Patent Publication Number: US-11660194-B1

Title: Cartilage and bone harvest and delivery system and methods

Description:
TECHNICAL FIELD 
     The present disclosure relates to systems, methods and devices for bone and cartilage harvesting and delivery. The present disclosure further relates to systems, methods and devices for the repair of osteochondral defects and bone defects. 
     BACKGROUND 
     Most surgical repairs of osteochondral lesions (i.e., bone-cartilage lesions) are performed using an antegrade approach, meaning that the approach is from the cartilage side of the bone-cartilage defect. In many cases, because of the location of the lesion, these surgical repairs cannot be performed using an arthroscopic or minimally invasive technique; instead, these surgical repairs require an open procedure, increasing morbidity and the time required to recover from the surgery. 
     Another limitation of current surgical techniques for osteochondral lesion repair is the use of autograft or allograft osteochondral “plugs,” in which the plug is an intact specimen of cartilage with underlying bone taken from a single anatomic site. In the case of autograft osteochondral plugs, there are limitations to the size and number of plugs available in a patient. Furthermore, there is a notable risk of morbidity at the plug harvest site, such as post-operative pain and arthritic changes at the harvest site. In the case of allograft osteochondral plugs, there is a risk of an adverse immunological response as well as a risk of disease transmission. 
     Using a retrograde approach to surgically repair an osteochondral lesion, where the approach is from the bone side of the cartilage-bone defect, has several advantages over an antegrade approach. One major advantage is that the retrograde approach can be performed arthroscopically. Another advantage is the opportunity to use the bone and cartilage that is removed to obtain access to the lesion as autograft material for the repair. Existing retrograde approaches are technically demanding and rarely used in clinical practice. 
     There is a need for a simpler, more reproduceable, more reliable surgical technique for a retrograde approach for repairs of osteochondral lesions. Additionally, there is a need for alternative osteochondral graft materials that avoid the risks and complications associated with the use of autograft or allograft osteochondral plugs. 
     SUMMARY 
     The various bone and cartilage harvesting and delivery devices, systems, and methods of the present disclosure have been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available bone and cartilage harvesting and delivery devices, systems, and methods. In some embodiments, the bone and cartilage harvesting and delivery devices, systems, and methods of the present disclosure may provide improved bone and cartilage harvesting and delivery methods for treating bone, cartilage and osteochondral defects. 
     According to some embodiments, a system for harvesting tissue material, including bone and cartilage tissue, from a body, may include a rotary cutter defining a rotary cutter longitudinal axis extending between a rotary cutter proximal end and a rotary cutter distal end. The rotary cutter may have a drive shaft configured to receive input torque, and an osteochondral cutter configured to cut tissue and receive the tissue material in response to rotation of the osteochondral cutter under pressure against the tissue. The system may further have a bone port defining a bone port longitudinal axis extending between a bone port proximal end and a bone port distal end. The bone port may have a bone port cannulation sized to closely fit over the osteochondral cutter. At least one of the bone port proximal end and the bone port distal end may be securable to a bone. 
     The system may further include a plurality of additional rotary cutters, each of which comprises an osteochondral cutter having an outer diameter different from an outer diameter of the rotary cutter, and a plurality of additional bone ports, each of which comprises a bone port cannulation sized to closely fit over the osteochondral cutter of one of the plurality of additional rotary cutters. 
     The bone port distal end may be configured to be insertable into and retained in the bone. 
     The system may further include a bone pin comprising a distal end insertable into the bone. The bone port proximal end may have a pin aperture sized to receive the bone pin to secure the bone port proximal end to the bone. 
     The system may further include a delivery tube defining a delivery tube longitudinal axis extending between a delivery tube proximal end and a delivery tube distal end. The delivery tube distal end may be securable to the bone port proximal end such that the delivery tube longitudinal axis is coaxial with the bone port longitudinal axis. 
     The system may further include a funnel with a funnel proximal end having a flared shape, and a funnel distal end securable to the bone port and/or the delivery tube. 
     The system may further include a cap securable to the bone port proximal end. The cap may have a cap port configured to allow instruments to pass through the cap port while maintaining a leak resistant seal. 
     The system may further include a trial with a trial shaft with a trial shaft proximal end with a handle, and a trial shaft distal end insertable into the bone port cannulation, and a trial tip and configured to approximate a topography of a cartilage or bone surface. The bone port cannulation may be sized to closely fit over the trial tip. 
     The system may further have a plurality of additional rotary cutters, each of which has an osteochondral cutter having an outer diameter different from an outer diameter of the osteochondral cutter, a plurality of additional trial shafts, each of which has a trial shaft distal end, and a plurality of additional bone ports, each of which has a bone port cannulation sized to closely fit over the osteochondral cutter of one of the plurality of additional rotary cutters and to closely fit over the trial shaft distal end of one of the plurality of additional trial shafts. The system may further include a plurality of additional trial tips, each of which is attachable to the trial shaft distal end. 
     The plurality of additional trial tips may include at least a first trial tip with a first trial tip distal surface having a first shape, a second trial tip with a second trial tip distal surface having a second shape different from the first shape, and a third trial tip with a third trial tip distal surface having a third shape different from the first shape and the second shape. 
     The rotary cutter, the plurality of additional rotary cutters, the bone port, and the plurality of additional bone ports may all be configured to be reusable. The trial shaft, the plurality of additional trial shafts, the trial tip, and the plurality of additional trial tips may all be configured to be single-use. 
     The system may further have a trial with a trial shaft with a trial shaft proximal end having a handle, and a trial shaft distal end insertable into the bone port cannulation, and a trial tip attachable to the trial shaft distal end and configured to approximate a topography of a cartilage surface. The bone port may have orientation markings. At least one of the trial shaft and the trial tip may have a trial timing mark that can be aligned with the orientation markings to orient a tissue graft at a predetermined orientation relative to a graft site in which the tissue graft is to be placed. 
     According to some embodiments, a system for delivering a tissue graft to a graft site in a bone may have a bone port defining a bone port longitudinal axis extending between a bone port proximal end and a bone port distal end. The bone port may have a bone port cannulation. The system may further include a trial with a trial shaft having a trial shaft proximal end comprising a handle, and a trial shaft distal end insertable into the bone port cannulation, and a trial tip configured to approximate a topography of a cartilage surface. The bone port cannulation may be sized to closely fit over the trial shaft distal end and the trial tip. At least one of the bone port proximal end and the bone port distal end may be securable to the bone. 
     The bone port distal end may be configured to be insertable into and retained in the bone. 
     The system may further include a bone pin with a distal end insertable into the bone. The bone port proximal end may have a pin aperture sized to receive the bone pin to secure the bone port proximal end to the bone. 
     The system may further include a delivery tube defining a delivery tube longitudinal axis extending between a delivery tube proximal end and a delivery tube distal end. The delivery tube distal end may be securable to the bone port proximal end such that the delivery tube longitudinal axis is coaxial with the bone port longitudinal axis. 
     The system may further include a plurality of additional trial tips including a first trial tip with a first trial tip distal surface oriented at a first angle, a second trial tip with a second trial tip distal surface oriented at a second angle different from the first angle, and a third trial tip with a third trial tip distal surface oriented at a third angle different from the first angle and the second angle. 
     The bone port may have orientation markings. At least one of the trial shaft and the trial tip may have a trial timing mark that can be aligned with the orientation markings to orient the tissue graft at a predetermined orientation relative to a graft site in which the tissue graft is to be placed. 
     According to some embodiments, a system for preparing a tissue graft for insertion in a bone may include a delivery tube defining a delivery tube proximal end and a delivery tube distal end, a tamp with a tamp distal end insertable into the delivery tube proximal end, a base securable to the delivery tube distal end, and a plurality of trial tips, each of which is attachable to at least one of the base and the delivery tube distal end. The delivery tube may be sized to fit closely over the tamp distal end and each trial tip of the plurality of trial tips. The plurality of trial tips may include at least a first trial tip with a first trial tip distal surface having a first shape, a second trial tip with a second trial tip distal surface having a second shape different from the first shape, and a third trial tip with a third trial tip distal surface having a third shape different from the first shape and the second shape. 
     Each of the plurality of trial tips may be attachable to the base, and the base may be attachable to the delivery tube distal end. 
     The system may further include a bone port defining a bone port longitudinal axis extending between a bone port proximal end and a bone port distal end. The bone port may have a bone port cannulation sized to closely fit around the tissue graft. At least one of the bone port proximal end and the bone port distal end may be securable to the bone. The delivery tube distal end may be securable to the bone port proximal end. 
