Abstract:
A surgical instrument is disclosed that facilitates the implantation of one of a number of differently sized or differently configured hip stem prostheses into a proximal end of a femur while also providing a surgeon with a substantial amount of rotational control over the prosthesis during the implantation. A suitable hip stem prosthesis is selected from a family of hip stem prostheses of varying sizes and dimensions. The surgical instrument attaches to the selected hip stem prosthesis via first and second spaced engagement portions such that the instrument is operable to exert rotational control over the selected hip stem prosthesis. The first engagement portion is an impaction portion configured to engage a corresponding impaction feature on a proximal body portion of the hip stem prosthesis. The second engagement portion is an adjustable clamping portion configured to clampingly receive the neck of the hip stem prosthesis, regardless of the prosthesis size.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under Title 35, U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/468,386, filed Mar. 28, 2011, the entire disclosure of which is hereby expressly incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    1. Field of Invention 
         [0003]    The present disclosure relates to a surgical instrument, and in particular to a surgical instrument for facilitating the implantation of a prosthetic component, such as a hip prosthesis. 
         [0004]    2. Description of Related Art 
         [0005]    Prostheses are commonly utilized to repair and/or replace damaged bone and tissue in the human body. For example, a hip prosthesis may be implanted to replace damaged or destroyed bone in the femur and/or acetabulum and recreate the natural, anatomical articulation of the hip joint. During a total hip arthroplasty procedure, the surgeon may ream the acetabulum of a patient to prepare a reamed area for receiving an acetabular cup prosthesis, and rasp the proximal femur to provide a rasped area for receiving a femoral hip stem prosthesis that includes a stem and neck portion. The femoral stem portion includes a bone-engaging surface configured to be accepted into the rasped area of the proximal femur, and the femoral neck portion includes a head component having an articulating surface to articulate with the acetabular cup prosthesis seated within the acetabulum, for example. The articulating head component is seated atop a head region of the femoral neck portion that is utilized to secure the femoral head component to the hip stem prosthesis. 
         [0006]    Once the femur is prepared, a femoral hip stem prosthesis having selected characteristics, such as offset and leg length dimensions, is inserted into the prepared femur. Offset and leg length dimensions as used within this disclosure are described in the Zimmer®M/L Taper Hip Prosthesis with Kinectiv® Technology brochure submitted herewith in an Information Disclosure Statement, the entire disclosure of which is hereby explicitly incorporated by reference herein. The center of the head region of the neck portion of the femoral hip stem prosthesis may be offset substantially in a medial or lateral direction with reference to a person&#39;s anatomy, for instance, from a nominal center of rotation, with the medial-lateral offset dimension determined with reference to a longitudinal axis of the femoral hip stem prosthesis. Additionally, the center of the head region may be substantially in a proximal or distal direction spaced from a nominal center of rotation along a leg length dimension aligned with the longitudinal axis of the femoral hip stem prosthesis. Leg length and offset dimensions may be determined using suitable templates together with x-ray images, for example. 
         [0007]    Typically, a surgeon uses a surgical instrument to facilitate the implantation of a hip stem prosthesis. The utilized surgical instrument may be, for example, an inserter that assists with insertion of the hip stem prosthesis and/or an impactor that assists with seating of the prosthesis within a prepared canal of the proximal femur. 
       SUMMARY 
       [0008]    The present disclosure provides a surgical instrument for facilitating the implantation of one of a number of differently sized or differently configured hip stem prostheses into a proximal end of a femur while also providing a surgeon with a substantial amount of rotational control over the prosthesis during the implantation. A suitable hip stem prosthesis is selected from a family of hip stem prostheses of varying sizes and dimensions. The surgical instrument attaches to the selected hip stem prosthesis via first and second spaced engagement portions such that the instrument is operable to exert rotational control over the selected hip stem prosthesis. The first engagement portion is an impaction portion configured to engage a corresponding impaction feature on a proximal body portion of the hip stem prosthesis. The second engagement portion is an adjustable clamping portion configured to clampingly receive the neck of the hip stem prosthesis, regardless of the prosthesis size. 
