Ankle joint talus prosthesis with antibacterial porous interface and its preparation method

Abstract

This invention belongs to the field of foot and ankle joint replacement implant technology, and discloses an ankle joint talus prosthesis with an antibacterial porous interface and its preparation method. It includes a prosthesis substrate with an overall anatomically contoured structure, including a superior articular surface, a inferior articular surface, and an anterior articular surface; the area of ​​the prosthesis substrate in contact with residual bone tissue is designed as a three-dimensional porous structure; an antibacterial bioactive composite coating is grown in situ on the surface of the prosthesis substrate; it includes calcium and phosphorus bioactive components and antibacterial ions. This invention, by constructing an antibacterial bioactive composite coating at a porous bone integration interface, utilizes biocompatibility and osteoconductivity to induce bone tissue growth. Furthermore, the antibacterial ions can be slowly and continuously released in the interstitial spaces, achieving a dual function of promoting bone integration and preventing infection. Moreover, the antibacterial bioactive composite coating is formed through in-situ growth, resulting in a strong bond with the substrate and preventing detachment.

Description

Technical Field

[0001] This invention relates to the field of foot and ankle joint replacement implant technology, and in particular to an ankle joint talus prosthesis with an antibacterial porous interface and its preparation method. Background Technology

[0002] The talus plays a crucial role in weight-bearing and movement within the ankle and subtalar joints, but its blood supply is relatively limited, making it highly susceptible to structural collapse after severe trauma, infection, or ischemic necrosis. For patients with severe talar necrosis or defects, total talar prosthesis replacement has become an important limb-sparing treatment.

[0003] Current talus prostheses mostly employ dense metal structures or simple porous designs. While these provide some mechanical support or space for bone ingrowth, there is still a risk of infection in the early stages of implantation. This is especially true in patients with traumatic necrosis, post-infection reconstruction, or a history of multiple surgeries, where local soft tissue conditions are poor, significantly increasing the risk of bacterial adhesion and biofilm formation around the implant. Once infection occurs, it will severely affect the stability of the prosthesis and may even lead to reoperation or amputation.

[0004] Traditional antibacterial strategies often rely on intraoperative antibiotics or local release of bone cement, which have limited duration and are difficult to form a stable antibacterial interface on the surface of metal prostheses.

[0005] Therefore, how to construct a bioactive interface on the surface of the talus prosthesis that combines osteointegration and antibacterial functions has become a key technical issue for improving the long-term stability of the prosthesis. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a three-dimensional porous talus prosthesis with an antibacterial porous interface. By constructing a composite coating containing calcium and phosphorus bioactive components and antibacterial ions at the porous osteointegration interface, a synergistic effect of promoting osteointegration and preventing infection is achieved, thereby improving the long-term stability and safety of the prosthesis after implantation.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: providing an ankle joint talus prosthesis with an antibacterial porous interface, comprising,

[0008] The prosthesis matrix is ​​an anatomically contoured structure, including the superior articular surface, the inferior articular surface, and the anterior articular surface; the area of ​​the prosthesis matrix in contact with the residual bone tissue is designed as a three-dimensional porous structure. An antibacterial bioactive composite coating is grown in situ on the surface of the prosthesis substrate; it includes calcium and phosphorus bioactive components and antibacterial ions.

[0009] According to the present invention, the three-dimensional porous structure further adopts a regular lattice structure or a random trabecular biomimetic structure, with a porosity of 55% to 85% and a pore size of 300 to 1000 micrometers, and the pores are interconnected.

[0010] According to the present invention, the prosthesis substrate material is further defined as titanium or a titanium alloy.

[0011] According to the present invention, the calcium phosphate component is further comprising hydroxyapatite or calcium phosphate compounds.

[0012] According to the present invention, the calcium content in the calcium-phosphorus component is 6% to 12% atomic percentage and the phosphorus content is 3% to 7% atomic percentage.

[0013] According to the present invention, the antibacterial ion is further selected from one or more of zinc ions, copper ions or silver ions.

