Radial gradient porous structure with complete lattice interface, preparation method and application

Abstract

The present application relates to a kind of radial gradient porous structure with complete lattice interface, preparation method and application, and the porous structure includes: several layers of ring layer, the size of lattice unit in the same ring layer is equal and lattice morphology is same, and the stress distribution of porous structure is uniform in local range;Several layers of ring layer are connected in turn along radial direction, and the size of lattice unit in ring layer increases in turn from central axis to outside along radial direction, and form radial gradient;The lattice unit of adjacent ring layer is connected one by one, and the adjacent arc length of two lattice units of corresponding connection is equal;It is guaranteed that porous structure has good structural strength simultaneously.By setting the size of each lattice unit reasonably, the porous structure has complete lattice interface, and the lattice unit on porous interface is all complete lattice unit, and the stress conduction of porous structure surface is optimized.Porous structure is prepared by 3D printing additive, and the preparation method is convenient and reliable, and can adapt to the preparation requirement of different parameter porous structure.

Description

Technical Field

[0001] This invention belongs to the field of medical implant technology, specifically relating to a radial gradient porous structure with a complete lattice interface, its preparation method, and its application. Background Technology

[0002] With the rapid development of 3D printing technology, a large number of implants with porous structures have emerged to reduce the elastic modulus of metal implants. These implants achieve their porous structures by arranging individual lattice units in a rectangular array and using Boolean operations to cut the filled area. This porous structure has high overall porosity to reduce the elastic modulus of the implant and provide space for bone cell growth. However, the lattice units on the product surface form incomplete lattice interfaces after being cut, preventing the unit rods on the porous structure surface from connecting to a common node. This results in numerous isolated unit rods on the porous structure surface, affecting stress transmission and reducing the strength of the porous implant. Furthermore, porous structures with incomplete lattice interfaces are prone to breakage and detachment under external forces after implantation. These broken and detached unit rods remaining in the body can have adverse effects.

[0003] CN 116059012A discloses a multidimensional spatial gradient porous minimal curved surface bone implant material and its design method. In this scheme, the diameter of the unit rods is adjusted in three-dimensional space to form a mesh-like porous structure array with different internal pore shapes and sizes, thus changing the density of the porous structure. However, in this scheme, the porous structure density is adjusted by changing the diameter of the unit rods. In some local regions, the inconsistent diameters of the unit rods lead to uneven stress distribution in those regions. Therefore, it is necessary to prepare a porous structure with a complete lattice interface that balances stress distribution and structural strength. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a radially gradient porous structure with a complete lattice interface, its preparation method, and its application. The technical problem to be solved by this invention is achieved through the following technical solution:

[0005] This invention provides a radially gradient porous structure with a complete lattice interface, comprising: several ring layers;

[0006] The plurality of ring layers are arranged radially along the same central axis, and the plurality of ring layers are connected sequentially from the innermost ring layer closest to the central axis to the outermost ring layer farthest from the central axis.

[0007] The ring layer includes a plurality of lattice units, which are arranged in a ring array and connected sequentially.

[0008] The lattice units in the same ring layer are all of equal size, and the lattice morphology of the lattice units in the same ring layer is all the same.

[0009] The size of the lattice units in the several ring layers increases radially outward from the central axis, forming a radial gradient;

[0010] The lattice units of adjacent ring layers are connected in a one-to-one correspondence, and the adjacent arc lengths of two correspondingly connected lattice units are equal;

[0011] The radial lengths of the lattice units in the plurality of ring layers are all equal;

[0012] The diameters of the unit rods of the lattice units in the plurality of ring layers are all equal;

[0013] The outermost ring layer of the porous structure is a lattice interface, and the lattice units in the lattice interface are all complete lattice units.

[0014] In one embodiment of the present invention, the porous structure is a geometric body with a symmetrical central axis, including: a cylinder, a sphere, a cylindrical shell, or a spherical shell.