         [0009]    The instrument includes an actuation assembly that allows adjustment of the clamping portion to clamp either a first neck portion of a first hip stem prosthesis or a second neck portion of a second, differently configured hip stem prosthesis. When the clamping portion clamps a femoral neck portion and the impaction portion of the instrument is engaged with the corresponding impaction feature of the proximal body portion of the hip stem prosthesis, the prosthesis is connected to the surgical instrument via the impaction and clamping portions. With this dual engagement, the impaction portion of the surgical instrument acts as an anchoring point while the clamping portion of the surgical instrument provides a clamping force to allow the surgical instrument to tightly clamp and control rotation of the attached hip stem prosthesis. 
         [0010]    The present disclosure, in one form thereof, comprises a surgical instrument for use with a hip stem prosthesis, the hip stem prosthesis including a proximal body portion and a neck portion, the surgical instrument including a body, a first engagement portion engageable with the proximal body portion of the hip stem prosthesis, the first engagement portion aligned substantially along a first axis, and a second engagement portion receivable about, and engageable with, the neck portion of the hip stem prosthesis, the second engagement portion spaced from the first axis and adjustably connected to the body to vary the spacing of the second engagement portion from the first axis. 
         [0011]    The present disclosure, in another form thereof, comprises a surgical instrument for use with a hip stem prosthesis, the hip stem prosthesis including a proximal body portion and a neck portion, the surgical instrument including first engagement means for engaging with the proximal body portion of the hip stem prosthesis, the first engagement means aligned substantially along a first axis, and second adjustable engagement means for engaging around the neck portion of the hip stem prosthesis, the second adjustable engagement means adjustable to vary the spacing of the second adjustable engagement means from the first axis. 
         [0012]    The present disclosure, in a further form thereof, comprises a method of implanting a hip stem prosthesis, the hip stem prosthesis including a proximal body portion and a neck portion, the method including: obtaining a surgical instrument including a first engagement portion and a second engagement portion, the first engagement portion aligned substantially along a first axis; engaging the first engagement portion with the proximal body portion of the hip stem prosthesis; placing the second engagement portion around the neck portion of the hip stem prosthesis; and moving the second engagement portion towards the first axis to clamp the second engagement portion to the neck portion of the hip stem prosthesis to secure the surgical instrument to the hip stem prosthesis. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following descriptions of embodiments of the disclosure taken in conjunction with the accompanying drawings, wherein: 
           [0014]      FIG. 1  is an elevational view of an exemplary hip stem prosthesis with ranging leg length and offset dimensions shown in dashed lines; 
           [0015]      FIG. 2  is a perspective view of the surgical instrument of the present disclosure attached to a hip stem prosthesis via a first engagement portion that is an impaction portion and a second engagement portion that is a clamping portion; 
           [0016]      FIG. 3  is an exploded, perspective view of the surgical instrument attached to a hip stem prosthesis, showing an impaction head of the surgical instrument having a bore extending therethrough and a driver of the surgical instrument for insertion into the bore; 
           [0017]      FIG. 4  is a fragmentary, elevational view of the surgical instrument of  FIG. 2  attached to the hip stem prosthesis such that the impaction portion is attached to a proximal body portion of the hip stem prosthesis and the clamping portion is attached to a tapered relief portion of the neck portion beneath the head region of the hip stem prosthesis; 
           [0018]      FIG. 5  is a fragmentary, perspective view of  FIG. 3  after insertion of the driver into the surgical instrument bore, the driver having a male hex end feature at a distal end for engagement with a female hex end feature on a proximal portion of a threaded rod disposed within the body portion of the surgical instrument; 
           [0019]      FIG. 6  is a fragmentary, perspective view of  FIG. 3  showing the male hex end feature of the driver engaged with the female hex end feature of the threaded rod wherein rotational movement of the driver causes a corresponding rotation of the mating hex end feature that results in a longitudinal translation of an adjustment block with respect to the threaded rod; 
