Ankle joint prosthesis implantation system based on zirconium-niobium alloy

Abstract

The invention relates to the technical field of joint prostheses, in particular to an ankle joint prosthesis implantation system based on zirconium-niobium alloy, which comprises a tibia prosthesis (10), a talus prosthesis (30) and a liner (20), the tibia prosthesis (10) and the talus prosthesis (30) are both made of zirconium-niobium alloy material and are integrally formed by 3D printing, the tibia prosthesis (10) comprises a tibia body (101), and the liner (20) is arranged on the tibia body (101). The first bone contact layer (100) is integrally formed on the tibia body (101), and the first bone contact layer (100) is of a porous structure of which the pore diameter is gradually reduced from outside to inside; the talus prosthesis (30) comprises a talus body (301) and a second bone contact layer (300) integrally formed on the talus body (301), and the second bone contact layer (300) is of a porous structure with the aperture gradually reduced from outside to inside.

Description

[0001] Priority Application This application claims priority to a Chinese patent application for invention, Application No. 202510295777.3, filed on March 13, 2025, and titled "An Ankle Prosthesis Implantation System", which is incorporated herein by reference in its entirety. Technical Field

[0002] The present invention relates to the technical field of joint prostheses, and particularly to an ankle prosthesis implantation system based on zirconium niobium alloy. Background Art

[0003] Due to arthritis, anterior ankle surgery, fractures, osteoarthritis, and / or one or more other conditions, the ankle joint may become severely damaged and painful. Options for treating an injured ankle include anti-inflammatory painkillers, braces, physical therapy, arthrodesis, and total ankle replacement.

[0004] Total ankle replacement is a type of joint replacement surgery and is currently an effective treatment for end-stage joint diseases in clinical practice. Currently, total ankle replacement includes two components, a tibial implant and a talar implant. The implant includes a joint articulation surface that is sized and configured to mimic the range of motion of the ankle joint. For example, the talar implant may include an implant sized and configured to mimic the talar dome, and the tibial implant may include a joint articulation surface sized and configured to mimic the tibial joint articulation. The joint articulation component may be positioned between the talar implant and the tibial implant.

[0005] For example, U.S. Patent Application Publication No. US20230380981A1 discloses a talar implant system including a body. The body includes a bone contact surface and a joint articulation surface positioned opposite the bone contact surface. The body defines at least one angled fastener hole extending along a longitudinal axis from the joint articulation surface through the body to the bone contact surface. The joint articulation surface is configured to mimic the joint articulation of the talar dome. The fastener is sized and configured to be received within at least one fastener hole at a first angle relative to the longitudinal axis of the fastener hole. The fastening cap is sized and configured to be received within the proximal end of at least one fastener hole. The fastening cap couples the body to the fastener.

[0006] For another example, Chinese Patent Application with Publication No. CN105722478A discloses a talar dome, which is used as an element for total ankle arthroplasty to fit on the resected talus. The talar dome has an integral talar body, and the talar body has a smooth and circular upper joint side facing the tibia and a lower mounting side. The lower mounting side has mutually inclined surfaces complementary to the flat surface of the resected talus. On the lower or mounting side, the talar dome has at least two studs that are integral with the dome body and project rigidly from the dome body. Each stud that tapers into a pointed tip along the flat surface is embedded in the talus to operably attach the talar dome to the talus. At least one flat surface of each stud is perpendicular to the sagittal plane to resist the anteroposterior displacement of the talar dome until healing occurs.

[0007] For yet another example, Chinese Patent Application with Publication No. CN110198684A discloses an implant, including a component for fixedly attaching to a bone. A lower channel layer of porous material is disposed on a first side of the component for fixedly attaching. At least one strut is disposed on the lower channel layer. The at least one strut has a first surface contacting the lower channel layer and a second surface opposite to the first surface. The at least one strut includes non-porous material. An additional layer of porous material fills a corresponding volume adjacent to the at least one strut. The additional layer extends from the first side of the lower channel layer to a predetermined height at the second surface of the at least one strut or a predetermined height above the second surface of the at least one strut.

[0008] However, since joint prostheses are implanted in the human body for a long time, under the long-term action of the complex physiological and mechanical environment in the body, soft materials, such as ultra-high molecular weight polyethylene (UHMWPE), will generate a large number of wear debris particles due to joint surface wear. The accumulation of wear debris can cause a series of tissue reactions, leading to osteolysis, aseptic loosening, and prosthesis failure. Moreover, for metal joint materials such as cobalt-chromium alloy, nickel-titanium alloy, and stainless steel alloy, toxic metal ions, such as Cr, Ni, Mn, Mo, and V ions, will be released under the long-term combined action of friction and corrosion in the body. On the one hand, it will cause allergic reactions; on the other hand, there are also other unknown potential hazards.

[0009] Therefore, the prior art also proposes to provide a porous structure at the bone-implant junction, which can promote the growth of bone in or on the implant. For example, plasma spraying can be used on the outer side of the implant to provide a rough surface for bone in-growth or attachment. The "BIOFOAM" porous titanium material from Wright Medical in Memphis, Tennessee, is another structure that promotes bone in-growth.

