Orthopaedic knee joint prosthesis

Abstract

The invention relates to an orthopaedic knee joint prosthesis (2) having a metallic femoral implant part (4), a metallic tibial implant part (6) and a meniscus replacement part (8); according to the invention, it is proposed that the femoral implant part (4) and in particular also the tibial implant part (6) are manufactured additively by metallic 3D printing, that the femoral implant part (4) and / or the tibial implant part (6) have / has a three-dimensionally porous surface structure (30, 32) formed by the 3D printing, in surface regions (10, 16) facing the bone, to allow incorporation of the bone into the implant part (4, 6), and that the femoral implant part (4) and / or the tibial implant part (6) have / has at least in some areas a coating (52, 54) in surface regions (14, 20) not in contact with the bone and not in contact with the meniscus replacement part (8) but in contact with soft tissue, by means of which coating a surface roughness of these surface regions (14, 20) is reduced.

Description

[0001] Title: Orthopaedic knee joint prosthesis

[0002] Description

[0003] The invention relates to an orthopedic knee joint prosthesis with a metallic femoral implant part, with a metallic tibial implant part, and with a meniscus replacement part, which forms a sliding partner for the femoral implant part and is held on the tibial implant part, wherein the femoral implant part has surface areas facing the bone and in contact with the bone in the implanted state, wherein the femoral implant part has articulating condylar surface areas in sliding contact with the meniscus replacement part as a sliding partner in the implanted state, wherein the tibial implant part has surface areas facing the bone and in contact with the bone in the implanted state, wherein the tibial implant part has surface areas in contact with the meniscus replacement part in the implanted state,wherein the femoral implant part and the tibial implant part in the implanted state each have surface areas that are not in contact with the bone and not with the meniscus replacement part but are in soft tissue contact, wherein the femoral implant part has at least in some areas a hardening and wear-reducing, in particular multi-layered, coating on the articulating condylar surface areas that are in sliding contact with the sliding partner.

[0004] Such a knee joint prosthesis is previously known from EP 2 051 666 B1, which proposed forming articulating condylar surface regions of the femolar implant part that are in sliding contact with the meniscus replacement part, and also surface regions of the tibial implant part that are in contact with the meniscus replacement part, with a hardening and wear-reducing coating. This hardening and wear-reducing coating is in particular multi-layered and comprises in particular ceramic layers that prove to be particularly wear-resistant in sliding contact with corresponding articulation surfaces of the meniscus replacement part. They also prevent or reduce the release of metal ions from the interior of the femoral or tibial implant part as a result of the articulating sliding contact.Since then, attempts have only been made to optimize the wear resistance of surface areas of implant components subject to articulating sliding movements, including micromovements. A similar knee joint prosthesis is shown in US 8,642,112 B2. Here, too, a hardening and wear-reducing coating is applied to articulating surface areas. To form a three-dimensional porous surface structure facing and in contact with the bone, a separate porous layer is attached to the implant component. One embodiment involves a highly porous, open-cell biomaterial in the form of a reticulated carbon foam.

[0005] The object of the present invention is to achieve, on the one hand, optimal anchoring of the metallic implant material in the bone, starting from a knee joint prosthesis of the type mentioned at the beginning, and, on the other hand, to achieve unproblematic contact with surrounding soft tissue.

[0006] This object is achieved according to the invention, starting from a knee joint prosthesis of the type mentioned at the outset, in that the femoral implant part and in particular also the tibial implant part are manufactured additively by metallic 3D printing, that the femoral implant part and / or the tibial implant part have a three-dimensional porous surface structure formed by the metallic 3D printing in the surface areas facing the bone for the bone to grow into the implant part, and that the femoral implant part and / or the tibial implant part has, at least in some areas, a coating on the surface areas which are not in contact with the bone and not with the meniscus replacement part but are in soft tissue contact, by means of which coating a surface roughness of these surface areas is reduced.

