CN220477701U - Orthopedic knee implant - Google Patents

Abstract

An orthopaedic knee implant (10) includes a femoral component (12) having a base (60) and a coating (58) disposed on a surface of the base. A method for manufacturing a femoral component of an orthopaedic knee implant is also disclosed.

Description

Orthopedic knee implant

The present application claims priority from U.S. provisional application 62/978,534 filed on month 2 and 19 of 2020, U.S. provisional application 62/978,537 filed on month 2 and 19 of 2020, and U.S. provisional application 63/010,300 filed on month 4 and 15 of 2020, each of which is incorporated herein by reference.

Cross Reference to Related Applications

Cross-reference is made to co-pending International application Ser. No. PCT/IB2021/051431, entitled "COATED IMPLANT AND METHOD OF MAKING THE SAME" and U.S. application Ser. No. 17/179827, entitled "COATED IMPLANT AND METHOD OF MAKING THE SAME", each OF which are hereby incorporated by reference.

Technical Field

The present disclosure relates generally to implantable orthopaedic prostheses, and more particularly to femoral components of implantable orthopaedic prostheses.

Background

Arthroplasty is a well known surgical procedure by which a diseased and/or damaged natural joint can be replaced with a prosthetic joint. A typical knee prosthesis includes a patella prosthetic component, a tibial tray, a femoral component, and a tibial bearing positioned between the tibial tray and the femoral component. The femoral component is designed to be attached to a surgically-prepared distal end of a patient's femur. The tibial tray is designed to be attached to a surgically-prepared proximal end of a patient's tibia.

The femoral component and tibial tray may be made of a biocompatible material, such as a cobalt chrome metal alloy. The tibial bearing component disposed between the femoral component and the tibial tray may be formed of a plastic material, such as polyethylene. However, cobalt alloys tend to be expensive and therefore require a component made of non-cobalt metallic materials and a method of making the same. For example, there is a need for a femoral component of a knee prosthesis made of non-cobalt metallic materials and a method of making the same.

Disclosure of Invention

According to one aspect of the present disclosure, an orthopedic implant includes a femoral component. The femoral component may be configured to be coupled to a distal end of a femur of a patient. The femoral component includes a substrate comprising a titanium alloy. Illustratively, the base has a condyle surface curved in a longitudinal split plane and a bone-facing surface positioned opposite the condyle surface. An articulating layer (also referred to as a "coating") is disposed on the condyle surface. The coating includes a first layer (also referred to as a "tie layer" or "inner layer") comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, or a combination thereof. The coating also includes a second layer (also referred to as an "intermediate layer") comprising a plurality of alternating sublayers. The coating further includes a third layer (also referred to as an "outer layer" or "outer ceramic layer") comprising zirconia, niobia, zirconium oxynitride, niobium oxynitride, titanium, or a combination thereof. The first layer extends between and interconnects the second layer and the condyle surface. The second layer extends between and interconnects the first layer and the third layer. The third layer forms the outer articular surface of the femoral component.

In some embodiments, the second layer may include at least eight sublayers of alternating zirconium nitride and niobium nitride sublayers. In some embodiments, each zirconium nitride sub-layer of the alternating sub-layers may have a thickness of about 0.5nm to about 200 nm. In some embodiments, the second layer may have a thickness of about 3 μm to about 6 μm.

In some embodiments, the third layer may comprise at least about 90% monoclinic oxidized zirconium. In some embodiments, the third layer may have a thickness of about 100nm to about 5 μm.

In some embodiments, at least one sub-layer of the second layer may comprise at least about 95% zirconium nitride.

In some embodiments, at least one sub-layer of the second layer may have a thickness of about 5nm to about 500 nm. In some embodiments, at least one sub-layer of the second layer may comprise at least about 95% niobium nitride.

In some embodiments, the first layer may comprise at least about 90% zirconium. In some embodiments, the first layer may have a thickness of about 50nm to about 1 μm.

Illustratively, the femoral component may include a bone engaging layer disposed on a bone-facing surface. In some embodiments, the bone engaging layer may be porous.

In some embodiments, the second layer may include an inner sublayer and an outer sublayer. In some embodiments, the inner and outer sublayers may have the same composition. In some embodiments, the second layer may include an intermediate sub-layer having a different composition than the inner sub-layer, the outer sub-layer, or both.

In some embodiments, the third layer may be titanium zirconium nitride. In addition, in some embodiments, the atomic percent of zirconium in the third layer may be 50at% to 80at%. In some embodiments, the atomic percent of zirconium in the third layer may be 30At% to 85At%.

In some embodiments, the plurality of alternating sublayers includes a plurality of titanium zirconium nitride sublayers and a plurality of metal layers. In some embodiments, the atomic percent of zirconium in the plurality of alternating sublayers is from 30At% to 85At%. In addition, in some embodiments, the atomic percent of the zirconium-titanium alloy in the plurality of alternating sublayers is from 30at% to 85at%.

According to another aspect, a process for forming a femoral component of an orthopedic knee implant includes depositing a first layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, or a combination thereof, on a condyle surface of a substrate. The substrate comprises titanium. The condyle surface is curved in the longitudinal split plane. In some embodiments, the process includes depositing a second layer including a plurality of alternating sublayers.

In some embodiments, the process can include oxidizing a portion of the second layer to form a third layer comprising oxidized zirconium.

In some embodiments, the alternating sublayers may include sublayers of zirconium nitride and sublayers of niobium. In some embodiments, depositing a plurality of alternating sublayers to form a second layer may include (a) creating a sublayer of zirconium nitride on the first layer, (b) creating a sublayer of niobium on the sublayer of zirconium nitride, and (c) repeating steps (a) and (b) to form the second layer.

In some embodiments, the process may include depositing a third layer on the outer surface of the second layer. In some embodiments, the third layer may comprise zirconia, niobia, zirconia oxynitride, niobia oxynitride, or combinations thereof.

Additional embodiments are also contemplated.

Clause 1. An orthopedic knee implant comprising: a femoral component configured to be coupled to a distal end of a femur of a patient, the femoral component comprising: (i) A substrate comprising a titanium alloy, the substrate having (a) a condyle surface curved in a longitudinal split plane and (b) a bone-facing surface positioned opposite the condyle surface; and (ii) a coating disposed on the condyle surface, the coating comprising (a) a first layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, or a combination thereof, (b) a second layer comprising a plurality of alternating sublayers, and (c) a third layer comprising (i) a tetragonal zirconia layer and (ii) a monoclinic zirconia layer, wherein (i) the first layer extends between and interconnects the second layer and the condyle surface, (ii) the second layer extends between and interconnects the first layer and the third layer, and (iii) the third layer forms an outer surface of the coating.

Clause 2. The orthopedic knee implant of clause 1, wherein the second layer further comprises a sub-layer comprising zirconium.

Clause 3 the orthopedic knee implant of clause 2, wherein each of the zirconium sublayers comprises at least about 70% tetragonal zirconium.

Clause 4 the orthopedic knee implant of any of clauses 1-3, wherein the second layer includes a first zirconium nitride sub-layer and at least nine alternating sub-layers of niobium nitride sub-layers, zirconium sub-layers, and zirconium nitride sub-layers.

Clause 5 the orthopedic knee implant of any of clauses 1-4, wherein the tetragonal zirconia layer extends between and interconnects the monoclinic zirconia layer and the second layer.

Clause 6 the orthopedic knee implant of any of clauses 1-5, wherein the third layer has a thickness of about 2 μιη to about 5 μιη.

Clause 7 the orthopedic knee implant according to any of clauses 1-6, wherein the tetragonal zirconia layer has a thickness of about 200nm to about 3 μm.

Clause 8 the orthopedic knee implant of any of clauses 1-7, wherein the monoclinic zirconia layer has a thickness of about 200nm to about 3 μm.

Clause 9 the orthopedic knee implant according to any of clauses 1-8, wherein the second layer has a thickness of about 3 μm to about 6 μm.

The orthopedic knee implant of any of clauses 1-9, wherein the second layer comprises zirconium nitride sublayers, each having a thickness of about 10nm to about 200 nm.

Clause 11 the orthopedic knee implant of any of clauses 4-10, wherein each zirconium nitride sub-layer comprises at least about 95% zirconium nitride.

The orthopedic knee implant of any of clauses 1-11, wherein the second layer comprises niobium nitride sublayers, each having a thickness of about 10nm to about 200 nm.

Clause 13 the orthopedic knee implant of any of clauses 4-12, wherein each niobium nitride sub-layer comprises at least about 95% niobium nitride.

The orthopedic knee implant of any of clauses 1-13, wherein the second layer comprises zirconium sublayers, each having a thickness of about 10nm to about 200 nm.

Clause 15 the orthopedic knee implant of any of clauses 4-14, wherein each zirconium sub-layer comprises at least about 95% zirconium.

Clause 16 the orthopedic knee implant of any of clauses 1-14, wherein the first layer comprises at least about 90% zirconium.

Clause 17 the orthopedic knee implant of any of clauses 1-16, wherein the first layer has a thickness of about 50nm to about 1 μιη or about 1 μιη to about 3 μιη.

