Abstract:
This disclosure relates to arthroscopic resurfacing techniques for treating diseased bone. The techniques include passing a graft into a joint and fixating the graft against an articulating surface of a bone of the joint. A method for resurfacing a bone according to an exemplary aspect of the present disclosure includes, among other things, sizing a graft based on a replicate of a bone, arthroscopically positioning the graft against an articulating surface of the bone, and securing the graft to the bone using at least one suture anchor.

Description:
BACKGROUND 
       [0001]    This disclosure relates to surgical methods for resurfacing bone to treat arthritic portions of bone. 
         [0002]    Repetitive trauma to a joint, such as an ankle, knee, hip or shoulder joint, may damage bone, particularly at the articulating surfaces of the joint. If not treated, the damaged bone could lead to relatively significant arthritic pain and loss of motion. Over time, arthritis can cause the loss of articular cartilage. For some individuals, joint replacement surgery may be an undesirable option for alleviating severe arthritis pain and any associated loss of articular cartilage. 
       SUMMARY 
       [0003]    This disclosure relates to arthroscopic resurfacing techniques for treating diseased bone. The techniques include passing a graft into a joint and fixating the graft against an articulating surface of a bone of the joint. 
         [0004]    A method for resurfacing a bone according to an exemplary aspect of the present disclosure includes, among other things, sizing a graft based on a replicate of a bone, arthroscopically positioning the graft against an articulating surface of the bone, and securing the graft to the bone using at least one suture anchor. 
         [0005]    In a further non-limiting embodiment of the foregoing method, the replicate of the bone is a rapidly prototyped model of the bone. 
         [0006]    In a further non-limiting embodiment of either of the foregoing methods, the method includes obtaining a radiographical image of the bone, communicating the radiographical image to a computer system to generate a 3D model of the bone, and communicating the 3D model to a rapid prototyping system to create the replicate of the bone. 
         [0007]    In a further non-limiting embodiment of any of the foregoing methods, the method includes practicing a surgical procedure on the replicate of the bone prior to performing the steps of arthroscopically positioning the graft and securing the graft to the bone. 
         [0008]    In a further non-limiting embodiment of any of the foregoing methods, the graft is an acellular dermal extracellular matrix. 
         [0009]    In a further non-limiting embodiment of any of the foregoing methods, the method includes creating a bleeding bone bed on the articulating surface prior to the step of arthroscopically positioning the graft. 
         [0010]    In a further non-limiting embodiment of any of the foregoing methods, the method includes applying a bone marrow concentrate between the graft and the articulating surface after the step of securing the graft to the bone. 
         [0011]    In a further non-limiting embodiment of any of the foregoing methods, the at least one suture anchor is a knotless suture anchor. 
         [0012]    In a further non-limiting embodiment of any of the foregoing methods, the step of arthroscopically positioning the graft includes attaching a plurality of flexible strands to the graft and passing the graft into a joint space surrounding the bone using the plurality of flexible strands. 
         [0013]    In a further non-limiting embodiment of any of the foregoing methods, the step of passing the graft into the joint space includes shuttling the plurality of flexible strands through tunnels formed in the bone using a shuttling device. 
         [0014]    In a further non-limiting embodiment of any of the foregoing methods, the bone is a patella bone and the method includes passing a plurality of flexible strands through the graft, shuttling the plurality of flexible strands one by one into a joint space surrounding the patella bone, extracting free ends of each of the plurality of flexible strands through skin, pulling the graft into place against the articulating surface using the plurality of flexible strands and anchoring the graft to the patella bone using the at least one suture anchor. 
         [0015]    In a further non-limiting embodiment of any of the foregoing methods, the bone is a talus bone and the method includes preparing crossing tunnels through the talus bone, passing sutures through the crossing tunnels, pulling the graft into place against the articulating surface of the talus bone using the sutures and anchoring the graft to the talus bone using the at least one suture anchor. 
