Abstract:
Systems, methods and device for tibial resection comprise a first cutting guide and a second cutting guide. The first cutting guide ( 12 ) is configured to overlay a portion of the tibia and to direct a cutting instrument in a plane. The first cutting guide has a length extending from a generally medial portion of the tibia to a generally lateral portion of the tibia. The first cutting guide has a depth extending in a posterior direction generally perpendicular to the length and a groove extending along the length and depth of the first cutting guide such that the groove extends along a generally transverse plane. The second cutting guide ( 34 ) is oriented at an angle to the first cutting guide and configured to extend generally in a posterior direction from the first cutting guide ( 12 ). The second cutting guide limits the cutting instrument in the transverse plane from cutting bone.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/812,849 filed Jun. 12, 2006. The disclosure of this prior application is incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to systems, methods, and devices for bone resection. More particularly, the present invention relates to systems, methods, and devices for tibial resections and soft tissue guided bone resections. 
         [0004]    2. Related Art 
         [0005]    Previous cutting instruments are all guided outside the bone, and once the instrument enters the bone it is no longer guided. Problems, such as tip deflection and skiving can affect bone cuts, implant alignment, and fixation. Previous instrumentation also will not fit under tight soft tissues, necessitating resection of those tissues or movement of those tissues. 
       SUMMARY 
       [0006]    A resection guide for a tibia comprises a first cutting guide and a second cutting guide. The first cutting guide is configured to overlay a portion of the tibia and to direct a cutting instrument in a plane. The first cutting guide has a length extending from a generally medial portion of the tibia to a generally lateral portion of the tibia. The first cutting guide has a depth extending in a posterior direction generally perpendicular to the length and a groove extending along the length and depth of the first cutting guide such that the groove extends along a generally transverse plane. The second cutting guide is oriented at an angle to the first cutting guide and configured to extend generally in a posterior direction from the first cutting guide. The second cutting guide limits the cutting instrument in the transverse plane from cutting bone. 
         [0007]    Additionally, a resection guide may further comprise a third cutting guide configured to extend generally orthogonal to the transverse plane of the first cutting guide and oriented in the posterior direction of the second cutting guide. 
         [0008]    Another embodiment may include a resection guide wherein the first and second cutting guides are configured to cut a medial portion of the tibia. 
         [0009]    Additionally, a resection guide may further comprise a support structure. The support structure has a bone fixator configured to fixate the resection guide to the bone. The support structure may additionally include a cutting guide support configured to orient the varus/valgus angle of the first cutting guide. 
         [0010]    Another embodiment may include a resection guide wherein the support structure has a port configured to receive a lateral resection guide. 
         [0011]    One embodiment may include a resection guide wherein the lateral resection guide is fixed to the support structure with a connector. 
         [0012]    Another embodiment may include a resection guide wherein the bone fixator is an extramedullary rod guide. 
         [0013]    Additionally, the support structure may further comprise an offset configured to position the bone fixator away from the cutting guide support such that the bone fixator is outside the surgical field. 
         [0014]    Additionally, the support structure may further comprise an offset configured to position the cutting guide support between the tibia and the patellar tendon and further position the bone fixator over the patellar tendon. 
         [0015]    In one embodiment, the second cutting guide is a pin. 
         [0016]    Additionally, the pin may include a cutout configured to retain the cutting instrument. 
         [0017]    Another embodiment of the second cutting guide may include a sleeve having a cutout to retain the cutting instrument. 
         [0018]    In another embodiment, the second cutting guide may extend into the tibia. 
         [0019]    A method of resecting a portion of a tibia includes the step of orienting a first cutting plane of a first cutting guide in a transverse plane in a medial/lateral direction. The first cutting plane sets the varus/valgus angle of the cutting plane. Another step installs a second cutting guide in the first cutting plane. The second cutting surface extends distally in the first cutting plane and limits the range of motion of a cutting instrument in the direction of the medial/lateral resection. Another step cuts the tibia from the outer surface of the bone along the first cutting plane in the first cutting guide to the second cutting guide. 
         [0020]    Another embodiment further comprises the step of orienting a third cutting guide generally perpendicular to the first cutting plane. The third cutting guide extends in a sagittal plane. Another step includes cutting the tibia with the cutting instrument from a proximal portion along the sagittal plane of the third cutting guide distally until the cutting instrument contacts the second cutting guide. 
         [0021]    In another embodiment, the installing step may further comprise the step of drilling a hole through the bone such that the hole is aligned along the first cutting plane. 
         [0022]    Additionally, the installing step may further comprise the step of inserting a pin into the bone. 