     The bone port may have orientation markings. The delivery tube may have a trial timing mark that can be aligned with the orientation markings to orient the tissue graft at a predetermined orientation relative to a graft site in which the tissue graft is to be placed. 
     According to some embodiments, a system for harvesting tissue material from a body, preparing a tissue graft, and delivering the tissue graft to a graft site, may include a first rotary cutter defining a rotary cutter longitudinal axis extending between a rotary cutter proximal end and a rotary cutter distal end. The first rotary cutter may have a drive shaft configured to receive input torque, and an osteochondral cutter configured to cut tissue and receive the tissue material in response to rotation of the osteochondral cutter under pressure against the tissue. The system may further include a bone port defining a bone port longitudinal axis extending between a bone port proximal end and a bone port distal end, the bone port comprising a bone port cannulation, a delivery tube defining a delivery tube proximal end and a delivery tube distal end, a base securable to the delivery tube distal end, and a trial. The trial may include a trial shaft with a trial shaft proximal end with a handle, and a trial shaft distal end. The trial may further include a trial tip attachable to the trial shaft distal end, and a plurality of additional trial tips, each of which is attachable to the base and to the trial shaft distal end. At least one of the bone port proximal end and the bone port distal end may be securable to a bone. The bone port cannulation may be sized to closely fit over the trial tip and the osteochondral cutter. The delivery tube may be sized to fit closely over the trial shaft distal end and each trial tip of the plurality of additional trial tips. The plurality of additional trial tips may include at least a first trial tip with a first trial tip distal surface having a first shape, a second trial tip with a second trial tip distal surface having a second shape different from the first shape, and a third trial tip with a third trial tip distal surface having a third shape different from the first shape and the second shape. 
     According to some embodiments, a method of treating an osteochondral defect may include determining a local cartilage topography or a local subchondral bone topography surrounding a perimeter of an osteochondral defect, wherein the perimeter is circumscribed by a tunnel with a retrograde approach through a bone and through the osteochondral defect, and delivering a stratiform osteochondral graft, including a bone graft material and a tissue graft material, to the perimeter through the tunnel using the retrograde approach such that a surface of the tissue graft material closely matches the local cartilage topography or the local subchondral bone topography. 
     The bone graft material may be selected from the group consisting of autograft bone, allograft bone, xenograft bone, demineralized bone matrix, bone graft substitutes, extracellular matrix, bone cells, growth factors, blood derivatives, bone marrow aspirate, synthetic bone, and combinations thereof. 
     The tissue graft material may be selected from the group consisting of autograft cartilage, allograft cartilage, xenograft cartilage, extracellular matrix, tissue scaffolds, cartilage cells, cell sheets, biological glues, growth factors, blood derivatives, bone marrow aspirate, synthetic cartilage, and combinations thereof. 
     The method may further include, prior to delivering the stratiform osteochondral graft to the perimeter, fabricating the stratiform osteochondral graft by shaping the stratiform osteochondral graft such that, with the stratiform osteochondral graft in the tunnel, the surface is positionable to match the local cartilage topography or the local subchondral bone topography. 
     Fabricating the stratiform osteochondral graft may further include shaping the bone graft material such that a surface of the bone graft material closely matches the local cartilage topography or the local subchondral bone topography. 
     Determining the local cartilage topography or the local subchondral bone topography may include inserting a trial into the tunnel, the trial having a distal surface, advancing the trial through the tunnel until the distal surface aligns with the local cartilage topography or the local subchondral bone topography, and confirming that the distal surface is shaped to match the local cartilage topography or the local subchondral bone topography. 
     Determining the local subchondral bone topography may include inserting a trial into the tunnel, the trial having a distal edge around the distal surface, advancing the trial through the tunnel until the distal edge of the distal surface aligns with the circumferential edge of the subchondral bone, which is in intimate contact with the circumferential edge of the cartilage, and confirming that the distal edge is shaped to match the local subchondral bone topography. 
     The trial may have a trial shaft and a trial tip with the distal surface. The method may further include, prior to inserting the trial into the tunnel, selecting the trial tip from a plurality of trial tips that are matable with the trial shaft. The plurality of trial tips may include a plurality of distal surfaces of different shapes and/or orientations. The method may further include mating the trial tip to the trial shaft. 
     Fabricating the stratiform osteochondral graft may include shaping the tissue graft material to match the distal surface of the trial. 
     Fabricating the stratiform osteochondral graft may include compressing the bone graft material and/or the tissue graft material in a delivery tube. Delivering the stratiform osteochondral graft to the perimeter may include connecting the delivery tube, containing the stratiform osteochondral graft, to the tunnel, and moving the stratiform osteochondral graft out of the delivery tube and into the tunnel. 
     The method may further include attaching a bone port proximal end and/or a bone port distal end of a bone port to the bone. Delivering the stratiform osteochondral graft to the perimeter may include inserting the stratiform osteochondral graft through the bone port. 
     According to some embodiments, a method of fabricating a stratiform osteochondral graft to treat an osteochondral defect may include determining a local cartilage topography or a local subchondral bone topography surrounding a perimeter of the osteochondral defect, shaping a bone graft material, positioning a tissue graft material adjacent to the bone graft material, and causing a surface of the tissue graft material to match the local cartilage topography or the local subchondral bone topography. 
     The bone graft material may be selected from a group consisting of autograft bone, allograft bone, xenograft bone, demineralized bone matrix, bone graft substitutes, extracellular matrix, bone cells, growth factors, blood derivatives, bone marrow aspirate, synthetic bone, and combinations thereof. 
     The tissue graft material may be selected from a group consisting of autograft cartilage, allograft cartilage, xenograft cartilage, extracellular matrix, tissue scaffolds, cartilage cells, cell sheets, biological glues, growth factors, blood derivatives, bone marrow aspirate, synthetic cartilage, or combinations thereof. 
     Shaping the bone graft material may include causing a surface of the bone graft material to match the local cartilage topography or the local subchondral bone topography. 
     Shaping the bone graft material may include compressing the bone graft material with a first compression force. Causing the surface of the tissue graft material to match the local cartilage topography or the local subchondral bone topography may include compressing the tissue graft material with second compression force. The first compression force may be higher than the second compression force. 
     Causing the surface of the tissue graft material to match the local cartilage topography or the local subchondral bone topography may include causing a bone graft material surface of the bone graft material to match the local subchondral bone topography, and causing a tissue graft material surface of the tissue graft material to match the local cartilage topography. 
     According to some embodiments, a method of delivering a stratiform osteochondral graft to a bone tunnel in a bone may include attaching a bone port proximal end and/or a bone port distal end of a bone port to the bone, attaching a delivery tube distal end of a delivery tube to the bone port proximal end, the delivery tube containing a stratiform osteochondral graft, and delivering the stratiform osteochondral graft to the bone tunnel from the delivery tube through the bone port. 
     The method may further include, after delivering the stratiform osteochondral graft to the bone tunnel, moving the stratiform osteochondral graft through the bone tunnel such that a surface of the stratiform osteochondral graft matches a local cartilage topography or a local subchondral bone topography surrounding an internal opening of the bone tunnel. 
     The method may further include, prior to delivering the stratiform osteochondral graft to the bone tunnel, fabricating the stratiform osteochondral graft by shaping the stratiform osteochondral graft such that, with the stratiform osteochondral graft in the bone tunnel, the surface is positionable to match the local cartilage topography or the local subchondral bone 
     The stratiform osteochondral graft may further include of a bone graft material and a tissue graft material. 
     The bone graft material may be selected from a group consisting of autograft bone, allograft bone, xenograft bone, demineralized bone matrix, bone graft substitutes, extracellular matrix, bone cells, growth factors, blood derivatives, bone marrow aspirate, synthetic bone, and combinations thereof. 
     The tissue graft material may be selected from a group consisting of autograft cartilage, allograft cartilage, xenograft cartilage, extracellular matrix, tissue scaffolds, cartilage cells, cell sheets, biological glues, growth factors, blood derivatives, bone marrow aspirate, synthetic cartilage, or combinations thereof. 
