Medical Implant Porous Scaffold Structure Having Low Modulus

Abstract

A medical implant porous scaffold structure having low modulus, wherein said structure is formed by multiple basic units superposed sequentially along the three-dimensional directions in three-dimensional space, each of the basic units is composed of a quadrangular prism or hexagonal prism having central interconnected pores encircled by four or six side walls, each of the side walls is composed by a “X-type” frame structure formed by two crossed ribs, and the central interconnected pores of the adjacent basic units arranged along the axis direction of the quadrangular prism or the hexagonal prism are interconnected to each other. The structure could not only reduce the modulus of the implant, make the modulus of the implant and strength achieve an ideal match, improve the configuration of traditional metal implants to optimize the distribution of mechanical and weaken the stress shielding effect; but also has a regular interconnected pores structure which is conducive to bone tissue in-growth, and can increase mutual locking of bone tissue and implant and shorten the recovery time of patients.

Claims

1. A medical implant porous scaffold structure having low modulus, wherein said structure is formed by multiple basic units superposed sequentially along the three-dimensional directions in three-dimensional space, each of the basic units is composed of a quadrangular prism or hexagonal prism having central interconnected pores encircled by four or six side walls, each of the side walls is composed by a “X-type” frame structure formed by two crossed ribs, and the central interconnected pores of the adjacent basic units arranged along the axis direction of the quadrangular prism or the hexagonal prism are interconnected to each other.

2. The medical implant porous scaffold structure having low modulus of claim 1, wherein the inscribed circle radius of the cross section of the central interconnected pore is 150 μm to 750 μm.

3. The medical implant porous scaffold structure having low modulus of claim 2, wherein the ratio of the equivalent circle diameter of the cross section of the rib to the length of the rib is 0.1 to 0.5; the ratio of the height of the quadrangular prism or the hexagonal prism to the base length of the side wall of the quadrangular prism or the hexagonal prism is 1.0 to 2.5.

4. The medical implant porous scaffold structure having low modulus of claim 3, wherein the cross section area of the central interconnected pore is greater than the cross section area of the pore of the “X-type” framework structure in the sidewall.

Description

DESCRIPTION OF THE DRAWING

[0035] FIG. 1 is the top view of the basic unit of the hexagonal prism according to the present disclosure.

[0036] FIG. 2 is the side view of the basic unit of the hexagonal prism according to the present disclosure.

[0037] FIG. 3 is the top view of the basic unit of the quadrangular prism according to the present disclosure.

[0038] FIG. 4 is the side view of the basic unit of the quadrangular prism according to the present disclosure.

[0039] FIG. 5 is the finite element analysis flow chart according to the present disclosure.

[0040] FIG. 6 is a bar graph of the relative modulus and yield strength of the cylindrical vertical and straight rod structure, “X type” hexagonal prism, granatohedron structure according to the present disclosure.

[0041] FIG. 7 is the finite element mesh division of the basic unit of the hexagonal prism according to the present disclosure.

[0042] FIG. 8 is the finite element mesh division of the basic unit of the quadrangular prism according to the present disclosure.

[0043] FIG. 9 is the finite element simulation analysis process chart of the basic unit of the hexagonal prism according to the present disclosure;

[0044] FIG. 10 is the finite element simulation analysis process chart of the basic unit of the quadrangular prism according to the present disclosure;

[0045] FIG. 11 is the state diagram of the change of the modulus of the hexagonal prism with the structural parameters.

[0046] FIG. 12 is the state diagram of the change of the modulus of the quadrangular prism with the structural parameters.

[0047] Meaning of the reference indicia of the accompanying drawings:

[0048] r is the inscribed circle radius of the cross section of the central interconnected pore;

[0049] t is the thickness or the equivalent circle diameter of the cross section of the rib of the “X-type” framework;

[0050] l is the length of the rib of the “X-type” framework;

[0051] c is the height of the quadrangular prism or the hexagonal prism;

[0052] a is the base length of the quadrangular prism or the hexagonal prism;

[0053] η.sub.1 is the ratio of the height c to the base length a of the quadrangular prism or the hexagonal prism.

Specific Mode for Carrying Out the Invention

[0054] The present disclosure will be illustrated hereinafter detailedly with reference to the following embodiments and examples.

[0055] The specific embodiments for carrying out the invention are described as follows.

[0056] A medical implant porous scaffold structure having low modulus, wherein said structure is formed by multiple basic units superposed sequentially along the three-dimensional directions in three-dimensional space, each of the basic units is composed of a quadrangular prism or hexagonal prism having central interconnected pores encircled by four or six side walls, each of the side walls is composed by a “X-type” frame structure formed by two crossed ribs, and the central interconnected pores of the adjacent basic units arranged along the axis direction of the quadrangular prism or the hexagonal prism are interconnected to each other.

[0057] The rib of the prism may have a cross section in the shape of solid circle, solid oval, solid polygon, hollow circular ring, hollow oval ring or hollow polygonal ring.

[0058] In order to meet the bio-functional requirements of the support materials, the inscribed circle radius r of the cross section of the central interconnected pore is 150 μm to 750 μm.

[0059] The ratio of the equivalent circle diameter of the cross section of the ribs to the length of the rib is 0.1 to 0.5; the ratio of the height of the quadrangular prism or the hexagonal prism to the base length of the side wall of the quadrangular prism or the hexagonal prism is 1.0 to 2.5.

[0060] For the basic unit of the hexagonal prism, its structural feature of the overall shape can be determined by the ratio of η.sub.1 of the height c to the base length a of the hexagonal prism (η.sub.1c/a); the relative density of the basic unit of the hexagonal prism can be determined by the ratio of η.sub.2 of the thickness t of the rib of the “X-type” framework (or the equivalent circle diameter of the cross section) to the length l of the rib of the “X-type” framework (η.sub.2=t/l).