[0014] According to the present invention, the antibacterial ion is further described as a composite system of zinc ions and silver ions.

[0015] According to the present invention, the antibacterial ion is silver ion, and the silver ion source exists in the interstitial space of the crystal structure of hydroxyapatite in the form of nanoclusters or lattice substitution.

[0016] According to the present invention, the antibacterial bioactive composite coating has a thickness of 2 to 8 micrometers and a micrometer-scale pore structure on its surface. The pore sizes are distributed in a gradient, with the pore size near the interface of the prosthesis substrate being larger than that near the outer surface.

[0017] In another aspect, the present invention also provides a method for preparing a three-dimensional porous talus prosthesis with an antibacterial porous interface, comprising the following steps: Step 1: 3D Modeling A three-dimensional model of the talus is established based on the patient's ankle joint CT or MRI image data, and a porous bone integration structure is constructed. Step 2: 3D printing The talus prosthesis is printed in one piece using metal additive manufacturing technology, with titanium or titanium alloy powder as the printing material. Step 3: Surface activation treatment The porous surface of the prosthesis is cleaned and chemically activated to improve the bonding strength of subsequent coatings; Step 4: Micro-arc oxidation treatment Micro-arc oxidation treatment is performed on the porous structure surface to form a porous oxide layer containing calcium and phosphorus elements. Step 5: Hydrothermal Treatment The prosthesis treated with micro-arc oxidation was placed in a hydrothermal reaction system containing antibacterial ions, and a bioactive composite coating containing antibacterial ions was generated in situ on the surface of the porous oxide layer. Step 6: Cleaning and Sterilization The processed prosthesis is then subjected to ultrasonic cleaning, drying, and sterilization to obtain the final product.

[0018] The beneficial effects of this invention are as follows: This invention constructs an antibacterial bioactive composite coating at a porous osteointegration interface. Utilizing biocompatibility and osteoconductivity, it induces bone tissue growth. Furthermore, antibacterial ions are slowly and continuously released within the intercrystalline lattice, achieving a dual function of promoting osteointegration and preventing infection. Moreover, the antibacterial bioactive composite coating is formed through in-situ growth, resulting in a strong bond with the substrate and preventing detachment.

[0019] The antibacterial bioactive composite coating of the present invention forms micropores on its surface, and antibacterial ions can be continuously released in the early stage of implantation, effectively inhibiting bacterial adhesion and biofilm formation.

[0020] The three-dimensional porous structure of this invention provides a three-dimensional scaffold for bone tissue ingrowth, thereby improving the biological fixation ability of the prosthesis.

[0021] This invention can be combined with personalized 3D printing technology to improve anatomical matching and clinical applicability. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the ankle joint talus prosthesis with an antibacterial porous interface according to the present invention; Figure 2 for Figure 1 A magnified view of a portion of the image. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0024] This application discloses an ankle talus prosthesis with an antibacterial porous interface. The talus prosthesis is modeled individually based on the patient's CT or MRI image data, and includes a prosthesis substrate and an antibacterial bioactive composite coating produced in situ on its surface through a micro-arc oxidation process. For example... Figure 1 and Figure 2 As shown, the talus prosthesis has an anatomically contoured structure, including a superior articular surface, a inferior articular surface, and an anterior articular surface. The articular surfaces are sandblasted to create an activated surface with a roughness of Ra 2.8-5.6 μm. The area where the talus prosthesis contacts residual bone tissue is designed as a three-dimensional porous structure. This three-dimensional porous structure employs a regular lattice structure or a random trabecular bone structure, with a porosity of 55% to 85% and a pore size of 300 to 1000 micrometers. The pores are interconnected to promote bone ingrowth. The prosthesis matrix material is titanium or a titanium alloy.

