Abstract:
A bone resection guide, particularly for an ulna, utilizes anatomical reference points of the ulna to establish an optimal position for a prosthesis. The bone resection guide provides a guiding instrument that allows a surgeon to remove only bone that needs to be removed for precise placement of the end prosthesis. A method of resecting bone from the ulna in preparation of prosthetic implantation using the bone resection guide matches an elbow axis finder with a particular size of an ulna fossa of the patient. Once matched, a sized resection template, directly related to the shape of the prosthesis, is used as a resection guide. Incorporated into the bone resection guide are known anthropometric qualities when providing resection surfaces. This enhances the probable position of the implant.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application Serial No. 60/368,787, filed Mar. 29, 2002. 
     
    
     
       TECHNICAL FIELD OF THE INVENTION  
         [0002]    The present invention relates to surgical devices particularly bone resection devices and, more particularly, to a surgical device and method of use for bone resection of the proximal ulna.  
         BACKGROUND OF THE INVENTION  
         [0003]    A common problem in the orthopaedic industry is the need for accurate bone resection prior to implantation of a prosthesis, particularly of prosthetic joints. Appropriate positioning of the prosthesis has been shown in many cases to be a leading factor in long term stability of such prosthetic joints. This is true with respect to all types of prosthetic joints. The industry, however, has relatively neglected the ulna at the elbow joint.  
           [0004]    A current standard of practice is to perform bone resection by hand without guidance of any kind, regardless of implant type. With respect to total elbow arthroplasty (TEA), loosening of the ulnar stem of the elbow prosthesis is a commonly reported complication. This complication raises questions related to surgical technique and its relationship to the complication.  
           [0005]    As indicated, little work has been done specifically for the ulna in the area of designing precision surgical techniques for resection of the ulna bone and implant (prosthesis) positioning. A current and primary benchmark for arthroplasty for the past twenty years has been the Coonrad-Morrey prosthesis from Zimmer of Warsaw, Indiana. The Coonrad-Morrey system, however, provides very little in terms of instrumentation for determining and positioning the implant relative to existing anatomy of a patient. One device for assistance in resection of the ulna for a TEA is the Solar Elbow™ from Stryker Howmedica Osteonics of Kalamazoo, Mich. The Solar Elbow™ provides with its instrumentation a device designed to assist in resection of the ulna to a shape complementing the implant. The Solar Elbow™ provides a template shaped to complement the implant that is held up to the bone and which is used to cut along. One problem with the Solar Elbow™ resection device is that there are no ties or reference to existing anatomy.  
           [0006]    In U.S. Pat. Nos. 4,624,250 issued on Nov. 25, 1986 and 4,718,414 issued on Jan. 12, 1988 to Saunders et al., there is disclosed an instrument for elbow surface replacement arthroplasty (the “Saunders instrument”). The Saunders instrument and method of use bases resection of an ulna for elbow arthroplasty on the patient&#39;s humeral anatomy, particularly the condyles of the humerus. Particularly, Saunders uses the condyles of the humerus to establish a center of rotation for the humerus and relates such back to the ulna for resection thereof. Several problems, however, exist with the Saunders instrument and method of use. One problem is that there is no method for accounting for soft tissue balance. Resection is made from the anatomical center of the humerus with little consideration of the ulna. Another problem is that many cases exist in elbow arthroplasty in which the condyles of the humerus have been fractured or otherwise rendered useless, and thus cannot be used as a reference.  
           [0007]    What is thus needed is a bone resection guide and/or method of use that utilizes the ulna as a reference for resection of the ulna.  
           [0008]    What is thus further needed is a bone resection guide and/or method of use that allows resection of an ulna in a manner that allows precise placement of a final prosthesis or implant.  
         SUMMARY OF THE INVENTION  
         [0009]    The subject invention is a bone resection guide or jig and/or a method or procedure of use in the resection of bone. Particularly, the subject invention is a bone resection guide or jig and/or a procedure of use for resection of bone of an ulna in preparation of a prosthetic implant (prosthesis).  
