Abstract:
A device and technique for the preparation and implantation of osteochondral allografts for resurfacing of a human joint. The grafts are prepared to a uniform shell thickness using the described invention.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 61/028,153, filed Feb. 12, 2008. 
     
    
     SEQUENCE LISTING 
       [0002]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0003]    Not applicable. 
       THE NAMES OR PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0004]    Not applicable. 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
       [0005]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0006]    1. Field of the Invention 
         [0007]    The present invention relates generally to methods and apparatus for orthopedic joint repair and reconstruction, and more particularly to a novel set of surgical instruments and a method of using the same for the preparation and implantation of osteochondral allografts for resurfacing of the hip joint, knee joint, and shoulder joint. The grafts are prepared to a uniform shape and peripheral topography to the topography of the recipient site. 
         [0008]    2. Discussion of Related Art Including Information Disclosed Under 37 CFR §§1.97, 1.98 
         [0009]    Reconstruction of joints remains an ongoing area of investigation. Since the work of Erich Lexer in the early part of the twentieth century, entire joints have been transplanted into human patients. These large grafts termed “allografts” were associated with high failure rates and cartilage degeneration. Additionally, the transplant recipient was required to immobilize the joint and to avoid bearing weight on the transplant for long periods of time. 
         [0010]    In the early 1970&#39;s, the concept of shell allografts consisting of fresh bone and cartilage was introduced. With these grafts, only a thin shell of bone was transplanted. The thin bone shell essentially functioned as a carrying vehicle for the fresh articular cartilage that would remain populated with cells from the donor. Once the bone of the host healed to the graft bone, the articular cartilage would continue to receive nutrition from the synovial fluid in the joint. The bone, due to its small volume, generated a minimal immune response. Using this technique, large areas of articular cartilage could be repaired with normal cartilage with no need for systemic immunosuppressive medications. The success of this surgical procedure is well documented and is based on both clinical improvements as well as documented long-term donor cell viability (nearly 30 years after the transplantation). 
         [0011]    Tissue engineering can be defined as a multidisciplinary field applying the principles of engineering and biological sciences with the goal of regeneration and/or restoration of tissues and organs. Up to the present time the major areas of clinical application of tissue engineering in orthopaedic surgery have been in autologous chondrocyte implantation, in which cells from a donor cartilage are pre-harvested, cultured, and then injected into the recipient under a periosteal or synthetic patch with the aim of forming mature hyaline-like cartilage. The principal efforts in this field are now being directed at manufacturing complete tissues that include both cartilaginous and osseous components of the joint surface in order to optimize healing of the artificial tissue to the recipient bone. However, to date no osteochondral tissue engineered constructs for cartilage repair have been widely used in humans. Were such an implant to be developed, a method will be required to prepare the recipient site precisely based on its surface characteristics so as to accommodate the implant with a flush joint surface. 
         [0012]    In the area of osteochondral allograft instrumentation, the emphasis has been on cylindrical instrumentation to prepare cores that can be trimmed and transplanted into cylindrically prepared recipient sites in the complementary portion of the joint. In U.S. Pat. No. 6,488,033, to Cerundolo, there is described a method of obtaining and placing an osteochondral allograft in substantially the same orientation as the damaged segment of the bone which is initially removed from the patient. With this technique, the surface of the transplanted plug is matched to the contour of the excised osteochondral tissue. However, the placement of the guides is essentially dependent on free hand techniques and the guides do not provide a precise match with the complex contours of the cartilaginous surface. 
