Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Applications No. 60/826,675, filed Sep. 22, 2006 and No. 60/781,025 filed Mar. 10, 2006. The disclosure of each application is incorporated by reference in its entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       Appendix 
       [0003]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    This invention relates generally to surgical devices and, more particularly, to surgical devices used in long bones. 
         [0006]    2. Related Art 
         [0007]    Current modular implant instrument systems are such that there are two separate reamers provided in preparing the femoral canal. One reamer is used to prepare the distal portion of the canal. The reamer is then removed from the drill and the second reamer is attached to the drill to prepare the proximal portion of the canal. Such systems are labor intensive and time consuming. 
         [0008]    Other systems build on or add to the distal reamers. In these systems, the surgeon would have to build the reamer before attaching to the drill. The surgeon is typically required to ream with the distal reamer until the desired distal diameter is achieved. At this point the surgeon has to remove the distal reamer from the drill and add the proximal reamer/s from the end of the distal reamer shaft. In this system, both the proximal reamer and distal reamer have their own depth marks to reference the greater trochanter. Neither reamer has a common reference mark between the reamers. Therefore, the reamers may still be inexact in preparing the distal to proximal portions of the femoral canal because of errors such as tolerance stack and human error. With the addition of sleeves, another tolerance (sleeve length) must be taken into account when reaming the proximal depth. 
         [0009]    Yet another example uses a combination proximal and distal reamer (or plurality of reamers) having a flexible core within the reamer to allow the proximal portion to flex and prepare the medial side of the metaphyseal within the femur. It can also be utilized to fit more within the bow of the femur. This flexible core can create a series of potential issues. First issue is the ability to clean the tool core. With spiral cuts within the core or other means to create flexibility, the potential exists for blood, tissue, or small bone fragments to be caught within the core of the reamer. Another issue is with the potential of the system binding such that the flexible core creates a “coiling” effect and doesn&#39;t allow the reamers to turn and cut due to more torsional resistance of the bone cutting than torsional resistance of the flexible core. 
         [0010]    For a proximal reamer design, the shaft drives both the proximal and distal reamers simultaneously. The elongated shaft guides the proximal broach to remove the medial side of the metaphyseal. Therefore, the purpose of having the modular proximal reamer is to have exposure for the elongated shaft to use as a guide in broaching. 
         [0011]    In other embodiments, the distal reamer is utilized for reaming out the distal segment only. The surgeon disconnects the distal reamer and connects to a proximal reamer. The proximal reamer requires a distal pilot to be attached, for guiding purposes during the preparation of the metaphyseal for the implant. 
         [0012]    Other reamers have a trial head/neck that can be attached to a reamer or broach for a trial reduction. The head/neck trial assembly is attached by a handle to create the version desired. The head/neck assembly can also be adjusted proximally or distally to select the desired height as well. The location of the head/neck assembly relative to the reamer or broach may be difficult to replicate with the implant. There are no references to locate the head/neck assembly in locating height, thus the implant does not necessarily reflect what the surgeon measured during the trial reduction. The surgeon has to somewhat guess and estimate where the implant will be located and place the head/neck assembly to that location accordingly. 
         [0013]    Other systems with a distal reamer, proximal reamer, and trial neck utilize guide channels on the trial neck adaptor to establish anti-rotation and implant orientation. The proximal reamer is required to have straight flutes in order to have guide channels. The guide channels dictate the cutting geometry that can be utilized for the proximal reamer. This system also does not facilitate the ability for the proximal and distal reamers to be modular such that a surgeon can have various proximal reamers for a given distal reamer. 
         [0014]    There remains a need in the art for increasing accuracy while decreasing the number of steps/instruments that is required of systems that utilize proximal/distal reaming systems. In addition, accuracy and decreasing the number of steps may also be achieved with respect to the method of performing a trial reduction for modular implant designs. 
         [0015]    In addition, orienting the trial neck in situ without having to remove the reamer construct, especially in small incisions, may be beneficial. 
