Metal-backed patella component of an orthopedic knee joint prosthesis and associated method of manufacturing same

Abstract

The orthopedic implant includes a patella component (10) having a metal base (14) with a molded polymer bearing (12). The metal base includes a posterior base surface (16) with a pocket (30) and an anterior base surface (22) with a number of pegs (24) configured to be implanted into the patient's natural patella, the anterior base surface and the pegs being coated with porous metal. A method of manufacturing the patella component is also disclosed.

Description

[Technical field]

[0001] The present disclosure relates generally to implantable orthopaedic knee prostheses, and more particularly to implantable patellar components of orthopaedic knee prostheses. [Background technology]

[0002] During a patient's lifetime, for example as a result of disease or trauma, it may become necessary for the patient to undergo joint replacement surgery. Joint replacement surgery may involve the use of a prosthesis that is implanted into one or more bones of the patient. In the case of patella replacement surgery, an orthopedic prosthesis is implanted into the patient's patella. Specifically, the artificial patella component is secured to the patient's natural patella such that its posterior surface articulates with the femoral component during knee extension and flexion.

[0003] A conventional dome-type patella component is embodied as a dome-shaped polymer bearing. Other types of patella components include conformal or anatomical bearings designed to conform to the bearing surface of the femur. The dome-type patella component allows for greater movement between the patella component and the femoral component of the knee prosthesis, but the anatomical patella component is more constrained than the femoral component. Either type of patella component has clinical advantages to suit the needs of a given surgical procedure. Summary of the Invention [Means for solving the problem]

[0004] According to one aspect of the present disclosure, an orthopaedic implant includes a patella component. The patella component has a solid metal base including a posterior base surface with a number of pockets formed therein. Each pocket has an undercut formed therein. The solid metal base also has an anterior base surface with a number of pegs extending outwardly therefrom. A porous metal coating is disposed on the anterior base surface and the pegs of the solid metal base. A polymer bearing is molded onto the posterior base surface of the solid metal base. The polymer bearing has a posterior bearing surface configured to articulate with a pair of femoral condyles of the femoral component.

[0005] In one embodiment, the polymer bearing is molded into a pocket in a solid metal base.

[0006] Illustratively, the rear end of each pocket is defined by an opening formed in the rear base surface, and the front end of each pocket is defined by a base wall spaced forwardly from the opening. The interior and exterior of the pocket are defined by a pair of side walls extending from the opening to the base wall. The side walls have an undercut formed therein.

[0007] In one embodiment, the surface of the sidewall that defines the undercut has a rounded surface.

[0008] Illustratively, some adjacent pockets in the solid metal base are open to one another.

[0009] In one embodiment, the solid metal base further includes a peripheral sidewall extending between the rear base surface and the front base surface, the peripheral sidewall having a number of pockets formed therein, each pocket formed in the peripheral sidewall having a porous metal coating disposed therein.

[0010] Illustratively, the patella component may be embodied as a dome-shaped patella component or an anatomical patella component.

[0011] According to another aspect, an orthopaedic implant includes a patella component. The patella component includes a solid metal base having a posterior base surface with a number of pockets formed therein and an anterior base surface having a number of pegs extending outwardly. A posterior end of each pocket is defined by an opening formed in the posterior base surface and an anterior end of each pocket is defined by a base wall spaced anteriorly from the opening. Medial and lateral sides of the pockets are defined by a pair of side walls extending from the opening to the base wall. A number of adjacent pockets are open to one another. A porous metal coating is disposed on the anterior base surface and the pegs of the solid metal base. A polymer bearing is molded onto the posterior base surface of the solid metal base. The polymer bearing has a posterior bearing surface configured to articulate with a pair of femoral condyles of the femoral component.

[0012] In one embodiment, the polymer bearing is molded into a pocket in a solid metal base.

[0013] In one embodiment, the surface of the sidewall that defines the undercut has a rounded surface.