Clause 18 the orthopedic knee implant according to any of clauses 1-17, wherein the femoral component includes a bone engaging layer disposed on the bone-facing surface.

Clause 19 the orthopedic knee implant of clause 18, wherein the bone engaging layer is porous.

Clause 20. A process for forming a femoral component of an orthopedic knee implant, the process comprising: i) Depositing a first layer comprising zirconium on a condyle surface of a titanium substrate, wherein the condyle surface is curved in a longitudinal split plane; ii) depositing a plurality of alternating sub-layers to form a second layer; and iii) depositing a third sub-layer comprising zirconium nitride onto the second layer.

Clause 21 the process of clause 20, wherein the second depositing step comprises depositing a zirconium sub-layer.

Clause 22, an orthopedic knee implant comprising: a femoral component configured to be coupled to a distal end of a femur of a patient, the femoral component comprising: (i) A substrate comprising a titanium alloy, the substrate having (a) a condyle surface curved in a longitudinal split plane and (b) a bone-facing surface positioned opposite the condyle surface; and (ii) a coating disposed on the condyle surface, the coating comprising (a) a first layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, or combinations thereof, (b) a second layer comprising a plurality of alternating sublayers, and (c) a third layer comprising zirconium oxide, wherein (i) the first layer extends between and interconnects the second layer and the condyle surface, (ii) the second layer extends between and interconnects the first layer and the third layer, and (iii) the third layer forms an outer surface of the coating.

Clause 23 the implant of clause 22, wherein the second layer comprises at least eight alternating sublayers of zirconium nitride and niobium nitride.

Clause 24 the implant of clause 23, wherein each zirconium nitride sub-layer of the alternating sub-layers has a thickness of about 5nm to about 200 nm.

The implant of any one of clauses 22 to 24, wherein the second layer has a thickness of about 3 μm to about 6 μm.

The implant of any one of clauses 22 to 25, wherein the third layer comprises at least about 90% monoclinic oxidized zirconium.

The implant of any one of clauses 22 to 26, wherein the third layer has a thickness of about 100nm to about 5 μm.

The implant of any one of clauses 22-27, wherein at least one sub-layer of the second layer comprises at least about 95% zirconium nitride.

The implant of any one of clauses 22-28, wherein at least one sub-layer of the second layer has a thickness of about 5nm to about 500 nm.

The implant of any one of clauses 22-29, wherein at least one sub-layer of the second layer comprises at least about 95% niobium nitride.

Clause 31 the implant of any of clauses 22 to 30, wherein the first layer comprises at least about 90 percent zirconium.

The implant of any one of clauses 22 to 31, wherein the first layer has a thickness of about 50nm to about 1 μm.

Clause 33 the implant of any of clauses 22 to 32, wherein the femoral component comprises a bone engaging layer disposed on the bone facing surface.

Clause 34 the implant of clause 33, wherein the bone engaging layer is porous.

The implant of any one of clauses 22-34, wherein the second layer comprises an inner sub-layer and an outer sub-layer.

Clause 36 the implant of clause 35, wherein the inner and outer sublayers have the same composition.

The implant of any one of clauses 35 to 36, wherein the second layer comprises an intermediate sub-layer having a different composition than the inner sub-layer, the outer sub-layer, or both.

Clause 38 a process for forming a femoral component of an orthopedic knee implant, the process comprising: depositing a first layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, or combinations thereof on a condyle surface of a substrate comprising titanium, wherein the condyle surface is curved in a longitudinal split plane; and depositing a second layer comprising a plurality of alternating sublayers.

Clause 39 the process of clause 38, comprising oxidizing a portion of the second layer to form a third layer.

Clause 40 the process of any of clauses 38 to 39, wherein the alternating sublayers comprise sublayers of zirconium nitride and sublayers of niobium nitride.

Clause 41 the process of any of clauses 38 to 40, comprising depositing a third layer on the outer surface of the second layer.

Clause 42 the process of clause 41, wherein the third layer comprises zirconium nitride, titanium zirconium nitride, zirconium oxide, niobium oxide, zirconium oxynitride, niobium oxynitride, or combinations thereof.

Clause 43 an orthopedic knee implant comprising: a femoral component configured to be coupled to a distal end of a femur of a patient, the femoral component comprising: (i) A substrate comprising a titanium alloy, the substrate having (a) a condyle surface curved in a longitudinal split plane and (b) a bone-facing surface positioned opposite the condyle surface; and (ii) a coating disposed on the condyle surface, the coating comprising (a) a first layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, or combinations thereof, (b) a second layer comprising a plurality of alternating sublayers grouped together in two or three layers, and (c) a third layer comprising oxidized zirconium, wherein (i) the first layer extends between and interconnects the second layer and the condyle surface, (ii) the second layer extends between and interconnects the first layer and the third layer, and (iii) the third layer forms an outer surface of the coating.

Clause 44 the implant of clause 43, wherein the second layer comprises at least 12 bilayers, and wherein each sub-layer within a bilayer has a similar thickness.

Clause 45 the implant of clause 44, wherein each sub-layer has a thickness of about 5nm to about 200 nm.

The implant of any one of clauses 43 to 45, wherein the second layer has a thickness of about 3 μm to about 8 μm.

The implant of any one of clauses 43-46, wherein the third layer comprises at least about 90% monoclinic oxidized zirconium.

The implant of any one of clauses 43 to 47, wherein the third layer has a thickness of about 100nm to about 5 μm.

Clause 49 the implant of clause 43, wherein the second layer comprises at least 8 three layers, and wherein each sub-layer within the three layers has a similar thickness.

Clause 50 the implant of clause 49, wherein each sub-layer has a thickness of about 5nm to about 500 nm.

Clause 51 the implant of clause 43, wherein the second layer comprises at least 12 bilayers, and wherein each sub-layer within a bilayer has a different thickness, and wherein all bilayers have a uniform thickness.

Clause 52 the implant of clause 43, wherein the second layer comprises at least 8 three layers, and wherein each sub-layer within the three layers has a different thickness, and wherein all three layers have a uniform thickness.

The implant of any one of clauses 43 to 52, wherein the first layer has a thickness of about 50nm to about 1 μιη or 100nm to 2 μιη.

Clause 54 the implant of any of clauses 43 to 53, wherein the femoral component comprises a bone engaging layer disposed on the bone facing surface.

Clause 55 the implant of clause 54, wherein the bone engaging layer is porous.

Clause 56 the implant of clause 51, wherein each bilayer comprises a first sublayer and a second sublayer, and the first sublayer has a thickness reduced by between 1% and 20% in each subsequent bilayer and the second sublayer has a thickness increased by between 1% and 20% in each subsequent bilayer.

Clause 57 the implant of clause 56, wherein the first sub-layer comprises at least 55% of the second layer.

Clause 58 the implant of any of clauses 43 to 57, wherein the second layer comprises a metal sub-layer selected from the group consisting of niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, and combinations thereof; a ceramic sub-layer comprising niobium, zirconium, titanium, tantalum, molybdenum, platinum, or a combination thereof; and a third layer selected from the group consisting of zirconia, niobia, titanium nitride, titanium zirconium nitride, and combinations thereof.

Clause 59 the implant of clause 43, wherein the third layer comprises titanium zirconium nitride.

Clause 60. A process for forming a femoral component of an orthopedic knee implant, the process comprising: depositing a first layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, or a combination thereof, on a condyle surface of a substrate comprising titanium, wherein the condyle surface is curved in a longitudinal split plane; and depositing a plurality of alternating sublayers to form a second layer.

Clause 61 the process of clause 60, comprising oxidizing a portion of the second layer to form a third layer comprising oxidized zirconium.

Clause 62. The process of clause 61, wherein the alternating sublayers comprise sublayers of zirconium nitride and sublayers of niobium nitride.

Clause 63. The process of any of clauses 60 to 62, comprising depositing a third layer on the outer surface of the second layer.

Clause 64 the process of clause 63, wherein the third layer comprises zirconium nitride, titanium zirconium nitride, zirconium oxide, niobium oxide, zirconium oxynitride, niobium oxynitride, or combinations thereof.

Clause 65 an orthopedic knee implant comprising: a femoral component configured to be coupled to a distal end of a femur of a patient, the femoral component comprising: (i) A substrate comprising a titanium alloy, the substrate having (a) a condyle surface curved in a longitudinal split plane and (b) a bone-facing surface positioned opposite the condyle surface; and (ii) a coating disposed on the condyle surface, the coating comprising (a) a first layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, or combinations thereof, (b) an outer ceramic third layer, and (c) a plurality of alternating sublayers positioned between and interconnecting the first layer and the outer ceramic third layer, wherein (i) the plurality of alternating sublayers are configured to resist crack propagation from the outer ceramic third layer, the plurality of alternating sublayers comprise a plurality of metallic sublayers and a plurality of ceramic sublayers that are harder than the metallic sublayers, and (ii) the outer ceramic third layer forms an outer articular surface of the femoral component and is shaped to contact a concave proximal surface of a tibial bearing.

The orthopedic knee implant according to any one of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65, wherein the first and second sub-layers form a bilayer comprising niobium and zirconium nitride, and the third layer comprises zirconium nitride.

