JPH06339490A - Artificial articular cartilage and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an artificial articular cartilage having an excellent sliding characteristic and a suitable modulus of elasticity by securing fiber meshes on both sides of metal foil harmless to living tissue, and impregnating one of the fiber meshes with a polyvinyl alcohol water-bearing gel. CONSTITUTION:This artificial articular cartilage 1 of a type which replaces the surface of the head of the femur, etc., has a triple structure 5 comprising fiber meshes 3, 4 secured to both sides of foil 2 of a metal harmless to living tissue, such as titanium, a titanium alloy, stainless steel, a Co-Cr alloy, zirconium platinum, gold or silver, each of the fiber meshes 3, 4 being made of a similar metal. One of the fiber meshes (4) has an outer surface 7 of PVA(polyvinyl alcohol) water-bearing gel which is formed by impregnating the mesh with a PVA water-bearing gel 6. Beam-like protrusions are formed on the fiber mesh 3 secured to the bone, to increase the force of adhesion to the bone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to artificial joint cartilage replacing natural articular cartilage and a method for producing the same.

[0002]

2. Description of the Related Art Currently, even in the case of partial cartilage damage, a total replacement type artificial joint that replaces the entire joint is used. It is considered that it is less invasive and can avoid problems such as destruction of surrounding bone tissue, which is generally found in artificial joints, and the research has been actively conducted.

Among them, the invention of JP-A-3-141957 is a combination of a polyvinyl alcohol (hereinafter abbreviated as PVA) hydrogel having excellent sliding properties and a suitable elastic modulus and porous alumina ceramics or a metal mesh. The present invention relates to an artificial joint cartilage, and in the present invention, in order to secure a region for proliferating and growing bone instead of impregnating and fixing PVA gel in a part of pores of porous alumina ceramics or metal mesh, a desired region A method has been adopted in which the resin material is impregnated in advance and the resin is removed after gelation of PVA.

[0004]

However, in the above-mentioned prior art,
It is troublesome to produce because the step of removing the resin is necessary after gelation of PVA, and it is difficult to accurately control the impregnated area when impregnating the resin, but due to bone growth and growth. There is a disadvantage that the most suitable region cannot be secured, or the resin is impregnated into a region necessary for the PVA hydrogel to firmly bond.

Furthermore, the new bone grown and grown in the porous alumina ceramics or the metal mesh eventually becomes PV.
Although it comes into direct contact with the hydrogel A, this PVA hydrogel has a slight stimulating effect on new bone, unlike alumina ceramics or titanium.
There was a risk of adversely affecting the surrounding bone tissue.

[0006]

In order to solve the above-mentioned problems, the present invention provides a polyvinyl alcohol hydrogel on one side of the above-mentioned fiber mesh which constitutes a metal triple structure in which fiber mesh is fixed on both sides of a metal foil. Provided is an artificial joint cartilage characterized in that the outer surface of a polyvinyl alcohol hydrogel is formed by impregnating and fixing the artificial joint cartilage and a method for producing the same.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. Configuration FIG. 1 shows a femoral head surface replacement type artificial joint cartilage 1 used for a human hip joint part. This artificial joint cartilage 1 is made of titanium, titanium alloy, stainless steel, Co-Cr alloy, zirconium, platinum, gold, One of the above-mentioned fiber meshes 3 and 4 constituting a triple structure 5 in which fiber meshes 3 and 4 made of the metal material are fixed on both sides of a metal foil 2 made of a metal material such as silver that is not harmful to the living body. An outer surface 7 of the PVA hydrous gel is formed by impregnating and fixing the PVA hydrous gel 6 in the (fiber mesh 4). A beam-shaped projection 3a is formed on the fiber mesh 3 on the side fixed to the bone to reinforce the engagement force with the bone A as shown in FIG.

In FIGS. 3, 4 and 5, the acetabular surface-replacement type artificial joint cartilage 1, the tibia side surface-replacement type artificial joint cartilage 1 and the intervertebral disc B of the human body are respectively replaced as examples of the present invention. FIG. 6 shows an artificial joint cartilage 1 for doing this, and FIG. 6 shows a state where the intervertebral disc B of the human body is replaced with the artificial joint cartilage 1 of FIG.