         [0013]    U.S. Pat. No. 6,591,581, to Schmieding, teaches a method and instrumentation for the preparation, distribution, and insertion of round, size specific osteochondral allografts. The distribution network for fresh osteochondral allograft cores is laid out, along with some details for instrumentation in preparing such osteochondral plugs and recipient sites. This instrumentation is analogous to that discussed in U.S. Pat. No. 5,919,196, to Bobic et al, for autologous osteochondral transfer, otherwise known as mosaicplasty. However, no insights are offered by these publications into meeting the challenges of preparing a perfect surface match for these large osteochondral cylindrical grafts. 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    The present invention relates to a specialized device for the preparation of large cylindrical grafts up to 40 mm in diameter with precise surface matching of the donor and recipient. The perfect matching is due to the inventive instrumentation, which may be manufactured with matched pairs of inner and outer guides with a large number of surface contours that can be sequentially trailed on the surface to be grafted. Once a good match is obtained on the recipient cartilage surface, the same guides can be placed on the graft to find a perfect surface contour match, and this match may or may not be from the same location and orientation as the recipient site. With this technology, the precision of the surgical procedure for fresh osteochondral allografting can be improved, and the preparation of tissue engineered osteochondral constructs will be simplified when they become available. 
         [0015]    Osteochondral allografts have a long history of clinical success in the treatment of articular cartilage defects. One of the most commonly used techniques for osteochondral allografting has been the use of press-fit allograft cores placed into a recipient defect. Surface matching of these cores to provide a smooth transition from graft to native cartilage has been a technical challenge. The present invention is aimed at addressing this issue by preparing precontoured guides using manual technology, such as molds, or using computer technology, such as rapid prototyping, in such a way that the articular surface of the guides precisely matches the articular surface of both the allograft and the recipient bone. Once each of the guides are placed on the articular surface of either the donor or the recipient cartilage, guidepins can be used to secure the guides in such a way that the allograft core obtained and implanted leads to a precise surface match between the donor and recipient cartilage. This technology can be employed in transplant procedures for a variety of large joints including but not limited to the knee, shoulder, hip, and ankle joints. 
         [0016]    Other novel features characteristic of the invention, together with further objects and advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings, in which preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration and description only and are not intended as a definition of the limits of the invention. The various features of novelty that characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. The invention does not reside in any one of these features taken alone, but rather in the particular combination of all of its structures for the functions specified. 
         [0017]    There has thus been broadly outlined the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form additional subject matter of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based readily may be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0018]    The detailed description that follows makes reference to the annexed drawings wherein: 
           [0019]      FIGS. 1A and 1B  are, respectively, a cross-sectional side view in elevation and an upper perspective view of the non-contoured inner guide employed in the inventive method and apparatus; 
           [0020]      FIG. 2A  is an upper perspective view of the non-contoured outer guide; 
           [0021]      FIG. 2B  is an upper perspective view showing the non-contoured inner guide inserted into the non-contoured outer guide; 
           [0022]      FIG. 2C  is a side view in elevation thereof; 
           [0023]      FIG. 2D  is a cross-section side view in elevation thereof; 
           [0024]      FIG. 3A  is a perspective view, generally taken from a side elevation, showing an inner contoured guide combined with an outer contoured guide; 
           [0025]      FIG. 3B  is a perspective view, generally taken from the contoured end, thereof; 
           [0026]      FIGS. 4A and 4B  are each perspective views showing placement of the contoured guides on the femoral trochlea using a guidepin; 
           [0027]      FIGS. 5A and 5B  are first and second end perspective views of a reamer employed in prepared the recipient site; 
           [0028]      FIG. 6A  is a perspective views showing the recipient site reamer disposed in alignment with a reaming site immediately above a femur, while  FIG. 6B  shows the reamer in operation at the designated site; 
           [0029]      FIGS. 7A and 7B  are perspective views showing an allograft femur with inner and outer guides in place and held in place with guidewires; 
