Patent Publication Number: US-11660212-B2

Title: Method and apparatus for implanting a knee prosthesis

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 13/153,983 filed on Jun. 6, 2011, the entire disclosure of which is incorporated herein by reference 
     FIELD 
     The present disclosure relates generally to instruments for preparing a tibia and femur for knee joint prostheses and more particularly to instruments and related methods for using the instruments to prepare a tibia and femur for receipt of a revision knee joint prosthesis. 
    
    
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     A knee joint prosthesis typically comprises a femoral component and a tibial component. The femoral component and the tibial component can be designed to be surgically attached to the distal end of the femur and the proximal end of a tibia, respectively. The femoral component can further be designed to cooperate with the tibial component in simulating the articulating motion of an anatomical knee joint. Such knee joint prostheses are generally referred to as primary knee prostheses. 
     Knee joint prostheses, in combination with ligaments and muscles, attempt to duplicate natural knee motion, as well as absorb and control forces generated during the range of flexion. In some instances, however, it may be necessary to replace an existing prosthesis. Such replacement prostheses are generally referred to as revision knee prostheses. Depending on the degree of damage or wear of the primary knee prosthesis, knee tendons and ligaments, however, it may be necessary for a revision knee joint prosthesis to eliminate one or more of these motions in order to provide adequate stability. In this regard, it may be desirable to provide a cruciate retaining (CR) revision knee, a fully constrained revision knee, a posterior stabilized (PS) revision knee or a hinged revision knee for example. Furthermore, in some instances, it may be necessary to account for bone loss in areas adjacent to such knee joint prostheses. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     A method for preparing a femur for receiving a prosthesis can include positioning an intramedullary (IM) member in the femur. A femoral trial component can be positioned onto a distal end of the femur. The femoral trial component can have an attachment portion, an articulating surace and at least two cut surfaces thereon. A modular boss assembly can be attached to the attachment portion of the femoral trial component. The modular boss assembly can have a boss stem that is configured to operably connect to the IM member. A desired contact between the femoral trial component and the distal femur can be confirmed based on the attaching. The femoral trial component can be fixed to the distal femur based on the confirming. The modular boss assembly can be removed from the femoral trial component. A reamer bushing can be coupled relative to the femoral trial component. A cavity can be reamed into the femur using the reamer bushing as a guide. At least one of a modular femoral box trial and a stem adapter can be coupled relative to the femoral trial component. All of the steps including removing the modular boss assembly, coupling the reamer bushing, reaming the cavity and coupling the modular femoral box trial and stem adapter are performed while the femoral trial component remains fixed to the distal femur. 
     According to additional features, attaching the modular boss assembly can include selecting the modular boss assembly from a plurality of modular boss assemblies each having a boss stem that extends along a distinct offset axis. Coupling the reamer bushing can comprise selecting a reamer bushing from a plurality of reamer bushings each having a throughbore that is offset a distance that corresponds to the offset axes of the boss stems. The reamer bushing can be selected based on the selected modular boss assembly. Attaching the modular boss assembly can comprise locating a distal connection plate of the modular boss assembly onto a recessed portion of the femoral trial component. Fasteners can be advanced through passages defined through the distal connection plate and into threadable engagement with the femoral trial component and the attachment portion. According to other features, attaching the modular boss assembly can further comprise rotating the boss stem around a long axis defined through the distal connection plate until a desired orientation is attained relative to the IM member. Posterior stabilized (PS) box cuts can be prepared on the femur using the cut guide surfaces of the femoral trial component. Medial and/or lateral cuts can be prepared through a corresponding one of medial and lateral cut slots defined in the femoral trial component for receipt of a distal femoral augment. According to one example, coupling the reamer bushing can include attaching a positioning ring to the attachment portion, inserting a reduced diameter portion of the reamer bushing into the positioning ring, rotating the reamer bushing about its longitudinal axis until the throughbore is aligned at a desired location, and fixing the reamer bushing from further rotating. 
     According to still other features, attaching the positioning ring can include advancing fasteners through passages defined through the positioning ring into threadable engagement with the femoral trial component at the attachment portion. Fixing the reamer bushing from further rotating can include advancing a peg associated with the positioning ring into a corresponding locating bore defined in the reduced diameter portion of the reamer bushing. The modular femoral box trial can be coupled to the first attachment portion of the femoral trial component. A stem adapter can be coupled to the modular femoral box trial. The stem adapter can have an offset that corresponds to an offset of the modular boss stem. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
       The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG.  1    is a perspective view of various instruments used for preparing a tibia for receipt of a tibial prosthesis according to various examples of the present teachings; 
         FIG.  2    is a perspective view of a tibial spacer assembly according to the present teachings; 
         FIG.  3    is a perspective view of one of the tibial spacers of the tibial spacer assembly in  FIG.  2    located atop a resected proximal end of a tibia to assist in determining a joint line; 
         FIG.  4    is a perspective view of an intramedullary (IM) reamer stop slidably coupled to a reamer; 
         FIG.  5    is a detailed perspective view of the reamer stop of  FIG.  4   ; 
         FIG.  6    is a perspective view of the IM reamer stop engaging a proximal tibia while the reamer is preparing the IM canal of the tibia; 
         FIG.  7    is a perspective view of an IM tibial resection guide cooperating with the reamer shaft; 
         FIG.  8    is a perspective view of a resection block pinned to the tibia while a saw locates through one of the slots in the resection block while a horizontal cut is made in the tibia for receipt of a medial tibial augment; 
         FIG.  9    is an anterior view of the tibia of  FIG.  8    subsequent to the horizontal cut and a vertical cut made on the proximal tibia for receipt of the medial tibial augment; 
         FIG.  10    is an anterior perspective view of the tibial template and offset coin of the instruments illustrated in  FIG.  1    shown with the tibial template resting atop the tibial plateau while the offset coin is rotated relative to a locating stem with a positioning tool to determine the tibial offset; 
         FIG.  11    is an anterior perspective view of the tibial template and offset coin subsequent to determining the preferred offset and removing of the positioning tool and with pins located through apertures of the tibial template to secure the tibial template to the proximal tibia; 
         FIG.  12    is a plan view of the tibial template and offset coin of  FIG.  10    and shown with a series of spring loaded spherical members locating into a circumferential groove of the offset coin according to one example of the present teachings; 
         FIG.  13    is a cross-sectional view taken along lines  13 - 13  of  FIG.  12   ; 
         FIG.  14    is a cross-sectional view taken along line  14 - 14  of  FIG.  13    and shown with a stem adapter and locating stem coupled to the offset coin; 
         FIG.  15    is a cross-sectional view of the tibial template, stem adapter and locating stem of  FIG.  14    and shown with the offset coin exploded; 
         FIG.  16    is an anterior perspective view of the tibial template pinned to the proximal tibia in the desired location and with the offset coin being removed from the stem adapter with a removal tool; 
         FIG.  17    is an anterior perspective view of the tibial template shown with an offset reamer bushing being aligned for receipt into alocating bore of the tibial template; 
         FIG.  18    is a plan view of the offset reamer bushing positioned into the locating bore at an orientation that corresponds with the radial offset of the selected offset coin and rotational orientation that corresponds to the indicia noted on the offset coin; 
         FIG.  19    is a cross-sectional view taken along lines  19 - 19  of  FIG.  18    and illustrating the spring loaded member locating into a circumferential groove of the offset reamer bushing; 
         FIG.  20    is an anterior perspective view of the tibial template shown with an offset reamer of the instruments illustrated in  FIG.  1    and located through the offset reamer bushing to prepare an offset cavity into the tibia for accommodating an implant boss and an offset adapter; 
         FIG.  21    is an anterior view of the tibial template, offset reamer bushing and offset reamer of  FIG.  20   ; 
         FIG.  22    is an anterior view of the tibia shown in  FIG.  1    subsequent to preparation of the offset cavity and removal of the instruments and with an exemplary tibial component, offset adapter and tibial stem implanted with respect to the prepared tibia; 
         FIG.  23    is an anterior perspective view of the tibial template shown with a cruciate augment punch according to additional features; 
         FIG.  24    illustrates a tibia that has been prepared with the cruciate augment punch of  FIG.  23    for receipt of a winged augment and shown with the winged augment coupled between a tibial tray and tibial stem in an implanted position; 
         FIG.  25    is an anterior perspective view of a tibial augment resection block coupled to an anterior portion of a trial tibial tray shown with a trial tibial bearing attached to the trial tibial tray; 
         FIG.  26    is an anterior perspective view of the tibial augment resection block alternatively coupled to the tibial template according to other features; 
         FIG.  27    is an anterior perspective view of the trial tibial tray and trial tibial bearing of  FIG.  25    and illustrated with a bearing removal tool located into a passage of the trial tibial bearing during coupling and decoupling of the trial tibial bearing to the trial tibial tray; 
         FIG.  28    is a cross-sectional view taken along lines  28 - 28  of  FIG.  27    and shown with an actuator of the bearing removal tool being translated to displace an engagement tab to decouple the trial tibial bearing from the trial tibial tray; 
