Coated Implant and Method for Producing the Same

Abstract

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

Description

Technical Field

[0001] (Claims of Priority) This application claims priority to U.S. Provisional Patent Application No. 62 / 978,534, filed on February 19, 2020; U.S. Provisional Patent Application No. 62 / 978,537, filed on February 19, 2020; and U.S. Provisional Patent Application No. 63 / 010,300, filed on April 15, 2020, the contents of each of which are incorporated herein by reference.

[0002] (Cross - References to Related Applications) Cross - references are made to International Application No. AA2021 / XXXXXX (Attorney Docket No. 265280 - 333800, DSP6176USPCT1), a co - pending international application entitled "COATED IMPLANT AND METHOD OF MAKING THE SAME" and to U.S. Patent Application No. ## / , (Attorney Docket No. 265280 - 333150; Johnson & Johnson File No. DSP6174USNP1) entitled "COATED IMPLANT AND METHOD OF MAKING THE SAME", each of which is incorporated herein by reference.

[0003] (Field of the Invention) The present disclosure generally relates to implantable orthopedic prostheses, and more particularly, to femoral components of implantable orthopedic prostheses.

Background Art

[0004] Arthroplasty is a well-known surgical procedure in which a diseased and / or damaged living joint is replaced by an artificial joint. A typical artificial knee joint includes a patellar prosthesis 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 the surgically prepared distal end of the patient's femur. The tibial tray is designed to be attached to the surgically prepared proximal end of the patient's tibia.

[0005] The femoral component and the tibial tray can be made of a biocompatible material such as a cobalt-chromium metal alloy. The tibial bearing component disposed between the femoral component and the tibial tray can be formed from a plastic material such as polyethylene.

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, cobalt alloys tend to be expensive, and thus there is a need for components made from non-cobalt metal materials and methods for manufacturing them. For example, there is a need for a femoral component of an artificial knee joint made of a non-cobalt metal material and a method for manufacturing the same.

Means for Solving the Problems

[0007] 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 the distal end of a patient's femur. The femoral component comprises a substrate including a titanium alloy. Exemplarily, the substrate has a spherical surface curved in the sagittal plane and a bone-facing surface positioned on the opposite side of the spherical surface. An articular layer (also referred to as a "coating") is disposed on the spherical surface. The coating includes a first layer (also referred to as a "bonding layer" or an "inner layer") including niobium, zirconium, titanium, tantalum, platinum, molybdenum, or a combination thereof. The coating also includes a second layer (also referred to as an "intermediate layer") including several alternating sublayers. The coating further includes a third layer (also referred to as an "outer layer") including zirconium oxide, niobium oxide, zirconium oxynitride, niobium oxynitride, titanium, or a combination thereof. The first layer extends between and interconnects the second layer and the spherical 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.

[0008] In some embodiments, the second layer may include at least eight sublayers of alternating zirconium nitride sublayers and niobium nitride sublayers. In some embodiments, each zirconium nitride sublayer of the alternating sublayers may have a thickness of from about 0.5 nm to about 200 nm. In some embodiments, the second layer may have a thickness of from about 3 μm to about 6 μm.

[0009] In some embodiments, the third layer may include at least about 90% monoclinic zirconium oxide. In some embodiments, the third layer may have a thickness of from about 100 nm to about 5 μm.

[0010] In some embodiments, at least one sublayer of the second layer may include at least about 95% zirconium nitride.

[0011] In some embodiments, at least one sublayer of the second layer can have a thickness of from about 5 nm to about 500 nm. In some embodiments, at least one sublayer of the second layer can comprise at least about 95% niobium nitride.

[0012] In some embodiments, the first layer can comprise at least about 90% zirconium. In some embodiments, the first layer can have a thickness of from about 50 nm to about 1 μm.

[0013] Exemplarily, the femoral component can include a bone-engaging layer disposed on the bone-facing surface. In some embodiments, the bone-engaging layer can be porous.

[0014] In some embodiments, the second layer can include an inner sublayer and an outer sublayer. In some embodiments, the inner sublayer and the outer sublayer can have the same composition. In some embodiments, the second layer can include an intermediate sublayer having a composition different from that of the inner sublayer, the outer sublayer, or both.

[0015] In some embodiments, the third layer can be titanium zirconium nitride. Additionally, in some embodiments, the atomic percent of zirconium in the third layer can be from 50 At% to 80 At%. In some embodiments, the atomic percent of zirconium in the third layer can be from 30 At% to 85 At%.

[0016] In some embodiments, some alternating sublayers can include some titanium zirconium nitride sublayers and some metal layers. In some embodiments, the atomic percent of zirconium in the plurality of alternating sublayers is from 30 At% to 85 At%. Additionally, in some embodiments, the atomic percent of zirconium-titanium alloy in the plurality of alternating sublayers is from 30 At% to 85 At%.

[0017] 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 combinations thereof on a granular surface of a substrate. The substrate comprises titanium. The granular surface is curved in the sagittal plane. In some embodiments, the process includes depositing a second layer comprising several alternating sub-layers.

[0018] In some embodiments, the process may include oxidizing a portion of the second layer to form a third layer comprising zirconium oxide.

[0019] In some embodiments, the alternating sub-layers may include sub-layers of zirconium nitride and sub-layers of niobium. In some embodiments, depositing several alternating sub-layers to form the second layer may include: (a) forming a sub-layer of zirconium nitride on the first layer; (b) forming a sub-layer of niobium on the sub-layer of zirconium nitride; and (c) repeating steps (a) and (b) to form the second layer.

[0020] 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 include zirconium oxide, niobium oxide, oxynitride of zirconium, oxynitride of niobium, or combinations thereof.

[0021] Additional embodiments are contemplated.