           [0030]      FIG. 8A  is a cross-sectional schematic view of a coring reamer, while  FIG. 8B  is a lower perspective view thereof; 
           [0031]      FIG. 9A  is a perspective view showing the outer contoured guide assembled with guidewires and with a coring reamer inserted therethrough, while  FIG. 9B  shows the coring reamer placed on allograft femur; 
           [0032]      FIG. 10A  is an upper perspective view showing the allograft femoral trochlea, while  FIGS. 10B and 10C  are superior and inferior views, respectively, showing the allograft cores taken from the allograft femoral trochlea using the coring reamer of  FIGS. 8A through 9B ; 
           [0033]      FIG. 11A  is a perspective view generally taken from the side showing the recipient femoral trochlea, while  FIGS. 11B-11C  show the allograft core implantation into the recipient site; 
           [0034]      FIGS. 12A and 2B  are, respectively, perspective views of the inner and outer contoured posterior femoral guides of a second preferred embodiment of the present invention, these being adapted for use in reconstructing a posterior femoral condyle of the human knee; 
           [0035]      FIGS. 13A and 13B  each show the posterior femoral guides placed on the femoral condyle; 
           [0036]      FIG. 14A  is a perspective view schematically showing the human knee, while  FIGS. 14B and 14C  are, respectively, a perspective view showing the contoured guides and the contoured guide fit to the patella; 
           [0037]      FIGS. 15A through 15C  are perspective views shows an alternative embodiment of contoured inner and outer guides adapted for use in reconstructing a human talus; and 
           [0038]      FIGS. 16A through 16C  are perspective views shows an alternative embodiment of contoured inner and outer guides adapted for use in reconstructing a humeral head. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]      FIGS. 1A through 2D  are a schematic cross-sectional and schematic perspective representation, respectively, of a non-contoured inner guide  10  and non-contoured outer guide  22 . The non-contoured inner guide consists of a superior end  11  having a generally planar superior surface  12  and an inferior end  13  having a generally planar inferior surface  14 , the superior surface having a circumferential expansion (rim)  16  that allows seating onto the outer guide superior edge  24 . The body  18  of the non-contoured guide is cylindrical. The inner guide also contains an axially disposed central aperture  20 , or through hole, that extends from the superior surface to the inferior surface and will accommodate a stabilizing guidepin of variable diameter. 
         [0040]    The non-contoured outer guide  22  (as shown in  FIGS. 2A through 2D ) is a tubular or cylindrical sleeve having a flat superior end  24  and a flat inferior end  26  and an inner aperture  30 . The diameter of the inner aperture is only slightly larger than the outer diameter of the matching non-contoured inner guide  10 , perhaps between 0.1 and 1.0 mm, for tight tolerances. The height of the outer guide is identical to the height of the body portion  18  inferior to the rim  16  of the matching inner guide. The outer guide also contains between two and six spaced apart peripheral, circumferentially disposed and axially oriented through holes or apertures  40  (four shown in  FIG. 2A ) to accommodate small guidewires for stabilizing the outer guide to bone as needed for recipient site preparation and donor allograft core harvesting and to identify and fix the geometric center of both the donor osteocondral allograft core and the recipient site. The diameter of these apertures is between 0.8 and 3 mm. 
         [0041]    In  FIGS. 2B and 2C , the non-contoured inner and outer guides are combined simply by inserting the body portion of the non-contoured inner guide into the central aperture of the outer guide.  FIG. 2D , is a schematic cross-sectional side view in elevation of this combination. When so inserted, the rim of the inner guide seats onto the upper or superior end of the outer guide and brings the planar inferior surface of the inner guide into co-planar relationship with the flat inferior end of the outer guide. 
         [0042]    The non-contoured inner and outer guides can be refashioned and prepared in such a way that they exactly match a variety of contours of the articular geometry of a specified joint. In this way they can be placed so that a guidepin placed through the aperture  20  in the inner guide is oriented precisely to allow harvest of an allograft with identical surface geometry and peripheral contour as the surface geometry and peripheral contour in the recipient joint. 
         [0043]      FIG. 3A  is a lateral perspective view of a contoured inner guide  50  and a contoured outer guide  70  specific to a femoral trochlea of a human knee. The contoured inner guide  50  includes a substantially planar cylindrical body, a substantially planar superior surface  52 , a contoured inferior end  54 , an expanded circumferential rim  56  encircling the body (not shown) proximate the superior surface, and a central aperture  60  or through hole running axially the entire length or height of the contoured inner guide. 