[0015] In one embodiment of the present invention, the lattice morphology of the lattice unit includes: diamond unit, face-centered cubic unit, body-centered cubic unit, or honeycomb unit.

[0016] This invention provides a method for preparing a radially gradient porous structure with a complete lattice interface, comprising:

[0017] Step 1: Based on the implantation requirements of the porous structure at the implantation site, obtain the actual geometric shape of the porous structure and the geometric shape of the annular layer structure of the porous structure.

[0018] Step 2: Based on the geometric shape of the ring-layer structure of the porous structure, determine the ring-layer structure of the porous structure to obtain a model of the radially gradient porous structure;

[0019] Step 3: Based on the actual geometric shape of the porous structure, perform a lattice array on the model of the radial gradient porous structure to obtain a preliminary model of the radial gradient porous structure with a complete lattice interface.

[0020] Step 4: Verify the overall porosity and lattice interface porosity of the preliminary model of the radial gradient porous structure with complete lattice interface. If the implantation requirements are met, the final model of the radial gradient porous structure with complete lattice interface is obtained. If the implantation requirements are not met, repeat steps 2 to 3 until both the overall porosity and lattice interface porosity meet the implantation requirements, and the final model of the radial gradient porous structure with complete lattice interface is obtained.

[0021] Step 5: Based on the final model of the radial gradient porous structure with complete lattice interface, the radial gradient porous structure with complete lattice interface is prepared by 3D printing.

[0022] In one embodiment of the present invention, step 2 includes:

[0023] Step 2.1: Determine the size, lattice morphology, and porosity of the lattice units located at the lattice interface according to the implantation requirements;

[0024] Step 2.2: Determine the ring structure of the porous structure based on the geometric shape of the ring structure, the porosity of the lattice interface, the size and lattice morphology of the lattice units located at the lattice interface, including: the number of ring layers and the number of lattice units in each ring layer.

[0025] Step 2.3: Based on the ring structure of the porous structure, connect several lattice units and ring layers together in sequence to obtain a model of a radially gradient porous structure.

[0026] In one embodiment of the present invention, step 2.3 includes:

[0027] Step 2.3.1: Based on the number of lattice units in each ring layer, calculate the rotation angle θ of each lattice unit. The formula for calculating the rotation angle θ is:

[0028]

[0029] Where L is the arc length of the lattice unit cell in the ring layer along the radial direction away from the central axis; L n-1 Let θ be the arc length of the lattice unit in the (n-1)th ring layer along the radial direction away from the central axis; θ be the rotation angle of the lattice unit; and R be the radial length of the lattice unit.

[0030] Step 2.3.2: Deform the lattice unit according to the rotation angle θ to obtain the deformed lattice unit;

[0031] Step 2.3.3: Connect the deformed lattice units together in sequence to obtain a model of a porous structure with radial gradient.

[0032] This invention provides an application of a radially gradient porous structure with a complete lattice interface in implants.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] The present invention relates to a radially gradient porous structure with a complete lattice interface. The high porosity of the porous structure surface is conducive to bone cell adhesion and growth, while the low porosity inside the porous structure enhances its strength. Several lattice units are arranged in a ring array and connected sequentially to form several ring layers. The lattice units in the same ring layer are of equal size, the diameter of the unit rods is equal, and the lattice morphology is the same, resulting in uniform stress distribution in the local area of ​​the porous structure. The several ring layers are connected sequentially along the radial direction, and the size of the lattice units in the ring layer increases radially outward to form a radial gradient, which improves the structural strength of the porous structure. By reasonably setting the size of each lattice unit, the porous structure has a complete lattice interface, and the lattice units in the lattice interface are all complete lattice units, thus optimizing the stress distribution of the porous structure.

