JPS596047A - Artificial joint - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an artificial joint for artificially repairing a joint of a living body and repairing its function and form.

When joint function is impaired due to trauma such as a traffic accident or joint pathology due to bone deformation such as rheumatism, and there is little hope for healing or recovery, replacement surgery involves removing the joint and replacing it with an artificial joint. is being carried out.

Such an artificial joint is required to have the following characteristics. (1) Because it is implanted in the body for a long period of time, it has excellent compatibility with surrounding tissues. (2) Alteration/transformation in the living body
No degeneration and no change in mechanical properties such as mechanical strength. (
3) The sliding part has excellent wear resistance and can perform basic joint functions. In particular, the mechanical strength of the bone insertion part is an important factor.The reason for this is that in addition to the weight of the living body, the muscular strength acting on the joints can exert a force that is several times the weight of the living body depending on the part. Therefore, great mechanical strength is required.

For this reason, in conventional artificial joints, as shown in Fig. 1, the femoral head ball member 3 made of alumina porcelain is used as the stem l inserted into the bone Bi, which is made of nickel-chromium alloy steel or cobalt-chromium alloy.
A socket made of high-density polyethylene and fixed with bone cement was fixed to the ilium Bλ, which was joined with molybdenum alloy permanent steel or the like and slidably rotated with the femoral head ball member 3. However, because the alumina porcelain femoral ball member and the high-density polyethylene socket were sliding, the inner surface of the high-density polyethylene socket wore out at a rate of about 0.2 tss per year, causing the problem that it had to be replaced every 3 years. . Furthermore, metal stem V is bone cemented so that it does not come into direct contact with bone B/! However, if it is implanted in the bone for a long period of time, it will undergo chemical changes together with the metal stem and become harmful to living organisms.

By the way, alumina ceramic is not harmful to living organisms and has a high mechanical strength compared to porcelain, so it can be considered to be used in place of a metal stem, but compared to a metal stem, it lacks mechanical strength, especially transverse rupture strength. There was a risk of breakage when the living body was subjected to large stress during exercise.

The present invention has been made to solve the above-mentioned drawbacks.
A socket having an exposed spherical inner surface made of sialumina porcelain made of alumina porcelain having an outer surface coated with calcium phosphate, a femoral ball member made of dense silicon nitride porcelain that rotatably slides on the spherical inner surface of the socket, and Connecting to the femoral ball member. The present invention provides an artificial joint comprising a stem made of metal and having a coating layer of calcium phosphate on the outer surface.

In the present invention, polycrystalline alumina porcelain was selected for the socket because it has significantly higher abrasion resistance than the conventionally used high-density polyethylene and alumina single crystal, and has no directionality in wear, making it more compatible with living organisms. This is because it is compatible with the bone tissue and is not harmful to the living body by threading the outer surface of the iliac bone B-2 and the socket) // and can be attached to the bone tissue without causing any harm to the living body. Calcium phosphate 12 on the outer surface
The reason why it is coated with calcium phosphate is that calcium phosphate has a higher affinity with human bone than similar components, and alumina porcelain also has a much better bonding ability with bone tissue. In addition, the spherical inner surface that slides on the femoral head ball member has extremely high wear resistance compared to high-density polyethylene, so there is no need to replace it. In addition, the reason why the femoral head ball member is made of high-density silicon nitride is that this material has an extremely fine fibrous structure, so it has extremely high mechanical strength, with a transverse rupture strength of / 00
Kg/71 or more, reaching 1zoKf shoulder, and there is no fear of cracking, so the conventional diameter, which was 26 intervals, can be reduced to 22 mm, and the socket can also be made smaller, which makes production easier and It has the great advantage of being inexpensive and reducing the burden on other living organisms. The alumina porcelain of the socket and the silicon nitride porcelain of the femoral head are extremely wear resistant because the silicon nitride has a fibrous structure, which not only extends the replacement period but also eliminates harmful wear particles. Next is the stem/
The reason why high-strength metal, especially non-ferrous steel, is used for the stem is because this stem requires great mechanical strength, and alumina porcelain or stabilized zirconia porcelain lacks strength and is prone to breakage. The reason why the calcium coating layer 16 is provided is that calcium phosphate has an extremely high affinity with bone Bt and has a high bonding ability with the stone implanted in the bone. In addition, calcium phosphate is gradually replaced by bone through long-term contact with bone, and eventually comes into contact with high-strength metal. Therefore, the surface of high-strength metal is coated with shell metal and is not made of ceramic or glass materials other than calcium phosphate. More preferably, it is coated with a resin.

In addition, the outer surfaces of the socket and stem should be smooth and have porous surfaces with pores of 20 to 200 microns in order to better blend in with the bone tissue and ensure firm adhesion.

An example of the manufacturing method will be specifically explained below. Commercially available high purity A
I! os 91% by weight (hereinafter "weight" will be omitted) MgO,
A diameter of 4'QIr was made using a well-known method using a substrate containing 1% CaO.
Make a cylinder with a length of J4m+, with a diameter of - in the center of the bottom.
A hemispherical recess with a length of 24.41 m was drilled, and a screw with a pitch/jl11 was provided on the side surface that was in contact with the other bottom side.
and sintering until the specific gravity becomes j, I j.