         FIG.  29    is an anterior perspective view of the trial tibial bearing being removed from the trial tibial tray with the bearing removal tool; 
         FIG.  30    is an anterior perspective view of the trial tibial tray shown with an alternate tibial bearing according to additional features; 
         FIG.  31    is a perspective view of various instruments for preparing a distal femur according to the present teachings; 
         FIG.  32    is an anterior perspective view of a reamer stop positioned on a resected distal femur and shown with a reamer shaft extending into an IM canal of the femur; 
         FIG.  33    is a perspective view of a femoral cut guide positioning assembly according to the present teachings; 
         FIG.  34    is an anterior perspective view of the femoral cut guide positioning assembly located onto a distal femur and positioned relative to the reamer shaft; 
         FIG.  35    is an anterior perspective view of a distal cut block of the femoral cut guide positioning assembly pinned to a distal femur and shown with a saw preparing a horizontal cut for accommodating a medial augment; 
         FIG.  36 A  is an anterior view of the femur of  FIG.  35    and shown subsequent to a vertical cut being made for receipt of a medial augment; 
         FIG.  36 B  is a perspective view of a set of femoral spacers according to the present teachings; 
         FIG.  36 C  is an anterior view of the femur of  FIG.  36 A  showing two of the femoral spacers used to determine an augment thickness; 
         FIG.  36 D  is a perspective view of a series of resorbable augment trial spacers according to additional features; 
         FIG.  37    is a perspective view of a femoral cut block shown with a femoral offset coin assembly, stem adapter and locating stem according to the present teachings; 
         FIG.  38    is an anterior perspective view of the femoral cut block shown with the positioning tool rotating an offset coin of the femoral offset coin assembly while the locating stem and stem adapter are positioned in the IM canal of the femur; 
         FIG.  39    is an inferior view of the femoral cut block positioned on the distal femur while the offset coin is rotated until the femoral cut block slidably locates along the distal femur until a desired location is attained; 
         FIG.  40    is an inferior view of the femoral cut block and offset coin assembly of  FIG.  39    and shown with the femoral cut block positioned in the desired location; 
         FIG.  41    is a cross-sectional view of the femoral cut block and offset coin assembly taken along lines  41 - 41  of  FIG.  39   ; 
         FIG.  42    is a cross-sectional view of the femoral cut block and offset coin assembly taken along lines  42 - 42  of  FIG.  40   ; 
         FIG.  43    is an anterior perspective view of the femoral cut block shown with the removal tool removing the offset coin assembly, stem adapter and locating stem subsequent to pinning the femoral cut block at the desired location; 
         FIG.  44    is an anterior perspective view of the femoral cut block shown with a femoral cut block insert located into the locating bore of the femoral cut block and with a saw preparing the distal cuts in the femur; 
         FIG.  45    is an anterior perspective view of a femoral cut-through trial positioned onto the prepared distal femur; 
         FIG.  46    is an anterior perspective view of the femoral cut-through trial shown with the locating stem extending from the IM canal and with a series of modular boss assemblies having various offsets that can selectively and alternatively connect to the locating stem; 
         FIG.  47    is a medial view of the tibia and femur shown with a modular boss assembly connected to the femoral cut-through trial and with a spacer positioned atop the tibial plateau to verify a desired joint line; 
         FIG.  48    is an anterior perspective view of the femur and shown with a positioning ring coupled to the femoral cut-through trial for receipt of a corresponding femoral reamer bushing; 
         FIG.  49    is an inferior view of the femoral cut-through trial, positioning ring and selected femoral reamer bushings of  FIG.  48   ; 
         FIG.  50    is a cross-sectional view of the positioning ring and reamer bushing taken along lines  50 - 50  of  FIG.  49   ; 
         FIG.  51    is an anterior perspective view of the distal femur and shown with a femoral offset reamer located through the femoral reamer bushing and preparing a cavity in the femur for receipt of a femoral offset adapter; 
         FIG.  52    is an anterior view of the distal femur shown with the femoral cut-through trial, positioning ring, femoral reamer bushing and femoral offset reamer of  FIG.  51   ; 
         FIG.  53    is an anterior perspective view of the distal femur shown with the femoral cut-through trial with various trial offset adapters and modular boxes; and 
         FIG.  54    is an anterior view of the distal femur shown with an exemplary femoral component, offset adapter and femoral stem implanted into the prepared distal femur. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. While the following discussion is directed toward instruments and related methods for performing revision surgery, the same may be used as part of a primary knee replacement procedure. 
     With initial reference to  FIG.  1   , a system or kit of tools or instruments for tibial preparation are shown and generally identified at reference numeral  10 . In general, the kit of tools  10  can comprise a tibial resection guide  12 , a resection block  14 , a reamer  16 , and an intramedullary (IM) reamer stop  18 . The kit of tools  10  can further comprise a tibial template  20 , a series of positioning coins or offset adaptors collectively referred to at reference numeral  22 , a locating stem  24 , a stem adapter  26 , a pair of reamers collectively referred to at reference numeral  28 , a series of reamer sleeves collectively referred to at reference numeral  30  and a pair of pins collectively referred to at reference numeral  32 . In general, the tibial resection guide  12  and resection block  14  can be located relative to the reamer  16  for preparing various horizontal cuts, such as medial and lateral cuts on the proximal tibia as will be described herein. The positioning coins  22 , individually identified at reference numerals  22   a ,  22   b ,  22   c  and  22   d , each have bores  42   a ,  42   b ,  42   c  and  42   d , respectively. The positioning coins  22   a ,  22   b ,  22   c  and  22   d  can be selectively and intraoperatively coupled to the stem adapter  26  and locating stem  24  and rotated within a locating bore  36  of the tibial template  20  to determine a desired tibial offset as will be described. 
     The reamer sleeves  30 , individually identified at reference numerals  30   a ,  30   b ,  30   c  and  30   d , can each have throughbores  44   a ,  44   b ,  44   c  and  44   d  that have centers that correspond to, or are concentric with, the respective bores  42   a ,  42   b ,  42   c  and  42   d  of the positioning coins  22 . The reamer sleeves  30  can also be positioned into the locating bore  36  of the tibial template  20  at a rotational orientation that matches the orientation determined with the positioning coins  22 . The reamer sleeves  30  can then be used to guide the appropriate reamers  28  when preparing a cavity in the proximal tibia for receipt of a tibial implant. 
     Turning now to  FIGS.  2  and  3   , a tibial spacer assembly  50  is shown. In the depicted example, tibial spacers  50   a ,  50   b ,  50   c ,  50   d ,  50   e ,  50   f ,  50   g  and  50   h  are provided. The tibial spacer  50   a  has a thickness of 10 mm. According to the example shown, the tibial template  20  can also have a thickness of 10 mm such that the tibial spacer  50   a  or the tibial template  20  can alternatively be used when determining a desired thickness of a tibial bearing. The remaining tibial spacers  50   b - 50   h  each have a thickness of 2 mm. The tibial spacer assembly  50  can be stacked, as needed, to achieve a desired height. The thickness of a given stack of tibial spacers  50   a - 50   h  (or just the tibial spacer  50   a  used alone) represents a desired thickness of a tibial bearing that will be implanted at the proximal tibia. In the examples shown, the tibial spacer  50   b  can be stacked onto the tibial spacer  50   a  to collectively define a thickness of 12 mm. 
     As can be appreciated, the tibial spacers  50   a - 50   h  can be sequentially stacked to achieve additional increments of 2 mm. The tibial spacer  50   c  represents (e.g., the cumulative thickness of the tibial spacer  50   c , the tibial spacer  50   b  and the tibial spacer  50   a ) a thickness of 14 mm. The tibial spacer  50   d  represents a thickness of 18 mm. The tibial spacer  50   f  represents a thickness of 20 mm. The spacer  50   g  represents a thickness of 22 mm. The spacer  50   h  represents a thickness of 24 mm. In other embodiments, other thicknesses of the tibial spacer assembly  50  and the individual spacers  50   a - 50   h  are contemplated. As shown, the respective spacers  50   a - 50   h  can each include a tibial plateau portion, collectively referred to by reference numeral  52 , and a handle portion, collectively referred to by reference numeral  54 . Each of the tibial spacers  50   a - 50   h  can be rotatably connected at terminal ends by way of a fastener  56 . The respective tibial spacers  50   a - 50   h  can each pivotally rotate about the fastener  56  in order to isolate a desired tibial spacer  50   a - 50   h  from the remainder of the spacers  50   a - 50   h . It can be appreciated that while the respective tibial spacers  50   a - 50   h  are shown attached to each other through a fastener  56 , they may alternatively be unattached, separate pieces. 
     The tibial spacer assembly  50  can be used to find the joint line of a tibia T using anatomical landmarks. More specifically, the tibial plateau portion  52  of a given tibial spacer  50   a - 50   h  can be placed atop the tibial plateau of the tibia T or atop the resected proximal end of the tibia. In other words, the primary tibia is removed and the selected spacer  50   a - 50   h  can be positioned on the previously resected proximal tibia. In the depicted embodiment, the spacers  50   a - 50   h  are universal and can accommodate a left or a right tibia. The appropriate joint line will be confirmed when the proper thickness spacer  50   a - 50   h  is placed on the tibial plateau and presents a desired height (i.e., superiorly from the tibial plateau) relative to anatomical landmarks. At this time, a thickness of optional, supplemental augments, such as those disclosed in currently pending and commonly owned U.S. patent application Ser. No. 12/248,517, filed Oct. 9, 2008, incorporated by reference herein in its entirety, can be determined. It can be appreciated that it may be necessary to provide supplemental augments on any combination of the medial and lateral sides of the tibia T. The joint line, or where the tibia T and femur F ( FIG.  34   ) meet, is known once the desired thickness of the identified spacer  50   a - 50   h  and the augmentation need is confirmed and noted. In some examples, the host femur or femoral trial may be located relative to the selected spacer  50   a , etc., to confirm the thickness. The spacer assembly  50  is then removed from the tibia T. 
