Orthopaedic knee joint prosthesis
The use of PEEK composite materials with a three-dimensional rib structure on orthopedic knee joint implants addresses wear and stability issues, enhancing fixation and reducing clinical complications.
Patent Information
- Application Number
- JP2024086214
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-07-17
- Filing Date
- 2024-05-28
- Publication Date
- 2025-01-29
AI Technical Summary
Existing orthopedic artificial knee joints made from cobalt chrome alloys and ceramics face issues with wear due to high mechanical stress and poor surface adaptability, leading to clinical complications.
The use of polyether ketone (PEEK) composite materials with a three-dimensional rib structure on the femoral and tibial implant parts, enhancing stability and allowing cement-free fixation by creating spaces for cement retention.
The PEEK composite materials with a three-dimensional rib structure improve the stability and strength of the implants, reducing wear and enhancing fixation to bone without the need for cement, thus improving clinical outcomes.
Smart Images
Figure 2025014107000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a femoral implant part for an orthopaedic knee prosthesis, which has at least one surface area that faces and contacts the bone in the implanted state, and to a tibial implant part for an orthopaedic knee prosthesis, an orthopaedic knee prosthesis and a manufacturing method for manufacturing the implant part or the orthopaedic knee prosthesis. [Background technology]
[0002] Femoral implant parts, tibial implant parts and such knee joint prostheses are known from the prior art. The materials used in such implant products consist essentially of cobalt-chromium or cobalt-chromium-molybdenum (Co-Cr-Mo) alloys or ceramic materials. The prostheses are generally fixed directly to the bone using bone cement or by bone engraftment.
[0003] Metal or ceramic materials may cause undesirable clinical problems.It is also known to manufacture implant products from, for example, polyetheretherketone (PEEK) polymer materials, since the latter have relatively good strength and stability, and good biocompatibility.
[0004] Due to the relatively high impact load, the very complex surface shape of the knee joint, and the relatively low degree of adaptation, the pressure on the knee joint surface is relatively high (10-20Mpa), which is much higher than the pressure on the hip joint surface (2-5Mpa), for example. These relatively high mechanical environmental conditions and requirements make such implant products quite susceptible to wear.
[0005] SUMMARY OF THE DISCLOSURE It is an object of the present invention to provide a femoral implant part for an orthopaedic knee prosthesis or an orthopaedic knee prosthesis, which is able to overcome the above-mentioned drawbacks. Summary of the Invention
[0006] This object is achieved by a femoral implant part according to claim 1.
[0007] One embodiment relates to a femoral implant part for an orthopaedic knee prosthesis, comprising: The femoral implant part has at least one surface area which faces and contacts the bone when implanted; at least a part of the femoral implant part consists, at least in the surface area in contact with the bone, of a plastic material, in particular of a polyaryletherketone (PAEK), in particular of a polyetheretherketone (PEEK) or a polyetheretherketone (PEEK) composite material, the femoral implant part has a three-dimensional surface structure in the surface area facing the bone, The three-dimensional surface structure includes at least one rib structure; In the rib structure, At least one first rib portion extending in a plane on the surface of the surface region, or a first rib extending in the plane on the surface of the surface region; The second rib portion extending in the plane on the surface of the surface region, or the second rib extending in the plane on the surface of the surface region, Within said plane, it extends at least partially in a number of different directions.
[0008] In this way, the rib structure is formed on the surface of the surface region, thereby forming the three-dimensional surface structure. The rib structure includes at least two or more ribs and / or at least two or more rib portions. These ribs or rib portions are arranged or formed on the surface of the surface region. That is, the ribs or rib portions protrude or extend from the surface of the surface region. The rib structure is understood to mean a strip-like structure that is curved and raised from the surface of the surface region.
[0009] The ribs or rib portions macroscopically protrude from the surface of the surface area of the implant part by at least 0.5 mm (in particular at most 3 mm). In the plane in which the ribs or rib portions extend, the ribs or rib portions have a width of at least 0.5 mm (in particular at most 3 mm). In said plane, the ribs or rib portions have any desired length (in particular at least 1 mm). The maximum length of the ribs or rib portions is for example limited by the specific arrangement of the ribs or rib portions and / or by the extension of the surface area.
[0010] The two rib sections may be associated with a common rib or with two different ribs. The ribs and rib sections may in principle extend in any manner in a plane, in particular straight, but also inclined (angled) or curved.