         [0016]    A method for resurfacing a bone according to another exemplary aspect of the present disclosure includes, among other things, distracting a bone from a joint, arthroscopically passing a graft into the joint, positioning the graft against an articulating surface of the bone, and fixating the graft to the bone using at least one suture anchor. 
         [0017]    In a further non-limiting embodiment of the foregoing method, the step of distracting the bone from the joint includes inserting a second suture anchor into the bone, connecting a flexible strand that is attached to the suture anchor to a limb positioner, and moving the limb positioner to distract the bone from the joint. 
         [0018]    In a further non-limiting embodiment of either of the foregoing methods, the step of connecting the flexible strand includes looping the flexible strand over an arm of the limb positioner. 
         [0019]    In a further non-limiting embodiment of any of the foregoing methods, the step of moving the limb positioner includes pivoting the arm of the limb positioner between a first position and a second position. 
         [0020]    In a further non-limiting embodiment of any of the foregoing methods, the articulating surface is a posterior articulating surface of the bone. 
         [0021]    A surgical system according to another exemplary aspect of the present disclose includes, among other things, a limb positioner, a suture anchor and at least one flexible strand connected between an arm of the limb positioner and the suture anchor, the arm movable between a first position and a second position to distract a first bone away from a second bone. 
         [0022]    In a further non-limiting embodiment of the foregoing surgical system, the limb positioner includes a body, the arm, an adjustment device and a stand. 
         [0023]    In a further non-limiting embodiment of either of the foregoing surgical systems, the adjustment device is movable to pivot the arm. 
         [0024]    The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible. 
         [0025]    The various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  illustrates a joint of a human musculoskeletal system. 
           [0027]      FIG. 2  schematically illustrates a rapid prototyping technique for creating a bone replicate of the bone that is to be resurfaced. 
           [0028]      FIG. 3  schematically illustrates sizing a graft for resurfacing a bone. 
           [0029]      FIG. 4  schematically illustrates preparing a bone for receiving the graft of  FIG. 3 . 
           [0030]      FIG. 5  illustrates the positioning of a drill guide on a bone during a bone resurfacing procedure. 
           [0031]      FIGS. 6A and 6B  illustrate the formation of bone tunnels and the passing of sutures through a bone during a bone resurfacing procedure. 
           [0032]      FIG. 7  illustrates preparation of a graft for positioning the graft against a surface of a bone during a bone resurfacing procedure. 
           [0033]      FIG. 8  schematically illustrates the positioning of a graft against an articulating surface of a bone during a bone resurfacing procedure. 
           [0034]      FIG. 9  schematically illustrates securing of the graft to a bone during a bone resurfacing procedure. 
           [0035]      FIG. 10  illustrates application of a bone marrow concentrate to a resurfaced bone. 
           [0036]      FIG. 11  illustrates another joint of a human musculoskeletal system. 
           [0037]      FIG. 12  schematically illustrates distraction of a bone of a joint. 
           [0038]      FIGS. 13A and 13B  illustrate a surgical system for distracting a bone of a joint. 
           [0039]      FIG. 14  schematically illustrates preparing a bone for receiving a graft during a bone resurfacing procedure. 
           [0040]      FIGS. 15A and 15B  schematically illustrate preparation of a graft for positioning the graft against a surface of a bone during a bone resurfacing procedure. 
           [0041]      FIG. 16  schematically illustrates shuttling a flexible strand into a joint space during a bone resurfacing procedure. 
           [0042]      FIG. 17  schematically illustrates passing a graft into a joint space during a bone resurfacing procedure. 
           [0043]      FIG. 18  illustrates securing the graft to an articulating surface of the bone during a bone resurfacing procedure. 
           [0044]      FIG. 19  illustrates application of a bone marrow concentrate to a resurfaced bone. 
       
    
    
     DETAILED DESCRIPTION 
       [0045]    This disclosure describes surgical methods for resurfacing portions of arthritic or diseased bone. The resurfacing techniques include passing a graft into a joint and fixating the graft against an articulating surface of a bone of the joint. The resurfacing techniques may be performed to decrease pain and increase functionality of any joint of a musculoskeletal system. 