           [0020]      FIG. 7  is a fragmentary perspective view of impaction and clamping portions at the lower end of a body portion of the surgical instrument and their respective corresponding engagement to a proximal body portion and a neck portion of the hip stem prosthesis; 
           [0021]      FIG. 8  is a front perspective view of the engagement shown in  FIG. 7 ; 
           [0022]      FIG. 9  is a fragmentary view of the engagement shown in  FIG. 8 , particularly showing a pair of flat surfaces of a rear wall of the clamping portion of the surgical instrument in engagement with the neck portion of the hip stem prosthesis; 
           [0023]      FIG. 10  is a fragmentary view of another embodiment of the surgical instrument with the neck portion shown in phantom; 
           [0024]      FIG. 11A  is a perspective view of the clamping portion of the surgical instrument of the present disclosure separated from the remainder of the surgical instrument and including channels along an inner wall of the clamping portion; 
           [0025]      FIG. 11B  a perspective view of the clamping portion of the surgical instrument of the present disclosure separated from the remainder of the surgical instrument and showing inserts received within the channels of  FIG. 11A  for contacting the neck/head component of the hip stem prosthesis of  FIG. 2 ; 
           [0026]      FIG. 12A  is a fragmentary, perspective view of the clamping portion of the surgical instrument in a first position prior to engagement with the neck/head component of the hip stem prosthesis; 
           [0027]      FIG. 12B  is a fragmentary, perspective view of the clamping portion being rotated about a linkage assembly or link lever of the surgical instrument and being pushed into a downward position to engage with the neck portion of the hip stem prosthesis; 
           [0028]      FIG. 12C  is a fragmentary, side elevational view of the clamping portion of the surgical instrument about to be engaged with a tapered relief portion on the neck portion and beneath the head component of the hip stem prosthesis; 
           [0029]      FIG. 12D  is a fragmentary, elevational view of the engagement of the clamping portion of the instrument engaged with the tapered relief portion on the neck portion and beneath the head component of the hip stem prosthesis; and 
           [0030]      FIG. 13  schematically shows the surgical instrument of the present disclosure attached to hip stem prostheses of two different sizes, one shown in solid lines and the other in dashed lines, the prostheses having two different leg length and offset dimensions. 
           [0031]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the disclosure, and such exemplifications are not to be construed as limiting the scope of the disclosure in any manner. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    A surgical instrument usable as an impactor and an inserter that facilitates the implantation of a hip stem prosthesis into a proximal end of a femur and which, when attached to the hip stem prosthesis, provides rotational control of the hip stem prosthesis is disclosed. The surgical instrument is able to attach to hip stem prostheses of multiple sizes and configurations, as described below. Also as described below, the surgical instrument includes a first engagement portion that is an impaction portion for engagement with a corresponding impaction feature on a proximal body portion of a hip stem prosthesis and a second engagement portion that is a clamping portion for receipt of and to clamp a femoral neck/head component of the hip stem prosthesis. 
         [0033]    The clamping portion includes an annular engagement member or collar for engaging a tapered surface beneath the head component of the hip stem prosthesis. The annular collar is adjustable via an actuation assembly to clamp to either a first hip stem prosthesis or a second, differently sized hip stem prosthesis, as described further below. The engagement of both the clamping portion and the impaction portion allows for a rotatably controllable attachment of the prosthesis to the surgical instrument, as described below. 
         [0034]    Within this disclosure, the terms horizontal and vertical are used to respectively describe the displacement of offset and leg length dimensions with respect to centers of head regions of different hip stem prostheses. Horizontal and vertical are used generally to delineate directions that are perpendicular to one another. Within the context of this disclosure, an indication of a vertical positioning corresponds to a proximal or distal positioning with respect to anatomical terminology. Further, an indication of a horizontal positioning corresponds to a medial or lateral positioning with respect to anatomical terminology. 