[0010] Zirconium niobium alloy has excellent corrosion resistance, mechanical properties and good biocompatibility, and is gradually being applied in the field of medical devices. Zirconium niobium alloy can react with elements such as N, C, O, etc. to form a hard oxide layer on the surface, which has excellent wear resistance and low wear rate, can reduce the wear of soft materials, that is, has excellent wear resistance at the joint interface; and the oxide layer can reduce the release of metal ions and has excellent biocompatibility, that is, has excellent biocompatibility at the bone integration interface. The joint surface with low wear rate is organically combined with the bone integration interface (trabecular bone) with excellent bone ingrowth performance, which can enable the prosthesis to simultaneously achieve the advantages of both interfaces. Therefore, in the prior art, it is proposed to use 3D printing technology and zirconium niobium alloy to prepare an ankle joint prosthesis system.

[0011] For example, the Chinese invention patent with the publication number CN112274301B discloses a zirconium niobium alloy ankle joint prosthesis system with an oxide layer and a preparation method thereof. Using zirconium niobium alloy powder as raw material, the intermediate products of the talus component and the tibia component are obtained by 3D printing and integrally formed, and after hot isostatic pressing, cryogenic treatment and surface oxidation, the talus component or the tibia component is obtained. Among them, the lower surface of the talus component body and the outer surfaces of two first fixing columns are provided with trabecular bone, and the upper surface of the tibia component body and the outer surfaces of two second fixing columns are provided with trabecular bone; the pore size of the trabecular bone is 0.80 mm, the porosity is 72%, and the through-hole rate is 100%; the thickness is 0.5 mm.

[0012] Another example is the Chinese utility model patent with the publication number CN204863564U, which discloses a fully organic polymer material ankle joint prosthesis, including a tibial tray prosthesis, a tibial pad and an ankle bone prosthesis. Among them, the proximal end of the tibial tray prosthesis is a rough or porous layer with a thickness of 0.5 - 1.0 mm, and the rough or porous layer is composed of a biocompatible metal or its alloy, such as cobalt-chromium-molybdenum alloy and zirconium niobium alloy, etc.

[0013] Another example is the Chinese invention patent application with the publication number CN116919676A, which discloses an integrated ankle joint prosthesis system, including a tibia component and a talus component; among them, the tibia main body of the tibia component and the talus main body of the talus component are both made of zirconium niobium alloy.

[0014] However, the performance of the above-mentioned ankle joint prosthesis prepared based on zirconium niobium alloy still needs to be improved. Summary of the Invention

[0015] The purpose of the present invention is to provide an ankle joint prosthesis implantation system based on zirconium niobium alloy, which partially solves or alleviates the defects of the prior art, can provide space for the ingrowth of bone cells, promote bone integration, and the designed porous structure is closer to the mechanical properties of the human bone, can reduce the elastic modulus of the prosthesis, is closer to the mechanical properties of the human bone, and reduces the stress shielding effect, thereby improving the long-term stability and anti-loosening ability of the prosthesis.

[0016] To achieve the above object, the present invention provides the following technical solutions: The present invention provides an ankle joint prosthesis implantation system based on zirconium niobium alloy, including a tibial prosthesis, a talar prosthesis and a spacer. Both the tibial prosthesis and the talar prosthesis are made of zirconium niobium alloy material and integrally formed by 3D printing. Among them, the tibial prosthesis includes a tibial body, and a first bone contact layer integrally formed on the tibial body. The first bone contact layer is a porous structure with a gradually decreasing pore diameter from outside to inside. The first bone contact layer at least includes: a first bone contact sub-layer, a first support sub-layer and a first body connection sub-layer stacked from outside to inside. Among them, the pore diameter of the first bone contact sub-layer is 400um - 600um, the pore diameter of the first support sub-layer is 200um - 400um; the pore diameter of the first body connection sub-layer is 0um - 200um; The talar prosthesis includes a talar body, and a second bone contact layer integrally formed on the talar body. The second bone contact layer is a porous structure with a gradually decreasing pore diameter from outside to inside. The second bone contact layer at least includes: a second bone contact sub-layer, a second support sub-layer and a second body connection sub-layer stacked from outside to inside. Among them, the pore diameter of the second bone contact sub-layer is 400um - 600um, the pore diameter of the second support sub-layer is 200um - 400um; the pore diameter of the second body connection sub-layer is 0um - 200um.

[0017] In some embodiments, the thickness of the first bone contact layer is 1 - 3mm; and / or, the thickness of the second bone contact layer is 1 - 3mm.

[0018] In some embodiments, the tibial prosthesis further includes a press-fit central cage disposed on the first bone contact layer, and a plurality of tibial fixing columns surrounding the press-fit central cage; and both the press-fit central cage and the tibial fixing columns are porous structures with a gradually decreasing pore diameter from outside to inside; among them, The tibial fixing column at least includes: a third bone contact layer, an intermediate layer and a central layer stacked from outside to inside. Among them, the pore diameter of the third bone contact layer is 400um - 600um, the pore diameter of the intermediate layer is 200um - 400um; the pore diameter of the central layer is 0um - 200um; and / or, the pore diameter of the press-fit central cage is 600um.

[0019] In some embodiments, the distance ratio between the front and rear sides of the press-fit central cage and the first bone contact layer is: 0.85 - 0.88; and / or, the distance ratio between the left and right sides of the press-fit central cage and the first bone contact layer is: 1.03 - 1.07.

[0020] In some embodiments, an annular groove is provided along the circumferential direction of one end of the tibial fixing post away from the first bone contact surface.

