Patent Publication Number: US-2010114326-A1

Title: Modular implant for joint prosthesis

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of orthopaedic implants, and in particular, to a modular prosthesis for use in conjunction with partial or total joint replacement procedures, such as humeral and femoral replacement and reconstruction. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 7,445,638, the entirety of which is incorporated herein, describes humeral implants that include three separate elements: anchoring stem; a support unit; and one of a cap-shaped humeral head insert or a cup shaped insert, depending on whether partial, full or reverse shoulder reconstruction is required. The stem, which is inserted in the medullary canal of the humerus, is used in conjunction with the support unit to ensure stabilization of the support unit, which, when properly stabilized, functions to anchor the humeral head implant in the humerus. 
     There are, however, some drawbacks associated with the prior art, and it would be desirable to overcome these drawbacks in order to improve the process and results associated with joint prostheses, particularly those for shoulders and hips. 
     One drawback associated with the prior art is that after the support unit is impacted in the resected humerus, the upper end of the neck that mates with the humeral head (cap or cup) insert protrudes from the surface that is otherwise flush with respect to the resected humerus. The protruding shaft part occludes the surgeon&#39;s access to the glenoid cavity, and its presence can impede the surgeon&#39;s progress with respect to other portions of the implantation process in the glenoid region before the humeral insert (cap or cup) is finally impacted thereon. It would be desirable to provide as much clearance as possible for the surgeons during the implantation process while maintaining the ability to facilitate a secure and reliable connection between the support unit and the humeral insert. 
     It would also be desirable to reduce the number of modular components needed for the prosthetic unit, and it would be particularly desirable to eliminate the need for the stem part traditionally implanted, for example in the medullary canal of the humerus (in shoulder applications) or the femoral canal (in hip applications). 
     It is an object of the present invention to improve implantation technology and the implantation process, and to overcome the drawbacks associated with prior art joint prostheses. 
     SUMMARY OF THE INVENTION 
     The present invention achieves its objectives by providing cooperating modular prosthetic components that do not occlude the surgeon&#39;s access to other adjacent areas that require reconstruction and by reducing the number of modular components required overall. According to the present invention, this is accomplished without sacrificing the stability of the implant by virtue of the modified structure of the support unit, whose structure promotes bony ingrowth into porous portions of the support unit for secure fixation of the prosthetic joint in the humerus that can be used with, or preferably without a traditional stem part. 
     The present invention provides, in particular, a support cleat unit for use in conjunction with modular prosthesis units for partial, reverse or total joint reconstruction. 
     According to one embodiment of the present invention, a modular prosthetic implant is provided, comprising a support cleat unit having a seat portion, which is preferably circular, and having an overall shape delimited by an imaginary domed surface, which is preferably substantially hemispherical in shape with a circular base shape, but which also includes dome shapes having an oblong or oval base shape or the like, as needed for use in connection with the physiological requirements of a particular type of joint. The support cleat unit comprises a centrally located cylindrical body portion extending from a first end toward an opposed second end thereof, and which has a central axis and a hole concentric with the central axis. The hole extends from a first opening in the first end of the cylindrical body portion toward the second end of the cylindrical body portion, and has a least a first section whose diameter defines a female Morse taper adapted to receive a male member having a corresponding Morse taper. 
     The support cleat unit also comprises a plurality of arched appendages integral with the cylindrical body portion. The arched appendages are radially spaced apart from one another and extend radially outwardly from an outer circumferential surface of the cylindrical body portion so that outer surfaces of the arched appendages delimit a skeleton of the imaginary overall dome shape of the support cleat unit. The support cleat unit according to the present invention can be made of any suitable bio-compatible materials, examples of which include, but are not limited to titanium, cobalt, stainless steel and polyether ether ketone (PEEK). 