     With further reference now to  FIGS.  4 - 6   , additional features will be described. Once the joint line has been determined relative to the tibia T, the IM reamer stop  18  can be coupled to the reamer  16 . The reamer  16  can cooperate with the IM reamer stop  18  to prepare the IM canal of the tibia T. During use, the reamer  16  is able to ream a distance into the IM canal until the reamer stop  18  comes into contact with the proximal tibia. 
     The IM reamer stop  18  and the reamer  16  will now be described in greater detail. The IM reamer stop  18  can have a superior surface  60  and an inferior surface  62 . The IM reamer stop  18  can define an opening  64  that extends through the IM reamer stop  18  from the superior surface  60  to the inferior surface  62 . A finger support  66  can be supported on the superior surface  60  of the IM reamer stop  18 . A button  68  can be coupled to a locating finger  70 . The locating finger  70  can be movably fixed to the finger support  66 . In one example, the locating finger  70  can move (e.g., such as by depression of the button  68 ) along an axis that is substantially transverse to an axis defined by the reamer  16 . In one example, a biasing member  74 , such as a spring in the depicted embodiment can bias the locating finger  70  into engagement with the reamer  16 . 
     The reamer  16  can have a reamer shaft  78  that includes a plurality of annular grooves, collectively referred to a reference numeral  80  formed thereon. As can be appreciated, the grooves  80  can provide a nesting location for the locating finger  70  to control the depth of reaming for the reamer  16 . According to one example, the groove  80  can be marked with indicia (not specifically shown) that identify various depths of reaming for the tibia T (as will become appreciated from the following discussion, the reamer  16  and the IM reamer stop  18  can also be used for preparation of the IM canal in the femur). In this regard, the grooves  80  can also correspond to various depths of reaming in the femur as well. 
     For exemplary purposes, the grooves  80  can correspond to 40 mm, 80 mm, 200 mm and other depths of reaming to correspond to a desired stem length. As can be appreciated, the various depths of cut can correspond to various lengths of tibial stems, such as a tibia stem  82  illustrated in  FIG.  22   . It can also be appreciated in some instances it may also be necessary to implant an offset adapter, such as the offset adapter  83  illustrated in  FIG.  22    for example. In those instances where an offset adapter is needed in conjunction with a stem, the grooves  80  will correspond to different lengths of stem. For example, if a 40 mm offset adapter will be used, the groove that corresponds to an 80 mm tibial stem will also correspond to a 40 mm tibial stem with a 40 mm tibial offset adapter. Those skilled in the art can appreciate that the dimensions described herein are merely exemplary. In this regard, grooves can be provided in any combination of configurations along the reamer  16  for identifying a depth of reaming that can accommodate any combination of stems and/or offset adapters as necessary. 
     With specific reference now to  FIG.  6   , use of the reamer  16  and reamer stop  18  relative to a tibia T will be described. In some examples, various reamers  16  having distinct diameters can be used until adequate cortical contact is achieved in the tibia T. Multiple IM reamer stops  18  can be provided, each being operatively connected to a reamer  16  having a distinct diameter. In this way, a surgeon, when switching to a reamer having a larger diameter, can simply remove the combination of reamer  16  and IM reamer stop  18  and utilize another collective set of reamer and IM reamer stop. As can be appreciated, this can minimize the amount of time that may be required to remove a reamer  16  from the opening  64  in an IM reamer stop  18  and replace it with a reamer having another diameter. 
     Once the IM canal of the tibia has been sufficiently prepared, as shown in  FIG.  6   , the IM reamer stop  18  can be removed from the reamer  16 . The reamer  16  can remain in the IM canal. At this point, the reamer  16  can be securely retained in a fixed position by the cortical bone of the tibia T and act as an IM guide. Next, as illustrated in  FIG.  7   , the tibial resection guide  12  can be slid over the reamer  16 . The tibial resection guide  12  can generally comprise a body  84 , an adjustment arm  86 , a block arm  88  and a stylus or finger  90 . The body  84  can include a resection level adjustment knob  92 . The adjustment arm  86  can include a hub  94  that has a passage  96  formed therethrough. The passage  96 , as shown, can slidably receive the reamer shaft  78  of the reamer  16 . The finger  90  can be used to engage the posterior tibia T. A coupler  100  can adjustably secure the adjustment arm  86  through a slot  102  formed through the body  84 . The resection block  14  can then be secured to the block arm  88 . The resection block  14  can define a series of slots  106  on a medial and lateral side. In various embodiments, a trial stem (not shown) may be inserted into the IM canal in order to act as a positioning reference in place of the reamer  16 . 
     The body  84  can be adjusted along the adjustment arm  86  to position the resection block  14  against the tibia T. The resection level adjustment knob  92  can be rotated to place the resection block  14  at a desired level (i.e., relative to a proximal surface of the tibia T). In other words, the resection block  14  can be moved inferiorly/superiorly on the anterior side of the tibia T until the desired location is attained. Once the desired location of the resection block  14  has been achieved, the resection block  14  can be fixed to the tibia T (such as by pins  110 ). The remainder of the IM tibial resection guide  12  along with the reamer  16  can be removed. According to other examples, a medial resection guide  14   a  and/or a lateral resection guide  14   b  can be used in place of the resection block  14 . 
     With reference now to  FIGS.  7 - 9   , an exemplary sequence for preparing the proximal tibia for receipt of a 5 mm medial augment and a 10 mm lateral augment will now be described. It can be appreciated that the medial/lateral cuts can be made to accommodate any tibial augment, such as those disclosed in currently pending and commonly owned U.S. patent application Ser. No. 12/248,517, filed Oct. 9, 2008 which is expressly incorporated herein by reference. The resection level of the tibial resection guide  12  can be set by rotating the resection level adjustment knob  92  to the desired position. In one example, rotation of the resection level adjustment knob  92  can adjust the block arm  88  between a distance of zero and 8 mm along a longitudinal axis of the block arm  88 , which moves the cutting slots  106  in the resection block  14  a certain distance from the top of the stylus or finger  90  in the direction of the longitudinal axis of the block arm  88 . It can be appreciated that the resection level adjustment knob  92  can be configured to adjust the block arm  88  to other distances. It can further be appreciated that other tibial resection guides may be used. Once the resection level is set, a clean-up cut can be made through the proximal most (or 0 mm) slot of the slots  106  on the medial side of the resection block  14 . Similarly, a cut can be made through the second proximal-most (or 5 mm) slot of the slots  106  on the lateral side of the resection block  14 . An exemplary tibia is shown in  FIG.  9    after cutting, subsequent to using the resection block  14 . It will be appreciated that the depths of cut described above are merely exemplary. Those skilled in the art will appreciate that a depth of cut will be made that is consistent with the joint line determined as described above that can accommodate a thickness of a given bearing, such as bearing  114  illustrated in  FIG.  22   . Once the proximal tibia has been prepared using the resection block  14 , the resection block  14  can be removed from the tibia T. Other methods for cutting the tibia for accommodating an augment are discussed herein ( FIGS.  34  and  35   ). In some examples, the tibial spacers  50  (or portions thereof) can be used to fill the void left on the proximal tibia to provide a flat surface for accommodating the tibial template  20 . In other examples, shims or trial augments (such as disclosed in currently pending and commonly owned U.S. patent application Ser. No. 12/248,517 identified above) may be used to fill the void. 
     With reference now to  FIGS.  1  and  10 - 16   , the offset position of the prepared IM canal  120  of the tibia T will be determined using a tibial offset positioning assembly  122 . The tibial offset positioning assembly  122  can generally comprise the tibial template  20 , the positioning coins  22 , the locating stem  24  and the stem adapter  26 . Prior to describing an exemplary method for using the tibial offset positioning assembly  122 , additional features of the tibial template  20 , positioning coins  22 , locating stem  24  and stem adapter  26  will be described in greater detail. The tibial template  20  can generally include a body  124  having an anterior portion  126 , a posterior portion  128 , a medial portion  130  and a lateral portion  132 . In the particular example shown, the medial and lateral portions  130  and  132  are arbitrarily named as the tibial template  20  can be interchangeably used for either a right or a left knee. The tibial template  20  can further include a mark or notch  133  formed thereon. The locating bore  36  can be formed through the body  124  from a superior surface  134  to an inferior surface  136  ( FIG.  1   ). The body  124  can define a pair of radial slot passages  138 . 
