Metal-reinforced polymer femoral component for orthopedic knee prosthesis and related method for fabricating the same

Abstract

An orthopedic knee prosthesis (10) comprises a femoral component having a metal base (84) from which a polymer joint layer is molded. A method for fabricating a metal-reinforced femoral component for an orthopedic knee prosthesis is also disclosed.

Description

Technical Field

[0001] The present disclosure generally relates to an implantable orthopedic knee prosthesis, and more particularly, to an implantable femoral component of an orthopedic knee prosthesis.

Background Art

[0002] During a patient's lifetime, it may become necessary to perform an arthroplasty on the patient, for example as a result of a disease or trauma. As a result, arthroplasty has become a well-known surgical procedure in which a diseased and / or damaged native joint is replaced with an artificial joint. For example, in the surgical procedure of total knee arthroplasty, the patient's native knee joint is partially or completely replaced with an artificial knee prosthesis. A typical knee prosthesis includes a tibial tray, a femoral component, and a polymeric insert or bearing positioned between the tibial tray and the femoral component. In such cases, the femoral component is fixed to the surgically prepared distal end of the patient's femur, and the tibial tray is fixed to the surgically prepared proximal end of the patient's tibia. The polymeric bearing is coupled to the tibial tray and thus provides a bearing surface for the femoral component to articulate during knee extension and flexion.

[0003] Conventional femoral components are embodied as monolithic metal components constructed of implant-grade biocompatible metals. Examples of such metals include cobalt, including cobalt alloys such as cobalt-chromium alloys, titanium, including titanium alloys such as Ti6Al4V alloy, and stainless steel, among others.

Summary of the Invention

Means for Solving the Problems

[0004] According to one aspect of the present disclosure, an orthopedic knee prosthesis comprises a femoral component. The femoral component comprises a metal base having a lower base surface curved in the sagittal plane. The lower base surface has a plurality of elongated ribs extending downward therefrom. The metal base also has an upper base surface having a posterior fixation surface extending generally upward / downward, a distal fixation surface extending generally forward / backward, a posterior chamfered fixation surface extending upward and backward in the direction from the distal fixation surface toward the posterior fixation surface, an anterior fixation surface extending generally upward / downward, and an anterior chamfered fixation surface extending upward and forward in the direction from the distal fixation surface toward the anterior fixation surface. The femoral component also comprises a polymer articulation layer molded into a plurality of elongated grooves defined by the plurality of ribs on the lower base surface of the metal base. The polymer articulation layer has an articulation surface that is curved in the sagittal plane and configured to articulate with the bearing surface of the tibial component.

[0005] In one embodiment, the porous metal coating is placed on the upper base surface of the metal base.

[0006] The porous metal coating may be placed over the entire rear fixing surface, distal fixing surface, rear chamfered fixing surface, front fixing surface, and front chamfered fixing surface of the upper base surface of the metal base.

[0007] In one embodiment, the metal base comprises several lugs extending upward from a distal fixed surface, and the porous metal coating is disposed on the lugs.

[0008] The lower end of each of the multiple ribs may have an undercut formed therein. The lower ends of the multiple ribs defining the undercut may have a rounded surface.

[0009] In one embodiment, the ribs extend in the sagittal plane. In another embodiment, the ribs extend in the coronal plane.

[0010] In one embodiment, multiple ribs are completely embedded within a polymer joint layer.

[0011] In one embodiment, some of the ribs are hollow.

[0012] The polymer articular layer of the femoral component may be constructed from polyaryletherketone (PAEK). In other embodiments, the polymer articular layer of the femoral component is constructed from other biocompatible polymers, copolymers, and / or polymer blends.

[0013] In another embodiment, an orthopedic knee prosthesis system comprises a tibial component configured to be implanted in the proximal end of the patient's tibia and a femoral component configured to be implanted in the distal end of the patient's femur. The tibial component includes a concave bearing surface. The femoral component comprises a metal base having a lower base surface curved in the sagittal plane. Multiple elongated ribs extend downward from the lower base surface. The metal base also comprises an upper base surface having multiple bone fixation surfaces. Multiple lugs extend upward from one of the multiple bone fixation surfaces. The femoral component also comprises a porous metal coating disposed on the upper base surface and lugs of the metal base. A polymer articular layer is molded into the lower base surface of the metal base and into multiple elongated grooves defined by the multiple ribs. The polymer articular layer has an articular surface that is curved in the sagittal plane and configured to articulate with the bearing surface of the tibial component.