       SUMMARY OF THE INVENTION 
       [0016]    In one aspect of the invention, an apparatus for removing bone material comprises a distal cutting instrument and a proximal cutting instrument. The distal cutting instrument has at least one first cutting edge, a shoulder, and a shaft portion. The shaft portion has an anti-rotation feature. The at least one first cutting edge removes bone material when moved in a first direction. The proximal cutting instrument is removably attached to the shaft portion. The proximal cutting instrument has a first end portion and a second end portion. The second end portion contacts the shoulder of the distal reamer when the proximal reamer is mounted to the shaft portion. The proximal reamer has at least one second cutting edge and an aperture. The aperture is adapted to receive the anti-rotation feature of the shaft of the distal reamer. The at least one second cutting edge removes bone material when moved in a second direction. 
         [0017]    In another embodiment of the invention, the at least one first cutting edge is a right-hand cutting flute, and the at least one second cutting edge is a left-hand cutting flute. 
         [0018]    In another embodiment of the invention, the apparatus further comprises a quick connect assembly. The quick connect assembly is mountable to the shaft portion and adapted to contact the first end portion. 
         [0019]    In another embodiment of the invention, the quick connect assembly further comprises a depth guide reference. 
         [0020]    In another embodiment of the invention, the apparatus further comprises a trial neck mountable to the shaft portion and adapted to contact the first end portion. 
         [0021]    In another embodiment of the invention, the apparatus further comprises a trial neck mountable to the distal cutting instrument. 
         [0022]    In another embodiment of the invention, the apparatus further comprises a trial neck mountable to the proximal cutting instrument. 
         [0023]    In another embodiment of the invention, the proximal cutting instrument has a slot that extends an entire length of the proximal cutting instrument. 
         [0024]    In another embodiment of the invention, the anti-rotation feature comprises a square cross-section. 
         [0025]    In another embodiment of the invention, the trial neck further comprises a modular portion. The modular portion is configured to be received within the trial neck. 
         [0026]    In another embodiment of the invention, the modular portion is further configured to have a tapered portion. The tapered portion allows for adjustment of the neck axis of the trial neck. 
         [0027]    In another embodiment of the invention, the first cutting instrument comprises a broach. 
         [0028]    In another embodiment of the invention, the apparatus further comprises an insertion tool configured to attach the trial neck to the cutting instruments. 
         [0029]    In another embodiment of the invention, the trial neck and the first end portion of the proximal cutting instrument are further configured having a circumferential pattern of ridges and valleys. The ridges of the pattern on the trial neck are configured to mate to the valleys of the pattern on the first end portion of the proximal cutting surface. 
         [0030]    In another embodiment of the invention, the insertion tool is further configured to rotate the trial neck relative to the distal and proximal cutting instruments. 
         [0031]    In yet another aspect of the invention, a system for performing a trial reduction comprises a combination cutting instrument and a trial neck. The combination cutting instrument comprises a distal cutting instrument and a proximal cutting instrument. The distal reamer has at least one first cutting edge, a shoulder, and a shaft portion. The shaft portion has an anti-rotation feature. The at least one first cutting edge removes bone material when moved in a first direction. The proximal cutting instrument is removably attached to the shaft portion. The proximal cutting instrument has a first end portion and a second end portion. The second end portion contacts the shoulder when the proximal cutting instrument is mounted to the shaft portion. The proximal cutting instrument has at least one second cutting edge and an aperture. The aperture is adapted to receive the anti-rotation feature. The at least one second cutting edge removes bone material when moved in a second direction. The modular trial neck is operatively connected to the combination cutting instrument. 
         [0032]    Another aspect of the invention provides a method for performing a trial reduction comprising providing a combination cutting instrument having a distal cutting instrument and a proximal cutting instrument. The distal reamer has at least one first cutting edge, a shoulder, and a shaft portion. The shaft portion has an anti-rotation feature. The at least one first cutting edge removes bone material when moved in a first direction. The proximal cutting instrument is removably attached to the shaft portion. The proximal cutting instrument has a first end portion and a second end portion. The second end portion contacts the shoulder when the proximal cutting instrument is mounted to the shaft portion. The proximal cutting instrument has at least one second cutting edge and an aperture. The aperture is adapted to receive the anti-rotation feature. The at least one second cutting edge removes bone material when moved in a second direction. The modular trial neck is operatively connected to the combination cutting instrument. Bone material is removed by moving the combination cutting instruments in the first direction and in the second direction. A modular trial neck is attached to the combination cutting instrument. A trial reduction of the implant is performed. 