     A ledge  140  can be formed on at least a partial circumference of the body  124  at the locating bore  36 . The ledge  140  can further include a first plurality of interface teeth  142 . The body  124  can also define a series of lateral bores  144   a ,  144   b  and  144   c  ( FIG.  12   ) radially extending from a center of the bore  36 . According to one example, the bores  144   a ,  144   b  and  144   c  can be formed from an exterior surface  148  of the body  124  to the locating bore  36 . Each of the bores  144   a ,  144   b  and  144   c  can have a spring biased ball assembly  150   a ,  150   b  and  150   c , respectively therein. Each of the spring biased ball assemblies  150   a ,  15   b  and  150   c  can include a biasing member  152   a ,  152   b  and  152   c  that bias a ball  154   a ,  154   b  and  154   c  in a direction toward the locating bore  36  for cooperating with the respective positioning coins  22  as will be described. According to one example, each of the bores  144   a ,  144   b  and  144   c  can include stops  158   a ,  158   b  and  158   c  therein that capture the respective springs  152   a ,  152   b  and  152   c . According to some examples, the bores  144   a ,  144   b  and  144   c  can be stepped, such that the respective stops  158   a ,  158   b  and  158   c  can be advanced to a location where the stepped bores transition to a reduced diameter. It is further appreciated that the bores  144   a ,  144   b  and  144   c  have a diameter less than the balls  154   a ,  154   b  and  154   c  near the locating bore  36  at a retaining wall (identified at reference  159   a ,  FIG.  13   ) to capture the respective balls  154   a ,  154   b  and  154   c  in the body  124  of the tibial template  20 . Other configurations are contemplated. The anterior portion  126  of the body  124  can include a pair of circumferential recesses  160 . 
     The locating stem  24  can generally include a distal end  166  and a proximal end  168  ( FIG.  14   ). The proximal end  168  can include a hub  170  and a collar  172  formed thereon. The stem adapter  26  can generally include a distal end  174  and a proximal end  176 . The distal end  174  can define a blind bore  178  therein. The proximal end  176  can include a projection portion  180  ( FIG.  15   ). A pair of circumferential grooves  182  can be formed around the projection portion  180 . As will be described herein, the hub  170  of the locating stem  24  can be configured to locate into the blind bore  178  of the stem adapter  26 . Similarly, the projection portion  180  of the stem adapter  26  can be configured to be received by a bore (such as the bore  42   c ) of a positioning coin  22  (such as the positioning coin  22   c ) 
     With specific reference now to  FIG.  1   , the positioning coins  22  will be described in greater detail. In general, the positioning coins  22  can generally provide a disc-like shape and each have a circumferential groove  188  formed therearound. Similarly, each of the positioning coins  22  can include a pair of locating apertures  192 . The locating apertures  192  can each have a first diameter portion  192   a  and a second diameter portion  192   b . The second diameter portion  192   b  can have a diameter less than the first diameter portion  192   a  for interfacing with a removal tool ( FIG.  16   ). Each of the positioning coins  22   b ,  22   c  and  22   d  can also include indicia  194  thereon. The positioning coins  22  can include a neutral positioning coin  22   a  (zero offset), an offset positioning coin  22   b  (2.5 mm offset), an offset positioning coin  22   c  (5 mm offset) and an offset positioning coin  22   d  (7.5 mm offset). The positioning coins  22  can each define the throughbores  42   a ,  42   b ,  42   c  and  42   d , respectively that are offset a distance from a longitudinal axis of the center of the positioning coins  22 , collectively identified at reference numeral  200 . 
     With reference now to  FIGS.  14  and  15   , according to one example, a surgeon can couple the locating stem  24  to the stem adapter  26  by inserting the hub  170  of the locating stem  24  into the blind bore  178  of the stem adapter  26 . At this point, the surgeon can select one of the positioning coins  22  that would appear to have a suitable offset for cooperating with the prepared IM canal  120  ( FIG.  10   ). In the example shown in  FIGS.  10 - 16   , the surgeon has selected the positioning coin  22   c  (having the 5 mm offset). It will be appreciated however that the surgeon may need to intraoperatively switch between the positioning coins  22  until the appropriate offset (recognizing that zero offset may be used with the positioning coin  22   a ) has been selected. According to one example, the projection portion  180  of the stem adapter  26  can be inserted into the bore  42   c  of the positioning coin  22   c . In some examples, an annular projection  184  provided in the bore  42  can create an interference fit with the groove  182  in the stem adapter  26 . An o-ring or other supplemental engaging member may also be positioned between the projection portion  180  and the bore  42   c . The positioning coin  22   c  can then be advanced into the locating bore  36  of the tibial template  20  until the respective balls  154   a ,  154   b  and  154   c  locate into the circumferential groove  188  of the positioning coin  22   c . As can be appreciated, the respective balls  154   a  can initially translate against the bias of the springs  152   a ,  152   b  and  152   c , respectively until the groove  188  aligns for receipt of the respective balls  154   a ,  154   b  and  154   c  ( FIG.  14   ). As can be appreciated, the respective balls  154   a ,  154   b  and  154   c  can be configured to ride along the groove  188  as the positioning coin  22   c  is rotated around the locating bore  36 . 
     At this point, it is important to recognize that only the locating stem  24  is fixed (or substantially fixed) relative to the tibia T. The positioning coin  22   c  is able to rotate around its longitudinal axis  200  causing the tibial template  20  to move around the proximal tibia ( FIG.  10   ). The positioning coin  22   c  can be rotated (e.g., by the surgeon) around its longitudinal axis  200  with a positioning tool  210 . The positioning tool  210  can generally include a handle  212  and a pair of fork members  214 . According to one example, the fork members  214  can be inserted into the first diameter portions  192   a  of the respective locating apertures  192  of the positioning coin  22   c . The positioning coin  22   c  can be rotated (clockwise or counterclockwise) around the axis  200  until a position is attained in which the body  124  achieves optimal coverage over the proximal tibia T centered on cortical bone. Again, in some instances, the surgeon may need to swap out various positioning coins (such as positioning the positioning coins  22   a ,  22   b  and  22   d ) in order to attain the best possible coverage of the proximal tibia. Once the desired position on the proximal tibia is verified, the tibial template  20  can be fixed relative to the tibia T, such as by the pins  32  ( FIG.  11   ). At this point, the surgeon can make a note of the indicia  194  relative to the mark  133  on the superior surface  134  of the tibial template  20 . This will correspond to the tibia offset position or degrees offset. In some instances, it will be appreciated that no offset will be necessary (i.e., optimal coverage can be confirmed with the zero offset positioning coin  22   a ). 
     Once the tibial template  20  has been secured to the proximal tibia T with the pins  32 , the positioning coin  22   c  can be removed from the stem adapter  26 , such as with a removal tool  220 . In one example, the removal tool  220  can have two fork portions  222  that have a first diameter portion  222   a  and a second diameter portion  222   b . The second diameter portion  222   b  can have a diameter less than the first diameter portion  222   a . The first diameter portion  222   a  can be advanced into the first diameter portion  192   a  of apertures  192 . The removal tool  220  can then be rotated around its longitudinal axis, such that the second diameter portions  222   b  of the fork portions  222  locate into the second diameter portions  192   b  of the apertures  192 . In this position, the first diameter portions  222   a  of the fork portions  222  can locate under an edge of the second diameter portion  192   b  or a ledge  226  of the coin  22   c  to transfer a pulling force on the positioning coin  22   c . The stem adapter  26  and locating stem  24  can also be removed at this point. 
     With reference now to  FIGS.  17 - 19   , additional features will be described. One reamer sleeve selected from the group of reamer sleeves collectively referenced by numeral  30  ( FIG.  1   ) can then be located into the locating bore  36  of the tibial template  20 . The collective reamer sleeves  30  can include the neutral reamer sleeve  30   a  (0 mm offset or neutral offset), the offset reamer sleeve  30   b  (2.5 mm offset), the offset reamer sleeve  30   c  (5 mm offset), and the offset reamer sleeve  30   d  (7.5 mm offset). As identified above, the reamer sleeves  30  can each define a throughbore  44   a ,  44   b ,  44   c  and  44   d , respectively. As can be appreciated, each offset corresponds to a radial offset from the center of the sleeve or the longitudinal axis of the tibia T. Each of the reamer sleeves  30  can correspond to a respective positioning coin  22 . In this regard, a surgeon can select an offset reamer sleeve  30  having a similar offset as the positioning coin  22  identified above. The reamer sleeves  30  can each define indicia  230  around its circumferential groove  232  ( FIG.  19   ). A second plurality of interference teeth  234  can be formed around a circumference of the reamer sleeves  30 . The surgeon can then rotationally align the indicia  230  of the reamer sleeve  30   c  to the mark  133  on the tibial template  20 . It is important to recognize that the surgeon rotates ( FIG.  17   ) the reamer sleeve  30   c  (prior to locating the reamer sleeve  30   c  into the locating bore  36  of the tibial template  20 ) in order to align a common indicia  230  of the reamer sleeve  30   c  with the same indicia  194  that was determined by the positioning coin  22   c  ( FIG.  12   ). Once the reamer sleeve  30   c  has been rotated to the desired orientation, the reamer sleeve  30  can be advanced into the locating bore  36 . 
     More specifically, the second plurality of interference teeth  234  can meshingly align with the first plurality of interference teeth  142 . Concurrently, the respective balls  154   a ,  154   b  and  154   c  can locate into the circumferential groove  232  of the reamer sleeve  30   c . As can be appreciated, the meshing engagement between the first plurality of interference teeth  142  and a second plurality of interference teeth  234  can inhibit rotational movement of the reamer sleeve  30   c  around its longitudinal axis. Concurrently, the interaction of the respective balls  154   a ,  154   b  and  154   c  with the circumferential groove  232  of the reamer sleeve  30   c  can inhibit the reamer sleeve  30   c  from coming out (axially) of the locating bore  36 . 