[0014] In one embodiment, the upper base surface comprises a rear fixing surface extending generally upward / downward, a distal fixing surface extending generally forward / rearward, a rear chamfered fixing surface extending upward and rearward in the direction from the distal fixing surface toward the rear fixing surface, a front fixing surface extending generally upward / downward, and a front chamfered fixing surface extending upward and forward in the direction from the distal fixing surface toward the front fixing surface.

[0015] The porous metal coating may be placed over the entire rear fixing surface, distal fixing surface, rear chamfered fixing surface, front fixing surface, and front chamfered fixing surface of the upper base surface of the metal base.

[0016] The lower end of each of the multiple ribs may have an undercut formed therein. The lower ends of the multiple ribs defining the undercut may have a rounded surface.

[0017] In one embodiment, the ribs extend in the sagittal plane. In another embodiment, the ribs extend in the coronal plane.

[0018] In one embodiment, multiple ribs are completely embedded within a polymer joint layer.

[0019] In one embodiment, some of the ribs are hollow.

[0020] The polymer articular layer of the femoral component may be constructed from polyaryletherketone (PAEK). In other embodiments, the polymer articular layer of the femoral component is constructed from other biocompatible polymers, copolymers, and / or polymer blends.

[0021] In another embodiment, a method for fabricating a femoral component of an orthopedic knee prosthesis includes arranging a porous metal coating on a metal base. The metal base has an upper base surface comprising a plurality of bone fixation surfaces and a plurality of lugs. A polymer articular layer is molded on the lower base surface of the metal base, which is curved in the sagittal plane, and a plurality of elongated ribs extending downward from the lower base surface are embedded in the polymer articular layer, and the outer surface of the polymer articular layer is curved in the sagittal plane and forms an articular surface configured to articulate with the bearing surface of the tibial component.

[0022] Porous metal coatings can be placed on the upper base surface and several lugs of a metal base by 3D printing the porous metal coating and metal base as a monolithic metal part.

[0023] In one embodiment, the lower end of each of the plurality of ribs has an undercut formed therein, and the polymer articulating layer is formed on the lower base surface of the metal base such that the polymer articulating layer is molded into the undercut of each of the plurality of ribs.

Brief Description of the Drawings

[0024] For a detailed description, specifically, refer to the following drawings. [Figure 1] Fig. 10 is an exploded perspective view of an orthopedic knee prosthesis showing a metal-reinforced polymer femoral component, a tibial bearing, and a tibial tray. [Figure 2] Fig. 13 is a cross-sectional view of the metal-reinforced polymer femoral component and the tibial bearing of Fig. 1, taken in the direction of the arrow along line 2-2 of Fig. 1. [Figure 3] Fig. 16 is a perspective view of the metal-reinforced polymer femoral component of the orthopedic knee prosthesis of Fig. 1. [Figure 4] Fig. 19 is a perspective view of the metal base of the metal-reinforced polymer femoral component of Fig. 3. [Figure 5] Fig. 22 is a perspective view of the metal base of the metal-reinforced polymer femoral component of Fig. 3. [Figure 6] Fig. 25 is a lower elevation view of the elongated channel of the metal base of Figs. 4 and 5. [Figure 7] Fig. 28 is an enlarged cross-sectional view taken in the direction of the arrow along line 7-7 of Fig. 3. Note that in Fig. 7, the porous metal coating is not shown in cross-section for clarity of explanation.

Modes for Carrying Out the Invention

[0025] While the concepts of this disclosure are open to various modifications and alternative forms, specific exemplary embodiments are shown in the drawings and described in detail herein. However, it should be understood that this disclosure is not intended to limit the concepts to any particular form disclosed, but rather to encompass all modifications, equivalents, and alternatives that fall within the spirit and scope of the invention as defined by the attached "Claims."

[0026] Terms such as anterior, posterior, medial, lateral, superior, and inferior, which represent anatomical references, may be used throughout this specification in reference to orthopedic implants or prostheses and surgical instruments described herein, as well as to the natural anatomical structures of patients. Such terms have well-understood meanings in both the study of anatomy and the field of orthopedic surgery. The use of such anatomical reference terms in the descriptions and claims is intended to be consistent with their well-understood meanings unless otherwise specified.