     These and other features and advantages of the present disclosure will become more fully apparent from the following description and appended claims or may be learned by the practice of the devices, systems, and methods set forth hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present disclosure will become more fully apparent from the following description taken in conjunction with the accompanying drawings. Understanding that these drawings depict only exemplary embodiments and are, therefore, not to be considered limiting of the scope of the present disclosure, the exemplary embodiments of the present disclosure will be described with additional specificity and detail through use of the accompanying drawings in which: 
         FIG.  1    is a perspective view of a reusable kit of instruments for tissue harvesting and delivery, according to one embodiment. 
         FIG.  2    is an exploded view of a subset of the instruments shown in  FIG.  1    for a select tissue tunnel size that have shared interconnection features. 
         FIG.  3    is a perspective view of a single use kit of instruments that complement the subset of instruments shown in  FIG.  1    to facilitate a surgical procedure for a select tissue tunnel size. 
         FIG.  4    is a perspective view from a lateral viewpoint of a proximal tibia and a guidewire placed into the tibia and into an osteochondral lesion from a retrograde approach. 
         FIG.  5 A  is a perspective view from a lateral viewpoint of the proximal tibia shown in partial cross section and a trephine placed over the guidewire and into the proximal tibia and through the cartilage from a retrograde approach. 
         FIG.  5 B  is a perspective view from a lateral viewpoint of the proximal tibia shown in partial cross section and an obturator placed over the guidewire and a bone port placed over the obturator and into the proximal tibia. 
         FIG.  6    is a perspective view from a lateral viewpoint of the proximal tibia shown in partial cross section and a trephine inside of a bone port, and the bone port secured to the tibia. 
         FIG.  7    is the view of  FIG.  6    with the trephine removed and a cap attached to a bone port. 
         FIG.  8 A  is a perspective view from a lateral viewpoint of the proximal tibia shown in partial cross section and a trial shaft with an attached angled trial tip placed through a bone portal and with the trial tip distal end positioned to match the surface topography of the surrounding cartilage. 
         FIG.  8 B  is a perspective view from a lateral viewpoint of the proximal tibia shown in partial cross section and a trial shaft with an attached angled trial tip placed through a bone portal and with the trial tip distal end positioned to match the surface topography of the surrounding cartilage. 
         FIG.  9 A  is a perspective view showing a base next to an angled trial tip connected to a trial shaft. 
         FIG.  9 B  is the view of  FIG.  9 A  showing the transfer of an angled trial tip from a trial shaft to a base. 
         FIG.  10 A  is a perspective view showing a delivery tube attached to a base with an assembled angled trial tip positioned in the delivery tube with a tamp inserted into the proximal end. 
         FIG.  10 B  is a close-up view of  FIG.  10 A  with the delivery tube cut away to show bone graft material compacted proximally by a trial and distally by the angled trial tip. 
         FIG.  11    is a perspective view in partial cross-section showing cartilage graft material compacted into the distal end of the delivery tube distally by an angled trial tip to fabricate a stratiform osteochondral graft. 
         FIG.  12    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia showing a loaded delivery tube engaged with a bone port. 
         FIG.  13    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia shown with a tamp pushing the stratiform osteochondral graft into final position. 
         FIG.  14    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia with a bone port secured to the proximal tibia, an enlarged bone defect site located in the proximal tibia, and a funnel attached to the bone port. 
         FIG.  15    is the view of  FIG.  14    showing rotation and pushing of a trial to displace bone graft material into the enlarged bone defect site. 
         FIG.  16    is the view of  FIG.  15    showing a delivery tube loaded with compacted bone graft material, with the delivery tube attached to the bone port. 
         FIG.  17    is the view of  FIG.  16    showing a tamp pushing the compacted bone graft into final position. 
         FIG.  18    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia with an obturator inserted into an existing bone tunnel, and a bone port placed over the obturator. 
         FIG.  19    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia with the bone port secured to the tibia, a delivery tube attached to the bone port, with the delivery tube loaded with compacted bone graft material. 
         FIG.  20    is the view of  FIG.  19    showing a tamp pushing the compacted bone graft material into final position. 
         FIG.  21    is a flow chart showing a method of treating an osteochondral defect, according to one embodiment. 
         FIG.  22    is a flow chart showing a method of fabricating a stratiform osteochondral graft, according to one embodiment. 
         FIG.  23    is a flow chart showing a method of treating a bone defect, according to one embodiment. 
         FIG.  24    is a flow chart showing a method of treating an existing bone tunnel, according to one embodiment. 
     
    
    
     It is to be understood that the drawings are for purposes of illustrating the concepts of the present disclosure and may not be drawn to scale. Furthermore, the drawings illustrate exemplary embodiments and do not represent limitations to the scope of the present disclosure. 
     DETAILED DESCRIPTION 
     Exemplary embodiments of the present disclosure will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of the present disclosure, as generally described and illustrated in the drawings, could be arranged, and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the implants, systems, and methods, as represented in the drawings, is not intended to limit the scope of the present disclosure, but is merely representative of exemplary embodiments of the present disclosure. 
     The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. While the various aspects of the embodiments are presented in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated. 
     The following examples have been included to provide guidance to one of ordinary skill in the art for practicing representative embodiments of the presently disclosed subject matter. In light of the present disclosure and the general level of skill in the art, those of skill in the art can appreciate that the following examples are intended to be exemplary only and that numerous changes, modifications, and alterations can be employed without departing from the scope of the presently disclosed subject matter. 
     For purposes of interpreting this specification, the following definitions will apply. If any definition set forth below conflicts with any document incorporated herein by reference, the definition set forth below shall control. 
     Bone and cartilage, collectively, are referred to as tissue herein. Bone-cartilage defect, osteochondral defect and osteochondral lesion are synonymous, and generally referred to herein as a lesion. Bone marrow edema, focal osteolysis and a bone cyst are generally referred to herein as a bone defect. Proximal means closer to a user, distal means farther away from a user. For example, the handle of a screwdriver is on a proximal end, and the drive tip of a screwdriver is on a distal end. 
       FIG.  1    is a perspective view of a reusable kit of instruments, or system  100 , for tissue harvesting and delivery. The system  100  may include a guidewire  110 , a plurality of trephines  120 , a plurality of bone ports  130 , a plurality of tamps  140 , and a plurality of obturators  150 . The trephines  120 , bone ports  130 , tamps  140 , and obturators  150  are each shown in 5 sizes, ranging from 6 mm to 14 mm in 2 mm increments, where the size is the size of the tissue tunnel to be formed by the selected subset of the system  100 . Other sizes and other increments are possible, for example, ranging from 4 mm to 20 mm in 1 mm increments. 
       FIG.  2    is an exploded view of a subset  200  of the instruments of the system  100  of  FIG.  1    for a select tissue tunnel size that have shared interconnection features. The subset  200  includes the guidewire  110 , a trephine  220 , a bone port  230 , a tamp  240 , and an obturator  250 . The select tunnel size in this case is 10 mm, or the middle size in the range of sizes in the system  100  of  FIG.  1   . 
     The guidewire  110  may be a surgical guide wire of any known type, such as a K-wire or Steinmann Pin. The guidewire  110  may have a guidewire outer diameter  112 . 
     The trephine  220  may have a trephine proximal end  222 , a trephine distal end  224 , a trephine longitudinal axis  225  extending between the trephine proximal end  222  and the trephine distal end  224 , a drive shaft  226  located near the trephine proximal end  222 , and a drive shaft cannulation  227  extending along the trephine longitudinal axis  225 . The guidewire outer diameter  112  may be sized to closely fit inside the drive shaft cannulation  227 , optionally with some clearance so that the trephine  220  can slide along the guidewire  110 . Approaching the trephine distal end  224 , the trephine  220  may have an osteochondral cutter  228  terminating in a set of teeth  229  configured to cut tissue as the trephine  220  is rotated and pressed against tissue, forming a tunnel. The osteochondral cutter  228  may have a trephine outer diameter  223 . The trephine  220  is just one of many different types of rotary cutters that may be used to cut tissue according to the present disclosure. In alternative embodiments, different rotary cutters, such as drills, reamers, and/or augers, may be used in addition to or in place of the trephine  220 . The term “rotary cutter” encompasses all of these alternatives in addition to a trephine. 
     The bone port  230  may have a bone port proximal end  232 , a bone port distal end  234 , a bone port longitudinal axis  235  extending between the bone port proximal end  232  and bone port distal end  234 , and a bone port cannulation  237 . The bone port cannulation  237  may have a bone port inner diameter  233  sized to closely fit over the outer diameter of the osteochondral cutter  228  so that the bone port longitudinal axis  235  and the trephine longitudinal axis  225  are coaxial when the bone port  230  and the trephine  220  are engaged. Further, the bone port  230  may have a pin aperture  238  and a series of orientation markings  239  proximate the bone port proximal end  232 . Teeth  231  on the bone port distal end  234  may help anchor the bone port  230  to bone when tapped or drilled into place. 