[0021] In some embodiments, the press-fit central cage is a hollow structure, and a plurality of through holes are uniformly arranged along the circumferential direction on the side wall of the hollow structure.

[0022] In some embodiments, the talus prosthesis further includes: a plurality of talus fixing posts arranged on the second bone contact layer, the talus fixing posts being a porous structure with a gradually decreasing pore diameter from the outside to the inside, and the talus fixing posts at least including: a third bone contact layer, an intermediate layer, and a central layer stacked from the outside to the inside, wherein the pore diameter of the third bone contact layer is 400um - 600um, the pore diameter of the intermediate layer is 200um - 400um; the pore diameter of the central layer is 0um - 200um.

[0023] In some embodiments, the talus prosthesis is a curved talus prosthesis or a flat-cut talus prosthesis.

[0024] In some embodiments, the first bone contact sub-layer includes a first reinforcement area surrounding the press-fit central cage and the tibial fixing post, a first growth area respectively located on the front and rear sides of the first reinforcement area, and connection areas respectively located on the left and right sides of the first reinforcement area, wherein, the pore diameter of the first reinforcement area is greater than that of the first growth area; the pore diameter of the first growth area is greater than that of the connection area; and the porosity of the first reinforcement area is greater than that of the first growth area; the porosity of the first growth area is greater than that of the connection area.

[0025] In some embodiments, the second bone contact layer includes a second reinforcement area surrounding the talus fixing post, and a second growth area surrounding the second reinforcement area; wherein, the pore diameter of the second reinforcement area is greater than that of the second growth area; and the porosity of the second reinforcement area is greater than that of the second growth area.

[0026] In some embodiments, the porosities of the first bone contact sub-layer (1001), the first support sub-layer (1002), and the first body connection sub-layer (1003) are respectively: 20% - 30%, 30% - 50%, 50% - 70%.

[0027] In some embodiments, the porosity of the first reinforcement area (1001-1) is 20% - 23%, the porosity of the first growth area (1001-3) is 24% - 26%, and the porosity of the connection area (1001-3) is 26% - 30%.

[0028] In some embodiments, the porosity of the second bone contact sub-layer (3001), the second support sub-layer (3002), and the second body connection sub-layer (3003) are respectively: 10% - 20%, 20% - 40%, 40% - 60%.

[0029] In some embodiments, the porosity of the second reinforcement region (3001-1) is 20% - 25%, and the porosity of the first growth region (1001-3) is 28% - 30%.

[0030] Beneficial effects: By providing a porous structure with a gradually decreasing pore size, that is, the porous structure includes a bone contact sub-layer that is beneficial for bone growth to a solid body (such as a talus body and a tibia body) with a non-porous structure, and a support sub-layer and a connection sub-layer are arranged in between for transition. While providing growth space for the ingrowth of bone cells to promote bone integration, the elastic modulus of the prosthesis is reduced, making it closer to the mechanical properties of the human bone, reducing the stress shielding effect, and thus improving the long-term stability and anti-loosening ability of the prosthesis. For example, a porous structure with a thickness of 1 - 3 mm and a pore size of 200 - 600 microns provides sufficient space for the ingrowth of bone cells, effectively promoting bone integration, and is also most suitable for the ingrowth of bone cells and angiogenesis, and the prosthesis structure has high stability.

[0031] Furthermore, by dividing the bone contact sub-layer into regions and further setting a porous structure with different pore sizes and / or porosities, the regions with more concentrated stress can be ensured. For example, the first reinforcement region has better elastic modulus and mechanical properties, thereby ensuring long-term stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale. Obviously, the following described drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a schematic structural diagram of the first perspective of the ankle joint prosthesis implantation system based on zirconium niobium alloy of the present invention; Figure 2 It is a schematic structural diagram of the second perspective of the ankle joint prosthesis implantation system based on zirconium niobium alloy of the present invention; Figure 3 is Figure 1Schematic structural diagram of the first embodiment of the tibial prosthesis in the shown ankle joint prosthesis implantation system; Figure 4a To reflect Figure 3 Schematic diagram of the porous structure of the first bone contact layer on the shown tibial prosthesis; Figure 4b Schematic diagram to reflect the setting of the bone growth induction layer on the first bone contact layer of the tibial prosthesis; Figure 5a To reflect Figure 3 Schematic diagram of the porous structure of the tibial fixation post on the shown tibial prosthesis; Figure 5b Schematic diagram to reflect the setting of the bone growth induction layer on the tibial fixation post / talus fixation post; Figure 6 For Figure 1 Schematic structural diagram of the talus prosthesis in the shown ankle joint prosthesis implantation system; Figure 7a For Figure 6 Schematic diagram of the porous structure of the second bone contact layer on the shown talus prosthesis; Figure 7b Schematic diagram to reflect the setting of the bone growth induction layer on the second bone contact layer of the talus prosthesis; Figure 8 Schematic structural diagram of the second embodiment of the tibial prosthesis in the ankle joint prosthesis implantation system based on zirconium niobium alloy of the present invention; Figure 9 Schematic diagram of the distribution of different functional regions on the first bone contact sublayer in the ankle joint prosthesis implantation system based on zirconium niobium alloy of the present invention: the first reinforcement region, the first growth region, and the connection region; Figure 10 Schematic diagram of the distribution of different functional regions on the second bone contact sublayer in the ankle joint prosthesis implantation system based on zirconium niobium alloy of the present invention: the second reinforcement region and the second growth region; Figure 11 Schematic structural diagram of the substrate of the ankle joint prosthesis implantation system based on zirconium niobium alloy of the present invention from the first perspective; Figure 12 Schematic structural diagram of the substrate of the ankle joint prosthesis implantation system based on zirconium niobium alloy of the present invention from the second perspective.