[0035] This invention discloses a method for fabricating a radially gradient porous structure with a complete lattice interface. The porous structure is prepared according to the implantation requirements of the implantation site. A ring layer and its constituent lattice units are designed inwards from the lattice units at the lattice interface. The size of the lattice units in the ring layer increases radially outwards to form a radial gradient. The overall porosity of the porous structure and the porosity of the lattice interface are used as verification criteria to ensure that the porous structure possesses both a complete lattice surface and good structural strength. Finally, the porous structure is fabricated using 3D printing additive manufacturing. This method is convenient, reliable, and adaptable to the fabrication requirements of various porous structures.

[0036] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention;

[0038] Figure 2 This is a partial structural schematic diagram of a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the structure of a lattice unit with a radial gradient porous structure having a complete lattice interface, provided in an embodiment of the present invention.

[0040] Figure 4 This is a flowchart of a method for preparing a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention;

[0041] Figure 5 This is a flowchart of step 2 of a method for preparing a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention;

[0042] Figure 6 This is a flowchart of step 2.3 of a method for preparing a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention.

[0043] Figure 7 This is a schematic diagram of a porous cylindrical implant provided in an embodiment of the present invention;

[0044] Figure 8 It is a finite element analysis diagram of a porous structure of a cylinder using a common rectangular array Boolean operation;

[0045] Figure 9 This is a finite element analysis diagram of a radial gradient porous structure of a cylinder with a complete lattice interface provided in an embodiment of the present invention;

[0046] Figure 10 This is a schematic diagram of the porous structure of the double cylinder provided in an embodiment of the present invention;

[0047] Figure 11 This is a schematic diagram of the porous structure implant with dual cylinders provided in an embodiment of the present invention;

[0048] Figure 12 This is a front view of the porous structure of the spherical shell provided in an embodiment of the present invention;

[0049] Figure 13 This is a top view of the porous structure of the spherical shell provided in an embodiment of the present invention. Detailed Implementation

[0050] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following, in conjunction with the accompanying drawings and specific embodiments, provides a detailed description of a radial gradient porous structure with a complete lattice interface, its preparation method, and its application based on the present invention.

[0051] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0052] Example 1

[0053] Please refer to the above. Figure 1 , Figure 2 and Figure 3 , Figure 1 This is a schematic diagram of a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention; Figure 2 This is a partial structural schematic diagram of a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a lattice unit with a complete lattice interface and a radial gradient porous structure provided in an embodiment of the present invention.

[0054] As shown in the figure, the radial gradient porous structure with a complete lattice interface of the present invention includes: several ring layers;

[0055] Among them, several ring layers are arranged radially along the central axis, and the ring layers are connected sequentially from the innermost ring layer closest to the central axis to the outermost ring layer farthest from the central axis; each ring layer includes several lattice units, which are arranged in a ring array and connected sequentially.

[0056] It is worth noting that the high porosity on the surface of the porous structure is conducive to the adhesion and growth of osteoblasts, while the low porosity inside the porous structure enhances the strength of the porous structure; the unit rods of individual lattice units have the same diameter, and the stress transmission on the common nodes connecting the unit rods is more uniform.

[0057] In this embodiment, the lattice units in the same ring layer are all of equal size, and the lattice morphology of the lattice units in the same ring layer is all the same. The equal size of the lattice units ensures that the stress distribution in the local area of ​​the porous structure is uniform, and the same lattice morphology also ensures that the stress distribution in the local area is uniform, while also facilitating the connection between the lattice units.

[0058] In this embodiment, the size of the lattice units in several ring layers increases radially outward from the central axis, forming a radial gradient. This radial gradient manifests as a change in the porosity of the porous structure; that is, the porosity is small inside the porous structure and large outside. The small internal porosity ensures the structural strength of the central location, which is the main load-bearing part of the porous structure. The large external porosity maximizes the promotion of osteoblast adhesion and growth. Furthermore, the large external porosity provides the largest possible space for osteoblast ingrowth.

[0059] In one optional implementation, the lattice units of adjacent ring layers are connected one-to-one, and the lattice units in several ring layers are connected sequentially to form a fan-shaped structure, with the adjacent arc lengths of two correspondingly connected lattice units being equal.