Clause 67 the orthopedic knee implant of any of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52), and 65, wherein the first and second sub-layers form a bilayer comprising niobium and zirconium nitride, and the third layer comprises titanium zirconium nitride.

The orthopedic knee implant according to any one of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65, wherein the first and second sub-layers form a bilayer comprising zirconium nitride and zirconium, and the third layer comprises zirconium nitride.

The orthopedic knee implant according to any one of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65, wherein the first and second sub-layers form a bilayer comprising zirconium nitride and zirconium, and the third layer comprises titanium zirconium nitride.

The orthopedic knee implant according to any one of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65, wherein the first and second sub-layers form a bilayer comprising zirconium titanium and titanium zirconium nitride, and the third layer comprises titanium zirconium nitride.

Clause 71 the orthopedic knee implant according to any of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65-70, wherein the third layer comprises zirconium nitride.

The orthopedic knee implant according to any one of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65-70, wherein the third layer comprises titanium zirconium nitride.

Clause 73 the orthopedic knee implant according to any of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65-70, wherein the intermediate layer comprises a plurality of alternating titanium zirconium nitride sublayers and zirconium titanium alloy metal sublayers.

The orthopedic knee implant according to any one of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65-70, wherein the intermediate layer comprises a plurality of alternating zirconium nitride sublayers and zirconium titanium alloy sublayers.

The orthopedic knee implant according to any one of clauses 1-19, 22-37, 43-59 (but not clauses 49 or 52) and 65-70, wherein the third layer comprises a ceramic.

Clause 76 the orthopedic knee implant according to any of clauses 1-19, 22-37, 43-59, and 65-75, wherein the plurality of alternating sublayers are grouped by bilayer or trilayer.

Clause 77 the orthopedic knee implant of clause 76, wherein each bilayer or each trilayer has a thickness consistent with the other grouped sublayers in the intermediate layer, but the individual thickness of each sublayer within the group varies.

Clause 78 the orthopedic knee implant of any of clauses 1-19, 22-37, 43-59, and 65-77, wherein the third layer is titanium zirconium nitride.

Clause 79 the orthopedic knee implant of clause 78, wherein the atomic percent of zirconium in the third layer is 50at% to 80at%.

Clause 80. The orthopedic knee implant of clause 78, wherein the atomic percent of zirconium in the third layer is 30at% to 85at%.

Clause 81 the orthopedic knee implant of clauses 1-19, 22-37, 43-59, and 65-80, wherein the plurality of alternating sublayers comprises a plurality of titanium zirconium nitride sublayers and a plurality of metal layers.

Clause 82 the orthopedic knee implant of clause 81, wherein the atomic percent of zirconium in the plurality of alternating sublayers is from 30at% to 85at%.

Clause 83 the orthopedic knee implant of clause 81, wherein the atomic percent of the zirconium-titanium alloy in the plurality of alternating sublayers is from 30at% to 85at%.

Drawings

The specific embodiments are specifically directed to the following figures, wherein:

FIG. 1 is an exploded perspective view of an orthopaedic knee prosthesis showing a femoral component, a tibial bearing, and a tibial tray;

FIG. 2 is a cross-sectional view of the femoral component and tibial bearing of FIG. 1 taken in a longitudinal plane generally along line 2-2 of FIG. 1, as viewed in the direction of the arrows, note that the porous metal coating is not shown in the cross-section of FIG. 2 for clarity of description;

FIG. 3 is an enlarged cross-sectional view taken from FIG. 2, as indicated by the encircled area;

FIG. 4 is an illustrative diagrammatic view of a process for forming a coating of the femoral component of FIGS. 1-3;

FIG. 5 is an illustrative view of an embodiment of a femoral component comprising a base, an adhesive layer, an intermediate layer, and an outer layer;

FIG. 6 is an illustrative view of an embodiment of a femoral component;

FIG. 7 is an illustrative view of an embodiment of a femoral component;

FIG. 8 is an illustrative view of an embodiment of a femoral component;

FIG. 9 is an illustrative view of an embodiment of a femoral component;

FIG. 10 is an illustrative view of an embodiment of a femoral component;

FIG. 11 is an illustrative view of an embodiment of a femoral component;

FIG. 12 is an illustrative view of an embodiment of a femoral component;

FIG. 13 is an illustrative view of an embodiment of a femoral component;

FIG. 14 is an illustrative view of an embodiment of a femoral component;

FIG. 15 is an illustrative view of an embodiment of a femoral component;

FIG. 16 is an SEM image of a FIB cross section of ML-nom;

FIG. 17 is an SEM image of a FIB cross section of an MLG-nom;

FIG. 18 is a graph showing the minimum load applied by a 20 micron tip to observe first fracture or delamination in various coating samples;

FIG. 19 is an SEM image of a FIB cross-section of ML-Nom;

FIG. 20 is an SEM image of a cross section of the FIB of Mono-10; and is also provided with

Fig. 21 is a graph showing the minimum load applied by a 200 micron tip to observe first fracture or delamination in various coating samples.

Detailed Description

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 will herein be described in detail. It should be understood, however, that there is no intention to limit the concepts of the present disclosure to the specific 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.

Throughout this specification, when referring to the orthopedic implants or orthopedic prostheses described herein and to the natural anatomy of a patient, terms that represent anatomical references, such as anterior, posterior, medial, lateral, superior, inferior, and the like, may be used. These terms have well known meanings in the anatomic research and orthopedic arts. Unless otherwise indicated, these anatomical reference terms used in the written description and claims are intended to be consistent with their well-known meanings.

Referring now to fig. 1, in one embodiment, an orthopaedic knee prosthesis 10 includes a femoral component 12, a tibial bearing 14, and a tibial tray 16. The femoral component 12 is configured to articulate with a tibial bearing 14 configured to couple with a tibial tray 16. In the illustrative embodiment of fig. 1, the tibial bearing 14 is embodied as a rotating or movable tibial bearing and is configured to rotate relative to the tibial tray 16 during use. However, in other embodiments, the tibial bearing 14 may embody a fixed tibial bearing that may be constrained or limited to rotation relative to the tibial tray 16.

The tibial tray 16 is configured to be secured into a surgically-prepared proximal end of a patient's tibia (not shown). The tibial tray 16 may be secured to the patient's tibia by using bone cement or other attachment methods. The tibial tray 16 includes a platform 18 having a top surface 20 and a bottom surface 22. Illustratively, the top surface 20 is substantially planar. The tibial tray 16 also includes a stem 24 extending downwardly from the bottom surface 22 of the platform 18. A cavity or aperture 26 is defined in the top surface 20 of the platform 18 and extends downwardly into the stem 24. The aperture 26 is formed to receive a complementary stem 36 of the tibial bearing 14, as discussed in more detail below.

As described above, the tibial bearing 14 is configured to couple with the tibial tray 16. The tibial bearing 14 includes a platform 30 having an upper bearing surface 32 and a bottom bearing surface 34. In the exemplary embodiment in which the tibial bearing 14 is embodied as a rotary or movable tibial bearing, the bearing 14 includes a stem 36 extending downwardly from the bottom surface 34 of the platform 30. When the tibial bearing 14 is coupled to the tibial tray 16, the stem 36 is received in the aperture 26 of the tibial tray 16. In 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 in which the tibial bearing 14 is embodied as a fixed tibial bearing, the bearing 14 may or may not include a stem 36 and/or may include other devices or features to secure the tibial bearing 14 to the tibial tray 16 in a non-rotating configuration.

The upper bearing surface 32 of the tibial bearing 14 includes a medial bearing surface 42 and a lateral bearing surface 44. The inner and outer bearing surfaces 42, 44 are configured to receive or otherwise contact corresponding medial and lateral condyles 52, 54 of the femoral component 12, as discussed in more detail below. Thus, each of the bearing surfaces 42, 44 has a concave profile.

The femoral component 12 is configured to be coupled to a surgical preparation surface (not shown) of a distal end of a femur of a patient. The femoral component 12 may be secured to the femur of the patient using bone cement or other attachment methods. The femoral component 12 includes a pair of medial condyle 52 and lateral condyle 54. The condyles 52, 54 are spaced apart to define an intracondylar notch 56 between the two condyles. In use, the condyles 52, 54 replace the natural condyles of the patient's femur and are configured to articulate on the corresponding bearing surfaces 42, 44 of the platform 30 of the tibial bearing 14.

The exemplary orthopaedic knee prosthesis 10 (sometimes referred to as an "implant") of fig. 1 is embodied as a posterior cross-retaining knee prosthesis. That is, the femoral component 12 is embodied as a posterior cross-retaining knee prosthesis and the tibial bearing 14 is embodied as a posterior cross-retaining tibial bearing 14. However, in other embodiments, the orthopaedic knee prosthesis 10 may be embodied as a posterior cross-sacrificial knee prosthesis.

Referring now to fig. 1 and 2, the femoral component 12 is configured to articulate on the tibial bearing 14 during use. Each condyle 52, 54 of the femoral component 12 includes a lateral articular surface 50 convexly curved in a longitudinal split plane and configured to face the corresponding bearing surface 42, 44 of the tibial bearing 14.

