Porous structure bone implant material based on double positive right angle triangular pyramid spiral structure cell elements

Abstract

The invention relates to a porous structure bone implant material based on double positive right-angle triangular pyramid helical structure cell elements, which is characterized in that a bottom surface is rotated by 60 degrees by taking the center of the bottom surface of a positive triangular prism as an axis to drive the side surface to twist and deform to construct a helical structure, and positive right-angle triangular pyramids are connected to the bottom surface of the helical structure to construct the double positive right-angle triangular pyramid helical structure cell elements. Eight identical double-positive-right-angle triangular pyramid helical structure cell elements are in pairwise contact through positive-right-angle triangular pyramid side faces to construct unit bodies with cube outer contours, and the porous structure bone implant material rich in pore structures is constructed through unit body array copying. The porous bone implant constructed by adopting the bone implant material disclosed by the invention solves the problem that the service life of the bone implant cannot be met due to serious stress concentration of a unit body.

Description

Technical Field

[0001] The invention belongs to the technical field of medical materials and relates to the construction of a bone implant, in particular to a bone implant with a porous structure. Background Art

[0002] Human bone defects are a common clinical disease, often caused by injuries, osteoporosis, tumor resection, etc. Clinically, there is a mature technology for implanting metal bone implants into the human body to replace defective bones.

[0003] Porous materials have the advantages of low relative density, high specific strength, high specific surface area, light weight, sound insulation, heat insulation, good permeability, etc., and are widely used in medical, aerospace and other fields. In the medical field, porous structures as bone implants have an elastic modulus similar to that of human bones, thus avoiding the occurrence of "stress shielding". At the same time, the holes in the porous structure are interconnected, which is conducive to the growth of bone tissue. The large specific surface area also provides space for the attachment and proliferation of bone tissue, further improving the bonding strength between the metal bone implant and the host bone.

[0004] Zhang Kaiwen et al. (Numerical simulation of the effect of porous structure of 3D printed knee prosthesis on stress shielding of bone tissue [D]. Jilin: Jilin University, 2019) applied the finite element method to study the influence of the geometric shapes of three unit cells: cubic, cross-sectional cubic, and octahedral column on the strength and stiffness of the porous structure of titanium alloy.

[0005] Liang Tian et al. (Design and simulation analysis of porous bone tissue engineering scaffold composite structure [D]. Jilin: Jilin University, 2022) used the finite element method to perform compression and permeation simulation analysis on the composite scaffold composed of two unit structures, and explored the differences in elastic modulus and yield strength of different porous structures as well as permeability and flow velocity distribution.

[0006] Gao Ruining et al. (Research on the Design and Optimization Methods of Pore Structures of 3D Printed Orthopedic Implants [D]. Shanghai: Shanghai Jiao Tong University, 2020) studied the pore structure design method of TPMS, discussed and analyzed the design modeling and parameter control methods of homogeneous pore structures, gradient pore structures, and fusion pore structures, and proposed a radial gradient pore structure design method that simulates natural bones.

[0007] Du Yue et al. (Design and performance research of controllable irregular porous structures for orthopedics [D]. Jiangsu: Nanjing University of Aeronautics and Astronautics, 2020) proposed a design method for controllable irregular porous structures and studied related mechanical and permeability properties.

[0008] Guo Mengmeng et al. (Numerical simulation study on the influence of porous titanium alloy femoral stem on stress shielding of bone tissue [D]. Jilin: Jilin University, 2022) selected Cube-type, Gyroid-type and Diamond-type structures of three-periodic minimal surfaces, combined personalized solid femoral stem with porous structure, and established a porous femoral stem model.

[0009] However, in the above-mentioned studies, the regular porous structure has a complex porosity adjustment method, which makes it impossible to quickly and simply construct porous structures with different elastic moduli. Although the irregular porous structure is closer to human bone in morphology, the stress concentration phenomenon is more serious than that of the regular structure, and thus cannot meet the patient's requirements for the service life of bone implants.