[0034] In the figure: 10 tibial prosthesis: 100 first bone contact layer: 1001 first bone contact sublayer, first support sublayer 1002, first body connection layer 1003, 101 tibial body, 102 press-fit central cage, 103 tibial fixation post: 1031 third bone contact sublayer, 1032 intermediate layer, 1033 central layer, 104 flank, 105 groove; 1001-1 first reinforcement region, 1001-2 first growth region, 1001-3 connection region; 20 Gasket: 201 First protrusion, 202 Second protrusion; 30 Talus prosthesis: 301 Talus body: 300 Second bone contact layer: 3001 Second bone contact sub-layer, second support sub-layer 3002, second body connection layer 3003, 3001-1 Second reinforcement area, 3001-2 Second growth area, 302 Talus fixing post. Detailed implementation

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] In this document, suffixes such as "module", "component" or "unit" used to represent elements are only for the convenience of explaining the present invention and have no specific meaning in themselves. Therefore, "module", "component" or "unit" can be used interchangeably.

[0037] In this document, the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", "front", "rear", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0038] In this document, unless otherwise clearly specified and limited, terms such as "installation", "provided with", "connection", etc. shall be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In this document, "and / or" includes any and all combinations of one or more of the listed related items.

[0040] In this document, "a plurality" means two or more, that is, it includes two, three, four, five, etc.

[0041] As used herein, "solid" refers to a structure without a porous structure or a structure with a pore size of 0 obtained by 3D printing technology. For example, the tibial body and the talar body.

[0042] Compared with the prior art of preparing ankle joint prostheses using zirconium niobium alloy, in the present invention, the zirconium niobium alloy material is printed by 3D printing technology to form a solid body (such as the tibial body and the talar body) and a porous structure located on the solid body (used as a bone contact layer in contact with the bone, for example, the first bone contact layer, the second bone contact layer, and the third bone contact layer). Moreover, the pore size of the porous structure decreases gradually from the outside to the inside (i.e., gradually decreases from the bone contact surface to the solid body). The porous structure with a gradually decreasing pore size is closer to the mechanical properties of the human bone, and the bone contact surface of the porous structure provides a sufficient attachment surface for bone ingrowth, promoting bone ingrowth and significantly improving the long-term stability and anti-loosening ability of the prosthesis.

[0043] Furthermore, in the present invention, a press-fit central cage and tibial fixation posts with porous structures are provided on the tibial prosthesis. The press-fit central cage is a cylindrical hollow structure, which is beneficial for bone grafting and the growth of new bone tissue, thereby enhancing the connection strength between the tibial prosthesis and the tibia. It is also beneficial for preserving bone mass, increasing the bonding area with the tibia, enhancing stability, dispersing stress, simplifying the operation, and improving durability. At the same time, a plurality of tibial fixation posts surround the press-fit central cage and are provided with grooves. On the one hand, it is beneficial for optimizing stress distribution and protecting the surrounding bone mass. On the other hand, the grooves are beneficial for improving the stability in the early stage of implantation and preventing the early detachment of the tibial prosthesis.

[0044] Example 1: Refer to Figure 1 and Figure 2 , the ankle joint prosthesis implantation system based on zirconium niobium alloy of the present invention includes a tibial prosthesis 10, a talar prosthesis 30, and a liner 20. Among them, both the tibial prosthesis 10 and the talar prosthesis 30 are integrally formed by using zirconium niobium alloy powder through 3D printing; the liner 20 is made of highly cross-linked polyethylene, which is more wear-resistant than traditional ultra-high molecular weight polyethylene.

[0045] Refer to Figure 3 , in this embodiment, the tibial prosthesis 10 includes a tibial body 101 and a first bone contact layer 100 integrally formed on the tibial body 101. The first bone contact layer 100 is a porous structure with a gradually decreasing pore size from the outside to the inside; a press-fit central cage 102 is further provided on the first bone contact layer 100, and a plurality of tibial fixation posts 103 surround the press-fit central cage 102. The axes of the press-fit central cage 102 and the fixation posts 103 are both perpendicular to the plane where the first bone contact layer 100 is located; and the press-fit central cage 102 and the tibial fixation posts 103 are also porous structures with a gradually decreasing pore size from the outside to the inside.

[0046] Preferably, the first bone contact layer 100 of the porous structure is a multi-layer structure with a gradually decreasing pore size, and the overall thickness is 1 mm - 3 mm. Specifically, refer to Figure 4a , the above-mentioned first bone contact layer 100 at least includes: a first bone contact sub-layer 1001, a first support sub-layer 1002, and a first body connection sub-layer 1003 that are stacked from the outside to the inside. Among them, the pore size of the first bone contact sub-layer 1001 is 400 um - 600 um, the pore size of the first support sub-layer 1002 is 200 um - 400 um; the pore size of the first body connection sub-layer 1003 is 0 um - 200 um.