     According to one aspect of the present invention, a thickness (or width) of each arched appendage increases from the base portions thereof toward terminal ends thereof, so as to define an outwardly increasing tapered thickness that is greater at the terminal ends of said arched appendages than at the base portions thereof [see, e.g.,  FIGS. 9A-9D ]. According to yet another aspect, the thickness/width of each arched appendage decreases from the base portions thereof toward terminal ends thereof, so as to define an outwardly decreasing tapered thickness that is less at the terminal ends of said arched appendages than at the base portions thereof [see, e.g.,  FIGS. 10A-10D ]. 
     According to one aspect of the present invention, the hole in the cylindrical body portion comprises a through hole extending from the first opening in the first end thereof toward an opposed second opening in the second end (seat) thereof. The first section of the hole has a terminal end spaced a distance apart from the second end of the cylindrical body, and the terminal end of the first section has an opening with a diameter that is smaller than a diameter of the first opening so as to define an inner seat. The opening of the terminal end of the first section communicates with a second section of the through hole extending from the opening of the terminal end of the first section toward the second opening at the second end of the cylindrical body portion. Preferably, at least a portion of the second section of the through hole is threaded. 
     According to another aspect of the present invention, the support cleat unit further comprises a cap member adapted to threadedly engage at least a portion of the second section of the through hole proximate the second end of the cylindrical body portion so as to cover the opening at the second end of the cylindrical body portion and essentially define the seat of the cylindrical body portion. 
     According to another embodiment of the present invention, a plurality of porous metal portions defining fin-like extensions are provided between the outer circumferential surface of the cylindrical body portion and an upper/inner surface of each arched appendage [see, e.g.,  FIG. 2A ]. The porous metal should be a bio-compatible metal, suitable examples of which include, but are not limited to porous titanium, titanium alloy and tantalum. 
     According to another embodiment of the present invention, the support cleat unit further comprises a porous metal coating provided on at least a portion of the outer circumferential surface of the cylindrical body portion. Preferably, the porous metal coating is also provided on surfaces of the arched appendages. The porous metal coating can be any suitable bio-compatible porous metal coating, such as a cobalt or titanium coating, and can be applied in any known manner, such as plasma spraying. 
     According to yet another aspect, the porous metal coating covers substantially all of the outer surface of the cylindrical body portion and covers substantially all surfaces of the arched appendages, with the exception of a portion of the outer/lower surfaces thereof [see, e.g.,  FIGS. 2B-2C ]. 
     According to another embodiment of the present invention, terminal ends of each of the arched appendages further comprise a foot member extending radially outwardly with respect to the central axis of the cylindrical body portion [see, e.g.,  FIG. 3 ]. According to one aspect, an upper surface of each foot member is flush with a surface of the first end of the cylindrical body portion. 
     This integral structure can be accomplished by machining the appendages from a bowl-shaped support cleat unit pre-form, or via the initial mold design. These processes would be readily understood by one skilled in the art. 
     According to yet another embodiment of the present invention, the terminal ends of each of the arched appendages are connected to one another via a rim circumscribing or otherwise surrounding the cylindrical body portion [see, e.g.,  FIG. 4 ]. According to one aspect, an upper surface of the rim is flush with the surface of the first end of the cylindrical body portion. 
     According to another embodiment of the present invention, the modular implant further comprises an insert unit adapted to cooperate with a joint cavity of a patient. For example, in the case of a humeral implant, the insert unit would cooperate with the native glenoid cavity of a patient or a glenoid implant. However, it should be understood that the present invention is not strictly limited to humeral implants. The insert unit comprises a male member having a Morse taper corresponding to the female Morse taper of the first section of the hole in the cylindrical body portion of the support unit. 
     According to one aspect of the present invention, the thickness of each arched appendage increases from the base portions thereof toward terminal ends thereof, so as to define an outwardly increasing tapered thickness that is greater at the terminal ends of the arched appendages than at the base portions thereof. 
