Abstract:
A modular femoral hip joint prosthesis can include a proximal femoral body having a distal end and a proximal end. The proximal end can be adapted to mate with a femoral head. A femoral stem can have a proximal section and a distal section. The femoral stem can be adapted to matingly connect with the distal end of the proximal femoral body. The proximal section can have a porous metal coating that is adapted to facilitate bony ingrowth. The distal section can have at least one spline formed along an outer surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit and priority of 61/310,865, filed Mar. 5, 2010. The entire disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates generally to femoral hip stems and more specifically to a modular femoral hip stem assembly that incorporates a distal stem having a proximal section that is porous coated and a distal tapered section that incorporates splines thereon. 
       BACKGROUND 
       [0003]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0004]    In some examples of femoral revision surgery, it may be required to repair a fractured or osteotomized femur around a seated femoral implant, such as by using cables or other known mechanical fixation. In one example, a surgeon can distally pot a femoral hip stem into an intact distal femur and subsequently wrap the non-intact proximal femur around the proximal portion of the femoral hip stem. 
       SUMMARY 
       [0005]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0006]    A modular femoral hip joint prosthesis can include a proximal femoral body having a distal end and a proximal end. The proximal end can be adapted to mate with a femoral head. A femoral stem can have a proximal section and a distal section. The femoral stem can be adapted to matingly connect with the distal end of the proximal femoral body. The proximal section can have a porous metal coating that is adapted to facilitate bony ingrowth. The distal section can have at least one spline formed along an outer surface. 
         [0007]    According to additional features, the proximal section of the femoral stem can extend along a first axis and the distal section of the femoral stem can extend along a second axis. The first and the second axes can be non-parallel. The distal section of the femoral stem can taper toward a distal tip. The first and second axes can extend at an angle substantially between 2° and 10°. In one example, the angle can be 5°. The proximal section of the femoral stem can include a male taper end. The distal end of the proximal femoral body can include a female taper. The male taper end of the femoral stem can be adapted to be received in the female taper of the proximal femoral body. According to additional features, the modular femoral hip prosthesis can further comprise a fastener that is operable to extend into an opening in the proximal femoral and threadably mate with a threaded bore formed on the male taper end of the femoral stem. 
         [0008]    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 
         [0009]    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. 
           [0010]      FIG. 1  is a perspective view of an exemplary modular femoral hip joint prosthesis constructed in accordance to one example of the present teachings and shown in an assembled position; 
           [0011]      FIG. 2  is an exploded perspective view of the modular femoral hip joint prosthesis shown in  FIG. 1 ; and 
           [0012]      FIG. 3  is a medial view of the modular femoral hip joint prosthesis shown cooperating with a cerclage fixation assembly in an implanted position according to one example of the present teachings. 
       
    
    
       [0013]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0014]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0015]    With initial reference to  FIG. 1 , a modular femoral hip joint prosthesis constructed in accordance to one example of the present teachings is shown and generally identified at reference numeral  10 . The modular femoral hip joint prosthesis can generally comprise a distal stem  12 , a proximal femoral body  14 , and a femoral head  16 . As will be described herein, the distal stem  12 , proximal femoral body  14 , and the femoral head  16  can all be modular components that may be selectively attached to each other during a surgical procedure, such as a femoral revision procedure. In this regard, each of the distal stem  12 , the proximal femoral body  14  and the femoral head  16  can comprise a plurality of unique components having various dimensions that may be suitable for a particular patient. As such, a surgeon may have a kit of components including various distal stems, proximal femoral bodies and femoral heads all having various dimensions and features that the surgeon can intraoperatively select according to a patient&#39;s particular need. 
         [0016]    With continued reference to  FIG. 1  and additional reference now to  FIG. 2 , the modular femoral hip joint prosthesis  10  will be further described. The distal stem  12  can include a proximal section  20  and a distal section  22 . A male taper end  24  can extend from the proximal section  20 . The male taper end  24  can generally define a blind threaded bore  26  formed therein. The proximal section  20  can generally be formed along a first axis  30 . The distal section  22  can be generally formed along a second axis  32 . In one example, a small angled transition section  33  ( FIG. 1 ) may be formed between the proximal section  20  and the distal section  22 . The respective first and second axes  30  and  32  can form an angle  34  relative to each other. The angle  34  can be any suitable angle such as between 2° and 10° for example and more specifically about 5°. 