     Turning now to  FIGS.  20  and  21   , once the offset reamer sleeve  30   c  has been advanced to the desired location, the offset reamer  28   a  is inserted through the throughbore  44   c  and an offset cavity  240  is reamed to accommodate an implant boss and an offset adapter (such as the boss  242  and offset adapter  83  shown in  FIG.  22   ). Notably, as illustrated in  FIG.  21   , the offset reamer sleeve  30   c  has an upper plane  244  and a lower plane  246  that are non-parallel. As can be appreciated, the series of offset reamer sleeves  30  can be provided having various upper and lower planes that diverge at various distinct angles. As can be appreciated, each offset reamer sleeve  30  can correspond to an angle of reaming identified at reference  248  relative to the longitudinal axis  249  of the tibia T that will accommodate the profile of any offset adapter as needed (such as disclosed in U.S. patent application Ser. No. 12/248,517, filed Oct. 9, 2008 identified above) as illustrated in  FIG.  22   , the cavity  240  can accommodate the offset adapter  83 . 
     In some examples, the neutral offset reamer sleeve  30   a  can be used in instances where an offset adapter is unnecessary. In such instances, the reamer  28   b  ( FIG.  1   ) can be used to ream an opening in the proximal tibia. 
     In examples where the tibia T must be prepared for receipt of a cruciate augment  250  ( FIG.  24   ), a cruciate augment punch  252  ( FIG.  23   ) can be passed through the locating bore  36  of the tibial template  20 . More specifically, the punch  252  can have a winged plate with cutting teeth  256  that can pass through the slot passages  138  formed on the tibial template  20  while a surgeon grasps the ribbed handle portion  260 . The surgeon can repeatedly axially drive the punch  252  through the locating bore  36  creating the complementary passages in the proximal tibia to receive the winged portions of the augment  250  as shown in  FIG.  24   . 
     With specific reference now to  FIGS.  25 - 30   , additional features of the instant disclosure will be described. Once the tibia T has been reamed for receipt of a tibial implant, trial tibial implants may be used to determine optimal sizes for the replacement tibial component and bearing (such as tibial component  242  and bearing  114 , shown in  FIG.  22   ). Additionally, at this point, it may be desirable to prepare horizontal cuts in the tibia, such as on the lateral and/or medial tibia for receipt of a tibial augment. In this regard, a tibial augment resection block locating tool  270  having a tibial augment resection block  272  can be selectively and alternatively coupled to the tibial template  20  ( FIG.  26   ) or a trial tibial tray  276  ( FIG.  25   ). The tibial augment resection block locating tool  270  can generally comprise a body portion  278  having a distal end  280  and a proximal end  282 . The distal end  280  can generally comprise a distal engaging disc  284 . A handle  286  can be mounted for movement along a longitudinal axis  288  of the body  278  of the tool  270 . According to one example, a user can initially locate the distal engaging disc  284  into one of the circumferential recesses  160  provided on the tibial template  20  ( FIG.  26   ) or alternatively one of the circumferential recesses  160 ′ ( FIG.  25   ) provided on the trial tibial tray  276 . The tibial augment resection block  272  can then be used to make cuts in the tibia, such as medial cuts as shown in  FIGS.  25  and  26    and/or lateral cuts. 
     The trial tibial tray  276  will now be described in greater detail with reference to  FIG.  29   . The trial tibial tray  276  can generally comprise a posterior catch portion  290  that includes a posterior lip  292  and an anterior engagement portion  294  that includes a locking button  296 . The trial tibial tray  276  can be configured to selectively and intraoperatively receive a trial tibial bearing  300 . It can be appreciated that while one trial tibial bearing  300  is shown in the drawings, a series of trial tibial bearings having various sizes and thicknesses will be provided. Similarly, a series of superiorly extending members  302   a  ( FIG.  25   ),  302   b  ( FIGS.  27  and  29   ) and  302   c  ( FIG.  30   ) having various geometries according to one application can be configured to selectively couple to the trial tibial bearing  300  by way of a fastener  304 . 
     According to various features, the trial tibial bearing  300  can be selectively coupled to the trial tibial tray  276  by initially locating a posterior catch  310  ( FIG.  28   ) of the trial tibial bearing  300  under the posterior lip  292  of the posterior catch  290  and subsequently advancing an anterior end  312  toward the trial tibial tray  276 . A lock  316  can initially and temporarily retract into the trial tibial tray  276  against the bias of a spring  320  that is retained within a bore  322  of the trial tibial tray  276  by a disc  324 . 
     As illustrated in  FIGS.  27  and  28   , a bearing removal tool  330  can be provided for selectively removing the trial tibial bearing  300  from the trial tibial tray  276 . In general, the bearing removal tool  330  can include a distal end  334  and a proximal end  336 . An actuator  338  can be slidably mounted on a central body  340  of the bearing removal tool  330 . The actuator  338  can have an engaging portion  342  formed thereon. The distal end  334  can generally comprise a distal tip  344  that can extend at an orthogonal angle relative to a longitudinal axis of the central body  340 . The bearing removal tool  330  can be used to disconnect the trial tibial bearing  300  from the trial tibial tray  276 . In this regard, the distal tip  344  of the bearing removal tool  330  can be initially advanced through a passage  350  ( FIGS.  28  and  30   ) to depress the lock  316  into the bias of the spring  320 . Once the lock  316  has been sufficiently depressed with the distal tip  344  (spring  320 ) of the bearing removal tool  330 , a user can slidably advance the actuator  338  to provide a gripping force onto the trial tibial bearing  300  at the passage  350 . The central body  340  can be fixed relative to the proximal end  336  while the tip  344  moves relative to the central body  340 . Next, the user can lift the trial tibial bearing  300  away from the trial tibial tray  276  (see  FIG.  29   ). At this point, the trial tibial tray and bearing combination having the optimal fit with the tibia can be noted for corresponding with the appropriate tibial implants. The trial tibial tray and bearing can then be trialed with the distal femur F or femoral cut-through-trial  570  ( FIG.  45   ). 
     Turning now to  FIG.  31   , a system or kit of tools for femoral preparation are shown and generally identified at reference numeral  370 . In general, the kit of tools  370  can comprise a femoral template  372 , a series of femoral offset coin assemblies collectively referred to at reference numeral  374 , a femoral cut block insert  376 , pins  378 , the locating stem  24  and the stem adapter  26 . In general, femoral template  372  can be used to determine an optimal position of a femoral component relative to an IM canal of the femur. The femoral template  372  can also act as a cut block for guiding a cutting tool when preparing various cuts on a distal femur once the desired location on the distal femur has been determined. In this regard, the femoral template  372  can generally comprise a body  380  having an anterior portion  382 , a posterior portion  384 , a medial portion  385  and a lateral portion  386 . In the particular example shown, the medial and lateral portions  385  and  386 , respectively, are arbitrarily named as the femoral template  372  can be interchangeably used for either a right or a left knee. The body  380  can further include an inferior surface  390  and a superior surface  392 . A locating bore  394  can be defined through the body  380  from the inferior surface  390  to the superior surface  392 . In general, the locating bore  394  can define an oblong passage through the body  380 . A shelf  396  can be formed on the superior surface  392  of the body  380  that generally projects into the locating bore  394 . The body  380  can also define an anterior cut slot  400 , an anterior chamfer cut slot  402 , a first posterior cut slot  404 , a second posterior cut slot  406  and a posterior chamfer cut slot  408 . A pair of pin passages  410  can be defined through the body  380  generally through the posterior portion  384 . As will become appreciated, the pin passages  410  can be configured to receive the pins  378  to fix the femoral template  372  relative to the distal femur once the desired position has been attained. 
     The femoral offset coin assemblies  374  are individually identified at reference numerals  374   a ,  374   b ,  374   c  and  374   d . Each femoral offset coin assembly  374   a ,  374   b ,  374   c  and  374   d  can comprise a femoral coin housing  420   a ,  420   b ,  420   c  and  420   d  and a corresponding positioning coin  422   a ,  422   b ,  422   c  and  422   d . As will be described herein, the femoral offset coin assemblies  374  can be selectively and intraoperatively secured within the locating bore  394  of the femoral template  372  to determine a desired femoral offset. More specifically, the stem adapter  26  and locating stem  24  can be selectively coupled relative to each of the positioning coins  422   a ,  422   b ,  422   c  and  422   d  while the associated femoral coin housing  420   a ,  420   b ,  420   c  or  420   d  is positioned into the locating bore  374  of the femoral template  372 . 
     The femoral coin housings  420   a ,  420   b ,  420   c  and  420   d  can each respectively include a locating groove  424   a ,  424   b ,  424   c  and  424   d  thereon. The positioning coins  422   a ,  422   b ,  422   c  and  422   d  each have respective bores  428   a ,  428   b ,  428   c  and  428   d  formed therein. The location of the respective bores  428   a ,  428   b ,  428   c  and  428   d  can correspond to various offsets. Each of the bores  428   a ,  428   b ,  428   c  and  428   d  are offset a distance relative to a longitudinal axis or center, collectively identified at reference numeral  430 , of the respective positioning coins. In this regard, the femoral offset coin assemblies  374  can include a zero offset (positioning coin  422   a ), a 2.5 mm offset (positioning coin  422   b ), a 5 mm offset (positioning coin  422   c ) and a 7.5 mm offset (positioning coin  422   d ). 