     According to another aspect of the present invention, the thickness of each the arched appendage decreases from the base portions thereof toward terminal ends thereof, so as to define an outwardly decreasing tapered thickness that is less at the terminal ends of the arched appendages than at the base portions thereof. 
     According to one aspect of the present invention, a porous metal coating is provided on at least a portion of the outer circumferential surface of the cylindrical body portion and substantially all surfaces of the arched appendages. According to another aspect, the porous metal coating covers substantially all of the outer surface of the cylindrical body portion and covers substantially all surfaces of the arched appendages. According to yet another aspect, the porous metal coating on the arched appendages includes a plurality of barbed structures formed thereon 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of a support cleat unit according to one embodiment of the present invention,  FIG. 1B  is a top plan view of the support unit shown in  FIG. 1A ,  FIG. 1C  is a bottom plan view of the support unit shown in  FIG. 1A , and  FIG. 1D  is a cross-sectional view taken through line A-A in  FIG. 1A .  FIG. 1E  is a perspective view of another support cleat unit according to the present invention, and  FIG. 1F  is a cross-sectional view of the support cleat shown in  FIG. 1E , showing an internal structure of the cylindrical body portion that is different from that shown and described in connection with  FIGS. 1A-1D . 
         FIG. 2A  is a perspective view of a support cleat unit including a porous metal fin structure unit according to one aspect of the present invention, and  FIGS. 2B and 2C  are a front view and a perspective view, respectively, of a support unit having a different porous metal coating structure according to another aspect of the present invention. 
         FIG. 3  is a perspective view of a support cleat unit according to another embodiment of the present invention. 
         FIG. 4  is a perspective view of a support cleat unit according to another embodiment of the present invention. 
         FIGS. 5A and 5B  are views showing a modular prosthesis assembly, in the specific context of an example for shoulder prosthesis, including the support cleat unit shown in  FIG. 1A  and a male (cap) humeral head insert unit adapted to cooperate with the native glenoid cavity or reconstructed glenoid support. 
         FIGS. 5C-5E  are views showing a male (cap) humeral head insert unit having a male Morse taper shaft extending from the bottom surface thereof. In  FIGS. 5C and 5D , the axis of the shaft is concentric with the central axis of the cap portion. In  FIG. 5E , the axis of the shaft is eccentric with respect to the central axis of the cap portion. 
         FIG. 6  is an exploded view showing a modular shoulder prosthesis assembly including the support cleat unit shown in  FIG. 1A  and a female (cup) unit adapted to cooperate with a male (cap) glenoid implant (not shown). 
         FIGS. 7A-7C  show a support cleat unit according to another embodiment of the present invention utilized in conjunction with the hip in the case of a partial femoral head removal. 
         FIGS. 8A-8C  show a support cleat unit according to another embodiment of the present invention utilized in conjunction with the hip in the case of a total femoral head and neck removal. 
         FIGS. 9A-9D  are front and perspective views showing a support cleat unit including arched appendages having a tapered structure according to another aspect of the present invention, whereby the thickness of the terminal ends  31  of the arched appendages is greater than that of the base portions thereof that extend from the cylindrical body  2  proximate the second end  22  thereof. 
         FIGS. 10A-10D  are front and perspective views showing a support cleat unit including arched appendages having a tapered structure according to another aspect of the present invention, whereby the thickness of the terminal ends  31  of the arched appendages is less than that of the base portions thereof that extend from the cylindrical body  2  proximate the second end  22  thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1A  is a perspective view of a support cleat unit according to one embodiment of the present invention.  FIG. 1B  is a top plan view of the support unit shown in  FIG. 1A ,  FIG. 1C  is a bottom plan view of the support unit shown in  FIG. 1A , and  FIG. 1D  is a cross-sectional view taken through line A-A in  FIG. 1A .  FIG. 1E  is a perspective view of another support cleat unit according to the present invention, and  FIG. 1F  is a cross-sectional view of the support cleat shown in  FIG. 1E , showing an internal structure of the cylindrical body portion that is different from that shown and described in connection with  FIGS. 1A-1D . 