         [0023]    Additionally, the second cutting guide may be a sleeve on a pin. The installing step further comprises the step of removing the pin from the sleeve when the sleeve is placed in the bone. 
         [0024]    In one embodiment the method further comprises the step of attaching a lateral cutting guide to the first cutting guide after the cutting step. 
         [0025]    In another embodiment the method further comprises the step of fixing the cutting guide to the bone. 
         [0026]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the written description serve to explain the principles, characteristics, and features of the invention. In the drawings: 
           [0028]      FIG. 1  is view of an embodiment of a tibial resection guide. 
           [0029]      FIG. 2  is a view of a portion of the tibial resection guide of  FIG. 1  placed on a tibia and receiving a cutting guide. 
           [0030]      FIG. 3  is a view of the portion of the tibial resection guide of  FIG. 2  with the cutting guide installed. 
           [0031]      FIG. 4  is a view of an embodiment of a tibial resection guide for a medial resection. 
           [0032]      FIG. 5  is a view of an embodiment of a lateral resection guide oriented relative to a medial resection. 
           [0033]      FIG. 6  is another view of the embodiment of the lateral resection guide of  FIG. 5 . 
           [0034]      FIG. 7  is a view of an embodiment of a portion of tibial resection guide for a medial resection. 
           [0035]      FIG. 8  is another view of the embodiment of the tibial resection guide of  FIG. 7 . 
           [0036]      FIG. 9  is a view of other portions of the tibial resection guide of  FIG. 7 . 
           [0037]      FIG. 10  a view of an embodiment of a tibial resection guide. 
           [0038]      FIG. 11  is an end view of an embodiment of a pin having a cutout portion. 
           [0039]      FIG. 12  is an end view of another embodiment of a pin having a cutout portion. 
           [0040]      FIG. 12  is an end view of another embodiment of a pin having a cutout portion. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0041]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0042]    Turning to the drawing figures,  FIG. 1  is view of an embodiment of a tibial resection guide  10 . The guide  10  includes a medial cutting guide  12 , a lateral cutting guide  14  and a bone fixator  18 . The bone fixator  18 , in this embodiment, is an extramedullary (EM) rod connector having an extramedullary rod guide  20  and a tightening knob  22 . The medial and lateral cutting guides  12  and  14  include set screws  24  and  26  which lock the medial and lateral cutting guides  12  and  14  in place along a variable medial/lateral slots (slot  28  for the lateral side). Pin slots  30  and  32  in the cutting guides  12  and  14  are configured to receive cutting guides. Vertical cutting guides  34  and  36  are oriented above the pin slots  30  and  32 . 
         [0043]    The bone fixator  18  is configured to fix the cutting guide to the bone. The EM rod guide may be oriented to account for varus/valgus angle for the knee. Additionally, fixation pins may be used though openings in the resection guide  10  to fix the resection guide  10  to the bone. When the resection guide  10  is properly aligned and oriented on the EM rod, then the knob  22  may be tightened to fix the resection guide  10  in place. 
         [0044]    The cutting guides  12  and  14  are oriented with respect to the bone fixator  18  to align the cutting surfaces for the medial and lateral portions of the tibia. The set screws  24  and  26  set the medial and lateral cutting guides  12  and  14  in place in the medial/lateral direction. When the set screws  24  and  26  are loosened, then medial and lateral cutting guides may be variably positioned laterally and medially. Additionally, the set screws  24  and  26  may be removed to allow for the cutting guides  12  and  14  to be individually removed. The cutting guides  12  and  14  may be used independently, then, to minimize the size of the resection guide  10 . A smaller resection guide  10  may help to minimize the incision size and minimize soft tissue resections or displacements. 
         [0045]    The cutting guides  12  and  14  include horizontal cutting planes and vertical cutting planes. The horizontal and vertical cutting planes define the horizontal and vertical cutting surfaces for the tibia. When these guides  12  and  14  are used, the tibia will have medial and lateral resections with a shelf maintaining natural bone for the medial condyle between the resections where soft tissue may be maintained. For example, posterior and anterior cruciate ligaments attach to the tibia along the medial condyle of the tibia, and may be saved when the medial and lateral compartments are individually cut. 
         [0046]    In operation, the guide  10  is placed on an EM rod and fixed to the rod. The angle of the rod fixes the varus/ valgus rotation of the resection guide  10 . Generally, the medial compartment is resected first. The medial cutting guide  12  is positioned on the tibia. A pin (shown, for example, in  FIG. 2 ) is inserted into the tibia. The horizontal cut in a transverse plane to the tibia is cut. The pin is set along the transverse plane. The vertical cutting guide  34  is positioned at an angle to the transverse plane and extends to the pin. Thus, the pin is in the transverse plane formed by the horizontal cutting guide and the sagittal plane of the vertical cutting guide. The cut in the transverse plane is cut to the pin, and the sagittal plane is cut down from above the tibia to the pin. 