[0010] Some scholars have applied the finite element method to study the influence of the geometric shape of the unit body on the strength and stiffness of the porous structure of titanium alloy. The results show that the influence of the unit topology on the stress distribution and concentration is mainly reflected in the supporting pillars. Compared with the vertical pillars, the inclined pillars have more uniform stress distribution and less stress concentration. Summary of the invention

[0011] The purpose of the present invention is to solve the problems of complex porosity adjustment and internal stress concentration of bone implants, and to provide a porous bone implant material based on double right-angle triangular pyramid spiral structure cells.

[0012] To achieve the above-mentioned purpose of the invention, the present invention provides a porous structure bone implant material based on a double right-angle triangular pyramid spiral structure cell, wherein the porous structure bone implant material is constructed by the structure cell in the following manner:

[0013] First, set a bottom side length of , the height is h A regular triangular prism is constructed, with the line connecting the centers of the two equilateral triangular bases of the regular triangular prism as the central axis, one base is fixed, and the other base is rotated 60° along the central axis, driving the three sides of the regular triangular prism to twist and deform, thereby constructing a height having two equilateral triangular bases and three curved sides. h The spiral structure of

[0014] Secondly, two right-angled triangular pyramids with the same right-angled triangular bases are connected to the two right-angled triangular bases of the spiral structure to construct a double right-angled triangular pyramid spiral structure cell, wherein the vertex of the right-angled triangular pyramid is located on the central axis of the right-angled prism, and the sides of the three right-angled triangular pyramids are isosceles right triangles, and the length of the right angle side of the isosceles right triangle is x ;

[0015] Next, eight identical double right-angled triangular pyramid spiral structure cells are used as the same vertex, and the right-angled triangular pyramid sides are contacted with each other to construct a unit body with a cube outer contour around the vertex;

[0016] Finally, the unit body is replicated in arrays in three directions of space to construct a porous bone implant material in which the right-angled triangular pyramid sides of any adjacent structural cells are connected and the structural cells are rich in pore structures.

[0017] In the present invention, the spiral structure is the core part of the structural cell. The spiral structure is formed by rotating the regular triangular prism along its central axis. The rotation process causes the side surfaces of the three regular triangular prisms to be twisted and deformed, so the three side surfaces of the spiral structure are curved surfaces.

[0018] More specifically, the curved surface is a curved surface formed by connecting two points whose sides on the upper and lower equilateral triangle bases of the spiral structure differ by 60 degrees.

[0019] Furthermore, the angle of 60° specifically refers to the angle formed by the line connecting the two points on the plane parallel to the base of the regular triangle of the spiral structure and the central axis.

[0020] Based on the construction method of the spiral structure, any cross section of the spiral structure that is parallel to the bases of the two equilateral triangles is also an equilateral triangle, but its area changes.

[0021] Furthermore, the side length of the regular triangle of any cross section on the spiral structure is y Satisfy the formula:

[0022]

[0023] in:

[0024] m The distance between the cross section and one of the bases of the regular triangle and the distance between the upper and lower two regular triangle bases h The ratio of 0≤ m ≤1;

[0025] x is the length of the right angle side of a right triangular pyramid.

[0026] Furthermore, if the six right-angled triangular pyramid side surfaces of the double right-angled triangular pyramid spiral structure cell are extended, the extended planes can intersect with each other in pairs to construct an outer contour of a small cube.

[0027] Obviously, the volume of the outer contour of the constructed small cube is 1 / 8 of the volume of the outer contour of the cube of the unit body.

[0028] That is to say, any double right-angled triangular pyramid spiral structure cell in the unit body described in the present invention can be obtained by rotating its adjacent structure cell 90° around the right-angled side length of the right-angled triangular pyramids that overlap with each other as the axis.

[0029] The present invention uses two identical right-angled triangular pyramids and a middle spiral structure to form a structural cell, and then uses the structural cells to splice into a unit body, and finally the unit body is x , y , z The array is replicated in three directions to construct a porous structure bone implant material with a porous structure array replication. Obviously, the porosity of the porous structure bone implant material constructed by the present invention is similar to the height of the spiral structure. h and the length of the right angle side of a right triangular pyramid x Therefore, simply by changing the height of the spiral structure h and the length of the right side of a right triangular pyramid x These two parameters can easily construct porous bone implant materials with different porosities.