[0011] The rib structure on the surface improves the stability of the femoral implant part, which is advantageous in that implant products made of plastic materials, in particular polyetheretherketone (PEEK) or polyetheretherketone (PEEK) composite materials, have lower strength values than comparable implant products made of metals, such as cobalt-chromium alloys.
[0012] In principle, the femoral implant part may be fixed to the bone without the use of cement or using bone cement.
[0013] Additionally, the provision of a ribbed structure may be advantageous to improve cementation of the implant to the bone.
[0014] For example, the three-dimensional surface structure may comprise at least one (advantageously a plurality of) intermediate spaces formed between at least two of the ribs and / or rib sections of the rib structure, the intermediate spaces being bounded in one direction by the surface of the surface region and by ribs or rib sections respectively towards a corresponding direction, the intermediate spaces being open on the side facing the bone in the implanted state, thereby forming a space for receiving cement for cementing the implant product.
[0015] According to one embodiment, with respect to a reference axis extending in said plane, the rib or rib portion extends in said plane either longitudinally relative to said reference axis, transversely relative to said reference axis or obliquely relative to said reference axis, in particular in a curved or constant angle inclined relative to said reference axis, at an angle greater than 0° and less than 180°.
[0016] According to one embodiment, two or more ribs or two or more rib sections of the rib structure form at least one intersection, in particular a T-, Y-, cross or star-shaped intersection, which increases the stability or strength of the rib structure and thus the strength of the femoral implant part.
[0017] According to one embodiment, the ribs and / or rib sections of the rib structure are arranged according to the honeycomb pattern such that a total of six ribs and / or rib sections define each cell of the honeycomb pattern. In the case of a uniform honeycomb shape, the ribs and / or rib sections of each cell merge with each other at an angle of 120°. However, variations from the ideal honeycomb shape are also conceivable. Alternatively, a pattern similar to the honeycomb pattern may be formed. For example, the cells may be delimited by three or five ribs and / or rib sections in a triangular or pentagonal shape, or by seven or more ribs and / or rib sections. A rib structure configured according to such a pattern (in particular a honeycomb pattern) has a particularly advantageous degree of strength or stability.
[0018] According to one embodiment, the ribs and / or rib portions have a helical shape in said plane. In this connection, it may be advantageous if said surface area is completely surrounded in the edge area by one or more ribs and / or rib portions, which provides a space for receiving the cement.
[0019] The object of the invention set out at the outset is also achieved by a tibial implant part for an orthopaedic knee prosthesis according to claim 7. The tibial implant part has at least one surface area which faces and contacts the bone in the implanted state. At least a part of the tibial implant part consists, at least in the bone-contacting surface area, of a plastic material, in particular polyetheretherketone (PEEK) or a polyetheretherketone (PEEK) composite material, which comprises, in the bone-facing surface area, a three-dimensional surface structure, which comprises at least one rib structure, in which at least one first rib portion extending in a plane on the surface of the surface area or a first rib extending in the plane on the surface of the surface area and a second rib portion extending in the plane on the surface of the surface area or a second rib extending in the plane on the surface of the surface area extend at least partially in a plurality of different directions in the plane.
[0020] According to a further embodiment, the tibial implant part, i.e. the surface area of the tibial implant part, is configured similarly to the surface area described above for the femoral implant part.
[0021] For example, the three-dimensional surface structure may comprise at least one (and advantageously a plurality of) intermediate spaces formed between at least two of the ribs and / or rib portions of the rib structure.
[0022] According to one embodiment, with respect to a reference axis extending in said plane, the rib or rib portion extends in said plane either longitudinally relative to said reference axis, transversely relative to said reference axis or obliquely relative to said reference axis, in particular in a curved or constant angle inclined relative to said reference axis, at an angle greater than 0° and less than 180°.
[0023] According to one embodiment, two or more ribs or two or more rib sections of the rib structure form at least one intersection, in particular a T-shaped, Y-shaped, cross-shaped or star-shaped intersection.
[0024] According to one embodiment, the ribs and / or rib portions of the rib structure are arranged according to a honeycomb pattern such that a total of six ribs and / or rib portions define each cell of the honeycomb pattern.