     Each of the positioning coins  422   a ,  422   b ,  422   c  and  422   d  can include a pair of locating apertures  440 . The locating apertures  440  can each have a first diameter portion  440   a  and a second diameter portion  440   b . The second diameter portion  440   b  can have a diameter that is less than the first diameter portion  440   a  for interfacing with the removal tool  220  ( FIG.  43   ). Each of the positioning coins  422   b ,  422   c  and  422   d  can have an indicia  444  formed thereon. As will be described, the indicia  444  can be referenced relative to a notch collectively identified at reference numeral  446  on the respective femoral coin housings  420   b ,  420   c  and  420   d.    
     With reference now to  FIG.  32   , an exemplary method for preparing a femur F during revision surgery will be described. Again, it can be appreciated that in a revision surgery, it may be necessary to remove a prior implanted femoral component in any suitable manner. At the outset, the IM reamer stop  18  can be coupled to the reamer shaft  78  at the desired location. The reamer  16  can cooperate with the IM reamer stop  18  to prepare the IM canal of the femur F in a similar manner as described above with respect to preparation of the IM canal of the tibia (see  FIGS.  4 - 6   ). The reamer shaft  78  can be driven by a drive device (not specifically shown) at a drive end. Also, as discussed above, the grooves  80  can correspond to various depths of reaming into the femur F. As can be appreciated, the various depths of reaming can correspond to various lengths of femoral stems (such as femoral stem  450 ,  FIG.  54   ). 
     As with the tibia described above, in some examples, it may be necessary to implant an offset adapter (such as offset adapter  452 ,  FIG.  54   ). In those examples where an offset adapter is needed in conjunction with a stem, the grooves  80  will correspond to different lengths of stems. For example, if a 40 mm offset adapter will be used, the groove that corresponds to an 80 mm femoral stem (used alone) will also correspond to a 40 mm femoral stem that will be used in conjunction with a 40 mm femoral offset adapter. Again, the grooves  80  can be provided in any combination of configurations along the reamer shaft  78  for identifying a depth of reaming that can accommodate any combination of stems and/or offset adapters as needed. Furthermore, various reamers having distinct diameters can be used until adequate cortical contact is achieved in the femur F. Moreover, multiple IM reamer stops  18  can be provided, each being operatively connected to a reamer  16  having a distinct diameter. 
     With reference now to  FIG.  33   , a distal revision cut assembly  460  will be described. The distal revision cut assembly  460  can generally comprise a distal revision block  462 , a tower  464 , a distal positioning plate  466 , a first pair of pins  468 , a second pair of pins  470  and magnets  472 . The distal revision block  462  can generally include a series of cut slots  474 , a plurality of pin passages  476  and a pair of recesses  478  for receiving the magnets  472 . The tower  464  can generally include a locating channel  480  and a pair of posts  482 . The distal positioning plate  466  can generally include a pair of bores  486  for selectively receiving the posts  482  of the tower  464 . The distal positioning plate  466  can further define a throughbore  488  for operatively receiving the reamer shaft  78 , as will be described. A pair of passages  490  can be defined in the distal positioning plate  466  for intraoperatively receiving the pins  470 . 
     With specific reference now to  FIG.  34   , the distal revision cut assembly  460  will be described according to one exemplary method of use. Initially, the throughbore  488  of the distal positioning plate  466  can be advanced over the reamer shaft  78  until reaching a position against the distal femur. Next, the distal revision block  462  can be coupled to the tower  464 . In one example, the channel  480  of the tower  464  can locate along the distal revision block  462 , such that the magnets  472  magnetically connect the tower  464  along the distal revision block  462 . At this point, the posts  482  can locate through the bores  486  in the distal positioning plate  466 . It can be appreciated that the sequence of assembly described with respect to  FIG.  34    for the distal revision cut assembly  460  can be altered while still reaching the same result. Once the desired location has been attained, the distal positioning plate  466  can be pinned to the distal femur using the second set of pins  470 . Next, the first set of pins  468  can be located through the passages  476  in a distal revision block  462  to pin the distal revision block  462  to the distal femur. At this point, the reamer  16 , distal positioning plate  466  and tower  464  can be removed leaving only the distal revision block  462  (see  FIG.  35   ). Next, distal cuts can be made on the femur F using any of the cut slots  474  defined through the distal revision block  462  in order to make a distal resection or prepare for distal augments, if necessary (see  FIG.  36 A ). 
       FIG.  36 B  illustrates exemplary femoral spacers  492 . In the depicted example, femoral spacers  492   a ,  492   b ,  492   c  and  492   d  are provided. The femoral spacer  492   a  has a thickness of 10 mm. The remaining femoral spacers  492   b - 492   d  each have a thickness of 5 mm. The femoral spacer assembly  492  can be stacked, as needed, to achieve a desired height. The thickness of a given stack of femoral spacers represents a desired thickness of a femoral prosthetic component. For example, as shown on  FIG.  36 C , the femoral spacers  492   c  and  492   d  are stacked on a distal femur F to determine a thickness of a medial femoral augment. The spacers  492  can also be used to determine a thickness of a lateral femoral augment. 
     The respective spacers  492   a - 492   d  can each include a distal femoral portion, collectively referred to by reference numeral  494 , and a handle portion, collectively referred to by reference numeral  496 . Each of the femoral spacers  492   a - 492   d  can be rotatably connected at terminal ends by way of a fastener  498 . The respective femoral spacers  492   a - 492   d  can each pivotally rotate about a fastener  498  in order to isolate a desired femoral spacer  492   a - 492   d  from the remainder of spacers  492   a - 492   d . Furthermore, the spacers  492  can be used to determine a joint line of the femur F using anatomical landmarks. Specifically, the distal femoral portion  494  of a given femoral spacer  492   a - 492   d  can be placed against the distal femur F. In one example, the primary femur can be removed and the selected spacers  492   a - 492   d  can be positioned on the previously resected femur F. The spacers  492   a - 492   d  can be universal and can accommodate a left of a right femur. The appropriate joint line can be confirmed when the proper thickness spacer  492   a - 492   d  is placed on the distal femur and presents a desired height (i.e. inferiorly from the distal femur) relative to anatomical landmarks. 
     With reference to  FIG.  36 D , a series of augment trial spacers  499   a ,  499   b  and  499   c  are illustrated. In the example shown, the augment trial spacer  499   a  can have a thickness of 5 mm, the augment trial spacer  499   b  can have a thickness of 10 mm and the augment trial spacer  499   c  can have a thickness of 15 mm. The thickness is identified as a dimension in the superior/inferior direction as these augment trial spacers  499   a ,  499   b  and  499   c  can be configured to be located at a location on the distal femur to fill the space of a removed femoral defect (i.e., such as shown in  FIG.  36 A ). The augment trial spacers are made of bioresorbable material, such as Lactosorb®. Because the augment trial spacers  499   a ,  499   b  and  499   c  are formed of bioresorbable material, if needed, a surgeon can simply cut or pierce through the augment trial spacers  499   a ,  499   b  or  499   c  while preparing the bone. It can be appreciated that the augment trial spacers  499   a ,  499   b  and  499   c  can be used in areas that are not only possible for engaging a saw blade but also any of the pins, reamers or other cutting devices discussed herein. In this regard, a surgeon can make cuts, place pins and prepare the bone without worry for dulling the tools or creating debris, which the body cannot easily handle. For example, if a saw blade or pin, such as any disclosed herein, passes through the augment trial spacer and carries some particles or small pieces of the augment trial spacer into the bone, the particles or small pieces will simply be absorbed into the body without causing infection. 
     In some examples, some or all of the outside surfaces of the augment trial spacers  499   a ,  499   b  and  499   c  can have a tacky or sticky surface that can facilitate gripping of the bone or adjacent instrument. The augment trial spacers  499   a ,  499   b  and  499   c  can additionally include score marks  500   a ,  500   b  and  500   c , respectively. The score marks can assist the surgeon in snapping or cutting off unneeded depth (in the anterior/posterior direction) of the augment trial spacers  499   a ,  499   b  and  499   c . As shown in  FIG.  38   , the augment trial spacer  499   a  is shown positioned between the distal femur and femoral template  372 . It can be appreciated that the augment trial spacers  499   a ,  499   b  and  499   c  can additionally or alternatively be used during preparation of the proximal tibia. 
     With reference now to  FIGS.  31  and  37 - 42   , the offset position of a prepared IM canal  501  of the femur F will be determined using a femoral offset positioning assembly  502  ( FIG.  37   ). The femoral offset positioning assembly  502  can generally comprise the femoral template  372 , the femoral offset coin assemblies  374  ( FIG.  31   ), the locating stem  24 , the stem adapter  26  and the pair of pins  378 . Prior to describing an exemplary method for using the femoral offset positioning assembly  502 , additional features of the femoral template  372  will be described with reference to  FIGS.  37 ,  41  and  42   . The body  380  of the femoral template  372  can have a pair of bores  510   a  and  510   b , respectively formed therein. According to one example, the bores  510   a  and  510   b  can be formed from an exterior surface  512  of the body  380  to the locating bore  394 . Both of the bores  510   a  and  510   b  can have a spring biased ball assembly  514   a  and  514   b , respectively therein. Both of the spring biased ball assemblies  514   a  and  514   b  can include biasing members  516   a  and  516   b  that bias balls  518   a  and  518   b , respectively in a direction toward the locating bore  394  for selectively engaging the locating grooves ( 424   a ,  424   b ,  424   c  and  424   d ) of the respectively femoral coin housings  420   a ,  420   b ,  420   c  and  420   d  as will be described. According to one example, both of the bores  510   a  and  510   b  can include stops or set screws  520   a  and  520   b  therein that capture the respective biasing members  516   a  and  516   b . According to some examples, the bores  510   a  and  510   b  can be stepped, such that the respective stops  520   a  and  520   b  can be advanced to a location where the stepped bores transition to a reduced diameter. It can be further appreciated that the bores  510   a  and  510   b  can have a diameter that is less than the balls  518   a  and  518   b  near the locating bore  394  to capture the respective balls  518   a  and  518   b  in the body  380  of the femoral template  372 . 
