Abstract:
The invention is directed toward a surgical kit having component parts capable of use in excising a cartilage defect site on a patient to prepare the same for receipt of an implant plug, the kit comprising a cylindrical gauge with a central bore used to measure the defect area, a guide rod adapted to be driven through the gauge tube into the center of said defect area and a cartilage cutting assembly adapted to be mounted over the guide rod and used for excising the defect area and cutting a cylindrical bore into the defect area. The method for use of the kit comprises the steps of: marking the defect area to be cut; placing a guide rod into the center defect area and driving the same to a predetermined distance to secure the same in the defect area and placing a drill bit over the guide rod and rotating the drill bit to cut a cylindrical blind bore removing the cartilage defect.

Description:
RELATED APPLICATIONS 
       [0001]    The present application is related to and claims priority from U.S. Provisional Patent Application No. 61/129,028 filed May 30, 2008. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       REFERENCE TO SEQUENCE LISTING, A TABLE OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX 
       [0003]    None. 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of Invention 
         [0005]    The present invention is generally directed toward the surgical treatment of articular chondral defects and is more specifically directed toward a surgical cutting assembly for removing the cartilage defect from the patient by drilling a blind bore in the defect area ranging from 10 to 40 mm in diameter to excise the defect area allowing a cylindrical allograft cartilage implant plug to be accurately orientated and placed in the blind bore. 
         [0006]    2. Description of the Prior Art 
         [0007]    Articular cartilage injury and degeneration present medical problems to the general population which are constantly addressed by orthopedic surgeons. Every year in the United States, over 500,000 arthroplastic or joint repair procedures are performed. These include approximately 125,000 total hip and 150,000 total knee arthroplastics and over 41,000 open arthroscopic procedures to repair cartilaginous defects of the knee. 
         [0008]    In the knee joint, the articular cartilage tissue forms a lining which faces the joint cavity on one side and is linked to the subchondral bone plate by a narrow layer of calcified cartilage tissue on the other. Articular cartilage (hyaline cartilage) consists primarily of an extracellular matrix with a sparse population of chondrocytes distributed throughout the tissue. Articular cartilage is composed of chondrocytes, type II collagen fibril meshwork, proteoglycans and water. Active chondrocytes are unique in that they have a relatively low turnover rate and are sparsely distributed within the surrounding matrix. The collagens give the tissue its form and tensile strength and the interaction of proteoglycans with water give the tissue its stiffness to compression, resilience and durability. The hyaline cartilage provides a low friction bearing surface over the bony parts of the joint. If the cartilage lining becomes worn or damaged resulting in lesions, joint movement may be painful or severely restricted. Whereas damaged bone typically can regenerate successfully, hyaline cartilage regeneration is quite limited because of it&#39;s limited regenerative and reparative abilities. 
         [0009]    Articular cartilage lesions generally do not heal, or heal only partially under certain biological conditions due to the lack of nerves, blood vessels and a lymphatic system. The limited reparative capabilities of hyaline cartilage usually results in the generation of repair tissue that lacks the structure and biomechanical properties of normal cartilage. Generally, the healing of the defect results in a fibrocartilaginous repair tissue that lacks the structure and biomedical properties of hyaline cartilage and degrades over the course of time. Articular cartilage lesions are frequently associated with disability and with symptoms such as joint pain, locking phenomena and reduced or disturbed function. These lesions are difficult to treat because of the distinctive structure and function of hyaline cartilage. Such lesions are believed to progress to severe forms of osteoarthritis. Osteoarthritis is the leading cause of disability and impairment in middle-aged and older individuals, entailing significant economic, social and psychological costs. Each year, osteoarthritis accounts for as many as 39 million physician visits and more than 500,000 hospitalizations. By the year 2020, arthritis is expected to affect almost 60 million persons in the United States and to limit the activity of 11.6 million persons. Patient or recipient repair sites are normally present in the weight bearing area of the medial and lateral femoral condyles. 