[0030] Porous bone implant materials with different porosities have different densities. Therefore, conventional finite element analysis software is used to analyze a finite number of bone implants with different helical structure heights. h and the length of the right side of a right triangular pyramid x By performing compression analysis on the porous structure bone implant materials and fitting the obtained data, the relationship between the elastic modulus and the height of the spiral structure and the length of the right-angled side of the right-angled triangular pyramid can be obtained; then, according to different bone elastic modulus requirements, porous structure bone implant materials with matching mechanical properties are selected and Boolean operations are performed on the entity with the implant contour, and finally a porous bone implant that meets the mechanical requirements can be constructed by combining porous structure bone implant materials with different porosities.

[0031] The porosity adjustment method of the porous structure bone implant material of the present invention is simple and convenient, and only the height of the spiral structure needs to be changed. h and the length of the right side of a right triangular pyramid x By adjusting the size parameters, the porosity can be adjusted in real time, so that porous bone implant materials with different elastic moduli can be constructed quickly and concisely. At the same time, the present invention obtains the compression data of porous bone implant materials with different porosities through finite element analysis, and obtains the functional relationship between the height of the spiral structure and the length of the right-angled side of the right-angled triangular pyramid and the elastic modulus through fitting, which greatly simplifies the construction process of the porous bone implant.

[0032] When the porous bone implant constructed by the porous structure bone implant material of the present invention is subjected to external load, each structural cell has the same stress distribution law, and the stress range of the same unit body is reduced, which solves the problem that the existing porous bone implants have serious unit body stress concentration, resulting in brittle failure of the structure, reduced fatigue life, and cannot meet the patient's requirements for the service life of the bone implant. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic structural diagram of the porous structure bone implant material of the present invention.

[0034] Figure 2 It is a schematic diagram of the structure of a unit cell 1 in a porous structure bone implant material.

[0035] Figure 3 Is used to build Figure 2 Schematic diagram of the structure of the double right-angled triangular pyramid spiral structure cell 10 of the unit body.

[0036] Figure 4 yes Figure 3 Schematic diagram of the structure of the middle helical structure 13.

[0037] Figure 5 Is used to build Figure 4 A schematic diagram of the structure of a regular triangular pyramid of the spiral structure 13 .

[0038] Figure 6 yes Figure 4 A top view of the spiral structure 13 .

[0039] Figure 7 It is a schematic diagram of the formation of the upper curved surface 105 of the spiral structure 13.

[0040] Figure 8 It is a cross-sectional view of the double right-angle triangular pyramid spiral structure cell 10 at different positions.

[0041] Fig. 9 yes Figure 3 Schematic diagram of the structure of a right-angled triangular pyramid.

[0042] Fig.10 It is an extended outline diagram of the double right-angled triangular pyramid spiral structure cell 10.

[0043] Fig.11 The flowchart is a construction flow chart of a porous structure bone implant material based on a double right-angle triangular pyramid spiral structure cell 10.

[0044] Fig.12 It is the stress distribution cloud diagram of unit body 1 under the action of compression load.

[0045] Fig.13 is the right-angle side length of the building block in Example 1x - Elastic modulus data fitting curve graph. Implementation

[0046] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of the present invention so that those skilled in the art can well understand and utilize the present invention, rather than limiting the scope of protection of the present invention.

[0047] The following examples provide in detail a specific method for constructing a porous structure bone implant material based on a double right-angle triangular pyramid spiral structure cell of the present invention. The porous structure bone implant material constructed is as follows: Figure 1 As shown, it is Figure 2 The unit body 1 having a cubic outer contour is shown in the space x , y , z The array is replicated in three directions, and a closed space is formed at the connection between the unit bodies 1, thereby constructing a porous bone implant material with a rich pore structure.

[0048] Wherein, the unit body 1 is based on Figure 3 The double right-angle triangular pyramid spiral structure cell 10 is assembled by splicing. More specifically, the double right-angle triangular pyramid spiral structure cell 10 is further composed of two identical right-angle triangular pyramids on both sides and a spiral structure 13 in the middle.