         [0046]    In some non-limiting embodiments, the surgical methods include sizing a graft, arthroscopically positioning the graft against an articulating surface of the bone, and then securing the graft to the bone. In other non-limiting embodiments, the graft is secured to the bone using one or more suture anchors. In still other non-limiting embodiments, the graft is passed into a joint space and positioned relative to the bone using sutures. These and other features are described in detail in the following paragraphs of this detailed description. 
         [0047]      FIG. 1  illustrates a joint  10  of the human musculoskeletal system. The joint  10  may be any joint found in the musculoskeletal system of the human body. In a non-limiting embodiment, the joint  10  is an ankle joint that includes a tibia  12  and a talus  14  that supports the tibia  12 . Other bones may be associated with the ankle joint, including but not limited to, the calcaneus  15 , the cuboid  17  and the fibula  19 . The talus  14  acts as the primary load bearing surface for transferring loads from the tibia  12  through the entire foot. Because of this, over time, arthritis may develop on the talus  14 , such as at an articulating surface  16  of the talus  14 . 
         [0048]    This disclosure describes resurfacing techniques for resurfacing bone, such as the talus, the patella (see  FIG. 11 ) or any other bone, in order to reduce the pain associated with arthritis. The arthritis may be caused by repetitive trauma to the joint  10 , such as may be experienced during sporting activities. Although resurfacing of the talus and patella are described throughout this disclosure as example resurfacing techniques, this disclosure is not intended to be limited to such embodiments. In other words, the various techniques and instrumentation described herein may be used to resurface any bone of any joint of the human musculoskeletal system. 
         [0049]      FIGS. 2-10 , with continued reference to  FIG. 1 , schematically illustrate an exemplary bone resurfacing procedure. In one non-limiting embodiment, the bone resurfacing procedure is an arthroscopic procedure. The exemplary bone resurfacing procedure is one option for treating end stage arthritis in a patient. Prior to performing the bone resurfacing procedure, appropriate radiological studies may be conducted to determine the grade of the arthritis that has developed on the bone. Excessive arthritis, such as arthritis of grades IV and higher, may require more aggressive procedures than those proposed herein. 
         [0050]    In one non-limiting embodiment, a replicate of the bone that requires resurfacing may be created to aid in planning and executing the bone resurfacing procedure. As shown in  FIG. 2 , a radiographical image  21  may be obtained of the bone that is to be resurfaced, which in this example is the talus  14 . The radiographical image  21  could be obtained using computed tomography (CT), magnetic resonance imaging (MRI) or any other imaging technique. 
         [0051]    The radiographical image  21  may next be communicated for additional processing. For example, the radiographical image  21 , and its underlying data, could be sent to a computer system  23  equipped with appropriate modeling software for processing the radiographical image  21 . Processing may include subtracting non-critical elements and noise from the radiographical image  21 , smoothing or modifying surface features, etc., to generate a 3D model  25  of the talus  14 . 
         [0052]    The 3D model  25  can be sent to a rapid prototyping system  27  to create a bone replicate  29  of the talus  14 . The 3D model  25  provides the necessary numerical data for manufacturing the bone replicate  29 . The rapid prototyping system  27  could be a stereolithography (SLA) system or any other rapid prototyping system. In one non-limiting embodiment, the rapid prototyping system  27  utilizes a powder resin that is selectively sintered by a laser of the rapid prototyping system  27  in a layer-by-layer fashion to generate the bone replicate  29 . The bone replicate  29  can be made from a plastic material or any other suitable material. 
         [0053]    Once created, the bone replicate  29  can be used to plan and execute the bone resurfacing technique. For example, referring now to  FIGS. 1, 2 and 3 , a graft  18  may be sized and shaped to generally match the articulating surface  16  of the talus  14  using the bone replicate  29 . The bone replicate  29  can also be used to practice drilling and fixation methods by using trial grafts. Alternatively, in another non-limiting embodiment, a CT scan or other computerized image of the patient&#39;s joint  10  may be used to estimate the size and shape of the graft  18 . 