     The support cleat unit  1  includes a seat portion  22 , which is preferably circular, and has an overall shape delimited by an imaginary domed surface, which is preferably substantially hemispherical in shape with a circular base shape, but which also includes dome shapes having an oblong or oval base shape or the like, as dictated by the physiological requirements of a particular type of joint. The support cleat unit  1  comprises a centrally located cylindrical body portion  2  extending from a first end  21  toward an opposed second end  22  (e.g., the seat portion) thereof, and which has a central axis  231  and a hole  23  concentric with the central axis  231 . As shown in  FIGS. 1D and 1F , the hole  23  extends from a first opening  232  in the first end  21  of the cylindrical body portion  2  toward the second end  22  of the cylindrical body portion  2 , and has a least a first section  234  whose diameter defines a female Morse taper adapted to receive a male member having a corresponding Morse taper. 
     According to one aspect of the present invention, as shown in  FIG. 1D , the hole  23  in the cylindrical body portion  2  comprises a through hole extending from the first opening  232  in the first end  21  thereof toward an opposed second opening  233  in the second end (seat)  22  thereof. The first section  234  of the hole  23  has a terminal end  235  spaced a distance apart from the second end  22  of the cylindrical body  2 , and the terminal end  235  of the first section  234  has an opening  236  with a diameter that is smaller than a diameter of the first opening  232  so as to define an inner seat (at terminal end  235 ). The opening  236  of the terminal end  235  of the first section  23  communicates with a second section  237  of the through hole  23  extending from the opening  236  of the terminal end  235  of the first section  234  toward the second opening  233  at the second end  22  of the cylindrical body portion  2 . Preferably, at least a portion of the second section  237  of the through hole  23  is threaded. 
     For example, in  FIGS. 1B-1D , a threaded section  238  of the through hole  23 , having a smaller diameter than that of the first section  234  defining the reverse Morse taper, is provided at the second end of the cylindrical body portion  2 , which extends through the second end  22  thereof and has a dual purpose. One purpose of this feature is to facilitate the insertion of instrumentation for insertion during implantation and extraction, if necessary, of the support cleat unit. Another purpose is to facilitate means for affixing an end cap  55  (see, e.g.,  FIG. 5B ) onto the second end  22  of device. This type of end cap  55 , which may be made of a porous metal, such as REGENEREX®, or a porous coated metal, serves to prevent fluid and bone from entering into the device in situ and serves to anchor the device into the bone. Alternatively, traditional stem could be attached to the support unit at this location, as well. 
     The support cleat unit  1  also comprises a plurality of arched appendages  3  that are integral with respect to the cylindrical body portion  2 . The arched appendages  3  are radially spaced apart from one another and extend radially outwardly from an outer circumferential surface  20  of the cylindrical body portion  2  so that outer/lower surfaces  33  of the arched appendages delimit a skeleton of the imaginary overall dome shape of the support cleat unit  1 . 
       FIG. 2A  is a perspective view of a support cleat unit  12 A including a porous metal fin structure unit according to one aspect of the present invention. As shown in  FIG. 2A , a plurality of porous metal portions  4  defining fin-like extensions are provided and extend between the outer circumferential surface  20  of the cylindrical body portion  2  and an upper/inner surface  32  of each arched appendage  3 . The porous metal material must be a bio-compatible metal, suitable examples of which include, but are not limited to Regenerex®, porous titanium, titanium alloy and tantalum. Although it is not necessary to provide the porous metal extensions, the provision of the fin-like extension structure serves to help securely anchor the device into the bone and promote bone re-growth. 