[0060] In this embodiment, the outermost ring layer of the porous structure is a lattice interface. The lattice units in the lattice interface are all complete lattice units. The complete lattice interface makes the surface of the porous structure smooth and without sharp edges, which is conducive to stress transmission in the porous structure and promotes bone cell growth.

[0061] In one optional embodiment, the radial lengths of the lattice units in the several ring layers are all equal, and the diameters of the unit rods of the lattice units in the several ring layers are all equal, so as to facilitate the connection of the lattice units and facilitate the formation of a complete lattice interface.

[0062] In one alternative embodiment, the porous structure is a geometry with a symmetrical central axis, including: a cylinder, a sphere, a cylindrical shell, or a spherical shell.

[0063] In one alternative implementation, the geometry of the porous structure is determined based on the implantation location and implantation requirements.

[0064] In one optional embodiment, the pore size of the lattice unit ranges from 400 to 700 μm, and the diameter of the unit rod of the lattice unit ranges from 200 to 500 μm. The size distribution of the lattice unit within this range ensures that the porous structure has excellent structural strength and promotes bone growth.

[0065] In one alternative implementation, the lattice morphology of the crystal unit includes: diamond unit, face-centered cubic unit, body-centered cubic unit, or honeycomb unit.

[0066] In one optional embodiment, the lattice morphology of the crystal unit is diamond unit. The diamond unit structure has good stability and is a biomimetic bone trabecular structure. The connection nodes between the crystal units are smooth and the pores are interconnected, which is conducive to the migration and proliferation of bone cells.

[0067] In an optional implementation, the closer the porosity of the lattice interface is to that of human cancellous bone, the more favorable it is for bone growth. Therefore, the porosity range of the lattice interface is set to 70% to 90%.

[0068] It is worth noting that the overall porosity of the porous structure varies in the range of 30% to 80%, while the porosity of the lattice interface varies in the range of 70% to 90%. The porosity of the lattice unit in the porous structure gradually increases radially from the inside to the outside. Specifically, the diameter of the unit rod of the lattice unit remains unchanged, while the pore size of a single lattice unit gradually increases radially from the inside to the outside.

[0069] The present invention provides a radial gradient porous structure with a complete lattice interface. The high porosity of the porous structure surface is conducive to bone cell adhesion and growth, while the low porosity inside the porous structure enhances its strength. Several lattice units are arranged in a ring array and connected sequentially to form several ring layers. The lattice units in the same ring layer are of equal size, the diameter of the unit rods is equal, and the lattice morphology is the same, resulting in uniform stress distribution in the local area of ​​the porous structure. The several ring layers are connected sequentially along the radial direction, and the size of the lattice units in the ring layer increases radially outward to form a radial gradient, which improves the structural strength of the porous structure. By reasonably setting the size of each lattice unit, the porous structure has a complete lattice interface, and the lattice units in the lattice interface are all complete lattice units, thus optimizing the stress distribution of the porous structure.

[0070] Example 2

[0071] Please see Figure 4 , Figure 4 This is a flowchart of a method for preparing a radial gradient porous structure with a complete lattice interface, provided by an embodiment of the present invention.

[0072] As shown in the figure, the method for preparing a radially gradient porous structure with a complete lattice interface according to the present invention is used to prepare the radially gradient porous structure with a complete lattice interface as described in any one of claims 1 to 6, comprising:

[0073] Step 1: Based on the implantation requirements of the porous structure at the implantation site, obtain the actual geometric shape of the porous structure and the geometric shape of the annular layer structure of the porous structure.

[0074] It is worth noting that, due to the complexity of the implantation site, the shape of the porous structure is not always regular according to the actual requirements. Therefore, after forming the geometric shape of the ring structure, it is necessary to select the lattice units to meet the requirements of its shape and size. Some lattice units will be screened out as a whole to generate a porous structure.