[0047] In this embodiment, the pore size of the above-mentioned first bone contact sub-layer 1001 gradually decreases from the outside (i.e., the side for bone contact) to the inside (such as the side in contact with the first support sub-layer) (such as Figure 4a the direction indicated by the arrow in ). For example, the pore size of the first bone contact sub-layer 1001 gradually decreases from 600 um to 400 um. Similarly, the pore size of the first support sub-layer 1002 also gradually decreases from the outside (such as the side in contact with the first bone contact sub-layer 1001) to the inside (such as the side in contact with the first body connection sub-layer 1003): that is, it decreases from between 400 um to 200 um; the pore size of the first body connection sub-layer 1003 also gradually decreases from the outside (such as the side in contact with the first support sub-layer 1002) to the inside (such as the side in contact with the solid tibial body): that is, it gradually decreases from 200 um to 0.

[0048] That is to say, based on mechanical analysis and functional requirements, this embodiment designs a first bone contact layer with a gradually decreasing pore size. Compared with a porous structure with the same pore size, a porous structure with a gradient region up to a solid substrate is closer to the mechanical properties of the human bone. At the same time, the porous structure provides a sufficient attachment surface for bone ingrowth, promotes bone ingrowth, and significantly improves the long-term stability and anti-loosening ability of the prosthesis.

[0049] Furthermore, the surface of the first bone contact layer 100 is polished so that its surface roughness reaches 0.05 um. The zirconium niobium alloy has good wear resistance, and its surface does not require an additional coating, which can achieve a very good wear-resistant effect. In this embodiment, a 1 - 3 mm porous structure bone contact layer is 3D printed, which can more effectively improve the bone ingrowth effect and is polished. This not only ensures the wear resistance of the joint surface but also ensures the biocompatibility of the bone bonding surface. Moreover, it can be integrally formed by 3D printing, and the solid and porous structures can be integrally formed, and its mechanical properties are better.

[0050] Refer to Figure 5a, the tibial fixation post 103 at least includes: a third bone contact layer 1031, an intermediate layer 1032, and a central layer 1033 that are stacked from outside to inside. Among them, the pore diameter of the third bone contact layer 1031 is 400um - 600um, the pore diameter of the intermediate layer 1032 is 200um - 400um; the pore diameter of the central layer 1033 is 0um - 200um; the pore diameter of the press-fit central cage 102 is 600um.

[0051] In this embodiment, the press-fit central cage adopts a cylindrical hollow structure, and a plurality of through holes are uniformly arranged along the circumferential direction on the side wall of the hollow structure. Such a design is beneficial to bone grafting and the growth of new bone tissue, thereby enhancing the connection strength between the tibial component and the tibia. It is also beneficial to retain bone mass, increase the bonding area with the tibia, and can also enhance stability, disperse stress, simplify the operation, and improve durability.

[0052] In this embodiment, a plurality of tibial fixation posts 103 are arranged around the press-fit central cage, and an annular groove is provided at its top. On the one hand, it is beneficial to optimize the stress distribution and protect the surrounding bone mass. On the other hand, it is beneficial to improve the initial stability and prevent the early detachment of the tibial component.

[0053] In some embodiments, the distance ratio between the press-fit central cage 102 and the front and rear sides of the first bone contact layer 100 is: 0.85 - 0.88 (preferably, the distance ratio is 0.87); and the distance ratio between the press-fit central cage (102) and the left and right sides of the first bone contact layer 100 is: 1.03 - 1.07 (preferably, the distance ratio is 1.06). That is, the press-fit central cage 102 is not located exactly in the center of the first bone contact layer 100.

[0054] See Figure 3 , in this embodiment, the talar prosthesis 30 further includes a locking clip formed by left and right side wings 104 that can cooperate with the first protrusions 201 on both sides of the liner 20; and a second protrusion 202 provided at the bottom and can cooperate with the upper surface of the liner 20. See Figure 1 and Figure 11 、 Figure 12 .

[0055] See Figure 6 , in this embodiment, the talar prosthesis 30 includes a talar body 301, a second bone contact layer 300 integrally formed on the talar body 301, and a plurality of talar fixation posts 302 provided on the second bone contact layer 300. Among them, both the second bone contact layer 300 and the talar fixation posts 302 are porous structures with gradually decreasing pore diameters from outside to inside.

[0056] Preferably, the porous second bone contact layer 300 is a multi-layer structure with a gradient-decreasing pore diameter, and the overall thickness is 1mm - 3mm. Specifically, see Figure 7aThe second bone contact layer 300 at least includes: a second bone contact sublayer 3001, a second supporting sublayer 3002 and a second body connecting sublayer 3003 stacked from the outside to the inside, wherein the pore size of the second bone contact sublayer 3001 is 400um-600um, the pore size of the second supporting sublayer 3002 is 200um-400um; the pore size of the second body connecting sublayer 3003 is 0um-200um.

[0057] In this embodiment, the aperture of the second bone contacting layer 300 is from the outside (i.e., the side for bone contact) to the inside (i.e., the side in contact with the second supporting sublayer) (i.e., Figure 7a The pore size of the second bone contact sublayer 3001 gradually decreases from 600um to 400um. Similarly, the pore size of the second support sublayer 3002 also gradually decreases from the outside (such as the side in contact with the second bone contact sublayer 3001) to the inside (such as the side in contact with the second body connection sublayer 3003): that is, it decreases from 400um to 200um; the pore size of the second body connection sublayer 3003 also gradually decreases from the outside (such as the side in contact with the second support sublayer 3002) to the inside (such as the side in contact with the solid talar body 301): that is, it gradually decreases from 200um to 0.