       FIGS. 2B and 2C  are a front view and a perspective view, respectively, of a support cleat unit having a different porous metal coating structure according to another aspect of the present invention. As shown, the substantially the entire outer surface of the support cleat unit  12 B is coated with a thick porous metal material coating  4 , with the exception of portions of the outer surface of the first  21  and second  22  ends of the cylindrical body portion  2  and the outer/lower surfaces  33  of the arched appendages  3 . After the porous metal material  4  is provided on the support cleat unit  12 B as a substrate, the porous metal material is machined to have a corresponding shape and to define fin-like extensions between the arched appendages  3  and the cylindrical body portion  2 , covering the central portion of the cylindrical body portion  2  and nearly the entire surface of the arched appendages  3 , with the exceptions described above. Again, the provision of the porous metal material coated structure serves to help securely anchor the device into the bone and promote bony ingrowth. 
       FIGS. 9A-9D  are front and perspective views showing support cleat units  19 A and  19 B including arched appendages having a tapered structure according to additional aspects of the present invention, whereby the thickness or width of the arched appendages decreases toward the base so that the thickness of the covered terminal ends  31  of the arched appendages is greater than that of the base portions thereof that extend from the cylindrical body  2  proximate the second end  22  thereof. The advantages associated with this aspect of the present invention are as follows. 
     The outer diameter of the support cleat unit  19 A, as defined by the outermost surfaces of the arched appendages  3 , is smaller proximate the second end  22  of the cylindrical body portion  2  (the end of the device which is initially inserted into the prepared bone). Accordingly, the diameter of the portion of bone that is prepared to receive the implant can be smaller as well, and as the support cleat unit  19 A is impacted into the prepared bone, the increasing diameter provides additional compressive forces on the surrounding bone structure, creating a wedge-fit in the bone. This increased compressive force triggers a Wolfe&#39;s law response, whereby the bone reacts to the force by strengthening in that area, thereby improving the strength and bone regrowth in the implant area. 
     As shown, the outer surface of the support cleat units  19 A,  19 B are substantially entirely coated with a porous metal material coating  4 , as described above in connection with  FIGS. 2B and 2C , with the exception of portions of the first  21  and second  22  ends of the cylindrical body portion  2  and portions of the outer surfaces  33  of the arched appendages  3 , as described above. The provision of the porous metal coating  4  promotes bony ingrowth and aids in securely affixing the support cleat unit  19 A,  19 B in the resected portion of the respective bone (e.g., humerus or femur). The porous metal coating  4  on the arched appendages is machined to have a tapered structure corresponding to that of the underlying support unit substrate. 
     The main difference between the support cleat unit  19 A in  FIGS. 9A and 9B  and the support cleat unit  19 B in  FIGS. 9C and 9D  is that a plurality of notches defining a barbed structure  42  are machined into the outer surface of the porous metal material coated arched appendages in support cleat unit  19 B. The barbed structures  42  facilitate improved interdigitation between the resected bone and the arched appendages to further improve bone regrowth in conjunction with the implant. 
       FIGS. 10A-10D  are front and perspective views showing support cleat units  10 A and  10 B including arched appendages having a tapered structure according to another aspect of the present invention, whereby the thickness of the arched appendages increases toward the bases thereof, so that the thickness of the terminal ends  31  of the arched appendages is less than that of the base portions thereof that extend from the cylindrical body  2  proximate the second end  22  thereof. When this embodiment is used, the bone is prepared to accept insertion of the wider diameter portion of the support cleat unit  10 A,  10 B, and bone graft is packed into the slots in the portions of the prepared bone where the arched appendages become thinner to compensate for the smaller outer diameter of the support cleat unit  10 A,  10 B. Once bone is grown around the implant, the wider base of the appendages improves the stability and increases the pull-out strength. 
     As shown, the outer surfaces of the support cleat units  10 A,  10 B are also coated with the porous metal material coating  4 , as described above in connection with  FIGS. 2B and 2C  and  FIGS. 9A-9D . In addition, the barbed structure  42  is provided in conjunction with the outer surfaces of the coated arched appendages of the support cleat unit  10 B shown in  FIGS. 10C and 10D . 