[0014] In one embodiment, the solid metal base further includes a peripheral sidewall extending between the rear base surface and the front base surface, the peripheral sidewall having a number of pockets formed therein, each pocket formed in the peripheral sidewall having a porous metal coating disposed therein.

[0015] Illustratively, the patella component may be embodied as a dome-shaped patella component or an anatomical patella component.

[0016] According to yet another aspect of the present disclosure, a method of manufacturing a patella component includes disposing a porous metal coating on an anterior surface of a solid metal base and on a number of pegs. A polymer bearing is molded onto a posterior surface of the solid metal base such that a portion of the anterior surface of the polymer bearing is disposed within a number of pockets formed in the posterior surface of the solid metal base. The posterior surface of the polymer bearing forms a patella bearing surface configured to articulate with a pair of femoral condyles of a femoral component.

[0017] Illustratively, the porous metal coating and the solid metal base are 3D printed as a unitary metal part.

[0018] In one embodiment, some sidewalls that define a pocket in the solid metal base have undercuts formed therein, and the polymer bearing is molded onto the rear surface of the solid metal base such that a portion of the front surface of the polymer bearing is molded into the sidewalls that define the undercuts of the pocket.

[0019] The polymer bearing may be molded to include either a domed patella bearing surface or an anatomic patella bearing surface, both of which are configured to articulate with a pair of femoral condyles of the femoral component. [Brief description of the drawings]

[0020] The detailed description makes specific reference to the following drawings: [Figure 1] FIG. 1 is a perspective view of a metal-backed dome-shaped patella component of an orthopedic knee prosthesis. [Diagram 2] FIG. 2 is a top elevational view of the metal-backed dome-shaped patella component of FIG. 1. [Diagram 3] FIG. 2 is a front elevational view of the metal-backed dome-shaped patella component of FIG. 1. [Figure 4] 4 is a cross-sectional view taken along line 4-4 of FIG. 3, looking in the direction of the arrows; note that for clarity of illustration, the porous metal coating is not shown in the cross-sectional view of FIG. [Diagram 5]FIG. 2 is a perspective view of the solid metal base of the metal-backed dome-shaped patella component of FIG. [Figure 6] FIG. 6 is a rear elevational view of the solid metal base of FIG. [Figure 7] FIG. 6 is a top elevational view of the solid metal base of FIG. [Figure 8] FIG. 7 is a view similar to FIG. 6, but showing the solid metal base with a thin layer of the rear surface removed. [Figure 9] 9 is a cross-sectional view taken along line 9-9 of FIG. 6, looking in the direction of the arrows; note that for clarity of illustration, the porous metal coating is not shown in the cross-sectional view of FIG. [Figure 10] FIG. 10 is an enlarged cross-sectional view showing the pocket of the solid metal base in greater detail, as indicated by the circled area, taken from FIG. 9. [Figure 11] FIG. 2 is a view similar to FIG. 1, but showing a metal-backed anatomical patella component of an orthopedic knee prosthesis. [Figure 12] FIG. 12 is a front perspective view of the metal-backed anatomical patella component of FIG. [Figure 13] FIG. 7 is a view similar to FIG. 6, but showing the solid metal base of the metal-backed dome-shaped patella component of FIG. 1 with a porous metal coating disposed within the pocket. [Figure 14] FIG. 9 is a view similar to FIG. 8, but showing the solid metal base of the metal-backed dome-shaped patella component of FIG. 1 with a porous metal coating disposed within the pocket. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and are herein described in detail, It should be understood, however, that there is no intention to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

[0022] Terms denoting anatomical references, such as anterior, posterior, medial, lateral, superior, inferior, etc., may be used throughout this specification in connection with the orthopedic implants or prostheses and surgical instruments described herein, as well as in connection with the patient's natural anatomy. Such terms have meanings that are well understood in both the study of anatomy and in the field of orthopedic surgery. Use of such anatomical reference terms in the written specification and claims is intended to be consistent with their well understood meanings, unless otherwise indicated.