[0025] According to one embodiment, the ribs and / or rib portions have a helical shape in said plane. In this connection, it may be advantageous if the surface area is completely surrounded in an edge area by one or more ribs and / or rib portions. The object stated at the beginning is also achieved by an orthopaedic knee prosthesis according to claim 9, which comprises an above-mentioned femoral implant part and / or an above-mentioned tibial implant part, optionally with a meniscus replacement part (meniscus replacement component) forming a sliding counterpart of the femoral implant part and held on the tibial implant part.
[0026] Further embodiments relate to a method for manufacturing the above-mentioned femoral implant part and / or the above-mentioned tibial implant part, for example the femoral implant part and / or the tibial implant part are manufactured by injection molding or additive manufacturing, where in an injection molding process the three-dimensional surface structure is generated by injecting material into a corresponding mold cavity, or in additive manufacturing (3D printing) the three-dimensional surface structure is generated by adding material to the surface in layers.
[0027] Further features, details and advantages of the invention can be found in the attached claims, the drawings and the following description of an embodiment of an orthopedic knee prosthesis according to the invention, where the same reference signs in different drawings indicate the same elements or at least functionally equivalent elements. In the description of the individual drawings, reference may also be made to elements from other drawings. The attached drawings are as follows: [Brief description of the drawings]
[0028] [Figure 1]1 is an exploded view of an embodiment of an orthopaedic knee prosthesis according to the present invention, comprising a femoral implant part, a tibial implant part, and a meniscus replacement part fixable to the tibial implant part; FIG. [Diagram 2] FIG. 2 shows a femoral implant part for an orthopaedic knee prosthesis according to the first embodiment. [Diagram 3] 13A-13C show femoral implant parts for an orthopaedic knee prosthesis according to another embodiment. [Figure 4] 13 shows a femoral implant part for an orthopaedic knee prosthesis according to yet another embodiment. FIG. [Diagram 5] FIG. 2 is a diagram showing a three-dimensional surface structure according to the first embodiment. [Figure 6] FIG. 13 is a diagram showing a three-dimensional surface structure according to another embodiment. [Figure 7] FIG. 13 is a diagram showing a three-dimensional surface structure according to yet another embodiment. [Figure 8] FIG. 2 is a plan view of the tibial implant part seen from below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Figure 1 shows an orthopaedic knee prosthesis in an exploded view, generally designated by the reference number 2. The knee prosthesis 2 comprises a femoral implant part 4, a tibial implant part 6 and a meniscus replacement part 8. The meniscus replacement part 8 can typically be fixed to the tibial implant part 6. The femoral implant part 4 comprises a surface area 10 which faces and contacts the femur (not shown) bone of the thigh.
[0030] The tibial implant part 6 also has a surface area 12 which faces the bone of the lower leg (tibia) and comes into contact with said bone.
[0031] The femoral implant part 4 has at least one dome- or shaft-shaped projection 14, which serves for engagement and fixation on the femur. The tibial implant part 6 has an elongated projection 16, which serves for engagement and fixation on the lower leg bone (tibia). The projection 16 of the tibial implant part 6 is attached to a disk-shaped plateau 20 of the tibial implant part 6 via a cheek- or wing-shaped portion 18 extending in a vertical plane.
[0032] In a preferred embodiment shown by way of example, the femoral implant part 4 is configured with a three-dimensional surface structure 22 in its bone contact area or surface area 10, and the tibial implant part 6 is configured with a three-dimensional surface structure 24 in its bone contact area or surface area 12. In both cases, the three-dimensional surface structure 22, 24 protrudes macroscopically by at least 0.5 mm (e.g. at most 3 mm) from the surfaces of the surface areas 10, 12 of the implant parts 4, 6.
[0033] 2 to 7, various advantageous embodiments of the three-dimensional surface structure 22 are explained below using the example of a femoral implant part 4. The three-dimensional surface structure 24 of the tibial implant part 6 can be configured in a similar manner.
[0034] Figure 2 shows a femoral implant part 4. In this example, the femoral implant part 4 comprises a number of bone-contacting surface areas 10, each of which is provided with a three-dimensional surface structure 22. In this example, the surface areas 10-1, 10-2 are shown. Further surface areas, for example in the region of the femoral condyles, are not visible in Figure 2. Other surface areas may also be provided with a three-dimensional surface structure (not shown).