         [0047]    The pin cutting guide limits the cuts in both the transverse plane and sagittal plane. This minimizes the possibility of undercutting the resection. This also protects from overextending the cuts which may damage soft tissue. By creating a physical stop in the path of the cuts, the cuts may not extend past the stops. The pin may also provide a fillet at the corner to reduce stress risers in the bone. Additionally, as discussed below, the pin may limit tip deflection and better align or stabilize the cutting instruments during the cuts. 
         [0048]    Turning now to  FIG. 2 ,  FIG. 2  is a view of a portion of the tibial resection guide  10  of  FIG. 1  placed on a tibia  40  and receiving an anterior/posterior cutting guide  42 . The lateral cutting guide  14  is positioned against a lateral portion of the tibia  40 . The anterior/posterior cutting guide  42  may extend anterior/ posterior into the tibia and includes an outer sheath  44  and a pin  46 . The anterior/posterior cutting guide  42  is inserted into a receiving slot  48  in the transverse guide of the lateral cutting guide  14 . The anterior/posterior cutting guide  42  may be driven into the bone. Alternatively, a hole may be drilled into the bone and the anterior/posterior cutting guide  42  may be inserted into the receiving slot  48 . Once the anterior/posterior cutting guide  42  is positioned within the receiving slot  48 , the pin  46  may be removed from the sheath  44  leaving a cutting slot, as shown in  FIG. 3 . 
         [0049]    Turning now to  FIG. 3 ,  FIG. 3  is a view of the portion of the tibial resection guide of  FIG. 2  with the cutting guide  42  installed. The pin of the anterior posterior cutting guide  42  has been removed leaving the sheath  44  in the receiving slot  48 . An A/P sheath slot  50  extends from the anterior portion of the tibia  40  to the posterior portion of the tibia  40 . The sheath slot  50  allows for a cutting instrument to be inserted along the sheath slot  50  to start the cut and control the tip of the cutting instrument. The cut continues within a horizontal slot  52  to the lateral side of the tibia. The sheath slot  50  also stabilizes the transverse cut and properly aligns the transverse cut. As the transverse cut is made, the cut may not extend more medially than the sheath slot  50 . 
         [0050]    A vertical slot  54  extends from a proximal portion of the tibia  40  to the sheath  44 . In this embodiment, the sheath is oriented as a stop and does not create a starting point inferiorly for the vertical cut. However, the receiving slot  48  and the sheath slot  50  may be oriented so that the vertical slot  54  may be aligned with the sheath slot  50 . 
         [0051]    Turning now to  FIG. 4 ,  FIG. 4  is a view of an embodiment of a tibial resection guide  60  for a medial resection. The tibial resection guide  60  is connected to the bone with a spike rod  62 . The spike rod  62  attaches to an EM guide  66  of the tibial resection guide  60 . Pins  64  attach the medial cutting guide to the bone. Additional bone fixation may be achieved with a pin through a pinhole  68 . A variable M/L slot  67  allows for the medial guide  60  to be moved medially and laterally with respect to the tibia, and is thus similar to the slot  28  of  FIG. 1 . A set screw  72  fixes the M/L position of the cutting guide  60 . 
         [0052]    The pins  64  may be of different heights so that a first pin may be hammered into the tibia first, and then the spike rod (and thus the EM rod guide  66  and cutting guide  60 ) may be rotated before the second, shorter pin  64  is knocked into the bone. Once the second shorter pin is placed, the guide  60  is fixed to the bone. 
         [0053]    A medial cutout  76  shows the transverse cut  78  and the vertical cut  80  of the tibia. An A/P pin slot  82  is positioned so that an A/P pin would be placed at the intersection of the transverse cut  78  and the vertical cut  80  so that when the transverse and vertical cuts are made, the A/P pin would limit the lateral edge of the transverse cut and the inferior edge of the vertical cut. 