[0075] Step 2: Based on the geometric shape of the porous structure's ring layer structure, determine the ring layer structure of the porous structure to obtain a model of the porous structure with radial gradient;

[0076] Please see Figure 5 , Figure 5 This is a flowchart of step 2 of a method for preparing a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention.

[0077] As shown in the figure, step 2 includes:

[0078] Step 2.1: Determine the size, lattice morphology, and porosity of the lattice units located at the lattice interface according to the implantation requirements;

[0079] In one alternative implementation, the lattice morphology of the crystal unit includes: diamond unit, face-centered cubic unit, body-centered cubic unit, or honeycomb unit.

[0080] In one optional embodiment, the aperture range of the lattice unit is 400–700 μm, the diameter range of the unit rod is 200–500 μm, and the porosity of the lattice interface is 70%–90%.

[0081] In one optional implementation, given that lattice units have various morphologies, one morphology is selected based on experience and the effects of each morphology. Then, according to the implantation requirements of the implantation site, the size, lattice morphology, and porosity of the lattice units at the lattice interface are selected sequentially.

[0082] Step 2.2: Determine the ring structure of the porous structure based on the geometric shape of the ring structure, the porosity of the lattice interface, the size of the lattice unit located at the lattice interface, and the lattice morphology, including: the number of ring layers and the number of lattice units in each ring layer.

[0083] In one alternative implementation, it is first necessary to determine the size and shape of the lattice unit located in the outermost ring layer. Since all lattice units have the same shape and the same radial length R, when the geometric shape and outer dimensions of the ring structure are known, several ring layers can be obtained by reverse deduction along the radial direction, thus obtaining the porous ring structure.

[0084] Step 2.3: Based on the ring structure of the porous structure, connect several lattice units together in sequence to obtain a model of the radially gradient porous structure.

[0085] Please see Figure 6 , Figure 6 This is a flowchart of step 2.3 of a method for preparing a radial gradient porous structure with a complete lattice interface provided in an embodiment of the present invention.

[0086] As shown in the figure, step 2.3 includes:

[0087] Step 2.3.1: Based on the number of lattice units in each ring layer, calculate the rotation angle θ of each lattice unit. The formula for calculating the rotation angle θ is:

[0088]

[0089] Where L is the arc length of the lattice unit cell in the ring layer along the radial direction away from the central axis; L n-1 Let θ be the arc length of the lattice unit in the (n-1)th ring layer along the radial direction away from the central axis; θ be the rotation angle of the lattice unit; and R be the radial length of the lattice unit.

[0090] In one optional implementation, based on the ring structure of the porous structure and the number of lattice units in each ring layer, the arc length L of the lattice units in the ring layer in the radial direction away from the central axis is obtained. In order to connect several ring layers and their lattice units together, due to the limitation of the aperture size, the lattice units need to be flattened step by step. The angle of this arc is the rotation angle θ of the lattice unit. Several ring layers form several arc segments. The inner arc length of the adjacent outer ring layer is equal to the outer arc length of the inner ring layer. θ can be obtained by calculating the arc length L.

[0091] Step 2.3.2: Deform the lattice unit according to the rotation angle θ to obtain the deformed lattice unit;

[0092] Step 2.3.3: Connect the deformed lattice units together in sequence to obtain a model of a porous structure with radial gradient.

[0093] In one alternative implementation, the unit rods of adjacent lattice units intersect at a common node. Different lattice unit shapes have different common nodes, but after being deformed by a rotation angle θ, the lattice units are connected together to obtain a model of a porous structure with a radial gradient.

[0094] Step 3: Based on the actual geometric shape of the porous structure, perform a lattice array on the model of the radial gradient porous structure to obtain a preliminary model of the radial gradient porous structure with a complete lattice interface.