As shown in FIG. 2, the femoral component 12 includes a base 60 and a coating 58. Illustratively, the coating 58 is disposed on the base 60 and is configured to interact with the tibial bearing 14. In some embodiments, the femoral component 12 includes a bone engaging layer 62 positioned opposite the coating 58 to position the substrate 60 therebetween. Bone engaging layer 62 is configured to interact with a surgically-prepared femur of a patient.

The base 60 includes a condyle surface 66 and a bone-facing surface 64, as shown in fig. 2. The condyle surface 66 is curved in the longitudinal split plane and is configured to position the coating 58 on the substrate 60. The bone-facing surface 64 is positioned opposite the condyle surface 66 and is disposed to face the surgically-prepared distal end of the patient's femur. In some embodiments, bone-facing surface 64 directly contacts the surgically-prepared femur bone. In some embodiments, the bone engaging layer 62 is coupled to a bone facing surface 64 of the base 60.

Fig. 1 and 2 illustrate a cementless embodiment of the femoral component 12 in which the bone engaging layer 62 is configured to be implanted without cement between the femoral component 12 and a surgically-prepared distal end of a patient's femur. In some embodiments, bone engaging layer 62 comprises titanium. It should be appreciated that bone engaging layer 62 may be a separately applied coating, such as that commercially available from DePuy Synthesis (Warsaw, indiana) A porous coating.

In some embodiments, bone engaging layer 62 may be defined by a porous three-dimensional structure formed by a plurality of interconnected struts. In one example, the plurality of interconnected struts form a plurality of geometries, which in the illustrative embodiment are diamond-shaped trigonal aspects. It should be appreciated that such geometries may be varied to suit the needs of a given design. Furthermore, it should be appreciated that bone engaging layer 62 may be formed from any other alternative geometry suitable to suit the needs of a given design.

In some embodiments, bone engaging layer 62 is formed from a metal powder. Illustratively, the metal powder may include, but is not limited to, titanium alloys, stainless steel, cobalt chromium alloys, tantalum, niobium, or combinations thereof. The bone engaging layer 62 has a porosity suitable for promoting bone ingrowth into the bone engaging layer 62 of the femoral component 12 when implanted into a surgically-prepared surface of the distal end of the patient's femur.

In the exemplary embodiment described herein, the bone engaging layer 62 is additive manufactured directly onto the bone facing surface 64 of the femoral component 12. In such embodiments, the two structures (i.e., the femoral component 12 and the bone engaging layer 62) may be manufactured simultaneously during common additive manufacturing methods. For example, two structures may be fabricated simultaneously in a single 3D printing operation that produces a common monolithic metal assembly that includes both structures. Alternatively, the bone engaging layer 62 may be manufactured as a separate component that is secured to the bone facing surface 64 of the femoral component 12.

In an alternative embodiment, the femoral component 12 is configured to be attached to a surgically-prepared distal end of a patient's femur using cement. In some embodiments, the femoral component 12 includes a cement reservoir (not shown) disposed on the bone-facing surface 64. In some embodiments, bone cement is disposed on the bone-facing surface 64. In some embodiments, the bone cement comprises bone cement. In some embodiments, bone-facing surface 64 is configured to receive bone cement.

In some embodiments, the substrate 60 is metallic. In some embodiments, the substrate 60 comprises a metal alloy. In some embodiments, the substrate 60 comprises a titanium alloy. In some embodiments, the substrate 60 comprises titanium and vanadium. In some embodiments, the substrate 60 comprises titanium, aluminum, and vanadium. In some embodiments, the substrate 60 comprises Ti-6Al-4V. In some embodiments, the substrate 60 consists essentially of Ti-6Al-4V.

Referring now to fig. 2 and 3, a coating 58 is disposed on the condyle surface 66. Coating 58 is positioned opposite bone-facing surface 64 to position substrate 60 between the coating and the bone-facing surface. The coating 58 is configured to interact with the bearing surfaces 42, 44 and articulate with the tibial bearing 14.

The coating 58 has a plurality of layers 68, 70, 72. Layers 68, 70, 72 may each be constructed of a material having mechanical properties (e.g., enhanced wear resistance, resistance to fracture, resistance to delamination, adjustable stiffness, ductility, corrosion resistance, and oxidation resistance) that facilitate use in the construction of coating 58.

In some embodiments, the coating 58 cooperates with the base 60 to minimize scratching of the outer articular surface 50 of the femoral component 12. In some embodiments, the coating 58 cooperates with the substrate 60 to minimize cohesive fracture and delamination of the coating 58. In some embodiments, the coating 58 cooperates with the substrate 60 to resist corrosion. In some embodiments, the coating 58 provides density and toughness. In some embodiments, the coating 58 cooperates with the substrate 60 to provide sufficient toughness to minimize or avoid breakage.

Referring now to fig. 3, the coating 58 includes an inner or tie layer 68, an intermediate layer 70, and an outer layer 72. The outer layer 72, the intermediate layer 70, or both the outer layer 72 and the intermediate layer 70 of the coating 58 are constructed of materials having mechanical properties that are advantageous for use in the construction of the coating 58. For example, the intermediate layer 70 is constructed of a material that provides rigidity and ductility that diffuses the load of the force, stops cracking, and improves the adhesion of the coating 58 to the substrate 60. On the other hand, the adhesive layer 68 is constructed of a material having mechanical properties that facilitate use in securing the coating 58 to the substrate 60.

It should be understood that the term "layer" as used herein is not intended to be limited to a certain "thickness" of material positioned adjacent to another similarly sized "thickness" of material, but is intended to include a variety of structures, configurations and constructions of materials. For example, the term "layer" may include a portion, region, or other structure of material that is positioned adjacent to another portion, region, or structure of a different material. For example, although the interface between the intermediate layer 70 and the outer layer 72 is shown as being uniform in fig. 3, in some embodiments the interface is irregular such that the intermediate layer 70 and the outer layer 72 do not have a uniform thickness. In some embodiments, the "layer" is formed by modifying a surface or a portion of an existing layer. For example, in some embodiments, the outer layer 72 is formed from an exterior portion of the oxidation intermediate layer 70. In an alternative embodiment, the "layer" is formed by providing additional material to the existing surface. For example, in some embodiments, the adhesive layer 68 is formed by depositing a material onto the condyle surface 66.

As shown in fig. 3, an adhesive layer 68 is disposed on the condyle surface 66. The outer layer 72 is arranged to form the coating 58 and thus the outer articular surface 50 of the femoral component 12. An intermediate layer 70 extends between and interconnects the adhesive layer 68 and the outer layer 72. In some embodiments, the coating 58 does not include an outer layer 72 (as shown in fig. 11) such that the exposed surface of the intermediate layer 70 may be further processed to form the outer articular surface 50.

An adhesive layer 68 extends between and interconnects the intermediate layer 70 and the condyle surface 66. Inner layer 68 includes an inner surface 74 and an outer surface 76. The inner surface 74 is located between the outer surface 76 and the condyle surface 66. The outer surface 76 of inner layer 68 is located between the inner surface 74 of inner layer 68 and intermediate layer 70. In some embodiments, inner layer 68 is configured to reduce delamination of coating 58 from femoral component 12.

The adhesive layer 68 may have a particular thickness as measured from the condyle surface 66. In some embodiments, bonding layer 68 may be present at a thickness on the order of nanometers to micrometers. In some embodiments, the bonding layer 68 has a thickness of about 0.5nm to about 10nm, about 0.5nm to about 3nm, or about 5nm to about 10 nm. In some embodiments, the adhesive layer 68 has a thickness of about 0.10 μm to about 2 μm. In some embodiments, the bonding layer 68 has a thickness of about 200nm to about 1 μm. In some embodiments, the bonding layer 68 has a thickness of at least about 0.10 μm, at least about 0.20 μm, at least about 0.30 μm, at least about 0.5 μm, at least about 1 μm, at least about 1.5 μm, or at least about 2 μm. In some embodiments, the tie layer 68 has a thickness of about 200nm, about 220nm, about 240nm, about 260nm, about 280nm, about 300nm, about 320nm, about 340nm, about 360nm, about 38nm, about 400nm, about 420nm, about 440nm, about 460nm, about 480nm, about or about 500 nm.

The bonding layer 68 may comprise a metal, alloy, or other suitable material to provide mechanical properties that are advantageous for use in securing the coating 58 to the substrate 60. For example, the composition of the tie layer 68 may be selected to minimize cohesive failure of the coating 58 during manufacture and in use. In an exemplary embodiment, the bonding layer 68 comprises niobium, zirconium, titanium, tantalum, molybdenum, platinum, hafnium, combinations thereof, or any other suitable metal. In some embodiments, the bonding layer 68 comprises zirconium. In some embodiments, the bonding layer 68 comprises at least about 90% zirconium. In some embodiments, the bonding layer 68 comprises at least about 95% zirconium. In some embodiments, the bonding layer 68 comprises at least about 90% niobium, titanium, tantalum, molybdenum, platinum, or a combination thereof. In some embodiments, the bonding layer 68 comprises at least about 95% niobium, zirconium, titanium, tantalum, molybdenum, platinum, hafnium, or a combination thereof.