[0027] Referring to Figures 1 and 2, an orthopedic knee prosthesis 10 is shown comprising a metal-reinforced polymer femoral component 12, a tibial bearing 14, and a tibial tray 16. The femoral component 12 is configured to articulate with the tibial bearing 14, which is configured to connect with the tibial tray 16. In the exemplary embodiment of Figure 1, the tibial bearing 14 is embodied as a rotatable or movable tibial bearing and is therefore rotatable relative to the tibial tray 16. However, in other embodiments, the tibial bearing 14 may be embodied as a fixed tibial bearing (not shown) that is restricted from rotation relative to the tibial tray 16.

[0028] The tibial tray 16 is configured to be fixed to the surgically prepared proximal end of the patient's tibia (not shown). The tibial tray 16 comprises a platform 18 having an upper surface 20 and an opposite lower surface 22. The tibial tray 16 also comprises a stem 24 extending downward from the bottom surface 22 of the platform 18. A hole 26 is defined in the upper surface 20 of the platform 18 and extends downward into the stem 24. The hole 26 is configured to receive a complementary stem 36 of the tibial bearing 14, as will be further detailed below.

[0029] The lower surface 22 of the platform 18 and the stem 24 define the bone engagement surface 28 of the tibial tray 16. As shown in Figure 1, the bone engagement surface 28 has a porous metal coating 32 placed thereon. It should be understood that the porous metal coating 32 may be a separately applied coating such as Porocoat®, Gription®, or Affixium® porous coatings, which are commercially available from DePuy Synthes in Warsaw, Indiana. Alternatively, the porous metal coating 32 may be placed on the metal body 34 of the tibial tray 16 by being additively manufactured at the same time as the metal body 34 of the tray to create a common monolithic component of the two metal structures.

[0030] As described above, the tibial bearing 14 is configured to be connected to the tibial tray 16. The tibial bearing 14 comprises a platform 30 having an upper bearing surface and a bottom bearing surface. In exemplary embodiments where the tibial bearing 14 is embodied as a rotatable or movable tibial bearing, the bearing 14 comprises a stem 36 extending downward from the bottom surface of the platform 30. When the tibial bearing 14 is connected to the tibial tray 16, the stem 36 is received in a hole 26 of the tibial tray 16. During use, the tibial bearing 14 is configured to rotate relative to the tibial tray 16 about an axis defined by the stem 36. In embodiments where the tibial bearing 14 is embodied as a fixed tibial bearing, the bearing 14 may or may not have a stem 36 and / or may have other devices or features for fixing the tibial bearing 14 to the tibial tray 16 in a non-rotatable configuration. The upper bearing surface of the tibial bearing 14 comprises an inner bearing surface 42 and an outer bearing surface 44. The inner bearing surface 42 and the outer bearing surface 44 are configured to receive, or otherwise contact, the corresponding medial condyles 52 and lateral condyles 54 of the femoral component 12. Thus, each of the bearing surfaces 42 and 44 has a concave contour.

[0031] Referring to Figure 2, the femoral component 12 is configured to connect to a surgically prepared surface at the distal end of the patient's femur (not shown). The femoral component 12 shown in Figures 1 and 2 is a posterior cruciate ligament-preserving knee prosthesis, and the tibial bearing 14 is embodied as a posterior cruciate ligament-preserving tibial bearing 14. However, in other embodiments, the orthopedic knee prosthesis 10 may be embodied as a posterior cruciate ligament-sacrificial knee prosthesis (not shown).

[0032] As described above, the femoral component 12 comprises a pair of medial and lateral condyles 52 and 54. The condyles 52 and 54 are spaced apart to define an intracondylar notch 56 between them. In use, the condyles 52 and 54 replace the natural condyles of the patient's femur. Each condyle 52 and 54 of the femoral component 12 is convex in the sagittal plane and has a lateral articular surface 50 configured to articulate with the respective bearing surfaces 42 and 44 of the tibial bearing 14.