[0007] It is therefore proposed, on the one hand, to provide a three-dimensionally porous surface structure by metallic 3D printing on the surface areas of the implant part in question that face the bone. On the other hand, it is proposed to provide a coating that reduces the surface roughness on the surface areas that are not in contact with the bone and not with the meniscus replacement part, but are in contact with the soft tissue. It has been found according to the invention that rough surfaces that are in contact with soft tissue can lead to increased cell death during movements relative to soft tissue. The present invention therefore proposes to specifically reduce the surface roughness on these surface areas of the implant parts that are in contact with soft tissue by applying a coating, so that there is less irritation to the surrounding soft tissue.The surface roughness is lower than that of the uncoated surface areas of the implant part under consideration produced by 3D printing, and also lower than that of the surface areas of the implant part under consideration facing the bone. As a result, an optimization of preferably all of the initially mentioned surface areas of the implant part under consideration is achieved with regard to their respective specific function in the implanted state of the prosthesis. For this purpose, the implant parts are advantageously manufactured in an additive manufacturing process using metallic 3D printing, whereby a certain surface roughness formed in this process can be smoothed by applying the coating.This coating of surface areas in contact with soft tissue reduces or even prevents the tendency for bone to grow onto the implant component, particularly in areas near the joint and at the transition to resection surfaces. Thus, undesirable heterotropic ossification can be prevented or reduced. This proves particularly advantageous in conjunction with implant components made of titanium or titanium alloy, since bone grows particularly well onto titanium.

[0008] The coating can advantageously prevent or reduce bacterial biofilm formation through the use of suitable materials, such as zirconium nitride (ZrN). Such biofilm formation is associated, for example, with infections that require revision surgery.

[0009] It may prove that the surface roughness of the surface areas not in contact with the bone or the meniscus replacement part, but in soft tissue contact and provided with the coating, is greater than or equal to the surface roughness of the articulating condylar surface areas in sliding contact and provided with the hardening and wear-reducing coating. Advantageously, the surface areas in soft tissue contact of the femoral implant part and / or the tibial implant part are designed to be as smooth as possible.It proves to be advantageous if the surface roughness of the surface areas not in contact with the bone and not with the meniscus replacement part but in contact with soft tissue and provided with the coating is at most 0.50 gm, in particular at most 0.40 gm, in particular at most 0.30 gm and in particular at least 0.04 gm, in particular at least 0.05 gm and in particular at least 0.10 gm, measured as Ra according to DIN / ISO 21920-3.

[0010] Various processes can be used to produce the coating that reduces surface roughness. It is advantageous if the coating on the surface areas that are not in contact with the bone or the meniscus replacement part, but are in contact with soft tissue, is produced using a PVD (Physical Vapor Deposition) process. This allows a very uniform and thin coating to be produced in a process-stable manner. In particular, it is advantageous if the coating has a coating thickness of 3.5 - 6.0 μm, which can be measured and determined in accordance with DIN / ISO 26423. Ceramic materials such as zirconium nitride (ZrN), chromium nitride (CrN) or chromium carbonitride (CrCN) are suitable for the coating, which can preferably be multi-layered.The coating can be bonded to the implant part via an adhesion-promoting layer, particularly one based on cobalt-chromium or titanium.

[0011] In an advantageous embodiment of the knee joint prosthesis according to the invention, it is provided that at least the tibial implant part has a three-dimensionally porous surface structure in the surface areas facing the bone for the bone to grow into the implant part, and that the tibial implant part has, at least in some areas, a coating on the surface areas not in contact with the bone and not with the meniscus replacement part but which are in contact with the soft tissue, by means of which coating the surface roughness of these surface areas is reduced. On the one hand, this allows a secure anchoring of the tibial implant part in the bone to be achieved, and on the other hand, the surrounding soft tissue in the area of ​​the tibial implant part is less irritated due to the smooth design of the surface in contact with the soft tissue.

[0012] The following explains the hardening and wear-reducing coating of the articulating surface areas in sliding contact with the meniscus replacement part. It proves advantageous if the hardening and wear-reducing, particularly multi-layered, coating of the articulating condylar surface areas in sliding contact comprises a ceramic surface, particularly made of or based on zirconium nitride (ZrN).

[0013] Furthermore, it proves to be advantageous if the hardening and wear-reducing coating of the articulating condylar surface areas in sliding contact is designed in several layers and is connected to the implant part via an adhesion-promoting layer, in particular based on titanium.