[0023] 1-4, there is shown a metal-backed domed patellar component 10 of an implantable prosthetic knee joint. As described in more detail below, the domed patellar component 10 includes a polymer bearing 12 molded onto a solid metal base 14 to form a one-piece (i.e., non-modular) end product. The polymer bearing 12 of the domed patellar component 10 includes a posterior bearing surface 16 configured to articulate with a pair of condyle surfaces of a femoral component (not shown) secured to a surgically-prepared end of a patient's distal femur (not shown). In particular, the posterior bearing surface 16 of the domed patellar component 10 includes a lateral articular surface 18 and a medial articular surface 20. The articular surfaces 18, 20 are configured to articulate with the lateral and medial condyle surfaces, respectively, of the femoral component (not shown). It should be understood that such femoral components are configured to mimic the configuration of the patient's natural femoral condyles, and therefore the lateral and medial condyle surfaces of the artificial femoral component are configured (e.g., curved) to mimic the condyles of the natural femur.

[0024] As can be seen in Figures 2-4, the solid metal base 14 of the dome-shaped patella component 10 includes a generally flat anterior surface 22 having a number of fixation members, such as pegs 24, extending outwardly therefrom. The pegs 24 are configured to be implanted into the surgically-prepared posterior surface of a patient's natural patella (not shown). In this manner, the posterior bearing surface 16 of the dome-shaped patella component 10 faces the femoral component, thereby allowing the posterior bearing surface 16 to articulate with the femoral condyle surface thereof during flexion and extension of the patient's knee.

[0025] The polymer bearing 12 of the dome-shaped patella component 10 is embodied as a one-piece polymer body constructed of a material that allows for smooth articulation between the patella component 10 and the femoral component (typically constructed of a biocompatible metal such as a cobalt-chromium alloy, although other materials such as ceramics may also be used). One such polymeric material is polyethylene, such as ultrahigh molecular weight polyethylene (UHMWPE).

[0026] 4-10, the solid metal base 14 is shown in greater detail. Opposite its front surface 22, the solid metal base 14 includes a rounded rear surface 26 onto which the polymer bearing 12 is molded. The rear surface 26 has a number of pockets 30 formed therein. As will be described below, the pockets 30 allow for interdigitation of the polymer when molding the polymer bearing 12 molded onto the solid metal base 14. As can be seen in FIG. 6, in the exemplary embodiment described herein, the pockets 30 are arranged on the rear surface 26 in a cross-hatch type pattern, although other patterns may be used. As can be seen in FIGS. 4, 9 and 10, the rear end of each pocket 30 is defined by an opening 32 formed in the rear surface 26, and the opposite front end of the pocket is defined by a base wall 34. The base wall 34 is spaced forward from the opening 32 toward the center of the body of the solid metal base 14. The interior and exterior of the pocket 30 are defined by a pair of side walls 36 that extend from the opening 32 to the base wall 34 .

[0027] As can be seen in Figures 4, 9 and 10, each pocket 30 has an undercut 40 formed therein. Specifically, the base wall 34 defining the front end of each pocket 30 is wider than the opening 32 defining the rear end of each pocket 30. The sidewall 36 extends away from the opening 32 along a convex surface 42 that transitions to a concave surface 44 and then to the base wall 34, thereby forming the undercut 40. Although the undercut 40 is shown as a blended radius undercut 40 (i.e., the surfaces defining the undercut are rounded), it should be understood that other configurations are also contemplated, including, for example, undercuts that are more squared off in design (e.g., the sidewall 36 defines an orthogonal transition instead of a rounded transition).

[0028] 4, the sidewall 36 defining the undercut 40 forms a surface facing away from the outer rear surface 26 of the solid metal base 14 onto which the polymer bearing 12 is molded. In this manner, the undercut 40 resists delamination of the polymer bearing 12 from the solid metal base 14.