         [0010]    There are many current therapeutic methods being used. None of these therapies has resulted in the successful regeneration of hyaline-like tissue that withstands normal joint loading and activity over prolonged periods. Currently, the techniques most widely utilized clinically for cartilage defects and degeneration are not articular cartilage substitution procedures, but rather lavage, arthroscopic debridement, and repair stimulation. The direct transplantation of cells or tissue into a defect and the replacement of the defect with biologic or synthetic substitutions presently accounts for only a small percentage of surgical interventions. The optimum surgical goal is to replace the defects with cartilage-like substitutes so as to provide pain relief, reduce effusions and inflammation, restore function, reduce disability and postpone or alleviate the need for prosthetic replacement. 
         [0011]    Lavage and arthroscopic debridement involve irrigation of the joint with solutions of sodium chloride, Ringer or Ringer and lactate. The temporary pain relief is believed to result from removing degenerative cartilage debris, proteolytic enzymes and inflammatory mediators. These techniques provide temporary pain relief, but have little or no potential for further healing. 
         [0012]    Repair stimulation is conducted by means of drilling, abrasion arthroplasty or microfracture. Penetration into the subchondral bone induces bleeding and fibrin clot formation which promotes initial repair, however, the tissue formed is fibrous in nature and not durable. Pain relief is temporary as the tissue exhibits degeneration, loss of resilience, stiffness and wear characteristics over time. 
         [0013]    The periosteum and perichondrium have been shown to contain mesenchymal progenitor cells capable of differentiation and proliferation. They have been used as grafts in both animal and human models to repair articular defects. Few patients over 40 years of age have obtained good clinical results, which most likely reflects the decreasing population of osteochondral progenitor cells with increasing age. There have also been problems with adhesion and stability of the grafts, which result in their displacement or loss from the repair site. 
         [0014]    Transplantation of cells grown in culture provides another method of introducing a new cell population into chondral and osteochondral defects. Carticel® is a commercial process to culture a patient&#39;s own cartilage cells for use in the repair of cartilage defects in the femoral condyle and is marketed by Genzyme Biosurgery in the United States and Europe. The procedure uses arthroscopy to take a biopsy from a healthy, less loaded area of articular cartilage. Enzymatic digestion of the harvested tissue releases the cells that are sent to a laboratory where they are grown for a period ranging from 2-5 weeks. Once cultivated, the cells are injected during a more open and extensive knee procedure into areas of defective cartilage where it is hoped that they will facilitate the repair of damaged tissue. An autologous periosteal flap with cambium layer is sutured around the defect and is used to seal the transplanted cells in place and act as a mechanical barrier. Fibrin glue is used to seal the edges of the flap. This technique preserves the subchondral bone plate and has reported a high success rate. Proponents of this procedure report that it produces satisfactory results, including the ability to return to demanding physical activities, in more than 90% of patients and that biopsy specimens of the tissue in the graft sites show hyaline-like cartilage repair. More work is needed to assess the function and durability of the new tissue and determine whether it improves joint function and delays or prevents joint degeneration. As with the perichondrial graft, patient/donor age may compromise the success of this procedure as chondrocyte population decreases with increasing age. Disadvantages to this procedure include the need for two separate surgical procedures, potential damage to surrounding cartilage when the periosteal patch is sutured in place, the requirement of demanding microsurgical techniques, and the expensive cost of the procedure which is currently not covered by insurance. 
         [0015]    Osteochondral transplantation or mosaicplasty involves excising all injured or unstable tissue from the articular defect and creating cylindrical holes in the base of the defect and underlying bone. These holes are filled with autologous cylindrical plugs of healthy cartilage and bone in a mosaic fashion. The autologous osteochondral plugs are harvested from a lower weight-bearing area of lesser importance in the same joint. Reports of results of osteochondral plug autografts in a small numbers of patients indicate that they decrease pain and improve joint function, however, long-term results have not been reported. Factors that can compromise the results include donor site morbidity, effects of joint incongruity on the opposing surface of the donor site, damage to the chondrocytes at the articular margins of the donor and recipient sites during preparation and implantation, and collapse or settling of the graft over time. The limited availability of sites for harvest of osteochondral autografts restricts the use of this approach to treatment of relatively small articular defects and the healing of the chondral portion of the autograft to the adjacent articular cartilage remains a concern. 