[0022] Claim 1. An orthopedic knee implant comprising a femoral component configured to be coupled to the distal end of a patient's femur, the femoral component comprising: (i) a substrate comprising a titanium alloy having (a) a condylar surface curved in the sagittal plane and (b) a bone opposing surface positioned on the opposite side of the condylar surface; and (ii) a coating disposed on the condylar 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 sub-layers; and (c) a third layer comprising (i) a tetragonal zirconium oxide layer and (ii) a monoclinic zirconium oxide layer, wherein (i) the first layer extends between and interconnects the second layer and the condylar surface, (ii) the second layer extends between and interconnects the first layer and the third layer, and (iii) the third layer forms the outer surface of the coating. An orthopedic knee implant. Claim 2. The orthopedic knee implant of claim 1, wherein the second layer further comprises a sub-layer comprising zirconium. Claim 3. The orthopedic knee implant of claim 2, wherein each of the zirconium sub-layers comprises at least about 70% tetragonal zirconium. Claim 4. The orthopedic knee implant of any one of claims 1-3, wherein the second layer comprises 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. Claim 5. The orthopedic knee implant of any one of claims 1-4, wherein the tetragonal zirconium oxide layer extends between and interconnects the monoclinic zirconium oxide layer and the second layer. Claim 6. The orthopedic knee implant of any one of claims 1-5, wherein the third layer has a thickness of from about 2 μm to about 5 μm. Claim 7. The orthopedic knee implant of any one of claims 1-6, wherein the tetragonal zirconium oxide layer has a thickness of from about 200 nm to about 3 μm. Claim 8. The orthopedic knee implant of any one of claims 1-7, wherein the monoclinic zirconium oxide layer has a thickness of from about 200 nm to about 3 μm. Item 9. The orthopedic knee implant according to any one of Items 1 to 8, wherein the second layer has a thickness of about 3 μm to about 6 μm. Item 10. The orthopedic knee implant according to any one of Items 1 to 9, wherein the second layer includes zirconium nitride sub-layers each having a thickness of about 10 nm to about 200 nm. Item 11. The orthopedic knee implant according to any one of Items 4 to 10, wherein each zirconium nitride sub-layer contains at least about 95% zirconium nitride. Item 12. The orthopedic knee implant according to any one of Items 1 to 11, wherein the second layer includes niobium nitride sub-layers each having a thickness of about 10 nm to about 200 nm. Item 13. The orthopedic knee implant according to any one of Items 4 to 12, wherein each niobium nitride sub-layer contains at least about 95% niobium nitride. Item 14. The orthopedic knee implant according to any one of Items 1 to 13, wherein the second layer includes zirconium sub-layers each having a thickness of about 10 nm to about 200 nm. Item 15. The orthopedic knee implant according to any one of Items 4 to 14, wherein each zirconium sub-layer contains at least about 95% zirconium. Item 16. The orthopedic knee implant according to any one of Items 1 to 14, wherein the first layer contains at least about 90% zirconium. Item 17. The orthopedic knee implant according to any one of Items 1 to 16, wherein the first layer has a thickness of about 50 nm to about 1 μm, or about 1 μm to about 3 μm. Item 18. The orthopedic knee implant according to any one of Items 1 to 17, wherein the femoral component includes a bone-engaging layer disposed on the bone-facing surface. Item 19. The orthopedic knee implant according to Item 18, wherein the bone-engaging layer is porous. Item 20. A process for forming a femoral component of a knee implant for orthopaedic use, the process comprising: i) depositing a first layer containing zirconium on the granular surface of a titanium substrate, the granular surface being curved in the sagittal plane; ii) depositing several alternating sub-layers to form a second layer; and iii) depositing a third sub-layer containing zirconium nitride on the second layer. Item 21. The process according to Item 20, wherein the second deposition step comprises depositing a zirconium sub-layer. Item 22. A knee implant for orthopaedic use, comprising a femoral component configured to be connected to the distal end of a patient's femur, the femoral component comprising: (i) a substrate containing a titanium alloy having: (a) a granular surface curved in the sagittal plane; and (b) a bone-facing surface located on the opposite side of the granular surface; and (ii) a coating disposed on the granular surface, the coating comprising: (a) a first layer containing niobium, zirconium, titanium, tantalum, platinum, molybdenum, their alloys, or combinations thereof; (b) a second layer containing several alternating sub-layers; and (c) a third layer containing zirconium oxide, wherein: (i) the first layer extends between and interconnects the second layer and the granular surface; (ii) the second layer extends between and interconnects the first layer and the third layer; and (iii) the third layer forms the outer surface of the coating. Item 23. The implant according to Item 22, wherein the second layer comprises at least eight alternating sub-layers of zirconium nitride and niobium nitride. Item 24. The implant according to Item 23, wherein each zirconium nitride sub-layer of the alternating sub-layers has a thickness of about 5 nm to about 200 nm. Item 25. The implant according to any one of Items 22 to 24, wherein the second layer has a thickness of about 3 μm to about 6 μm. Item 26. The implant according to any one of Items 22 to 25, wherein the third layer contains at least about 90% monoclinic zirconium oxide. Item 27. The implant according to any one of Items 22 to 26, wherein the third layer has a thickness of about 100 nm to about 5 μm. Item 28. The implant according to any one of Items 22 to 27, wherein at least one sublayer of the second layer contains at least about 95% zirconium nitride. Item 29. The implant according to any one of Items 22 to 28, wherein at least one sublayer of the second layer has a thickness of about 5 nm to about 500 nm. Item 30. The implant according to any one of Items 22 to 29, wherein at least one sublayer of the second layer contains at least about 95% niobium nitride. Item 31. The implant according to any one of Items 22 to 30, wherein the first layer contains at least about 90% zirconium. Item 32. The implant according to any one of Items 22 to 31, wherein the first layer has a thickness of about 50 nm to about 1 μm. Item 33. The implant according to any one of Items 22 to 32, wherein the femoral component includes a bone-engaging layer disposed on the bone-facing surface. Item 34. The implant according to Item 33, wherein the bone-engaging layer is porous. Item 35. The implant according to any one of Items 22 to 34, wherein the second layer includes an inner sublayer and an outer sublayer. Item 36. The implant according to Item 35, wherein the inner sublayer and the outer sublayer have the same composition. Item 37. The implant according to any one of Items 35 to 36, wherein the second layer includes an intermediate sublayer having a composition different from that of the inner sublayer, the outer sublayer, or both. Item 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 the granulated surface of a substrate comprising titanium, the granulated surface being curved in the sagittal plane, and depositing a second layer comprising several alternating sublayers. Item 39. The process according to item 38, comprising oxidizing a part of the second layer to form the third layer. Item 40. The process according to any one of items 38 to 39, wherein the alternating sublayers include a sublayer of zirconium nitride and a sublayer of niobium nitride. Item 41. The process according to any one of items 38 to 40, comprising depositing a third layer on the outer surface of the second layer. Item 42. The process according to item 41, wherein the third layer includes zirconium nitride, titanium zirconium nitride, zirconium oxide, niobium oxide, zirconium oxynitride, niobium oxynitride, or a combination thereof. Item 43. An orthopedic knee implant comprising a femoral component configured to be coupled to the distal end of a patient's femur, the femoral component comprising: (i) a substrate comprising a titanium alloy having (a) a trochlear surface curved in the sagittal plane and (b) a bone opposing surface positioned on the opposite side of the trochlear surface; and (ii) a coating disposed on the trochlear 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 several alternating sublayers grouped into two or three layers; and (c) a third layer comprising zirconium oxide, wherein (i) the first layer extends between and interconnects the second layer and the trochlear surface, (ii) the second layer extends between and interconnects the first layer and the third layer, and (iii) the third layer forms the outer surface of the coating. Item 44. The implant according to item 43, wherein the second layer includes at least 12 two - layer sublayers, and each sublayer within the two - layer sublayer has a similar thickness. Item 45. The implant according to item 44, wherein each sublayer has a thickness of about 5 nm to about 200 nm. Item 46. The implant according to any one of items 43 to 45, wherein the second layer has a thickness of about 3 μm to about 8 μm. Item 47. The implant according to any one of items 43 to 46, wherein the third layer includes at least about 90% monoclinic zirconium oxide. Item 48. The implant according to any one of Items 43 to 47, wherein the third layer has a thickness of about 100 nm to about 5 μm. Item 49. The implant according to Item 43, wherein the second layer includes at least eight three - layer structures, and each sub - layer within the three - layer structure has a similar thickness. Item 50. The implant according to Item 49, wherein each sub - layer has a thickness of about 5 nm to about 500 nm. Item 51. The implant according to Item 43, wherein the second layer includes at least twelve two - layer structures, each sub - layer within the two - layer structure has a different thickness, and all the two - layer structures have a uniform thickness. Item 52. The implant according to Item 43, wherein the second layer includes at least eight three - layer structures, each sub - layer within the three - layer structure has a different thickness, and all the three - layer structures have a uniform thickness. Item 53. The implant according to any one of Items 43 to 52, wherein the first layer has a thickness of about 50 nm to about 1 μm or 100 nm to 2 μm. Item 54. The implant according to any one of Items 43 to 53, wherein the femoral component includes a bone - engaging layer disposed on the bone - facing surface. Item 55. The implant according to Item 54, wherein the bone - engaging layer is porous. Item 56. Each two - layer structure includes a first sub - layer and a second sub - layer. The first sub - layer has a thickness that decreases between 1% and 20% in each subsequent two - layer structure, and the second sub - layer has a thickness that increases between 1% and 20% in each subsequent two - layer structure. The implant according to Item 51. Item 57. The implant according to Item 56, wherein the first sub - layer constitutes at least 55% of the second layer. Item 58. The implant according to any one of Items 43 to 57, wherein the second layer includes a metal sublayer selected from the group consisting of niobium, zirconium, titanium, tantalum, platinum, molybdenum, their alloys, and combinations thereof, a ceramic sublayer including niobium, zirconium, titanium, tantalum, molybdenum, platinum, or combinations thereof, and a third layer selected from the group consisting of zirconium oxide, niobium oxide, zirconium oxynitride, niobium oxynitride, titanium nitride, titanium nitride, and combinations thereof. Item 59. The implant according to Item 43, wherein the third layer includes titanium zirconium nitride. Item 60. A process for forming a femoral component of an orthopedic knee implant, the process comprising depositing a first layer including niobium, zirconium, titanium, tantalum, platinum, molybdenum, or combinations thereof on a granular surface of a substrate including titanium, the granular surface being curved in the sagittal plane, and depositing several alternating sublayers to form a second layer. Item 61. The process according to Item 60, comprising oxidizing a part of the second layer to form a third layer including zirconium oxide. Item 62. The process according to Item 61, wherein the alternating sublayers include a sublayer of zirconium nitride and a sublayer of niobium nitride. Item 63. The process according to any one of Items 60 to 62, comprising depositing a third layer on the outer surface of the second layer. Item 64. The process according to Item 63, wherein the third layer includes zirconium nitride, titanium zirconium nitride, zirconium oxide, niobium oxide, zirconium oxynitride, niobium oxynitride, or combinations thereof. Item 65. An orthopedic knee implant comprising a femoral component configured to be connected to the distal end of a patient's femur, the femoral component comprising: (i) a substrate comprising a titanium alloy having (a) a condylar surface curved in the sagittal plane and (b) a bone opposing surface positioned on the opposite side of the condylar surface; and (ii) a coating disposed on the condylar 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 sub-layers positioned between and interconnecting the first layer and the outer ceramic third layer, wherein (i) the plurality of alternating sub-layers are configured to resist crack propagation from the outer ceramic third layer, the plurality of alternating sub-layers comprising some metal sub-layers and some ceramic sub-layers harder than the metal sub-layers; and (ii) the outer ceramic third layer forms the outer articular surface of the femoral component and is shaped to contact the concave proximal surface of the tibial bearing. An orthopedic knee implant. Item 66. The orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 or 52), and 65, wherein the first sub-layer and the second sub-layer form a two-layer comprising niobium and zirconium nitride, and the third layer comprises zirconium nitride. Item 67. The orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 or 52), and 65, wherein the first sub-layer and the second sub-layer form a two-layer comprising niobium and zirconium nitride, and the third layer comprises zirconium titanium nitride. Item 68. The orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 or 52), and 65, wherein the first sub-layer and the second sub-layer form a two-layer comprising zirconium nitride and zirconium, and the third layer comprises zirconium nitride. Item 69. An orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 and 52), and 65, wherein the first sublayer and the second sublayer form a two-layer structure containing zirconium nitride and zirconium, and the third layer contains titanium zirconium nitride. Item 70. An orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 and 52), and 65, wherein the first sublayer and the second sublayer form a two-layer structure containing zirconium titanium and titanium zirconium nitride, and the third layer contains titanium zirconium nitride. Item 71. An orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 and 52), and 65 to 70, wherein the third layer contains zirconium nitride. Item 72. An orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 and 52), and 65 to 70, wherein the third layer contains titanium zirconium nitride. Item 73. An orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 and 52), and 65 to 70, wherein the intermediate layer contains a plurality of alternating titanium zirconium nitride sublayers and zirconium titanium alloy metal sublayers. Item 74. An orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 and 52), and 65 to 70, wherein the intermediate layer contains a plurality of alternating zirconium nitride sublayers and zirconium titanium alloy sublayers. Item 75. An orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59 (excluding 49 and 52), and 65 to 70, wherein the third layer contains ceramic. Item 76. An orthopedic knee implant according to any one of Items 1 to 19, 22 to 37, 43 to 59, and 65 to 75, wherein a plurality of alternating sublayers are grouped by two or three layers. Item 77. The orthopedic knee implant according to item 76, wherein each of the two or three layers has a uniform thickness with respect to other grouped sub-layers in the intermediate layer, but the individual thicknesses of the sub-layers within the group vary. Item 78. The orthopedic knee implant according to any one of items 1 to 19, 22 to 37, 43 to 59, and 65 to 77, wherein the third layer is titanium zirconium nitride. Item 79. The orthopedic knee implant according to item 78, wherein the atomic percentage of zirconium in the third layer is 50 At% to 80 At%. Item 80. The orthopedic knee implant according to item 78, wherein the atomic percentage of zirconium in the third layer is 30 At% to 85 At%. Item 81. The orthopedic knee implant according to items 1 to 19, 22 to 37, 43 to 59, and 65 to 80, wherein the plurality of alternating sub-layers includes some titanium zirconium nitride sub-layers and some metal layers. Item 82. The orthopedic knee implant according to item 81, wherein the atomic percentage of zirconium in the plurality of alternating sub-layers is 30 At% to 85 At%. Item 83. The orthopedic knee implant according to item 81, wherein the atomic percentage of zirconium-titanium alloy in the plurality of alternating sub-layers is 30 At% to 85 At%.