[0014] Furthermore, it proves to be advantageous if the hardening and wear-reducing coating comprises layers based on chromium nitride (CrN) and / or based on chromium carbonitride (CrCN) and / or based on zirconium nitride (ZrN).

[0015] Furthermore, it proves to be advantageous if the hardening and wear-reducing coating has a top layer based on zirconium nitride (ZrN) and inner layers based on chromium nitride (CrN) or chromium carbonitride (CrCN), whereby several inner layers based on chromium nitride (CrN) and chromium carbonitride (CrCN) can alternate.

[0016] It is furthermore advantageous if not only the articulating condylar surface areas of the femoral implant part, but also the tibial implant part in surface areas in contact with the meniscus replacement part, has a hardening and wear-reducing, in particular multi-layered, coating of the type just described in order to reduce wear due to micromovements between the meniscus replacement part and a plateau of the tibial implant part.

[0017] In order to bond the coating that reduces the surface roughness in the soft tissue contact area, it is advantageous if the coating of the surface areas that are not in contact with the bone and not with the meniscus replacement part but are in soft tissue contact is bonded to the implant part via a titanium-based adhesion promoter layer.

[0018] It has been found according to the invention that it is possible and even advantageous if the coating of the surface areas not in contact with the bone and not with the meniscus replacement part but in contact with the soft tissue is the same coating as the hardening and wear-reducing coating of the articulating condylar surface areas in sliding contact.

[0019] It is conceivable that the coatings are bonded to the base material of the respective implant component via different bonding layers. For example, it would be conceivable that the bonding layer in the hardening and wear-reducing coating is cobalt-chromium-based or titanium-based, and that the bonding layer in the surface roughness-reducing coating in the soft tissue contact area is titanium-based. However, both coatings could also be bonded via the same titanium-based bonding layer.

[0020] It is also advantageous if the meniscus replacement part has a polymer-based sliding surface, particularly a polyethylene-based one, that is in contact with the articulating condylar surface areas of the femoral implant part. The meniscus replacement part can also be made entirely of polymer.

[0021] With regard to the production of the implant parts, it has proven to be advantageous that the metallic femoral implant part and the metallic tibial implant part are manufactured additively. Additive manufacturing in the form of metallic 3D printing is suitable for the production of complex and in particular delicate structures which would be difficult or impossible to produce using injection or casting technology. With regard to the present invention, however, additive manufacturing has proven to be advantageous in that it can be used to produce any desired closed and / or three-dimensionally porous structures, including surface structures. For example, in the case of an implant part, both a preferably essentially closed articulating surface region and a three-dimensionally porous surface region in contact with the bone can be produced in the same implant part.The three-dimensional porous surface area on the respective implant part can therefore be produced by additive manufacturing in the form of metallic 3D printing, without the need to add an additional porous layer to the implant part. In particular, it is conceivable that a respective implant part can be formed with a three-dimensional bar structure in the area of ​​bone contact, whereby the three-dimensional bar structure can extend inwards to any depth starting from the outer shell. In this way, however, deep penetration of the bone tissue into the implant part can be achieved, which enables a lasting firm fit of the implant part and thus of the prosthesis. A certain surface roughness inherent in 3D printing can then be reduced in the soft tissue contact area by applying the roughness-reducing coating.

[0022] It proves particularly advantageous if the metallic femoral implant component and / or the metallic tibial implant component is additively manufactured from titanium or a titanium alloy. Titanium or a titanium alloy is ideally suited for the direct formation of surface areas facing the bone and in contact with the bone, as bone grows well into and onto surfaces formed from titanium or a titanium alloy. The natural surface roughness created by 3D printing proves to be additionally beneficial for this purpose. An alpha or beta titanium alloy, for example T16-A14-V or Ti-24Nb-4 Zr-8Sn, can be used as the titanium alloy.

[0023] By forming the previously formed coatings on articulating condylar surface areas, the tribological properties of titanium surfaces can be improved and, as already mentioned at the beginning, undesired bone growth in the soft tissue contact area can be prevented or at least inhibited.