         [0016]    Transplantation of large allografts of bone and overlying articular cartilage is another treatment option that involves a greater area than is suitable for autologous cylindrical plugs, as well as for a non-contained defect. The advantages of osteochondral allografts are the potential to restore the anatomic contour of the joint, lack of morbidity related to graft harvesting, greater availability than autografts and the ability to prepare allografts in any size to reconstruct large defects. Clinical experience with fresh and frozen osteochondral allografts shows that these grafts can decrease joint pain, and that the osseous portion of an allograft can heal to the host bone and the chondral portion can function as an articular surface. Drawbacks associated with this methodology in the clinical situation include the scarcity of fresh donor material and problems connected with the handling and storage of frozen tissue. Fresh allografts also carry the risk of immune response or disease transmission. Musculoskeletal Transplant Foundation (MTF) has preserved fresh allografts in a media that maintains a cell viability of 50% for 35 days for use as implants. Frozen allografts lack cell viability and have shown a decreased amount of proteoglycan content which contribute to deterioration of the tissue. 
         [0017]    A number of United States patents have been specifically directed towards the manufacture of plugs or cores which are implanted into a cartilage defect. U.S. Pat. No. 6,591,581 issued Jul. 15, 2003 describes a precut bone plug for use in allograft core transplantation surgery which has a tissue bank harvest the graft using a coring trephine with teeth having an inner diameter between 0.5 mm to 0.1 to create a bone core with a hyaline cartilage layer in approximately 7.9 mm, 9.9 mm, 11.9 mm diameters. A donor cutting harvester having a cutter tube with a straight cutting edge, a window slot and depth markings with a torque handle on the proximal end may be used to obtain an autograft core as is shown in U.S. Pat. No. 5,919,196 issued Jul. 6, 1999. This same reference also discloses a punch cutter which is cannular. As noted in U.S. Pat. No. 6,591,581 issued Jul. 15, 2003 an allograft osteochondral transplantation method is known, in which a surgeon is provided with a whole cadaver knee from a tissue bank along with an instrument set containing the full range of sizers and sized instruments. In this allograft method, the surgeon must determine the size for the graft needed and then perform the surgery. The &#39;581 patent notes that this method is undesirable due to several factors including the preoperative preparation required for the surgeon to harvest and prepare the donor core, the waste from discarding each cadaver knee after the one operation without realizing the full potential for each knee to yield multiple allograft cores and the comprehensive instrumentation system which must be sent to and recovered from the operation site. This patent discloses instruments for cutting a bone core by cutting or punching having collared pins disposed within the harvester for removal of the harvester cores. U.S. Pat. No. 6,592,588 issued Jul. 15, 2003 discloses apparatus for allograft transplantation of articular cartilage with bone from one site to another to treat chondral defects. The &#39;588 patent discloses a handle having a cylindrical bar extending through it transverse to the axis of the cutting tube mounted to the handle. The cutting tube is provided with a longitudinal slot which allows view of the depth of the penetration of the cutting tube. 
         [0018]    U.S. Pat. Nos. 6,488,033 and 6,852,114 (a divisional application of the &#39;033 patent) issued respectively Dec. 3, 2002 and Feb. 8, 2005 are directed toward an osteochondral transplant workstation for cutting a core out of an allograft bone held in an adjustable vise with a lubricated rotary cutting bit. The core is removed from the bit, held in a specially designed set of pliers, and cut to size by a saw blade to fit into a blind bore which has been oriented and drilled into the patient&#39;s arthritic defect area. This workstation while an improvement over existing procedures is cumbersome to use and requires experience and training. 
         [0019]    The present invention was designed to overcome prior art procedures and provide a simple to use bore cutting assembly which accurately excises the patient&#39;s bone defect area to form a clean cut bore in the patient for receipt of the core shaped implant. 
       SUMMARY OF THE INVENTION 
       [0020]    A surgical kit having component parts capable of use in excising a cartilage defect site in a patient to prepare the same for receipt of an implant plug, the kit comprising; a sizing gauge used to accurately measure the defect area, the gauge defining a bore which holds and guides a guide drill rod. The guide drill rod is adapted to be driven into the center of said defect area and extend therefrom and a cartilage cutting assembly is adapted to be mounted over the guide drill rod. The cartilage cutting assembly comprises a drill bit with a cannula adapted to be mounted over the guide drill rod for excising the defect area and cutting a cylindrical bore into a patients condyle. 