         [0035]    Referring to  FIG. 1 , exemplary hip stem prosthesis  22  is shown that includes stem portion  24 , proximal body portion  25 , and projecting neck portion  26 . Particularly, neck portion  26  projects from proximal body portion  25 , which is disposed above stem portion  24 . Neck portion  26  includes head region  28  and tapered relief portion  30  below head region  28 . Head region  28  is separated from stem portion  24  and proximal body portion  25  via tapered relief portion  30 . Proximal body portion  25  and stem portion  24  include longitudinal axis L of prosthesis  22 . An exemplary hip stem prosthesis is any hip stem prosthesis of the VerSys® Hip System manufactured and sold by Zimmer, Inc. of Warsaw, Ind. 
         [0036]      FIG. 1  illustrates three different hip stem prostheses including substantially aligned longitudinal axes L such that a single longitudinal axis L will be referenced herein. The three different hip stem prostheses respectively include three different head centers C 1 , C 2 , and C 3 . For example, hip stem prosthesis  22  includes head region  28  (shown in solid lines) having head center C 1 . Hip stem prosthesis  22 ′ includes head region  28 ′ (shown in dashed lines) having head center C 2  that is horizontally offset from head center C 1 , and horizontally offset with respect to longitudinal axis L, along axis or line H. 
         [0037]    Further, hip stem prosthesis  22 ″ includes head region  28 ″ (shown in dashed lines) having head center C 3 . Head center C 1  of hip stem prosthesis  22  (shown in solid lines) is vertically distanced from head center C 3  of head region  28 ″ of hip stem prosthesis  22 ″ (shown in dashed lines) along axis or line V, that is substantially parallel to longitudinal axis L, indicating the different leg length dimensions of neck portions  26 ,  26 ″ of the respective prostheses. 
         [0038]    Referring to  FIG. 2 , surgical instrument  20  is shown attached to hip stem prosthesis  22 . Surgical instrument  20  includes body portion  32  having bore  34  ( FIG. 3 ) extending through body portion  32 . Driver  38  ( FIGS. 2 ,  3 ,  5 , and  6 ) may be inserted through bore  34  ( FIG. 3 ) such that, as described further below, male hex end feature  86  of driver  38  matingly engages female hex end feature  88  of threaded rod  64  disposed in body portion  32  of surgical instrument  20 . 
         [0039]    When instrument  20  is secured to hip stem prosthesis  22 , as described below, and driver  38  is removed from bore  34  of surgical instrument  20 , surgical instrument  20  is usable as an impactor. Particularly, surgical instrument  20  includes impaction head  36  rigidly connected by body portion  32  to impaction portion  40 . When driver  38  is disengaged from instrument  20 , an impaction force applied on impaction head  36  translates along rigid body portion  32  to impaction portion  40 . As impaction portion  40  is engaged with proximal body portion  25  of hip stem prosthesis  22 , as described below, force is then translated from impaction portion  40  of instrument  20  to proximal body portion  25  of hip stem prosthesis  22 . This force transmission allows for the impaction and seating of prosthesis  22  into a proximal femur (not shown), for example. 
         [0040]    Surgical instrument  20  includes first engagement portion  40  projecting from body portion  32 . First engagement portion  40  may be, for example, an impaction portion including a tip for receipt into impaction feature  42  on a top surface of proximal body portion  25 . Impaction feature  42  may be, for example, an indent or a recess configured to receive the tip of impaction portion  40 . 
         [0041]    Surgical instrument  20  further includes second engagement portion  44  which may be, for example, a clamping portion that is movable with respect to body portion  32 . Clamping portion  44  includes annular engagement member or collar  46  for engagement beneath head component  28  of hip stem prosthesis  22  and, in particular, for engagement with tapered relief section  30  of neck portion  26  of prosthesis  22 . 