As described above, the intermediate layer 70 extends between and interconnects the adhesive layer 68 and the outer layer 72. Intermediate layer 70 includes an inner surface 78 and an outer surface 80. The inner surface 78 of the intermediate layer 70 is located between the inner layer 68 and the outer surface 80 of the intermediate layer 70. The outer surface 80 of the intermediate layer 70 is located between the inner surface 78 of the intermediate layer 70 and the outer layer 72.

In some embodiments, the intermediate layer 70 has an overall thickness of about 3 μm to about 7 μm. In some embodiments, the intermediate layer 70 has an overall thickness of about 3 μm to about 8 μm. In some embodiments, the intermediate layer 70 has an overall thickness of about 5nm to about 5 μm. In some embodiments, the intermediate layer 70 has an overall thickness of about 1.5 μm to about 2.0 μm. In some embodiments, the intermediate layer 70 has an overall thickness of at least about 50nm, at least about 100nm, at least about 200nm, at least about 0.5 μm, at least about 1 μm, at least about 2 μm, at least about 3 μm, or at least about 4 μm. In some embodiments, the intermediate layer 70 has an overall thickness of about 3.2 μm, about 3.5 μm, about 4.0 μm, about 4.2 μm, about 4.3 μm, about 4.5 μm, about 5.0 μm, about 5.3 μm, about 5.5 μm, about 6.0 μm, about 6.3 μm, about 6.4 μm, or about 6.5 μm.

The intermediate layer 70 may be formed of a plurality of sublayers. The sequence and composition of the sublayers 86, 88, 90 are configured to distribute the load and stop cracking that may occur. In the illustrated embodiment, intermediate layer 70 is formed from an inner sublayer 86, an intermediate sublayer 88, and an outer sublayer 90. In some exemplary embodiments, some or all of the sublayers 86, 88, 90 are repeated such that the intermediate layer 70 may include two or more of one of the sublayers.

The sublayers 86, 88, 90 may comprise metals, alloys, ceramics, or other suitable materials as described herein. Illustratively, various combinations of sublayers 86, 88 or 90 provide fracture toughness and corrosion resistance. For example, each of the sublayers 86, 88, and 90 may comprise niobium, zirconium, titanium, tantalum, hafnium, molybdenum, platinum, combinations thereof, or any other suitable metal, including alloys thereof. Each of the sublayers 86, 88 and 90 may comprise a ceramic including niobium, zirconium, titanium, tantalum, molybdenum, platinum, combinations thereof, or any other suitable ceramic. Illustratively, the ceramic may include metals and nitrides, carbides, oxides, or combinations thereof. For example, the ceramic may include zirconium nitride, titanium zirconium nitride, zirconium oxide, or niobium nitride.

In some embodiments, the plurality of alternating sublayers includes a plurality of titanium zirconium nitride sublayers and a plurality of metal layers. In some embodiments, the atomic percent of zirconium in the plurality of alternating sublayers is from 30At% to 85At%. In some embodiments, the atomic percent of zirconium in the plurality of alternating sublayers is about 30At%, about 35At%, about 40At%, about 45At%, about 50At%, about 55At%, about 60At%, about 65At%, about 70At%, about 75At%, about 80At%, or about 85At%. In addition, in some embodiments, the atomic percent of the zirconium-titanium alloy in the plurality of alternating sublayers is from 30at% to 85at%. In some embodiments, the atomic percent of the zirconium-titanium alloy in the plurality of alternating sublayers is about 30At%, about 35At%, about 40At%, about 45At%, about 50At%, about 55At%, about 60At%, about 65At%, about 70At%, about 75At%, about 80At%, or about 85At%.

In an exemplary embodiment, some or all of the sublayers 86, 88, 90 may participate in a superlattice with an adjacent layer or sublayer. In some implementations, each of the sublayers 86, 88, 90 has a thickness of about 0.5nm to about 10nm, about 5nm to about 10nm, or about 0.5nm to about 3 nm. In some implementations, each of the sublayers 86, 88, 90 has a thickness of about 5nm to about 500 nm.

The intermediate layer 70 may comprise two different sub-layers, which may be alternately stacked. Referring to fig. 5, for example, intermediate layer 70 may include an inner sublayer 86, an intermediate sublayer 88, and an outer sublayer 90. The composition of the inner sublayer 86, the intermediate sublayer 88, and the outer sublayer 90 may be the same or different. For example, intermediate layer 70 may include a sequence of two sublayers, such as an inner sublayer 86 and an intermediate sublayer 88, having a composition of-A-B-or (-A-B-) _n Wherein each of a and B is a different composition and n is at least 1, at least 2, at least 4, or at least 10. In this embodiment, the inner sublayer 86 is a and the intermediate sublayer 88 is B. For example, where there are two repetitions of sub-layers, such as A-B-A-B-A-B, each A-B may be referred to as ase:Sub>A "bilayer". Thus, a bilayer is a grouping of two sublayers. In some embodiments, the composition of layer a comprises zirconium nitride. In some embodiments, the composition of layer B includes niobium nitride, tantalum nitride, hafnium nitride, niobium, tetragonal and/or monoclinic zirconium, tantalum, titanium or hafnium. In some embodiments, the number of alternating sublayers is selected such that the intermediate layer 70 achieves an overall thickness of, for example, up to about 2 μm, up to about 4 μm, up to about 6 μm, or up to about 8 μm.

Alternatively, the intermediate layer 70 may have a sequence of two repeating sublayers, such as an inner sublayer 86 and an intermediate sublayer 88, and an outer sublayer 90, as shown in fig. 3 and 5. In some examples, intermediate layer 70 includes the sequence A- (B-A) _n -C-, comprising repeating inner sub-layer 86 and intermediate sub-layer 88, wherein each of a and B is a different composition and n is at least 1, at least 2, at least 4, or at least 10, and wherein C is outer sub-layer 90 and has the same composition as one of inner sub-layer 86 or intermediate sub-layer 88. In some embodiments, the composition of layer a comprises zirconium nitride. In some embodiments, the composition of layer B includes niobium nitride, tantalum nitride, hafnium nitride, niobium, tetragonal and/or monoclinic zirconium, tantalum, titanium or hafnium. In some embodimentsWherein the outer sublayer 90 comprises zirconium nitride. In some embodiments, intermediate layer 70 comprises a repeat of: i) A sub-layer of zirconium nitride, ii) a sub-layer of niobium, tetragonal and/or monoclinic zirconium, tantalum, titanium, hafnium, niobium nitride, tantalum nitride or hafnium nitride, and iii) an outer sub-layer of zirconium nitride 90. In some embodiments, the number of alternating sublayers is selected such that the intermediate layer 70 reaches a thickness of, for example, up to about 5 μm.

Alternatively, intermediate layer 70 may have a sequence of three repeating sublayers, such as inner sublayer 86, intermediate sublayer 88, and outer sublayer 90. In some examples, intermediate layer 70 includes a repeating sequence of inner sublayer 86, intermediate sublayer 88, and outer sublayer 90, the repeating sequence having a composition of- (A-B-C) _n -, wherein each of A, B and C is a different composition, and n is at least 1, at least 2, at least 4, or at least 10. In this embodiment, inner sublayer 86 is a, intermediate sublayer 88 is B, and outer sublayer 90 is C. For example, where there are three repetitions of sub-layers, such as A-B-C-A-B-C-A-B-C, each A-B-C may be referred to as se:Sub>A "tri-layer". Thus, three layers are groupings of three sub-layers. It should be noted that although the formulse:Sub>A shows se:Sub>A sequence of A-B-C, any arrangement of sub-layer sequences is contemplated, such as A-C-B, B-C-A, etc. It should further be noted that the intermediate layer 70 may comprise more than one sub-layer sequence, such as the sequence of-A-B-C-B-C-A-etc. It should be further noted that the intermediate layer 70 may comprise more than one sub-layer sequence, such as the sequence of-A-B-A-B-A-B-A-C-A-C-etc. It should be further noted that the intermediate layer 70 may comprise more than one sub-layer sequence, such as the sequence of-A-B-A-C-A-B-A-C-etc. Referring to FIG. 13, for example, intermediate layer 70 may comprise a material having a composition of-A-B-or (-A-B-) _n Wherein each of a and B is of a different composition and n is at least 1, at least 2, at least 4 or at least 10; having the composition-A-C-or (-A-C-) _n Wherein each of a and C is of a different composition and n is at least 1, at least 2, at least 4 or at least 10. Illustratively, either of the compositions A, B or C may include niobium nitride, tantalum nitride, hafnium nitride, zirconium nitride, niobium, tetragonal and/or monoclinic zirconium, tantalum, titanium, orHafnium.

In some embodiments, the intermediate layer 70 includes a zirconium nitride inner sub-layer 86, a niobium nitride intermediate sub-layer 88, and a zirconium nitride outer sub-layer 90. In some embodiments, the intermediate layer 70 includes at least one inner sub-layer 86 of zirconium nitride and at least one intermediate sub-layer 88 of niobium nitride. In some embodiments, the intermediate layer 70 includes a plurality of alternating sublayers of zirconium nitride and niobium nitride. In some embodiments, the intermediate layer 70 includes at least four alternating sublayers of an inner sublayer 86 of zirconium nitride and an intermediate sublayer 88 of niobium nitride. In the illustrated embodiment, a zirconium nitride outer sub-layer 90 is formed on the outermost niobium nitride intermediate sub-layer 88. It should be appreciated that while fig. 3 shows a single sub-layer of the zirconium nitride inner sub-layer 86 and a single sub-layer of the niobium nitride intermediate sub-layer 88, any number of alternating sub-layers is contemplated.