         [0017]    It is contemplated that a series of stems  12  can be provided that may each define a distinct angle  34 , such that a surgeon can select the appropriate stem  12  having an angle that is best suited for a particular patient&#39;s needs. Moreover, each distal stem  12  can have distinct lengths. It is also contemplated that the respective lengths of the proximal section  20  and distal section  22  may vary. It can also be appreciated that while the proximal section  20  and distal section  22  have been described as having respective long axes  30  and  32 , respectively, that the proximal section  20  and the distal section  22  can form a continuous bowed section where one or both of the proximal section  20  and distal section  22  form a curved profile. 
         [0018]    The proximal section  20  may be coated with porous material  38 , such as, but not limited to, Regenerex® offered by Biomet, Inc., of Warsaw, Ind. Other porous materials can include plasma spray, grit blasting, etc. The porous material  38  covers substantially all of the proximal section  20  from the male taper end  24  to the start of the distal section  22 . The distal section  22  can include a plurality of longitudinally extending splines or flutes  40  positioned radially about the distal section  22 . The distal section  22  can be tapered from (or near) its transition from the proximal section  20  to a distal tip  42 . The distal section  22  can also be slotted. A surface of the distal section  22  can be roughened such as by grit blasting. The stem  12  can be formed of a rigid biocompatible material, such as titanium for example. Other materials are contemplated. The stem  12  can be particularly suitable for providing favorable characteristics when implanted into an intramedullary (IM) canal  84  ( FIG. 3 ) of a femur. In this regard, the stem  12  can utilize mechanical fixation with the tapered splines  40  to inhibit rotation and subsidence of the stem  12 . Furthermore, the proximal section  20  of the stem  12  can incorporate porous coating  38  to encourage bony ingrowth for biologic fixation of the non-intact portion of the femur to heal into. 
         [0019]    The proximal femoral body  14  can generally include a neck  44  that has a proximal end  46  including a male taper  48 . The proximal femoral body  14  can further include a distal end  50  that has a bore  52 . The bore  52  can include a female taper  54 . The male taper  48  of the proximal end  46  can be configured to mate with a female taper  60  provided in the femoral head  16 . In one example, the male taper  48  can mate with the female taper  60  as a Morse taper connection. It will be appreciated that in other examples, the male taper may be formed on the proximal femoral body  14  and the female taper formed on the stem  12 . A threaded portion  64  can be formed in an opening  66  on the proximal femoral body  14 . 
         [0020]    Assembling the stem  12  with the proximal femoral body  14  according to one example will now be described. The male taper end  24  of the stem  12  can be inserted into the female taper  54  of the proximal femoral body  14 . Further advancement of the male taper end  24  into the female taper  54  can encourage a Morse taper connection or taper-fit connection. A fastener  70  can optionally be advanced into threaded engagement with the blind threaded bore  26  of the male taper end  24  on the stem  12  to further encourage the male taper end  24  to be drawn into the female taper  54 . 
         [0021]    With additional reference now to  FIG. 3 , the modular femoral hip joint prosthesis  10  will be described in an implanted position within the IM canal  84  of a femur  74 . The femur can have one or many fractures, such that portions of the femur  74  are generally intact and other portions are disconnected from adjacent bone. 
         [0022]    In the exemplary configuration, the modular femoral hip joint prosthesis  10  can cooperate with a cerclage fixation assembly  78  that includes a plate  80  and a plurality of cables or monofilament wires  82 . In one example, the plurality of cables or monofilament wires  82  can be wrapped around portions of the intact and non-intact portions of the femur  74 . As explained, the femur  74  can have a fracture or series of fractures that may result in the femur  74  as collectively including one or a plurality of larger bone fragments, as well as one or a plurality of smaller bone fragments. It will be appreciated that in some examples, the surgeon may prepare the IM canal  84  of the femur  74  for receipt of the modular femoral hip joint prosthesis  10 . Additional details of one exemplary method of preparing the femur  74  may be found in commonly owned and copending U.S. patent application Ser. No. (Attorney Docket No. 5490-000797) entitled “Method and Apparatus for Implanting a Modular Femoral Hip” filed concurrently herewith, which is hereby expressly incorporated herein by reference. 
         [0023]    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.