         [0054]    Various cutting lines  20  may be marked on the graft  18  using a marker or other writing utensil to outline the desired shape of the graft  18 . The graft  18  may then be cut to the desired size and shape using any known cutting device or cutting methodology. In another non-limiting embodiment, the radiographical image  21  can be used to model and create a patient specific cutting jig/device to precisely cut the graft  18  to a desired shape to enable the surgeon to quickly create the desired shape intraoperatively. The cutting jig/device could be marked circumferentially with reference features or numbers that would correspond to the portions of the graft  18  that require stitching so that marking the graft  18  and anchoring alignment would be facilitated once inserted into the joint. Alternatively, in another non-limiting embodiment, a tissue bank could create and send the precise shaped graft  18 , customized to the patient, to the surgical facility for use during surgery. 
         [0055]    In one non-limiting embodiment, the graft  18  is an acellular dermal extracellular matrix. ArthroFlex®, sold by Arthrex, Inc., is one type of graft suitable for use in the exemplary bone resurfacing procedures of this disclosure. 
         [0056]    The articulating surface  16  of the talus  14  is next prepared for receiving the graft  18 . As shown in  FIG. 4 , the talus  14  may be prepped by performing bone marrow stimulation. For example, a microfracture procedure or some other technique may be performed to obtain a bleeding bone bed  22 . During the microfracture surgery, multiple perforations  24  are created on the articulating surface  16  of the talus  14 . The bleeding bone bed  22  may be created using a tool  26 , such as Arthrex&#39;s Powerpick™, to create the perforations  24 . Formation of the perforations  24  creates the bleeding bone bed  22 , which stimulates bone marrow seepage at the repair site. In another non-limiting embodiment, the bleeding bone bed  22  may be created via abrasion arthroplasty or by debriding the bone surface using a mechanized burr. Other techniques can also be used to create the bleeding bone bed  22 , including but not limited to, drilling, hammering, curetting, scraping, etc. 
         [0057]    In another non-limiting embodiment, the talus  14  may optionally be further prepared for receiving the graft  18  by debriding the articulating surface  16 . The debriding procedure may be performed using another tool  28 , such as Arthrex&#39;s PowerRasp™. 
         [0058]      FIG. 5  illustrates the positioning of a drill guide  30  relative to the talus  14 . The drill guide  30  may include a bracket  32 , an arm  34  rotatable relative to the bracket  32  and a cannula guide  36  moveable within a slot  38  of the bracket  32 . A cannula  40  may be received through the cannula guide  36  and a marking hook  42  may extend from the arm  34 . In one non-limiting embodiment, the drill guide  30  is positioned relative to the talus  14  by seating a distal hook  44  of the marking hook  42  on a posterior rim  46  of the talus  14  at a location just below the articulating surface  16 . The cannula  40  may be positioned at a desired location of the medial rim  48  of the talus  14  by moving the cannula guide  36  within the slot  38  of the bracket  32 . 
         [0059]    Referring now to  FIGS. 5 and 6A , a drill  50  may be inserted through the cannula  40  to prepare tunnels  52 A,  52 B through the talus  14  beneath the articulating surface  16  (see  FIG. 6A ). Although not shown, a depth sleeve may be used in conjunction with the cannula  40  to control the depth of insertion of the drill  50  up to the distal hook  44  of the marking hook  42 . In one non-limiting embodiment, the tunnels  52 A,  52 B are transosseous or crossing drill tunnels. For example, one of the tunnels  52 A,  52 B may exit from the posteriomedial corner of the talus  14 , whereas the other of the tunnels  52 A,  52 B may exit from the posteriolateral corner of the talus  14 . 