[0035] The three-dimensional surface structure 22 of the surface regions 10-1, 10-2 includes a rib structure 26. This type of rib structure 26 comprises a plurality of ribs 28 and / or a plurality of rib portions 30. A rib 28 is understood to mean, for example, a strip-like structure extending without interruption and protruding from the surface. A rib portion 30 is, for example, any part of such a rib 28. In particular, a rib portion 30 is a portion extending from an intersection 32 where at least two ribs 28 intersect or join to another intersection 32.
[0036] In the embodiment according to Fig. 2, the rib structure 26 of the surface regions 10-1, 10-2 comprises ribs 28-1 extending longitudinally relative to the reference axis 34 and ribs 28-2 extending transversely relative to the reference axis 34. Both surface regions 10-1, 10-2 are completely surrounded in an edge region 36 by a peripheral rib 28-3.
[0037] Alternatively, the ribs 28 and / or ribbed portions 30 may extend obliquely relative to the reference axis 34 .
[0038] In the example shown in FIG. 2, a longitudinally extending rib 28-1 and a transversely extending rib 28-2 intersect at a right angle at an intersection 32. Thus, the illustrated intersection 32 is formed as a cross-shaped intersection. Alternatively, the multiple ribs 28 may intersect or merge at any other angle. The number of intersecting or merging ribs 28 is also arbitrary. Furthermore, the intersection shape of the ribs 28 may be, for example, a T-shaped, Y-shaped, or star-shaped intersection shape, or any other intersection shape.
[0039] 2, a plurality of intermediate spaces 38 are formed between the plurality of ribs 28 (28-1, 28-2, 28-3) and the plurality of rib portions 30 in the rib structure 26. The intermediate spaces 38 are bounded on one side by the surface of the surface region 10 (10-1, 10-2), and are bounded on corresponding sides by the ribs 28 (28-1, 28-2, 28-3) or the rib portions 30. The intermediate spaces 38 are open on a side facing the bone in an implanted state.
[0040] Fig. 3 shows another embodiment. In the example of Fig. 3, surface regions 10-1 and 10-2 are shown. The three-dimensional surface structure 22 of the surface regions 10-1 and 10-2 includes a rib structure 26. The three-dimensional surface structure 22 comprises a plurality of ribs 28 and / or a plurality of rib portions 30 arranged according to a honeycomb pattern. In the example of Fig. 3, six rib portions 30-1, 30-2, 30-3, 30-4, 30-5, and 30-6 delimit the cells 40 of the honeycomb pattern.
[0041] The cells 40 of the honeycomb pattern form the intermediate spaces 38 .
[0042] Fig. 4 shows yet another embodiment. In the example of Fig. 4, surface regions 10-1 and 10-2 are shown. The three-dimensional surface structure 22 of the surface regions 10-1 and 10-2 includes a rib structure 26.
[0043] The rib structure 26 of the surface region 10-1 includes a rib 28-4 having a helical shape. The rib 28-4 comprises a plurality of rib portions 30 extending in different directions, at least partially according to the helical shape in a plane. The surface region 10-1 is completely surrounded in an edge region 36 by a peripheral rib 28-3.
[0044] The rib structure 26 of the surface region 10-2 includes a plurality of ribs 28-1 extending longitudinally relative to a reference axis 34.
[0045] Surface region 10-2 is also completely surrounded at edge region 36 by peripheral rib 28-3.
[0046] Figures 5, 6, and 7 show cut-outs of the three-dimensional surface structures of Figures 2, 3, and 4, respectively.
[0047] In principle, in the case of the femoral implant part 4, a combination of the illustrated three-dimensional surface structures or other three-dimensional surface structures in different surface regions is possible. Combinations within a specific surface region are also possible. In a surface region, the surface structures, the arrangement of ribs or rib sections or the pattern do not necessarily have to cover the entire surface region.
[0048] FIG. 8 shows the tibial implant part 6, with the surface area 12 in contact with the bone in the implanted state, seen from below. According to FIG. 8, the tibial implant part 6 comprises a continuous surface area 12. However, the surface area 12 may also be divided into a number of individual surface areas 12. The surface area 12 may comprise a surface structure configured similarly to the three-dimensional surface structures shown in FIGS. 2 to 7, or may comprise a different three-dimensional surface structure. In this example, the three-dimensional surface structure comprises a rib structure 26 with ribs 28 (28-1, 28-2) and a rib portion 30, which run obliquely with respect to a reference axis 34. Furthermore, the edge area 36 is completely bounded by a peripheral rib 28-3.