     As described above, the locating stem  24  can be selectively coupled to the stem adapter  26 . In this regard, the hub  170  of the locating stem  24  can be configured to locate into the blind bore  178  of the stem adapter  26 . Similarly, the projection portion  180  of the stem adapter  26  can be configured to be received by a bore (such as the bore  428   c ) of a positioning coin, such as the positioning coin  422   c . In this regard, the surgeon can select one of the femoral offset coin assemblies  374  that would appear to have a suitable offset for cooperating with the prepared IM canal  501  ( FIG.  38   ). In the examples shown in  FIGS.  37 - 43   , the surgeon has selected the femoral offset coin assembly  474   c  having the positioning coin  422   c  that includes the 5 mm offset. It can be appreciated however that the surgeon may need to intraoperatively switch between the femoral offset coin assemblies  374  until the appropriate offset (recognizing that zero offset may be used with the femoral offset coin assembly  374   a ) has been selected. While not specifically shown, in some examples an annular projection (such as the annular projection  184  identified in  FIG.  15    of the positioning coin  22   c ) can create an interference fit with the groove  182  in the stem adapter  26 . Again, an o-ring or other supplemental engaging member may also be positioned between the projection portion  180  and the bore  428   c . The femoral offset coin assembly  474   c  can then be advanced into the locating bore  394  of the femoral template  372  until the respective balls  518   a  and  518   b  locate into the groove  424   c  of the femoral coin housing  420   c  of the femoral offset coin assembly  374   c . As can be appreciated, the respective balls  518   a  and  518   b  can initially translate against the bias of the springs  516   a  and  516   b , respectively, until the groove  424   c  aligns for receipt of the respective balls  518   a  and  518   b  (see  FIGS.  41  and  42   ). It can also be appreciated that concurrently, the femoral coin housing  420   c  can rest atop the shelf  396  provided on the body  380  at the locating bore  394 . 
     At this point, it is important to recognize that only the locating stem  24  is fixed (or substantially fixed) relative to the femur F. The positioning coin  422   c  is able to rotate around its longitudinal center axis  430  within the femoral coin housing  420   c , causing the femoral template  372  to move around the distal femur (see  FIGS.  38 - 40   ). The positioning coin  422   c  can be rotated (e.g., by the surgeon) around its longitudinal axis  430  with the positioning tool  210 . Similarly, as described above with respect to the tibial offset positioning assembly  122  described above, the fork members  214  can be inserted into the first diameter portions  440   a  of the respective locating apertures  440  of the positioning coin  422   c . The positioning coin  422   c  can be rotated around the axis  430  until a position (degree and/or offset) is attained in which the body  380  achieves optimal coverage or placed over cortical bone of the distal femur F. Again, in some instances, the surgeon may need to swap out various femoral offset coin assemblies  374  in order to attain the best possible coverage of the distal femur. 
     The femoral template  372  can also be used to verify joint space of the knee prior to making the distal cuts. In one example, the femoral template  372  can have a thickness of 9 mm. The femoral template  372  can be positioned on the distal femur while the tibial template  20  is positioned on the proximal tibia. The joint space can be observed with the knee in flexion to determine the optimal position of the femoral template  372 . The tibial spacers  50  ( FIGS.  2  and  3   ) may also be used to account for additional space. Additionally, the femoral spacers  492  may be used. In some examples, the tibial and/or femoral spacers  50 ,  492  can be placed directly against the respective bones (i.e., without either of the tibial template  20  or femoral template  372 ). Because the system of the present teachings allows the surgeon to adjust the offset position of the femoral template  372 , a surgeon can open and close the flexion space by moving the femoral template  372  around the distal femur using the tibial and/or femoral spacers as needed and observing the flexion space in real time. 
     Once the desired position on the distal femur is verified, the femoral template  372  can be fixed relative to the femur F, such as by the pins  378  ( FIG.  43   ). At this point, the surgeon can make a note of the indicia  444  relative to the mark or notch  446  on the femoral coin housing  420   c . This will correspond to the femoral offset position. Again, in some instances, it can be appreciated that no offset may be necessary (i.e., optimal coverage can be confirmed with the femoral offset coin assembly  374   a ). 
     Turning now to  FIG.  43   , once the femoral template  372  has been secured to the distal femur F with the pins  378 , the femoral offset coin assembly  374   c  can be removed from the stem adapter  26 , such as with the removal tool  220 . Similarly, with the tibial offset positioning assembly  122  described above, the first diameter portion  222   a  of the fork portion  222  can be advanced into the first diameter portion  440   a  of the apertures  440 . The removal tool  220  can then rotated around its longitudinal axis, such that the second diameter portions  222   b  of the fork portions  222  locate into the second diameter portions  440   b  of the apertures  440 . In this position, the first diameter portions  222   a  of the fork portions  222  can locate under an edge of the second diameter portions  440   b  a ledge  530  of the positioning coin  422   c  to transfer a pulling force onto the positioning coin  422   c . The stem adapter  26  and the locating stem  24  can also be removed at this point. 
     Turning now to  FIG.  44   , once the femoral template  372  has been securely pinned to the distal femur and the femoral offset coin assembly  374   c  is removed from the locating bore  394 , the femoral cut block insert  376  can be inserted into the locating bore  394 . At this point, the surgeon can make the respective cuts on the distal femur using a cutting instrument  534 . More specifically, the surgeon can use the anterior cut slot  400 , the anterior chamfer cut slot  402 , the first posterior cut slot  404 , the second posterior cut slot  406  and the posterior chamfer cut slot  408  as guides for the cutting instrument  534 . In this regard, the femoral template  372  can be utilized to not only assist in determining an optimal femoral offset to achieve a desired coverage on a distal femur, but also be used as a cutting block to guide the cutting instrument  534  when making the distal cuts on the femur F. Furthermore, the femoral template  372  can be used as a spacer when verifying a joint line. In one example, the femoral template  372  can have a thickness of 10 mm. 
     Once the anterior cut, posterior cut and anterior and posterior chamfer cuts have been made on the distal femur, the femoral template  372  and femoral cut block insert  376  can be removed from the distal femur. At this point, a femoral cut-through-trial  570  can be positioned on the prepared distal femur F ( FIG.  45   ). The femoral cut-through-trial  570  can be used for both femoral trialing and as a guide for cutting portions of the femur F for receipt of femoral augments as will be described. According to one advantage of the present teachings, the femoral cut-through-trial  570  can remain fixed to the distal femur F once the desired coverage and offset (if necessary) has been determined. The femoral cut-through-trial  570  can be used as a trial and includes a representative articulating surface  572  and a bone engaging surface  574 . 
     The bone engaging surface  574  can be collectively formed by an anterior bone engaging surface  576 , an anterior chamfer bone engaging surface  578 , a distal bone engaging surface  580 , a posterior chamfer bone engaging surface  582  and a posterior bone engaging surface  584 . A series of bores  586  can be formed through the femoral cut-through-trial  570  for receiving pins ( 588 ,  FIG.  46   ) to fix the femoral cut-though-trial  570  once the desired position has been attained on the distal femur. A pair of recessed flare portions  590  can be formed into the articulating surface  572 . A threaded bore  592  can be provided at each of the recessed flare portions  590 , respectively. A first and second series of medial cut slots  600  and  602  can be formed through the femoral cut-through-trial  570 . A first and second series of lateral cut slots  604  and  606  can be formed through the femoral cut-through-trial  570 . The first series of medial cut slots  600  can be used to guide the cutting instrument  534  for preparing medial cuts on the distal femur at a location generally parallel to the distal bone engaging surface  580 . 
     The first series of lateral cut slots  604  can be used to guide the cutting instrument  534  for preparing lateral cuts on the distal femur at a location generally parallel to the distal bone engaging surface  580 . As can be appreciated, the first series of medial and lateral cut slots  600  and  604  may be used if it is desired to remove portions of distal, medial and/or lateral femoral bone and replace the removed bone with distal femoral augments. Similarly, the second series of medial and lateral cut slots  602  and  606  can be used to guide a cutting instrument for cutting posterior portions of the distal femur in a location that is generally parallel to the posterior bone engaging surface  584  of the femoral cut-through-trial  570 . In this regard, it may be desirable to remove portions of the medial and/or lateral posterior femur and replace that area with posterior augments that attach to a femoral component. 
     With reference now to  FIG.  46   , a series of modular boss assemblies  610  are shown for selectively and alternatively cooperating with the locating stem  24  and the femoral cut-through-trial  570 . In general, the series of modular boss assemblies are identified individually at reference numerals  610   a ,  610   b ,  610   c  and  610   d . The series of modular boss assemblies  610  can correspond with the femoral offset coin assemblies  374 . In this regard, the modular boss assembly  610   a  can have a boss stem  612   a  that corresponds to a zero offset. The modular boss assembly  610   b  can have a stem  612   b  that corresponds to a 2.5 mm offset. The modular boss assembly  610   c  has a boss stem  612   c  that corresponds to a 5 mm offset. The modular boss assembly  610   d  has a boss stem  612   d  that corresponds to a 7.5 mm offset. 