           [0010]    In one form, the subject invention provides a method of resecting bone from an ulna in preparation of prosthetic implantation. The method includes the steps of: (a) creating a reference axis of natural elbow rotation of a patient with respect to an ulna of a patient; (b) selecting a resection template from one of a plurality of dimensions of resection templates; (c) providing the selected resection template to and with respect to the created reference axis of natural elbow rotation; and (d) resecting a portion of the ulna according to the selected resection template.  
           [0011]    In another form, the subject invention provides a method of resecting bone from an ulna in preparation of prosthetic implantation. The method includes the steps of: (a) placing a selected mock trochlea into a trochlear notch of an ulna of a patient; (b) temporarily fixing the mock trochlea in the trochlear notch of the ulna; (c) placing a selected resection template onto the mock trochlea; and (d) resecting bone from the ulna according to the resection template.  
           [0012]    In yet another form, the subject invention provides a bone resection guide for an ulna. The bone resection guide includes a frame, a guide block, and a mock trochlea holder. The guide block is adjustably carried by the frame and is operative to contact an olecrannon of an ulna of a patient. The mock trochlea holder is adjustably carried by the frame and is operative to temporarily retain a selected mock trochlea in a trochlear notch of the ulna of the patient.  
           [0013]    The subject invention utilizes the existing anatomy (i.e. “boney landmarks”) of an ulna to determine an appropriate location for an implant. The subject invention incorporates known qualities of the ulnar anatomy therein and into the position of the final implant. Further, the subject invention offers a surgeon a bone conserving approach, as well as an easy replication of the resection surface for further bone removal. Additionally, the subject invention complements the final implant or prosthesis particularly taking into account the center of rotation positions available through multiple sizes of ulnar bearings. Still further, the existing center of elbow rotation is approximated, allowing better balancing of soft tissue, thus leading to possibility of greater range of motion. Finally, the subject invention is low profile, thus requiring minimal incision sizes. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view of an exemplary bone resection guide or jig in accordance with the principles of the subject invention;  
         [0015]    [0015]FIG. 2 is a perspective view of a guide frame for the exemplary bone resection guide of FIG. 1;  
         [0016]    [0016]FIG. 3 is an enlarged perspective view of a portion of the guide frame taken along circle  3 - 3  of FIG. 2;  
         [0017]    [0017]FIG. 4 is an enlarged plan view of a guide stem of the exemplary bone resection guide of FIG. 1;  
         [0018]    [0018]FIG. 5 is an enlarged, partial top view of an end of a guide block of the exemplary resection guide of FIG. 1;  
         [0019]    [0019]FIG. 6 is an enlarged plan view of a spool peg of the exemplary bone resection guide of FIG. 1;  
         [0020]    [0020]FIG. 7 is an enlarged plan view of a resection template mounting screw;  
         [0021]    [0021]FIG. 8 is a top plan view of the exemplary bone resection guide of FIG. 1;  
         [0022]    [0022]FIG. 9 is a side view of one size of an exemplary spool/mock trochlea for the exemplary bone resection guide of FIG. 1;  
         [0023]    [0023]FIG. 10 is a side view of the exemplary spool/mock trochlea taken along line  10 - 10  of FIG. 9;  
         [0024]    [0024]FIG. 11 is a perspective view of the exemplary bone resection guide of FIG. 1 with one size of an exemplary spool/mock trochlea attached thereto;  
         [0025]    [0025]FIG. 12 is a top plan view of the exemplary bone resection guide of FIG. 1 with one size of an exemplary spool/mock trochlea attached thereto shown in sectional;  
         [0026]    [0026]FIG. 13 is a front view of one size of an exemplary resection guide template for the exemplary bone resection guide of FIG. 1;  
         [0027]    [0027]FIG. 14 is a side view of the exemplary resection guide template for the exemplary bone resection guide taken along line  14 - 14  of FIG. 13;  
         [0028]    [0028]FIG. 15 is a side view of the mounting rod of the exemplary resection guide template for the exemplary bone resection guide taken along line  15 - 15  of FIG. 14;  
         [0029]    [0029]FIG. 16 is a top plan view of the exemplary bone resection guide of FIG. 1 with one size of an exemplary spool/mock trochlea attached thereto shown in sectional with one size of an exemplary resection guide template attached thereto;  
         [0030]    [0030]FIG. 17 is a side view of an ulna being initially prepared for soft tissue balance;  
         [0031]    [0031]FIG. 18 is a side view of the ulna with an intramedullary rod in the prepared ulna;  
         [0032]    [0032]FIG. 19 is a side view of the ulna undergoing soft tissue balance; and  
         [0033]    [0033]FIG. 20 is a perspective view of a spool, resection guide template, and bone resection guide assembly in position with respect to an ulna. 