The artificial joint cartilage 1 constructed in this way
Is a region most suitable for the growth and growth of bone with the metal foil 2 as a partition, that is, the fiber mesh 3 and PVA.
The fiber mesh 4 which is a region necessary for the water-containing gel to firmly bond can be designed and secured in advance.

Further, by the partition of the metal foil 2,
The new bone that has grown and grown in the fiber mesh 3 is directly
Since the problem of irritation which is a concern when contacting the VA hydrous gel 6 does not occur, it does not adversely affect the surrounding bone tissue.

From the above, PV is stable in vivo and PV
Since the outer surface 7 of the water-containing gel A is formed, the sliding property is excellent, and since the PVA water-containing gel 6 has a suitable elastic modulus, ideal stress transmission can be performed.

Manufacturing Method Next, a method of manufacturing the artificial joint cartilage 1 will be described below. In the following description, the PVA solution preparation method and gelation method are based on the method of the invention of JP-A-3-141957. First, the fibers made of a metal material that is not harmful to the living body are press-molded to obtain two fiber meshes 3 and 4. At this time, even if the porosities of these fiber meshes 3 and 4 are the same,
The fiber mesh 3 on the side fixed to the bone may have a porosity suitable for promoting the proliferation and growth of the bone. On the other hand, the fiber mesh 4 on the side fixing the PVA hydrogel 6 may be PVA. The porosity may be selected so that the hydrous gel 6 can be fixed with sufficient strength.

After that, the fiber meshes 3 and 4 are
A metal foil 2 made of a metal material that is not harmful to living organisms is sandwiched between the two, and this is heated in a vacuum or in an inert atmosphere (holding time about 3 hours) to perform diffusion bonding, and the triple layer is formed. The structure was obtained.

Next, the surface of the fiber mesh 3 of the triple structure is covered with a silicone rubber (not shown) having plasticity, and then the fiber mesh 4 is placed in an appropriate molding container with the fiber mesh 4 on top. installed.

Further, water: dimethyl sulfoxide =
A PVA solution adjusted to a concentration of 10% in a mixed solvent of 2: 8 at about 100 ° C. was poured into the container to impregnate only the fiber mesh 4 with the PVA solution.

Thereafter, the above-mentioned molding container is cooled to -20 ° C. to gelate PVA, and then the solvent is removed from the PVA by immersing it in ethanol after returning it to room temperature, and then the PVA is vacuum dried. The ethanol inside was removed.

Finally, the PV is obtained by cutting and polishing.
The shape of A was adjusted and immersed in pure water at about 37 ° C. for 48 hours or more.

The above artificial joint cartilage 1 was obtained as described above. In addition, FIG. 7 shows a split-type molding container 8 used in manufacturing the above-described tibial surface replacement type artificial joint cartilage according to the embodiment of the present invention. It is a container.

Experimental Example Next, in order to confirm the mechanical properties of the artificial joint cartilage according to the present invention, the compressive strength of the fiber mesh and the fixing force between the PVA hydrogel and the fiber mesh were measured. The experiment will be described below.

First, a metal fiber-shaped titanium fiber was molded into a fiber mesh of 5 × 5 × 7 mm by a die press. At this time, the porosity was adjusted to 40 by adjusting the amount of titanium fiber filled in the mold.
%, 50%, 60%, and 70% fiber mesh were prepared for each set of four types. Subsequently, a metal foil made of titanium sandwiched between these fiber meshes was diffusion-bonded by a heat treatment under vacuum at 1300 ° C. for 3 hours to obtain a triple structure as a test body.

The results of measuring the compressive strength (compressive stress at the yield point) of these test bodies are shown in Table 1.

[0022]

[Table 1]

As is clear from Table 1, the compressive strength is inversely proportional to the porosity, but at 85%, it is 0.10 MPa.
And the mechanical strength is insufficient, while 30
% Cannot be manufactured by ordinary press molding. Therefore, from the viewpoint of compressive strength, it was found that the porosity of the fiber mesh is preferably 40% to 70%.

Similarly, four sets of cylindrical fiber meshes each having a diameter of 5 mm and a length of 50 mm were prepared, one set each, and a metal foil made of titanium was sandwiched between these fiber meshes under vacuum at 1300 ° C. After that, diffusion bonding was performed by heat treatment for 3 hours to obtain four triple-layered structures.