In some embodiments, inner sublayer 86 has a thickness of about 5nm to about 500 nm. In some embodiments, the inner sublayer 86 has a thickness of at least about 0.05nm, at least about 1nm, at least about 5nm, at least about 10nm, at least about 50nm, at least about 100nm, at least about 150nm, at least about 200nm, at least about 250nm, at least about 300nm, at least about 350nm, at least about 400nm, at least about 450nm, at least about 500nm, or at least about 550 nm. In some embodiments, the inner sublayer 86 has a thickness of about 1nm to about 200nm or about 5nm to about 100 nm. In some embodiments, sublayer 86 has a thickness of about 30nm, about 40nm, about 50nm, about 60nm, about 70nm, about 80nm, about 90nm, about 100nm, about 110nm, about 120nm, about 130nm, about 140nm, about 150nm, about 160nm, about 170nm, about 180nm, about 190nm, about 200nm, about 210nm, or about 220 nm. In some embodiments, the sub-layer 86 has a thickness of about 65nm, about 95nm, about 115nm, about 125nm, or about 205 nm.

In some embodiments, inner sublayer 86 comprises at least about 90% zirconium nitride. In some embodiments, inner sublayer 86 comprises at least about 95% zirconium nitride.

In some embodiments, the intermediate sublayer 88 has a thickness of about 5nm to about 500 nm. In some embodiments, the intermediate sublayer 88 has a thickness of at least about 1nm, at least about 5nm, at least about 10nm, at least about 50nm, at least about 100nm, at least about 150nm, or at least about 200nm, at least about 250nm, at least about 300nm, at least about 350nm, at least about 400nm, at least about 450nm, at least about 500nm, or at least about 550 nm. In some embodiments, sublayer 88 has a thickness of about 30nm, about 40nm, about 50nm, about 60nm, about 70nm, about 80nm, about 90nm, about 100nm, about 110nm, about 120nm, about 130nm, about 140nm, about 150nm, about 160nm, about 170nm, about 180nm, about 190nm, about 200nm, about 210nm, or about 220 nm. In some embodiments, the sublayer 88 has a thickness of about 65nm, about 95nm, about 115nm, about 125nm, or about 205 nm.

In some embodiments, the intermediate sublayer 88 comprises at least about 90% niobium nitride, tantalum nitride, hafnium nitride, niobium, tetragonal and/or monoclinic zirconium, tantalum, titanium, or hafnium. In some embodiments, the intermediate sublayer 88 comprises at least about 95% niobium nitride, tantalum nitride, hafnium nitride, niobium, tetragonal and/or monoclinic zirconium, tantalum, titanium, or hafnium.

In some embodiments, outer sublayer 90 has a thickness of about 1 μm to about 5 μm. In some embodiments, outer sublayer 90 has a thickness of about 2 μm to about 3 μm. In some embodiments, outer sublayer 90 has a thickness of at least about 0.5 μm, at least about 1 μm, at least about 1.5 μm, at least about 2 μm, at least about 2.5 μm, at least about 3 μm, at least about 3.5 μm, at least about 4 μm, at least about 4.5 μm, at least about 5 μm, or at least about 5.5 μm. In some embodiments, the outer sublayer 90 forms the outer articular surface 50 of the femoral component 12 and the coating 58.

In some embodiments, the outer sublayer 90 comprises at least about 90% zirconium nitride. In some embodiments, the outer sublayer 90 comprises at least about 95% zirconium nitride.

In some exemplary embodiments, the outer layer 72 is configured to form the coating 58 and thus the outer articular surface 50 of the femoral component 12. The outer layer 72 includes an inner surface 82 and an outer surface 84. The inner surface 82 of the outer layer 72 is located between the intermediate layer 70 and the outer surface 84 of the outer layer 72. The outer surface 84 of the outer layer 72 forms the outer surface 84 of the femoral component 12. Illustratively, the outer surface 84 of the outer layer 72 forms the outer articular surface 50 of the femoral component 12 and is configured to interact and rotate about the tibial bearing 14, as shown in fig. 2.

In some examples, outer layer 72 may be formed by depositing outer layer 72 or by thermal growth through oxidation of a portion of intermediate layer 70. In some embodiments, the outer layer 72 has a thickness of at least about 0.2 μm, at least about 0.5 μm, at least about 1 μm, at least about 2 μm, at least about 3 μm, at least about 4 μm, at least about 5 μm, or at least about 6 μm. In some embodiments, the outer layer 72 has a thickness of at least about 50nm, at least about 100nm, at least about 150nm, at least about 200nm, or at least about 250 nm. When the outer layer 72 is deposited, the outer layer 72 may have a thickness of about 0.5 μm to about 5 μm. When the outer layer 72 is formed by oxidation, the outer layer 72 may have a thickness of about 100nm to about 200 nm. In some embodiments, the outer layer 72 has a thickness of about 1000nm, about 1500nm, about 1800nm, about 1900nm, about 2000nm, about 2400nm, about 2500nm, about 2800nm, about 3000nm, about 3100nm, or about 3500 nm.

In an exemplary embodiment, the outer layer 72 is formed by oxidizing at least a portion of the intermediate layer 70. For example, the outer surface 80 of the intermediate layer 70 may be oxidized to thermally grow the outer layer 72. Illustratively, thermal growth may occur by inserting oxygen into the crystal lattice of portions (e.g., outer portions) of the intermediate layer 70 to form an oxide. In some embodiments, the outer layer 72 comprises a ceramic. In an exemplary embodiment, the ceramic of the outer layer 72 is an oxide of the composition of the intermediate layer 70. In some embodiments, the outer layer 72 comprises an oxide of a niobium and zirconium alloy. In some embodiments, the outer layer 72 comprises zirconia. In some embodiments, the outer layer 72 comprises niobium oxide. In some embodiments, the outer layer 72 comprises zirconium oxide and niobium oxide. In some embodiments, the outer layer 72 comprises monoclinic zirconia. In some embodiments, the outer layer 72 comprises at least about 90% zirconia. In some embodiments, the outer layer 72 comprises at least about 90% monoclinic zirconia. In some embodiments, the outer layer 72 comprises monoclinic and/or tetragonal zirconium oxynitrides. In some embodiments, the outer layer 72 comprises at least about 5% zirconium oxynitride. In some embodiments, the outer layer 72 comprises at least about 2% tetragonal zirconia. In some embodiments, the outer layer 72 comprises at least about 2% cubic zirconia. In some embodiments, the outer layer 72 comprises a ceramic comprising titanium. In one exemplary aspect, the outer layer 72 comprises titanium zirconium nitride. In some embodiments, the outer layer 72 comprises oxidized metal and titanium.

In an exemplary embodiment, the outer layer 72 is formed by depositing the outer layer 72. In some exemplary embodiments, the outer layer 72 comprises deposited zirconia. The deposited zirconia of the outer layer 72 may be tetragonal zirconia or monoclinic zirconia. In an exemplary embodiment, when monoclinic zirconia is deposited, a tetragonal zirconia layer will form between the monoclinic zirconia and the intermediate layer 70. In some exemplary embodiments, the outer layer 72 is formed by increasing the concentration of oxygen while depositing the outermost sub-layer of the intermediate layer 70 such that the outer layer 72 is an oxide of the outermost sub-layer of the intermediate layer 70. For example, if the outermost sub-layer (e.g., outer sub-layer 90) of intermediate layer 70 is zirconium nitride, outer layer 72 may be formed by increasing the concentration of deposited oxygen to form oxidized zirconium nitride (sometimes referred to as zirconium oxynitride). In some embodiments, the outer layer 72 may comprise zirconium oxynitride and niobium oxynitride.

In some embodiments, the third layer may be titanium zirconium nitride. In addition, in some embodiments, the atomic percent of zirconium in the third layer may be 50at% to 80at%. In some embodiments, the atomic percent of zirconium in the third layer may be about 50At%, about 55At%, about 60At%, about 65At%, about 70At%, about 75At%, or about 80At%. In some embodiments, the atomic percent of zirconium in the third layer may be 30At% to 85At%. In some embodiments, the atomic percent of zirconium in the third layer may be about 30At%, about 35At%, about 40At%, about 45At%, about 50At%, about 55At%, about 60At%, about 65At%, about 70At%, about 75At%, about 80At%, or about 85At%.

In some embodiments, the bonding layer 68 comprises zirconium, the intermediate layer 70 comprises at least one zirconium nitride sub-layer 86 and at least one niobium nitride sub-layer 88, and the outer layer 72 comprises zirconium oxide.

Referring now to fig. 4, the femoral component 12 of the orthopaedic knee prosthesis 10 may be formed by a process 100. In some embodiments, process 100 includes a first deposition step 110 of depositing tie layer 68, a second deposition step 120 of depositing intermediate layer 70, and an oxidation step 130. In an exemplary embodiment, the process 100 includes a step of preparing the substrate 60 for the deposition step 110. In some embodiments, the process 100 includes a finishing step, such as polishing, after the oxidizing step 130.

