JP3176176B2 - Artificial cartilage and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art At present, a total replacement type artificial joint that replaces the entire joint is used even for partial articular cartilage damage. However, an artificial joint cartilage that can replace only the articular cartilage is not suitable for a living body. With less invasiveness and the possibility of avoiding problems such as destruction of the surrounding bone tissue commonly found in artificial joints, studies have been actively conducted.

[0003] Among them, the invention of Japanese Patent Application Laid-Open No. 3-141957 discloses a method of combining a polyvinyl alcohol (hereinafter abbreviated as PVA) hydrogel having excellent sliding characteristics and a suitable elastic modulus with a porous alumina ceramic or metal mesh. The present invention relates to an artificial cartilage comprising: a porous alumina ceramic or metal mesh; A method has been adopted in which a resin material is impregnated in advance and the resin is removed after gelation of PVA.

[0004]

However, in the above prior art,
It is troublesome to manufacture because PVA requires a step of removing the resin after gelation, and it is difficult to accurately control the impregnated region when impregnating the resin. There has been a disadvantage that the most suitable area cannot be secured, or the resin is impregnated into an area necessary for the PVA hydrogel to be firmly bonded.

[0005] Furthermore, the new bone grown and grown in the porous alumina ceramics or metal mesh eventually becomes PV
A comes into direct contact with the hydrogel, but this PVA hydrogel has a slight stimulus to new bone unlike alumina ceramics or titanium,
The surrounding bone tissue could be adversely affected.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a water-containing polyvinyl alcohol gel on one of the above-mentioned fiber meshes constituting a metal triple structure in which fiber meshes are fixed on both sides of a metal foil. To provide an artificial joint cartilage characterized in that an outer surface of a polyvinyl alcohol hydrogel is formed by impregnating and fixing the same.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Configuration FIG. 1 illustrates a femoral head resurfacing prosthesis cartilage 1 for use in the hip joint portion of the human, the artificial articular cartilage 1, titanium, titanium alloy, stainless steel, Co chromatography Cr alloy, zirconium, platinum, gold, One of the fiber meshes 3 and 4 constituting the triple structure 5 in which the fiber meshes 3 and 4 made of the metal material are fixed on both sides of the metal foil 2 made of a metal material having no biological harm such as silver. The outer surface 7 of the PVA hydrogel is formed by impregnating and fixing the PVA hydrogel 6 to the (fiber mesh 4). A beam-like projection 3a is formed on the fiber mesh 3 on the side fixed to the bone so as to reinforce the engaging force with the bone A as shown in FIG.

FIGS. 3, 4 and 5 show an acetabular surface replacement artificial cartilage 1, a tibia surface replacement artificial cartilage 1 and a human intervertebral disc B as examples of the present invention, respectively. FIG. 6 shows a state in which the disc B of the human body is replaced with the artificial cartilage 1 in FIG.

[0009] The artificial joint cartilage 1 constructed as described above.
Is a region most suitable for the growth and growth of bone using the metal foil 2 as a partition, ie, the fiber mesh 3 and PVA.
The fiber mesh 4, which is an area necessary for the hydrogel to be firmly bonded, can be designed and secured in advance.

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

[0011] From the above, PV is stable in vivo,
Since the outer surface 7 of the hydrogel A is formed, the sliding properties are excellent, and since the hydrogel 6 has a suitable elastic modulus, ideal stress transmission can be performed.

Manufacturing Method Next, a manufacturing method of the artificial joint cartilage 1 will be described below. In the following description, the method for preparing the PVA solution and the method for gelling are based on the method of the invention of JP-A-3-141957. First, fibers made of a metal material having no harm to the living body are press-molded to obtain two fiber meshes 3 and 4. At this time, even if the porosity of these fiber meshes 3 and 4 is the same,
The fiber mesh 3 on the side fixed to the bone may be different, and the porosity suitable for promoting the growth and growth of bone is selected, while the fiber mesh 4 on the side fixing the hydrogel 6 containing PVA is made of PVA. The porosity may be selected so that the hydrogel 6 can be fixed with sufficient strength.

Then, the fiber meshes 3, 4
The metal foil 2 made of a metal material having no harm to the living body is sandwiched between the two, and this is heated in a vacuum or in an inert atmosphere (during a holding time of about 3 hours) to be diffused and bonded. A structure was obtained.

Next, after covering the surface of the triple-structured fiber mesh 3 with a silicone rubber (not shown) having plasticity, the fiber mesh 4 is placed in a suitable molding container with the fiber mesh 4 facing upward. installed.

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

Thereafter, the molding container is cooled to -20 ° C. to gel the PVA, and after returning to room temperature, the solvent is removed from the PVA by immersion in ethanol, and then the PVA is dried by a vacuum drying method. The ethanol in was removed.