         [0060]    As shown in  FIG. 6B , a shuttling device  54  may be passed through each of the tunnels  52 A,  52 B. In one non-limiting embodiment, the shuttling devices  54  are lassos made of either wire or suture. In another non-limiting embodiment, portions of the shuttling devices  54  are stiffened to simply passage of the shuttling devices  54  through the tunnels  52 A,  52 B. Each shuttling device  54  may include looped ends  56 . The shuttling devices  54  may be advanced through a cannulation (not shown) of the drill  50  and then fed through the tunnels  52 A,  52 B from the anterior direction toward the posterior direction. Other insertion techniques may also be utilized. The looped ends  56  of the shuttling devices  54  that exit the tunnels  52 A,  52 B on the posterior side of the talus  14  may then be retrieved through an arthroscopic portal for subsequent use to position the graft  18  within the joint space. 
         [0061]      FIG. 7  illustrates preparation of the graft  18  for its passing into the joint space to resurface the articulating surface  16  of the talus  14 . A plurality of flexible strands  58 A,  58 B may be attached to the graft  18  to aid in the placement of the graft  18  over the articulating surface  16  of the talus  14 . In one non-limiting embodiment, the flexible strands  58 A are suture tapes and the flexible strands  58 B are sutures. The flexible stands  58 A may be attached to each corner of the graft  18 , and one or more of the flexible strands  58 B may be attached to the graft between the flexible strands  58 B along a periphery of the graft  18 . The flexible strands  58 A aid in passing the graft  18  into the joint space, and the flexible strands  58 B provide additional fixation options. Other suture configurations than shown in  FIG. 7  are contemplated within the scope of this disclosure. 
         [0062]    Referring now to  FIG. 8 , the graft  18  may be pulled into place within the joint space using the shuttling devices  54  and the flexible strands  58 A. In one non-limiting embodiment, ends of each flexible strand  58 A are looped through one of the looped ends  56  of the shuttling devices  54 . The opposite looped ends  56  from those receiving the flexible strands  58 A are then pulled to shuttle the flexible strands  58 A into the tunnels  52 A,  52 B and thereby pull the graft  18  into place over the talus  14 . Prior to pulling the flexible strands  58 A into the place, the graft  18  may be partially folded to ease insertion through a small incision, which may be an anterolateral or anteromedial incision. Once the graft  18  is fully seated on the talus  14 , anatomic coverage of the graft  18  may be confirmed arthroscopically. In another non-limiting embodiment, intra-portal atraumatic capsular and soft tissue retraction methods and devices, such as soft cannulas, percutaneous retraction stitches, flexible cannulas, etc., are used to lift away soft tissue from the work area and create space for graft introduction and manipulation followed by bone preparation and graft anchoring. 
         [0063]      FIG. 9  illustrates fixation of the graft  18  to the talus  14  using one or more suture anchors  94 . The graft  18  may be affixed to the articulating surface  16  of the talus  14  after confirming proper seating of the graft  18 . The suture anchors  94  may be any suture anchor type or combination of suture anchors types. In one non-limiting embodiment, the suture anchors  94  are knotless suture anchors. 
         [0064]    Holes  96  may optionally be pre-formed around a periphery of the talus  14  and below the edge of the graft  18  for receiving the suture anchors  94 . Each hole  96  is configured to receive one of the suture anchors  94 . A drill and other tools may be used to form the holes  96 . 
         [0065]    Next, the flexible strands  58 A are loaded through a portion  98  of the suture anchor  94 . The suture anchors  94  may be passed into the joint space via an arthroscopic portal  99 . In one non-limiting embodiment, the portion  98  of the suture anchor  94  includes an eyelet  97 . After receiving the flexible strand  58 A, the eyelet  97  may be inserted into one of the holes  96 . Once the eyelet  97  is positioned at least partially in the hole  96 , the flexible strand  58 A is tensioned in a direction D 1  to approximate the graft  18  to the talus  14 . Next, an anchor body  95  of the suture anchor  94  may be moved toward the eyelet  97  to trap the flexible strand  58 A between the talus  14  and the anchor body  95  in order to fixate the graft  18 . The procedure just described can be repeated to implant multiple suture anchors  94  to fully fixate the graft  18  to the talus  14 . Although suture anchors are illustrated in this embodiment, it should be understood that fixation of the graft  18  could alternatively or additionally be achieved via the use of trans-osseous tunnels to tie suture or other filament over flush fixation devices such as buttons, staples, screws, etc. In yet another non-limiting embodiment, graft to soft tissue anastomosis could be used for fixating the graft  18  to nearby soft tissue connected to the talus  14 . 