[0058] That is, based on mechanical analysis and functional requirements, this embodiment designs a second bone contact layer with a gradually decreasing pore size. Compared with a porous structure with the same pore size, a porous structure with a gradient area up to a solid base is closer to the mechanical properties of human bones. At the same time, the porous structure provides sufficient attachment surface for bone ingrowth, promotes bone ingrowth, and significantly improves the long-term stability and anti-loosening ability of the prosthesis.

[0059] Preferably, the overall shape of the talar prosthesis 30 is a curved talar prosthesis (such as Figure 6 ) or flat-cut talar prosthesis (eg Figure 8 ).

[0060] Among them, the curved talar prosthesis includes: a smooth bicondylar articular surface, the upper surface in contact with the substrate is printed with zirconium-niobium alloy and then polished to improve the wear resistance of the product, and its shape simulates the truncated cone shape of the ankle joint, aiming to reproduce the natural joint kinematics; the tapered shoulders on both sides are designed to reduce the impact with the fibula; the groove design in the middle can resist medial / lateral translation and subluxation; and the arc bottom, the overall bending fit, can retain the original good talus to the greatest extent, reduce bone loss, and the overall bending fits the talus to avoid the stress concentration problem of the three-plane bending design, enhance the fatigue resistance of the talar component, and at the same time make the talar component fit more closely with the talus, the force is more evenly applied, and the stability of the implant is increased. For some cases with large osteotomy and severe talar defects, a flat-cut talar prosthesis is used.

[0061] Since the porous structure provides space for the ingrowth of bone cells and promotes bone integration, but if the thickness is too small, there is insufficient space for bone cell ingrowth and the bone integration effect is poor; if the thickness is too large, it will increase the weight of the prosthesis, which may lead to stress shielding and a decrease in bone density; moreover, if the pore size is too small, it is difficult for bone cells to grow in, resulting in poor bone integration and unstable prosthesis structure. Therefore, in this embodiment, a porous structure with a thickness of 1-3 mm, a pore size of 200-600 microns, and a gradient-decreasing pore size design is proposed. It is closer to the mechanical properties of the human bone. On the one hand, it can reduce the elastic modulus of the prosthesis, making it closer to the mechanical properties of the human bone and reducing the stress shielding effect. On the other hand, it can significantly improve the long-term stability and anti-loosening ability of the prosthesis; moreover, the porous structure of this structure can more effectively promote bone integration and is most suitable for the ingrowth of bone cells and angiogenesis.

[0062] Embodiment 2: The present invention also provides another ankle joint prosthesis implantation system, which includes each component and structure in the above-mentioned Embodiment 1. The difference is that in this embodiment, further optimization is carried out according to the functional partition of the first bone contact layer and the second bone contact layer, so as to improve the mechanical properties of the porous structure, prevent shedding, and be more conducive to bone growth at the same time.

[0063] See Figure 9 , the first bone contact sub-layer 1001 includes a first reinforcement area 1001-1 surrounding the press-fit central cage 102 and the tibial fixing column 103, a first growth area 1001-2 respectively located on the front and back sides of the first reinforcement area 1001-1, and connection areas 1001-3 respectively located on the left and right sides of the first reinforcement area 1001-1 (that is, the connection areas provided on the wing 204).

[0064] Among them, the pore size of the first reinforcement area 1001-1 is larger than that of the first growth area 1001-2; the pore size of the first growth area 1001-3 is larger than that of the connection area 1001-3. For example, the pore size of the first reinforcement area 1001-1 is 600 um; the pore size of the first growth area 1001-3 is 590 um; the pore size of the connection area 1001-3 is 570 um.

[0065] More preferably, the porosity of the first reinforcement area 1001-1 is less than that of the first growth area 1001-2; the porosity of the first growth area 1001-3 is less than that of the connection area 1001-3. It is necessary to promote bone growth while ensuring the elastic modulus and mechanical properties of the prosthesis. Therefore, the larger the pore size area, the smaller its porosity. Preferably, the porosity of the first reinforcement area 1001-1 is 20%-23%, the porosity of the first growth area 1001-3 is 24%-26%, and the porosity of the connection area 1001-3 is 26%-30%.

[0066] SeeFigure 10 The second bone contact layer 300 includes a second reinforcement area 3001-1 surrounding the talus fixation post 302, and a second growth area 3001-2 surrounding the second reinforcement area 3001-1.

[0067] Among them, the pore size of the second reinforcement area 3001-1 is larger than that of the second growth area 3001-2. For example, the pore size of the second reinforcement area 3001-1 is 600um; the pore size of the second growth area 3001-2 is 550um.

[0068] Therefore, more preferably, in this embodiment, the porosity of the second reinforcement area 3001-1 is greater than that of the second growth area 3001-2. Similarly, the larger the pore size of a region, the smaller its porosity. Preferably, the porosity of the second reinforcement area 3001-1 is 20%-25%, and the porosity of the first growth area 1001-3 is 28%-30%.

[0069] Embodiment 3: The present invention also provides another ankle joint prosthesis implantation system, which includes the various components and structures in Embodiment 1 or Embodiment 2 above. The difference is that in this embodiment, the porosities of the first bone contact layer and the second bone contact layer are optimized. If the porosity is too high, the mechanical strength will decrease significantly, and the prosthesis is prone to fracture or deformation; if the porosity is too low, there is insufficient space for bone cells to grow in, and the bone integration effect is poor.