         [0042]    Referring to  FIGS. 2 and 7 , impaction portion  40  is shown received into indent  42  in a top surface of proximal body portion  25 , and clamping portion  44  is shown engaging tapered relief section  30  beneath head region  28  of hip stem prosthesis  22 . Clamping portion  44  is connected to body portion  32  via actuation assembly  45  which includes yoke assembly or linkage assembly  48 , adjustment block  60  ( FIG. 3 ), and threaded rod  64  ( FIG. 3 ). Linkage assembly  48  of actuation assembly  45  forms a type of four-bar linkage between clamping portion  44  and adjustment block  60 . 
         [0043]    Referring to  FIGS. 5 and 6 , linkage assembly  48  includes link lever  50  connected to two Y-shaped arms  52 ,  54 . Each Y-shaped arm includes a lower bar from which two forked upper bars extend as prongs to create the Y-shape. Link lever  50  includes two opposing elongate plates  50 A,  50 B which project from top surface  56  of clamping portion  44  and are rotatably connected via pins  58  to upper Y-shaped arm  52  and lower Y-shaped arm  54 . Pins  58  are received through apertures (not shown) extending through respective lower bars of arms  52 ,  54  and through plates  50 A,  50 B of link lever  50 . 
         [0044]    Upper arm  52  and lower arm  54  are pivotally connected to adjustment block  60  ( FIGS. 3-6  and  13 ) via pins  62 . Adjustment block  60  is exposed and accessible through slots defined by walls on opposite sides of body portion  32 . Pins  62  are received through apertures (not shown) extending through upper bars of arms  52 ,  54  and through block  60 . Adjustment block  60  is threadably connected to and longitudinally displaceable along threaded rod  64  ( FIGS. 3-6  and  13 ), as described further below.  FIG. 4  shows a view of the attachment of instrument  20  of this disclosure to hip stem prosthesis  22  with impaction portion  40  engaged with proximal body portion  25  of hip stem prosthesis  22  and clamping portion  44  clamping tapered relief portion  30  beneath head region  28  of neck portion  26  of hip stem prosthesis  22 . 
         [0045]    Referring back to  FIGS. 5 and 6 , a distal end of threaded rod  64  is received within bushing  35 , which is disposed within a distal end wall partially defining bore  34  of surgical instrument  20 . At a proximal end, female hex end feature  88  of threaded rod  64  includes annular groove  37  that receives pins  39  disposed within internal walls defining bore  34 . With the above-described structure, threaded rod  64  is substantially prevented from axial displacement about longitudinal axis S of surgical instrument  20  while still being able to rotate about longitudinal axis S. 
         [0046]    Referring to  FIG. 8 , clamping portion  44  includes front portion  65  including collar  46 . Clamping portion  44  also includes rear portion  66  having second internal wall or rear wall  68  projecting transversely from collar  46 . With collar  46  of clamping portion  44  received about tapered relief portion  30  of hip stem prosthesis  22 , as shown in  FIG. 8 , rear wall  68  of rear portion  66  can contact head region  28  along at least two contact surfaces of rear wall  68  which, as shown herein, may be generally linear contact surfaces. For example, referring to  FIGS. 9 and 10 , the contact surfaces of rear wall  68  which contact head region  28  are shown as contact surface  70 A and contact surface  70 B. 
         [0047]    The combination of the engagement of collar  46  of clamping portion  44  against tapered relief portion  30  of head region  28  and the contact of the two substantially flat surfaces  70 A,  70 B of rear wall  68  of clamping portion  44  with head region  28  allow for opposing clamping forces when instrument  20  is attached to prosthesis  22 , as described further below. The opposing clamping forces prevent rocking of head region  28  within clamping portion  44  and provide rotational control of hip stem prosthesis  22  via surgical instrument  20 . 