     The tamp  240  may have a tamp proximal end  242 , tamp distal end  244 , and a tamp outer diameter  246 . The tamp proximal end  242  may have a handle  247  that is designed to be pressed by hand and/or impacted with a mallet or other instrument to compress graft material at the tamp distal end  244 . A series of depth markings, such as circumferential grooves  249 , may be arranged along the length of the proximal portion of the tamp  240 , and may help the user gauge the motion travelled by the tamp  240  in the course of compacting tissue material, and thence, the degree of compaction applied by the tamp  240  to the tissue material. Additionally, the tamp distal end  244  may be used to move graft material from one position to another. 
     The obturator  250  may have an obturator proximal end  252 , an obturator distal end  254 , and an obturator outer diameter  256 , which may be substantially equal to the trephine outer diameter  223 , the bone port inner diameter  233 , and the tamp outer diameter  246 . The obturator distal end  254  may be tapered to facilitate insertion of the obturator  250  into an opening tissue, such as a pre-existing bone tunnel, in order to widen and/or prepare the opening for further steps. 
     The guidewire  110 , the trephine  220 , the bone port  230 , the tamp  240 , and/or the obturator  250  may be designed for reuse. Thus, these components may be formed of durable and readily sterilizable, and re-sterilizable, materials, such as stainless steel, or any other material known for use in the manufacture of surgical instruments. In alternative embodiments, one or more of these components may be designed for single use, and may thus be formed of less durable materials, such as plastics, if desired. In the present embodiment, the components of the system  100  may be designed for use with a system  300  of single use components. The system  100  and the system  300  may combine to define a system with reusable components (from the system  100 ) and disposable components (from the system  300 ). In some embodiments, the components of the system  100  may be sterilized and provided in a reusable assembly such as a re-sterilizable instrument tray. The components of the system  300  may also be sterilized, but may be provided in disposable, single-use packaging, such as one or more sealed plastic packages. The components of the system  300  may be formed of less expensive less durable materials, such as plastic materials, if desired. Alternatively, some or all of the components of the system  300  may be formed of durable re-sterilizable materials and added to the reusable instrument tray and/or provided separately. 
       FIG.  3    is a perspective view of the system  300 , which may be a single use kit of instruments that complements the system  100  shown in  FIG.  1    to facilitate a surgical procedure for the select tissue tunnel size of 10 mm. Separate systems may be provided for each size tissue tunnel that is desired for treatment. For example, in addition to the system  300 , additional systems (not shown) may be provided along with the system  100  to facilitate treatment using 6 mm, 8 mm, 12 mm, and 14 mm tissue tunnels. The system  300  may include a fixation pin  310 , a plurality of trial tips  320 , a base  330 , a cap  340 , a delivery tube  350 , a funnel  360 , and a trial shaft  370 . 
     Like the guidewire  110 , the fixation pin  310  may be any type of bone pin known in the art. For example, the fixation pin  310  may be a k-wire or the like. The fixation pin  310  may be sized to slide into the pin aperture  238  of the bone port  230 , and may fit sufficiently tightly within the pin aperture  238  such that the bone port  230  is maintained at a constant relative orientation by engagement of the pin aperture  238  with the guidewire  310 . 
     Each of the trial tips  320  may have a trial tip proximal end  322 , a trial tip distal end  324 , and a trial tip outer diameter  326 . Each of the trial tips  320  may further have an attachment feature, such as a slot  327 , that facilitates attachment to the base  330  and/or the trial shaft  370 . Thus, each of the trial tips  320  may be interchangeably attachable to the same male attachment feature. 
     Each trial tip distal end  324  may be planar, but the orientation of the trial tip distal end  324  may vary among the trial tips  320 . The orientation of the trial tip distal end  324  may range, among the trial tips,  320 , from 0° to 50°, measured as the offset from a plane perpendicular to the axis extending from the trial tip proximal end  322  to the trial tip distal end  324 . Each of the trial tips  320  may have an angle indicator  329  that indicates the orientation of the trial tip distal end  324 . 
     In alternative embodiments, different increments may be used; such increments may be greater than or smaller than 5° (for example, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 12.5°, 15°, 20°, 22.5°, or 25°). Further, the orientation of the trial tip distal end  324  need not have a maximum of 50°; a smaller or greater maximum orientation may be used (for example, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, or 80°). In some embodiments, where it is desired to approach an osteochondral defect from an orientation nearly parallel to the cartilage surface, the maximum orientation may approach 90°. 
     In alternative embodiments, the trial tip distal end  324  of the trial tips  320  may have any range of unique shapes, including concave, convex, or even more complex shapes. Additionally or alternatively, the trial tip distal end  324  of each of the trial tips  320  may be shaped to match a specific cartilage topography for a specific osteochondral defect for a specific patient. For trial tip distal ends that are not planar, two trial tips with complementary shapes (not shown) may be used for a specific osteochondral defect. The first trial tip may directly correspond to a cartilage surface when it is used as a trial as shown in  FIG.  8 A  and  FIG.  8 B , and the second trial tip may correspond to the negative (i.e., a Boolean subtraction) of the cartilage surface when it is used to compact bone graft material and cartilage graft material as shown in  FIG.  10 B  and  FIG.  11   . 
     The base  330  may have a body  332 , a plateau  334 , and an attachment feature configured to mate with the slot  327  of the trial tips  320 , such as a slider  337 . The body  332  may have an enlarged shape that can be readily grasped by a user and/or placed on a flat surface during use. The plateau  334  may have a width similar in size to that of the delivery tube  350 . The plateau  334  and/or the slider  337  may optionally be incorporated into an insert, separate from the body  332 , that can be assembled with the body  332  (for example, via insertion of the insert into a hole in the body  332 ) to provide the assembled configuration shown in  FIG.  3   . 
     The cap  340  may be sized to fit over the bone port proximal end  232  and/or the delivery tube proximal end  352 . Thus, the cap  340  may have a bore  344  with an interior diameter (not shown) that is close to the outer diameter of the bone port proximal end  232  and the delivery tube proximal end  352 . The cap  340  may further have a cap port  346  that provides a leak resistant seal. The cap port  346  may be flexible and self-closing, so that instruments can be passed through the cap port  346  and still maintain a leak resistant seal. The cap  340  may be formed of a resilient, flexible material, such as rubber, to help provide a seal between the cap  340  and the bone port proximal end  232  and/or the delivery tube proximal end  352 , and the seal provided by the cap port  346 . 
     The delivery tube  350  may have a delivery tube proximal end  352 , a delivery tube distal end  354 , and a delivery tube longitudinal axis  355  extending between the delivery tube proximal end  352  and delivery tube distal end  354 . The delivery tube distal end  354  may be sized to closely fit into the bone port proximal end  232  so that the delivery tube longitudinal axis  355  and the bone port longitudinal axis  235  are coaxial when the delivery tube  350  and the bone port  230  are coupled together. 
     The funnel  360  may have a funnel proximal end  362 , a funnel distal end  364 , a funnel longitudinal axis  365  extending between the funnel proximal end  362  and funnel distal end  364 . The funnel distal end  364  may be sized to closely fit into the bone port proximal end  232  and/or the delivery tube proximal end  352  and/or delivery tube distal end  354 , so that the funnel longitudinal axis  365  is coaxial with the bone port longitudinal axis  235  or the delivery tube longitudinal axis  355 , respectively. The funnel proximal end  362  may have a flared shape configured to facilitate insertion of graft material and instruments into the funnel  360 , and thence into the bone port  230  and/or delivery tube  350 . 
     The trial shaft  370  may have a trial shaft proximal end  372 , a trial shaft distal end  374 , and a trial shaft outer diameter  376 , which may be substantially equal to the trephine outer diameter  223 , the bone port inner diameter  233 , and the tamp outer diameter  246 . The trial shaft distal end  374  may have an attachment feature, such as a slider  377 , that is designed to mate with the slot  327  of each of the trial tips  320 . The slider  377  may have an enlarged tip and the slot  327  may have a complementary shape so that, when coupled to each other, each of the trial tips  320  cannot be pulled distally away from the trial shaft  370 . The trial shaft  370  may further have a handle  378  at the trial shaft proximal end  372 , and a series of depth markings  379  between the trial shaft proximal end  372  and the trial shaft distal end  374 . 