     
    
       [0034]    Corresponding reference characters indicate corresponding parts throughout the several views. Like reference characters tend to indicate like parts throughout the several views.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0035]    While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein by described in detail. It should be understood, however, that there is no intent to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.  
         [0036]    Referring now to FIG. 1 there is shown an exemplary embodiment of a surgical device, particularly a bone resection/resector guide or jig, generally designated  20  (hereinafter, collectively “bone resection guide”). The bone resection guide  20  is configured, adapted or operative to allow a surgeon to determine a proper and/or appropriate resection area or portion of an ulna and allow resection of the determined proper/appropriate resection area particularly in preparation of a prosthetic implant (i.e. an elbow prosthesis/prosthetic component).  
         [0037]    The resection guide  20  has an exemplary resection guide frame assembly  22 , an exemplary resection guide block assembly  24 , an exemplary resection spool/mock trochlea retention and adjustment assembly  26 , and an exemplary bone alignment/axis finder/locator assembly  28 . Each assembly is preferably manufactured from a suitable material such as a metal, for steel, stainless steel, an aluminum alloy, or a polymeric material, unless specified otherwise. Other material or materials may be used as appropriate for the industry and/or for such surgical instruments.  
         [0038]    The exemplary resection guide frame assembly  22  provides a main frame or support for the other components (assemblies) of the subject bone resection guide  20 . As such, the subject resection guide frame assembly  22  may be configured differently than that shown without departing from the concept and such is contemplated. The resection guide frame assembly  22  supports the resection guide block assembly  24 , the resection guide block assembly  24 , the resection spool/mock trochlea retention and adjustment assembly  26 , and the humeral bone alignment/axis finder/locator assembly  28 . Particularly, the resection guide block assembly  24 , the resection spool/mock trochlea retention and adjustment assembly  26 , and the bone alignment/axis finder/locator assembly  28  are all adjustably and/or removably supported or retained on or by the resection guide frame assembly  22 .  
         [0039]    With additional reference to FIG. 2, the exemplary resection guide frame assembly  22  will be described with greater particularity. The resection guide frame assembly  22  includes a guide frame  30  that comprises a first leg, arm or the like  32  and a second leg, arm or the like  34 . It should be appreciated that the nomenclature “first” and “second” are arbitrary and thus may be interchanged without consequence. The first and second legs  32  and  34  are joined at respective ends thereof essentially perpendicular to form a backwards “L”. The first and second legs  32  and  24  are shown as bars, but may be rods or other-shaped members. The first leg  32  has an eyelet or holder  36  on one end thereof that is distal from the joining end/point of the first and second legs  32  and  34 . The eyelet  36  has a threaded bore  38 . As described below in greater detail and shown in FIG. 1, the threaded bore  38  threadedly receives a component of the resection guide block assembly  24 . The second leg  34  has an eyelet or holder  40  on one end thereof that is distal from the joining end/point of the first and second legs  32  and  34 . The eyelet  40  has a threaded bore  42 . As described below in greater detail and shown in FIG. 1, the threaded bore  38  threadedly receives a component of the resection spool/mock trochlea retention and adjustment assembly  26 .  
         [0040]    The guide frame  30  also includes a retention frame  44  that is positioned on the first leg  32 . With additional reference to FIG. 3, the retention frame  44  includes a first wall or member  46  that is situated essentially perpendicular to a top surface of the first leg  32  and a second wall or member  48  that is situated essentially perpendicular to the top surface of the first leg  32  and spaced from the first wall  46 . It should be appreciated that the nomenclature “first” and “second” are arbitrary and thus may be interchanged without consequence. The retention frame  44  also includes a top wall or member  50  that spans from the first wall  46  to the second wall  48 . As such, the top wall  50  is essentially parallel to the top surface of the first leg  32 . The walls  46 ,  48 , and  50  define an opening  52  that is configured to retain a component of the humeral bone alignment/axis finder/locator assembly  28  (see FIG. 1). As such, the opening  52  is configured in like manner to the component of the bone alignment/axis finder/locator assembly  28  in order to receive and/or accommodate the component. The opening  52  may thus be configured differently in correspondence to the shape of the component of the bone alignment/axis finder/locator assembly  28 .  