[0049] For the convenience of description, in this embodiment, the two identical right-angled triangular pyramids located on both sides of the spiral structure 13 are named as inner right-angled triangular pyramid 11 and outer right-angled triangular pyramid 12, wherein the inner right-angled triangular pyramid 11 is a side used to be spliced ​​with each other to form a unit body 1, and the outer right-angled triangular pyramid 13 is a side located on the surface of the unit body 1 and used to connect with the right-angled triangular pyramid part of the surface of the adjacent unit body.

[0050] The specific structure of the helical structure 13 is as follows Figure 4 As shown, it is obtained by twisting a regular triangular prism at a certain angle.

[0051] Specifically, set a Figure 5 The height shown is h The upper base 104 and the lower base 106 of the regular triangular prism are the same, both are regular triangles. At the same time, for the convenience of description, the length of the base side of the regular triangular prism is defined as ,in x To constitute Figure 3 The length of the right angle side of the right angle triangular pyramid of the double right angle triangular pyramid spiral structure cell 10 is the length of the right angle edge 108 in the figure.

[0052] The center of the upper base 104 of the regular triangular prism o and the center of the lower bottom surface 106 o ' o - o ' is the central axis, the lower bottom surface 106 is fixed, and the upper bottom surface 104 is Figure 6 Shown along the central axis o - o 'Rotate 60° counterclockwise, and at the same time, the sides of the three regular triangular prisms are twisted and deformed to form a curved surface 105, and the constructed Figure 4 The spiral structure 13 shown is composed of an upper base 104 and a lower base 106 of the same equilateral triangle, and three curved surfaces 105 on the side.

[0053] The angle difference between the upper bottom surface 104 and the lower bottom surface 106 of the spiral structure 13 can be Figure 6 The top view of the spiral structure 13 further shows that the vertex angles of the two regular triangles of the upper bottom surface 104 and the lower bottom surface 106 and the central axis o - o The angle between the vertical lines of ' is 60°, that is, the line between the two vertex angles is a straight line on the curved surface 105. It is not difficult to understand that Figure 7 As shown, the curved surface 105 is a curved surface formed by connecting lines of two points on the sides of the upper bottom surface 104 and the lower bottom surface 106 whose angles differ by 60°.

[0054] Based on the above construction method, any cross section parallel to the two equilateral triangle bottom surfaces on the formed double right-angled triangular pyramid spiral structure cell 10 should also be an equilateral triangle. Figure 8 As shown, the cross-sectional views of the double right-angled triangular pyramid spiral structure cell 10 observed from bottom to top are respectively given, wherein the cross-sectional views AA and EE correspond to the upper bottom surface 104 and the lower bottom surface 106 of the spiral structure 13, respectively, and the cross-sectional view CC is the cross-sectional view at half the height of the spiral structure 13. It can be seen that the different cross-sectional views are regular triangles after being rotated at different angles, but at the same time, due to the rotational distortion, the area of ​​the regular triangle will slightly change, the regular triangle area of ​​the cross-sectional views AA and EE is the largest, and the regular triangle area of ​​the cross-sectional view CC is the smallest.

[0055] More specifically, the side length of any equilateral triangle section parallel to the bottom surface of the spiral structure 13 is y The vertical distance between the cross section and the lower bottom surface 106 and the length of the right angle side of the right triangle pyramid x The following relationship is satisfied:

[0056]

[0057] m is the distance between the cross section and the bottom surface 106 and the height of the spiral structure h The ratio of 0≤ m ≤1.

[0058] For example, for section AA, m = h / h =1, y = , is the length of the bottom surface of the spiral structure. This section is equivalent to the upper bottom surface 104 and has the largest cross-sectional area. For section CC, m =0.5 h / h =0.5, y = , the cross-sectional area is the smallest. For section EE, m =0 / h =0, y = , is the side length of the bottom surface of the spiral structure, and this section is equivalent to the lower bottom surface 106, and the cross-sectional area is also the largest.