[0024] The subject matter of the invention is also considered to be a respective implant part, i.e. a femoral implant part and / or a tibial implant part, which has a three-dimensional porous surface structure in the area of ​​bone contact in the surface areas facing the bone for the bone to grow into the implant part and which has a coating at least in some areas on the surface areas not in contact with the bone and not with the meniscus replacement part but in contact with soft tissue, by means of which coating a surface roughness of these surface areas is reduced.

[0025] Further features, details and advantages of the invention emerge from the appended patent claims and from the drawing and subsequent description of an embodiment of the orthopaedic knee joint prosthesis according to the invention.

[0026] In the drawing: Figure 1 shows an exploded view of an embodiment of an orthopaedic knee joint prosthesis according to the invention with a femoral implant part, a tibial implant part and a meniscus replacement part that can be fixed to the tibial implant part;

[0027] Figure 2 is a schematic, simplified sectional view of the femoral implant part;

[0028] Figure 3 is a side view of the tibial implant part with partial cross-section;

[0029] Figure 4 is a top view of the tibial implant part in the direction of arrow IV in Figure 3;

[0030] Figure 5 is a bottom view in the direction of arrow V in Figure 3;

[0031] Figure 6 shows schematically an additively manufactured three-dimensional porous metallic structure of an implant portion for bone tissue ingrowth; and

[0032] Figure 7 schematically illustrates a multi-layer coating.

[0033] Figure 1 shows an exploded view of an orthopedic knee joint prosthesis, designated overall by the reference symbol 2, with a femoral implant part 4, a tibial implant part 6 and a meniscus replacement part 8, which is typically anchored to the tibial implant part 6. The femoral implant part 4 comprises a not shown

[0034] Surface areas 10 facing the bone of the thigh (femur) and in contact with the bone, and furthermore articulating condylar surface areas 12 in sliding contact with the meniscus replacement part 8 as a sliding partner. Furthermore, the femoral implant part 4 comprises surface areas 14 which are not in contact with the bone and not with the meniscus replacement part 8, but are in soft tissue contact. These are surface areas 14 which are outside the articulating sliding contact with the meniscus replacement part, in particular surface areas 14 which flank the femoral implant part 4 horizontally laterally.

[0035] The tibial implant part 6 also has surface areas 16 facing the bone of the lower leg (tibia) and in contact with the bone. Furthermore, the tibial implant part 6 comprises surface areas 18 in contact with the meniscus replacement part 8, and finally, the tibial implant part 6 also has surface areas 20 that are not in contact with the bone and not with the meniscus replacement part 8, but are in soft tissue contact.

[0036] It can be seen from Figures 1 to 5 that the femoral implant part 4 has at least one dome- or shaft-shaped projection 22, and the tibial implant part 6 has an elongated projection 24, which each serve to engage and anchor to the femur or lower leg bone. The projection 24 of the tibial implant part 6 is also connected to a disc-shaped plateau part 26 of the tibial implant part 6 via cheek-shaped sections 25 extending in the vertical plane.

[0037] As can best be seen from Figure 4, the disc-shaped plateau part 26 comprises, facing away from the bone and facing the meniscus replacement part 8, a flatly extending recess 28 for inserting and in particular locking the area 28 of the meniscus replacement part 8 which is designed to be complementary thereto.

[0038] In the exemplary and preferred case shown, the femoral implant part 4 as well as the tibial implant part 6 are each formed with a three-dimensional porous surface structure 30 or 32 in the region of their bone contact. In both cases, this three-dimensional porous surface structure 30 and 32 extends macroscopically over at least 0.5 mm and in particular up to 20 mm, in particular up to 15 mm and in particular up to 10 mm in the depth direction into the respective implant part 4 or 6, which are each preferably manufactured using additive manufacturing processes.