         [0033]    In yet another aspect of the invention, a method of preparing a long bone for an implant comprises cutting a distal portion of the long bone by moving a first cutting instrument in a first direction. Another step provides coupling a second cutting instrument to the first cutting instrument. A proximal portion of the long bone is cut by moving the coupled cutting instruments in a second direction different from the first direction such that when the first cutting instrument is moved in the second direction, the first cutting instrument does not cut the distal portion of the long bone. 
         [0034]    Another aspect of the invention provides a method for preparing a trial insert for a long bone. The method comprises preparing a canal in the long bone using at least one cutting instrument. The cutting instrument has the shape of the trial insert. The method also comprises adjusting a trial neck relative to the cutting instrument and coupling the trial neck to the cutting instrument. The trial neck may then be sized relative to the acetabulum for proper version of the trial implant. 
         [0035]    The invention has several advantages over prior devices and techniques. First, the devices may increase accuracy while decreasing the number of steps/instruments that is required of systems that utilize proximal/distal reaming systems. Increased accuracy may reduce the amount of natural bone removed from the femur and may reduce the amount of further preparation after the initial reaming. In addition, reducing the number of steps and instruments may reduce total operation time. 
         [0036]    Second, increased accuracy and decreased number of steps may also be achieved with respect to the method of performing a trial reduction for modular implant designs, at least partially because the trial neck may be oriented in situ without having to remove the reamer construct. 
         [0037]    Further features, aspects, and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0038]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the present invention and together with the description, serve to explain the principles of the invention. In the drawings: 
           [0039]      FIG. 1  is an exploded view of parts of a femoral reamer according to an embodiment of the invention. 
           [0040]      FIG. 2  is an exploded view of the parts of  FIG. 1  and a quick connect assembly. 
           [0041]      FIG. 3A  is a view of a trial femoral implant including the parts of the femoral reamer of  FIG. 1 . 
           [0042]      FIG. 3B  is a view of a femoral implant. 
           [0043]      FIGS. 4A and 4B  are views of trial necks according to an aspect of the invention. 
           [0044]      FIG. 5  is an exploded view of a distal femoral reamer and a proximal broach according to an embodiment of the invention. 
           [0045]      FIG. 6  is a close-up view of the distal femoral reamer and the proximal broach of  FIG. 5 . 
           [0046]      FIG. 7  is a view of an insertion tool inserting a trial into a femur according to an aspect of the invention. 
           [0047]      FIG. 8  is a cut-away view of the femur of  FIG. 7  showing the trial. 
           [0048]      FIG. 9  is a view of an insertion tool according to an aspect of the invention. 
           [0049]      FIGS. 10A and 10B  are exploded views of trial inserts and trial insertion tools according to an aspect of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0050]    Referring to the accompanying drawings in which like reference numbers indicate like elements,  FIG. 1  is an exploded view of parts of a femoral reamer  10  according to an embodiment of the invention. The femoral reamer  10  includes two major components, a distal reamer  12  and a proximal reamer  14 . The distal reamer  12  prepares the femur for receiving a stem of a femoral implant and the proximal reamer  14  prepares the femur for receiving a sleeve of a femoral implant. The distal reamer  12  includes a thick depth shaft  18 , a shoulder  20 , a distal reamer shaft  22  and a quick connect mating portion  24 . The quick connect mating portion  24  includes a mounting tip  26  and a groove  28 . The quick connect mating portion  24  is attached to a drill. 
         [0051]    The distal reamer  12  includes right-hand cutting flutes  30  while the proximal reamer  14  includes left-handed cutting flutes  32 . The right-handed cutting flutes  30  have edges on the flutes that cut in a forward cutting action when the reamer  10  is rotated. The edges of the flutes of the distal reamer  12  cuts bone in preparing the distal aspects of the femur by connecting the reamer  10  at the quick connect mating portion  24  to a drill. The reamer  10  may cut the femur in a clockwise manner. The surgeon will ream up (starting at smaller diameters) to the desired distal diameter based on pre-operative templating. In conjunction, the surgeon will ream to a depth based on the implant size. While this embodiment describes one way in which the distal and proximal reamers may be moved relative to one another, those having ordinary skill in the art understand that other relative motions, such as switching the directions of the flutes  30  and  32  or combining axial motion and rotational motion may be implemented. After preparing the distal femur, the proximal femur may be prepared. 