         [0048]      FIG. 10  illustrates another embodiment of clamping portion  44  with prosthesis  22  shown in phantom. Clamping portion  44  does not include a V-shaped rear wall  68  but rather includes a more arcuately shaped rear wall. Rear wall  58  of  FIG. 10  still includes contact surfaces  70 A,  70 B, though the surfaces are not shown to completely extend to a top of rear wall  68  (as shown in  FIG. 9 ). Additionally, while contact surfaces  70 A,  70 B are generally indicated in the drawings, such exact lines may not be visually identifiable and marked in an actual surgical instrument  20 . 
         [0049]    In an alternative embodiment, as shown in  FIGS. 11A and 11B , contact surfaces  70 A,  70 B ( FIGS. 9 and 10 ) of rear wall  68  are formed by inserts ( FIG. 11B ) that may be metallic or non-metallic inserts. Inserts  72  may be, for example, plastic inserts. As shown in  FIG. 11B , inserts  72  are inserted or molded into channels  74  ( FIG. 11A ) within rear wall  68  of clamping portion  44 . 
         [0050]    Referring back to  FIG. 4 , surgical instrument  20  is shown attached to hip stem prosthesis  22  via attachment of impaction portion  40  and clamping portion  44  to hip stem prosthesis  22 , as described above. Via actuation assembly  45 , clamping portion  44  may adjustably connect to either a first neck portion of a first hip stem prosthesis or a second neck portion of a second hip stem prosthesis that has a different offset and/or leg length dimension than the first hip stem prosthesis. 
         [0051]      FIGS. 12A-12D  illustrate how clamping portion  44  is attached to neck portion  26  of hip stem prosthesis  22 . As shown in  FIG. 12A , collar  46  of clamping portion  44  includes bore  76  extending from proximal surface  78  ( FIGS. 9-10 ) to distal surface  80  ( FIGS. 12A-12B ) and formed by first internal wall or tapered relief wall  47  of collar  46 . Prior to engaging impaction portion  40  of surgical instrument  20  with indent  42  of hip stem prosthesis  22 , clamping portion  44  is first inserted over head region  28  such that head region  28  is loosely received in bore  76  of clamping portion  44 . As shown in  FIG. 12B , clamping portion  44  rotates about pins  58  on link lever  50  with respect to arm  52  ( FIG. 4 ) and arm  54  ( FIG. 12B ) to which they are connected to downwardly position clamping portion  44  over head region  28  of hip stem prosthesis  22 . In particular, collar  46  is pushed downward towards tapered relief portion  30  of neck portion  26  of hip stem prosthesis  22  beneath head region  28  and between head region  28  and proximal body portion  25 . 
         [0052]    As shown in  FIG. 12C , front portion  65  of clamping portion  44  includes tapered relief wall  47  of annular collar  46  that is shaped to abut against and clamp tapered relief portion  30  of neck portion  26 .  FIG. 12D  shows clamping portion  44  engaged with tapered relief portion  30  of neck portion  26  of hip stem prosthesis  22 . With surgical instrument  20  secured to prosthesis  22 , head region  28  will also contact surfaces  70 A,  70 B ( FIGS. 9 and 10 ) of rear wall  68  of clamping portion  44 . If impaction portion  40  is disengaged from indent  42 , clamping portion  44  may be removed from neck portion  26  by reversing the steps of insertion. For example, tapered relief wall  47  may be rotated away from contact with head region  28  and clamping portion  44  may be pulled away from and over head region  28  while tapered relief wall  47  clears head region  28  to allow for the withdrawal of clamping portion  44 . 
         [0053]    Pins  58  and  62  of this disclosure are rotatable within the apertures through which they are received as they may have an outer diameter that is less than the inner diameter of the respective apertures. Arms  52  and  54 , for instance, may move and rotate about pins  62  connecting arms to block  60 . As arms  52 ,  54  rotate about pins  62  and move with respect to adjustment block  60 , link lever  50  additionally rotates about pins  58  connecting arms  52 ,  54  to link lever  50  in a similar manner. Particularly, as these pins are also rotatable, link lever  50  will rotate about pins  58  to move with respect to arms  52 ,  54  and thus clamping portion  44 , integral with link lever  50 , will move with respect to arms  52 ,  54  and body portion  32  of instrument  20 . 
