CN107198596B

CN107198596B - Acetabular cup

Info

Publication number: CN107198596B
Application number: CN201610158355.2A
Authority: CN
Inventors: 叶雷
Original assignee: Chongqing Runze Pharmaceutical Co Ltd
Current assignee: Chongqing Runze Pharmaceutical Co Ltd
Priority date: 2016-03-18
Filing date: 2016-03-18
Publication date: 2020-05-26
Anticipated expiration: 2036-03-18
Also published as: CN107198596A

Abstract

An acetabulum cup comprises a hemispherical lining, a backing and a porous material, wherein the porous material is arranged on the outer surface of the backing and is a multi-level porous metal material, the multi-level porous metal material has at least more than two levels of grading grade, the multi-level porous metal material is composed of various levels of pore cavities graded according to the pore diameters of the material and various levels of cavity walls surrounding the formed pore cavities, a three-dimensional space surrounds the cavity walls forming the upper-level large pore cavities and is composed of lower-level porous metal materials, each level of pore cavities are communicated with each other, and the various levels of pore cavities are also communicated with each other; the acetabular cup is beneficial to tissue growing inside the acetabular cup, the acetabular cup is tightly fused with surrounding bone tissues, the interface is stable, and the loosening phenomenon is avoided.

Description

Acetabular cup

Technical Field

The invention relates to the field of medical instruments, in particular to an artificial acetabular cup.

Background

The hip joint is one of the largest, most important joints of the human body, which bears a large portion of the body weight of the human body. However, diseases such as osteoarthritis, rheumatoid arthritis, aseptic necrosis of femoral head, traumatic arthritis, congenital acetabular dysplasia and the like can cause hip joint pain and loss of functions thereof, thereby seriously affecting the life of patients. Currently, total hip arthroplasty is the most successful approach to treat end-stage hip disease, with the acetabular cup being an important component of the total hip system.

The current acetabular cup mainly comprises a lining and a backing material, wherein the lining can be made of metal, ceramic or high molecular materials, and most of the lining currently uses high molecular materials, such as ultrahigh molecular polyethylene (UHMWPE). Because the backing is contacted with the acetabulum of a human body, in order to avoid artificial total hip joint loosening, the backing is usually subjected to surface treatment at present, for example, titanium bead sintering or titanium alloy powder, biological ceramic powder, carbonyl apatite (HA) coating and the like are carried out on the surface of the backing, and although the surface treatment can relieve the loosening problem, the surface treatment HAs insufficient fusion with the bone tissue of the human body and still HAs poor stability. For this purpose, the back surface of the acetabulum is further modified by preparing a porous coating or mounting a porous material on the surface thereof, such as sprayed porous alumina for the backing in the american patent US20030050705 acetabulum cup, porocoat for the backing in the american patent US20020040245 Press fit acetabulum cup and dassociated method for curing the cup to an acetabulum, porous titanium for the backing material of the acetabulum cup produced by Biomet, inc, metal trabecula (porous tantalum) for the backing material of the acetabulum cup produced by Zimmer, porous titanium for the artificial acetabulum cup produced by patent CN 104840277a, etc. However, the porous materials used above are all materials with single pore, and the material with single pore has the disadvantage that the cavity wall of the pore is still a compact material, when the acetabular cup is implanted, when the acetabular cup is stressed, although the overall elastic modulus of the material is not high, the compact material used as the cavity wall has a large elastic modulus, so that cells on the cavity wall of the pore of the porous material are difficult to feel the stimulation of force, stress shielding occurs, the growth of the cells is not facilitated, tissues grow into the acetabular cup, and the fusion of the acetabular cup and surrounding bones is not facilitated, so that the interface between the acetabular cup and adjacent bone tissues is not firm, the loosening occurs, and the functional requirements of the artificial total hip joint replacement on the acetabular cup are difficult to meet.

The invention content is as follows:

the invention aims to provide an acetabular cup which is reasonable in structural design and can prevent loosening between an artificial hip joint and an acetabulum.

The purpose of the invention is realized by the following technical scheme:

an acetabular cup comprises a hemispherical lining, a backing and a porous material, wherein the porous material is arranged on the outer surface of the backing, and is a multi-level porous metal material; the hierarchical porous metal material has at least more than two hierarchical levels; the multi-level hole metal material is composed of all levels of hole cavities graded according to the size of the hole diameter of the material and all levels of cavity walls surrounding the formed hole cavities; the cavity wall which surrounds the upper large cavity in a three-dimensional space is made of a lower porous metal material; each stage of pore cavity is communicated with each other and each stage of pore cavity is also communicated with each other.