[0029] As can be seen from FIG. 8, adjacent pockets 30 of the crosshatch pattern of a given row are open to one another. In particular, as can be seen from the situation in FIG. 8 where a thin outer layer of the rear face 26 of the solid metal base 14 has been removed, the base walls 34 of the pockets 30 of a given row extend across most of the width of the solid metal base 14. Side walls 36 close a given pocket 30 in the inward / outward direction, but there are no side walls disposed between the pockets 30 of a given row extending in the upward / downward direction. Thus, adjacent pockets 30 in such a row extending in the upward / downward direction are open to one another, thereby allowing polymeric material to be advanced between adjacent pockets 30 and thus under the sections 46 of the rear face 26 between the pockets 30. The undersides of the sections 46 form a surface facing away from the outer rear face 26 of the solid metal base 14 on which the polymeric bearing 12 is molded. In this way, the undersides of the sections 46 resist peeling of the polymeric bearing 12 from the solid metal base 14.

[0030] As can be seen in Figures 5 and 7, the outer peripheral sidewall 50 extends between the posterior surface 26 of the solid metal base 14 and its anterior surface 22. Because the domed patella component 10 is embodied as a medially offset domed patella component 10, the peripheral sidewall 50 is wider on the medial side of the solid metal base 14 than on the lateral side of the solid metal base 14. As can be seen in Figures 5-7, the upper, lower, and medial sides of the peripheral sidewall 50 have several wall pockets 52 formed therein. The wall pockets 52 extend inwardly from openings 54 formed in the peripheral sidewall 50 to the center of the solid metal base 14. Similar to the pockets 30 formed in the posterior surface 26 of the solid metal base 14, the wall pockets 52 allow for interdigitation of the polymer into the solid metal base 14 when molding the polymer bearing 12 molded onto the solid metal base 14.

[0031] As can be seen in Figures 2-5, the front surface 22 and the pegs 24 of the solid metal base 14 have a porous metal coating 60 disposed thereon. As can be seen in Figures 5 and 7, the porous metal coating 60 may also be disposed in the wall pockets 50 of the solid metal base 14. It should be understood that the porous metal coating 60 may be a separately applied coating, such as Porocat® porous coating, available from DePuy Synthes of Warsaw, Indiana. However, in the exemplary embodiment described herein, the porous metal coating 60 is disposed on the solid metal base 14 by being additively manufactured simultaneously with the solid metal base 14, forming a common, integral part of the two metal structures.

[0032] In one example, the porous metal coating 60 may be made of the porous material 62 described in U.S. Patent Application No. 16 / 365,557, filed March 26, 2019, and assigned to the same assignee as this disclosure, the disclosure of which is incorporated by reference as if set forth in its entirety herein. Additive manufacturing processes may include, by way of example, powder bed fusion printing, such as fusion and sintering, cold spray 3D printing, wire feed 3D printing, fused deposition 3D printing, extrusion 3D printing, liquid metal 3D printing, stereolithography 3D printing, binder jet 3D printing, material jet 3D printing, and the like.

[0033] In one example, referring to FIG. 4, the porous material 62 of the porous metal coating 60 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 64 that includes a plurality of lattice struts that define an exterior geometric structure and a plurality of interior struts that define a plurality of interior geometric structures disposed within the exterior geometric structure. In one example, the exterior geometric structure can be a rhombic dodecahedron and the interior geometric structure can be a rhombic triangular twisted bipyramid. It is understood that such geometric structures can be varied to suit the needs of a given design. Furthermore, it is understood that the unit cells that make up the porous metal coating 60 can have any suitable alternative geometric shapes to suit the needs of a given design.

[0034] The porous material 62 is formed from a metal powder, which may include, but is not limited to, titanium, titanium alloy, stainless steel, cobalt chromium alloy, tantalum, or niobium powder. The porous metal coating 60 has a porosity suitable for promoting bone ingrowth into the dome-shaped patella component 10 when the anterior surface 22 and pegs 24 of the solid metal base 14 are implanted onto the surgically-prepared posterior surface of a patient's patella.