[0061] For the basic unit of the quadrangular prism, its structural feature of the overall shape can be determined by the ratio of η.sub.1 of the height c to the base length a of the quadrangular prism (η.sub.1=c/a); the relative density of the basic unit of the quadrangular prism can be determined by the ratio of η.sub.2 of the thickness t of the rib of the “X-type” framework (or the equivalent circle diameter of the cross section) to the length l of the rib of the “X-type” framework (η.sub.2=t/l).

[0062] The cross-sectional area of the central interconnected pore is larger than the cross-sectional area of the pores of the “X-type” framework structure in the side wall.

[0063] The whole structure of the scaffold structure can be calculated by finite element method. Firstly, establishing the geometric model of the scaffold (such as the “X-type” quadrangular prism or the “X-type” hexagonal prism, etc.) by a drawing software, and at the same time, setting the structure parameters (r, η.sub.1 and η.sub.2) of the scaffold structure; and then introducing a finite element analysis software (such as Ansys, Comsol or Abaqus, etc.), defining the parameters (E and v, etc.) of the materials; setting the boundary conditions, loading conditions and dividing mesh; then carrying on the finite element calculation and analysis. According to the requirement of modulus lower than 30 GPa, if the whole modulus of the selected scaffold structure can meet the requirements, the selected scaffold structure solution would be established. Otherwise, the parameters (r, η.sub.1 and η.sub.2) of the scaffold structure should be reset, and calculated and judged in accordance with the above procedure, so as to obtain the materials of the scaffold structure and the parameters ranges meeting the conditions of low modulus.

[0064] α-Ti Example Group

EXAMPLE 1

[0065] For the basic unit of the hexagonal prism, when α-Ti (E=110 GPa, v=0.33) was selected as the implant materials, as shown in FIG. 3, the finite element method can be used to calculate the relationship between the relative modulus of the scaffold materials and the relative density of the scaffold. The result showed that when η.sub.1 was selected to range from 1.0 to 2.5, η.sub.2 was selected to range from 0.10 to 0.50, and the inscribed circle radius r of the interconnected pore was selected to range from 150 μm to 750 μm, the relative modulus of the scaffold materials could be less than 30 GPa, meeting the modulus range of human cortical bone.

EXAMPLE 2

[0066] For the basic unit of the quadrangular prism, when α-Ti (E=110 GPa, v=0.33) was selected as the implant materials, as shown in FIG. 4, the finite element method can be used to calculate the relationship between the relative modulus of the scaffold materials and the relative density of the scaffold. The result showed that when η.sub.1 was selected to range from 1.0 to 2.5, η.sub.2 was selected to range from 0.1 to 0.35, and the inscribed circle radius r of the interconnected pore was selected to range from 150 μm to 750 μm, the relative modulus of the scaffold materials could be less than 30 GPa, meeting the modulus range of human cortical bone.

[0067] Mg Example Group

EXAMPLE 3

[0068] For the basic unit of the hexagonal prism, when Mg (E=44 GPa, v=0.26) was selected as the implant materials, as shown in FIG. 3, the finite element method can be used to calculate the relationship between the relative modulus of the scaffold materials and the relative density of the scaffold. The result showed that when η.sub.1 was selected to range from 1 to 2.5, η.sub.2 was selected to range from 0.1 to 0.5, and the inscribed circle radius r of the interconnected pore was selected to range from 150 μm to 750 μm, the relative modulus of the scaffold materials could be less than 30 GPa, meeting the modulus range of human cortical bone.

EXAMPLE 4

[0069] For the basic unit of the quadrangular prism, when Mg (E=44 GPa, v=0.26) was selected as the implant materials, as shown in FIG. 4, the finite element method can be used to calculate the relationship between the relative modulus of the scaffold materials and the relative density of the scaffold. The result showed that when η.sub.1 was selected to range from 1.2 to 2.5, η.sub.2 was selected to range from 0.15 to 0.50, and the inscribed circle radius r of the interconnected pore was selected to range from 150 μm to 750 μm, the relative modulus of the scaffold materials could be less than 30 GPa, meeting the modulus range of human cortical bone.

[0070] Co—Cr—Mo Example Group

EXAMPLE 5

[0071] For the basic unit of the hexagonal prism, when Co—Cr—Mo (E=248 GPa, v=0.30) was selected as the implant materials, as shown in FIG. 3, the finite element method can be used to calculate the relationship between the relative modulus of the scaffold materials and the relative density of the scaffold. The result showed that when η.sub.1 was selected to range from 1.0 to 1.5, η.sub.2 was selected to range from 0.10 to 0.25, and the inscribed circle radius r of the interconnected pore was selected to range from 150 μm to 750 μm, the relative modulus of the scaffold materials could be less than 30 GPa, meeting the modulus range of human cortical bone.

EXAMPLE 6

[0072] For the basic unit of the quadrangular prism, when Co—Cr—Mo (E=248 GPa, v=0.30) was selected as the implant materials, as shown in FIG. 4, the finite element method can be used to calculate the relationship between the relative modulus of the scaffold materials and the relative density of the scaffold. The result showed that when η.sub.1 was selected to range from 1.0 to 2.3, η.sub.2 was selected to range from 0.10 to 0.45, and the inscribed circle radius r of the interconnected pore was selected to range from 150 μm to 750 μm, the relative modulus of the scaffold materials could be less than 30 GPa, meeting the modulus range of human cortical bone.

[0073] The above specific embodiments were intended to detailedly explain the technical solution according to the disclosure. The present disclosure should not be limited to just the above embodiments. Any improvement or replacement according to the principles according to the disclosure should be included within the protection scope of the invention.