         [0044]    The contoured outer guide  70  includes a substantially planar upper rim or end  72  onto which the expanded circumferential rim  56  of the contoured inner guide is seated when it is inserted into the central aperture  74  (see esp.  FIG. 7B ) of the contoured outer guide. The contoured outer guide further includes a contoured inferior end  76  having a plurality of spaced apart peripheral, circumferentially oriented apertures  80  for the placement of stabilizing guidewires. 
         [0045]    In  FIGS. 4A and 4B , the combined inner contoured guide  50  and outer contoured guide  70  are placed on the exactly matched surface of the femoral trochlea  110  of the recipient in such a way that there is circumferential contact with the articular cartilage of the recipient area by both guides. Once this has been performed, a central guidepin  120  is passed through the central aperture of the contoured inner guide  50 , stabilizing both guides in place. Next, the contoured inner and outer guides are removed, leaving the central guidepin in place. 
         [0046]    In  FIGS. 5A and 5B , there is shown a recipient site reamer  130 , which is an instrument with elongate tubular body  132  operatively attached to a rotating power source (not shown) at its superior aspect. At its inferior aspect the reamer consists of between three and eight sharp radially disposed blades  134  (four shown in  FIGS. 5A and 5B ). The reamer also has an axially disposed central aperture or through hole  140  of between 0.8 and 3.0 mm which can accommodate the guidepin  120  shown in  FIG. 4 , and it is disposed over the guidepin to index and orient the reamer for precise drilling. Depth markers  136  are inscribed or otherwise placed on each of the blades of the recipient site reamer to give the surgeon an estimate of the depth of preparation of the recipient site. 
         [0047]      FIG. 6A  is a perspective view of the recipient femoral trochlea  110  with the central guidepin  120  placed through the inner and outer contoured guides as shown in  FIG. 4 . The recipient site reamer  130  is attached to a cannulated power source as is widely used by those skilled in the art of orthopaedic surgery and is passed over the guidepin onto the articular surface of the femoral trochlea. In  FIG. 6B , the recipient site  160  has been prepared exactly perpendicular to the guidepin and to the desired depth. 
         [0048]      FIG. 7A  is a perspective view of a donor femoral allograft trochlea  170  with the inner contoured guide  50  and the outer contoured guide  70  placed on the surface such that full contact is achieved on both guides. Next, the apertures of the outer guide  80  are used to fix the outer guide to the allograft using small guidewires  180 . Subsequently, the inner guide is removed as shown in  FIG. 7B . 
         [0049]      FIG. 8A  is a schematic cross-sectional side view in elevation of a cylindrical coring reamer  190  used for preparing a perfectly cylindrical allograft core. The inner diameter of the reamer is between 0.1 and 1.5 mm larger than the outer diameter of the recipient site reamer (or the radius of the reamer as measured from the center of the central aperture  140  to the outer edge or tip of any of the radially disposed blades) as shown in  FIG. 5 . This facilitates a press-fit fixation of the allograft. The coring reamer is essentially a tubular hole-saw with a plurality of cutting teeth  192  at its inferior end, a cylindrical interior volume  194  for capturing a drilled graft core, and a central aperture  200  that facilitates removal of the graft core. 
         [0050]      FIG. 9A  is a schematic perspective view showing the outer contoured guide  70  with its circumferential peripheral apertures  80  having small guidewires  180  inserted therethrough, and its central aperture  74  surrounding the cylindrical coring reamer  190  shown in  FIG. 8 . In  FIG. 9B  there is shown in perspective view a schematic representation of the combination from  FIG. 9A  placed onto the allograft femoral trochlea  170 . 
         [0051]      FIG. 10A  shows the allograft femoral trochlea  170  after removal of the combination contoured outer guide and reamer of  FIG. 9A . Using a variety of techniques, well known to those skilled in the art of orthopaedic surgery, the allograft core  220  can be removed from the allograft femur with variable thicknesses of attached bone.  FIGS. 10B and 10C  demonstrate the superior and inferior views of the allograft core after removal from the allograft femur. The thickness of attached bone can vary from 5 mm to 50 mm, depending on the surgeon&#39;s preference and the specific location. 