         [0021]    The method for use of the cutting assembly comprises the steps of: a) marking the defect area to be cut with a sizer gauge; b) placing a guide rod into the sizer gauge and driving the guide rod in the defect area a predetermined distance to secure the guide rod in the defect area; c) inserting a cutter assembly over the guide rod onto the defect area and cutting the cartilage around the defect area and cutting a cylindrical blind bore removing the defect area. 
         [0022]    It is an object of the invention to provide a surgical kit for forming a cleanly cut bore with a sharply cut cartilage layer of the correct diameter size for the insertion of an allograft plug to repair a cartilage defect. 
         [0023]    It is also an object of the invention to provide a surgical kit allowing the excision of the defect area for cartilage repair. 
         [0024]    It is yet another object of the invention to provide a surgical kit having a cutter which scores the cartilage area prior to cutting and excising the cartilage defect site. 
         [0025]    It is still another object of the invention to provide a surgical kit which marks and defines the defect area to be excised. 
         [0026]    It is further an object of the invention to provide a surgical kit which can be easily used by the surgeon to create a correctly dimensioned blind bore. 
         [0027]    It is yet another object of the invention to provide a surgical kit which can be easily cleaned and sterilized with disposable parts which can be discarded after the one use. 
         [0028]    It is still another object of the invention to provide a kit to allow accurate bore diameter selections and depths. 
         [0029]    It is a further object of the invention to provide a surgical kit which allows the cartilage layer to be removed without cracking or breaking the surrounding remaining cartilage layer. 
         [0030]    These and other objects, advantages, and novel features of the present invention will become apparent when considered with the teachings contained in the detailed disclosure along with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]      FIG. 1  is an exploded perspective view of the inventive cartilage defect cutting assembly; 
           [0032]      FIG. 2  is a perspective view of the lesion gauge shown in  FIG. 1 ; 
           [0033]      FIG. 3  is an enlarged side elevation view of the lesion gauge shown in  FIG. 2 ; 
           [0034]      FIG. 4  is a top plan view of the lesion gauge shown in  FIG. 3 ; 
           [0035]      FIG. 5  is a bottom plan view of the lesion gauge shown in  FIG. 3 ; 
           [0036]      FIG. 6  is a cross section of  FIG. 3  taken along line  6 ′- 6 ′; 
           [0037]      FIG. 7  is an enlarged exploded side view of the guide rod shown in  FIG. 1 ; 
           [0038]      FIG. 8  is an enlarged perspective view of the cannular cutting reamer shown in  FIG. 1 ; 
           [0039]      FIG. 9  is a reduced side view of the cannular cutting reamer shown in  FIG. 8 ; 
           [0040]      FIG. 10  is a front view of the cannular cutting reamer shown in  FIG. 9 ; 
           [0041]      FIG. 11  is a rear elevational view of the cannular cutting reamer shown in  FIG. 9 ; 
           [0042]      FIG. 12  is a cross sectional view of  FIG. 10  taken along line  12 ′- 12 ′; 
           [0043]      FIG. 13  is a perspective view showing the marked area around the defect and the guide rod extending from the defect area of the condyle; 
           [0044]      FIG. 14  is an enlarged perspective view of a cannular cutting reamer shown in  FIG. 1  mounted on the guide rod for boring; 
           [0045]      FIG. 15  is a perspective view of the medial condyle surface with the blind bore cut through the cartilage layer and cortical bone layer into the cancellous bone of the defect site forming a prepared recipient site; 
           [0046]      FIG. 16  is an exploded perspective view of an alternative embodiment of the cartilage defect cutting assembly; 
           [0047]      FIG. 17  is an enlarged perspective view of the sizing tube shown in  FIG. 16 ; 
           [0048]      FIG. 18  is a partial view of the distal end of the sizing tube shown in  FIG. 17  placed on a condyle with a defect; 
           [0049]      FIG. 19  is an end view of the sizing tube shown in  FIG. 17  looking down on the defect area; 
           [0050]      FIG. 20  is an enlarged perspective view of the drill centering guide member shown in  FIG. 16  placed in the sizing tube with the drill guide rod located at the center of the defect; 
           [0051]      FIG. 21  is a perspective view of the drill guide rod in the condyle with the sizer and drill centering guide member removed; 
           [0052]      FIG. 22  is an enlarged perspective view of a punch cutter shown in  FIG. 16  which can used for cutting the defect area of the cartilage on the condyle; 
           [0053]      FIG. 23  is an enlarged perspective view of the T shaped removable drive handle shown in  FIG. 16 ; and 
           [0054]      FIG. 24  is a perspective view of the T shaped drive handle of  FIG. 23  with a mounted punch cutter of  FIG. 22  mounted on the drill guide rod. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0055]    The term “tissue” is used in the general sense herein to mean any transplantable or implantable tissue such as bone. 