[0033] On the opposite side of the articular surface 50, the femoral component 12 has a bone engagement surface 62. The bone engagement surface 62 contacts the patient's surgically prepared distal femur. The bone engagement surface 62 has multiple surfaces that engage with a planar surface surgically cut into the patient's distal femur. For example, as shown in Figure 2, a pair of posterior fixation surfaces 64 are opposite the posterior surfaces of the condyles 52, 54, with one of the posterior fixation surfaces 64 being the medial fixation surface and the other being the lateral fixation surface. As can be seen in Figures 1 and 2, the posterior fixation surfaces 64 extend generally in the superior / inferior direction. A pair of distal fixation surfaces 66 (one positioned medially and the other laterally) are opposite the distal surfaces of the condyles 52, 54 and extend generally in the anterior / posterior direction. A pair of posterior chamfered fixation surfaces 68 (one positioned medially and the other laterally) are opposite the posterior chamfered surfaces of the condyles 52, 54. The medial and lateral posterior chamfered fixing surfaces 68 extend upward and backward from their respective medial and lateral distal fixing surfaces 66 in the direction toward their respective posterior fixing surfaces 64. The medial and lateral anterior chamfered fixing surfaces 70 are located opposite the anterior chamfered surfaces of the condyles 52 and 54, respectively, and extend upward and forward in the direction toward the anterior fixing surface 72 away from their respective distal fixing surfaces 66. The anterior fixing surface 72 is opposite the anterior condylar surface and extends generally upward / downward, like the posterior fixing surface 64.

[0034] The bone engagement surface 62 of the femoral component 12 may also have outer surfaces of a pair of lugs 74 extending upward from the distal fixation surface 66. The lugs 74 are configured to be received into holes formed in the patient's surgically prepared distal femur during the placement of the femoral component 12.

[0035] The femoral component 12 described herein is embodied as a metal-reinforced polymer component. Thus, the femoral component 12 comprises a polymer articular layer 82 molded on a metal base 84 to produce a one-piece (i.e., non-modular) final product. The articular surface 50 of the femoral component 12 is formed in the polymer articular layer 82 of the femoral component 12 and thus defines a polymer articular surface configured to articulate on the bearing surfaces 42, 44 of the tibial bearing 14.

[0036] The polymer joint layer 82 of the femoral component 12 is embodied as a monolithic polymer body constructed of a material that allows smooth joint movement between the femoral component 12 and the tibial bearing 14 (generally constructed of a biocompatible polymer such as polyethylene containing ultra-high molecular weight polyethylene (UHMWPE)). A polymer or a blend of polymers is preferably used to construct the polymer joint layer 82. As used herein, the term “polymer” is intended to mean any polymer material that can be implanted in a patient. Specific examples of polymers that can be used to construct the femoral component 12 are the polyaryletherketone (PAEK) family, the polysulfone family, the polyimide family, and the polyacetal family. The term “polyaryletherketone” as defined herein includes polyetheretherketone (PEEK), polyetherketone, and polyetherketone, or any other type of polyaryletherketone used to construct artificial implants, including PEEK blends such as PEEK-polyetherimide and PEEK-polyphenylsulfone blends.

[0037] Where used herein, the term “layer” is not intended to be limited to a “thickness” of a material located in close proximity to another “thickness” of the material of similar dimensions, but rather to include a number of structures, compositions, and constructs of the material. For example, the term “layer” may include a part, region, or other structure of a material located in close proximity to another part, region, or structure of a different material.

[0038] Referring here to Figures 4-7, the metal base 84 is shown in more detail. As best shown in Figure 4 (and the cross-sectional view in Figure 2), the metal base 84 of the femoral component 12 comprises an upper base surface 86 containing the bone engagement surface 62 of the component, and an opposite lower base surface 88 into which the polymer articular layer 82 is molded. As seen in Figures 2-4, the posterior fixation surface 64, distal fixation surface 66, posterior chamfered fixation surface 68, anterior chamfered fixation surface 70, and anterior fixation surface 72 are formed within the upper base surface 86.