Brief Description of the Drawings

[0023] For a detailed description, specifically refer to the following drawings.

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DETAILED DESCRIPTION OF THE INVENTION

[0024] The concepts of the present disclosure are subject to various modifications and alternative forms, but specific exemplary embodiments thereof are shown in the drawings and described in detail herein. However, it is not intended to limit the concepts of the present disclosure to the specific forms disclosed, and on the contrary, it is to be understood that the present invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended "claims".

[0025] Terms representing anatomical references such as front, back, inner, outer, upper, lower, etc. may be used throughout this specification with respect to the orthopedic implant or orthopedic prosthesis described herein and with reference to the patient's living anatomical structure. Such terms have meanings well understood in both the study of anatomy and the field of orthopedic surgery. The use of such anatomical reference terms in the description and "claims" is intended to be consistent with their well-understood meanings unless otherwise specified.

[0026] Referring now to FIG. 1, in one embodiment, an orthopedic artificial knee joint 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 that is configured to be coupled to the tibial tray 16. In the exemplary embodiment of FIG. 1, the tibial bearing 14 is embodied as a rotary 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 be embodied as a fixed tibial bearing that can be restricted or inhibited from rotating relative to the tibial tray 16.

[0027] The tibial tray 16 is configured to be fixed to the surgically prepared proximal end of a patient's tibia (not shown). The tibial tray 16 can be fixed to the patient's tibia via the use of bone cement or other attachment methods. The tibial tray 16 includes a platform 18 having an upper surface 20 and a bottom surface 22. Exemplarily, the upper surface 20 is generally planar. The tibial tray 16 also includes a stem 24 extending downwardly from the bottom surface 22 of the platform 18. A cavity or hole 26 is defined within the upper surface 20 of the platform 18 and extends downwardly into the stem 24. The hole 26 is formed to receive a complementary stem 36 of the tibial bearing 14, as will be described in more detail below.

[0028] As described above, the tibial bearing 14 is configured to be coupled to 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 an exemplary embodiment where the tibial bearing 14 is embodied as a rotational 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 within the hole 26 of the tibial tray 16. In use, the tibial bearing 14 is configured to rotate about an axis defined by the stem 36 relative to the tibial tray 16. In embodiments where the tibial bearing 14 is embodied as a fixed tibial bearing, the bearing 14 may or may not include the stem 36 and / or may include other devices or features for fixing the tibial bearing 14 to the tibial tray 16 in a non-rotating configuration.

[0029] The upper bearing surface 32 of the tibial bearing 14 includes an inner bearing surface 42 and an outer bearing surface 44. The inner bearing surface 42 and the outer bearing surface 44 are configured to receive or otherwise contact corresponding inner condyles 52 and outer condyles 54 of the femoral component 12, as will be described in more detail below. Thus, each of the bearing surfaces 42, 44 has a concave contour.

[0030] The femoral component 12 is configured to be coupled to a surgically prepared surface of the distal end of a patient's femur (not shown). The femoral component 12 can be secured to the patient's femur via the use of a bone cementing method or other attachment method. The femoral component 12 includes a pair of inner condyles 52 and outer condyles 54. The condyles 52, 54 are spaced apart so as to define an intercondylar notch 56 therebetween. In use, the condyles 52, 54 are configured to articulate on corresponding bearing surfaces 42, 44 of the platform 30 of the tibial bearing 14, replacing the native condyles of the patient's femur.

[0031] The exemplary orthopedic knee implant 10 of FIG. 1 (which may be referred to as an "implant") is embodied as a posterior cruciate ligament retaining knee implant. That is, the femoral component 12 is embodied as a posterior cruciate ligament retaining femoral component, and the tibial bearing 14 is embodied as a posterior cruciate ligament retaining tibial bearing 14. However, in other embodiments, the orthopedic knee implant 10 can be embodied as a posterior cruciate ligament sacrificing knee implant.

[0032] Referring now to FIGS. 1 and 2, the femoral component 12 is configured to articulate on the tibial bearing 14 in use. Each condyle 52, 54 of the femoral component 12 is convexly curved in the sagittal plane and includes an outer articular surface 50 configured to face respective bearing surfaces 42, 44 of the tibial bearing 14.

[0033] As shown in FIG. 2, the femur component 12 includes a substrate 60 and a coating 58. Exemplarily, the coating 58 is disposed on the substrate 60 and configured to interact with the tibial bearing 14. In some embodiments, the femur component 12 includes an osseous engagement layer 62 located on the opposite side of the coating 58, and the substrate 60 is located between the coating 58 and the osseous engagement layer 62. The osseous engagement layer 62 is configured to interact with the surgically prepared femur of the patient.

[0034] The substrate 60 includes a spheroid surface 66 and a bone-facing surface 64, as shown in FIG. 2. The spheroid surface 66 is curved in the sagittal plane and configured such that the coating 58 is located on the substrate 60. The bone-facing surface 64 is positioned on the opposite side of the spheroid surface 66 and is arranged to face the surgically prepared distal end of the patient's femur. In some embodiments, the bone-facing surface 64 directly contacts the surgically prepared femur. In some embodiments, the osseous engagement layer 62 is bonded to the bone-facing surface 64 of the substrate 60.

[0035] FIGS. 1 and 2 show a cementless embodiment of the femur component 12 in which the osseous engagement layer 62 is configured to be implanted between the femur component 12 and the surgically prepared distal end of the patient's femur in the absence of cement. In some embodiments, the osseous engagement layer 62 includes titanium. It should be understood that the osseous engagement layer 62 can be a separately applied coating such as Porocoat® Porous Coating commercially available from DePuy Synthes of Warsaw, Indiana.