         [0052]    In order to prepare the proximal portion of the femur, the distal reamer  12  is disconnected from the drill and the proximal reamer  14  is attached to the distal reamer  12 . The proximal reamer  14  may be slid onto the shaft  22  of the distal reamer  12 . The shaft  22  of the distal reamer  12  may have a square cross-section to engage with a square aperture within the proximal reamer  14 . The shaft  22  may transfer torque and rotation from the distal reamer  12  to the proximal reamer  14 . The proximal reamer  14  may be advanced on the distal reamer  12  until the proximal reamer  14  rests upon the shoulder  20  of the depth shaft  18 . The depth shaft  18  sets the relative depth of the distal reamer  12  to the proximal reamer  14 . The depth shaft  18  may be larger in diameter in order to minimize stresses on the distal reamer  12 . 
         [0053]    In other embodiments, the cross section of the shaft  22  and the aperture in the proximal reamer  14  may be other shapes which allow the proximal reamer  14  to be coupled to the shaft  22  of the distal reamer  12 . The cross-section of the shaft  22  provides for anti-rotation of the proximal reamer  14  relative to the distal reamer  12 . When the cross-section is in the shape of a square, then there are four possible rotational orientations of the proximal reamer  14  relative to the distal reamer  12  in which the proximal reamer  14  may be seated on the shaft  22 . Other cross-sectional embodiments, such as a hexagon or octagon, would have  6  and  8  possible rotational orientations of the proximal reamer  14  relative to the distal reamer  12 , respectively. Other cross-sectional shapes, such as a star shape, may also transfer torque and rotation to the proximal reamer  14 . 
         [0054]    The proximal femur is prepared using the proximal reamer  14 . The surgeon may ream up (starting at a small diameter proximal reamer  14 ) the proximal portion of the femur by rotating the drill in a counterclockwise manner. The edges of the flutes  32  of the proximal reamer  14  are left-handed cutting flutes. When the reamer  10  is rotated counterclockwise, the left-handed cutting flutes  32  cut the proximal femur. However, the distal reamer  12 , when rotated counterclockwise, does not cut the distal femur because the edges of the right-handed cutting flutes  30  of the distal reamer  12  only cut the distal femur when the reamer  10  is rotated clockwise. When rotated counterclockwise, the distal reamer  12  acts as a guide to prepare the proximal femoral canal minimizing additional bone being removed distally. Pre-operative templating may determine the final proximal reamer diameter. In conjunction, the surgeon will ream to a depth based on the implant size. In addition, the distal reamer  12  may limit the depth of the proximal reamer  14  and act as a guide for the orientation of the proximal reamer  14 . 
         [0055]    In another embodiment, the proximal reamer may include a slot that runs through the overall length of the proximal reamer. The slot allows the proximal reamer to be “side-loaded” onto a distal reamer without disconnecting the distal reamer from the drill. In such an embodiment, the proximal reamers contain left-hand cutting flutes so that the drill must be set to reverse in order for the proximal reamer to cut. By using a side loading distal reamer, sizing changes between smaller diameter and larger diameter proximal reamers may also be made without disconnecting the distal reamer from the drill. 
         [0056]    A side loaded proximal reamer may be attached to the distal reamer by two parallel flats on the shaft of the distal reamer. The flats, in combination with the slot of the proximal reamer, allow for the proximal reamer to be indexed and locked in position with the aid of a spring loaded plunger. The spring loaded plunger may overlap a portion of the proximal reamer to form an interference fit between the proximal reamer and distal reamer. While the flats may transfer torque and rotation from the distal reamer to the proximal reamer, an interference fit may hold the proximal reamer in axial alignment with the distal reamer. 