[0035] In the exemplary embodiment described herein, the porous metal coating 60 is additively manufactured directly on the front surface 22 and pegs 24 of the solid metal base 14 and within the wall pockets 50. In such an embodiment, the two structures, i.e., the solid metal base 14 and the porous metal coating 60, can be manufactured simultaneously during a common additive manufacturing process. For example, the two structures can be manufactured simultaneously in a single 3D printing operation to obtain a common integral metal part that includes both structures. Alternatively, the porous metal coating 60 can be manufactured as a separate part that is fixed to the solid metal base 14.

[0036] The polymer bearing 12 can be assembled to the solid metal base 14 using a number of different techniques. One exemplary method for doing so is to use a compression molding technique. For example, the solid metal base 14 and the material from which the polymer bearing 12 is made (e.g., UHMWPE) may be placed together in a mold. These parts are then compression molded together under process parameters that melt the material from which the polymer bearing 12 is made (e.g., UHMWPE) and mechanically secure it to the solid metal base 14 by the compression molding process. As described above, the molten polymer bearing 12, once molded to the solid metal base 14, intermates with the pockets 30, 52 of the solid metal base 14. It should also be appreciated that the mold can be configured to not only mold the parts together, but also to form the rear bearing surface 16 in the polymer bearing 12.

[0037] The starting materials (e.g., polymers such as polyethylene) for use in the molding process may be provided in several different forms. For example, each of the starting materials may be provided as a preform. As used herein, the term "preform" refers to an article consolidated into a rod, sheet, block, slab, or the like, such as by ram extrusion or compression molding of polymer resin particles. The term "preform" also includes preform "packs" that may be made by intermediate machining of commercially available preforms. Polymer preforms, such as polyethylene preforms, may be provided in several different variants that have been pretreated or processed. For example, crosslinked or non-crosslinked (e.g., irradiated or non-irradiated) preforms may be utilized. Such preforms may be treated to remove (e.g., remelt or quench) or stabilize (e.g., add vitamin E as an antioxidant) any free radicals present therein. Alternatively, the preforms may not be treated in such a manner.

[0038] The starting materials (e.g., polymers and copolymers) may also be provided as powders. As used herein, "powder" refers to resin particles. As described above with respect to the preforms, the powders may be provided in a number of different variations, pretreated or pretreated. For example, crosslinked or non-crosslinked (e.g., irradiated or non-irradiated) powders may be utilized.

[0039] As shown in Figures 11 and 12, although the concepts of the present disclosure have been described herein in connection with the domed patella component 10, it should be understood that the concepts of the present disclosure may also be used in the design of the anatomical component 70. Additionally, it is contemplated that a common design of the solid metal base 14 may be used for both the domed patella component and the anatomical patella component. In such a configuration, the same solid metal base 14 is used and the type of component that is obtained is determined by the configuration of the mold used to form the polymer bearing 12.

[0040] 13 and 14, the porous metal coating 60 may be disposed in additional locations on the solid metal base 14. For example, the porous metal coating 60 may be disposed within the pockets 30, including in the open areas between adjacent pockets 30 (i.e., the areas below the sections 46 of the rear face 26 between the pockets 30). In such embodiments, the molten polymer material (e.g., UHMWPE) not only interdigitates with the structures defining the pockets 30, but also with the porous metal coating 60 within the pockets 30 when the polymer bearing 12 is molded into the solid metal base 14.

[0041] While the present disclosure has been illustrated and described in detail in the drawings and foregoing description, it is to be understood that such illustration and description are to be regarded as illustrative in nature and not restrictive, and that only exemplary embodiments have been shown and described, and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.

[0042] The present disclosure has multiple advantages that arise from various features of the methods, devices, and systems described herein. It should be noted that alternative embodiments of the methods, devices, and systems of the present disclosure may 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 may readily devise their own implementations of the methods, devices, and systems that incorporate one or more of the features of the present invention and fall within the spirit and scope of the present disclosure as defined by the appended claims.