Referring now to fig. 6-9, an exemplary illustrative embodiment of the femoral component 12 is shown. Illustratively, as shown in fig. 6-9, a represents a sub-layer and is shown in an optionally repeated stack of sub-layers with zirconium nitride.

Referring now to fig. 10-15, an exemplary illustrative embodiment of the femoral component 12 is shown. In each example, a represents a portion of the substrate 60, B represents a layer or sub-layer comprising niobium, C represents a layer or sub-layer comprising zirconium nitride, one B and one C together form a bilayer, and D represents a layer comprising niobium nitride. In some embodiments, the outer layer 72 of C represents a layer comprising Ti-doped zirconium nitride. As exemplarily shown in fig. 10-15, the bonding layer 68 comprises niobium. In some embodiments, the bonding layer 68 may comprise niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, or combinations thereof.

As shown in the embodiment of fig. 10, the intermediate layer 70 includes a plurality of alternating sublayers (C and B) such that n=24, and the outer layer 72 is a single layer C. In the embodiment of fig. 11, the intermediate layer 70 is a single layer D. In this embodiment, the monolayer D may be further processed to form the outer articular surface 50 (e.g., oxidized). In the embodiment of fig. 12, the intermediate layer 70 includes a plurality of alternating sublayers (C and B) and (C and D) such that n=24, and the outer layer 72 is a monolayer C. In the embodiment of fig. 13, the intermediate layer 70 includes a plurality of alternating sublayers (C and D) and (B and C) such that n=24, and the outer layer 72 is a monolayer C. In the embodiment of fig. 14, the intermediate layer 70 includes a plurality of alternating sublayers (C-D-C-B) such that n=24, and the outer layer 72 is a monolayer C. In the embodiment of fig. 15, the intermediate layer 70 includes a plurality of alternating sublayers (C and D) such that n=24, and the outer layer 72 is a monolayer C.

The intermediate layer 70 may be a single layer, such as the layer comprising niobium nitride in fig. 11. Alternatively, the intermediate layer 70 may comprise a repeating stack of layers. In some embodiments, the intermediate layer 70 comprises a repeating stack of a sub-layer comprising zirconium nitride and a sub-layer comprising niobium, as exemplarily shown in fig. 10. In some embodiments, the intermediate layer 70 includes a first repeated stack of a sub-layer 86 comprising zirconium nitride and a sub-layer 88 comprising niobium and a second repeated stack of a sub-layer 86 comprising zirconium nitride and a sub-layer 88 comprising niobium nitride, as exemplarily shown in fig. 12 and 13. In some embodiments, the intermediate layer 70 comprises a repeating stack of a sub-layer 86 comprising zirconium nitride, a sub-layer 88 comprising niobium nitride, a sub-layer 86 comprising zirconium nitride, and a sub-layer 90 comprising niobium, as exemplarily shown in fig. 14. In some embodiments, the intermediate layer 70 includes a repeating stack of a sub-layer 86 including zirconium nitride and a sub-layer 88 including niobium nitride, as exemplarily shown in fig. 15.

In the exemplary embodiment of fig. 10-15, the adhesive layer 68 has a thickness of about 0.5 μm or about 5 μm. Each sub-layer 86 and 88 of the intermediate layer 70 (except for the sub-layer 90 furthest from the substrate) has a thickness of about 125 nm. Illustratively, each of the embodiments in fig. 10-15 includes an outer sublayer 90 of zirconium nitride having a thickness of about 3 μm. This outer layer may optionally undergo further processing to form outer layer 72.

Alternatively, the intermediate layer 70 may comprise a repeating sub-layer sequence wherein the repeat has a uniform thickness throughout the span of the intermediate layer 70, but the thickness of the individual sub-layers varies. Referring to fig. 17, sublayers 86 and 88 are stacked in a repeating sequence, where each repeat has a uniform combined thickness in intermediate layer 70, but each individual thickness of sublayer 86 or sublayer 88 varies. For example, for each subsequent sequence, the percent thickness of sub-layer 86 may be incrementally reduced and the percent thickness of sub-layer 88 may be incrementally increased. In one embodiment, sub-layer 86 may be 75% of the combined thickness of the first sequence, and sub-layer 88 may be 25% of the combined thickness of the first sequence. Then in the second sequence, sub-layer 86 may account for 70% and sub-layer 88 may account for 30%. Thereafter, the third sequence may include 65% of sub-layer 86 and 35% of sub-layer 88. In this way, sub-layers 86 and 88 are stepped over the span of intermediate layer 70. In some embodiments, the presence of sub-layer 86 in the sequence is reduced by 5% and the presence of sub-layer 88 in the sequence is increased by 5% in each subsequent sequence over the span of intermediate layer 70. Thus, each sequence of sublayers 86 and 88 maintains a uniform thickness throughout the span of intermediate layer 70. Additional exemplary embodiments are provided in tables 3, 4 and 5. In some embodiments, the amount of sublayer 86 present in a sequence is reduced by about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, or about 25% in each subsequent sequence. Conversely, in some embodiments, the sublayer 88 is present in an amount that increases by about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, or about 25% in each subsequent sequence.

In some embodiments, the first deposition step 110 deposits material and forms the adhesive layer 68 on the condyle surface 66 of the substrate 60. In some embodiments, the first deposition step 110 is performed by Physical Vapor Deposition (PVD). In some embodiments, the first deposition step 110 is performed by a magnetron sputtering system. In other embodiments, PVD may be performed using HiPIMS, IBAD, or other deposition systems.

In some embodiments, the second deposition step 120 forms the intermediate layer 70 on the outer surface 76 of the tie layer 68. In some embodiments, the second deposition step 120 is performed by PVD. In some embodiments, the depositing step 120 is performed by a magnetron sputtering system.

In some embodiments, the second deposition step 120 includes depositing the inner sub-layer 86. Illustratively, the inner sub-layer 86 is deposited onto the tie layer 68 by a second deposition step 120.

In some embodiments, the second deposition step 120 includes depositing the intermediate sub-layer 88 onto the inner sub-layer 86. In the exemplary embodiment, second deposition step 120 includes repeating the steps of depositing inner sub-layer 86 and intermediate sub-layer 88 until the desired number of sub-layers is achieved. The outer sublayer 90 may then be deposited over the outermost deposited sublayer (e.g., the inner sublayer 86 or the intermediate sublayer 88).

In some embodiments, the second deposition step 120 includes depositing the outer sublayer 90 onto the intermediate sublayer 88. In the exemplary embodiment, second deposition step 120 includes repeating the steps of depositing inner sub-layer 86, intermediate sub-layer 88, and outer sub-layer 90 until the desired number of sub-layers is achieved. Optionally, a final outer sublayer 90 is deposited over the outermost sublayer (e.g., inner sublayer 86, intermediate sublayer 88, or outer sublayer 90).

In some embodiments, the second deposition step 120 includes depositing the inner zirconium nitride sub-layer 86 onto the bonding layer 68, depositing the intermediate niobium nitride sub-layer 88 onto the inner zirconium nitride sub-layer 86, and depositing the outer zirconium nitride sub-layer 90 onto the intermediate niobium nitride sub-layer 88.

In some embodiments, a second deposition step 120 is performed to produce a plurality of alternating sublayers of the inner sublayer 86 of zirconium nitride and the intermediate sublayer 88 of niobium nitride. In some embodiments, the steps of depositing the inner zirconium nitride sub-layer 86 and the intermediate niobium nitride sub-layer 88 are repeated until the desired thickness is obtained. In some embodiments, the thickness is at most 6 μm.

In some embodiments, the second deposition step 120 deposits the outer sublayer 90 of zirconium nitride for subsequent processing.

In some embodiments, the depositing step 120 is performed by PVD. In some embodiments, the first deposition step 110 is performed by a magnetron sputtering system. In other embodiments, PVD may be performed using HiPIMS, IBAD, or other deposition systems.

In some embodiments, the oxidizing step 130 oxidizes a portion of the intermediate layer 70 to form the outer layer 72. In some embodiments, the oxidation step 130 is performed as described in U.S. patent 6,447,550 and U.S. patent 5,324,009, each of which is expressly incorporated herein by reference in its entirety. In some embodiments, the oxidizing step 130 oxidizes at least a portion of the outer surface 80 of the intermediate layer 70. In some embodiments, the oxidizing step 130 oxidizes at least a portion of the zirconium nitride outer sub-layer 90 to oxidized zirconium, thereby forming the outer layer 72. In some embodiments, the oxidizing step 130 partially or completely oxidizes the exposed surface of the zirconium nitride outer sub-layer 90 into monoclinic oxidized zirconium. In some embodiments, the outer layer 72 comprises zirconium oxynitride. In some embodiments, the outer layer 72 comprises at least about 5% zirconium oxynitride.

In some embodiments, the oxidizing step 130 is performed by heating an environment that includes oxygen. In some embodiments, the environment is at a temperature of at least 500 ℃ or about 540 ℃. In some embodiments, the environment is at a temperature of about 500 ℃ to about 600 ℃. In an exemplary embodiment, the environment includes about 2.5% oxygen in argon. In some embodiments, the oxidizing step 130 is performed for about 5 hours.