[0025] An antibacterial bioactive composite coating is grown in situ on the surface of a three-dimensional porous structure, comprising calcium-phosphorus bioactive components and antibacterial ions. The calcium-phosphorus component is hydroxyapatite or calcium phosphate compounds, preferably with a calcium content of 6% to 12% atomic percentage and a phosphorus content of 3% to 7% atomic percentage; the antibacterial ions are selected from one or more of zinc ions, copper ions, or silver ions. Optionally, the antibacterial ions are a composite system of zinc ions and silver ions; preferably, the antibacterial ions are silver ions, with the silver ion source existing in the interstitial spaces of the hydroxyapatite crystal structure in the form of nanoclusters or lattice substitution.

[0026] Furthermore, the antibacterial bioactive composite coating has a thickness of 2 to 8 micrometers and a surface with a micrometer-scale pore structure, which can continuously release antibacterial ions in the early stages of implantation to inhibit bacterial adhesion and biofilm formation. Preferably, the micropore size is gradient-distributed, with the pore size near the interface of the prosthesis substrate being larger than that near the outer surface.

[0027] The present invention also provides a method for preparing the above-mentioned three-dimensional porous talus prosthesis with an antibacterial porous interface, comprising the following steps: Step 1: 3D Modeling A three-dimensional model of the talus was created based on the patient's ankle CT or MRI imaging data: CT data (slice thickness ≤ 0.625 mm) was imported into Mimics (Materialise Corp., Leuven, Belgium) or 3D Slicer software, and the bone contour was extracted by threshold segmentation (226–3071 HU) to generate a three-dimensional model of the talus; anatomical contour structures were constructed using mirroring technology (with the healthy talus as a reference) or reverse repair technology based on bone defect areas; a three-dimensional porous bone integration structure was constructed in the area in contact with residual bone tissue, using Gyroid, Schwartz Diamond, or body-centered cubic (BCC) lattice structures, and a gradient porous region with a porosity of 55%–75% and a pore size of 300–600 μm was designed; the stress distribution under compressive load (approximately 2–3 times body weight for daily adult talus load) was simulated using finite element analysis (COMSOL Multiphysics or Ansys), and the porous structure parameters were optimized to ensure the elastic modulus (0.28–30). The slice thickness (GPa) is matched with human cancellous bone; the final output is an STL format file with a slice thickness set to 0.025–0.04 mm. Step 2: 3D printing The talus prosthesis is printed in one piece using metal additive manufacturing technology: Printing was performed using Ti6Al4V powder (particle size 15–45 μm, oxygen content <0.1%) under inert gas protection (argon, oxygen content <0.05%). Process parameters: laser power 160–340 W, scanning speed 900–1750 mm / s, scanning spacing 40–120 μm, powder layer thickness 25–40 μm, laser spot diameter 50–70 μm; interlayer rotation scanning strategy was adopted (rotation angle 60°–67°), substrate preheating temperature 200°C; after printing, heat treatment was performed (annealing: 750°C, 4 hours, argon atmosphere, heating rate 5°C / min) to eliminate residual stress. After printing, the support structure is removed, and the paper is ultrasonically cleaned for 15 minutes each with acetone and anhydrous ethanol to remove residual powder. Step 3: Surface activation treatment The porous surface of the prosthesis was cleaned and chemically activated: it was ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15 minutes each in sequence; then it was sandblasted (alumina abrasive particles, particle size 65–105 μm, pressure 1.5 bar, working distance 15 cm) to achieve a surface roughness of Ra 1.5–3.5 μm to improve the bonding strength of subsequent coatings. Step 4: Micro-arc oxidation treatment Micro-arc oxidation treatment is performed on porous surfaces using an alkaline electrolyte system containing 0.17 mol / L NaOH and 0.016 mol / L zinc acetate (Zn(CH3COO)2·2H2O), or a calcium-phosphorus electrolyte (such as calcium acetate and β-glycerophosphate). The process parameters are: voltage 300–450 V, current density 180–250 mA / cm², pulse frequency 300–1000 Hz, treatment time 5–10 minutes, and temperature controlled at 23–25°C. After treatment, a porous oxide layer containing calcium and phosphorus elements is formed on the surface, with a pore diameter of 0.15–15 μm, a coating thickness of 2.5–7 μm, and a bonding strength of up to 45±5 MPa. Step 5: Hydrothermal Treatment The prosthesis treated with micro-arc oxidation was placed in a hydrothermal reaction system containing antibacterial ions: a Ca-P solution (such as a mixed solution of Ca(OH)2 or Ca(HCOO)2 and Na2HPO4) was used, and a silver ion source (such as silver nitrate, concentration 10–30 g / L) or a copper ion source was added; the pH value was adjusted to 8.0–11.5, and hydrothermal treatment was carried out in a pressure reactor at a temperature of 160–200°C for 5–12 hours; a nano-hydroxyapatite composite coating containing antibacterial ions was generated in situ on the surface of the porous oxide layer, with a coating thickness of about 4–8 μm, and nanoscale plate-like or needle-like HA crystals were formed on the surface; Step 6: Cleaning and Sterilization The processed prosthesis is then subjected to ultrasonic cleaning, drying, and sterilization to obtain the final product.