         [0066]    In another non-limiting embodiment, as shown in  FIG. 10 , a bone marrow concentrate  90  that has been previously harvested from the patient may be injected under the graft  18  (i.e., between the graft  18  and the articulating surface  16  of the talus  14 ) after the graft  18  has been properly seated. The bone marrow concentrate  90  may be applied using an applicator  92 . Alternatively, the graft  18  may be soaked or impregnated with biologic blood components from the patient prior to inserting and attaching the graft  18  to the talus  14 . 
         [0067]      FIG. 11  illustrates another joint  110  of the human musculoskeletal system. In this non-limiting embodiment, the joint  110  is a knee joint that includes a femur  112 , a tibia  114  and a patella  116 . Various tendons  115  (quadriceps, patellar, etc.) may extend between bones and muscles of the joint  110 . The patella  116  articulates with the femur  112  and covers and protects an anterior articular surface  118  of the femur  112 . Because of this, over time, arthritis and associated loss of articular cartilage may develop on the patella  116 , such as at a posterior articulating surface  120  of the patella  116 . This embodiment describes a resurfacing technique for resurfacing the patella  116  in order to reduce the pain associated with arthritic or diseased bone. 
         [0068]      FIGS. 12-19 , with continued reference to  FIG. 11 , schematically illustrate another exemplary bone resurfacing procedure. In one non-limiting embodiment, the bone resurfacing procedure is an arthroscopic procedure that may be performed through various arthroscopic portals that provide access to an internal joint space. The exemplary bone resurfacing procedure is one option for treating a patient suffering from arthritis. Prior to performing the bone resurfacing procedure, appropriate radiological studies may be conducted to determine the grade of arthritis that has developed within a patient&#39;s joint. Excessive arthritis, such as arthritis of grades IV and higher, may require more aggressive procedures than those proposed herein. 
         [0069]    Referring first to  FIGS. 12, 13A and 13B , the patella  116  may be distracted away from the femur  112  using a surgical system  122 . The patella  116  is distracted away from the femur  112  to gain access to the posterior articulating surface  120 . The posterior articulating surface  120  may need resurfaced because of the development of arthritis. In one non-limiting embodiment, the surgical system  122  includes a limb positioner  124 , a suture anchor  126 , and at least one flexible strand  128  connected between the limb positioner  124  and the suture anchor  126 . The surgical system  122  is configured to apply a vertical force F 1  to the patella  116  to lift it away from the femur  112 . 
         [0070]    In one non-limiting embodiment, the suture anchor  126  is inserted near a center of an anterior surface  130  of the patella  116 . Any type of suture anchor may be used. In addition, although only a single suture anchor is shown in  FIG. 12 , a plurality of suture anchors could be utilized during the exemplary distraction procedure. A pilot hole  132  may optionally be pre-drilled into the patella  116  for inserting the suture anchor  126 . Once inserted, the suture anchor  126  is fixated within the patella  116 . The flexible strand  128 , which may include one or more sutures, may be attached to the suture anchor  126  either before or after its insertion into the pilot hole  132 . 