[0059] On the basis of the spiral structure 13, the following is constructed: Fig. 9 The two identical right-angled triangular pyramids shown include an inner right-angled triangular pyramid 11 and an outer right-angled triangular pyramid 12. The inner right-angled triangular pyramid bottom surface 103 and the outer right-angled triangular pyramid bottom surface 107 are both regular triangles, which are exactly the same as the upper bottom surface 104 (lower bottom surface 106) of the spiral structure 13, and the bottom side length is The three sides of the inner right-angled triangular pyramid 11 and the outer right-angled triangular pyramid 12 are all isosceles right triangles, and the length of the right angle side of the right angle edge 108 is x , the right-angle vertex is located on the central axis of the base.

[0060] The inner right-angled triangular pyramid 11 and the outer right-angled triangular pyramid 12 are connected to the two ends of the spiral structure 13 respectively, the bottom surface 103 of the inner right-angled triangular pyramid 11 overlaps with the upper bottom surface 104 of the spiral structure 13, and the bottom surface 107 of the outer right-angled triangular pyramid 12 overlaps with the lower bottom surface 106 of the spiral structure 13, so as to construct Figure 3 The double right-angled triangular pyramid spiral structure cell 10 is shown, and the right-angled vertex 101 of the inner right-angled triangular pyramid 11 and the right-angled vertex 102 of the outer right-angled triangular pyramid 12 are located at the central axis of the spiral structure 13. o - o 'superior.

[0061] If Figure 3 The six right-angled triangular pyramid isosceles right triangle sides of the constructed double right-angled triangular pyramid spiral structure cell 10 are extended, as shown in Fig.10As shown, the extended planes can intersect with each other to form a small cube outer contour. Fig.10 The volume of the outer contour of the small cube is Figure 2 Unit 1 is 1 / 8 of the volume of the outer contour of the cube.

[0062] like Fig.11 As shown in (a), for the above-constructed double right-angled triangular pyramid spiral structure cell 10, a right-angled edge 108 of the right-angled triangular pyramid 11 is used as the axis, and it is rotated 90° in the direction shown in the figure for replication, so as to obtain Fig.11 (b) shows a transition cell 20 obtained by combining two double right-angled triangular pyramid spiral structure cells 10.

[0063] That is to say, any double right-angled triangular pyramid spiral structure cell 10 can be obtained by rotating its adjacent structure cell 90° with the right-angled side length of the right-angled triangular pyramids that overlap as the axis.

[0064] Then, the transition cell 20 is rotated 90°, 180° and 270° respectively with the right angle edge 108 which is perpendicular to the joint surface of the inner right angle triangular pyramid 11 of the two double right angle triangular pyramid spiral structure cells 10 as the axis, and the transition cell 20 can be obtained. Fig.11 In (c), the unit cell 1 is obtained by combining eight identical double right-angled triangular pyramid spiral structure cells 10, whose inner right-angled triangular pyramids 11 are in contact with each other on their side surfaces.

[0065] Finally, the unit body 1 is array-copied in three directions of space, so that the sides of the outer right-angled triangular pyramids 12 on adjacent unit bodies 1 are connected to each other, and the combination is obtained. Fig.11 (d) Porous bone implant material with rich pore structures between structural cells.

[0066] Example 1

[0067] according to Figure 1 It can be seen that the porosity of the porous bone implant material constructed, that is, the material density, is proportional to the height of the spiral structure. h and the length of the right angle side of a right triangular pyramid x Related.

[0068] Fixed helical height h , reduce the length of the right angle side of the right triangular pyramid x , the outer contour volume of the cube of the constructed unit body is slightly reduced due to the reduction of the right-angled side length of the right-angled triangular pyramid, but the pore volume between the structural cells will increase, resulting in an increase in porosity and a decrease in material density.

[0069] Fixed right angle side length of right triangle pyramid x , increasing the height of the spiral structure h, the outer contour volume of the cube of the constructed unit body increases significantly due to the increase in the height of the spiral structure. At the same time, since the right-angled side length of the right-angled triangular pyramid is fixed, the structural cell becomes more slender, and the pore volume between the structural cells will also increase, which also leads to an increase in porosity and a decrease in material density.