     The modular boss assembly  610   b  can have an intermediate offset body  614   b . The modular boss assembly  610   c  can have an intermediate offset body  614   c . The modular boss assembly  610   d  can have an intermediate offset body  614   d . The modular boss assemblies  610   a ,  610   b ,  610   c  and  610   d  can each comprise a distal connection plate  618   a ,  618   b ,  618   c  and  618   d  defining a central aperture  620   a ,  620   b ,  620   c  and  620   d  for receiving a connector, such as a connector  623  shown on the modular boss assembly  610   c . The distal connection plates  618   a ,  618   b ,  618   c  and  618   d  can each include a pair of passages  624   a ,  624   b ,  624   c  and  624   d  that are configured to receive fasteners  626   a ,  626   b ,  626   c  and  626   d , respectively. The intermediate offset body  614   b  of the modular boss assembly  610   b  can interconnect the stem  612   b  with the connector  622   b . The intermediate offset body  614   c  of the modular boss assembly  610   c  can interconnect the stem  612   c  with the connector  622   c . The intermediate offset body  614   d  of the modular boss assembly  610   d  can interconnect the stem  612   d  with the connector  622   d . The intermediate offset bodies  614   b ,  614   c  and  614   d  can have a proximal connecting end  630   b ,  630   c  and  630   d , respectively. The intermediate offset bodies  614   b ,  614   c  and  614   d  can also include a distal connecting end  632   b ,  632   c  and  632   d , respectively. Each of the proximal connecting ends  630   b ,  630   c  and  630   d  include a first plurality of interconnecting teeth  634   b  that selectively interlock with a second plurality of teeth  636   b  on the stem  612   b . The first plurality of interconnecting teeth  634   b ,  634   c  and  634   d  of the intermediate offset bodies  614   b ,  614   c  and  614   d  can each be rotated around the second plurality of interconnecting teeth  634   b ,  634   c  and  634   d  in the respective stems. 
     The distal connecting ends  632   b ,  632   c  and  632   d  all include a third plurality of interconnecting teeth  640   b ,  640   c  and  640   d  that selectively engage a fourth plurality of interlocking teeth  642   b ,  642   c  and  642   d  provided on the connectors  622   b ,  622   c  and  622   d , respectively. The third plurality of interconnecting teeth  640   b ,  640   c  and  640   d  of the intermediate offset bodies  614   b ,  614   c  can each be rotated around the fourth plurality of interconnecting teeth  640   b ,  640   c  and  640   d  on the connectors  622   b ,  622   c  and  622   d . As can be appreciated, the intermediate offset bodies  614   b ,  614   c  and  614   d  can each rotate around a longitudinal axis  650  collectively defined through each of the distal connection plates  618   a ,  618   b ,  618   c  and  618   d  in order to position the respective stems  612   b ,  612   c  or  612   d  in a rotational orientation (or at the selected rotation angle or degree) that will align with the IM canal of the femur. Once the desired position on the distal femur F has been attained, the femoral cut-through-trial  570  can be fixed to the distal femur F with the pins  588 . While only two pins  588  are shown, additional pins and/or pins located through other bores  586  may be used. 
     Turning now to  FIG.  47   , additional features of the present teachings will be further described. With the femoral cut-through-trial  570  secured to the distal femur and with the modular boss assembly  610   c  attached at the recessed flare portion  590 , the joint line  652  with respect to the tibia T can be visualized using one of the tibial spacers, such as the tibial spacer  50   a . In this regard, the joint line is represented by the tibial plateau portion  52  of the tibial spacer  50   a , which is determined based on anatomical landmarks. At this time, the distal augmentation needs for the tibia T and femur F can be determined. 
     Moreover, a thickness of a tibial bearing can be verified. 
     With reference now to  FIGS.  48 - 52   , reaming of the femur to accommodate a femoral offset adapter (such as the offset adapter  452 ,  FIG.  54   ) will be described. A femoral offset reaming assembly  656  can include a positioning ring  658  and a series of reamer bushings, collectively referred to at reference numeral  660 . The reamer bushings  660  can include a neutral reamer bushing  660   a  (0 mm offset or “neutral offset”), an offset reamer bushing  660   b  (2.5 mm offset), an offset reamer bushing  660   c  (5 mm offset) and an offset reamer bushing  660   d  (7.5 mm offset). Indicia marks  664  are collectively formed around all of the reamer bushings  660 . Similarly, a plurality of locating bores  668  can be formed around a reduced diameter portion  670  of each of the reamer bushings  660 . Offset bores  672   a ,  672   b ,  672   c  and  672   d  can be formed through each of the reamer bushings  660 , respectively. The offset bores  672   a ,  672   b ,  672   c  and  672   d  can be all formed through the respective reamer bushings  660  at an offset location relative to a longitudinal axis collectively identified at reference numeral  674  of the reamer bushings  660 . It can be appreciated that the offset bore  672   a  of the reamer bushing  660   a  can have a zero offset relative to the longitudinal or center axis  674 . 
     The positioning ring  658  will now be described in greater detail. The positioning ring  658  can generally provide a ring-shaped body  680  that defines an opening  682  therein. A pair of locating portions  686  can have apertures  688  for receiving fasteners  690  that can selectively threadably locate into the threaded bores  592  on the femoral cut-through-trial  570 . A locating peg  694  can extend from a pole handle  696  that extends out of a neck  698  of the ring-like body  680 . As will be described, the peg  694  can selectively locate into one of the locating bores  668  once the desired indicia  664  aligns with a mark  700  on the positioning ring  658  to correspond with the noted indicia  444  that align with the notch  446  of the selected offset coin assembly  374  above. 
     Once the corresponding reamer bushing  660  has been selected that has an offset that matches an offset identified from the selected offset coin assembly  374 , the reamer bushing (such as the reamer bushing  672   c  identified in  FIG.  48   ) can be located into the opening  682  of the positioning ring  658 . Next, the pole handle  696  can be pulled away from the ring-like body  680  and the reamer bushing  660   c  can be rotated around the central axis to align the corresponding indicia  664  with the mark  700  on the positioning ring  658  that corresponds with the noted indicia  440  and notch  446  determined above. At this point, the pole handle  696  can be pushed inwardly toward the ring-like body  680 , such that the peg  694  securely locates into one of the locating bores  668  to preclude further rotation of the reamer bushing  660   c  around the central axis  674 . 
     At this point, a femoral offset reamer  710  can be located into the offset bore  672   c  and the offset cavity can be reamed. As shown in  FIG.  52   , the offset reamer bushing  660   c  has a first plane  714  and a second plane  716  that are non-parallel. As can be appreciated, the series of reamer bushings  660  can be provided having various first and second planes that diverge at various distinct angles relative to the longitudinal axis of the femur F. As can be appreciated, each reamer bushing  660  can correspond to an angle of reaming that will accommodate the profile of any given offset adapter (such as the adapter  452 ,  FIG.  54   ). In some examples, the neutral reamer bushing  660   a  can be used in instances where an offset adapter is unnecessary. It can be appreciated that the femoral offset reamer  710  can also ream an opening in the distal femur that will accommodate a femoral implant boss  720  ( FIG.  54   ). 
     With reference now to  FIG.  53   , femoral trial components  730  can be used to cooperate with the femoral cut-through-trial  570  to trial the prepared distal femur. Again, the femoral cut-through-trial  570  remains fixed to the distal femur F. Prior to using the femoral trial components  730 , a surgeon can cut a box opening into the distal femur with a cutting instrument  731  using the femoral cut-through-trial  570  as a reference. 
     The femoral trial component  730  can generally include a first modular box  732 , a second modular box  734 , a first trial offset adapter  736 , a second trial offset adapter  738  and a third trial offset adapter  740 . The first modular box  732  can be specific to a right femur while the second modular box  734  can be specific to a left femur. Each of the modular boxes  732  and  734  can include wing portions  780  that have passages  782  that receive fasteners  784 . The fasteners  784  can be configured to threadably mate with the threaded bores  592  in the femoral cut-through-trial  570 . The first trial offset adapter  736  can have a 2.5 mm offset, the second trial offset adapter  738  can have a 5 mm offset, and the third trial offset adapter  740  can have a 7.5 mm offset. As can be appreciated, each of the offsets can correspond with the positioning coins  422  and offset reamer bushings  660 . Each of the trial offset adapters  736 ,  738  and  740  can have a threaded boss portion  790  that can threadably mate with a corresponding threaded bore  792  provided in each of the modular boxes  732  and  734 , respectively. A distal augment spacer  794 , and/or a posterior augment spacer  796  can be also used during the trial sequence. In one example, the augment spacers  794  and/or  796  can be magnetically coupled to the femoral cut-through-trial  570 , such as with a magnet  798 . The femur F can then be trialed. 
     In one example, the femoral trial component  730  can be articulated through flexion and extension such that the articulating surface  572  rotates against the trial tibial bearing  300  ( FIG.  30   ). Once the femoral trialing sequence has identified a suitable femoral component, offset adapter and femoral stem, a surgeon can input and implant a femoral component  800 , the offset adapter  452  and a femoral stem  450  as shown in  FIG.  54   . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.