[0039] The meniscus replacement part 8 forms, as a sliding partner to the femoral implant part 4, three-dimensionally shaped sliding surface regions 34 which are essentially complementary in shape to the condylar surface regions 12 of the femoral implant part 4 and which, like the entire meniscus replacement part 8, are formed from a polymer, in particular polyethylene. In order to reduce the frictional contact and thus the wear between the condylar surface regions 12 of the femoral implant part 4 and the meniscus replacement part 8, the articulating condylar surface regions 12 which are in sliding contact with the meniscus replacement part 8 have a hardening and wear-reducing, in particular multi-layered

[0040] Coating 38 on . This coating comprises several ceramic layers as well as a cover layer, for example and preferably based on zirconium nitride, as well as an adhesion-promoting layer on the base material of the femoral implant part 4 (described below by way of example in connection with Figure 7). The hardening and wear-reducing coating 38 can be formed in detail as described in EP 2 051 666 B1, so that the relevant content of this document with regard to the structure of the hardening and wear-reducing coating is incorporated by reference into the present application.

[0041] A corresponding hardening and wear-reducing coating 50 is present on the surface area 18 of the tibial implant part 6 that is in contact with the meniscus replacement part 8. This is advantageous because, despite the retaining connection, in particular the locking connection, between the meniscus replacement part 8 and the tibial implant part 6, micromovements occur between these components.

[0042] With the present invention it was found that surface areas of the femoral implant part 4 or the tibial implant part 6 which are in contact with the soft tissue can have a problematic effect on the soft tissue and in the worst case can lead to cell death if these surface areas 14 or 20 are too rough and, as a result of the articulating movement of the implant parts against each other, a relative movement takes place between these surface areas and the soft tissue. Therefore, with the present invention it is proposed to

[0043] Surface areas 14 of the femoral implant part 4 and surface areas 20 of the tibial implant part 6 outside the contact area with the bone and the meniscus replacement part are to be provided with a smoothing coating 52 and 54, respectively, by means of which the surface roughness of these surface areas 14, 20 in contact with the soft tissue is reduced. The aim is to achieve the smoothest possible surface so that relative movements do not lead, or at least lead to a significantly lower introduction of frictional energy into the soft tissue, which could prove problematic.

[0044] It has also proven advantageous that this coating 52 or 54, which reduces the surface roughness, is only deposited on outer webs, struts or ribs of the structure during application using the PVD process in the event of an unintentional coating of three-dimensionally porous surface areas 10 or 16 in contact with bone of the implant parts 4, 6, which does not noticeably impede the anchoring of bone material in the three-dimensionally porous structure.

[0045] It was further determined that the same layer structure can be used to form the smoothing, i.e., surface roughness-reducing, coating 52, 54 as is used to produce the hardening and wear-reducing coating 38 and 50, respectively, of the articulating condylar surface regions 12 of the femoral implant part 4 and the surface regions 18 of the tibial implant part 6 facing the meniscus replacement part 8.

[0046] Figure 7 shows schematically and by way of example a multi-layered coating structure, which is equally suitable for the construction of the respective hardening and wear-reducing coating 38, 50 and for the smoothing coating 52, 54. One can see a base material 60 of the respective implant part 4 or 6 and a particularly 30 to 200 x IO - 9 m thick adhesion-promoting layer 62, in particular based on titanium. Provided thereon are several ceramic layers 64, in particular made of two alternating materials. Finally, a ceramic surface layer 66, in particular based on zirconium nitride, is provided. As mentioned, this layer structure can be used both as a hardening and wear-reducing coating 38, 50 and as a smoothing coating 52, 54 exclusively in soft tissue contact.

Claims

Patent claims 1. Orthopaedic knee joint prosthesis (2) with a metallic femoral implant part (4), with a metallic tibial implant part (6), and with a meniscus replacement part (8) which forms a sliding partner for the femoral implant part (4) and is held on the tibial implant part (6), wherein the femoral implant part (4) in the implanted state has surface regions (10) facing the bone and in contact with the bone, wherein the femoral implant part (4) in the implanted state has articulating condylar surface regions (12) in sliding contact with the meniscus replacement part (8) as a sliding partner, wherein the tibial implant part (6) in the implanted state has surface regions (16) facing the bone and in contact with the bone, wherein the tibial implant part (6) in the implanted state is connected to the meniscus replacement part (8) has contacting surface areas (18),wherein the femoral implant part (4) and the tibial implant part (6) in the implanted state each have surface areas (14, 20) which are not in contact with the bone and not with the meniscus replacement part but are in contact with the soft tissue, wherein the femoral implant part (4) has at least in some areas a hardening and wear-reducing, in particular multi-layered, Coating (38), characterized in that the femoral implant part (4) and in particular also the tibial implant part (6) are manufactured additively by metallic 3D printing, that the femoral implant part (4) and / or the tibial implant part (6) has a three-dimensionally porous surface structure (30, 32) formed by the metallic 3D printing in the surface regions (10, 16) facing the bone for the bone to grow into the implant part (4, 6), and that the femoral implant part (4) and / or the tibial implant part (6) has, at least in some regions, a coating (52, 54) on the surface regions (14, 20) that are not in contact with the bone and not with the meniscus replacement part (8) but are in soft tissue contact, by means of which coating a surface roughness of these surface regions (14, 20) is reduced.