In an alternative embodiment, process 100 includes a step (not shown) of depositing outer layer 72. The step of depositing the outer layer 72 is performed by PVD, which may be performed using a magnetron sputtering system. In other embodiments, PVD may be performed using HiPIMS, IBAD, or other deposition systems. In some embodiments, the step of depositing the outer layer 72 deposits a ceramic (e.g., zirconia) layer.

In some embodiments, the deposited zirconia forming the outer layer 72 comprises tetragonal, monoclinic, or cubic zirconia. In some embodiments, the deposited zirconia forming the outer layer 72 comprises tetragonal, monoclinic, or cubic zirconium oxynitrides.

In some embodiments, the coating 58 is configured to resist crushing when a force is applied. For example, the embodiment of fig. 19 illustrates the ability of the multilayer coating 58 to resist cracking and stop cracking when a force of about 9N is applied. Cracking occurs when the tensile strength of a material fails and begins to fracture. As shown in fig. 19, the niobium sub-layer stops the crack formed in the zirconium nitride sub-layer. Toughness and ductility were compared to fig. 20. As shown in fig. 20, the single layer of zirconium nitride produced much longer cracks than the multilayer coating in fig. 19 (i.e., sample 5 discussed below).

Examples

In the following examples, a series of single layer zirconium nitride (ZrN) coatings with niobium (Nb) tie layers were prepared and tested. In addition, various multilayer Nb/ZrN coatings of different architecture and thickness were prepared and tested. Table 1 provides information about each sample. Sample coatings 1 to 11 used Nb tie layers of about 140nm to 400nm to promote adhesion between the Ti-6Al-4V substrate and the coating. The coating is prepared by deposition using magnetron sputtering using enhancement of plasma by thermal ion emission (sample 5) using ions generated from the electrode as anode using the chamber wall (plasma enhanced magnetron sputtering), or by unbalanced magnetron sputtering to achieve the same goal of increasing the ionization rate of the plasma. Unbalanced magnetron deposition is performed on a flexcoat 1200 platform. Deposition parameters were selected from a series of experimental runs performed prior to preparing the test samples described below.

Table 1: description of the sample

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Monolayer (samples 1 to 4): the Ti-Al6-V4 ("Ti-6-4") coupons were polished to a roughness average (Ra) of less than 40nm and cleaned in preparation for use in thin film deposition. Four single layer ZrN coatings ranging in thickness from 2 μm to 10 μm were produced by unbalanced magnetron sputtering in a flexcoat 1200 coating station. The coating thickness was verified by examining the cross-section created by mounting and cross-sectioning or by Focused Ion Beam (FIB) and then examining in a Scanning Electron Microscope (SEM).

Multilayer (samples 5 to 8): the Ti-6-4 coupon was polished to less than 40nm Ra and cleaned in preparation for thin film deposition. A series of multilayer Nb/ZrN coatings were produced by unbalanced magnetron sputtering in a Flexicoat 1200 coating station. The thickness of the various seed layers within the intermediate layer is determined by examining the cross-section created by mounting and transecting or by FIB slicing, then examining in SEM. All multilayer coatings (i.e., samples 5 to 11) had 34 sublayers of Nb/ZrN, or were described below as 17 bilayers, where Nb represents 55% to 60% of the bilayer thickness. Sample 5, designated ML-nom, is a coating designed to have a potential nominal thickness, with each Nb/ZrN bilayer having a thickness of about 300nm, a ZrN outer layer thickness of about 2500nm, and a Nb tie layer thickness of about 400 nm. This coating is shown in cross section in fig. 16, wherein the layer thicknesses are summarized in table 2. By growing all layers by 20% (ml+20), shrinking all layers by 20% (ML-20), and shrinking all layers by 40% (ML-40) compared to ML-nom (sample 5), three additional Multilayer (ML) coatings were produced. Samples 5 to 8 are summarized in table 2.

Table 2: thickness and parameters of the multilayer coating (samples 5 to 8)

Multilayer gradient (samples 9 to 11): finally, a coating with gradient stiffness was prepared in a series of 3 multi-layer gradient coatings having the same number of bilayers (i.e. 17) as the non-gradient structure described above, but with Nb% in the first bilayer set to about 75% of bilayer thickness and then Nb% in the subsequent bilayer reduced by 5% so that bilayer 17 contained about 33% Nb. A potentially nominal gradient coating with 2400nm ZrN outer layer and 8738nm total thickness was produced and identified as MLG-Nom (i.e., sample 9) and shown in FIB cross section in fig. 17 and summarized in table 3. All layers were increased by 25% (MLG+25) and decreased by 25% in MLG-25, with the summarized thicknesses shown in tables 4 and 5.

Table 3: thickness and parameters of multilayer gradient coating MLG-Nom (sample 9)

Table 4: thickness and parameters of multilayer gradient coating MLG+25 (sample 10)

Table 5: thickness and parameters of multilayer gradient coating MLG-25 (sample 11)

Control (sample 12): samples 5 to 11 were compared with single layer coatings (samples 1 to 4) and commercially available coatings to demonstrate the advantages and improvements of the coatings.

And (5) scraping test. A scratch test was developed that reproduces the scratch observed on cobalt chrome (CoCr) femoral restorations. A diamond tip of radius 20 μm or 200 μm was applied with a load of 1 newton (N) to 6 newtons (N) or 3N to 36N, respectively, to reproduce the majority of scratches on the restorations and was applied to the single-layer and multi-layer samples described above and the commercial comparison.

The results shown in fig. 18 and 21, respectively, and listed in tables 6 and 7, show that the multilayer Nb/ZrN samples are better resistant to cracking and delamination than those produced with ZrN monolayers (samples 2 and 4), and to a similar extent as the commercially available comparison (sample 12) of similar thickness. Fig. 19 shows a cross section of the multilayer coating ML-Nom (sample 5) after scratch test, which shows how the ductile Nb layer stops cracking starting in the harder and weaker ZrN layer.

Table 6: results of scratch testing on various coating samples with increased force (graphically shown in fig. 18)。

Table 7: results of scratch testing on various samples with increased force (graphically shown in FIG. 21)。

While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative and not restrictive in character, it being understood that only the illustrative 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.

The various features of the methods, apparatus and systems described herein provide a number of advantages to the present disclosure. It should be noted that alternative embodiments of the methods, apparatus and systems of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the above-described methods, apparatus, and systems that may 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.

Claims (16)

1. An orthopedic knee implant, comprising:

a femoral component configured to be coupled to a distal end of a femur of a patient, the femoral component comprising (i) a base comprising a titanium alloy having (a) a condyle surface curved in a longitudinal plane and (b) a bone-facing surface positioned opposite the condyle surface; and

(ii) A coating disposed on the condyle surface, the coating comprising (a) a bonding layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, or combinations thereof, (b) an outer ceramic layer,

characterized in that the coating further comprises (c) a plurality of alternating sublayers positioned between an inner layer and the outer ceramic layer and interconnecting the bonding layer and the outer ceramic layer,

wherein (i) the plurality of alternating sublayers is configured to resist crack propagation from the outer ceramic layer, the plurality of alternating sublayers comprises a plurality of metallic sublayers and a plurality of ceramic sublayers that are harder than the metallic sublayers, and (ii) the outer ceramic layer forms an outer articular surface of the femoral component and is shaped to contact a concave proximal surface of a tibial bearing.

2. The implant of claim 1, wherein the plurality of alternating sublayers comprises at least eight sublayers of alternating zirconium nitride and niobium nitride sublayers.

3. The implant of claim 2, wherein each zirconium nitride sub-layer of the alternating sub-layers has a thickness of 5nm to 200 nm.

4. The implant of claim 3, wherein the plurality of alternating sublayers have a thickness of 3 μιη to 8 μιη.

5. The implant of claim 1, wherein the outer ceramic layer comprises at least 90% monoclinic oxidized zirconium.

6. The implant of claim 5, wherein the outer ceramic layer has a thickness of 100nm to 5 μιη.

7. The implant of claim 6, wherein at least one sub-layer of the plurality of alternating sub-layers comprises at least 95% zirconium nitride.

8. The implant of claim 1, wherein at least one sub-layer of the plurality of alternating sub-layers has a thickness of 5nm to 500 nm.

9. The implant of claim 8, wherein at least one sub-layer of the plurality of alternating sub-layers comprises at least 95% niobium nitride.

10. The implant of claim 1, wherein the bonding layer comprises at least 90% zirconium.

11. The implant of claim 10, wherein the bonding layer has a thickness of 50nm to 2 μιη.

12. The implant of claim 1, wherein the femoral component comprises a bone engaging layer disposed on the bone-facing surface.

13. The implant of claim 12, wherein the bone engaging layer is porous.

14. The implant of claim 1, wherein the plurality of alternating sublayers includes an inner sublayer and an outer sublayer.

15. The implant of claim 14, wherein the inner and outer sublayers have the same composition.

16. The implant of claim 14, wherein the plurality of alternating sublayers includes an intermediate sublayer having a different composition than the inner sublayer, the outer sublayer, or both.