[0070] Therefore, simply changing the height of the spiral structure h and the length of the right side of a right triangular pyramid x These two parameters can be used to construct porous bone implant materials with different densities.

[0071] In order to understand the stress distribution of porous bone implant materials under load, this embodiment constructs a standard unit body, which uses titanium alloy Ti6Al4V as the base material. The outer cube outline of the unit body has a side length of 2 mm, and the right angle side length of the right triangle pyramid is x It is 0.383mm.

[0072] Import the above standard unit body into ABAQUS software, set the upper and lower rigid plates to contact the upper and lower bottom surfaces of the unit body, constrain all degrees of freedom of the lower rigid plate, set the upper rigid plate to move along the negative direction of the Z axis, and make the strain of the unit body 0.01. In order to avoid mutual penetration, the contact between the unit body and the rigid plate is set to frictionless general contact. The unit body material properties are set as Ti6Al4V, the elastic modulus is 110Gpa, and the Poisson's ratio is 0.3.

[0073] Finally got Fig.12 The stress distribution of the unit cell is shown.

[0074] It can be seen from the above test results that when the porous bone implant constructed with the porous structure bone implant material of the present invention is subjected to external loads, each structural cell has the same stress distribution law, and compared with the existing bone implant unit body combined with a vertical rod and a horizontal rod, the stress variation range of the same unit body is reduced, which solves the problem that the existing porous bone implant has serious stress concentration in the unit body, resulting in brittle failure of the structure, reduced fatigue life, and cannot meet the patient's requirements for the service life of the bone implant.

[0075] Example 2

[0076] In this embodiment, titanium alloy Ti6Al4V is used as a matrix material to prepare a porous structure bone implant material, and then a porous bone implant is prepared.

[0077] Set the height of the helix h The value is fixed at 1 mm, and the length of the right angle side of the right triangle pyramid is changed. xAdjust the porosity of the unit body. That is, keep the size of the inner and outer right-angled triangular pyramids the same, and change the length of the right-angled side of the right-angled triangular pyramid. x The diameters of the porous structures were 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm and 0.8 mm respectively. Seven groups of porous bone implant materials were constructed in the 3D modeling software SolidWorks. The difference between the porous bone implant materials in different groups was only the length of the right angle side of the right triangle pyramid. x This parameter is different and is exported in step file format to achieve porosity adjustment.

[0078] Import one set of step file formats of porous bone implant material 3D model into ABAQUS software, define material properties as Ti6AI4V, elastic modulus as 110Gpa, Poisson's ratio as 0.3. Fix the degree of freedom of the bottom surface of the porous bone implant material in any direction, apply a vertical downward displacement load on the top, derive the stress-strain curve during compression, and obtain the elastic modulus of the porous bone implant material through the stress-strain curve.

[0079] The above operation was repeated, and 7 groups of porous structure bone implant materials were successively imported into ABAQUS for compression simulation to obtain the elastic modulus data corresponding to the 7 groups of porous structure bone implant materials.

[0080] The right-angled side lengths of the right-angled triangular pyramids of the above 7 groups of porous structure bone implant materials are x The corresponding elastic modulus E Import into origin software, with the length of the right angle side of the right triangle pyramid x is the independent variable, elastic modulus E As the dependent variable, the corresponding function formula of the two is obtained by fitting:

[0081] E =48.12973 x 3.844 .

[0082] Through CT scanning, reverse modeling is used to obtain the personalized structure of the human vertebrae, and a solid model of the intervertebral fusion device that completely matches the external contour of the vertebrae is constructed according to the specific shape of the vertebrae.

[0083] The elastic modulus of human vertebral cortical bone is 1200Mpa, so the intervertebral fusion device in contact with it should also have the same elastic modulus to avoid the occurrence of stress shielding. Substituting the elastic modulus of vertebral cortical bone into the above formula, the corresponding right angle side length of the right-angled triangular pyramid is obtained. x The size is 0.383mm.