[0028] Example 1 Take a case of talus necrosis as an example: The preparation method of the ankle joint talus prosthesis with antibacterial porous interface is as follows: (1) Reconstruct a three-dimensional model of the talus based on the patient's CT data and construct an anatomical contour structure, including the superior articular surface, the inferior articular surface and the anterior articular surface; (2) The prosthesis matrix is ​​made of Ti6Al4V titanium alloy and is integrally formed by selective laser melting (SLM); (3) A three-dimensional porous structure was constructed in the contact area with bone tissue, with a porosity of 70% and an average pore size of 600 μm, using a Gyroid structure; (4) The joint surfaces are sandblasted to a surface roughness of Ra 3.5μm; (5) Micro-arc oxidation treatment is performed on the porous surface, and the electrolyte contains calcium source, phosphorus source and silver nitrate (20 g / L). (6) Zinc acetate (20 g / L) is introduced during the micro-arc oxidation process to form ZnO nanocrystals; (7) Perform hydrothermal treatment (150℃, 10h) to form a hydroxyapatite composite coating on the surface; (8) Finally, an antibacterial bioactive composite coating with a thickness of about 4 μm was obtained.

[0029] Example 2 Based on Example 1, the Ag+ content is 10g / L and the ZnO gradient is low, forming a low antibacterial bioactive composite coating. The Ag+ provides continuous antibacterial protection, and the low ZnO gradient allows the antibacterial bioactive composite coating to maintain a certain bonding strength with the bone interface, making it suitable for short-term implantation scenarios with moderate antibacterial requirements.

[0030] Example 3 Based on Example 1, the Ag+ content is 30 g / L, and the ZnO gradient is low, forming a composite coating with strong antibacterial bioactivity. The low ZnO gradient avoids stress concentration at the bone interface, while the high Ag+ content can effectively reduce the bone cell proliferation rate, making it suitable for scenarios with high infection risk that require strong antibacterial effects.

[0031] Example 4 Based on Example 1, the Ag+ content is 20 g / L, the ZnO gradient is high, and a piezoelectric difference is formed along the thickness direction. Under cyclic loading, the electrorepulsion effect on bacterial adhesion is strong, so that the antibacterial bioactive composite coating has both antibacterial and piezoelectric bone integration promotion functions.

[0032] Example 5 Based on Example 1, with an Ag+ content of 20 g / L, a moderate ZnO gradient, and 3% Sr doping, an antibacterial bioactive composite coating that can achieve osteogenic enhancement is formed, suitable for the repair of osteoporotic bone defects.

[0033] Example 6 Based on Example 1, the Ag+ content was 20 g / L, the ZnO gradient was moderate, and 3% magnesium (Mg) was doped to accelerate early bone differentiation. At the same time, the slightly alkaline environment of magnesium ions could prolong the bactericidal time of Ag+, providing a stable antibacterial and adhesion-promoting microenvironment for the early stage of bone regeneration.