[0095] Step 4: Verify whether the overall porosity and the porosity of the lattice interface of the preliminary model of the radial gradient porous structure with a complete lattice interface meet the implantation requirements. If the implantation requirements are met, the final model of the radial gradient porous structure with a complete lattice interface is obtained. If the implantation requirements are not met, repeat steps 2 to 3 until both the overall porosity and the porosity of the lattice interface meet the implantation requirements, and the final model of the radial gradient porous structure with a complete lattice interface is obtained.

[0096] In one optional implementation, the actual morphology of the porous structure needs to be verified, including: verifying whether the overall porosity meets the requirements of the elastic modulus; verifying whether the porosity of the outermost ring layer meets the requirements that are conducive to the growth of cancellous bone; if it does not meet the requirements, it is necessary to return to steps 2 and 3 for adjustment; if it meets the requirements, the final model of a radially gradient porous structure with a complete lattice interface is obtained.

[0097] Step 5: Based on the final model of the radial gradient porous structure with a complete lattice interface, the radial gradient porous structure with a complete lattice interface is prepared by 3D printing.

[0098] In one optional implementation, the final model of the radial gradient porous structure with a complete lattice interface is imported into model repair software for repair, and supports are added to the porous structure. Then, it is imported into slicing software for slicing to obtain the slicing strategy required for 3D printing. Finally, the slicing strategy is imported into the 3D printing equipment to complete the preparation of the porous structure.

[0099] Furthermore, the porous structure is combined with the solid part of the implant to obtain the implant.

[0100] This invention provides a method for fabricating a radially gradient porous structure with a complete lattice interface. The porous structure is prepared according to the implantation requirements of the implantation site. A ring layer and its constituent lattice units are designed inwards from the lattice units at the lattice interface. The pore size of the lattice units in the ring layer increases radially outwards to form a radial gradient. The overall porosity of the porous structure and the porosity of the lattice interface are used as verification criteria to ensure that the porous structure possesses both a complete lattice surface and good structural strength. Finally, the porous structure is fabricated using 3D printing additive manufacturing. This method is convenient, reliable, and adaptable to the fabrication requirements of different porous structures.

[0101] Example 3

[0102] Please see Figure 7 , Figure 7 This is a schematic diagram of a porous cylindrical implant provided in an embodiment of the present invention.

[0103] As shown in the figure, the present invention has a porous implant with a radial gradient cylindrical structure having a complete lattice interface. The porous structure is coaxially fixedly connected with the solid part to form the implant. The porous implant can be placed in orthopedic implants such as implants or femoral head support rods. The porous structure is used to provide ingrowth space for bone cells.

[0104] In one optional embodiment, the porous structure is disposed in the middle section of the implant. The porous structure is cylindrical in shape, and the lattice units inside the porous structure are arranged in a radial gradient periodic pattern. The porous structure is coaxially connected to the solid part of the implant.

[0105] In one optional embodiment, a porous structure is disposed on the femoral head support rod body, and the porous structure is arranged in a radial gradient along the central axis of the femoral head support rod.

[0106] In one alternative embodiment, the lattice unit of the porous structure of the femoral head support rod is a diamond structure.

[0107] Please refer to the above. Figure 8 and Figure 9 , Figure 8 It is a finite element analysis diagram of a porous structure of a cylinder using a common rectangular array Boolean operation; Figure 9This is a finite element analysis diagram of a radial gradient porous structure of a cylinder with a complete lattice interface provided in an embodiment of the present invention.

[0108] As shown in the figure, finite element simulations were performed on the porous structure of ordinary rectangular array Boolean operation and the porous structure of complete lattice unit, respectively. By applying a fixed constraint to one end of the porous structure and a load of 200N to the other end, the tensile test of the porous structure was simulated, and the maximum tensile stress and stress distribution were observed. The results are shown in the table below.