[0036] In some embodiments, the bone-engaging layer 62 can 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 geometric structures, which in an exemplary embodiment is a rhombic trigonal trapezohedron. It should be understood that such geometric structures can vary to suit the needs of a given design. Further, it should be understood that the bone-engaging layer 62 can be formed from any other alternative shape suitable for meeting the needs of a given design.

[0037] In some embodiments, the bone-engaging layer 62 is formed from a metal powder. Exemplarily, the metal powder can include, but is not limited to, titanium, titanium alloys, stainless steel, cobalt-chromium alloys, tantalum, niobium, or combinations thereof. The bone-engaging layer 62 has a porosity suitable for promoting ingrowth of bone into the bone-engaging layer 62 of the femoral component 12 when implanted onto a surgically prepared surface of the distal end of a patient's femur.

[0038] In the exemplary embodiments described herein, the bone-engaging layer 62 is fabricated additively directly on the bone-facing surface 64 of the femoral component 12. In such embodiments, the two structures, namely the femoral component 12 and the bone-engaging layer 62, can be fabricated simultaneously during a common additive manufacturing process. For example, the two structures can be fabricated simultaneously in a single 3D printing operation that results in a common monolithic metal component that includes both structures. Alternatively, the bone-engaging layer 62 can be fabricated as a separate component that is secured to the bone-facing surface 64 of the femoral component 12.

[0039] In an alternative embodiment, the femoral component 12 is configured to be attached using cement to the surgically prepared distal end of the patient's femur. In some embodiments, the femoral component 12 includes a cement reservoir (not shown) disposed on the bone-facing surface 64. In some embodiments, the bone adhesive is disposed on the bone-facing surface 64. In some embodiments, the bone adhesive includes bone cement. In some embodiments, the bone-facing surface 64 is configured to receive the bone adhesive.

[0040] In some embodiments, the substrate 60 is a metal. In some embodiments, the substrate 60 includes a metal alloy. In some embodiments, the substrate 60 includes a titanium alloy. In some embodiments, the substrate 60 includes titanium and vanadium. In some embodiments, the substrate 60 includes titanium, aluminum, and vanadium. In some embodiments, the substrate 60 includes Ti-6Al-4V. In some embodiments, the substrate 60 consists essentially of Ti-6Al-4V.

[0041] Referring now to FIGS. 2 and 3, the coating 58 is disposed on the articular surface 66. The coating 58 is located on the opposite side of the bone-facing surface 64, and the substrate 60 is located between the coating 58 and the bone engagement layer 62. The coating 58 is configured to interact with the bearing surfaces 42, 44 and articulate with the tibial bearing 14.

[0042] The coating 58 has several layers 68, 70, 72. The layers 68, 70, 72 can each be constructed of a material having mechanical properties (e.g., enhanced wear resistance, chipping resistance, delamination resistance, adjustable stiffness, ductility, corrosion resistance, and oxidation resistance) that are desirable for use in constructing the coating 58.

[0043] In some embodiments, the coating 58 cooperates with the substrate 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 agglomerate chipping 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 cracking.

[0044] Referring now to FIG. 3, the coating 58 includes an inner or bonding 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 a material having favorable mechanical properties for use in the construction of the coating 58. For example, the intermediate layer 70 is constructed of a material that provides stiffness and ductility to disperse force loading, prevent cracking, and improve adhesion of the coating 58 to the substrate 60. The bonding layer 68, on the other hand, is constructed of a material having favorable mechanical properties for use in securing the coating 58 to the substrate 60.

[0045] As used herein, the term "layer" is not intended to be limited to a thickness of a material positioned adjacent to another similar-sized "thickness" of material, but rather is intended to include a number of structures, configurations, and constructs of the material. For example, the term "layer" can include a portion, region, or other structure of a material positioned adjacent to another portion, region, or structure of a different material. For example, the interface between the intermediate layer 70 and the outer layer 72 is shown as being uniform in FIG. 3, but 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, a "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 by oxidizing an outer portion of the intermediate layer 70. In alternative embodiments, a "layer" is formed by providing additional material to an existing surface. For example, in some embodiments, the bonding layer 68 is formed by depositing material onto the particulate surface 66.

[0046] As shown in FIG. 3, the bonding layer 68 is disposed on the particulate surface 66. The outer layer 72 is disposed to form the outer articular surface 50 of the coating 58 and thus the femoral component 12. The intermediate layer 70 extends between and interconnects the bonding layer 68 and the outer layer 72. In some embodiments, the coating 58 can be further processed (as shown in FIG. 11) such that the exposed surface of the intermediate layer 70 forms the outer articular surface 50 and does not include the outer layer 72.

[0047] The bonding layer 68 extends between and interconnects the intermediate layer 70 and the particulate surface 66. The inner layer 68 includes an inner surface 74 and an outer surface 76. The inner surface 74 is positioned between the outer surface 76 and the particulate surface 66. The outer surface 76 of the inner layer 68 is positioned between the inner surface 74 of the inner layer 68 and the intermediate layer 70. In some embodiments, the inner layer 68 is configured to reduce delamination of the coating 58 from the femoral component 12.

[0048] The bonding layer 68 can have a specific thickness measured from the particle surface 66. In some embodiments, the bonding layer 68 can be present with a thickness ranging from the nanoscale to the microscale. In some embodiments, the bonding layer 68 has a thickness of about 0.5 nm to about 10 nm, about 0.5 nm to about 3 nm, or about 5 nm to about 10 nm. In some embodiments, the bonding 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 200 nm 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 bonding layer 68 has a thickness of about 200 nm, about 220 nm, about 240 nm, about 260 nm, about 280 nm, about 300 nm, about 320 nm, about 340 nm, about 360 nm, about 38 nm, about 400 nm, about 420 nm, about 440 nm, about 460 nm, about 480 nm, or about 500 nm.

[0049] The bonding layer 68 can include a metal, an alloy, or another suitable material to provide favorable mechanical properties for use in fixing the coating 58 to the substrate 60. For example, the composition of the bonding layer 68 can be selected to minimize agglomeration chipping of the coating 58 during manufacture and use. In an exemplary embodiment, the bonding layer 68 includes niobium, zirconium, titanium, tantalum, molybdenum, platinum, hafnium, combinations thereof, or any other suitable metal. In some embodiments, the bonding layer 68 includes zirconium. In some embodiments, the bonding layer 68 includes at least about 90% zirconium. In some embodiments, the bonding layer 68 includes at least about 95% zirconium. In some embodiments, the bonding layer 68 includes at least about 90% niobium, titanium, tantalum, molybdenum, platinum, or combinations thereof. In some embodiments, the bonding layer 68 includes at least about 95% niobium, zirconium, titanium, tantalum, molybdenum, platinum, hafnium, or combinations thereof.

[0050] As described above, the intermediate layer 70 extends between and interconnects the bonding layer 68 and the outer layer 72. The 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.

[0051] In some embodiments, the intermediate layer 70 has an overall thickness of from about 3 μm to about 7 μm. In some embodiments, the intermediate layer 70 has an overall thickness of from about 3 μm to about 8 μm. In some embodiments, the intermediate layer 70 has an overall thickness of from about 5 nm to about 5 μm. In some embodiments, the intermediate layer 70 has an overall thickness of from about 1.5 μm to about 2.0 μm. In some embodiments, the intermediate layer 70 has an overall thickness of at least about 50 nm, at least about 100 nm, at least about 200 nm, 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.

[0052] The intermediate layer 70 can be formed of a plurality of sub-layers. The order and composition of the sub-layers 86, 88, 90 are configured to disperse the load and prevent cracks that may occur. In an exemplary embodiment, the intermediate layer 70 is formed of an inner sub-layer 86, an intermediate sub-layer 88, and an outer sub-layer 90. In some exemplary embodiments, some or all of the sub-layers 86, 88, 90 are repeated such that the intermediate layer 70 can include one of the sub-layers two or more times.

[0053] Sub-layers 86, 88, 90 may include a metal, an alloy, a ceramic, or other suitable material, as described herein. Exemplarily, various combinations of sub-layers 86, 88, or 90 provide fracture toughness and corrosion resistance. For example, each of sub-layers 86, 88, and 90 may include niobium, zirconium, titanium, tantalum, hafnium, molybdenum, platinum, combinations thereof, or any other suitable metal including their alloys. Each of sub-layers 86, 88, and 90 may include a ceramic including niobium, zirconium, titanium, tantalum, molybdenum, platinum, combinations thereof, or any other suitable ceramic. Exemplarily, the ceramic may include a metal and a nitride, carbide, oxide, or combinations thereof. For example, the ceramic may include zirconium nitride, zirconium titanium nitride, zirconium oxide, or niobium nitride.