         [0041]    Referring back to FIG. 1, the resection guide block assembly  24  of the resection guide  20  will be discussed. The resection guide block assembly  24  is configured, adapted and/or operative to contact the ulna and particularly the posterior aspect of the olecranon of the ulna when the bone resection guide  20  is installed. The resection guide block assembly  24  includes a guide stem  54  and a guide block  58  carried by the guide stem  54 . The guide stem  54  is adjustable with respect to the guide frame  30 , particularly with respect to the first leg  32 . With additional reference to FIG. 4, the guide stem  54  is shown. The guide stem  54  includes threads  55  and a knob, sphere, rotundity, or the like  56  at one end thereof. The threads  55  preferably extend the length of the guide stem  54 . The knob  56  is preferably smooth about its face or outer surface.  
         [0042]    As shown in FIG. 1, the guide stem  54  is thus threadedly received in the threaded bore  38  of the eyelet  36 . As such, the guide stem  54  is axially adjustable about the length of the threads  55  of the stem with respect to the eyelet  36 . Therefore, in one direction of rotation of the guide stem  54 , the guide stem  54  axially advances or moves toward an ulna (up and to the right in FIG. 1) and in another direction of rotation of the guide stem  54 , the guide stem  54  axially advances or moves away from the ulna (down and to the left). Such translation of the guide stem  54  is represented by the arrow  90  in FIG. 8. Since the guide block  58  is coupled to or carried by the guide stem  54 , the guide block  58  also advances towards or away from the ulna when the guide stem  54  is rotated in one direction and rotated in another direction. Again, such translation of the guide block  58  is represented by the arrow  90  in FIG. 8.  
         [0043]    The guide block  58  includes a cavity  62  that is shaped in converse to the knob  56  and is therefore configured, adapted and/or operative to receive the knob  56 . The knob  56  and the cavity  62  cooperate to allow the guide block  58  to pivot, rotate, swivel, or move about the knob  56 . In this manner, the guide block  58  is positionable in an almost infinite number of positions with respect to the knob  56  and/or the guide shaft  54 . In one form, the guide block  58  is formed of two components each of which includes a portion of the cavity  62  such that when the two components are coupled together with the knob  56  in therein, the knob  56  is captured in the cavity  62 .  
         [0044]    The guide block has a front surface  60  that is rounded, curved or arcuate-shaped. Referring additionally to FIG. 5, a top view of the front surface  60  of the guide block  58  is seen. The curved front surface  60  preferably has a curvature that corresponds to a typical curvature of a posterior aspect of an olecranon of an ulna, but not necessarily. In addition, as best seen in FIG. 5, the front surface  60  includes a plurality of grips in the form of spikes  64 . The spikes  64  allow the guide block  58  to be generally non-movably, but releasably, retained against the olecranon of the ulna during use. While three spikes  64  are shown, it should be appreciated that the number of spikes  64  is variable from one to many. As well, the height of each spike  64  may be the same or different than that of the other spikes. The overall and/or individual spike height may be variable.  
         [0045]    Additionally, the bone resection guide  20  is contemplated for,use with guide blocks of various sizes. Particularly, while a guide block  58  of only one size is used at a particular time (i.e. for a particular resection procedure), the bone resection guide  20  can use a different guide block  58  for each resection procedure. The various sizes of guide blocks  58  correspond to various sizes of olecranons. The guide blocks  58  may be provided in useful increments so that a useful range of sizes of guide blocks  58  is provided with the bone resection guide  20 . The same guide shaft  54  may be used or different guide shafts  54  each having a different sized knob  56  may be provided for each different size guide block  58 . Of course, with different sizes of knobs  56 , each different sized guide block  58  would have a different cavity  62  to accommodate the different sized knob  56 .  