         [0054]    As discussed above,  FIG. 3  illustrates an exploded view of surgical instrument  20  where driver  38  is not yet inserted into body portion  32  of surgical instrument  20 . Driver  38  includes handle end  82 , rod  84  projecting from handle end  82 , and male hex end feature  86 . Male hex end feature  86  is configured to engage with mating female hex end feature  88  disposed at a top, proximal end of threaded rod  64 . As shown in  FIG. 5 , when driver  38  is inserted into bore  34  of instrument  20  to substantially extend a majority of the length of body portion  32 , male hex end feature  86  is disposed above female hex end feature  88 . Male hex end feature  86  will be inserted into female hex end feature  88  until the hex end features  86  and  88  are matingly engaged, as shown in  FIG. 6 . Upon such engagement, driver  38  may be rotated in the direction of arrow A ( FIG. 6 ), which causes a corresponding rotation of threaded rod  64 . The rotation of threaded rod  64  will cause translation of adjustment block  60  that is constrained against rotation about and threadably engaged to threaded rod  64 . For example, should the rotation occur in a clockwise direction, block  60  will translate upward on threaded rod  64 . Should the rotation occur in a counter-clockwise direction, block  60  will translate or move in a downwards direction on the threaded rod  64 . 
         [0055]    Referring to  FIGS. 6 and 12A , when driver  38  is rotated in a selected direction, such as in the direction of arrow A ( FIG. 6 ), adjustment block  60  will move longitudinally with respect to threaded rod  64 . As further described below, when impaction portion  40  is received within indent  42 , rotation of driver  38  in a clockwise direction will allow impaction portion  40  to tightly anchor to and be seated within indent  42  of proximal body portion  25 . A counter-clockwise rotation will allow for impaction portion  40  to be loosened from such an engagement and to eventually be removed from indent  42 . 
         [0056]    A surgeon may position impaction portion  40  away from hip stem prosthesis  22  while loosely engaging clamping portion  44  to head region  28 , as described above. The surgeon may then adjust impaction portion  40  until it is substantially aligned with indent  42 . Particularly, a surgeon adjusts impaction portion  40  towards indent  42 . If adjustment block  60  is positioned in a first position with respect to threaded rod  64 , however, the surgeon may not be able to effect such an alignment of impaction portion  40  and indent  42  while clamping portion  44  is loosely engaged to neck portion  46  of hip stem prosthesis  22 . The surgeon will then adjust adjustment block  60  to a desired position via driver  38 , as described above, which is a position determined by trial and error by the surgeon, until the surgeon is able to align impaction portion  40  to be loosely received into indent  42  of hip stem prosthesis  22 . 
         [0057]    Via rotation of driver  38  in the direction of arrow A ( FIG. 6 ), and described above, corresponding rotation of threaded rod  64  allows impaction portion  40  to be finally seated and anchored within indent  42 , to provide a fixed, anchoring point while simultaneously actuation assembly  45  causes clamping portion  44  to tilt about tapered relief wall  47 , urging rear wall  68  into engagement with head region  28 , as described above. Particularly, as driver  38  is rotated clockwise, adjustment block  60  translates upwards, causing clamping portion  44  via actuation assembly  45 , as described above, to be urged upwards against a distal surface of head region  28 . Simultaneously, a downwards reaction force presses impaction portion  40  against distal wall  43  forming indent  42 . While clamping portion  44  is being urged upwards against head region  28 , it is also tilting inwardly towards body portion  32  of surgical instrument  20 , causing opposing reaction forces that are transverse to axis S of surgical instrument  20  to occur against the contact points of neck portion  26  (namely along tapered relief wall  47  and contact surfaces  70 A and  70 B) and clamping portion  44  to firmly press clamping portion  44  to neck portion  26  of prosthesis  22 . The resultant forces, as described above, act as binding forces to secure surgical instrument  20  against hip stem prosthesis  22 . 