     The assembled trial shaft  370  and one of the trial tips  320  are referred to as a trial, which may have an outer diameter substantially equal to the tamp outer diameter  246 . To accommodate the select tunnel size of 10 mm, the trephine outer diameter  223  of the osteochondral cutter  228 , the inner diameter of the bone port cannulation  237 , the tamp outer diameter  246 , and the trephine outer diameter  223  may all be nominally 10 mm in size. Those of skill in the art will recognize that some variation from the nominal size may be desirable; for example, the inner diameter of the bone port cannulation  237  may be slightly larger than the trephine outer diameter  223 , the trial tip outer diameter  326 , and the trial shaft outer diameter  376  so that the trephine  220 , each of the trial tips  320 , and/or the trial shaft  370  may be inserted and relatively freely slide into the bone port cannulation  237  of the bone port  230 . 
     While the mating connections between bone port  230 , delivery tube  350 , funnel  360 , and cap  340  are shown with specific male and female arrangements, in alternative embodiments (not shown), the connections can be easily reversed and still preserve the coaxial relationship between respective longitudinal axes required to ensure proper function. Further, many different mating and non-mating connections may be used, including but not limited to clips, claps, mechanical fasteners, bayonet fittings, and/or the like. 
     The system  100  and/or the system  300  may be used to help repair osteochondral defects in bone. In some embodiments, this may be accomplished by (1) harvesting tissue, (2) preparing the harvested tissue, and (3) placing the prepared tissue at the defect site. Notably, this approach assumes that the tissue is natural (i.e., autograft, allograft, or even xenograft). However, the system  100  and/or the system  300  may also be used with synthetic graft or bone graft substitutes; in such cases, (1) and/or (2) above may not be needed. 
     In some embodiments, the process of harvesting the tissue may be formed as part of the process of removing the osteochondral defect and/or preparing the defect site for repair. Healthy tissue at or around the repair site may be removed, prepared, and inserted back into the repair site, optionally with additional natural or synthetic tissue.  FIGS.  4  through  8    illustrate the process of harvesting tissue and preparing a defect site for repair (i.e., step (1) in the preceding paragraph) according to one embodiment. 
       FIG.  4    is a perspective view from a lateral viewpoint of a proximal tibia  400  with the guidewire  110  placed into the proximal tibia  400  and into the central aspect of an osteochondral lesion  410  from a retrograde approach (i.e., through the tissue beneath the osteochondral lesion  410 ). The placement of the guidewire  110  into the bone and cartilage can be accomplished using a powered pin driver (not shown), and the guidewire  110  can be placed manually or using a targeting drill guide (not shown) known in the art. Fluoroscopy and/or other medical imaging may be used to guide placement of the guidewire  110 . In some embodiments, direction visualization (for example, via arthroscopic cameras inserted into the knee joint) may be used to guide and/or confirm placement of the guidewire  110 . 
     The proximal tibia  400  is used in the figures is for illustrative purposes. The systems and methods of the present disclosure may be used to treat any bone and/or cartilage location in the body. Cartilage is found in all the articular joints of the body. In the example of  FIG.  4   , the osteochondral lesion  410  is located in the knee joint. Other articular joints in the body that may be treated with the systems and methods presented herein include, but are not limited to: a metatarsal-phalangeal joint, a metatarsal-tarsal joint, a tarsal-tarsal joint, a subtalar joint, a calcaneal-tarsal joint, an ankle joint, a hip joint, a metacarpal-phalangeal joint, a metacarpal-carpal joint, a carpal-carpal joint, a wrist joint, an elbow joint, a shoulder joint, and spine facet joint. 
       FIG.  5 A  is a perspective view from a lateral viewpoint of the proximal tibia  400  shown in partial cross section and the trephine  220  placed and slid over the guidewire  110  and into the proximal tibia  400  and through the osteochondral lesion  410  from a retrograde approach, forming a tissue tunnel  500  underneath the repair site. The drive shaft cannulation  227  may fit closely over the guidewire  110  such that the trephine  220  tracks precisely to the osteochondral lesion  410 . In an alternative embodiment, a cannulated drill or other cannulated cutter known in the art (not shown) may be used in place of or in addition to the trephine  220  to form the tissue tunnel  500 . The tissue tunnel  500  may extend sufficiently far to include the osteochondral lesion  410 . In this application, the term “tissue tunnel” is intended to cover tunnels through various types of tissue, including but not limited to tunnels through bone, cartilage, and combinations of bone and cartilage. 
     In this example, the tissue tunnel  500  may be approximately 10 mm in size because the trephine outer diameter  223  of the osteochondral cutter  228  may be about 10 mm. Any of the trephines  120  of  FIG.  1    may be used to provide a tissue tunnel of the appropriate size for a particular joint and/or a particular osteochondral defect. 
       FIG.  5 B  is a perspective view from a lateral viewpoint of the proximal tibia  400  shown in partial cross section and an obturator  250  placed over the guidewire  110  and a bone port  230  placed over the obturator  250  and into the proximal tibia  400 . The obturator  250  may be used to facilitate placement of the bone port  230  such that the bone port cannulation  237  is coaxial with the tissue tunnel  500  (not shown). 
       FIG.  6    is the view of  FIG.  5 A  with the bone port  230  placed and slid over the trephine  220  and secured to the proximal tibia  400 .  FIG.  6    is also the view of  FIG.  5 B  with bone port  230  used to guide the trephine  220  into the formation of tissue tunnel  500 . The bone port inner diameter  233  may closely fit over the trephine outer diameter  223  to ensure that the bone port longitudinal axis  235  and the trephine longitudinal axis  225  are coaxial, irrespective of which is placed first. The teeth  231  on the bone port distal end  234  may be serrated and may allow the bone port distal end  234  to be inserted along the bone port longitudinal axis  235  into the bone, thereby securing the bone port  230  to the bone. Alternatively, or in combination with securing of the bone port distal end  234  to the bone, the bone port  230  can be secured to bone adjacent to the bone port proximal end  232 . For example, the pin aperture  238  may receive the fixation pin  310  to secure the bone port  230  to the bone. 
     Notably, the bone port  230  need not necessarily be used to dilate or retract tissue; rather, these steps may be performed with other instruments, such as the obturator  250 , prior to application of the trephine  220 . The trephine  220  may guide placement of the bone port  230  as the bone port  230  may be slid into position over the trephine  220 , or the bone port  230  may guide placement of the trephine  220 . Formation of the tissue tunnel  500  with the trephine  220  prior to attachment of the bone port  230  may facilitate and/or enable the bone port  230  to be used for other functions besides guiding the trephine  220 . For example, the bone port  230  may maintain retraction of the surrounding soft tissue such as muscle, fat and skin (not shown). This may be advantageous for subsequent operative steps, such as visualizing the interior of the tissue tunnel  500  with an endoscope (not shown), removing additional tissue from the interior of the tissue tunnel  500 , accessing an intra-articular space, and/or delivering bone graft materials and/or cartilage graft materials to the repair site through the tissue tunnel  500 . 
       FIG.  7    is the view of  FIG.  6    with the trephine  220  removed. With the trephine  220  removed, a user may attach the cap  340  to the bone port proximal end  232  to form a leak resistant seal to facilitate the performance of an arthroscopic procedure in the knee joint space. The cap port  346  may provide another leak resistant seal when instruments are passed through the cap port  346 . For example, the user can insert an endoscope (not shown) through the cap port  346  and into the tissue tunnel  500  to allow for direct visualization of the cartilage layer and underlying bone to ensure that all the damaged/diseased cartilage and/or bone associated with the osteochondral lesion  410  have been removed. If damaged/diseased cartilage and/or bone remain, then the user can pass a curette or other cutting instrument (not shown) to excavate the remaining damaged/diseased tissue. 
     Loose tissue may be removed from the tissue tunnel  500 . Much of the loose tissue may come out of the tissue tunnel  500  with the removal of trephine  220 . Additional instruments, suction, and/or the like may be used to remove any remaining pieces of bone or cartilage from the tissue tunnel  500 . 