         [0046]    Further, rather than provide a range of sizes of guide blocks  58 , two or more guide blocks  58  may be provided each of which has a front surface  60  of a different rate of curvature or arc. This may also provide accommodation to different sizes of olecranons. Even further, it is also contemplated that various combinations of different sizes of guide blocks and/or different rates of curvatures, and/or number of spikes may be used.  
         [0047]    Referring back to FIG. 1, the resection spool/mock trochlea retention and adjustment assembly  26  of the resection guide  20  will be discussed. The resection spool/mock trochlea retention and adjustment assembly  26  is configured, adapted and/or operative to releasably retain a spool/mock trochlea  100  (the details of which are discussed below) in a trochlear notch of the ulna when the bone resection guide  20  is installed. The resection spool/mock trochlea retention and adjustment assembly  26  generally includes a spool peg  66 , and a resection template mounting screw  78 . The resection template mounting screw  78  extends through the spool peg  66  as described further below. The spool peg  66  is adjustable with respect to the guide frame  30 , particularly with respect to the second leg  34 . With additional reference to FIG. 6, the spool peg  66  is shown. The spool peg  66  includes threads  70  on a portion thereof, and a non-threaded portion  68  adjacent the threads  70 . The spool peg  66  also has an internal bore  72  that extends axially or longitudinally therethrough. With additional reference to FIG. 7, the resection template mounting screw  78  is shown. The resection template mounting screw  78  includes a non-threaded shaft  80  having a knob  82  on one end thereof and a threaded portion  84  on another end thereof. The rounded outside edge of the knob  82  is preferably knurled to provide gripping power during use and/or setup of the subject bone resection guide  20 . The diameter of the shaft  80  and threaded portion  84  is less than the diameter of the axial bore  72  of the spool peg  66  in order for the threaded portion  84  and the shaft  80  of the resection template mounting screw  78  to extend therethrough.  
         [0048]    As shown in FIG. 1, the threaded portion  70  of the spool peg  66  is thus threadedly received in the threaded bore  42  of the eyelet  40 . As such, the spool peg  66  is axially adjustable about the length of the threads  70  of the stem with respect to the eyelet  40  and a nut  76  movably, threadedly retained on the threaded portion  70 . Therefore, in one direction of rotation of the spool peg  66 , the spool peg  66  axially advances or moves essentially perpendicularly toward an ulna (to the left in FIG. 1) and in another direction of rotation of the spool peg  66 , the spool peg  66  axially advances or moves perpendicularly away from the ulna (to the left). Such translation of the spool peg  66  is represented by the arrow  92  in FIG. 8. Since the resection template mounting screw  78  is coupled carried by the spool peg  66 , the resection template mounting screw  78  also advances perpendicularly towards or away from the ulna when the spool peg  66  is rotated in one direction and rotated in another direction. Again, such translation of the resection template mounting screw  78  is represented by the arrow  96  in FIG. 8. The resection spool/mock trochlea retention and adjustment assembly  26  particularly is configured, adapted and/or operative to advance toward or away from the trochlear notch of the ulna in order to receive and releasably retain a spool or mock trochlea  100  of which is described below. The resection template mounting screw  78  is axially free within the bore  72  of the spool peg  68 .  
         [0049]    An end nut  74  is fixed on the threads  70  at the end of the spool peg  66 . The fixed end nut  74  provides a stop for axial movement of the spool peg  66  through rotation that causes movement towards the ulna. Movement in the opposite direction via opposite rotation allows the resection spool/mock trochlea retention and adjustment assembly  26  to be removed from the eyelet  40  and thus the guide frame  30 . An adjustment nut  76  is provided on the threaded portion  70  of the spool peg  66  between the eyelet  40  and the end nut  74 . The adjustment nut  76  is freely movable between the eyelet  40  and the end nut  74  as indicated by the arrow  94  in FIG. 8. The adjustment nut  76  provides a limiting of the axial travel of the spool peg  66 , through rotation thereof in cooperation with the threaded bore  42  of the eyelet  40 , axially towards the ulna. In other words, the adjustment nut  76  adjustably limits the axial travel of the spool peg  66  in the axial direction towards the ulna. When the adjustment nut  76  is flush or immediately adjacent the end nut  74  the spool peg  66  is allowed to axially travel the greatest distance toward the ulna (maximum travel mode). When the adjustment nut  76  is at the end of the threaded portion  70  distal the end nut  74 , the spool peg  66  is allowed to axially travel the least distance toward the ulna (least travel mode). In all cases, the spool peg  66  provides a seating means for and alignment of a spool or mock trochlea within the trochlear notch of the ulna.  