[0054] In some embodiments, some alternating sub-layers include some zirconium titanium nitride sub-layers and some metal layers. In some embodiments, the atomic percentage of zirconium in the plurality of alternating sub-layers is from 30 At% to 85 At%. In some embodiments, the atomic percentage of zirconium in the plurality of alternating sub-layers is about 30 At%, about 35 At%, about 40 At%, about 45 At%, about 50 At%, about 55 At%, about 60 At%, about 65 At%, about 70 At%, about 75 At%, about 80 At%, or about 85%. Additionally, in some embodiments, the atomic percentage of zirconium-titanium alloy in the plurality of alternating sub-layers is from 30 At% to 85 At%. In some embodiments, the atomic percentage of zirconium-titanium alloy in the plurality of alternating sub-layers is about 30 At%, about 35 At%, about 40 At%, about 45 At%, about 50 At%, about 55 At%, about 60 At%, about 65 At%, about 70 At%, about 75 At%, about 80 At%, or about 85%.

[0055] In an exemplary embodiment, some or all of the sub-layers 86, 88, 90 may participate in a superlattice with an adjacent layer or sub-layer. In some embodiments, each of the sub-layers 86, 88, 90 has a thickness of about 0.5 nm to about 10 nm, about 5 nm to about 10 nm, or about 0.5 nm to about 3 nm. In some embodiments, each of the sub-layers 86, 88, 90 has a thickness of about 5 nm to about 500 nm.

[0056] The intermediate layer 70 may include two different sub-layers that can be alternately stacked. For example, referring to FIG. 5, the intermediate layer 70 may include an inner sub-layer 86, an intermediate sub-layer 88, and an outer sub-layer 90. The compositions of the inner sub-layer 86, the intermediate sub-layer 88, and the outer sub-layer 90 may be the same or different. For example, the intermediate layer 70 may have an arrangement of two sub-layers having -A-B- or (-A-B-), for example, including the inner sub-layer 86 and the intermediate sub-layer 88, where 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 sub-layer 86 is A and the intermediate sub-layer 88 is B. For example, in the case of a repetition of two sub-layers such as A-B-A-B-A-B, each A-B may be referred to as a "bilayer". Thus, a bilayer is a grouping of two sub-layers. In some embodiments, the composition of layer A includes 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 sub-layers is selected such that the intermediate layer 70 reaches 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. n Alternatively, the intermediate layer 70 may have an arrangement of two repetitions of sub-layers, for example, an inner sub-layer 86 and an intermediate sub-layer 88, and an outer sub-layer 90, as shown in FIGS. 3 and 5. In some examples, the intermediate layer 70 has an arrangement A-(B-A) including repetitions of the inner sub-layer 86 and the intermediate sub-layer 88.

[0057] Alternatively, the intermediate layer 70 may have an arrangement of two repetitions of sub-layers, for example, an inner sub-layer 86 and an intermediate sub-layer 88, and an outer sub-layer 90, as shown in FIGS. 3 and 5. In some examples, the intermediate layer 70 has an arrangement A-(B-A) including repetitions of the inner sub-layer 86 and the intermediate sub-layer 88. n-C-, where each of A and B is a different composition, n is at least 1, at least 2, at least 4, or at least 10, and where C is the outer sublayer 90 and has the same composition as one of the inner sublayer 86 or the intermediate sublayer 88. In some embodiments, the composition of layer A includes 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 outer sublayer 90 includes zirconium nitride. In some embodiments, the intermediate layer 70 includes a repeating sequence of i) a sublayer of zirconium nitride and ii) a sublayer of niobium, tetragonal and / or monoclinic zirconium, tantalum, titanium hafnium, niobium nitride, tantalum nitride, or hafnium nitride, and iii) is capped by the outer sublayer 90 of zirconium nitride. In some embodiments, some of the alternating sublayers are selected such that the intermediate layer 70 reaches a thickness of, for example, up to about 5 μm.

[0058] Alternatively, the intermediate layer 70 may have an arrangement of three repeats of sublayers, for example, the sequence of the inner sublayer 86, the intermediate sublayer 88, and the outer sublayer 90. In some examples, the intermediate layer 70 has the composition -(A - B - C) n-comprising a repeating sequence of an inner sublayer 86, an intermediate sublayer 88, and an outer sublayer 90, where 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, the inner sublayer 86 is A, the intermediate sublayer 88 is B, and the outer sublayer 90 is C. For example, if there are repetitions of three sublayers such as A-B-C-A-B-C-A-B-C, each A-B-C can be referred to as a "three-layer". Thus, a three-layer is a grouping of three sublayers. The formula shows the sequence of A-B-C, but it should be noted that any permutation in the order of the sublayers, such as A-C-B, B-C-A, etc., is contemplated. It should be further noted that the intermediate layer 70 can include an arrangement of a plurality of sublayers, such as an arrangement of -A-B-C-B-C-A-, etc. It should be further noted that the intermediate layer 70 can include an arrangement of a plurality of sublayers, such as an arrangement of -A-B-A-B-A-B-A-C-A-C-A-C-, etc. It should be further noted that the intermediate layer 70 can include an arrangement of a plurality of sublayers, such as an arrangement of -A-B-A-C-A-B-A-C-A-B-A-C-, etc. For example, referring to FIG. 13, the intermediate layer 70 has a first arrangement of two sublayers having n -A-B- or (-A-B-), where 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 a second arrangement of two sublayers having n -A-C- or (-A-C-), where each of A and C is a different composition, and n is at least 1, at least 2, at least 4, or at least 10, and may include. Exemplarily, any one of the compositions A, B, or C can include niobium nitride, tantalum nitride, hafnium nitride, zirconium nitride, niobium, tetragonal and / or monoclinic zirconium, tantalum, titanium, or hafnium.

[0059] In some embodiments, the intermediate layer 70 includes a zirconium nitride inner sublayer 86, a niobium nitride intermediate sublayer 88, and a zirconium nitride outer sublayer 90. In some embodiments, the intermediate layer 70 includes at least one zirconium nitride inner sublayer 86 and at least one niobium nitride intermediate sublayer 88. In some embodiments, the intermediate layer 70 includes several alternating sublayers of zirconium nitride and niobium nitride. In some embodiments, the intermediate layer 70 includes at least four alternating sublayers of the zirconium nitride inner sublayer 86 and the niobium nitride intermediate sublayer 88. In an exemplary embodiment, the zirconium nitride outer sublayer 90 is formed on the outermost niobium nitride intermediate sublayer 88. FIG. 3 shows a single sublayer of the zirconium nitride inner sublayer 86 and a single sublayer of the niobium nitride intermediate sublayer 88, but it will be understood that any number of alternating sublayers are contemplated.

[0060] In some embodiments, the inner sublayer 86 has a thickness of from about 5 nm to about 500 nm. In some embodiments, the inner sublayer 86 has a thickness of at least about 0.05 nm, at least about 1 nm, at least about 5 nm, at least about 10 nm, at least about 50 nm, at least about 100 nm, at least about 150 nm, at least about 200 nm, at least about 250 nm, at least about 300 nm, at least about 350 nm, at least about 400 nm, at least about 450 nm, at least about 500 nm, or at least about 550 nm. In some embodiments, the inner sublayer 86 has a thickness of from about 1 nm to about 200 nm, or from about 5 nm to about 100 nm. In some embodiments, the sublayer 86 has a thickness of about 30 nm, about 40 nm, about 50 nm, about 60 nm, about 70 nm, about 80 nm, about 90 nm, about 100 nm, about 110 nm, about 120 nm, about 130 nm, about 140 nm, about 150 nm, about 160 nm, about 170 nm, about 180 nm, about 190 nm, about 200 nm, about 210 nm, or about 220 nm. In some embodiments, the sublayer 86 has a thickness of about 65 nm, about 95 nm, about 115 nm, about 125 nm, or about 205 nm.

[0061] In some embodiments, the inner sublayer 86 comprises at least about 90% zirconium nitride. In some embodiments, the inner sublayer 86 comprises at least about 95% zirconium nitride.

[0062] In some embodiments, the intermediate sublayer 88 has a thickness of about 5 nm to about 500 nm. In some embodiments, the intermediate sublayer 88 has a thickness of at least about 1 nm, at least about 5 nm, at least about 10 nm, at least about 50 nm, at least about 100 nm, at least about 150 nm, or at least about 200 nm, at least about 250 nm, at least about 300 nm, at least about 350 nm, at least about 400 nm, at least about 450 nm, at least about 500 nm, or at least about 550 nm. In some embodiments, the sublayer 88 has a thickness of about 30 nm, about 40 nm, about 50 nm, about 60 nm, about 70 nm, about 80 nm, about 90 nm, about 100 nm, about 110 nm, about 120 nm, about 130 nm, about 140 nm, about 150 nm, about 160 nm, about 170 nm, about 180 nm, about 190 nm, about 200 nm, about 210 nm, or about 220 nm. In some embodiments, the sublayer 88 has a thickness of about 65 nm, about 95 nm, about 115 nm, about 125 nm, or about 205 nm.