         [0056]    The terms “transplant” and “implant” are used interchangeably to refer to tissue (xenogeneic or allogeneic) which may be introduced into the body of a patient to replace or supplement the structure or function of the endogenous tissue. 
         [0057]    The terms “autologous” and “autograft” refer to tissue or cells which originate with or are derived from the recipient, whereas the terms “allogeneic” and “allograft” refer to tissue which originate with or are derived from a donor of the same species as the recipient. The terms “xenogeneic” and “xenograft” refer to tissue which originates with or are derived from a species other than that of the recipient. 
         [0058]    The present invention is directed towards a cartilage cutting kit or assembly  20  as seen in  FIG. 1  for cutting a circular area to remove a cartilage defect  200 . The preferred embodiment and best mode of the invention is shown in  FIGS. 1-14 . 
         [0059]    In the preferred embodiment of the cartilage cutting kit  20 , a cartilage lesion gauge  30  is used to mark the area around the defect area  200  and orient the drill rod  50  so that it can be driven into the defect area. The lesion gauge  30  as best seen in  FIGS. 2-6  is placed over the cartilage defect area  200  so that the defect area is covered. It will be appreciated that the gauge is substantially cylindrical and can have different sized diameters ranging from 10, 15, 18, 20, 22, 25, 30 and 35 mm. Furthermore each kit comes with a number of different sized (diameter) gauges to allow the covering of cartilage defect areas of different sizes. The gauge body  32  has a solid one piece construction with cylindrical distal or front section  34 , a tapered or conical middle section  35  and a larger diameter proximal or rear section  36 . The material forming the body is preferably color coded in different colors representing the different diameters of the gauge body  32 . The distal end section  34  of the gauge body  32  is formed with extending tripod legs  38  and a linear sighting channel  40  cut in the exterior surface of the body runs from the proximal end of the body to the bottom of each leg  38  to form a sighting line for the surgeon as can be seen in  FIG. 3 . A throughgoing bore  42  is cut through the center of the body  32  to receive a guide drill rod  50 . The bore  42  widens at its proximal end in a funnel or cone shape  44  with a chamfered edge  46  which allows easy insertion of the guide drill rod  50  during surgery. The distal end of bore  42  communicates with a cup shaped recess  43  cut into the distal end of the body section  34 . 
         [0060]    An appropriate sized body (diameter)  32  is selected and placed in a three point stance on the condyle cartilage surface  201  surrounding the defect area  200  and alignment marks  300  are drawn on the cartilage surface  201  around the patients cartilage defect area  200 . The tripod leg structure of the body offers greater stability on the slippery condyle cartilage surface. The orientation of the tripod legs assure correlation of alignment of the allograft core to the patient&#39;s defect bore. The surgeon selects an appropriately sized gauge to cover the lesion which also determines the size of the reamer bit. It will be appreciated that a number of reamer bits having corresponding diameters to those of the lesion gauges are also provided in the kit. The patients defect site is marked at 12 o&#39;clock and at approximately 4 and 8 o&#39;clock if the surgeon so chooses. The 12 o&#39;clock position is critical. The same marking are placed on the osteochrondal core created from the allograft. Once the defect site  200  has been sized by the lesion gauge  30 , a guide rod  50  is drilled through the cannulated lesion gauge  30  to maintain a point of reference allowing the guide rod  50  to be positioned perpendicular to the defect  200 . 
         [0061]    The guide rod  50  as seen in  FIG. 7  is constructed with a shaft  52  having a drill screw tip  54  at its distal end and a smooth surface  56  with a chamfer  58  or chuck at its proximal end. Drill depth markings  60  are provided on the shaft  52  to allow visualization of the drill depth. Once the guide drill rod  50  is driven into the defect area  200  and the lesion gauge  30  is removed the drill rod  50  extends outward from the defect area  200 . 