[0109] Table 1 Maximum tensile stress and stress distribution of porous structures

[0110]

[0111] It can be seen that the stress distribution in the radially gradient porous structure decreases outward along the axis at the diameter nodes of the unit rods. The maximum tensile stress on the porous structure is 658.9 MPa, which does not exceed the yield strength of the material (the yield strength of common TC4 titanium alloy is 880 MPa). In contrast, the stress distribution in the ordinary rectangular array porous structure is uniformly distributed at the diameter nodes of the unit rods, and the maximum tensile stress on the porous structure is 3222 MPa, which is much greater than its yield strength. That is, at the maximum tensile stress, yield failure or even fracture occurs at the location of the ordinary rectangular array porous structure. Therefore, porous implants using a radially gradient porous structure arrangement have a significant structural strength advantage.

[0112] Example 4

[0113] Please see Figure 10 , Figure 10 This is a schematic diagram of the porous structure of the double cylinder provided in an embodiment of the present invention.

[0114] As shown in the figure, the porous structure is set in the petal-shaped or double-cylindrical implant, such as intramedullary nails and other bone implants. The model itself has good anti-rotation properties, which provides stability for the implant in the early implantation stage. The radially arranged porous structure reduces the elastic modulus of the implant, enhances the mechanical strength of the bone implant, and provides space for bone cell growth.

[0115] In one alternative implementation, the lattice unit of the porous structure of bone implants such as intramedullary nails is a body-centered cubic lattice unit.

[0116] It is worth noting that after forming a model of a porous structure with a radial gradient, the petal-shaped or double-cylindrical shape still needs to select lattice units to meet the requirements of its external dimensions. Through the lattice array, some lattice units will be screened out as a whole, but the porous structure can still retain a complete lattice interface.

[0117] Please see Figure 11 , Figure 11 This is a schematic diagram of a porous implant with a double cylinder structure provided in an embodiment of the present invention.

[0118] As shown in the figure, the porous structure of the present invention is used for distal radius prostheses. Intramedullary nails need to be inserted into the medullary cavity of the distal radius prosthesis to fix the distal radius prosthesis to the bone. Therefore, the intramedullary nail needs to have anti-rotation function to prevent the distal radius prosthesis from rotating and shifting after installation. The porous structure design reduces the elastic modulus of the intramedullary nail, and the porous structure arranged along the diameter of the central axis unit rod enhances the mechanical strength of the intramedullary nail.

[0119] In one alternative implementation, the distal radius prosthesis is connected to the intramedullary nail along the same central axis; the connection portion is a solid structure, and the portion of the intramedullary nail inserted into the medullary cavity is configured as a radially gradient porous structure.

[0120] Example 5

[0121] Please refer to the above. Figure 12 and Figure 13 , Figure 12 This is a front view of the porous structure of the spherical shell provided in an embodiment of the present invention; Figure 13 This is a top view of the porous structure of the spherical shell provided in an embodiment of the present invention.

[0122] As shown in the figure, the porous structure is used in the acetabular cup. The porous structure is arranged in a periodic spherical shell shape and is set on the surface of the acetabular cup and coaxially connected with the acetabular cup; the lattice unit is a diamond structure.

[0123] In one optional embodiment, the diameter of the unit rod of the porous structure is 200-500 μm, and the porosity of the porous structure is 80%.

[0124] It is worth noting that the acetabular cup is a hip joint prosthesis used to connect the trunk and lower limbs, serving as a load-bearing bone implant. The porous structure on the surface of the acetabular cup has uniformly distributed lattice units to promote bone ingrowth and increase friction between the prosthesis and bone interface, preventing prosthesis loosening. The porous structure on the surface of the acetabular cup is relatively thin. In daily life, it is in a dynamic mechanical environment. Ordinary rectangular array porous structures will cut off some of the unit rods of the complete lattice units, resulting in sharp edges at the lattice interface, affecting the stress transmission on the porous structure surface, and thus affecting the load-bearing capacity of the porous structure of the acetabular cup. The smaller pore size in the central region of the acetabular cup's spherical shell can better improve the strength of the porous structure, thereby improving the fixation stability of the acetabular cup and enhancing its load-bearing capacity.