[0063] 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.

[0064] In some embodiments, the outer sublayer 90 has a thickness of from about 1 μm to about 5 μm. In some embodiments, the outer sublayer 90 has a thickness of from about 2 μm to about 3 μm. In some embodiments, the 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 and the coating 58 of the femoral component 12.

[0065] 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.

[0066] 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. Exemplarily, 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.

[0067] In some embodiments, the outer layer 72 can be formed by depositing the outer layer 72 or by thermal growth due to oxidation of a portion of the 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 50 nm, at least about 100 nm, at least about 150 nm, at least about 200 nm, or at least about 250 nm. When the outer layer 72 is deposited, the outer layer 72 can 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 can have a thickness of about 100 nm to about 200 nm. In some embodiments, the outer layer 72 has a thickness of about 1000 nm, about 1500 nm, about 1800 nm, about 1900 nm, about 2000 nm, about 2400 nm, about 2500 nm, about 2800 nm, about 3000 nm, about 3100 nm, or about 3500 nm.

[0068] 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 can be oxidized to thermally grow the outer layer 72. Exemplarily, thermal growth can occur by oxygen inserting into a portion of the intermediate layer 70, such as the lattice of the outer portion, to form an oxide. In some embodiments, the outer layer 72 includes a ceramic. In an exemplary embodiment, the ceramic of the outer layer 72 is an oxide of the composition of the intermediate sublayer 70. In some embodiments, the outer layer 72 includes an oxide of an alloy of niobium and zirconium. In some embodiments, the outer layer 72 includes zirconium oxide. In some embodiments, the outer layer 72 includes niobium oxide. In some embodiments, the outer layer 72 includes zirconium oxide and niobium oxide. In some embodiments, the outer layer 72 includes monoclinic zirconium oxide. In some embodiments, the outer layer 72 includes at least about 90% zirconium oxide. In some embodiments, the outer layer 72 includes at least about 90% monoclinic zirconium oxide. In some embodiments, the outer layer 72 includes monoclinic and / or tetragonal zirconium oxynitride. In some embodiments, the outer layer 72 includes at least about 5% zirconium oxynitride. In some embodiments, the outer layer 72 includes at least about 2% tetragonal zirconium oxide. In some embodiments, the outer layer 72 includes at least about 2% cubic zirconium oxide. In some embodiments, the outer layer 72 includes a ceramic containing titanium. In an exemplary aspect, the outer layer 72 includes titanium zirconium nitride. In some embodiments, the outer layer 72 includes a metal oxide and titanium.

[0069] 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 zirconium oxide. The deposited zirconium oxide of the outer layer 72 can be tetragonal zirconium oxide or monoclinic zirconium oxide. In an exemplary embodiment, when monoclinic zirconium oxide is deposited, a layer of tetragonal zirconium oxide is formed between the monoclinic zirconium oxide and the intermediate sublayer 70. In some exemplary embodiments, the outer layer 72 is formed by increasing the oxygen concentration while depositing the outermost sublayer of the intermediate layer 70 such that the outer layer 72 is an oxide of the outermost sublayer of the intermediate layer 70. For example, if the outermost sublayer of the intermediate layer 70 (e.g., the outer sublayer 90) is zirconium nitride, the outer layer 72 can be formed by increasing the oxygen concentration of the deposit to form zirconium oxynitride, sometimes referred to as oxynitride zirconium. In some embodiments, the outer layer 72 can comprise zirconium oxynitride and niobium oxynitride.

[0070] In some embodiments, the third layer can be titanium zirconium nitride. Additionally, in some embodiments, the atomic percent of zirconium in the third layer can be from 50 At% to 80 At%. In some embodiments, the atomic percent of zirconium in the third layer can be about 50 At%, about 55 At%, about 60 At%, about 65 At%, about 70 At%, about 75 At%, or about 80 At%. In some embodiments, the atomic percent of zirconium in the third layer can be from 30 At% to 85 At%. In some embodiments, the atomic percent of zirconium in the third layer can be about 30 At%, about 35%, about 40%, about 45 At%, about 50 At%, about 55 At%, about 60 At%, about 65 At%, about 70 At%, about 75 At%, about 80 At%, or about 85%.

[0071] In some embodiments, the bonding layer 68 comprises zirconium, the intermediate layer 70 comprises at least one zirconium nitride sublayer 86 and at least one niobium nitride sublayer 88, and the outer layer 72 comprises zirconium oxide.

[0072] Referring now to FIG. 4, the femoral component 12 of the orthopedic artificial knee joint 10 can be formed through process 100. In some embodiments, process 100 includes a first deposition step 110 of depositing a bonding layer 68, a second deposition step 120 of depositing an intermediate layer 70, and an oxidation step 130. In an exemplary embodiment, process 100 includes a step of preparing a substrate 60 for the deposition step 110. In some embodiments, process 100 includes a finishing step after the oxidation step 130, such as polishing.

[0073] Referring now to FIGS. 6-9, an exemplary schematic embodiment of the femoral component 12 is shown. Exemplarily, A represents a sublayer, and optionally, as shown in FIGS. 6-9, it is shown as a repeated stacking of sublayers using zirconium nitride.

[0074] Referring now to FIGS. 10-15, an exemplary schematic embodiment of the femoral component 12 is shown. In each example, A represents a part of the substrate 60, B represents a layer or sublayer containing niobium, C represents a layer or sublayer containing zirconium nitride, one B and one C together form a two-layer structure, and D represents a layer containing niobium nitride. In some embodiments, the outer layer 72 of C represents a layer containing Ti-doped zirconium nitride. As exemplarily shown in FIGS. 10-15, the bonding layer 68 contains niobium. In some embodiments, the bonding layer 68 may contain niobium, zirconium, titanium, tantalum, platinum, molybdenum, their alloys, or combinations thereof.

[0075] As shown in the embodiment of FIG. 10, the intermediate layer 70 includes several alternating sub-layers (C and B), with 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 single layer D can be further processed (e.g., oxidized) to form the outer joint surface 50. In the embodiment of FIG. 12, the intermediate layer 70 includes several alternating sub-layers (C and B) and (C and D), with n = 24, and the outer layer 72 is a single layer C. In the embodiment of FIG. 13, the intermediate layer 70 includes several alternating sub-layers (C and D) and (B and C), with n = 24, and the outer layer 72 is a single layer C. In the embodiment of FIG. 14, the intermediate layer 70 includes several alternating sub-layers (C-D-C-B), with n = 24, and the outer layer 72 is a single layer C. In the embodiment of FIG. 15, the intermediate layer 70 includes several alternating sub-layers (C and D), with n = 24, and the outer layer 72 is a single layer C.

[0076] The intermediate layer 70 can be a single layer, such as a layer containing niobium nitride in FIG. 11. Alternatively, the intermediate layer 70 can include a repeated stacking of layers. In some embodiments, the intermediate layer 70 includes a repeated stacking of a sub-layer containing zirconium nitride and a sub-layer containing niobium, as exemplarily shown in FIG. 10. In some embodiments, the intermediate layer 70 includes a first repeated stacking of a sub-layer 86 containing zirconium nitride and a sub-layer 88 containing niobium, and a second repeated stacking of a sub-layer 86 containing zirconium nitride and a sub-layer 88 containing niobium nitride, as exemplarily shown in FIGS. 12 and 13. In some embodiments, the intermediate layer 70 includes a repeated stacking of a sub-layer 86 containing zirconium nitride, a sub-layer 88 containing niobium nitride, a sub-layer 86 containing zirconium nitride, and a sub-layer 90 containing niobium, as exemplarily shown in FIG. 14. In some embodiments, the intermediate layer 70 includes a repeated stacking of a sub-layer 88 containing zirconium nitride and a sub-layer 86 containing niobium nitride, as exemplarily shown in FIG. 15.

[0077] In the exemplary embodiments of FIGS. 10-15, the bonding layer 68 has a thickness of about 0.5 μm or about 5 μm. Except for the sublayer 90 farthest from the substrate, each sublayer 86 and 88 of the intermediate layer 70 has a thickness of about 125 nm. Exemplarily, each of the embodiments in FIGS. 10-15 includes an outer sublayer 90 of zirconium nitride having a thickness of about 3 μm. This outer layer can optionally be further processed to form the outer layer 72.