[0039] As seen in Figures 2 and 4, the lower base surface 88 is curved in the sagittal plane and extends generally parallel to the articular surface 50 of the femoral component. Multiple elongated ribs 90 extend downward from the lower base surface 88. Similar to the lower base surface 88, the elongated ribs 90 extend in the sagittal plane. The lower end 92 of each of the multiple ribs 90 has an undercut 94 formed therein. Specifically, the lower end 92 of each rib 90 is wider than the opposite end of the rib 90 (i.e., the end of the rib 90 fixed to the lower base surface 88). As seen in Figure 7, the ribs 90 extend from their lower ends 92 along a convex surface 96 that transitions to a concave surface 98 before transitioning to the lower base surface 88, thereby creating the undercut 94. While the undercut 94 is shown as a blend radius undercut 40 (i.e., the surface defining the undercut is rounded), it should be understood that other configurations are also intended, including more square undercuts in the design (e.g., rib 90 defining an orthogonal transition instead of a rounded transition).

[0040] As shown in Figure 7, the surface of the rib 90 defining the undercut 94 creates a composite surface that faces away from the lower base surface 88 of the metal base 84 into which the polymer joint layer 82 is formed. In this way, the undercut 94 resists the polymer joint layer 82 from being peeled away from the metal base 84.

[0041] In this specification, the rib 90 is described as extending in the sagittal plane, but it should be understood that other configurations of the rib 90 may be used to suit the requirements of a given design of the femoral component 12. For example, the rib 90 may be positioned to extend in the coronal plane. As a further example, the rib 90 may be positioned to extend in both the sagittal and coronal planes.

[0042] Furthermore, it should be understood that the number and shape of the ribs 90 (e.g., length, width, cross-sectional shape, etc.) may be modified to suit the needs of a given design of the femoral component 12 and / or to impart desired properties to a given design of the femoral component 12. For example, the stiffness of the metal base 84 can be controlled as a function of the number of ribs 90 and the cross-sectional shape of the ribs 90. Moreover, the ribs 90 may be constructed as hollow structures (e.g., by using 3D printing). This allows for the creation of outer rib shapes useful for forming the polymer joint layer 82 into the metal base 84, while also allowing the overall stiffness of the femoral component 12 to be controlled by changing the wall thickness of the hollow ribs. In such embodiments, the wall thickness may be uniform throughout the cross-section of the rib 90, or it may be thicker in some areas (e.g., the lower end 92 of the rib 90) and thinner in others, based on the desired structural stiffness in a given design of the femoral component 12.

[0043] The femoral component 12 is embodied as a cementless component; that is, it is designed to be attached to the surgically prepared distal end of the patient's femur without the use of bone cement. Therefore, the bone engagement surface 62 of the femoral component has a porous metal coating 32 placed thereon. Similar to the tibial tray 16, the porous metal coating 32 placed on the femoral component 12 may be a separately applied coating (e.g., Porocoat®, Gription®, or Affixium® porous coating). However, in the exemplary embodiments described herein, the porous metal coating 32 is additively manufactured simultaneously with the metal base 84, thereby being placed on the metal base 84 to create a common monolithic component of the two metal structures. For example, the Affixium® porous coating may be additively manufactured simultaneously with the metal base to create a common monolithic component.

[0044] For example, the porous metal coating 32 may be made of a porous material 80 as described in U.S. Patent Application No. 16 / 365,557, filed on March 26, 2019, and assigned to the same assignee as the present disclosure, the disclosure of which is incorporated herein by reference as if it were described in whole. Additive manufacturing processes may include, as an example, powder bed fusion printing such as melting and sintering, cold spray 3D printing, wire feed 3D printing, melt deposit 3D printing, extrusion 3D printing, liquid metal 3D printing, stereolithography 3D printing, binder jet 3D printing, material jet 3D printing, and the like.

[0045] In one example, referring to Figure 7, the porous material 80 of the porous metal coating 32 can be defined by a porous three-dimensional structure that can include a plurality of connected unit cells. Each unit cell can define a unit cell structure that includes a plurality of grid pillars defining an outer geometric structure, and a plurality of internal pillars defining a plurality of internal geometric structures arranged within the outer geometric structure. In one example, the outer geometric structure may be a rhombic dodecahedron, and the internal geometric structure may be a rhombic trapezoid. It should be understood that such geometric structures can be modified to suit the requirements of a given design. Furthermore, it should be understood that the unit cells constituting the porous metal coating 32 may also have any suitable alternative shapes to suit the requirements of a given design.