         [0057]    In operation, the combination reamer  10  allows for variable reaming size during distal and proximal femur preparation, according to the size of the implant used in the femur. By maintaining the distal reamer position during proximal reaming, fewer stack errors from referencing points relative to other points may be achieved. For example, angular offsets between the proximal and distal portions are minimized, as well as linear offsets such as depth or lateral movement. Any eccentricity between the shape of the reamer and the shape of the relief may be minimized because less jitter may result when only one of the distal or proximal reamers cuts at one time. This may result in less total bone removal by more accurately removing only the bone necessary to remove. In addition, the orientation may allow for better placement of the implant within the femoral canal with more uniform contact between the implant and the natural bone. 
         [0058]    The quick connect mating portion  24  includes the mounting tip  26  and the groove  28 . The groove  28  is an indentation in the shaft  22  and is configured to receive a ball bearing as described in  FIG. 2 . The mounting tip  26  may have a cross-section similar to the distal reamer shaft  22 , or may have a cross-section smaller than the shaft  22 . However, the cross-section of the mounting tip  26  should be larger than the cross-section of the groove  28 . The mounting tip  26  may be threaded so that a trial implant may be attached to the distal reamer  12 . In other embodiments, the mounting tip may be configured with other fasteners for attaching the distal reamer  12  to the trial implant. 
         [0059]    Turning now to  FIG. 2 ,  FIG. 2  is an exploded view of the parts of  FIG. 1  and a quick connect assembly  40 . The quick connect assembly  40  includes an inner cylinder  42 , an outer cylinder  44 , a flange  46 , a transverse pin  48  and a drill connector  50 . The inner cylinder  42  is axially slidable within the outer cylinder  44 , and is biased at the transverse pin  48 . The transverse pin  48  is fixed axially to the outer cylinder  42  and extends through the outer and inner cylinders  42  and  44 . The pin extends through the inner cylinder  42  within a slot. The slot also houses a spring which biases the drill connector  50  of the inner cylinder  42  axially away from the flange  46 . 
         [0060]    When the inner cylinder  42  is axially slid within the outer cylinder  44  (i.e., the drill connection  50  is depressed toward the flange  46 ), a pair of bearings are slid out of the bottom of the quick connect assembly  40 . The bearings extend radially outward from the quick connect assembly  40  to a distance greater than the inner diameter of the outer cylinder  44 . With the bearings extending out from the inner cylinder  42 , the quick connect assembly  40  is positioned to connect to the reamers  12  and  14 . 
         [0061]    The proximal reamer  14  is seated on the distal reamer  12 . When the proximal reamer  14  is seated on the distal reamer  12 . the mounting tip  26  and the groove  28  are located above the proximal reamer  14 . Thus, the mating portion  24  of the distal reamer  12  is positioned for attachment to the quick connect assembly  40 . The quick connect assembly  40  is slid over the mounting tip  26  and the groove  28 . The bearings, extended outward, are slid over the groove  28 . The drill connection  50  of the inner cylinder  42 , then, may be axially slid away from the flange  46  and the bearings forced into the groove  28  by the inner surface of the outer cylinder  44 . The inner cross-section of the inner cylinder  42  may be shaped like the cross-section of the distal reamer shaft  22  so that the torque and rotation from the drill may be transferred from the quick connect assembly  40  to the reamers  12  and  14 . 
         [0062]    When the quick connect assembly  40  is attached to the reamers  12  and  14 , the depth of the distal reamer  12  is fixed relative to the quick connect assembly  40 . The quick connect assembly  40  may secure a tight axial fit of the proximal reamer  14  between the quick connect assembly  40  and the distal reamer  12 . In addition, whether the proximal reamer  14  is attached to the distal reamer  12  does not change the depth of the distal reamer  12 . Because the distance is fixed, the quick connect assembly  40 , then, may also have indicator lines for each implant size on the quick connect assembly  40 . These indicator lines may reference the tip of the greater trochanter, and may be etched into the visible portions of the inner or outer cylinders  42  and  44 . Thus, the quick connect assembly  40  may act as a single reference guide for both the distal reamer  12  and the proximal reamer  14 . 
         [0063]    Turning now to  FIG. 3A ,  FIG. 3A  is a view of a trial femoral implant  60  including parts of the femoral reamer of  FIG. 1 . The trial implant  60  includes the distal reamer  12 , the proximal reamer  14  and a trial neck  62 . The trial neck  62  is oriented relative to the reamers  12  and  14  similar to the orientation of the neck of an implant. When attached to the reamers  12  and  14 , the trial neck  62  acts as an implant for correctly positioning the femoral component relative to the acetabular component of the implant. 