[0125] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device comprising said element. Terms such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. The orientations or positional relationships indicated by terms such as "upper," "lower," "left," and "right" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0126] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a radially gradient porous structure with a complete lattice interface, characterized in that, This is used to prepare a radial gradient porous structure with a complete lattice interface, wherein the radial gradient porous structure with a complete lattice interface comprises several ring layers. The plurality of ring layers are arranged radially along the central axis, and are connected sequentially from the innermost ring layer closest to the central axis to the outermost ring layer farthest from the central axis. Each ring layer includes a plurality of lattice units, which are arranged in a ring array and connected sequentially. The lattice units in the same ring layer are all of equal size and have the same lattice morphology. The size of the lattice units in the plurality of ring layers increases radially outward from the central axis, forming a radial gradient. The lattice units in adjacent ring layers are connected one-to-one, and the adjacent arc lengths of two correspondingly connected lattice units are equal. The radial lengths of the lattice units in the plurality of ring layers are all equal. The diameters of the unit rods of the lattice units in the plurality of ring layers are all equal. The outermost ring layer of the porous structure is a lattice interface, and the lattice units in the lattice interface are all complete lattice units. The method includes: Step 1: Based on the implantation requirements of the porous structure at the implantation site, obtain the actual geometric shape of the porous structure and the geometric shape of the annular layer structure of the porous structure. Step 2: Based on the geometric shape of the ring-layer structure of the porous structure, determine the ring-layer structure of the porous structure to obtain a model of the radially gradient porous structure; Step 3: Based on the actual geometric shape of the porous structure, perform a lattice array on the model of the radial gradient porous structure to obtain a preliminary model of the radial gradient porous structure with a complete lattice interface. Step 4: Verify whether the overall porosity and lattice interface porosity of the preliminary model of the radial gradient porous structure with complete lattice interface meet the implantation requirements. If the implantation requirements are met, the final model of the radial gradient porous structure with complete lattice interface is obtained. If the implantation requirements are not met, repeat steps 2 to 3 until both the overall porosity and lattice interface porosity meet the implantation requirements, and the final model of the radial gradient porous structure with complete lattice interface is obtained. Step 5: Based on the final model of the radial gradient porous structure with complete lattice interface, the radial gradient porous structure with complete lattice interface is prepared by 3D printing. Step 2 includes: Step 2.1: Determine the size, lattice morphology, and porosity of the lattice units located at the lattice interface according to the implantation requirements; Step 2.2: Determine the ring structure of the porous structure based on the geometric shape of the ring structure, the porosity of the lattice interface, the size and lattice morphology of the lattice units located at the lattice interface, including: the number of ring layers and the number of lattice units in each ring layer. Step 2.3: Based on the ring-layer structure of the porous structure, connect several lattice units together in sequence to obtain a model of the radially gradient porous structure; Step 2.3 includes: Step 2.3.1: Calculate the rotation angle of each lattice unit based on the number of lattice units located in each ring layer. The rotation angle The calculation formula is: ； in, It is the arc length of the lattice unit in the ring layer along the radial direction away from the central axis; The first direction along the radial direction away from the central axis The arc length of the lattice unit in each ring layer; The rotation angle of the lattice unit; denoted as the radial length of a lattice unit; Step 2.3.2: Based on the rotation angle The lattice unit is deformed to obtain the deformed lattice unit; Step 2.3.3: Connect the deformed lattice units together in sequence to obtain a model of a porous structure with radial gradient.

2. The method for preparing a radially gradient porous structure with a complete lattice interface according to claim 1, characterized in that, The porous structure is a geometric body with a symmetrical central axis, including: a cylinder, a sphere, a cylindrical shell, or a spherical shell.

3. The method for preparing a radially gradient porous structure with a complete lattice interface according to claim 1, characterized in that, The lattice morphology of the lattice unit includes: diamond unit, face-centered cubic unit, body-centered cubic unit, or honeycomb unit.

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