Claims
1. A femoral implant part (4) for an orthopaedic knee prosthesis (2), comprising: The femoral implant part (4) has at least one surface area (10) which faces and contacts the bone in an implanted state, at least a part of the femoral implant part (4), at least in the surface area (10) in contact with the bone, consists of a plastic material, in particular polyetheretherketone (PEEK) or a polyetheretherketone (PEEK) composite material, the femoral implant part (4) comprises a three-dimensional surface structure (22) in the surface area (10) facing the bone, The three-dimensional surface structure (22) includes at least one rib structure (26), In the rib structure (26), at least one first rib portion (30) extending in a plane on the surface of the surface region (10), or a first rib (28, 28-1) extending in the plane on the surface of the surface region (10); The second rib portion (30) extending in the plane on the surface of the surface region (10), or the second rib (28, 28-2) extending in the plane on the surface of the surface region (10) means: Extending at least partially in a plurality of different directions within said plane; Femoral implant parts.
2. the three-dimensional surface structure (22) comprises at least one intermediate space (38) formed between at least two of the ribs (28, 28-1, 28-2, 28-3) and / or rib portions (30) of the rib structure (26); A femoral implant part according to claim 1.
3. With respect to a reference axis (34) extending in said plane, the ribs (28, 28-1, 28-2, 28-3) or the rib portions (30) extend in said plane either longitudinally relative to the reference axis (34), transversely relative to the reference axis (34) or obliquely relative to the reference axis (34), in particular at an angle to the reference axis (34) that is greater than 0° and smaller than 180°, in a curved or constant manner. A femoral implant part according to claim 1 or 2.
4. two or more ribs (28, 28-1, 28-2, 28-3) or two or more rib sections (30) in the rib structure (26) form at least one intersection (32), in particular a T-shaped, Y-shaped, cross-shaped or star-shaped intersection; A femoral implant part according to any one of claims 1 to 3.
5. the ribs (28) and / or rib portions (30) of the rib structure (26) are arranged according to the honeycomb pattern such that a total of six ribs (28) and / or rib portions (30, 30-1, 30-2, 30-3, 30-4, 30-5, 30-6) define each cell (40) of the honeycomb pattern; A femoral implant part according to any one of claims 1 to 4.
6. the ribs (28, 28-4) and / or the rib portion (30) of the rib structure (26) have a helical shape in the plane; A femoral implant part according to any one of claims 1 to 5.
7. A tibial implant part (6) for an orthopaedic knee prosthesis (2), comprising: The tibial implant part (6) has at least one surface area (12) which faces and contacts the bone in an implanted state, at least a part of the tibial implant part (6) consists, at least in the surface area (12) in contact with the bone, of a plastic material, in particular of polyetheretherketone (PEEK) or a polyetheretherketone (PEEK) composite material, the tibial implant part (6) comprises a three-dimensional surface structure (24) in the surface area (12) facing the bone, The three-dimensional surface structure (24) includes at least one rib structure (26); In the rib structure (26), at least one first rib portion (30) extending in a plane on the surface of the surface region (12) or a first rib (28, 28-1) extending in the plane on the surface of the surface region (12); The second rib portion (30) extending in the plane on the surface of the surface region (12), or the second rib (28, 28-2) extending in the plane on the surface of the surface region (12) means: Extending at least partially in a plurality of different directions within said plane; Tibial implant parts.
8. The tibial implant part (6) is configured as claimed in any one of claims 2 to 6. A tibial implant part according to claim 7.
9. An orthopedic knee prosthesis (2), comprising: A femoral implant part (4) according to any one of claims 1 to 6 and / or a tibial implant part (6) according to claim 7 or claim 8, Optionally, a meniscus replacement part (8) which forms a sliding counterpart of said femoral implant part (4) and is held on said tibial implant part (6). Artificial knee joint.
10. A method for manufacturing a femoral implant part (4) according to any one of claims 1 to 6 and / or a tibial implant part (6) according to claim 7 or claim 8, comprising: the femoral implant part (4) and / or the tibial implant part (6) are manufactured by injection molding or additive manufacturing; method.