Furthermore, when the hierarchical level of the multi-level hole metal material is three, the aperture of the first-level pore cavity is a micron-level hole, the aperture of the third-level pore cavity is a nanometer-level hole, and the aperture of the second-level pore cavity is between the apertures of the first-level pore cavity and the third-level pore cavity.

Further, in the acetabular cup, the pore diameter of the smallest porous metal material in the multi-stage porous metal materials is less than 1 micron, the elastic modulus of the smallest porous metal material is less than 80GPa, and the porosity is preferably not less than 40%, wherein the porosity refers to the porosity of the material only in the stage pore cavity, and the smallest porous metal material is on the wall of the upper stage pore, so that the elastic modulus of the wall of the upper stage pore is less than that of the dense metal material.

Furthermore, in the acetabular cup and the multi-level porous metal material, the elastic modulus of the upper-level porous metal material which is one level larger than the smallest-level pore is preferably less than 50GPa, and the porosity is preferably not less than 55%, the elastic modulus of the cavity wall is smaller than that of the compact metal material due to the existence of the smallest-level pore on the cavity wall of the upper-level porous metal material, and in addition, the overall elastic modulus of the multi-level porous metal material is further reduced relative to that of the single upper-level porous material.

Furthermore, in the acetabular cup, the elastic modulus of the upper-level porous metal material which is two levels larger than the smallest-level pore cavity in the multi-level porous metal material is less than 12GPa, the porosity is preferably not less than 70%, and the elastic modulus value and the porosity value are combined with the existence of the lower two-level pores to be beneficial to bone tissue regeneration.

Furthermore, the overall elastic modulus of the multilevel-hole metal material of the acetabular cup is 1.5-5GPa, which is equivalent to that of animal cancellous bone, and thus, stress stimulation to cells on the acetabular cup is facilitated.

Further, the cavities of the same-grade porous metal material of each stage in the multi-stage porous metal material are uniformly distributed in the material body, so that the performance of the acetabular cup is uniform and consistent.

Further, the hierarchical porous metal material may be prepared using a variety of metal materials, for example: is prepared from medical titanium and alloy, medical niobium and alloy, medical tantalum and alloy, medical stainless steel, medical cobalt-based alloy and other materials.

The invention has the beneficial effects that:

(1) the invention provides an acetabulum cup, wherein a porous metal material with a multi-stage pore structure is arranged on the outer surface of a backing, a material body is composed of cavities graded according to the pore size of the material and cavity walls surrounding the formed cavities, the cavities of each stage of porous metal material are communicated with each other, and the cavities of each stage of porous metal material are also communicated with each other. Because the lower-level hole is arranged on the cavity wall of the upper-level cavity, the elastic modulus of the cavity is obviously reduced relative to a compact material, so that cells adhered to the cavity wall in the hole can feel the stimulation of stress, the stress shielding is avoided, the rapid growth of the cells is promoted, and the regeneration of bone tissues is accelerated; and because the connectivity is very good, and the upper hole of the cavity wall has capillary action, so that tissue fluid and metabolites can be quickly and fully transmitted, the tissue can smoothly grow, and can completely grow into the porous material, so that the close fusion of the acetabular cup and the adjacent bone tissue can be realized, and the relatively installed porous material acetabular cup with single pore can make the bone tissue quickly grow into the porous material positioned on the outer surface of the back of the acetabular cup, and can be quickly and tightly fused with the acetabular cup, so that the acetabular cup is firmly fixed on the acetabular cup, the problems of unstable interface and looseness are overcome, the repair of the hip joint is avoided, the pain of a patient is relieved, and the service life of the artificial hip joint is prolonged.

(2) According to the acetabular cup provided by the invention, the three-stage pore structure adopted by the porous metal material of the multi-stage pore structure arranged on the outer surface of the backing is particularly beneficial to bone tissue regeneration after the acetabular cup is arranged, the size of the first-stage pore cavity is beneficial to meeting the requirement of tissue ingrowth, the second-stage pore cavity is beneficial to inhabitation of various cells, and the third-stage pore cavity is beneficial to meeting the requirements of cell adhesion and differentiation.