         [0062]    The lesion gauge  30  is slid off the guide rod  50  and a reamer bit  90  is placed over the guide rod  30  for removal of the defect and creation of the blind bore. The reamer bit  90  is designed so that its cutting blades score the cartilage surface first and then cut through the cartilage and subchrondal bone. 
         [0063]    The reamer cutting or boring bit  90  has a cannular shaft  92  with a cutting blade  94  as seen in  FIGS. 8 ,  9  and  12  and a stepped chuck  93  with a Hudson quick disconnect  97  on the proximal end. The cutting blade  94  has a sharp leading edge  95  to initially score the cartilage and keep the cartilage from chipping during the initial cartilage cutting and has a second edge for cutting the bone and defines two angled channels  96  to direct the cut cartilage and bone shard materials upward through the bit and outside of the bore. The reamer bit  90  is marked with laser bore depth markings  98  so that the depth of the bore  230  can be easily and accurately determined. The cutting blade  94  is driven by a standard drill and the cutting action results in a clean blind bore  230  cut into the patient as seen in  FIG. 15 . The reamer bit  90  is removed from the guide rod  50 . A depth gauge (not shown) is placed on the guide rod  50  and slid into the bore to measure the depth of the blind bore  230  at the three locations of 12, 4 and 8 o&#39;clock as previously noted. The depth gauge is removed from the guide rod  50  and a dilator is placed over the guide rod  50  and driven into the blind bore  230  to slightly expand same prior to insertion of the osteochrondral plug. 
         [0064]    An alternative embodiment of the cartilage cutting assembly  120  is seen in  FIG. 16 . In this embodiment a sizing tube  130  as seen in  FIGS. 17 and 18  is used to measure the defect area  200 . The sizing tube  130  is a cylindrical body  132  made of transparent plastic for maximum visualization of the defect or of anodized aluminum which is color coded for quick size matching. It will be appreciated that different diameter sizing tubes can be use depending upon the area of the defect to be excised and sizes of 10, 15, 18, 20, 22, 25, 30 and 35 mm in diameter can be used. The distal end of the cylindrical sizing tube body  132  is formed with extending tri-pod legs or feet  134  with a sighting channel  136  running from the proximal end of the tube to the bottom of each foot  134  to form a sighting line for the surgeon. The sighting line  136  widens at  137  in each foot  134  to provide a marking pen slot  138  and a throughgoing aperture  139  is located at the distal end of the sizing tube and above the base of each foot  134  to provide a marking pen aperture and visualization port for viewing the defect area  200 . 
         [0065]    A cannular guide rod centering tube  140  is then inserted in the sizing tube  130 . As seen in  FIG. 20 , the guide rod centering tube  140  has been inserted into the sizing tube  130  for placement of the drill guide rod  50 . The guide rod centering tube  140  is constructed with a metal cylindrical body  142  having an internally threaded cap  144  mounted over its proximal end, the cap  144  defining a centrally positioned aperture  145  which is sized to receive the guide drill rod  50 . A planar end piece  146  as shown in phantom on  FIG. 20  is mounted to the distal end of the cylindrical body  142 , the end piece  146  also defining a centrally positioned aperture (not shown) which is axially aligned with aperture  145 . If desired, a centrally positioned tube having an internal diameter which is greater than the outer diameter of the guide drill rod  50  can be concentrically mounted inside cylindrical body  142  to receive the guide drill rod  50 . 