[0078] Alternatively, the intermediate layer 70 can include a repeating sublayer arrangement where the repeats have a uniform thickness across the span of the intermediate layer 70, but the thickness of the individual sublayers varies. Referring to FIG. 17, sublayers 86 and 88 are stacked in a repeating arrangement having a total thickness that is uniform in the intermediate layer 70, but the thickness of each individual sublayer 86 or sublayer 88 is varied. For example, the percentage of the thickness of sublayer 86 can gradually decrease, and the percentage of the thickness of sublayer 88 can gradually increase for each subsequent arrangement. In one embodiment, sublayer 86 can be 75% of the total thickness of the first arrangement, and sublayer 88 can be 25% of the total thickness. Then, in the second arrangement, sublayer 86 can constitute 70%, and sublayer 88 can constitute 30%. Subsequently, the third arrangement can include 65% sublayer 86 and 35% sublayer 88. In this way, sublayers 86 and 88 are gradually varied in steps across the span of the intermediate layer 70. In some embodiments, the presence of sublayer 86 in the arrangement decreases by 5% in each subsequent arrangement, and the presence of sublayer 88 in the arrangement increases by 5% across the span of the intermediate layer 70. Thus, each arrangement of sublayers 86 and 88 maintains a uniform thickness across the span of the intermediate layer 70. Further exemplary embodiments are provided in Tables 3, 4, and 5. In some embodiments, the abundance of sublayer 86 in the arrangement decreases 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 arrangement. Conversely, in some embodiments, the abundance of sublayer 88 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 25% in each subsequent arrangement.

[0079] In some embodiments, the first deposition step 110 deposits a material to form a bonding layer 68 on the particulate 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 can be performed using HiPIMS, IBAD, or other deposition systems.

[0080] In some embodiments, the second deposition step 120 forms an intermediate layer 70 on the outer surface 76 of the bonding layer 68. In some embodiments, the second deposition step 120 is being performed by PVD. In some embodiments, the deposition step 120 is performed by a magnetron sputtering system.

[0081] In some embodiments, the second deposition step 120 includes depositing an inner sublayer 86. Exemplarily, the inner sublayer 86 is deposited on the bonding layer 68 by the second deposition step 120.

[0082] In some embodiments, the second deposition step 120 includes depositing an intermediate sublayer 88 on the inner sublayer 86. In an exemplary embodiment, the second deposition step 120 includes repeating the steps of depositing the inner sublayer 86 and the intermediate sublayer 88 until a desired number of sublayers is achieved. Then, an outer sublayer 90 can be deposited on the outermost deposited sublayer (e.g., the inner sublayer 86 or the intermediate sublayer 88).

[0083] In some embodiments, the second deposition step 120 includes depositing an outer sublayer 90 on the intermediate sublayer 88. In an exemplary embodiment, the second deposition step 120 includes repeating the steps of depositing the inner sublayer 86, the intermediate sublayer 88, and the outer sublayer 90 until a desired number of sublayers is achieved. Optionally, the final outer sublayer 90 is deposited on the outermost sublayer (e.g., the inner sublayer 86, the intermediate sublayer 88, or the outer sublayer 90).

[0084] In some embodiments, the second deposition step 120 includes depositing a zirconium nitride inner sublayer 86 over the bonding layer 68, depositing a niobium nitride intermediate sublayer 88 over the zirconium nitride inner sublayer 86, and depositing a zirconium nitride outer sublayer 90 over the niobium nitride intermediate sublayer 88.

[0085] In some embodiments, the second deposition step 120 is performed to produce several alternating sublayers of the zirconium nitride inner sublayer 86 and the niobium nitride intermediate sublayer 88. In some embodiments, the steps of depositing the zirconium nitride inner sublayer 86 and the niobium nitride intermediate sublayer 88 are repeated until a desired thickness is obtained. In some embodiments, the thickness is up to 6 μm.

[0086] In some embodiments, the second deposition step 120 deposits an outer sublayer 90 of zirconium nitride for subsequent processing.

[0087] 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 can be performed using HiPIMS, IBAD, or other deposition systems.

[0088] In some embodiments, oxidation step 130 oxidizes a portion of intermediate layer 70 to form outer layer 72. In some embodiments, oxidation step 130 is performed as described in U.S. Patent No. 6,447,550 and U.S. Patent No. 5,324,009, each of which is hereby expressly incorporated by reference in its entirety. In some embodiments, oxidation step 130 oxidizes at least a portion of outer surface 80 of intermediate layer 70. In some embodiments, oxidation step 130 oxidizes at least a portion of zirconium nitride outer sublayer 90 to zirconium oxide to form outer layer 72. In some embodiments, oxidation step 130 partially or completely oxidizes the exposed surface of zirconium nitride outer sublayer 90 to monoclinic zirconium oxide. In some embodiments, outer layer 72 comprises zirconium oxynitride. In some embodiments, outer layer 72 comprises at least about 5% zirconium oxynitride.

[0089] In some embodiments, oxidation step 130 is performed by heating an environment containing oxygen. In some embodiments, the environment is at a temperature of at least 500°C or about 540°C. In some embodiments, the environment is at a temperature of about 500°C to about 600°C. In an exemplary embodiment, the environment contains about 2.5% oxygen in argon. In some embodiments, oxidation step 130 is performed for about 5 hours.

[0090] In an alternative embodiment, process 100 includes a step of depositing an outer layer 72 (not shown). The step of depositing outer layer 72 is performed by PVD, which can be performed using a magnetron sputtering system. In other embodiments, PVD can be performed using HiPIMS, IBAD, or other deposition systems. In some embodiments, the step of depositing outer layer 72 deposits a ceramic layer, such as zirconium oxide.

[0091] In some embodiments, the deposited zirconium oxide forming the outer layer 72 comprises tetragonal, monoclinic, or cubic zirconium oxide. In some embodiments, the deposited zirconium oxide forming the outer layer 72 comprises tetragonal, monoclinic, or cubic zirconium oxynitride.

[0092] In some embodiments, the coating 58 is configured to resist chipping when a force is applied. For example, the embodiment of FIG. 19 shows that when a force of about 9 N is applied, the multilayer coating 58 exhibits the ability to resist chipping and prevent cracking. Cracking occurs when the tensile strength of the material decreases and fracture begins. As shown in FIG. 19, the niobium sublayer prevents cracks formed in the zirconium nitride sublayer. Compare the toughness and ductility with FIG. 20. As illustrated in FIG. 20, a single layer of zirconium nitride developed much longer cracks compared to the multilayer coating in FIG. 19 (i.e., sample 5 discussed below).

Examples

[0093] In the following examples, a series of single-layer zirconium nitride (ZrN) coatings with a niobium (Nb) bonding layer were produced and tested. Additionally, various multilayer Nb / ZrN coatings with different structures and thicknesses were produced and tested. Table 1 provides information regarding each sample. Samples 1-11 used a Nb bonding layer of approximately 140 nm to 400 nm to promote adhesion between the Ti-6Al-4V substrate and the coating. The coatings were prepared by using magnetron sputtering (plasma-enhanced magnetron sputtering) to enrich the plasma with ions generated by thermionic emission from an electrode using the chamber wall as an anode (sample 5), or by deposition via unbalanced magnetron sputtering to achieve the same purpose of increasing the ionization rate of the plasma. The unbalanced magnetron deposition was performed on a Flexicoat 1200 platform. The deposition parameters were selected from a series of experiments performed prior to producing the test samples described below.

[0094]

Table 1

[0095] Single layer (Samples 1 - 4): The Ti - Al6 - V4 ("Ti - 6 - 4") coupons were polished to a roughness average (Ra) of less than 40 nm and cleaned in preparation for thin film deposition. Four single layer ZrN coatings with thicknesses in the range of 2 μm to 10 μm were produced by unbalanced magnetron sputtering on a Flexicoat 1200 coating platform. The coating thickness was verified by inspection of cross - sections produced either by mounting and sectioning, or by inspection with a focused ion beam (FIB) followed by a scanning electron microscope (SEM).

[0096] Multilayers (Samples 5 - 8): The Ti-6-4 coupons were polished to an Ra of less than 40 nm and cleaned in preparation for thin film deposition. A series of multilayer Nb / ZrN coatings were produced by balanced magnetron sputtering on a Flexicoat 1200 coating platform. The thicknesses of the various sub-layers within the intermediate layer were determined by inspection of cross-sections produced either by mounting and sectioning or by FIB sectioning followed by SEM inspection. All multilayer coatings (i.e., Samples 5 - 11) had 34 sub-layers of Nb / ZrN (or described below as 17 bilayers), with Nb representing 55 - 60% of the bilayer thickness. Sample 5, designated ML-nom, was a coating designed to have a potential nominal thickness with each Nb / ZrN bilayer having a thickness of approximately 300 nm, an outer ZrN layer thickness of approximately 2500 nm, and a Nb bonding layer thickness of approximately 400 nm. This coating is shown in cross-section in Figure 16, and the layer thicknesses are summarized in Table 2. Three additional multilayer (ML) coatings were produced 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). Samples 5 - 8 are summarized in Table 2.