[0043] [Embodiment] (1) An orthopedic implant, comprising: a patella component, the patella component comprising: a solid metal base including: (i) a rear base surface having a number of pockets formed therein, each of which has an undercut formed therein; and (ii) a front base surface having a number of pegs extending outwardly therefrom; a porous metal coating disposed on the front base surface and on the pegs; a polymer bearing molded to the posterior base surface of the solid metal base and having a posterior bearing surface configured to articulate with a pair of femoral condyles of a femoral component. (2) An orthopedic implant as described in embodiment 1, wherein the polymer bearing is molded within the pocket of the solid metal base. (3) a rear end of each of the pockets is defined by an opening formed in the rear base surface; a front end of each said pocket is defined by a base wall spaced forwardly from said opening; 2. An orthopedic implant as described in embodiment 1, wherein the upper and lower sides of the pocket are defined by a pair of side walls extending from the opening to the base wall, the side walls having the undercut formed therein. (4) The orthopedic implant of claim 3, wherein the surface of the sidewall defining the undercut comprises a rounded surface. (5) An orthopedic implant as described in embodiment 1, wherein the several pockets include several adjacent pockets that open into each other.

[0044] (6) the solid metal base further includes a peripheral sidewall extending between the rear base surface and the front base surface; the peripheral sidewall having a number of pockets formed therein; 2. The orthopedic implant of claim 1, wherein each of the pockets formed in the peripheral sidewall has the porous metal coating disposed therein. (7) An orthopedic implant as described in embodiment 1, wherein the patella component comprises a dome-shaped patella component. (8) An orthopedic implant as described in embodiment 1, wherein the patella component comprises an anatomical patella component. (9) The orthopedic implant of embodiment 1, wherein each of the pockets has the porous metal coating disposed therein. (10) An orthopedic implant, comprising: a patella component, the patella component comprising: a solid metal base including: (i) a rear base surface having a number of pockets formed therein; and (ii) a front base surface having a number of pegs extending outwardly therefrom, wherein: (a) a rear end of each of the pockets is defined by an opening formed in the rear base surface; (b) a front end of each of the pockets is defined by a base wall spaced forwardly from the opening; (c) upper and lower sides of the pockets are defined by a pair of side walls extending from the openings to the base wall; and (d) the number of pockets includes a number of adjacent pockets that open into one another; a porous metal coating disposed on the front base surface and on the pegs; a polymer bearing molded to the posterior base surface of the solid metal base and having a posterior bearing surface configured to articulate with a pair of femoral condyles of a femoral component.

[0045] (11) The orthopedic implant of claim 10, wherein the polymer bearing is molded into the pocket of the solid metal base. (12) The orthopedic implant of claim 10, wherein each of the pair of side walls defining the pocket defines a rounded undercut surface. (13) The solid metal base further includes a peripheral sidewall extending between the rear base surface and the front base surface; the peripheral sidewall having a number of pockets formed therein; 11. The orthopedic implant of claim 10, wherein each of the pockets formed in the peripheral sidewall has the porous metal coating disposed therein. (14) The orthopedic implant of claim 10, wherein the patella component comprises a dome-shaped patella component. (15) The orthopedic implant of claim 10, wherein the patella component comprises an anatomical patella component.