[0046] The porous material 80 is formed from metal powder. Exemplarily, the metal powder may include, but is not limited to, titanium, titanium alloys, stainless steel, cobalt-chromium alloys, tantalum, or niobium powder. The porous metal coating 32 has suitable porosity for promoting internal bone growth into the femoral component 12 when the upper base surface 86 and lug 74 of the metal base 84 are embedded within the surgically prepared posterior surface of the patient's patella.

[0047] In the exemplary embodiments described herein, the porous metal coating 32 is additively fabricated directly onto the upper base surface 86 and lugs 74 of the metal base 84. In such embodiments, the two structures, namely the metal base 84 and the porous metal coating 32, can be fabricated simultaneously during a typical additive manufacturing process. For example, the two structures may be fabricated simultaneously in a single 3D printing operation that yields a common monolithic metal component containing both structures. Alternatively, the porous metal coating 32 can be fabricated as a separate component fixed to the metal base 84.

[0048] The polymer joint layer 82 can be assembled to the metal base 84 by using several different techniques. One exemplary method for doing this is by using compression molding techniques. For example, the metal base 84 and the material from which the polymer joint layer 82 is made (e.g., PEEK) can be placed relative to each other in a mold. The material from which the polymer joint layer 82 is made (e.g., PEEK) is then melted and the components are compression molded relative to each other under process parameters that mechanically fix them to the metal base 84 by a compression molding process. As described above, the molten polymer joint layer 82 interlocks with the ribs 90 of the metal base 84 when molded to the metal base 84 (i.e., the molten polymer joint layer 82 is injected into the grooves 102 defined by the ribs 90). It should also be understood that the mold may be configured not only to mold the components relative to each other but also to form the articular surface 50 of the femoral component 12 in the polymer joint layer 82. Another exemplary and equally effective method for assembling the polymer joint layer 82 to the metal base 84 is by using injection molding.

[0049] Starting materials for use in the molding process (e.g., polymers such as PEEK) may be provided in several different forms. For example, each of the starting materials may be provided as a preform. In this specification, the term “preform” means an article in which polymer resin particles are consolidated into rods, sheets, blocks, slabs, etc., by ram extrusion or compression molding, etc. The term “preform” also includes preform “packs” that may be prepared by intermediate machining of commercially available preforms. Polymer preforms may be provided in several different pre-treated or pre-adjusted variations. For example, crosslinked or non-crosslinked (e.g., irradiated or unirradiated) preforms may be utilized. Such preforms may be treated to remove free radicals present therein (e.g., remelting or quenching) or to stabilize them (e.g., by adding vitamin E as an antioxidant). Alternatively, the preforms may not be treated in such a manner.

[0050] Starting materials (e.g., polymers, copolymers, and / or blended polymers) may be provided as powders or pellets. In this specification, the terms “powder” and “pellets” refer to resin particles. As with respect to preforms, powders and / or pellets may be provided in a number of different pre-treated or pre-prepared variations. For example, crosslinked or non-crosslinked (e.g., irradiated or unirradiated) powders and / or pellets may be utilized. Furthermore, in the case of blended polymers, powders and / or pellets may be provided as pre-blended resin particles, or they may be blended in situ in a hopper associated with a molding machine to produce a desired blend composition for use in the molding process.

[0051] As described herein, the metal-reinforced femoral component 12 has certain enhanced properties. For example, the use of a ribbed metal base 84 increases the overall rigidity of the component and creates a uniform wall thickness for precise injection molding of the polymer joint layer 82.

[0052] In some designs of the femoral component 12, spray coating is used as an alternative to the use of a metal base 84. For example, a titanium plasma spray (TPS) coating can be applied to a pre-formed polymer femoral component to provide a metal layer on the back side of the component. Another alternative approach is the use of a two-shot molding process. In such a case, the polymer articular layer 82 is formed in a first shot, and then a porous coating is applied to the back side of the articular layer 82 via a second shot filled with porogen.

[0053] While the drawings and the above description have illustrated and illustrated the present disclosure in detail, such illustrations and descriptions are, by their nature, illustrative and not limiting, and merely illustrate exemplary embodiments. It is understood that all changes and modifications included in the spirit of the present disclosure should be protected.

