), an absorbable polymer (such as poly-L-lactic acid, PLLA), bio-active materials such as hydrogels, or metal (such as stainless steel or titanium). 
         [0128]    Suture  15  can be made out of any material consistent with the present invention, e.g., common surgical suture materials. One such material is woven polymer such as PE or UHMWPE. Another material is a co-polymer material such as UHMWPE/polyester. Yet another material is an absorbable polymer such as polyglycolic acid, polylactic acid, polydioxanone, or caprolactone. Proximal loop  105  is preferably a #1 suture size; alternatively, it is a #2 suture size, a #0 suture size, or a #2-0 suture size. Distal loop  95  is preferably a #2-0 suture size; alternatively, it is a #2 suture size, a #1 suture size, or a #0 suture size. 
         [0129]    As noted above, enlargement  100  may comprise a solid member attached to the distal end of distal loop  95 , or it may comprise a suture knot formed by knotting off the distal ends of distal loop  95  of suture  15 . In this latter construction, enlargement  100  can be formed out of a single knot or multiple knots. It can be an overhand knot or other knot such as a “FIG.  8 ” knot. Suture  15  can also be heat formed so as to create the enlargement  100 . This will create a more rigid feature that better enables movement of enlargement  100  from its distal position to its more proximal position. Such heat forming could also be done on a knot or to seal the suture ends distal to the knot. 
         [0130]    Alternative Construction And Method Of Use In one form of the present invention, anchor  10  of suture anchor system  5  may be delivered trans-labrally, i.e., through the labrum and into the acetabular bone, e.g., such as was described above. 
         [0131]    In an alternative embodiment of the present invention, anchor  10  may be placed directly into the acetabular bone, without passing through the labrum first, and then suture  15  may be passed through the labrum. In this form of the invention, the components of suture anchor system  5  may remain the same. Alternatively, in this form of the invention, the distal end of hollow guide  25  need not have a sharp tip/edge  136  for penetrating the labrum as described above, and may instead have engagement features for engaging the acetabular bone. One such feature may be a tooth or a plurality of teeth. In this form of the invention, the distal end of the hollow guide may also include a window for confirming that the anchor is properly placed into the bone. 
       Curved or Angled Configuration and Method of Use 
       [0132]    Suture anchor system  5  may also comprise a curved or angled configuration. More particularly, hollow guide  25  may comprise a curve or angle at its distal end. In this form of the invention, the punch (or drill)  30 , inserter  20  and anchor  10  are adapted to pass through the curved or angled hollow guide  25  so as to permit a curved or angled delivery of anchor  10 . 
       Use of the Novel Suture Anchor System for Other Tissue Re-Attachment 
       [0133]    It should be appreciated that suture anchor system  5  may also be used for re-attaching other soft tissue of the hip joint, or for re-attaching tissue of other joints, or for re-attaching tissue elsewhere in the body. In this respect it should be appreciated that suture anchor system  5  may be used to attach soft tissue to bone or soft tissue to other soft tissue, or for attaching objects (e.g., prostheses) to bone other tissue. 
       Modifications of the Preferred Embodiments 
       [0134]    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.