         [0064]    After proximal and distal reaming is complete, the quick connect assembly is detached from the shaft of the distal reamer  12 . The proximal and distal reamers are still located within the femoral canal. The trial neck  62  is then connected to the shaft of the distal reamer  12 , to the proximal reamer  14 , or any combination of the two. The trial neck  62  may be angularly oriented about the axis of the femur, thus providing the surgeon with the desired version angle for the implant prosthesis. The surgeon may then perform a trial reduction of the implant by using the proximal and distal reamers  14  and  12  in conjunction with attaching a trial head to the trial neck  62 . 
         [0065]    The trial neck  62  may be attached to the distal reamer  12  at the mounting tip. For example, a threaded connector may be used through an aperture, as shown in  FIGS. 4A and 4B  of the trial neck  62 , to fix the trial neck  62  to the reamers  12  and  14 . When the trial neck  62  is attached, the distance from a tip  64  of the distal reamer  12  to the trial neck  62  is fixed. Similarly, a shoulder  66  and upper flared portion  68  of the proximal reamer  14  as well as a head  70  of the trial neck  62  are also fixed in orientation and position relative to one another. These positions and orientations also match the positions and orientations of an implant, as shown in  FIG. 3B . 
         [0066]    Turning now to  FIG. 3B ,  FIG. 3B  is a view of a femoral implant  80 . A distal tip  82  of the femoral implant  80 , a distal shoulder  84 , a flared proximal shoulder  86 , and a neck head  88  partially define the geometry of the implant  80 . The geometry of the implant  80  is approximated by the trial  62  of  FIG. 3A . The proximal reamer  12  reams to a depth equivalent to the depth of the tip  82  of the implant  80 . The proximal reamer  14  approximates the shape of the implant  80  between the distal and proximal shoulders  84  and  86 . The fixed head  88  of the implant  80  is approximated by the trial head  70 . As discussed below, the ability to orient and size the trial head  70  allows for proper implantation of the implant  80 . 
         [0067]    Turning now to  FIGS. 4A and 4B ,  FIGS. 4A and 4B  are views of trial necks  100  and  110  according to an aspect of the invention. The trial necks  100  and  110  include a poker chip mating surface  102  and  112 , recessed portions  104  and  114 , and cavities  108  and  118 . The trial neck  100  of  FIG. 4A  includes an alignment guide  106 , and the trial neck  110  of  FIG. 4B  includes a fin  116 . 
         [0068]    The poker chip mating surfaces  102  and  112  are adjustable in rotational orientation relative to the reamers. The mating surfaces  102  and  112  are formed such that when the surfaces  102  and  112  are mated to like surfaces on a reamer or other part of the trial implant, the ridges on the trial necks  100  and  110  are seated within the valleys of the like surfaces on the reamer. Similarly, the valleys on the trial necks  100  and  110  are seated within the ridges of the like surfaces on the reamer. The trial neck,  100  or  110 , then, may be rotated about a general central axis of the reamers. The patterns of the poker chip surface  102  and  112  may be any general surface that allows for a plurality of positions in which to fix the trial neck  100  or  110  to the reamers. In addition, the pattern does not have to be complete around the cavities  108  and  118 . 
         [0069]    The cavities  108  and  118  are configured to receive a connector in order to compress the trial necks  100  and  112  to the reamers, respectively. A connector, such as a T-nut, may be used to fix the trial necks  100  and  110  to the threaded connector of the distal reamer. The trial neck, then, is screwed in place between the connector and the reamer. Thus, when connected by a connector, the trial neck  100  or  110  may be fixed in place for trial reduction. The orientation of the trial neck  100  or  110  may be adjusted by using a tool mated to the recesses  104  and  114  to rotate the trial head  100  and  110 . 