(3) According to the acetabular cup provided by the invention, the elastic modulus and the porosity value of the porous metal material minimum-level hole, the upper-level hole of the minimum-level hole and the upper-level hole of the multi-level hole structure arranged on the outer surface of the backing are set, so that the elastic modulus of the cavity wall of the cavity is obviously reduced relative to that of a compact metal material, cells adhered to the cavity wall in the hole can sense stress stimulation, and the overall elastic modulus is equivalent to that of animal cancellous bone, so that the cells on the acetabular cup can obtain stress stimulation.

(4) The cavities of the same-grade porous metal material of each grade in the multi-grade porous metal material are uniformly distributed in the material body, so that the performance of the acetabular cup is uniform and consistent.

Drawings

The invention will be further elucidated with reference to the embodiments and drawings.

FIG. 1 is a schematic view of the acetabular cup of the invention, and FIG. 2 shows a structure for preparing a multi-level hole metal material on the acetabular cup.

Detailed Description

The following description will be made in conjunction with the accompanying drawings, which are provided to explain the embodiments of the present invention in detail and to explain the detailed embodiments and the specific operation procedures based on the technical solutions of the present invention, but the scope of the present invention is not limited to the following embodiments.

As shown in FIG. 1, 1 is an acetabular cup liner, 2 is a backing, and 3 is a porous material on the backing. Fig. 2 shows that the multi-level pore metal material is a two-level pore material, 4 is a large pore, 5 is the wall of the large pore, and 6 is a small pore on the wall of the large pore.

Example 1

The acetabular cup liner material in the embodiment is made of ultrahigh molecular polyethylene (UHMWPE), the backing is made of metal titanium, the porous material on the backing is made of a porous cobalt-based alloy material CoCrMo with a secondary pore structure, the pore size of uniformly distributed first-stage pore cavities is 120-400 mu m, the uniformly distributed second-stage pore cavities, namely the wall of the first-stage pore cavities, on the wall of the first-stage pore cavities are made of lower-stage porous metal materials formed by uniformly distributed second-stage pore cavities, the pore size of the second-stage pore cavities is 400-630 nm, the first-stage pore cavities and the second-stage pore cavities are communicated with each other, and the first-stage pore cavities and the second-stage pore cavities are also communicated with each other. The preparation method of the acetabular cup comprises the following steps:

(1) preparing a titanium backing blank by hot stamping, and then roughly processing to obtain a titanium backing rough processing blank;

(2) cobalt-based alloy CoCrMo powder with the particle size of 90nm-130nm, methylcellulose with the particle size of 480nm-730nm and polystyrene with the particle size of 480nm-730nm are mixed according to the proportion of cobalt-based alloy powder: methyl cellulose: polystyrene: distilled water is mixed according to the volume ratio of 1: 1.5: 1: 7.5 preparing slurry;

(3) adopting polyester foam with the edge diameter of 220-500 mu m, uniformly filling the slurry therein by using a foam impregnation method to form a blank body, drying, and crushing to obtain mixed particles containing the raw material, the pore-forming agent and the polyester foam, wherein the particles are 220-500 mu m.

(4) Preparing a concave spherical mold, wherein the size of the spherical surface of the concave spherical mold is matched with the outer diameter (including machining allowance) of the backing porous material, placing the titanium backing rough machining blank prepared in the first step on the concave spherical surface of the concave spherical mold, wherein the convex spherical surface of the titanium backing rough machining blank is opposite to the concave spherical surface of the mold, and a certain gap is reserved, and the thickness of the gap is the thickness of the porous material product plus the machining allowance;

(5) mixing the mixed particles prepared in the second step and ethyl cellulose with the particle size of 220-500 mu m according to a volume ratio of 1: 4, uniformly mixing and filling gaps between the titanium backing rough machining blank and the concave spherical surface die in the third step, compacting the titanium backing rough machining blank, and enabling the thickness of the gaps to be uniform; and then putting the two materials into a vacuum furnace for sintering, and then carrying out subsequent treatment and machining according to the conventional process of the cobalt-based alloy CoCrMo to obtain a combination of the backing and the multi-level hole cobalt-based alloy CoCrMo.

(6) And assembling the ultrahigh molecular weight polyethylene lining and the combined body in the fourth step to obtain the acetabular cup.

Preparing porous cobalt-base alloy CoCrMo only with primary pore cavities by a conventional foam impregnation method, wherein the distribution of pores is the same as that of the original porous cobalt-base alloy CoCrMo with secondary pores, the porosity is 73%, testing a compression stress-strain curve of the porous cobalt-base alloy sample by using an Instron mechanical testing machine, wherein the initial deformation displayed by the stress-strain curve is elastic deformation, the ratio of the stress value of the elastic deformation part to the corresponding strain value is taken as the elastic modulus, and the elastic modulus is measured to be 7.6 GPa.