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

As described above, the artificial cartilage 1 was obtained. FIG. 7 shows a split-type molding container 8 used for producing the tibial surface-replacement type artificial cartilage according to the embodiment of the present invention. In FIG. Container.

Experimental Example Next, 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 5 × 5 × 7 mm fiber mesh was formed from a titanium fiber as a metal linear body by a metal mold press. At this time, by adjusting the amount of titanium fiber to be filled in the mold, the porosity is reduced to 40.
%, 50%, 60%, and 70% fiber meshes were prepared for each of the four types. Subsequently, a titanium metal foil sandwiched between these fiber meshes was subjected to diffusion bonding by heat treatment at 1300 ° C. for 3 hours under vacuum to obtain a triple structure as a test body.

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

[0022]

[Table 1]

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

Similarly, a set of four types of cylindrical fiber meshes each having a diameter of 5 mm and a length of 50 mm was prepared for each of four types, and a titanium metal foil was sandwiched between these fiber meshes at 1,300 ° C. under vacuum. And diffusion bonding was performed by heat treatment for 3 hours to obtain four triple structures.

Subsequently, using the method of the above embodiment, a PVA hydrogel was fixed to one side of each triple structure, and the diameter was 4 mm.
A portion having a height of 5 mm and composed only of the PVA hydrogel was added to obtain four test specimens.

In order to measure the bonding strength between the PVA hydrogel and the fiber mesh of these test specimens, a shear force parallel to the interface between the portion composed of only the PVA hydrogel and the fiber mesh is applied to cause breakage. The shear stress at that time was determined. Table 2 shows the results.

[0027]

[Table 2]

As apparent from Table 2, the above shear strength is proportional to the porosity. That is, as the porosity decreases, the shear strength tends to decrease, but when the porosity is 35%, the shear strength is 0.05 MPa, so the mechanical strength is insufficient, and the viewpoint of the shear strength of the PVA hydrogel is low. The porosity of the fiber mesh is 40%
It has been found that the above is preferable.

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

[0030]

As described above, in the artificial joint cartilage of the present invention, one of the fiber meshes constituting the metal triple structure in which the fiber mesh is fixed to both sides of the metal foil is impregnated with a hydrogel of polyvinyl alcohol. Since the outer surface of the polyvinyl alcohol hydrogel is formed by fixing, the area most suitable for the growth and growth of bone and the area necessary for the PVA hydrogel to be firmly bonded to each other by using the metal foil as a partition. Can be designed and secured in advance.

Further, the new bone grown and grown in the fiber mesh is directly converted into PVA by the partition of the metal foil.
Since there is no irritating problem that may occur when contacting the hydrogel, it does not adversely affect the surrounding bone tissue.

As described above, the artificial joint cartilage is stable in a living body, has excellent sliding characteristics, and has a suitable elastic modulus, and can transmit ideal stress.

Further, the method for producing an artificial joint cartilage of the present invention does not require a troublesome step of removing a resin material in the process of impregnating and fixing PVA gel, so that it is simple and advantageous in cost. .

[Brief description of the drawings]

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

FIG. 2 is a side view showing the artificial joint cartilage of FIG. 1 in which the surface of a femur has been replaced.

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

FIG. 4 is a sectional view of the tibial surface replacement type artificial cartilage according to the 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 a human intervertebral disc.

6 is a side view showing the artificial joint cartilage of FIG. 5 in which a human intervertebral disc has been replaced.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Artificial articular cartilage 2 Metal foil 3 Fiber mesh 4 Fiber mesh 5 Triple structure 6 PVA hydrogel 7 Outer surface 8 Molding container 3a Beam-shaped protrusion 8a Upper container 8b Lower container A Bone disc

────────────────────────────────────────────────── ─── of the front page continued (72) inventor Yasuo Nakajima Shiga Prefecture Gamo-gun Kamou Kawai address 10 of 1 Kyocera Corporation Shiga factory examiner HiroshiMinoru Kenji (58) investigated the field (Int.Cl. ^7, DB name) A61F 2/28 A61L 27/00 WPI (DIALOG)

Claims (2)

(57) [Claims] To 1. A both side surfaces of the metal foil made Ri by a metallic material without damage resistance for biological, an artificial articular cartilage made by fixing the fiber mesh made of the metallic material, polyvinyl alcohol water to one of the fiber mesh An artificial joint cartilage characterized by being impregnated and fixed with a gel and having an outer surface of a polyvinyl alcohol hydrogel. 2. A fiber mesh made of a metal material made of a metal material having no harm to living organisms is fixed by diffusion bonding to both side surfaces of a metal foil made of a metal material which is not harmful to the living body at a high temperature and in a vacuum or in an inert atmosphere. A method for producing an artificial joint cartilage, wherein one of the meshes is impregnated with a hydrogel of polyvinyl alcohol to form an outer surface of the hydrogel of polyvinyl alcohol.