         [0070]    The recesses  104  and  114  may be similar to a spanner head of a screw. The recesses  104  and  114  receive prongs from a tool (shown in  FIGS. 7-10 ) which may provide rotation to the trial head. By placing the recesses  104  and  114  on the periphery of the trial necks  100  and  110 , minimal torque may be used to rotate the trial neck. In addition, the peripheral placement of the recesses  104  and  114  may minimize interference with the connector used through the cavities  108  and  118  to fix the trial necks  100  and  110  to the reamers. While the spanner head-like design of the recesses  104  and  114  have been used in this example, other interfaces designed to transfer rotation and torque from a tool to the trial head  100  or  110  may be used. 
         [0071]    The trial necks  100  and  100  may also have certain features that help orient the neck relative to the bony anatomy. Features such as the groove  106  or fin  116  may be used as a guide to cauterize or draw reference marks on the anatomical structures or natural features to reference the position of the trial neck  100  or  110  relative to other anatomical landmarks or structures. 
         [0072]    Rotation of the trial neck  100  or  110  may be limited by an anti-rotational element to prevent rotation of the trial neck with respect to the bone. The element may be a fin such as the fin  116 , spike, screw, or other structure or method that engages the bone to prevent rotation of the trial neck  100  or  110 . Likewise, the proximal and distal reamers may have structures or methods to prevent rotation of the trial implant relative to the bone. This may be accomplished by, for example, a collar fitted over the reamers to prevent rotation, screws projecting into the bone, grooves that accept pins or screws placed between the trial implant and the bone, or any other structure or method to prevent rotation. The methods and structures that provide rotational alignment of the reamer may also be used as a way to match the alignment of the implant to the trial and associated reamers. 
         [0073]    Turning now to  FIG. 5 ,  FIG. 5  is an exploded view of a distal femoral reamer  120  and a proximal broach  122  according to an embodiment of the invention. The broach  122  is configured to connect to an impactor tool  124 , which includes a handle  126  and a connector  128 . The broach  122  and the tool  124  have a cavity  130  configured to receive a shaft  132  of the distal reamer  120 . The shaft  132  aligns the proximal cutting instrument  122  along the axis of the distal reamer  120 . The handle  126  allows a surgeon to manipulate the broach  122  from the end of the tool  124 . The connector  128 , in this embodiment a threaded portion of the tool  124 , is configured to receive the broach  122 , or other cutting instrument. Because the broach  122  is not integral to the tool  124 , the size of the broach  122  may be changed according to the needed relief for the implant. 
         [0074]    The cutting instruments (the distal reamer  120  and the broach  122 , in this embodiment) provide another method of preparing a portion of the bone. Other cutting instruments such as rasps or files may be used to remove bone so that the shape in relief approximates the shape of an implant. The cutting instruments may use the distal cutting instrument (in this example, the distal reamer) as a guide. The cutting instruments may prepare any number of geometries either symmetrical or asymmetrical. The instrument may have any number asymmetrical features such as spouts, fins, or bodies. 
         [0075]    Turning now to  FIG. 6 ,  FIG. 6  is a close-up view of the distal femoral reamer  120  and the proximal broach  122  of  FIG. 5 . As described previously, the shaft  132  of the distal reamer  120  is received within the cavity  130  to guide the broach  122  along the axis of the distal reamer  120 . The threaded portion  128  of the tool connects the tool to the broach  122 . Cutting edges  140  of the broach  122  cut the proximal bone when the broach  122  is moved axially along the shaft  132 . The cross-section of the shaft  132 , which in this embodiment is square, keeps the broach  122  from rotating. Rotation would cause an asymmetrical section  142  to rotate and remove more bone than desired. 
         [0076]    The cutting edges  140  of the broach  122  may be circumferential edges separated axially along the axis of the broach  122 . The cutting edges  140  may also extend around the asymmetrical portion  142  of the broach  122  to allow for cutting an asymmetrical relief into the bone. While the cutting edges of the broach  122  in this embodiment are circular, other patterns for the cutting edges, such as spiral edges, may be used on the broach  122 . 
         [0077]    Turning now to  FIG. 7 ,  FIG. 7  is a view of an insertion tool  150  inserting a trial  152  into a femur according to an aspect of the invention. The insertion tool  150  includes an outer member  154  and an inner member  156 . The outer member  154  includes prongs  158  configured to rotate the trial. The tool  150  may reference the position or version of the trial neck to the bone with the position and orientation of the prongs  158 . Features may reference certain anatomical landmarks or prepositioned landmarks such as cautery marks or pin anchors, or to instruments either part of the construct or in the surgical field. 