[0070] In this embodiment, the porosities of the first bone contact sub-layer 1001, the first support sub-layer 1002, and the first body connection sub-layer 1003 gradually increase, for example, they are respectively: 20%-30%, 30%-50%, 50%-70%. Also, the first bone contact sub-layer 1001 has the largest pore size and the lowest porosity. In this way, while facilitating bone growth, it can also improve compressive resistance, shear resistance, and wear resistance; the porosity of the first support sub-layer 1002 is relatively moderate to balance mechanical properties and biological activity; while the first body connection sub-layer 1003 has the smallest pore size but the largest porosity, thus ensuring mechanical properties.

[0071] In this embodiment, the porosities of the second bone contact sub-layer 3001, the second support sub-layer 3002, and the second body connection sub-layer 3003 gradually increase, for example, they are respectively: 10%-20%, 20%-40%, 40%-60%. Also, the second bone contact sub-layer 3001 has the largest pore size and the largest porosity. In this way, while facilitating bone growth, it can also improve compressive resistance, shear resistance, and wear resistance; the porosity of the second support sub-layer 3002 is relatively moderate to balance mechanical properties and biological activity; while the second body connection sub-layer 3003 has the smallest pore size but the largest porosity, thus ensuring mechanical properties.

[0072] Example 4: The present invention also provides another ankle joint prosthesis implantation system, which includes the components and structures of any one of the above Examples 1-3. The difference is that in this embodiment, cobalt-chromium-molybdenum is used for 3D printing to obtain the ankle joint prosthesis implantation system with the same structure as above. And a bone growth induction layer 40 with a thickness of 30um-150um is respectively provided on the first bone contact layer 100 of the tibial prosthesis 10 and the second bone contact layer 300 of the talar prosthesis 30. See Figure 4b and Figure 7b .

[0073] In this embodiment, cobalt-chromium-molybdenum is used to prepare the ankle joint prosthesis because, compared with titanium alloy, cobalt-chromium-molybdenum is more wear-resistant. However, when using the porous structure prepared by it as the fusion surface (such as the first bone contact layer 100 for contacting with bone), its bone ingrowth effect needs to be improved. Therefore, in this embodiment, a bone growth induction layer is respectively provided on the tibial prosthesis and the talar prosthesis prepared by cobalt-chromium-molybdenum to induce bone ingrowth.

[0074] Since the porosity of the first bone contact sub-layer 1001 is the largest, and a press-fit central cage 102 and tibial fixing posts 103 are provided in the first reinforcement area 1001-1 thereon to connect the tibia, that is, this area is a region where stress is relatively concentrated. Therefore, if a bone growth induction layer 40 (such as a hydroxyapatite coating) is provided, the bone growth induction layer in this area is more likely to be worn or the degree of wear is more serious compared with other areas. If the bone growth induction layer 40 is worn severely in the early stage, the formed bone-prosthesis interface may gradually degenerate, resulting in prosthesis loosening, and the worn particles may cause a series of problems such as foreign body reactions. Although a more durable ceramic coating or pure titanium coating can be used as the bone growth induction layer, its cost is too high, especially when coatings are required on both the tibial prosthesis and the talar prosthesis, which undoubtedly greatly increases the treatment cost for users. Therefore, to alleviate this problem, in this embodiment, hydroxyapatite with low cost is preferably used as the coating. For the first reinforcement area where stress is relatively concentrated, the hydroxyapatite coating thereon adopts a nano-composite coating (such as HA+TiO2) or a gradient coating (for example, a continuous transition of composition / structure is formed between the first reinforcement area and the hydroxyapatite coating, such as the surface of the first reinforcement area of cobalt-chromium-molybdenum → TiO2 transition layer → mixed layer of metal oxide (such as calcium phosphate) and HA → nano-HA layer) design to improve its wear resistance and the bonding strength between it and the first bone contact sub-layer. Similarly, the bone growth induction layer on the second reinforcement area 3001-1 of the second bone contact sub-layer 3001 also adopts a nano-composite coating or a gradient coating, while other areas adopt a pure HA coating. Of course, the bone growth induction layers on the first bone contact sub-layer and the second bone contact sub-layer can also all adopt nano-composite coatings (such as HA+TiO2) or gradient coatings, but this will result in a higher cost.

[0075] Further, referring to Figure 5b , in this embodiment, a bone growth induction layer 40 is also provided on the press-fit central cage 102, the tibial fixing post 103, and the talus fixing post 302. Further, in order to reduce the wear of the bone growth induction layer 40 on the press-fit central cage 102, the tibial fixing post 103, and the talus fixing post 302, the bone growth induction layer 40 on the press-fit central cage 102, the tibial fixing post 103, and the talus fixing post 302 adopts a nano-composite coating (such as HA + TiO2).

[0076] It should be noted that in this text, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including that element.

[0077] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the purpose of the present invention and the scope protected by the claims. All of these are within the protection scope of the present invention.