[0054] This disclosure offers several advantages based on the various features of the methods, apparatus, and systems described herein. It should be noted that alternative embodiments of the methods, apparatus, and systems of this disclosure do not include all of the features described, but still benefit from at least some of the advantages of such features. Those skilled in the art can easily independently implement methods, apparatus, and systems that incorporate one or more of the features of the present invention, encompassing the spirit and scope of this disclosure as defined in the appended "Claims."

[0055] [Implementation Method] (1) An orthopedic knee prosthesis, A femoral component, A metal base comprising: (i) a lower base surface curved in the sagittal plane and having a plurality of elongated ribs extending downward therefrom; and (ii) an upper base surface having (a) a rear fixing surface extending generally upward / downward, (b) a distal fixing surface extending generally forward / rearward, (c) a rear chamfered fixing surface extending upward and rearward in the direction from the distal fixing surface toward the rear fixing surface, (d) a front fixing surface extending generally upward / downward, and (e) a front chamfered fixing surface extending upward and forward in the direction from the distal fixing surface toward the front fixing surface; An orthopedic knee prosthesis comprising a femoral component, the polymer joint layer having an articulating surface that is curved in the sagittal plane and configured to articulate with the bearing surface of the tibial component, the polymer joint layer being molded in a plurality of elongated grooves defined by the plurality of ribs on the lower base surface of the metal base. (2) The orthopedic knee prosthesis according to Embodiment 1, wherein a porous metal coating is disposed on the upper base surface of the metal base. (3) The orthopedic knee prosthesis according to Embodiment 1, wherein a porous metal coating is disposed over the entire posterior fixing surface, distal fixing surface, posterior chamfered fixing surface, anterior fixing surface, and anterior chamfered fixing surface of the upper base surface of the metal base. (4) The metal base comprises several lugs extending upward from the distal fixing surface, An orthopedic knee prosthesis according to Embodiment 1, wherein a porous metal coating is disposed on the upper base surface and the lug of the metal base. (5) The orthopedic knee prosthesis according to Embodiment 1, wherein the lower end of each of the plurality of ribs has an undercut formed therein.

[0056] (6) The orthopedic knee prosthesis according to Embodiment 5, wherein the lower ends of the plurality of ribs defining the undercut have rounded surfaces. (7) The orthopedic knee prosthesis according to Embodiment 1, wherein the plurality of ribs extend in the sagittal plane. (8) The orthopedic knee prosthesis according to Embodiment 1, wherein the plurality of ribs extend to the coronal surface. (9) The orthopedic knee prosthesis according to Embodiment 1, wherein the plurality of ribs are completely embedded within the polymer joint layer. (10) The orthopedic knee prosthesis according to Embodiment 1, wherein some of the plurality of ribs are hollow.

[0057] (11) The orthopedic knee prosthesis according to Embodiment 1, wherein the polymer joint layer of the femoral component comprises polyaryl ether ketone (PAEK). (12) An orthopedic knee prosthesis system, A tibial component configured to be embedded in the proximal end of a patient's tibia, comprising a tibial component having a concave bearing surface, A femoral component configured to be embedded in the distal end of the femur of a patient, wherein the femoral component is A metal base comprising: (i) a lower base surface curved in the sagittal plane and having a plurality of elongated ribs extending downward therefrom; and (ii) an upper base surface having (a) several bone fixation surfaces and (b) several lugs extending upward from one of the bone fixation surfaces; A porous metal coating disposed on the upper base surface and the lug of the metal base, An orthopedic knee prosthesis system comprising: a polymer joint layer molded on the lower base surface of the metal base and in a plurality of elongated grooves defined by the plurality of ribs, the polymer joint layer having an articular surface that is curved in the sagittal plane and configured to articulate with the bearing surface of the tibial component; and a femoral component. (13) The several bone fixing surfaces of the upper base surface, A rear fixed surface that generally extends in the upward / downward direction, A distal fixation surface that generally extends in the anterior / posterior direction, A rear chamfered fixing surface extending upward and rearward in the direction toward the rear fixing surface from the distal fixing surface, A forward fixed surface that generally extends in the upward / downward direction, An orthopedic knee prosthesis system according to embodiment 12, comprising an anterior chamfered fixing surface extending upward and forward in the direction toward the anterior fixing surface from the distal fixing surface. (14) The orthopedic knee prosthesis system according to Embodiment 13, wherein the porous metal coating is disposed over the entire posterior fixing surface, distal fixing surface, posterior chamfered fixing surface, anterior fixing surface, and anterior chamfered fixing surface of the upper base surface of the metal base. (15) The orthopedic knee prosthesis system according to embodiment 12, wherein the lower end of each of the plurality of ribs has an undercut formed therein.