         [0050]    Referring to FIGS. 9 and 10, there is depicted an exemplary spool, bobbin, mock trochlea, or the like generally designated  100  (and hereinafter, collectively “spool”). The spool  100  is defined by a saddle-shaped body  102  having a first end  104  and a second end  106 . It should be appreciated that the nomenclature “first” and “second” are arbitrary and thus may be interchanged without consequence. The body  102  is shaped to simulate the trochlea of the humerus. As such, in accordance with an aspect of the subject invention, the spool  100  is provided in various sizes, preferably in useful increments or incremental sizes. Since each spool is identical except for size, hereinafter, the characteristics of the spool  100  is intended to cover each and every spool.  
         [0051]    The spool  100  has a first bore  108  extending axially into the body  102  from the first end  104 . The first bore  108  is sized to receive the non-threaded portion  68  of the spool peg (see, e.g. FIGS. 11 and 12). The first bore  108  extends substantially mid or half-way axially into the body  102 . A second bore  110  extends axially into the body  102  from the second end  106 . The second bore  110  extends substantially mid or half-way axially into the body  102 . As best seen in FIG. 10, the second bore  110  has a flat  112  that axially extends the distance of the second bore  110 . The flat  112  essentially creates a “D” shaped profile for the second bore  110 . As described below, the second bore  110  is configured, adapted, and/or operative to receive an orientation rod of a resection template. The first and second bores  108  and  110  are in axial communication with each other.  
         [0052]    The spool  100  also includes a skewed bore  114  defining an opening  116  on one side of the body  102  and an opening  118  on another side of the body  102 . The bore  114  essentially defines a chord as best depicted in FIG. 10. The bore  114  is sized to receive a spool retention rod therethrough. As described below, the spool retention rod allows the spool  100  to be temporarily fixed in the trochlear notch of the ulna. The rod also aligns the axis of the spool at  10  degrees from the long axis of the ulna (this is the angle the prosthesis is designed at) when the rod is oriented parallel to the long axis of the ulna.  
         [0053]    Referring to FIGS. 11 and 12, a spool  100  of an appropriate size of one of the various-dimensioned (sizes and/or shapes) spools  100  is shown situated on the spool peg  66 . It should be appreciated that the resection guide assembly  20  is typically not attached to the spool  100  without the appropriately size-chosen spool  100  being previously situated in the trochlear notch of a patient&#39;s ulna. The spool  100 , however, is shown mounted onto the spool peg  66  for purposes of illustration of the manner in which the resection guide assembly  20  and the spools join.  
         [0054]    Referring particularly to FIG. 12, a spool  100  is shown in sectional view mounted on the spool peg  66 . Stated another way, the spool peg  66  of the resection guide assembly  20  is shown in engagement with the spool  100  after the appropriately-sized spool has been chosen and is situated in the trochlear notch of the patient&#39;s ulna in preparation for resection of the ulna in preparation for prosthetic implantation. When the appropriate sized spool placed in the proper location within the ulnar trochlear notch, the axis of the spool substantially estimates the rotation axis of the ulna. The end of the non-threaded portion  68  of the spool peg  66  is received in the first bore  108 . The threaded end or tip  84  of the resection template mounting or retention screw  78  extends from the end of the spool peg  66  into the second bore  110 . The threaded end  84  is ready to receive and releasably retain a resection template.  
         [0055]    Referring now to FIGS.  13 - 15 , an exemplary resection template, generally designated  120 , is shown. The exemplary resection template  120  includes a substantially flat plate  122  with a first transverse wall  160  on one edge of the plate  122  and a second transverse wall  166  on another edge of the plate  122 . The first and second transverse walls  160  and  166  have a common edge. The first transverse wall  160  has a slot  162  formed therein that has an opening  164  on one end of the first transverse wall  160 . The slot  162  provides a guide for a cutting instrument (such as a bone saw) for resection of ulna bone. The cutting instrument enters the slot  162  via the opening  164 , while the slot  162  provides a guide for the cutting instrument and hence resection. The second transverse wall  166  has a slot  168  formed therein that has an opening  170  on one end of the second transverse wall  166 . The slot  168  provides a guide for a cutting instrument (such as a bone saw) for resection of ulna bone. The cutting instrument enters the slot  168  via the opening  170 , while the slot  168  provides a guide for the cutting instrument and hence resection.  