       FIG.  8 A  is a perspective view from a lateral viewpoint of the proximal tibia  400  shown in partial cross section, with the trial shaft  370  and a trial tip  800 , attached to the trial shaft  370 , placed through the bone port  230 . The trial tip  800  may be one of the trial tips  320 , angled at 45°. As shown, the trial tip  800  may be positioned and oriented such that the trial tip distal end  324  is positioned to match the surface topography of the surrounding cartilage and/or bone around the repair site. The trial shaft outer diameter  376  may be approximately 10 mm to provide for a close sliding fit inside the bone port inner diameter  233 . The trial shaft  370  with an attached trial tip such as the trial tip  800  is also referred to herein as a “trial.” 
     The trial tip  800  shown in  FIG.  8    has a surface  810  on the trial tip distal end  324  that is a plane at a 45-degree angle to the bone port longitudinal axis  235 . Users can select from a plurality of trial tips (for example, from the trial tips  320  of  FIG.  3   ) to find the trial tip with a trial tip distal end that is most conformal to the topography of the surrounding cartilage and/or bone. Some trial and error may be needed. In addition to the depth markings  379 , the trial shaft  370  and/or the trial tip  800  have one or more trial timing marks  820  that are used to indicate the circumferential orientation of the trial relative to the bone port  230  as measured against the one or more circumferential timing marks, such as the orientation markings  239  of the bone port  230 . As shown in  FIG.  8   , the circumferential orientation is approximately 55 degrees. 
     The depth markings  379  of the trial shaft  370  may be measured against the bone port proximal end  232  to indicate the depth that the trial tip  800  extends beyond the entry hole into the tissue tunnel  500 , thus allowing measurement of the length of the tissue tunnel  500  when the trial tip distal end  324  is flush with the surrounding cartilage surface. As shown in  FIG.  8 A , the length of the tissue tunnel  500  is approximately 35 mm. The circumferential orientation and the length may be noted by the user in preparation for future steps. 
       FIG.  8 B  is a perspective view from a lateral viewpoint of the proximal tibia  400  shown in partial cross section and a trial shaft  370  with an attached angled trial tip  800  placed through a bone port  230  and with the trial tip distal end  324  positioned to match the surface topography of the surrounding cartilage and/or bone. An optional orientation storage feature may be coupled to the bone port proximal end  232  and used to record the orientation of the trial tip  800  when aligned with the surrounding cartilage. 
     More precisely, the orientation storage feature may include a dial  850  with a generally annular shape that can be rotatably coupled to the bone port proximal end  232 . The dial  850  may have a pointer  852  that can be aligned, via rotation of the dial  850  on the bone port  230 , with the trial timing mark  820  of the trial shaft  370 . When the trial shaft  370  and the trial tip  800  are removed from the bone port  230 , the dial  850  may remain in place to facilitate alignment of the bone graft with the surrounding cartilage, in a manner that matches the alignment of the trial tip  800  with the surrounding cartilage. 
     The dial  850  is an optional feature. It may be used in place of, or in addition to, the orientation markings  239  of the bone port  230 . In some embodiments, the dial  850  may be aligned with the trial timing mark  820  as described above, and then partially removed so that the user can see which of the orientation markings  239  is aligned with the pointer  852 . This orientation may then be recorded for future use without requiring further use of the dial  850 . 
     After performance of the steps illustrated in  FIG.  8 A  and/or  FIG.  8 B , removal of the damaged and/or diseased tissue from the proximal tibia  400  may be complete. All information needed to prepare the replacement tissue may have been obtained. Thus, the user may proceed to prepare the replacement tissue, as will be shown and described in connection with  FIGS.  9 A through  11   . Advantageously, the bone port  230  may remain attached to the tissue tunnel  500  during preparation of the replacement tissue to facilitate the subsequent insertion of the replacement tissue into the graft site. 
       FIG.  9 A  is a perspective view showing the base  330  (with assembled insert, if applicable) next to the trial tip  800  connected to the trial shaft  370 . The base  330  may releasably attach to the trial tip proximal end  322  such that the trial tip distal end  324  faces away from the base  330 . The base  330  may also releasably attach to the delivery tube distal end  354 , for example, at or around the plateau  334 . The base  330  may have a base timing mark  900  that aligns with the trial timing mark  820  on the trial tip  800  when the trial tip  800  is assembled to the base  330 . 
       FIG.  9 B  is the view of  FIG.  9 A  showing the transfer of the trial tip  800  from the trial shaft  370  to the base  330 . The trial tip  800  may releasably connect to each of the trial shaft  370  and the base  330  by sliding the trial tip  800  in from the side of the trial shaft  370  and base  330 , respectively, such that the slot  327  receives the slider  377  of the trial shaft  370  or the slider  337  of the base  330 . However, any other releasable connection feature that resists dislodgement during use may be substituted for the slot  327 , the slider  377 , and the slider  337 . 
       FIG.  10 A  is a perspective view showing the delivery tube  350  attached to the base  330  with the tamp  240  positioned in the delivery tube  350 . The delivery tube  350  has a delivery tube timing mark  1000  and a delivery tube depth scale  1010 . The delivery tube depth scale  1010  and/or the circumferential grooves  249  can be referenced to create a graft having the same length as the previously measured length of the tissue tunnel  500 . When assembled to the base  330 , the delivery tube timing mark  1000  and the trial timing mark  820  may be aligned with the base timing mark  900 . If desired, one of the circumferential grooves  249  may be replaced with a reference line  1030  to show a preferred depth of insertion of the tamp  240 . 
       FIG.  10 B  is a close-up view of  FIG.  10 A  with the delivery tube  350  cut away to show bone graft material compacted proximally by a tamp  240  and distally by the trial tip  800  used to simulate repair of the osteochondral lesion  410  in  FIG.  8    to form a formed end on the compacted bone graft  1020  corresponding to the trial tip distal end  324  of the trial tip  800 . High forces, typically generated by strikes from a surgical mallet, may be applied (for example, to the handle  247  of the tamp  240 ) to fully compact the bone graft material to form the compacted bone graft  1020 . 
       FIG.  11    is a perspective view in partial cross-section of the trial shaft  370  and the delivery tube  350 , showing cartilage graft material  1100  compacted into the delivery tube distal end  354  distally by the trial tip  800  with trial shaft  370  attached, thereby fabricating a stratiform osteochondral graft  1110  with a formed end  1120 , having the cartilage graft material  1100 , that corresponds to the shape of the trial tip distal end  324  of the trial tip  800 . Alternatively, trial tip  800  could be attached to base  330  (of  FIGS.  9 A through  10 B ) to shape cartilage graft material  1100 . The trial timing mark  820  and the delivery tube timing mark  1000  may be maintained in alignment during the compaction process. The delivery tube timing mark  1000  and/or the depth markings  379  of the trial shaft  370  may again be used to ensure that the stratiform osteochondral graft  1110  has the appropriate length to match the length of the tissue tunnel  500 . 
     Compaction may be performed under light force, typically generated by hand pressure, to avoid compromising the biological viability of the cartilage graft material  1100 . The method of compacting the bone graft material under high force (described above in connection with  FIGS.  10 A and  10 B ) as a distinct and separate step from compacting the cartilage graft material under low force is advantageous for fabricating the stratiform osteochondral graft  1110  that has sound structural properties and cohesiveness while preserving the biological viability of the more delicate biological components of the cartilage graft material  1100 . 
     It is advantageous to fabricate a stratiform osteochondral graft  1110  from constituent graft materials for several reason. First, the use autograft or allograft osteochondral plugs can be avoided when desired. The former has risk of harvest site morbidity, and the latter has risk of availability, immunological reactions, and disease transmission. Furthermore, the stratiform osteochondral graft  1110  can be created layer by layer, allowing the selection of the graft material that has the highest potential to remodel and heal into the same tissue constituency and structure as normal osteochondral tissue. For example, normal osteochondral tissue presents with the following distinct biological zones: 1) a cartilage surface layer, where elongate cartilage cells are arranged with their long axes parallel to the surface, 2) a cartilage transition layer, 3) a cartilage deep layer, where elongate cartilage cells are arranged with their long axes perpendicular to the surface, 4) a demarcation layer called the tidemark, 5) a calcified cartilage layer, and 6) a subchondral bone layer. Optimal graft materials can be selected to optimally reproduce the biological constituency and structure of each of these biological layers. A list of graft materials for cartilage and bone is provided below. 