Claims

1. An ankle joint prosthesis implantation system based on a zirconium niobium alloy, comprising a tibial prosthesis (10), a talus prosthesis (30) and a liner (20), characterized in that, The tibial prosthesis (10) and the talar prosthesis (30) are both made of zirconium niobium alloy material and integrally formed by 3D printing. Among them, The tibial prosthesis (10) includes a tibial body (101) and a first bone contact layer (100) integrally formed on the tibial body (101). The first bone contact layer (100) is a porous structure with a gradually decreasing pore diameter from outside to inside. The first bone contact layer (100) at least includes: a first bone contact sub-layer (1001), a first support sub-layer (1002), and a first body connection sub-layer (1003) stacked from outside to inside. Among them, the pore diameter of the first bone contact sub-layer (1001) is 400um - 600um, the pore diameter of the first support sub-layer (1002) is 200um - 400um, and the pore diameter of the first body connection sub-layer (1003) is 0um - 200um. The talar prosthesis (30) includes a talar body (301) and a second bone contact layer (300) integrally formed on the talar body (301). The second bone contact layer (300) is a porous structure with a gradually decreasing pore diameter from outside to inside. The second bone contact layer (300) at least includes: a second bone contact sub-layer (3001), a second support sub-layer (3002), and a second body connection sub-layer (3003) stacked from outside to inside. Among them, the pore diameter of the second bone contact sub-layer (3001) is 400um - 600um, the pore diameter of the second support sub-layer (3002) is 200um - 400um, and the pore diameter of the second body connection sub-layer (3003) is 0um - 200um.

2. The ankle joint prosthesis implantation system based on a zirconium niobium alloy according to claim 1, wherein The thickness of the first bone contact layer (100) is 1 - 3mm; and / or, the thickness of the second bone contact layer (300) is 1 - 3mm.

3. The ankle joint prosthesis implantation system based on zirconium niobium alloy according to claim 1, characterized in that, The tibial prosthesis (10) further includes a press-fit central cage (102) provided on the first bone contact layer (100); both the press-fit central cage (102) and the tibial fixing post (103) are porous structures with a gradually decreasing pore diameter from outside to inside. Among them, The tibial fixing post (103) at least includes: a third bone contact layer (1031), an intermediate layer (1032), and a central layer (1033) stacked from outside to inside. Among them, the pore diameter of the third bone contact layer (1031) is 400um - 600um, the pore diameter of the intermediate layer (1032) is 200um - 400um, and the pore diameter of the central layer (1033) is 0um - 200um; and / or, the pore diameter of the press-fit central cage (102) is 600um.

4. The ankle joint prosthesis implantation system based on a zirconium niobium alloy according to claim 3, characterized in that, An annular groove is provided along the circumference at one end of the tibial fixing post (103) away from the first bone contact layer (100).

5. The ankle joint prosthesis implantation system based on zirconium niobium alloy according to claim 1, characterized in that, The talar prosthesis (30) further includes: a plurality of talar fixing posts (302) provided on the second bone contact layer (300). The talar fixing posts (302) are porous structures with a gradually decreasing pore diameter from outside to inside, and The talus fixing column (302) at least includes: a third bone contact layer (1031), an intermediate layer (1032), and a central layer (1033) that are stacked from outside to inside. Among them, the pore diameter of the third bone contact layer (1031) is 400um - 600um, the pore diameter of the intermediate layer (1032) is 200um - 400um; the pore diameter of the central layer (1033) is 0um - 200um.

6. The ankle joint prosthesis implantation system based on zirconium niobium alloy according to claim 5, characterized in that, The talus prosthesis (30) is a curved talus prosthesis or a flat-cut talus prosthesis.

7. The ankle joint prosthesis implantation system based on zirconium niobium alloy according to claim 3, characterized in that, The first bone contact sub-layer (1001) includes a first reinforcement area (1001-1) surrounding the press-fit central cage (102) and the tibia fixing column (103), a first growth area (1001-2) respectively located on the front and back sides of the first reinforcement area (1001-1), and connection areas (1001-3) respectively located on the left and right sides of the first reinforcement area (1001-1), where the pore diameter of the first reinforcement area (1001-1) is larger than the pore diameter of the first growth area (1001-2); the pore diameter of the first growth area (1001-3) is larger than the pore diameter of the connection area (1001-3); and the porosity of the first reinforcement area (1001-1) is greater than the porosity of the first growth area (1001-2); the porosity of the first growth area (1001-3) is greater than the porosity of the connection area (1001-3).

8. The ankle joint prosthesis implantation system based on zirconium niobium alloy according to claim 5, characterized in that The second bone contact layer (300) includes a second reinforcement area (3001-1) surrounding the talus fixing column (302), and a second growth area (3001-2) surrounding the second reinforcement area (3001-1); among them, the pore diameter of the second reinforcement area (3001-1) is larger than the pore diameter of the second growth area (3001-2); and the porosity of the second reinforcement area (3001-1) is greater than the porosity of the second growth area (3001-2).

9. The ankle joint prosthesis implantation system based on a zirconium niobium alloy according to claim 7, characterized in that, The porosities of the first bone contact sub-layer (1001), the first support sub-layer (1002), and the first body connection sub-layer (1003) are respectively: 20% - 30%, 30% - 50%, 50% - 70%.

10. The ankle joint prosthesis implantation system based on zirconium niobium alloy according to claim 8, characterized in that, The porosities of the second bone contact sub-layer (3001), the second support sub-layer (3002), and the second body connection sub-layer (3003) are respectively: 10% - 20%, 20% - 40%, 40% - 60%.

Images