     According to another embodiment, the support cleat unit includes a thinner porous metal coating  41  provided on at least a portion of the outer circumferential surface  20  of the cylindrical body portion  2  (see, e.g.,  FIG. 3 ). The provision of the porous metal coating  41  promotes bony ingrowth and aids in securely affixing the support cleat unit  1  in the resected portion of the respective bone (e.g., humerus or femur). This porous metal coating is provided as an alternative to the embodiment shown in  FIG. 2A , because plasma spraying an additional porous metal coating layer onto the REGENEREX® can block the pore structure and be counter effective. 
     Preferably, the porous metal coating  41  is also provided on surfaces of the arched appendages  3 . The porous metal coating  41  can be any suitable bio-compatible porous metal coating, such as REGENEREX®, a cobalt or a titanium coating, and can be applied in any known manner, such as plasma spraying. It is also possible to use a hydroxyapatite (HA) coating over the outer surfaces of the cylindrical body portion  2  and the arched appendages  3 . 
       FIG. 3  is a perspective view of a support cleat unit  13  according to another embodiment of the present invention. As shown, the terminal ends  31  of each of the arched appendages  3  include a foot member  34  extending radially outwardly with respect to the central axis of the cylindrical body portion. The upper surface  35  of each foot member  34  is flush or slightly lower than the surface  211  of the first end  21  of the cylindrical body portion  2 . 
     The provision of the foot members  34  serves as an anti-subsidence mechanism and contributes to ensuring that the support cleat unit  13  is securely implanted in the resected portion of the humerus or femur, for example. Since the foot members  34  are slightly lower than or substantially flush with respect to the upper surface  211  of the first end  21  of the cylindrical body portion  2 , the benefits described above remain attainable, and the foot members  34  do not obscure the implant site or hinder the surgeon&#39;s access to the necessary locations during the surgical implantation. 
       FIG. 4  is a perspective view of a support cleat unit  14  according to another embodiment of the present invention. As shown, the terminal ends  31  of each of the arched appendages  3  are circumferentially connected to one another via a rim  36  circumscribing or otherwise substantially surrounding the cylindrical body portion  2 . The upper surface  37  of the rim  36  is slightly lower than or substantially flush with the surface  211  of the first end  21  of the cylindrical body portion  2 . Like the embodiment shown in  FIG. 3 , the rim  36  structure provides an anti-subsidence mechanism, and the position of the rim surface  37  with respect to the upper surface  211  of the cylindrical body portion  2  (e.g., slightly lower than or flush) provides the benefits described above in a similar fashion. 
       FIGS. 5A and 5B  are views showing a modular prosthetic assembly including the support cleat unit shown in  FIG. 1A  and a male (cap) humeral head unit adapted to cooperate with the joint cavity, such as the glenoid cavity, or a reconstructed joint cavity support, such as a reconstructed glenoid support. One skilled in the art should readily appreciate that this structure could easily translate to relate to a hip implant.  FIGS. 5C-5E  are views showing a male insert unit  5  defining a humeral head unit having a cap portion  51  and a male Morse taper shaft  52  extending from the bottom surface  511  thereof. 
     In  FIGS. 5C and 5D , the axis of the Morse taper shaft  51  is concentric with a central axis of the cap portion  51  of the male head insert  5 . In  FIG. 5E , the axis of the shaft  51  is eccentric with respect to the central axis of the cap portion  51 . An adjustable humeral head having a male Morse taper shaft, such as that described in U.S. Pat. No. 6,492,699, the entirety of which is incorporated herein by reference, can also be used in conjunction with the support cleat units according to the present invention. 
     The head assembly disclosed in the &#39;699 patent includes a head and an adaptor. The adaptor is rotated to achieve a certain amount of offset between the head and the axis of the Morse taper. The ability to vary the degree of offset is desired so as to achieve complete coverage of the resected humerus, even in situations where the support unit is not centered in the resected surface of the humerus. 
     An end cap member  55  is also provided, which is adapted to threadedly engage at least a portion of the second section  237  (e.g., the threaded portion  238 ) of the through hole  23  proximate the second end  22  of the cylindrical body portion  2  so as to cover the opening  233  at the second end of the cylindrical body portion  2  and, in that case, essentially define the seat of the cylindrical body portion  2 . 
       FIG. 6  is an exploded view showing a modular prosthetic assembly including the support cleat unit  1  shown in  FIG. 1A  and a female (cup) unit  53  adapted to cooperate with a (cup)  54 . As explained above, with respect to a shoulder application, the support cleat unit  1  is impacted in the resected humerus, and an insert unit  51  is attached thereto which has a shape to replicate the humeral head (male) that articulates with the glenoid cavity, or a female cup-shaped cap  53  that articulates with a male cup implanted in the glenoid cavity. As mentioned above, however, the present invention is not strictly limited to shoulder joint applications, and can be used in conjunction with hip Arthroplasty, as explained in more detail below, or with other Arthroplasty applications, as needed. 
       FIGS. 7A-7C  and  8 A- 8 C illustrate methods for utilizing the support cleat unit  1  in the hip. In particular,  FIGS. 7A-7C  show a partial femoral head removal situation and  FIGS. 8A-8C  show a complete femoral head and neck removal. In both cases, these components could also be used in conjunction with an acetabular implant in total hip Arthroplasty (THA). 
     As shown in  FIG. 7A , a portion of the femoral head  703  is resected in a location shown, for example, by the line  705  representing the resection level, and after the required preparation through broaching or reaming, an appropriately sized support cleat unit is inserted into the femoral head  703  (see  FIG. 7B ). A hemispherical head implant unit  708  is then impacted onto the cleat, and which articulates with the acetabulum, using an impacting tool  706 , as shown in  FIG. 7C . Like the case with the shoulder, the head implant is made from an appropriate biocompatible material, such as a ceramic, metal, polyether ether ketone (PEEK), or the like. 
     With respect to the complete head and neck removal situation illustrated in  FIGS. 8A-C , the femoral head  703  and neck  702  are resected in  FIG. 8A  in a manner that is consistent with the procedure required in connection with current stemmed hip implants, and after proper preparation, the support cleat unit  1  is impacted into femur, as shown in  FIG. 8B . A femoral neck and head implant  709 , which can be a single implant component or a combination of separate implant components, and which articulates with the acetabulum, is then impacted onto the support cleat unit  1  to complete the replacement (see  FIG. 8C ). 
     According to the present state of the art, in order to perform a THA with current resurfacing devices, a large incision is required to allow access to the acetabulum. With all or part of the femoral head removed, which is made possible in connection with the support cleat according to the present invention, it is possible to ream the acetabulum through a smaller incision since the femoral head in not blocking the surgeon&#39;s view and access. This significant benefit can be readily appreciated as an important and valuable advancement with respect to both the surgical and healing processes. 
     As one skilled in the art can appreciate, the overall shape of the support cleat unit used in conjunction with hip applications should be slightly different than that described above in connection with shoulder applications, based on physiological constraints, and in order to properly fit the support basket into the resected femoral neck/femur and provide adequate stability. Suitable modifications may be made with respect to the number of arched appendages provided (e.g., 4 or 8) or with respect to the overall imaginary dome shape delimited by the arched appendages (e.g., an oval or oblong base, rather than circular, in hip applications). 
     Based on the foregoing descriptions, one skilled in the art should readily understand how to make, use and/or modify the support cleat unit described as needed for use in hip Arthroplasty. As noted, any such modifications would indeed be minimal, and no additional drawings are required to illustrate the number of different possibilities that are within the scope of the present invention.