[0034] This talus prosthesis features a partitioned design of the motion interface and the bone integration interface. While ensuring joint motion performance, it provides an antibacterial bioactive interface in the bone contact area, which can inhibit bacterial colonization in the early stage of implantation and promote bone tissue growth into the porous structure in the middle and late stages, thus achieving stable biological fixation.

[0035] This invention is particularly suitable for complex cases requiring talus replacement, such as severe talus necrosis or reconstruction after tumor resection, and can significantly reduce the risk of infection and loosening.

[0036] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. Ankle joint talus prosthesis with an antibacterial porous interface, characterized in that, include, The prosthesis matrix is ​​an anatomically contoured structure, including the superior articular surface, the inferior articular surface, and the anterior articular surface; the area of ​​the prosthesis matrix in contact with the residual bone tissue is designed as a three-dimensional porous structure. An antibacterial bioactive composite coating is grown in situ on the surface of the prosthesis substrate; It includes calcium and phosphorus bioactive components and antibacterial ions.

2. The ankle joint talus prosthesis with an antibacterial porous interface as described in claim 1, characterized in that, The three-dimensional porous structure adopts a regular lattice structure or a random trabecular biomimetic structure, with a porosity of 55% to 85% and a pore size of 300 to 1000 micrometers, and the pores are interconnected.

3. The ankle joint talus prosthesis with an antibacterial porous interface as described in claim 1, characterized in that, The prosthesis substrate material is titanium or titanium alloy.

4. The ankle joint talus prosthesis with an antibacterial porous interface as described in claim 1, characterized in that, The calcium phosphate component is hydroxyapatite or calcium phosphate compounds.

5. The ankle joint talus prosthesis with an antibacterial porous interface as described in claim 4, characterized in that, The calcium-phosphorus component contains 6% to 12% calcium and 3% phosphorus by atomic percentage.

6. The ankle joint talus prosthesis with an antibacterial porous interface as described in claim 1, characterized in that, The antibacterial ions are selected from one or more of zinc ions, copper ions, or silver ions.

7. The ankle joint talus prosthesis with an antibacterial porous interface as described in claim 6, characterized in that, The antibacterial ions are a composite system of zinc and silver ions.

8. The ankle joint talus prosthesis with an antibacterial porous interface as described in claim 4, characterized in that, The antibacterial ion is a silver ion, and the silver ion source exists in the interstitial space of the hydroxyapatite crystal structure in the form of nanoclusters or lattice substitution.

9. The ankle joint talus prosthesis with an antibacterial porous interface as described in claim 1, characterized in that, The antibacterial bioactive composite coating has a thickness of 2 to 8 micrometers and a micrometer-level pore structure on its surface. The pore size is gradient-distributed, with the pore size near the interface of the prosthesis substrate being larger than that near the outer surface.

10. A method for preparing a three-dimensional porous talus prosthesis with an antibacterial porous interface, characterized in that, Includes the following steps: Step 1: 3D Modeling A three-dimensional model of the talus was established based on the patient's ankle joint imaging data, and a porous bone integration structure was constructed. Step 2: 3D printing The talus prosthesis is printed in one piece using metal additive manufacturing technology, with titanium or titanium alloy powder as the printing material. Step 3: Surface activation treatment The porous surface of the prosthesis is cleaned and chemically activated to improve the bonding strength of subsequent coatings; Step 4: Micro-arc oxidation treatment Micro-arc oxidation treatment is performed on the porous structure surface to form a porous oxide layer containing calcium and phosphorus elements. Step 5: Hydrothermal Treatment The prosthesis treated with micro-arc oxidation was placed in a hydrothermal reaction system containing antibacterial ions, and a bioactive composite coating containing antibacterial ions was generated in situ on the surface of the porous oxide layer. Step 6: Cleaning and Sterilization The processed prosthesis is then subjected to ultrasonic cleaning, drying, and sterilization to obtain the final product.

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