         [0058]    Referring to  FIG. 13 , an overall operation of surgical instrument  20  will be described. Particularly,  FIG. 13  is a schematic representation illustrating the attachment of surgical instrument  20  to a first hip stem prosthesis  22 A (shown in solid lines) and to an alternative second hip stem prosthesis  22 B (shown in dashed lines). Second hip stem prosthesis  22 B is a prosthesis having a longer leg length dimension and a larger offset dimension than first hip stem prosthesis  22 A. 
         [0059]    First hip stem prosthesis  22 A includes head center HC 1  horizontally spaced from longitudinal axis L, as shown via dimension D 1 . Head center HC 1  intersects neck axis N 1  of neck portion  26 A of first hip stem prosthesis  22 A. 
         [0060]    Second hip stem prosthesis  22 B includes head center HC 2  horizontally spaced from longitudinal axis L, as shown via dimension D 2 . Head center HC 2  intersects neck axis N 2  of neck portion  26 B of second hip stem prosthesis  22 B. 
         [0061]    Dimensions D 1  and D 2  depict the different respective offset dimensions of prostheses  22 A and  22 B. Prostheses  22 A and  22 B also have different leg length dimensions, which is indicated by head center HC 2  of second hip stem prosthesis  22 B being vertically spaced from head center HC 1  of first hip stem prosthesis  22 A at a distance shown as dimension V 1 . Moreover, indents  42 A,  42 B may be disposed in substantially the same location on the differently sized hip stem prostheses  22 A,  22 B and in substantial alignment with longitudinal axis L of each prosthesis. 
         [0062]    The attachment of surgical instrument  20  to either first hip stem prosthesis  22 A or second hip stem prosthesis  22 B is described below. As described above, clamping portion  44  will loosely attach to neck portion  26 A of first hip stem prosthesis  22 A or neck portion  26 B of second hip stem prosthesis  22 B before impaction portion  40  is seated within respective indent  42 A,  42 B of the selected prosthesis. A surgeon may bring axis S of surgical instrument  20  into substantial alignment with axis L of the selected hip stem prosthesis  22 A or  22 B, through a trial and error method as described above that may require the surgeon to adjust the position of adjustment block  60  via driver  38 . The surgeon then uses driver  38 , as described above, to seat impaction portion  40  within respective indent  42 A or  42 B. 
         [0063]    When clamping portion  44  is attached to first neck portion  26 A of first hip stem prosthesis  22 A and impaction portion  40  is moved into substantial alignment with indent  42 A, block  60  has generally been adjusted by the surgeon to position P 1  (shown in solid lines). Alternatively, when clamping portion  44  is attached to second neck portion  26 B of second hip stem prosthesis  22 B and impaction portion  40  is moved into substantial alignment with indent  42 B, block  60  has generally been adjusted by the surgeon to position P 2  (shown in dashed lines). The further that clamping portion  44  horizontally and/or vertically extends to accommodate respective offset and leg length dimensions, the lower block  60  will tend to be positioned with respect to threaded rod  64  when impaction portion  40  is brought into substantial alignment with the indent of the selected hip prosthesis. 
         [0064]    When surgical instrument  20  is secured to the selected hip component  22 A or  22 B, as described above, the surgeon using the instrument is provided with substantially 360° of rotational control such that the surgeon may insert selected prosthesis  22 A or  22 B with substantial ease through multiple locations on the leg or body of a patient. For example, the surgeon may now insert the prosthesis through a posterior incision on the body of the patient, rather than an anterior incision, and then rotate the prosthesis into the desired orientation and position such that the prosthesis may be properly inserted into a prepared opening within the proximal end of the femur. 
         [0065]    While this disclosure has been described as having exemplary designs, the present disclosure can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.