         [0071]    The flexible strand  128  is next looped over an arm  134  of the limb positioner  124 . The arm  134  may be moved, such as by pivoting, between a first position P 1  and a second position P 2  (shown in phantom in  FIG. 12 ) to distract the patella  116  away from the femur  112 . Because the suture anchor  126  is fixated inside the patella  116 , movement of the arm  134  tensions the flexible strand  128  to apply the vertical force F 1  to the patella  116 . In another non-limiting embodiment, a holding device  136  of the surgical system  122  may optionally be employed to act as a partial counter force during the distraction procedure (see  FIG. 13A ). The holding device  136  may be positioned relative to either the femur  112  or the tibia  114 . 
         [0072]    Additional details of the limb positioner  124  of the surgical system  122  are shown in  FIGS. 13A and 13B . The limb positioner  124  may include a body  138 , the arm  134 , an adjustment device  140  and a stand  142 . The stand  142  includes an attachment device  144  for attaching the limb positioner  124  to a sturdy surface, such as a bed rail. The body  138  is attached to an opposite end of the stand  142  from the attachment device  144 . The arm  134  may be pivotally connected to the body  138 . The adjustment device  140 , which includes a knob  143  and a threaded portion  146 , may be used to change the positioning of the arm  134 . For example, in one non-limiting embodiment, the knob  143  may be turned to advance the threaded portion  146  relative to the body  138 . The threaded portion  146  is connected to an extension  148  of the arm  134 , and the arm  134  is pivoted as the threaded portion  146  is advanced. 
         [0073]    The posterior articulating surface  120  of the patella  116  may be prepared for receiving a graft  150  (see  FIG. 15B ). This may be done any time after distracting the patella  116  from the femur  112 . As shown in  FIG. 14 , the patella  116  may be prepared by performing bone marrow stimulation. For example, a microfracture procedure or some other technique may be performed to obtain a bleeding bone bed  125 . During the microfracture surgery, multiple perforations  135  are created on the posterior articulating surface  120  of the patella  116 . The bleeding bone bed  125  may be created using a tool  145  to create the perforations  135 . Formation of the perforations  135  creates the bleeding bone bed  125 , which stimulates bone marrow seepage at the repair site. Other techniques can also be used to create the bleeding bone bed  125 , including but not limited to, drilling, hammering, curetting, scraping, etc. 
         [0074]    In another non-limiting embodiment, the patella  116  may be further prepared for undergoing resurfacing by debriding the posterior articulating surface  120 . The debriding procedure may be performed using another tool  155 . 
         [0075]    Referring to  FIGS. 15A and 15B , a graft  150  may be sized and shaped to generally match the posterior articulating surface  120  of the patella  116 . In one non-limiting embodiment, the graft  150  is an acellular dermal extracellular matrix. Other graft types are also contemplated. 
         [0076]    In one non-limiting embodiment, the graft  150  is sized and shaped using a bone replicate of the patella  116  that can be manufactured in a manner similar to that shown in  FIG. 2 . In another non-limiting embodiment, the size and shape of the patella  116  is visualized by outlining the patella  116  with a plurality of needles  152 . The actual number of needles  152  used during this procedure could vary from patient to patient and therefore is not intended to limit this disclosure. A flexible strand  154  (shown using dashed lines in  FIG. 15A ) could optionally be wrapped around the outsides of the needles  152 . The length of the flexible strand  154  may then be used to estimate a circumference of the patella  116 . This calculated circumference can then be used to cut the graft  150  to a desired size and shape. In an alternative, non-limiting embodiment, the surface area of the patella  116  (or any other bone) could be arthroscopically visualized and measured using an articulating or extending measuring device. 
         [0077]    As shown in  FIG. 15B , the graft  150  may be placed over the patella  116  (ex-situ) between the needles  152 . Markings  156  may be made around the periphery of the graft  150 . The markings  156  correspond to the locations of the needles  152 . The markings  156  may be made using a marker or any other writing utensil. Flexible strands  158 , such as suture, suture tape, or other strands, may next be passed through the graft  150  at the location of each marking  156 . Any known suture passer may be employed to pass and retrieve the flexible strands  158 . The needles  152  and the flexible strands  158  may be left in place for later use to arthroscopically shuttle the graft  150  into the joint space. 