[0084] A porous structure bone implant material with a right-angled triangular pyramid having a right-angled side length of 0.383 mm is constructed in three-dimensional space so that its outer contour size is larger than the constructed intervertebral fusion device entity model.

[0085] The intervertebral fusion device entity model is completely placed inside the porous structure bone implant material, and a Boolean intersection operation is performed on the two, so as to construct an intervertebral fusion device porous bone implant with the characteristics of the porous structure bone implant material.

[0086] The above embodiments of the present invention do not describe all the details in detail, nor limit the present invention to the above embodiments. Various changes, modifications, substitutions and variations made by ordinary technicians in this field without departing from the principles and purpose of the present invention should be included in the protection scope of the present invention.

Claims

1. A porous structure bone implant material based on a double right-angle triangular pyramid spiral structure cell, wherein the porous structure bone implant material is obtained by constructing the structure cell in the following manner: S1: Set a bottom side length of , the height is h A regular triangular prism is constructed, with the line connecting the centers of the two equilateral triangular bases of the regular triangular prism as the central axis, one base is fixed, and the other base is rotated 60° along the central axis, driving the three sides of the regular triangular prism to twist and deform, thereby constructing a height having two equilateral triangular bases and three curved sides. h The spiral structure of S2: Connect two right-angled triangular pyramids with the same right-angled triangular bases on the two right-angled triangular bases of the spiral structure to construct a double right-angled triangular pyramid spiral structure cell, wherein the apex of the right-angled triangular pyramid is located on the central axis of the right-angled prism, and the sides of the three right-angled triangular pyramids are isosceles right triangles, and the length of the right angle side of the isosceles right triangle is x ; S3: 8 identical double right-angled triangular pyramid spiral structure cells are formed with the vertex of the right-angled triangular pyramid on one side of the structure cell as the same vertex, and the right-angled triangular pyramid sides are contacted with each other to construct a unit body with a cube outer contour around the vertex; S4: The unit cell is replicated in arrays in three directions of space to construct a porous bone implant material in which the right-angled triangular pyramid sides of any adjacent structural cells are connected and the structural cells have a pore-rich structure.

2. The porous structure bone implant material according to claim 1, characterized in that The curved surfaces of the three sides of the spiral structure are formed by the lines connecting two points on the sides of the upper and lower equilateral triangle bases with an angle difference of 60°, and the angle is the angle formed by the line connecting the two points on the plane parallel to the equilateral triangle base and the central axis.

3. The porous bone implant material according to claim 1, characterized in that The planes extending from the side surfaces of the six right-angled triangular pyramids of the double right-angled triangular pyramid spiral structure cell intersect to construct an external contour of a small cube.

4. The porous structure bone implant material according to claim 3, characterized in that The volume of the outer contour of the small cube is 1 / 8 of the outer contour of the cube of the unit body.

5. The porous structure bone implant material according to claim 1, characterized in that Any cross section of the spiral structure parallel to the bases of the two equilateral triangles is also an equilateral triangle, and the length of the side of any cross section is y Satisfy the formula: ， in: m The distance between the cross section and one of the bases of the regular triangle and the distance between the upper and lower two regular triangle bases h The ratio of 0≤ m ≤1; x is the length of the right angle side of a right triangular pyramid.

6. The porous bone implant constructed by using the porous structure bone implant material based on the double right-angle triangular pyramid spiral structure cell of claim 1 is to construct a porous bone implant with different spiral structure heights. h and the length of the right side of a right triangular pyramid x The porous bone implant materials with different porosities were analyzed by finite element analysis software. h and the length of the right side of a right triangular pyramid x Compression analysis was performed on porous structure bone implant materials, and the obtained data were fitted to obtain the relationship between the elastic modulus and the height of the spiral structure and the length of the right-angled side of the right-angled triangular pyramid. According to the requirements of different bone elastic moduli, porous structure bone implant materials with matching mechanical properties were selected for Boolean operation with entities with bone implant contours to construct a porous bone implant that meets the mechanical requirements and is composed of porous structure bone implant materials with different porosities.

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