Next, CaC0a J OKg and PxOs/4'h were mixed and calcined at 1300° C. for several hours to form a semi-molten state, producing a mixture of calcium phosphate glass and crystals. The atomic ratio of Ca/P in this case is about 1. This was pulverized using a trommel so that particles of jμ or less were ≠Q%. This was added to water in which 1% of methylcellulose was dissolved and stirred to form a slurry of calcium phosphate.

Next, add YgOs to the 513N4 powder, which contains 70% d -Si3N4 and has an average particle size of 3μ or less! Using a rubber press, use a rubber press to make a recess /j as shown in Figure 1 in a part of the base material with a diameter of 24#. This is baked at 17θ0°C for 30 minutes in nitrogen to produce a femoral head.

Next, nickel-chromium alloy steel and cobalt-chromium
The stem≠ is made of molybdenum alloy inert steel, and the surface is roughened by sandblasting 2 strokes, and the socket 11 and stem/4I are made.
The above calcium phosphate slurry was applied with a brush to the outer surface not embedded in the femoral head, dried, and baked at 700° C. in the atmosphere to form a calcium phosphate coating layer on the surface.

Next, the stem was cooled to -70°C, inserted into the hole IS of the silicon nitride femoral head, and was able to be firmly cold-tightly joined. The stem and the femoral head may be joined with an adhesive such as polyethylene.

Since this part does not appear on the surface of the artificial bone, there is little harm to the living body.

Yet another method is to mix 70 to ≠θ% of organic powder or carbon powder, which is burnt off during firing with a particle size of 2 (7-tθθμ), into a slurry of calcilamnophosphate, and apply it to the outer surface of the socket and the femoral ball of the stem. If the outer surface that is not bonded is coated with the calcium phosphate coating layer before or after the above-mentioned coating layer and fired in the atmosphere, the organic matter and residual carbon and carbon powder will be burned out as carbon oxide gas, resulting in a 20 to 200μ It has pores.

Another method is to plate the surface of the nickel-free stainless steel or cobalt-chromium-molybdenum alloy steel with a noble metal such as gold plating, or to apply a coating layer of ceramic or glass other than calcium phosphate using a primer or flame spraying. Alternatively, it can be applied by chemical vapor deposition, physical vapor deposition, etc. In this case, during extremely long-term implantation, the calcium phosphate coating layer is replaced by the bone, and even if there is a final direct contact between the bone and the base metal, the presence of the precious metal plating layer or the ceramic layer makes it difficult to connect the bone to the bone. The negative effects that occur when there is direct contact with steel can be avoided. If the ceramic layer is made of calcium phosphate, it will be meaningless as it will replace the bone, and if Be + Ba + P b r As
Of course, it must not contain substances harmful to the human body, and A12011 and the like are preferable because they are not harmful to the human body.

FIG. 3 is a longitudinal cross-sectional view of the artificial joint, and numeral 17 indicates a noble metal plating or ceramic coating layer.

As described above, the artificial joint according to the present invention has no adverse effects on the living body,
The sliding parts have high wear resistance, which brings great news to injured people.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional artificial joint, and FIG. 2 is a longitudinal sectional view of the artificial joint of the present invention. / , //... socket, co... bone cement,
3.13... femoral head ball member, μ, l≠... stem,!
...Bone cement, lco, /4...Calcium phosphate coating layer, /7...Precious metal or ceramic coating layer procedure amendment (method) Showa! 7th year io month 7th Patent Office Commissioner Cha, 1), Japanese dog lord case display Showa! 7 Year Patent Application No. 1/3734 2 Name of the invention Artificial joint 3. Relationship with the person making the amendment Case Patent applicant postal code 17-ta 1 Takatsuji-cho, Mizuho-ku, Nagoya City! ψ number/j number: A column for a brief explanation of the drawings in the specification subject to amendment. 6. Details of the amendment As shown in the attached sheet, the brief explanation column of the drawing in line 1'I from the top of page 10 of the specification will be corrected as follows. " Figure 1 is a longitudinal sectional view of a conventional artificial joint, and Figure 2 is a longitudinal sectional view of an artificial joint of the present invention. Figure 3 is a longitudinal sectional view of an artificial joint showing another example of the present invention. /, / /...Socket, Co...Bone cement, 3
．． /3...Female head ball member, V, /eye/stem,!・・・
・Pawn'cement, /2. /'4...Calcium phosphate coating layer, /7...Precious metal or ceramic coating layer"

Claims (1)

[Scope of Claims] (1) A socket having an exposed spherical inner surface of sialumina porcelain made of alumina porcelain having an outer surface coated with calcium phosphate, a dense nitrided socket that rotatably slides on the spherical inner surface of the socket. 1. An artificial joint comprising a femoral ball member made of silicon porcelain, and a stem made of a metal base having a coating layer of calcium phosphate on the outer surface and connected to the femoral ball member. -) The artificial joint according to claim 1, wherein the femoral head ball member and the stem are joined by a V-shaped joint. (3) The outer surface of the socket and/or the outer surface of the stem is a porous surface having a large number of pores of θμ to jOOμ! The artificial joint according to item 1 or 2 of the scope of Fg Aokyu. (An artificial joint according to any one of claims 1 to 7, in which the base metal of the stem is defective steel.) Claim 1, in which the base metal of the stem is defective steel plated with a precious metal. 1-Artificial joint according to item D. (J) The artificial joint according to Claims 1 to 4, wherein the base metal of the stem is a defective steel coated with a ceramic coating layer excluding calcium phosphate.