[0097]

Table 2

[0098] Multilayer Gradients (Samples 9 - 11): Finally, coatings with graded stiffness were prepared with a series of three multilayer graded coatings having the same bilayer number (i.e., 17) as the non-graded structures above, where the %Nb in the first bilayer was set at approximately 75% of the bilayer thickness, and then the thickness of each subsequent bilayer was decreased by 5% such that bilayer 17 contained approximately 33% Nb. A potential nominal graded coating with a 2400 nm ZrN outer layer and a total thickness of 8738 nm was produced, identified as MLG-Nom (i.e., target sample 9), shown in the FIB cross-section of Figure 17, and summarized in Table 3. All layers were increased by 25% (MLG + 25) and decreased by 25% (MLG - 25). The summary thicknesses are shown in Tables 4 and 5.

[0099]

Table 3

[0100]

Table 4

[0101]

Table 5

[0102] Control (Sample 12): To demonstrate the advantages and improvements of the coatings described, Samples 5 - 11 were compared to single-layer coatings (Samples 1 - 4) and commercially available coatings.

[0103] Scratch Testing. A scratch test was developed to reproduce the scratches observed on cobalt-chromium (CoCr) femoral prostheses. To reproduce most of the scratches on the prostheses, a diamond tip having either a radius of 20 μm or 200 μm and loaded with a load of 1 - 6 Newtons (N) or 3 - 36 N, respectively, was applied to the single-layer and multilayer samples described above, as well as to commercially available comparators.

[0104] As shown in FIGS. 18 and 21 and tabulated in Tables 6 and 7, the results indicate that the multilayer Nb / ZrN samples resisted chipping and delamination better than those produced with single layers of ZrN (Samples 2 and 4) and to a similar extent as a commercially available comparator of similar thickness (Sample 12). FIG. 19 shows a cross-sectional view of the multilayer coating ML-Nom (Sample 5) after a scratch test, which illustrates how the ductile Nb layer arrests cracks that originate in the harder and more brittle ZrN layer.

[0105]

Table 6

[0106]

Table 7

[0107] Although the present disclosure has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered as illustrative and not restrictive in nature, and have shown and described only exemplary embodiments, and it is understood that all changes and modifications included within the spirit of the present disclosure are desired to be protected.

[0108] The present disclosure has a plurality of advantages based on various features of the methods, apparatuses, and systems described herein. It should be noted that alternative embodiments of the methods, apparatuses, and systems of the present disclosure do not include all of the features described, but still enjoy at least some of the advantages of such features. Those skilled in the art can readily implement alone methods, apparatuses, and systems that incorporate one or more of the features of the present invention and are within the spirit and scope of the present disclosure as defined in the appended "claims".

[0109] 〔Embodiments〕 (1) An orthopedic knee implant, A femoral component configured to be connected to the distal end of a patient's femur, said femoral component comprising: (i) a substrate comprising a titanium alloy having a condylar surface curved in the sagittal plane and a bone-facing surface located on the opposite side of said condylar surface; (ii) a coating disposed on said condylar surface, said coating comprising (a) a bonding layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, or combinations thereof, (b) an outer ceramic layer, and (c) a plurality of alternating sub-layers positioned between and interconnecting said inner layer and said outer ceramic layer; (i) said plurality of alternating sub-layers being configured to resist crack propagation from said outer ceramic layer, said plurality of alternating sub-layers comprising some metal sub-layers and some ceramic sub-layers harder than said metal sub-layers, and (ii) said outer ceramic layer forming the outer articular surface of said femoral component and being shaped to contact the concave proximal surface of a tibial bearing, an orthopedic knee implant. (2) The implant according to embodiment 1, wherein the second layer comprises at least eight sub-layers of alternating zirconium nitride sub-layers and niobium nitride sub-layers. (3) The implant according to embodiment 2, wherein each zirconium nitride sub-layer of said alternating sub-layers has a thickness of about 5 nm to about 200 nm. (4) The implant according to embodiment 3, wherein said second layer has a thickness of about 3 μm to about 8 μm. (5) The implant according to embodiment 1, wherein the third layer comprises at least about 90% monoclinic zirconium oxide.

[0110] (6) The implant according to embodiment 5, wherein said third layer has a thickness of about 100 nm to about 5 μm. (7) The implant according to embodiment 6, wherein at least one sub-layer of said second layer comprises at least about 95% zirconium nitride. (8) The implant according to embodiment 1, wherein at least one sublayer of the second layer has a thickness of about 5 nm to about 500 nm. (9) The implant according to embodiment 8, wherein at least one sublayer of the second layer comprises at least about 95% niobium nitride. (10) The implant according to embodiment 1, wherein the first layer comprises at least about 90% zirconium.

[0111] (11) The implant according to embodiment 10, wherein the first layer has a thickness of about 50 nm to about 2 μm. (12) The implant according to embodiment 1, wherein the femoral component comprises a bone-engaging layer disposed on the bone-facing surface. (13) The implant according to embodiment 12, wherein the bone-engaging layer is porous. (14) The implant according to embodiment 1, wherein the second layer comprises an inner sublayer and an outer sublayer. (15) The implant according to embodiment 14, wherein the inner sublayer and the outer sublayer have the same composition.

[0112] (16) The implant according to embodiment 14, wherein the second layer comprises an intermediate sublayer having a composition different from that of the inner sublayer, the outer sublayer, or both. (17) 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 particulate surface of a substrate comprising titanium, the particulate surface being curved in the sagittal plane; depositing several alternating sublayers to form a second layer. (18) The process according to embodiment 17, further comprising oxidizing a portion of the second layer to form a third layer comprising zirconium oxide. (19) Depositing the several alternating sublayers to form the second layer is (a) Forming a sublayer of zirconium nitride on the first layer; (b) Forming a sublayer of niobium on the sublayer of zirconium nitride; (c) Repeating steps (a) and (b) to form the second layer, the process according to embodiment 17. (20) The process according to embodiment 17, including depositing a third layer on the outer surface of the second layer.

[0113] (21) The process according to embodiment 20, wherein the third layer comprises zirconium oxide, niobium oxide, oxynitride of zirconium, oxynitride of niobium, or a combination thereof.

Claims

1. An orthopedic knee implant, comprising a femoral component configured to be coupled to the distal end of a patient's femur, said femoral component comprising (i) a substrate comprising a titanium alloy having (a) a femoral surface curved in the sagittal plane and (b) a bone-facing surface positioned on the opposite side of said femoral surface, (ii) a coating disposed on said femoral surface, said coating comprising (a) a bonding layer comprising niobium, zirconium, titanium, tantalum, platinum, molybdenum, alloys thereof, or combinations thereof, (b) an outer ceramic layer, and (c) a plurality of alternating sublayers positioned between and interconnecting said bonding layer and said outer ceramic layer, (i) said plurality of alternating sublayers being configured to resist crack propagation from said outer ceramic layer, said plurality of alternating sublayers comprising alternating zirconium nitride sublayers and niobium sublayers, and (ii) said outer ceramic layer forming the outer articular surface of said femoral component and being shaped to contact the concave proximal surface of a tibial bearing. An orthopedic knee implant.

2. The implant according to claim 1, wherein said plurality of alternating sublayers comprise at least eight sublayers of alternating zirconium nitride sublayers and niobium sublayers.

3. The implant according to claim 2, wherein each zirconium nitride sublayer of said plurality of alternating sublayers has a thickness of from about 5 nm to about 200 nm.

4. The implant according to claim 3, wherein said plurality of alternating sublayers have a thickness of from about 3 μm to about 8 μm.

5. The implant according to claim 1, wherein the outer sublayer, which is the sublayer furthest from the substrate, comprises at least about 90% monoclinic zirconium oxide.

6. The implant according to claim 5, wherein said outer sublayer has a thickness of from about 100 nm to about 5 μm. **Claim 7**: The implant according to claim 6, wherein at least one of the plurality of alternating sub-layers comprises at least about 95% zirconium nitride. **Claim 8**: The implant according to claim 1, wherein at least one of the plurality of alternating sub-layers has a thickness of from about 5 nm to about 500 nm. **Claim 9** The implant according to claim 1, wherein the bonding layer comprises at least about 90% zirconium.

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