         [0056]    The resection guide  120  further has a mounting rod  124  extending from a side thereof. The mounting rod  124  includes a flat  126  that defines a “D” cross-section to the rod  124 . The D-shaped mounting rod  124  thus corresponds in shape with the D-shaped bore  110  of the spool. This provides a specific orientation for the resection template with respect to the spool  100 . The rod  124  also includes a threaded bore  128  that is sized to threadedly receive the threaded end  84  of the resection template mounting screw  78 . According to an aspect of the subject invention, various dimensions (sizes and/or shapes) of resection templates are provided in order to accommodate various sizes of ulnas to be resected and/or various implant sizes.  
         [0057]    Referring to FIG. 16, a resection template  120  of an appropriate size of one of the various-sized resection templates  120  is shown situated on the spool  100  and the threaded end  84  of the resection template mounting screw  78 . Particularly, the shaft  124  of the resection template  120  is within the bore  110 , while the threaded end  84  of the resection template mounting screw  78 , via rotation of the knurled knob  82  is threadedly engaged or received in the threaded bore  128  of the shaft  124 . It should be appreciated that the resection template  120  is typically not received in the spool  100  without the appropriately size-chosen spool  100  being previously situated in the trochlear notch of a patient&#39;s ulna, the resection guide  20  attached thereto, and a spool retention rod extending through the bore  114  and into the ulna. The resection template  120 , however, is shown mounted onto the spool  100  for purposes of illustration of the manner in which the resection template  120  and the spool  100  join.  
         [0058]    Use of the Subject Invention  
         [0059]    A use and/or application of the subject invention will now be described. It should be appreciated, however, that the below-described use/application of the subject invention is only exemplary of one manner of use. Other manners of use not specifically described herein are contemplated. Referring to FIG. 17, there is depicted a section of an ulna  130  particularly the end of the ulna  130  with the olecranon  132  and the trochlear notch  138  (i.e. the elbow). The ulna  130  will be resected for prosthetic implant. It should initially be appreciated that the procedure described herein with respect to FIGS.  17 - 19  are not necessary for use of the subject resection guide, but are optional.  
         [0060]    In FIG. 17, the ulna is initially prepared by reaming a bore  136  in the medullary canal  137  of the ulna by a reamer  134 . Thereafter, as depicted in FIG. 18, an intramedullary rod  140  is placed in the reamed bore  136 . Once the intramedullary rod  140  is in place, a grasper  142  is attached to the intramedullary rod  140  as depicted in FIG. 19. At this point soft tissue balance may be determined, and an estimation of the optimum axis of rotation can be made.  
         [0061]    Further, and in preparation of resection of a portion or more of the olecranon  132 , an appropriate dimensioned spool or mock trochlea  100  is selected and placed in the olecranon  132 . Thereafter, and with reference to FIG. 20, the bone resection guide assembly  20  is shown in an appropriate position. Particularly, the resection guide assembly is appropriately adjusted with the block  58  bearing against the olecranon  132 , the spool  100  is retained by the guide assembly  26 , a trocar-tipped pin  160  is retaining the spool  100 , and an appropriate resection template  120  is placed on the spool  100 . The trocar-tipped pin  160  preferably extends into the ulna  130 .  
         [0062]    Once the resection guide  20 , the appropriate spool  100 , and an appropriate resection template  120  is appropriately situated, a bone cutting instrument such as a bone saw (not shown) is used to cut ulna bone. Particularly, the cutting instrument uses the slots  162  and  168  to resect an appropriate portion of the ulna. This provides a properly resected ulna for the particular prosthesis.  
         [0063]    There are a plurality of advantages of the subject invention arising from the various features of the resection guide assembly described herein. It will be noted that alternative embodiments of the resection guide assembly of the subject invention may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of a resection guide assembly that incorporate one or more of the features of the subject invention and fall within the sprit and scope of the subject invention.