And measuring the elastic modulus of the second-stage porous cobalt-based alloy CoCrMo material by using a nano indentation method, wherein the elastic modulus of the porous niobium cobalt-based alloy CoCrMo with the second-stage pore cavity is 57GPa, and the porosity of the second-stage porous cobalt-based alloy CoCrMo material is 53%.

An Instron mechanical testing machine is adopted to test that the overall elastic modulus of the porous cobalt-base alloy CoCrMo material with the secondary pore structure is 5 GPa.

Example 2:

an acetabular cup, wherein an acetabular cup lining material adopts polyether ether ketone (PEEK), a backing adopts metal niobium, a porous material on the backing adopts multi-level pore niobium, the multi-level pore niobium has a two-level pore structure, the pore size of a first-level pore cavity is 900 mu m-1500 mu m, the pore size of a second-level pore cavity is 400nm-700nm, and the structure and the preparation method are similar to those of embodiment 1.

The porosity of the first-stage pores of the porous niobium is 80%, the elastic modulus is 3.2GPa, the porosity of the second-stage pores is 41%, the elastic modulus is 79GPa, and the overall elastic modulus is 2.7 GPa.

Example 3:

the acetabular cup liner material of the embodiment adopts ultrahigh molecular polyethylene (UHMWPE), the backing adopts metal titanium, the porous material on the backing adopts multi-level pore tantalum, and the multi-level pore tantalum has a three-level pore structure, wherein uniformly distributed and mutually communicated second-level pores are arranged on the wall of a first-level pore cavity (namely a maximum-level pore cavity), and uniformly distributed and mutually communicated third-level pore cavities (namely a minimum-level pore cavity) are arranged on the wall of a second-level pore cavity; and the pore cavities of all stages are communicated with each other. The aperture of the first-stage cavity is 460-620 mu m, the porosity is 88%, the aperture of the second-stage cavity is 48-80 mu m, the porosity is 73%, the aperture of the third-stage cavity is 340-480 nm, and the porosity is 62%. The preparation method of the acetabular cup comprises the following steps:

(2) tantalum powder with the average particle size of 40nm is used as a raw material, starch with the particle size of 420nm-580nm is used as a pore-forming agent of the smallest primary pore cavity of porous tantalum to be prepared, stearic acid with the particle size of 420nm-580nm is used as a bonding agent, and the following steps are carried out according to the weight ratio of the tantalum powder: starch: stearic acid: distilled water is mixed according to the volume ratio of 1: 4: 1: 11 preparing slurry; uniformly filling the slurry into polyester foam with the aperture of 500-800 mu m by a foam impregnation method to form a blank body, drying, and crushing to obtain mixed particles containing the raw material, the pore-forming agent and the polyester foam, wherein the particles are 56-90 mu m;

(3) preparing a three-dimensional through polyester foam body according to the shape and the size of a porous material on a lining, wherein the diameter of a ridge is 550-720 mu m, the pore size is 600-820 mu m, the size of the foam body is reserved in a closed die for compression amount and subsequent machining allowance, and mixing particles and ammonium chloride with the particle size of 56-90 mu m are mixed according to a volume ratio of 1: 4, uniformly mixing the mixture fully and uniformly, then uniformly filling the mixture into the polyester foam, and then placing the polyester foam into a closed mold to be pressed into a compact blank;

(4) vacuum sintering the compact blank, carrying out conventional subsequent heat treatment on the sintered blank according to a tantalum material process to obtain a multi-level hole tantalum blank with a three-level hole structure, and then carrying out rough machining, wherein the size of the concave spherical surface of the multi-level hole tantalum blank is matched with that of the convex spherical surface of the rough machining blank of the titanium backing prepared in the first step;

(5) and (3) connecting the rough machined blank of the titanium backing prepared in the first step and the multi-stage hole tantalum blank machined in the fourth step together by using a vacuum brazing process, and then carrying out subsequent machining to obtain a combination of the backing and the multi-stage hole tantalum.

(6) And (5) assembling the ultrahigh molecular weight polyethylene lining and the combined body in the step (5) together to obtain the acetabular cup.