         [0066]    The guide rod centering tube  140  and sizing tube  130  are then removed from the guide drill rod  50  and a punch cutter  160  is threadably mounted to a cannular T-handle assembly  170 . The punch cutter  160  shown in  FIG. 22  has a cylindrical body  162  with a threaded collar  164  on the proximal end and a sharpened inwardly beveled distal cutting edge  165 . A drill centering guide  166  is mounted inside the cylindrical body  162  and has a cylindrical outer body  167  with inwardly projecting arms or spokes  168  terminating in a circular hub  169  which serves as a drill centering guide when it is mounted over the guide drill rod  50 . The punch cutter  160  is constructed of stainless steel and the drill centering guide  166  is preferably made of molded plastic with the total punch cutter  160  being a single use disposable item. The T-handle assembly  170  for the punch cutter is best seen in  FIGS. 23 and 24  is constructed with interchangeable tubular shafts  172 , the distal end  173  being secured to a threaded stepped collar  174  which receives the threaded collar  164  of the punch cutter  160  on its lower threaded section  175 . The proximal end of shaft  172  has a quick release socket  176  which holds the removable handle  178  on the shaft. The handle  178  has a circular impact surface  179  with the top of the hammering surface being planar with a tubular section  180  which fits over the quick release socket  176 . Arms  182  extend outward from the circular impact surface  179 . The arms  182  are of a width and have curved ends  184 . The top surface  186  and bottom surface  188  of the arms both have a curved surface which allows the same to be easily grasped by the user. If desired a punch cutter  160  and T-handle assembly  170  are mounted on the guide drill rod  50  as seen in  FIG. 24  and the recipient punch cutter  160  is driven in by hand (straight and/or rotated) or hammered into the cartilage surface  201  of the patients condyle to cut a clean bore diameter in the patient recipient. 
         [0067]    The T-handle assembly  170  and associated punch cutter  160  are removed from the drill rod  50  and the cannular boring bit  90  is mounted on the guide drill rod  50  against the scored area  202  of defect  200 . 
         [0068]    In operation, the lesion or defect is removed by cutting a blind bore  230  in a patient&#39;s bone of a predetermined diameter and depth in the defect area with a cannular boring bit  90 . A lesion gauge  30  or sizing tube  130  is used to measure the extent of the defect  200  so that the defect is contained within the inner diameter of the lesion gauge  30  or sizing tube  130  and the cartilage defect area is marked  300  with a pen or other marking device to determine the orientation of the bore. When the alternate embodiment of  FIG. 16  is used a drill rod centering guide  140  is inserted in the sizing tube  130 . 
         [0069]    The guide drill rod  50  is placed in the drill centering guide  140  or the bore  42  of the lesion gauge  30  against the defect  200  so that it is in the center of the defect area  200 . Once the guide drill rod  50  is driven into the defect area and secured in the bone of the defect area, either the lesion gauge  30  or the sizing tube  130  and drill centering guide tube  140  are removed from the guide drill rod  50  leaving the guide drill rod  50  extending upward from the defect area  200 . When the alternate embodiment of  FIG. 16  is used a punch cutter  160  is threadably mounted to a cannular T-handle assembly  170  and mounted over the drill rod  50  so that the drill rod extends through the punch cutter hub  169  into the cannula of the T-handle assembly  50 . The T-handle assembly  170  is driven with a hammer or other driving means so that the cartilage surface  201  of the defect area  200  is cut by the punch cutter leaving a clean cartilage cut without cracking or shattering. The associated punch cutter  160 , blade  165  and T-handle assembly  170  is removed from the guide drill rod  50 . With either embodiment the cannular reamer bit  90  which is selected in size to correspond to the diameter of the lesion gauge  30  or sizing tube  130  is mounted on the guide drill rod  50  and cuts out the defect area so that the rotating blade  94  cuts a blind bore  230  in the femur to remove the condyle defect  210  and associated cartilage  201  and bone  204 . The result is a cleanly cut bore  230  as seen in  FIG. 15  which is set to receive the cylindrical core of the allograft cartilage implant (not shown) 
         [0070]    The length of the osteochondral plug implant can be the same as the depth of the bore  230  or less than the depth of the bore If the plug is the same length, the base of the plug implant is supported and the articular cartilage cap is level with the articular cartilage of the patients bone surface. If the plug is of a lesser length, the base of the plug implant is not supported but support is provided by the wall of the bore or respective cut out area as the plug is interference fit within the bore or cut out area with the cap being flush with the articular cartilage depending on the surgeon&#39;s preference. With such load bearing support the graft surface is not damaged by weight or bearing loads which can cause micromotion interfering with the graft interface producing fibrous tissue interfaces and subchondral cysts. 
         [0071]    The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. However, the invention should not be construed as limited to the particular embodiments which have been described above. Instead, the embodiments described here should be regarded as illustrative rather than restrictive. Variations and changes may be made by others without departing from the scope of the present invention as defined by the following claims: