Patent Application
20240008991
The present invention relates generally to the field of prosthetic joints, and more particularly to a new and improved prosthetic hip replacement assembly, having a new and improved prosthetic ball component, which is to be utilized within hip replacement surgery.
Hip replacement is a commonly performed and very successful surgical procedure to rectify the pain and discomfort of hip arthritis. The most commonly utilized hip replacement assembly usually comprises four distinct components. As can best be appreciated from
Another conventional hip replacement assembly is disclosed within
Recently, a dual mobility hip replacement construct or assembly has been developed with the objective of effectively providing the ball or femoral head, fixedly connected to the proximal end of the femoral stem, with a larger overall ball head size or diameter so as to substantially decrease the risk of dislocation of the ball or femoral head from the acetabular shell and liner. As can best be appreciated from
As was the case with the single mobility hip replacement construct or assembly 10, once the highly porous coated acetabular shell 52 is inserted or implanted into the surgically prepared acetabulum, bone growth can occur organically and interface with the micro-pores of the highly porous coated acetabular shell 52. A metal liner 54, fabricated from a suitable metal material, is then inserted into and fixedly secured within the metal cup of the acetabular shell 52. A metal stem 56, that is, a femoral stem, is adapted to have its distal end fixedly inserted into a surgically prepared femur, while the opposite proximal end of the metal stem 56 is provided with an integrally formed trunnion or male morse taper 58. A metal or ceramic ball 60, which includes a female morse taper 62, is rigidly connected to the proximal end of the femoral stem 56 as a result of the mating of the male and female morse tapers 58,62, such as for example, by means of an interference fit, or the like. In addition, a plastic ball 64, which may be fabricated from a suitable thermoplastic material, such as, for example, polyethylene, and which has a diametrical extent that is substantially greater or larger than that of the metal or ceramic ball 60, is snap-fitted over the metal or ceramic ball 60. It is to be noted that the metal or ceramic ball 60 is capable of fully pivoting or articulating within the larger plastic ball 64, and still further, the larger plastic ball 64 is, in turn, capable of fully pivoting or articulating within the metal acetabular liner 64, such pivotal or articulated movements providing the hip replacement construct or assembly with its dual mobility characteristics.
Unfortunately, it has been discovered that this dual mobility hip replacement construct or assembly 50 has led to some structural deficiencies which has caused the dual mobility hip replacement construct or assembly 50 to structurally fail, thereby causing significant problems for patients into which the dual mobility hip replacement construct or assembly 50 has been inserted or implanted. More particularly, there have been instances in which “intra-prosthetic” dislocation has occurred, that is, dislocation or separation of the smaller metal or ceramic ball 60 from the larger plastic ball 64. In addition, assembly of the smaller metal or ceramic ball 60 with the larger plastic ball 64 is required to be performed during the hip replacement surgical procedure, thereby requiring specialized equipment to be used during the surgical procedure which obviously requires the expenditure of additional time for completion of the surgical procedure. Still further, the metal composition utilized to fabricate the femoral stem 56 normally differs from the metal composition utilized to fabricate the smaller metal ball 60, or if the smaller metal ball 60 is fabricated from a suitable ceramic material, then obviously there is a difference in materials. For example, femoral stems are conventionally fabricated from a cobalt-chrome composition, stainless steel, tantalum, or titanium, while the smaller metal ball 60 may be fabricated from a cobalt-chrome composition or a ceramic material, it being noted that cobalt-chrome compositions can vary in their percentage content of either one of the cobalt and chrome components. In any case, these differences in materials comprising the fabrication of the femoral stem 56 and the smaller ball 60 can lead to galvanic corrosion or trunnionosis which is characterized as a total hip replacement arthroplasty failure.
Various prosthetic hip replacement assemblies have been developed over the years in order to address the foregoing and/or similar or related problems, however, none of them have been capable of doing so. In the interest of full disclosure, examples of such prior prosthetic hip replacement assemblies are disclosed within U.S. Pat. No. 11,285,007 which issued to Kavolus, II et al. on Mar. 29, 2022; United States Patent Application Publication 2017/0333192 which was published for Zhou et al. on Nov. 23, 2017; United States Patent Application Publication 2014/0094927 which was published for Weeden on Apr. 3, 2014; U.S. Pat. No. 8,357,205 which issued to Rahaman et al. on Jan. 22, 2013; United States Patent Application Publication 2006/025148 which was published for Bar-Ziv on Nov. 16, 2006; United States Patent Application Publication 2003/0120347 which was published for Steinberg on Jun. 26, 2003; United States Patent Application Publication 2002/0156536 which was published for Harris et al. on Oct. 24, 2002; U.S. Pat. No. 5,066,304 which issued to Crowninshield et al. on Nov. 19, 1991; U.S. Pat. No. 4,978,355 which issued to Frey et al. on Dec. 18, 1990; European Patent EP 0 768 066 which issued to Ernst et al. on Apr. 16, 1997; European Patent Application EP 1 582 182 which was published for Aux Epaules et al. on Oct. 5, 2005; Chinese Patent Application CN 105030378 which was published on Nov. 11, 2015; PCT Patent Application Publication WO 2016/183701 which was published for Zhu et al. on Nov. 24, 2016; PCT Patent Application Publication WO 2019/171158 which was published for Perez Nunez on Sep. 12, 2019; European Patent Application Publication EP 3 777 775 which was published for Melozzi on Feb. 17, 2021; and European Patent Application Publication EP 3 777 776 which was published for Melozzi on Feb. 17, 2021.
A need therefore exists in the art for a new and improved prosthetic hip replacement assembly. Another need exists in the art for a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems. Still another need exists in the art for a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, substantially decreasing the risk of dislocation of the femoral head from the acetabular shell and liner. Yet another need exists in the art for a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, substantially decreasing the risk of any intra-prosthetic dislocation which has been experienced with dual-mobility hip replacement constructs or assemblies. Still yet another need exists in the art for a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, significantly reducing the time required to complete the prosthetic hip replacement surgical procedure. Yet still another need exists in the art for a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, galvanic corrosion which may occur when different, incompatible metals are utilized to fabricate the femoral stem and the femoral ball or head. An additional need exists in the art for a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, trunnionosis, which is characterized as a total hip replacement arthroplasty failure.
An overall objective of the present invention is to provide a new and improved prosthetic hip replacement assembly. Another overall objective of the present invention is to provide a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems. Still another overall objective of the present invention is to provide a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, substantially decreasing the risk of dislocation of the femoral head from the acetabular shell and liner. Yet another overall objective of the present invention is to provide a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, substantially decreasing the risk of any intra-prosthetic dislocation which has been experienced with dual-mobility hip replacement constructs or assemblies. Still yet another overall objective of the present invention is to provide a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, significantly reducing the time required to complete the prosthetic hip replacement surgical procedure. Yet still another overall objective of the present invention is to provide a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, galvanic corrosion which may occur when different, incompatible metals are utilized to fabricate the femoral stem and the femoral ball or head. An additional overall objective of the present invention is to provide a new and improved prosthetic hip replacement assembly which resolves the aforenoted problems, such as, for example, trunnionosis, which is characterized as a total prosthetic hip replacement arthroplasty failure.
In accordance with the principles and teachings of the present invention, a new and improved prosthetic hip replacement assembly has been developed and is seen to comprise a highly porous coated acetabular shell which is fabricated as a metal cup having a highly porous coating formed thereon and which is adapted to be inserted into a surgically prepared acetabulum. In this manner, once the highly porous coated acetabular shell is inserted or implanted into the surgically prepared acetabulum, bone growth can occur organically and interface with the micropores of the highly porous coated acetabular shell. A metal liner, fabricated from a suitable metal and having a thickness dimension which is smaller than the conventional thermoplastic liner material, is then inserted into and fixedly secured within the metal cup of the acetabular shell. A metal stem, that is, a femoral stem, is adapted to have its distal end fixedly inserted into a surgically prepared femur, while the opposite proximal end of the metal stem is provided with an integrally formed trunnion or male morse taper.
A metal ball, or femoral head, which includes a female morse taper, is adapted to be rigidly connected to the proximal end of the femoral stem as a result of the mating of the male and female morse tapers, such as for example, by means of an interference fit, or the like. Both the metal ball, or femoral head, as well as the femoral stem may be fabricated from the same suitable cobalt-chromium compositions, stainless steel, tantalum, or titanium. Furthermore, in accordance with more specific principles and teachings of the present invention, the metal ball, which effectively defines the basic structure of the femoral head, has an open-cell, highly porous metallic coating formed thereon, and then the highly porous coating is, in turn, coated with a suitable thermoplastic coating which may comprise, for example, highly cross-linked polyethylene. Well-known highly porous metallic coatings, such as, for example, those manufactured by DEPUY and sold under the trademark GRIPTION®, or those manufactured by SMITH & NEPHEW and sold under the trademark STIKTITE®, have micropores within the range of 100-1,000 microns. Accordingly, the thermoplastic coating is able to completely infiltrate the highly porous coating such that the thermoplastic and highly porous coatings can effectively interdigitate with each other so as to be integrally connected together. In other words, it can be readily appreciated that the resulting structure of the femoral head effectively forms a structural monobloc comprising the internal metal ball, the highly porous metallic coating coated upon the internal metal ball, and the outer coating of highly cross-linked polyethylene (HCLPE) coated upon the highly porous metallic coating. This ball or femoral head is then capable of being disposed within the metal liner disposed within the highly porous coated acetabular shell whereby a highly stable, but fully articulating prosthetic hip replacement assembly has been constructed. In accordance with a second embodiment of the present invention, the liner may effectively be eliminated whereby the structural monobloc comprising the internal metal ball, the highly porous metallic coating coated upon the internal metal ball, and the outer coating of highly cross-linked polyethylene (HCLPE) coated upon the highly porous metallic coating, is disposed within a highly polished internal surface of the metal cup forming the support structure of the highly porous coated acetabular shell.
Various other features and attendant advantages of the present invention will be more fully appreciated from the following detailed description when considered in connection with the accompanying drawings in which like reference characters designate like or corresponding parts throughout the several views, and wherein:
With reference now being made to
Furthermore, in accordance with more specific principles and teachings of the present invention, and again, as can best be appreciated from
With reference being made to
With reference lastly being made to
Obviously, many variations and modifications of the present invention are possible in light of the above teachings. For example, the femoral head, monobloc structure 510 can be fabricated so as to have various different head sizes having various different diametrical extents. In addition, and in a similar manner, the male and female morse tapers 508,512 may likewise be provided with various different sizes. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.