[0046] (16) The orthopedic implant of claim 10, wherein each of the pockets has the porous metal coating disposed therein. (17) A method for manufacturing a patella component, comprising the steps of: disposing a porous metal coating on (i) the front surface and (ii) the number of pegs of a solid metal base; (i) molding a polymer bearing onto a posterior surface of the solid metal base such that a portion of the anterior surface of the polymer bearing is disposed within a number of pockets formed in the posterior surface of the solid metal base, and (ii) the posterior surface of the polymer bearing forms a patella bearing surface configured to articulate with a pair of femoral condyles of a femoral component. 18. The method of claim 17, wherein disposing the porous metal coating on the front surface of the solid metal base and on the number of pegs comprises 3D printing the porous metal coating and the solid metal base as a unitary metal part. (19) Some sidewalls defining the pocket in the solid metal base have undercuts formed therein; 18. The method of claim 17, wherein molding the polymer bearing onto the rear surface of the solid metal base includes molding the polymer bearing onto the rear surface of the solid metal base such that a portion of the front surface of the polymer bearing is molded into the sidewall that defines the undercut of the pocket. (20) The method of embodiment 17, wherein molding the polymer bearing onto the posterior surface of the solid metal base includes molding the polymer bearing onto the posterior surface of the solid metal base such that the posterior surface of the polymer bearing forms a dome-shaped patella bearing surface configured to articulate with the pair of femoral condyles of the femoral component.

[0047] (21) The method of embodiment 17, wherein molding the polymer bearing onto the posterior surface of the solid metal base includes molding the polymer bearing onto the posterior surface of the solid metal base such that the posterior surface of the polymer bearing forms an anatomical patella bearing surface configured to articulate with the pair of femoral condyles of the femoral component.

Claims

1. 1. An orthopedic implant comprising: a patella component, the patella component comprising: a solid metal base including: (i) a rear base surface having a plurality of pockets formed therein, each pocket having an undercut formed therein; and (ii) a front base surface having a plurality of outwardly extending pegs; a porous metal coating disposed on the front base surface and on the pegs; a polymer bearing molded to the posterior base surface of the solid metal base and having a posterior bearing surface configured to articulate with a pair of femoral condyles of a femoral component; the solid metal base further includes a peripheral sidewall extending between the rear base surface and the front base surface; the peripheral sidewall having a plurality of pockets formed therein; An orthopaedic implant, wherein each of the pockets formed in the peripheral sidewall has the porous metal coating disposed therein.

2. The orthopedic implant of claim 1 , wherein the polymer bearing is molded into the pocket of the solid metal base.

3. a rear end of each of the pockets is defined by an opening formed in the rear base surface; a front end of each said pocket is defined by a base wall spaced forwardly from said opening; The orthopedic implant of claim 1 , wherein upper and lower sides of the pocket are defined by a pair of side walls extending from the opening to the base wall, the side walls having the undercut formed therein.

4. The orthopaedic implant of claim 3 , wherein the surface of the sidewall defining the undercut comprises a rounded surface.

5. An orthopedic implant as described in claim 1, wherein the plurality of pockets in the posterior base surface include a plurality of adjacent pockets that open into one another.

6. The orthopaedic implant of claim 1 , wherein the patella component comprises a dome-shaped patella component.

7. The orthopaedic implant of claim 1 , wherein each of the pockets has the porous metal coating disposed therein.

8. 1. An orthopedic implant comprising: a patella component, the patella component comprising: a solid metal base including: (i) a rear base surface having a plurality of pockets formed therein; and (ii) a front base surface having a plurality of pegs extending outwardly therefrom, wherein: (a) a rear end of each said pocket is defined by an opening formed in said rear base surface; (b) a front end of each said pocket is defined by a base wall spaced forwardly from said opening; (c) upper and lower sides of each said pocket are defined by a pair of side walls extending from said openings to said base wall; and (d) said plurality of pockets includes a plurality of adjacent pockets that open into one another; a porous metal coating disposed on the front base surface and on the pegs; a polymer bearing molded to the posterior base surface of the solid metal base and having a posterior bearing surface configured to articulate with a pair of femoral condyles of a femoral component; the solid metal base further includes a peripheral sidewall extending between the rear base surface and the front base surface; the peripheral sidewall having a plurality of pockets formed therein; An orthopaedic implant, wherein each of the pockets formed in the peripheral sidewall has the porous metal coating disposed therein.

Images