2. Orthopaedic knee joint prosthesis (2) according to claim 1, characterized in that the surface roughness of the surface regions (14, 20) which are not in contact with the bone and not with the meniscus replacement part but are in soft tissue contact and are provided with the coating (52, 54) is greater than or equal to a surface roughness of the articulating condylar surface regions (12) which are provided with the hardening and wear-reducing coating and are in sliding contact.

3. Orthopaedic knee joint prosthesis (2) according to claim 1 or 2, characterized in that the Surface roughness of the surface areas (14, 20) not in contact with the bone and not with the meniscus replacement part (8) but in contact with soft tissue and provided with the coating (52, 54) is at most 0.50 gm, in particular at most 0.40 gm, in particular at most 0.30 gm and in particular at least 0.04 gm, in particular at least 0.05 gm and in particular at least 0.10 gm, measured as Ra according to DIN / ISO 21920-3.

4. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the coating (52, 54) of the non-bony and non-bony meniscus replacement part (8) in contact but in soft tissue contact surface areas (14, 20) is produced by PVD (Physical Vapour Deposition) process.

5. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the tibial implant part (6) has a three-dimensionally porous surface structure (32) in the surface areas (16) facing the bone for the bone to grow into the implant part (6), and in that the tibial implant part (6) has, at least in some areas, a coating (54) on the surface areas (20) which are not in contact with the bone and not with the meniscus replacement part (8) but are in soft tissue contact, by means of which coating a surface roughness of these surface areas (20) is reduced.

6. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the hardening and wear-reducing, in particular multi-layer coating (38) of the articulating condylar surface regions (12) in sliding contact comprises a ceramic surface, in particular made of or based on zirconium nitride.

7. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the hardening and wear-reducing coating (38) of the articulating condylar surface regions (12) in sliding contact is formed in several layers and is bonded to the implant part (4) via an adhesion-promoting layer, in particular based on chromium or titanium.

8. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the hardening and wear-reducing coating (38) comprises layers based on chromium nitride (CrN) and / or based on chromium carbonitride (CrCN) and / or based on zirconium nitride (ZrN).

9. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the hardening and wear-reducing coating (38) comprises a cover layer based on zirconium nitride and inner layers based on chromium nitride (CrN) or chromium carbonitride (CrCN), whereby inner layers based on chromium nitride (CrN) and chromium carbonitride (CrCN) can alternate.

10. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the tibial implant part (6) has a hardening and wear-reducing, in particular multi-layered, coating (50) in surface areas (18) in contact with the meniscus replacement part (8) in order to reduce wear due to micromovements between the meniscus replacement part (8) and a plateau (26) of the tibial implant part (6).

11. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the coating of the surface areas not in contact with the bone and not with the meniscus replacement part but in contact with soft tissue is bonded to the implant part via a titanium-based adhesion-promoting layer.

12. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the coating of the surface regions (14, 20) which are not in contact with the bone and not with the meniscus replacement part (8) but are in contact with soft tissue is the same coating as the hardening and wear-reducing coating (38) of the articulating condylar surface regions (12) which are in sliding contact.

13. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the meniscus replacement part (8) has a polymer-based, in particular polyethylene-based, sliding surface which is in contact with the articulating condylar surface regions (12) of the femoral implant part (4).

14. Orthopaedic knee joint prosthesis (2) according to one or more of the preceding claims, characterized in that the metallic femoral Implant part (4) and / or the metallic tibial implant part (6) is additively manufactured from titanium or titanium alloy.

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