Patent Application
20110257758
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.
This section provides background information related to the present disclosure which is not necessarily prior art.
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.
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 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.
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.
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.
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.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
With initial reference to
With continued reference to
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'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.
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 (
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.
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.
With additional reference now to
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.
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.
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.
| Number | Date | Country | |
|---|---|---|---|
| 61310865 | Mar 2010 | US |