         [0054]    Turning now to  FIG. 5 ,  FIG. 5  is a view of an embodiment of a lateral resection guide  90  oriented relative to a medial resection. For example, the lateral resection guide  90  may be used with the medial resection guide of  FIG. 4 . The lateral guide  90  includes a medial pad  92  which orients a lateral cutting guide  93  to the tibia. A set screw  94  sets the medial lateral position of the lateral resection guide  90  in a slide  96 . Fixation is achieved by extending the knee and having the medial condyle of the femur pressing down on the medial pad  92 . Additionally, pinholes  100  may be used to fixate the lateral resection guide  90  to the bone. Extending the femur also relaxes the patella, moving the patella out of the way for lateral cuts. The horizontal and vertical cutting guides for the lateral resections are operated similar to the cuts discussed previously. 
         [0055]    The cuts may be formed either using a sagittal saw or a reciprocating saw. When using a reciprocating saw, then the preferred cut starts at the A/P guide and progresses toward the posterior of the tibia within the slot of the A/P guide. After completing a cut from the anterior to the posterior of the tibia, then the blade is pushed out within the transverse slot of the lateral guide  94 . 
         [0056]    Turning now to  FIG. 6 ,  FIG. 6  is another view of the embodiment of the lateral resection guide of  FIG. 5 . The medial pad  92  sits on the medial tibial cutout  76 . Any variation in the medial cut  76  will be transferred to the lateral side through the medial pad  92 . Thus, misalignment between the medial and lateral cuts is minimized through the sequential cutting of first the medial than the lateral compartments. 
         [0057]    Turning now to  FIGS. 7 and 8 ,  FIG. 7  is a view of an embodiment of a portion of tibial resection guide  110  for a medial resection. An extra medullary rod  112  fixates the resection guide  110  with a step down block  114 . Pins  116  further fixate the guide  110  to the bone. A medial cutting guide  120  may be moved medially/laterally with a knob  122  and set in place by a set screw  124 . An A/P cutting guide  126  through the medial cutting guide  120  limits the cuts of a medial cutout.  FIG. 8  is another view of the embodiment of the tibial resection guide  110  of  FIG. 7 . A medial cutout  140  shows a filleted cut surface  142  at the intersection of a transverse cut  144  and a vertical cut  146   
         [0058]    Turning now to  FIG. 9 ,  FIG. 9  is a view of other portions of the tibial resection guide  110  of  FIG. 7 . A lateral cutting guide  160  is received in the same slot as the medial guide of  FIGS. 7 and 8 . The knob  122  may orient the lateral cutting guide  160  in the medial/ lateral direction. Because the resection guide  110  is fixed in the same orientation as when the medial cuts were made, the relative orientation of the medial cuts to the lateral cuts are consistent. 
         [0059]    The step down block  114  is an offset that moves part of the bone fixation and the part that orients the guide  110  away from the cutting planes and cutting surfaces. This allows for more access and added views of the cutting planes. 
         [0060]    Turning now to  FIG. 10 ,  FIG. 10  a view of an embodiment of a tibial resection guide  180 . A medial cutting guide  182  and a lateral cutting guide  184  are received on a cutting guide support. In this embodiment, the cutting guide support is a guide post  186 . A bone fixator  188  is connected to the post  186  by an offset  190 . Set screws  192  fix the cutting guides  182  and  184  to the post  186 . The post  186  allows for medial/lateral movement of the cutting guides  182  and  184  along tracks  196  and  198  respectively. 
         [0061]    The tibial resection guide  180  is generally smaller in size than conventional resection guides. The offset  190  is shaped to allow for the post  186  to be inserted within an incision while the bone fixator  188  remains outside the incision. The curve in the offset  190  positions the post  186  between the tibia and the patellar tendon and position the bone fixator  188  over the patellar tendon. In order to minimize the size of the resection guide  180 , the cutting guides  182  and  184  may be used individually. 
         [0062]    Turning now to  FIGS. 11-13 ,  FIG. 11  is an end view of an embodiment of a pin  200  having a cutout portion  202 .  FIG. 12  is an end view of another embodiment of a pin  210  having a cutout portions  212 .  FIG. 12  is an end view of another embodiment of a pin  220  having a cutout portions  222 . Each of these pins  200 ,  210 , and  220  may be used as pins with the embodiments of resection guides previously discussed. The cutout portion  202  is a portion that is limited to a single slot in the A/P direction of the pin  200 . The cutout portions  212  and  222  are configured to capture a cutting instrument in orthogonal planes in the A/P direction. While cutout portions  212  extend tangential to the cross section of the pin  210 , the cutout portions  222  extend along secants of the cross section of the pin  220 . While the cutouts  212  and  222  are positioned orthogonally, the cutouts  212  and  222  may be positioned at any angle relative to one another. Additionally, sheaths may be used with the pins to fill the cutouts initially if the pins are driven into the bone instead of placed within pre-drilled holes. 
         [0063]    As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.