         [0078]    The inner member  156  includes a portion configured to fix the trial  152  to the reamers. The portion of the inner member  156  may include a driver head configured to interface with a screw head on the trial  152 . As previously described, the screw head would connect to the mounting tip of the distal reamer through the cavity in the trial neck to fix the trial neck  152  to the reamer. 
         [0079]    The prongs  158  of the outer member  154  attach to the recesses on the trial head to rotate the trial neck  152  within the femoral canal. In order to adjust the trial neck  152 , the tool  150  is used to release the trial neck connection from the reamer. The tool  150  may hold, reposition, and reconnect the trial neck  152 . Likewise the tool  150  may also introduce or remove the trial neck from the surgical field. 
         [0080]    Turning now to  FIG. 8 ,  FIG. 8  is a cut-away view of the femur of  FIG. 7  showing the trial.  160 . The trial  160  is axially aligned through the distal reamer  162 , the proximal reamer  164 , the trial neck  166  and the insertion tool  168 . The relative orientation of the insertion tool  168  to the reamers  162  and  164  sets the version and orientation of the trial neck  166  for the trial  160 . Thus, the trial  160  may be made up of the reamers  162  and  164  and a trial neck  166 , allowing for a modular sizing, versioning, and orienting of the implant by allowing multiple sizes of trial heads and versions of trial heads in a single step. 
         [0081]    Turning now to  FIG. 9 ,  FIG. 9  is a view of an insertion tool  170  according to an aspect of the invention. A distal reamer  172 , a proximal reamer  174  and a sleeve impactor ring  176  are aligned with the tool  170 . Prongs  180  impact the impactor ring  176 , which would impact a proximal sleeve. A trial neck may also be attached to the modular implant sleeve impactor  176 , for example through a quick connect assembly to the sleeve impactor  176 . By disconnecting the impaction portion of the sleeve impactor  176 , the trial neck may be connected. Thus, the surgeon can perform a trial reduction including a proximal sleeve implant. 
         [0082]    Turning now to  FIGS. 10  A and  10 B,  FIGS. 10A and 10B  are exploded views of trial inserts  201  and  211  and trial insertion tools  200  and  210  according to an embodiment of the invention. The trial inserts include a trial neck  202  and  212 , a proximal reamer  204  and  214 , distal reamer  206  and  216 , and a connector  208  and  218 . The trial  211  also includes a modular member  220  having a tapered portion  222  for insertion into the trial neck  212 . The connectors  208  and  218  fix the trial neck  202  and  212  to the distal reamers  206  and  216  at the mounting tips  230  and  240 . 
         [0083]    In order to fine tune the anatomical fit of an implant, the modular member  220  is mated with the trial neck  218 . The tapered portion  222  may adjust the geometrical length, height or angulation of the neck axis in order to restore the patient&#39;s anatomical kinesthetics. The tapered portion  222  may also have features that orient the neck relative to the bony anatomy, as mentioned above. The modular member  220  may be used on either an implant or trial. 
         [0084]    The method of preparing the femoral canal includes attaching a distal cutting instrument to a drill. The cutting instrument is inserted into the IM canal and the distal portion is shaped by moving, the distal cutting instrument in a first direction. When the distal portion is sufficiently shaped, then the drill is disconnected from the distal cutting instrument, and the distal cutting instrument may remain within the IM canal. A proximal cutting instrument is placed onto the distal cutting instrument over the shaft of the distal cutting instrument. The drill is then attached to the cutting instrument. In one embodiment, the drill is attached to the distal cutting instrument through a quick connect assembly. The proximal portion of the canal is shaped, and the canal may then be properly sized for an implant. 
         [0085]    The method of preparing a trial insert includes shaping a distal portion by moving a first cutting instrument in a first direction and a proximal portion of a femur by moving a second cutting instrument in a second direction. A trial neck is attached to one of the cutting instruments. The trial neck is rotationally adjustable relative to the cutting instruments. A head of the trial neck may also be adjustable relative to the trial neck to adjust the version of the trial neck. 
         [0086]    In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained. 
         [0087]    The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. 
         [0088]    As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.

Technology Category: 1