The porosity of the multilevel pore tantalum material for the acetabular cup is tested by a section direct observation method, and the result is as follows: the porosity of the primary pores is 88%, and the porosity refers to the porosity of the material with only primary pores, namely, the secondary and tertiary pores are not counted in calculation (the secondary and tertiary pores are regarded as compact entities). The porosity of the third stage pore is 62%, the porosity is the porosity of the material with only the third stage pore, namely, during calculation, the material part with only the third stage pore is taken for analysis and calculation, the porosity of the second stage pore is 73%, the porosity is the porosity of the material with only the second stage pore, namely, during calculation, the material part with only the second stage pore and the third stage pore is taken for calculation, but the third stage pore is not counted, and the material is taken as a compact entity.

And measuring the elastic modulus of the second-stage porous tantalum material and the third-stage porous tantalum material by using a nano indentation method, wherein the elastic modulus of the porous tantalum with the second-stage cavities is 30GPa, and the elastic modulus of the porous tantalum with the third-stage cavities is 57 GPa.

Preparing the porous tantalum only with the primary pore cavity by using a conventional foam impregnation method, testing a compression stress-strain curve of the porous tantalum sample by using an Instron mechanical testing machine, wherein the initial deformation displayed by the stress-strain curve is elastic deformation, taking the ratio of the stress value of the elastic deformation part to the corresponding strain value as the elastic modulus, and measuring the elastic modulus to be 2.1 GPa.

The overall elastic modulus of the porous tantalum with the three-stage pore cavity structure is measured to be 1.5GPa by the same test method.

The inventor carries out implantation tests on the goat hind leg hip joints by using the acetabular cups, and the results show that after the acetabular cup is implanted for 14 weeks, tissues completely grow into the multi-level hole material, the acetabular cup is tightly fused with surrounding bone tissues, the interface is stable, and the phenomenon of looseness is avoided.

Claims

1. An acetabular cup, includes hemisphere inside lining, back backing and porous material, and porous material sets up in back backing surface, its characterized in that: the porous material is a hierarchical porous metal material; the hierarchical porous metal material has at least more than two hierarchical levels; the multi-level hole metal material is composed of all levels of hole cavities graded according to the size of the hole diameter of the material and all levels of cavity walls surrounding the formed hole cavities; the cavity wall which surrounds the upper large cavity in a three-dimensional space is made of a lower porous metal material; each stage of pore cavity is communicated with each other and each stage of pore cavity is also communicated with each other.

2. The acetabular cup of claim 1, wherein: when the grading level of the multi-level hole metal material is three, the aperture of the first-level pore cavity is a micron-level hole, the aperture of the third-level pore cavity is a nanometer-level hole, and the aperture of the second-level pore cavity is between the apertures of the first-level pore cavity and the third-level pore cavity.

3. The acetabular cup of claim 1, wherein: the pore diameter of the minimum-grade porous metal material in the multi-grade porous metal material is less than 1 micron, the elastic modulus of the minimum-grade porous metal material is less than 80GPa, and the porosity is not less than 40%.

4. The acetabular cup of claim 2, wherein: the elastic modulus of the minimum-grade porous metal material in the multi-grade porous metal materials is below 80GPa, and the porosity is not less than 40%.

5. The acetabular cup of any one of claims 1 to 4, wherein: in the multi-stage porous metal material, the elastic modulus of the upper-stage porous metal material which is one stage larger than the smallest-stage pore space is less than 50GPa, and the porosity is not less than 55%.

6. The acetabular cup of any one of claims 1 to 4, wherein: in the multi-stage porous metal material, the elastic modulus of the upper-stage porous metal material which is two stages larger than the minimum-stage pore space is less than 12GPa, and the porosity is not less than 70%.

7. The acetabular cup of claim 5, wherein: in the multi-stage porous metal material, the elastic modulus of the upper-stage porous metal material which is two stages larger than the minimum-stage pore space is less than 12GPa, and the porosity is not less than 70%.

8. The acetabular cup of any one of claims 1 to 4 or 7, wherein: the integral elastic modulus of the hierarchical pore metal material is 1.5-5 GPa.

9. The acetabular cup of any one of claims 1 to 4 or 7, wherein: the cavities of the same-level porous metal material of each level in the multi-level porous metal material are uniformly distributed in the material body.

10. The acetabular cup of any one of claims 1 to 4 or 7, wherein: the hierarchical pore metal material is prepared from medical titanium and alloy, medical niobium and alloy, medical tantalum and alloy, medical stainless steel or/and medical cobalt-based alloy.