[0058] (16) The orthopedic knee prosthesis system according to embodiment 15, wherein the lower ends of the plurality of ribs defining the undercut have rounded surfaces. (17) The orthopedic knee prosthesis system according to embodiment 12, wherein the plurality of ribs extend in the sagittal plane. (18) The orthopedic knee prosthesis system according to embodiment 12, wherein the plurality of ribs extend to the coronal surface. (19) The orthopedic knee prosthesis system according to embodiment 12, wherein the plurality of ribs are completely embedded within the polymer joint layer. (20) The orthopedic knee prosthesis according to embodiment 12, wherein some of the plurality of ribs are hollow.

[0059] (21) The orthopedic knee prosthesis system according to Embodiment 12, wherein the polymer joint layer of the femoral component comprises polyaryl ether ketone (PAEK). (22) A method for fabricating a femoral component of an orthopedic knee prosthesis, (i) an upper base surface including several bone fixation surfaces, and (ii) a porous metal coating placed on a metal base having several lugs, A method comprising molding a polymer articular layer onto a lower base surface of a metal base that is curved in the sagittal plane, wherein (i) a plurality of elongated ribs extending downward from the lower base surface are embedded in the polymer articular layer, and (ii) the outer surface of the polymer articular layer forms an articular surface that is curved in the sagittal plane and configured to articulate with the bearing surface of a tibial component. (23) The method according to embodiment 22, wherein arranging the porous metal coating on the upper base surface and several lugs of the metal base is 3D printed as a monolithic metal part the porous metal coating and the metal base. (24) Each of the plurality of ribs has an undercut formed therein, The method according to Embodiment 22, wherein forming the polymer joint layer on the lower base surface of the metal base is performed such that the polymer joint layer is formed into the undercuts of each of the plurality of ribs.

Claims

1. It is an orthopedic knee prosthesis, A femoral component, A metal base comprising: (i) a lower base surface curved in the sagittal plane and having a plurality of elongated ribs extending downward therefrom; and (ii) an upper base surface having (a) a rear fixing surface extending generally upward / downward, (b) a distal fixing surface extending generally forward / rearward, (c) a rear chamfered fixing surface extending upward and rearward in the direction from the distal fixing surface toward the rear fixing surface, (d) a front fixing surface extending generally upward / downward, and (e) a front chamfered fixing surface extending upward and forward in the direction from the distal fixing surface toward the front fixing surface; An orthopedic knee prosthesis comprising a femoral component, the polymer joint layer having an articulating surface that is curved in the sagittal plane and configured to articulate with the bearing surface of the tibial component, the polymer joint layer being molded in a plurality of elongated grooves defined by the plurality of ribs on the lower base surface of the metal base.

2. The orthopedic knee prosthesis according to claim 1, wherein a porous metal coating is disposed on the upper base surface of the metal base.

3. The orthopedic knee prosthesis according to claim 1, wherein a porous metal coating is disposed over the entire posterior fixing surface, distal fixing surface, posterior chamfered fixing surface, anterior fixing surface, and anterior chamfered fixing surface of the upper base surface of the metal base.

4. The metal base comprises several lugs extending upward from the distal fixing surface, The orthopedic knee prosthesis according to claim 1, wherein a porous metal coating is disposed on the upper base surface and the lug of the metal base.

5. The orthopedic knee prosthesis according to claim 1, wherein the lower end of each of the plurality of ribs has an undercut formed therein.

6. The orthopedic knee prosthesis according to claim 5, wherein the lower ends of the plurality of ribs defining the undercut have rounded surfaces.

7. The orthopedic knee prosthesis according to claim 1, wherein the plurality of ribs extend in the sagittal plane.

8. The orthopedic knee prosthesis according to claim 1, wherein the plurality of ribs extend to the coronal surface.

9. The orthopedic knee prosthesis according to claim 1, wherein the plurality of ribs are completely embedded within the polymer joint layer.

10. The orthopedic knee prosthesis according to claim 1, wherein some of the plurality of ribs are hollow.

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