Then, using the method of the above-mentioned embodiment, a PVA hydrogel was fixed on one side of each triple structure, and the diameter was 4 mm.
A portion having a height of 5 mm and composed only of PVA hydrous gel was added to obtain four test bodies.

In order to measure the bonding force between the PVA hydrogel and the fiber mesh of these test bodies, shearing force parallel to the interface between the fiber mesh and the portion composed only of the PVA hydrogel is applied to cause fracture. The shear stress at that time was determined. The results are shown in Table 2.

[0027]

[Table 2]

As is clear from Table 2, the shear strength is proportional to the porosity. That is, although the shear strength tends to decrease as the porosity decreases, the mechanical strength is insufficient because the shear strength becomes 0.05 MPa at the porosity of 35%, and the shear strength of the PVA hydrous gel is considered. From the above, the porosity of the fiber mesh is 40%.
It has been found that the above is preferable.

From the above, the porosity of the fiber mesh forming the artificial joint cartilage of the present invention is 40% to 70%.
Is preferred.

[0030]

As described above, the artificial joint cartilage of the present invention is impregnated with polyvinyl alcohol hydrogel in one side of the above-mentioned fiber mesh which constitutes a metal triple structure in which fiber mesh is fixed on both sides of a metal foil. Since the outer surface of the polyvinyl alcohol hydrogel is formed by fixing, the region most suitable for the growth and growth of bone with the metal foil as a partition and the region necessary for firmly bonding the PVA hydrogel. Can be designed and secured in advance.

Furthermore, by the partition of the metal foil, the new bone that has grown and grown in the fiber mesh is directly PVA.
Since the problem of irritation which is a concern when contacting the hydrogel does not occur, it does not adversely affect the surrounding bone tissue.

From the above, the artificial joint cartilage is capable of performing ideal stress transmission because it is stable in a living body, has excellent sliding characteristics, and has a suitable elastic modulus.

The method for producing artificial joint cartilage of the present invention is simple and cost-effective because it does not require a troublesome process such as removing the resin material in the process of impregnating and fixing the PVA gel. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a femoral surface replacement artificial joint cartilage according to an embodiment of the present invention.

FIG. 2 is a side view showing the artificial joint cartilage of FIG. 1 with the surface of the femur replaced.

FIG. 3 is a cross-sectional view of an acetabular surface replacement type artificial joint cartilage according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a tibial surface replacement type artificial joint cartilage according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of an artificial joint cartilage according to an embodiment of the present invention for replacing an intervertebral disc of a human body.

FIG. 6 is a side view showing the artificial joint cartilage of FIG. 5 with the intervertebral disc of the human body replaced.

FIG. 7 is a cross-sectional view showing a molding container used in producing the artificial joint cartilage of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Artificial joint cartilage 2 Metal foil 3 Fiber mesh 4 Fiber mesh 5 Triple structure 6 PVA hydrogel 7 Outer surface 8 Molding container 3a Beam-like projection 8a Container upper part 8b Container lower part A Bone B Intervertebral disc

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunori Tamura 1 at 10 Kawai, Gamo-cho, Gamo-gun, Shiga Prefecture Inside Kyocera Corporation's Shiga factory (72) Inventor Yu Ichinomiya, 10-go, Kawai, Gamo-cho, Gamo-gun 1 Kyocera Co., Ltd. Shiga Factory (72) Inventor Yasuo Nakajima 1 at 10 Kawai, Kamo-cho, Gamo-gun, Shiga Prefecture Kyocera Co., Ltd. Shiga Factory

Claims (2)

[Claims] 1. An artificial joint cartilage in which a fiber mesh made of a metal material is fixed on both sides of a metal foil made of a metal material which is not harmful to human body, and polyvinyl alcohol hydrogel is provided on one side of the fiber mesh. An artificial joint cartilage characterized by being impregnated and fixed with and having an outer surface of a polyvinyl alcohol hydrogel. 2. A fiber mesh made of the metal material is fixed on both sides of a metal foil made of a metal material which is not harmful to the body by diffusion bonding at high temperature under vacuum or in an inert atmosphere, and then the fiber is formed. A method for producing artificial joint cartilage, which comprises impregnating and fixing a polyvinyl alcohol hydrogel on one side of a mesh to form an outer surface of the polyvinyl alcohol hydrogel.