         [0052]      FIG. 11A  is a schematic perspective representation of the recipient femoral trochlea  110  from  FIG. 6B  after removal of the central guidepin. The allograft core  220  is placed into the recipient site and is partially seated in  FIG. 11B  and fully seated in  FIG. 11C . 
         [0053]      FIGS. 12A and 12B  show an alternative embodiment of inventive device adapted for use in preparing and implanting osteochondral allografts for the posterior femoral condyle of the human knee. The inner contoured guide  230  and the outer contoured guide  240  can be made in a variety of surface contours and sizes. In  FIGS. 12A  and B, the superior and inferior views, respectively, of the posterior femoral condylar guides are shown. The inner guide contains a central aperture  250  for placement of a guidepin into the recipient posterior femoral condyle, analogous to the femoral trochlear guides shown in  FIG. 4 . The outer guide contains peripheral circumferentially located apertures  260  for fixation to the allograft posterior femoral condyle. 
         [0054]      FIGS. 13A  and B are perspective views showing the posterior femoral inner and outer contoured guides placed on the femoral condyle  270  prior to placement of the central guidepin in the inner guide aperture  250 . Once this has been achieved, the core is harvested in the same fashion as shown for the trochlea in  FIGS. 7-10 . 
         [0055]      FIG. 14A  is a perspective view showing a reconstruction of the human knee  280 , including the patella  282 .  FIG. 14B  is a representation of the embodiment of the present invention aimed at treating the patella with an inner contoured guide  290  and an outer contoured guide  300  matched to the articular surface of the patella. After exposure of the articular surface of the patella, the guides are placed on the articular surface of the patella such that the central aperture  310  of the inner guide can be used for passage of a central guidepin. The recipient site reamer shown in  FIGS. 6A and 6B  can be used to prepare a recipient site on the patella to the desired depth. Next, an allograft patellar core can be implanted in the identical fashion as has been described for the femoral trochlea shown in  FIGS. 7-10 . 
         [0056]      FIG. 15  shows yet another embodiment of the present invention, this one adapted for use in treating the human talus  320 . Specific guides contoured to the central, medial, and lateral aspects of the talar dome in various sizes can be manufactured. In  FIGS. 15A  and B, the superior and inferior views respectively of the contoured inner contoured guide  330  and outer contoured guide  340  are demonstrated. After placement and full articular contact of both guides on the surface, a central guidepin is placed in the central aperture  350  of the inner guide and into the recipient defect. In  FIG. 15C , there is shown a perspective view of the medial talus  320  with both guides placed on the articular surface. The subsequent technique for preparation of the allograft core for the talus follows the technique shown previously for the femoral trochlea in the preceding figures. 
         [0057]      FIGS. 16A-16C  show another embodiment of the present invention, this being adapted for use in treating the human proximal humerus.  FIG. 16A  is a perspective view of a human proximal humerus  400 . In  FIG. 16B , an inferior view of the combination of inner contoured guide  360  and outer contoured guide  370  matching the radius of curvature and contour of the humeral articular surface is shown. In  FIG. 16C , the inner and outer guide combination is placed on the articular surface of the humerus  400  immediately prior to placement of a central guidepin in the aperture  380  (see  FIG. 16B ) of the inner guide. The remaining portion of the preparation of both the recipient and the donor grafts is identical to that shown for the femoral trochlea in the preceding figures. 
         [0058]    The above disclosure is sufficient to enable one of ordinary skill in the art to practice the invention, and provides the best mode of practicing the invention presently contemplated by the inventor. While there is provided herein a full and complete disclosure of the preferred embodiments of this invention, it is not desired to limit the invention to the exact construction, dimensional relationships, and operation shown and described. Various modifications, alternative constructions, changes and equivalents will readily occur to those skilled in the art and may be employed, as suitable, without departing from the true spirit and scope of the invention. Such changes might involve alternative materials, components, structural arrangements, sizes, shapes, forms, functions, operational features or the like. 
         [0059]    Therefore, the above description and illustrations should not be construed as limiting the scope of the invention, which is defined by the appended claims.