     The bone graft material may be selected from a group consisting of autograft bone, allograft bone, xenograft bone, demineralized bone matrix, bone graft substitutes, extracellular matrix, bone cells, growth factors, blood derivatives, bone marrow aspirate, synthetic bone, and combinations thereof. Bone graft substitutes may be selected from a group consisting of: tricalcium phosphates, hydroxyapatites, calcium phosphates, calcium sulfates, bioglasses, collagen, and combinations thereof. Extra cellular matrix may be selected from a group consisting of proteoglycans (including heparan sulfate, chondroitin sulfate and keratan sulfate), hyaluronic acid, collagen, elastin, fibronectin, laminin. Bone cells may be selected from the group consisting of osteocytes, osteoblasts, mesenchymal stem cells, embryonic stem cells, and combinations thereof. Growth factors may be selected from a group consisting of transforming growth factor (TGF), bone morphogenic protein (BMP), insulin-like growth factor (IGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and combinations thereof. Blood derivatives may be selected from a group consisting of whole blood, platelet rich plasma, and combinations thereof. 
     Cartilage graft material may be selected from a group consisting of autograft cartilage, allograft cartilage, xenograft cartilage, extracellular matrix, tissue scaffolds, cartilage cells, cell sheets, biological glues, growth factors, blood derivatives, bone marrow aspirate, synthetic cartilage, or combinations thereof. Cartilage cells are selected from a group consisting of chondrocytes, chondroblasts, mesenchymal stem cells, embryonic stem cells, and combinations thereof. Biological glues are selected from a group consisting of fibrin glue, mussel glue, vitronectin, chondronectin, osteonectin, fibronectin, laminins, arginine-glycine-aspartic acid peptide, and combinations thereof. 
     Notably, autograft materials may be harvested from other locations in the body, besides the vicinity of the osteochondral lesion  410 . For example, in some embodiments, a second tissue tunnel (not shown) may be formed through the proximal tibia  400  to obtain bone and/or cartilage from a different portion of the proximal tibia  400 . Additionally or alternatively, tissue may be obtained from a different bone and/or joint through the use of the systems and methods set forth above. 
     Once the compaction process of  FIG.  11    has been carried out, the stratiform osteochondral graft  1110  may be ready for placement in the graft site. One manner in which this may be accomplished will be shown and described in connection with  FIGS.  12  and  13   . 
       FIG.  12    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia  400 , showing the delivery tube  350  engaged with the bone port  230 . The stratiform osteochondral graft  1110  may have a graft proximal end  1200  and a graft distal end  1210 . The compacted stratiform osteochondral graft  1110  may be positioned in the delivery tube  350  such that the graft distal end  1210 , with the cartilage graft material  1100 , is oriented toward the graft site. 
       FIG.  13    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia  400 , shown with tamp  240  pushing the graft proximal end  1200  so that the graft distal end  1210  is aligned with the cartilage surface  1300  at the graft site. The stratiform osteochondral graft  1110  may be moved toward the cartilage surface  1300  until the cartilage graft material  1100  is flush with the cartilage surface  1300 . The bone graft  1020  may then occupy the tissue tunnel  500 , proximal to the cartilage surface  1300 , as shown. 
     Once the stratiform osteochondral graft  1110  has been positioned as shown in  FIG.  13   , the tamp  240 , the delivery tube  350 , and the bone port  230  may be removed from the proximal tibia  400 . The wound site may be closed and allowed to heal. The stratiform osteochondral graft  1110  may then integrate with the surrounding tissue. For example, the cartilage graft material  1100  may integrate with the cartilage surface  1300 , and the bone graft  1020  may integrate with the bone surrounding the tissue tunnel  500 . The instruments of the system  300  used in the procedure may be disposed of. The instruments of the system  100  used in the procedure may be re-sterilized and prepared for use in another procedure. 
     In some procedures, defective tissue may be found outside the periphery of the tissue tunnel  500 . In some cases, the ideal retrograde approach may not pass through all of the diseased or damaged tissue that needs to be removed. In other cases, diseased or damaged tissue outside the tissue tunnel  500  may be located (for example, endoscopically) after the tissue tunnel  500  has been formed. Curettes and/or other instruments known in the art may be inserted into the tissue tunnel  500 , through the bone port  230  or directly without the bone port  230 , and used to remove damaged tissue from the walls of the tissue tunnel  500 . Further, in other embodiments, the systems and methods disclosed herein may be used to repair bone defects below an articular surface. In any of the above cases, the damaged tissue may be replaced with any of the materials listed previously. One method for doing this will be shown and described in connection with  FIGS.  14  through  17   . 
       FIG.  14    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia  400  with the bone port  230  secured to the proximal tibia  400  to facilitate access to a tissue tunnel  1400 . An enlarged bone defect site  1410  may be located adjacent to the tissue tunnel  1400 . In  FIG.  14   , the enlarged bone defect site  1410  may be below the articular surface of the proximal tibia  400 ; thus, the tissue tunnel  1400  may be a blind hole through the bone of the proximal tibia  400 , that stops short of the articular cartilage. The tissue tunnel  1400  may be formed, the bone port  230  may be attached, and visualization of the tissue tunnel  1400  may be obtained substantially as set forth previously in the descriptions of  FIGS.  4 - 7   . 
     The funnel  360  may be attached to the bone port  230  to facilitate insertion of a tissue replacement material, such as bone graft material, into the enlarged bone defect site  1410 . In particular, the funnel distal end  364  may be secured to the bone port proximal end  232  such that the funnel longitudinal axis  365  is coaxial with the bone port longitudinal axis  235 . The funnel proximal end  362  may be flared to facilitate insertion of material into the funnel proximal end  362 , and thence into the tissue tunnel  1400  through the funnel  360  and the bone port  230 . Alternatively, a delivery tube  350  (as shown in  FIG.  3   ) may be used between the funnel  360  and the bone port  230 . 
       FIG.  15    is the view of  FIG.  14    showing rotation and pushing of a trial to displace bone graft material  1500  into the enlarged bone defect site  1410 . In this embodiment, the bone graft material  1500  may be a loose and/or uncompacted material. The trial may include the trial shaft  370  and the trial tip  800  with a trial tip distal end  324  that is angled at 45°. 
     The angulation of the trial tip distal end  324  may help the trial tip  800  displace the bone graft material  1500  transverse to the axis of the tissue tunnel  1400 , into the enlarged bone defect site  1410 . Prior to placement of the bone graft material  1500 , the position of the enlarged bone defect site  1410  relative to the tissue tunnel  1400  may be assessed, for example, with medical imaging. The position may be recorded and the trial may be rotated to align the trial tip distal end  324  with the enlarged bone defect site  1410 , for example, by aligning the trial timing marks  820  with the orientation markings  239  of the bone port  230 . The funnel  360  is illustrated in  FIG.  15    but is optional; if desired, the funnel  360  may be omitted to facilitate alignment of the trial timing marks  820  with the orientation markings  239 . 
     After the bone graft material  1500  has been inserted into the enlarged bone defect site  1410 , the bone graft material  1500  may optionally be further pressed into the enlarged bone defect site  1410 . For example, a different selection from the trial tips  320  may be attached to the trial shaft  370  and advanced through the bone port  230  to further press the bone graft material  1500  into the enlarged bone defect site  1410 . Alternatively a tamp  240  (as shown in  FIG.  2   ) can be used. 
       FIG.  16    is the view of  FIG.  15    showing a delivery tube  350  loaded with compacted bone graft material  1600 . The delivery tube  350  may be attached to the bone port  230  as in  FIG.  12   . The compacted bone graft material  1600  may optionally include only bone, rather than being a stratiform graft, as only bone is to be replaced. The compacted bone graft material  1600  may be formed as shown and described in connection with  FIGS.  9 A and  9 B , but may be made with a cylindrical shape rather than having an angled distal surface. Thus, one of the trial tips  320  with a trial tip distal end  324  having a perpendicular orientation and a circular shape may be attached to the base  330  in place of the trial tip  800 , and used in the compaction of the bone graft  1020  to form the compacted bone graft material  1600  with the generally cylindrical shape. 
       FIG.  17    is the view of  FIG.  16    showing tamp  240  pushing the compacted bone graft material  1600  into final position adjacent to the enlarged bone defect site  1410 . The user may rely on the “feel” (i.e., resistance to distal motion) to know when to stop pushing on the handle  247  of the tamp  240 . Additionally or alternatively, medical imaging may be used to assess the location of the enlarged bone defect site  1410  relative to the tissue tunnel  1400 , and the depth markings (i.e., circumferential grooves  249 ) of the tamp  240  may be used to push the bone graft material  1500  to the appropriate depth. Once in place, the compacted bone graft material  1600  may help retain the bone graft material  1500  in place in the enlarged bone defect site  1410 , and may also fill and facilitate healing of the tissue tunnel  1400 . 
     In addition to use of the systems and methods of the present disclosure to address tissue defects, these systems and methods may also be used to fill tissue voids resulting from bone atrophy, other surgical procedures, or prior surgical procedures that did not address the tissue void. One example of this will be presented in connection with  FIGS.  18 - 20   . 
       FIG.  18    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia  400  with obturator  250  inserted through the bone port  230 . The existing tissue tunnel  1800  may be created by the user to facilitate an arthrodesis by placing compacted bone graft material across a joint, or it may be the result of a failed prior surgery, such as a tissue tunnel in a failed anterior cruciate ligament reconstruction surgery. The existing tunnel  1800  may be in the bone only, or may go all the way through the cartilage, like tunnel  500  in  FIG.  7   . The existing tissue tunnel  1800  may be accessed, for example, with the aid of the obturator  250 , the bone port  230  may be attached, and visualization of the existing tissue tunnel  1800  may be obtained substantially as set forth previously in the descriptions of  FIGS.  4 - 7   . The obturator distal end  254  may be bullet shaped to facilitate entry into the existing tissue tunnel  1800 . 
       FIG.  19    is a perspective view from a lateral viewpoint shown in partial cross section of the proximal tibia  400  with the bone port  230  secured to the proximal tibia  400 , the delivery tube  350  attached to the bone port  230 , and the delivery tube loaded with compacted bone graft material  1900 . As in  FIGS.  16  and  17   , the compacted bone graft material  1900  may be formed, for example, as set forth in connection with  FIGS.  9 A and  9 B , and may have a generally cylindrical shape. In alternative embodiments, the compacted bone graft material  1900  may be shaped differently to suit the shape of the portion of the existing tissue tunnel  1800  in which it is to reside. 
       FIG.  20    is the view of  FIG.  19    showing tamp  240  pushing the compacted bone graft material  1900  into final position within the existing tissue tunnel  1800 . The tamp  240  may be used to push the compacted bone graft material  1900  distally until the compacted bone graft  1900  has reached the desired location within the existing tissue tunnel  1800 , which may be a blind end of the existing tissue tunnel  1800  as shown in  FIG.  19   . 
       FIG.  21    is a flow chart showing a method  2100  of treating an osteochondral defect, according to one embodiment. The method  2100  may summarize steps that are shown and described in greater detail in  FIGS.  4  through  13   , and in the accompanying descriptions above. 
     In a step  2110 , a tissue tunnel may be created to circumscribe the osteochondral defect from a retrograde approach. The step  2110  may include the procedures shown in  FIGS.  4  through  7   . 
     In a step  2120 , trialing may be performed to determine the local cartilage and/or bone topography. The step  2120  may include the procedures shown in  FIGS.  8 A and  8 B . 
     In a step  2130 , a stratiform osteochondral graft may be fabricated. The step  2130  may include the procedures shown in  FIGS.  9 A through  11   . 
     In a step  2140 , the stratiform osteochondral graft may be delivered into the tissue tunnel. The step  2140  may include the procedures shown in  FIGS.  12  and  13   . 
       FIG.  22    is a flow chart showing a method  2200  of fabricating a stratiform osteochondral graft, according to one embodiment. The method  2200  may be a more detailed version of the step  2130  of the method  2100 , and may summarize steps that are shown and described in greater detail in  FIGS.  9 A through  11   , and in the accompanying descriptions above. 
     In a step  2210 , bone graft material may be compacted so that the distal end of the bone graft material closely matches the local cartilage and/or bone topography. The step  2210  may include the procedures shown in  FIGS.  9 A through  10 B . 
     In a step  2220 , cartilage graft material may be compacted so that the distal end of the cartilage graft material closely matches the local cartilage and/or bone topography. The step  2220  may include the procedures shown in  FIG.  11   . 
       FIG.  23    is a flow chart showing a method  2300  of treating a bone defect, according to one embodiment. The method  2300  may summarize steps that are shown and described in greater detail in  FIGS.  14  through  17   , and in the accompanying descriptions above. Steps from  FIGS.  9 A through  10 B  may also be included. 
     In a step  2310 , a bone tunnel may be created to access a bone defect. The step  2310  may include the procedures shown in  FIG.  14   . 
     In a step  2320 , a bone defect Space adjacent to the bone tunnel may be filled with bone graft material. The step  2320  may include the procedures shown in  FIGS.  15  and  16   . 
     In a step  2330 , bone graft material may be compacted, or a bone graft plug may be otherwise obtained. The step  2330  may include the procedures shown in  FIGS.  9 A through  10 B . 
     In a step  2340 , the compacted bone graft material or the bone graft plug may be delivered to the bone tunnel. The step  2340  may include the procedures shown in  FIG.  17   . 
       FIG.  24    is a flow chart showing a method  2400  of treating an existing bone tunnel, according to one embodiment. The method  2400  may summarize steps that are shown and described in greater detail in  FIGS.  18  through  20   , and in the accompanying descriptions above. Steps from  FIGS.  9 A through  10 B  may also be included. 
     In a step  2410 , an existing bone tunnel may be located with an obturator and a bone port. The step  2410  may include the procedures shown in  FIG.  18   . 
     In a step  2420 , bone graft material may be compacted, or a bone graft plug may be otherwise obtained. The step  2420  may include the procedures shown in  FIGS.  9 A through  10 B . 
     In a step  2430 , the compacted bone graft material or the bone graft plug may be delivered to the bone tunnel. The step  2430  may include the procedures shown in  FIGS.  19  and  20   . 
     The method  2100 , the method  2200 , the method  2300 , and the method  2400  may utilize the system  100 , the subset  200 , and/or the system  300 . In the alternative, the method  2100 , the method  2200 , the method  2300 , and the method  2400  may employ differently configured instruments. Likewise, the system  100 , the subset  200 , and/or the system  300  may be utilized in methods different from the method  2100 , the method  2200 , the method  2300 , and the method  2400 . Further, steps may be added to, omitted from, and/or replaced with alternatives in any of the method  2100 , the method  2200 , the method  2300 , and the method  2400 , as would be envisioned by a person skilled in the art. 
     Reference throughout this specification to “an embodiment” or “the embodiment” means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the quoted phrases, or variations thereof, as recited throughout this specification are not necessarily all referring to the same embodiment. 
     Similarly, it should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the present disclosure. This method of disclosure, however, is not to be interpreted as reflecting an intention that any embodiment requires more features than those expressly recited in that embodiment. Rather, inventive aspects lie in a combination of fewer than all features of any single foregoing disclosed embodiment. 
     As used herein, the term “proximal” means a location relatively closer to a user (i.e., a surgeon) when the user is installing the implant. The term “distal” means a location relatively further from the user. For example, when a user installs a bone screw into a material with a driver, the end of the bone screw engaged with the driver is the proximal end, and the tip of the bone screw that first engages the material is the distal end. The term “cannulated” means having a central bore extending along a longitudinal axis of a part between a proximal end and a distal end of the part. 
     Recitation of the term “first” with respect to a feature or element does not necessarily imply the existence of a second or additional such feature or element. Elements recited in means-plus-function format are intended to be construed in accordance with 35 U.S.C. § 112(f). It will be apparent to those having skill in the art that changes may be made to the details of the above-described embodiments without departing from the underlying principles set forth herein. 
     The phrases “connected to,” “coupled to” and “in communication with” refer to any form of interaction between two or more entities, including mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interaction. Two components may be functionally coupled to each other even though they are not in direct contact with each other. The term “coupled” can include components that are coupled to each other via integral formation, as well as components that are removably and/or non-removably coupled with each other. The term “abutting” refers to items that may be in direct physical contact with each other, although the items may not necessarily be attached together. The phrase “fluid communication” refers to two or more features that are connected such that a fluid within one feature is able to pass into another feature. As defined herein the term “substantially” means within +/−20% of a target value, measurement, or desired characteristic. 
     While specific embodiments and applications of the present disclosure have been illustrated and described, it is to be understood that the scope of this disclosure is not limited to the precise configuration and components disclosed herein. Various modifications, changes, and variations which will be apparent to those skilled in the art may be made in the arrangement, operation, and details of the devices, systems, and methods disclosed herein.