         [0078]      FIG. 16  schematically depicts arthroscopically shuttling the flexible strands  158  into the joint space. The flexible strands  158  are shuttled into the joint space one by one and are kept separate from one another ex-situ to prevent tangling. In one non-limiting embodiment, the flexible strands  158  are individually passed through an arthroscopic portal  160  to enter the joint space. Free ends  164  of the flexible strands  158  may then be extracted through the patient&#39;s skin  162  at a location of the needle  152  that corresponds to the flexible strand  158  being passed. Various surgical instruments, including but not limited to graspers, elevators, etc., may be used to shuttle and extract the flexible strands  158  in the manner previously described. Once each flexible strand  158  has been passed, the needles  152  are removed. 
         [0079]    After each flexible strand  158  has been shuttled into the joint space, the graft  150  may be pulled into place by pulling each flexible strand  158 . This step is schematically shown in  FIG. 17 . Prior to pulling the flexible strands  158  to position the graft  150 , the graft  150  may be partially folded to ease insertion through a small incision, which may be made laterally or medially. Once the graft  150  is fully seated on the posterior articulating surface  120  of the patella  116 , anatomic coverage of the graft  150  may be confirmed arthroscopically. 
         [0080]      FIG. 18  illustrates fixation of the graft  150  to the patella  116  using one or more suture anchors  166 . The graft  150  may be affixed to the posterior articulating surface  120  of the patella  116  after confirming proper seating of the graft  150 . The suture anchors  166  may be any suture anchor type or combination of suture anchors types. In one non-limiting embodiment, the suture anchors  166  are knotless suture anchors. 
         [0081]    Holes  168  may optionally be pre-formed around a periphery of the patella  116  for receiving the suture anchors  166 . Each hole  168  is configured to receive one of the suture anchors  166 . A drill may be used to form the holes  168  in the patella  116 . 
         [0082]    Next, the free ends  164  of one of the flexible strands  158  are pulled back through the skin and are loaded through a portion  170  of the suture anchor  166 . The suture anchors  166  may be passed into the joint space via an arthroscopic portal  165 . In one non-limiting embodiment, the portion  170  of the suture anchor  166  includes an eyelet  172 . After receiving the free ends  164  of the flexible strand  158 , the eyelet  172  may be inserted into one of the holes  168 . Once the eyelet  172  is positioned at least partially in the hole  168 , the flexible strand  158  is tensioned in a direction D 1  to approximate the graft  150  to the patella  116 . Next, an anchor body  174  of the suture anchor  166  may be moved toward the eyelet  172  to trap the flexible strand  158  between the patella  116  and the anchor body  174  in order to knotlessly fixate the graft  150 . The free ends  164  of the flexible strand  158  may be trimmed flush to the bone. The procedure just described can be repeated to implant multiple suture anchors  166  to fully fixate the graft  150  around the periphery of the patella  116 . 
         [0083]    In another non-limiting embodiment, shown in  FIG. 19 , a bone marrow concentrate  176  that has been previously harvested from the patient may be injected under the graft  150  (i.e., between the graft  150  and the posterior articulating surface  120  of the patella  116 ) after the graft  150  has been fixated. The bone marrow concentrate  176  may be applied using an applicator  178 . Alternatively, the graft  150  may be soaked or impregnated with biologic blood components from the patient prior to inserting and attaching the graft  150  to the patella  116 . In yet another non-limiting embodiment, initial adhesion of the graft  150  to the patella  116  can be augmented by using a biologic glue, such as fibrin glue mixed with ACP or BMA, to accelerate adhesion and reduce the initial suture anchor loads. 
         [0084]    Although the different non-limiting embodiments are illustrated as having specific components, the embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments. 
         [0085]    It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed and illustrated in these exemplary embodiments, other arrangements could also benefit from the teachings of this disclosure. 
         [0086]    The foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. For these reasons, the following claims should be studied to determine the true scope and content of this disclosure.