JPS6040858B2 - Highly tough orthopedic implant components with excellent corrosion and wear resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to orthopedic implant members such as bone screws and Kojinai nails that have excellent corrosion resistance, wear resistance, and toughness.

Currently, metal materials such as stainless steel and inorganic materials such as single crystal alumina are generally used in the manufacture of orthopedic implant components as described above.

However, since the above-mentioned metal materials do not have sufficient corrosion resistance, it is common for corrosion to progress to the extent that the original shape cannot be retained within the body even one year after surgery, and in some cases, new It may be necessary to replace it with a new one, or even remove it without replacing it. On the other hand, the latter type of inorganic material has excellent biocompatibility, corrosion resistance, and abrasion resistance, but has extremely poor quality, making it difficult to handle and expensive. be. Therefore, from the above-mentioned viewpoints, the present inventors conducted research to obtain an orthopedic implant member that has excellent biocompatibility, corrosion resistance, and abrasion resistance, and also has excellent graininess at a low cost. As a result, the main body is made of high-alloy steel such as stainless steel, Ni-based alloy such as Hastelloy, or Co-based material such as Stellite.
In addition to being composed of a base alloy, the surface of the main body is coated with Ti nitrides, carbides, carbonitrides, carbonates, and carbonitrides using ordinary chemical vapor methods, ion plating methods, plasma chemical vapor deposition methods, etc. aluminum oxide, oxynitride, and aluminum oxide (hereinafter referred to as TIN, TIC, and TI, respectively)
CN, TIC○, TICN○, TIN○, and AI2
A monolayer or two of the following (indicated by the chemical symbol C3)
In orthopedic implants that are coated with a hard surface layer consisting of a grain layer or more with an average layer thickness of 0.5 to 50 mounds, the main body ensures excellent rutting resistance, and the hard surface layer This ensures excellent biocompatibility, corrosion resistance, and abrasion resistance, and the material cost of the main body and the formation cost of the surface hard layer are relatively low.
Therefore, they found that it is cheaper than the secondary one made of inorganic material. This invention was made based on the above knowledge, but the reason why the average layer thickness of the surface hard layer was limited to 0.5 to 50 mm was that the average layer thickness was 0.5 mm to 50 mm.
5 Buddha's Compassion: ``The desired excellent biocompatibility, corrosion resistance,
This is because it is not possible to ensure abrasion resistance, and on the other hand, if the thickness exceeds 50 mm, cracks not only tend to occur, but also cause high costs.

Next, the orthopedic implant member of the present invention will be specifically explained using examples.

Examples Austenitic stainless steel as high alloy steel, Co
Bone screws and bone supports as orthopedic implant component bodies are manufactured using Stellite as the base alloy and Hastelloy as the Nj-based alloy, and then the surfaces of these component bodies are coated with a conventional chemical vapor deposition method. Implant members 1 to 34 of the present invention were also manufactured by forming hard surface layers having the materials and layer thicknesses shown in Table 1 using the Tinku method and the plasma chemical processing method, respectively.

Next, the resulting implant member angle of the present invention ~
Among 34, implant members of the present invention 1, 3, 5?14,
16, turtle 8, 20?23, 26, 38, and 32,
For comparison purposes, the comparative implants No. 1 to No. 3 of Table 1, which do not have the formation of the above-mentioned hard surface layer, were surgically implanted in 12-month-old rabbits, and after 6 months, the orthopedic portion was removed. A biological corrosion test was conducted by cutting it open and observing the corrosion state.

As a result, all of the implant members of the present invention exhibited excellent corrosion resistance, remained in their original shape, and showed no corrosion at all, whereas comparative implant members 1 to 3, which did not have a hard surface layer, As for the bone screw, the cruciate part of the head was so corroded that it no longer retained its original shape, and the bone support odor was so corroded that the edge part receded by about two legs. Further, regarding the above-mentioned implant members 1 to 34 of the present invention and comparative implant members 1 to 3, conditions under which in vivo corrosion can be estimated, namely, water:
Aqueous hydrochloric acid solution with 100% hydrochloric acid added to 100%,
A hydrochloric acid aqueous solution immersion test and a saline solution immersion test were conducted using 200' of 23% saline solution and immersion in both solutions at a temperature of 23oC for 5 hours, and after the test, the Weight loss was measured.

The measurement results are shown in Table 1 along with the Vickers hardness. From the results shown in Table 1, implant members 1 to 34 of the present invention exhibit much better corrosion resistance than comparative implant members 1 to 3, and have extremely high hardness, so they also have excellent wear resistance. It is clear that As mentioned above, the orthopedic implant member of the present invention has excellent magnetism due to its main body, so there is no need to take great care when handling it, and the hard surface layer provides excellent biocompatibility and Since corrosion resistance and abrasion resistance are ensured, it exhibits excellent performance over a long period of time in practical use, and has industrially useful properties such as being inexpensive to manufacture.

Claims (1)

[Claims] 1. On the surface of the main body made of high alloy steel, Co-based alloy, or Ni-based alloy, one of Ti nitride, carbide, carbonitride, carbonate, carbonitride, and oxynitride, and aluminum oxide. A high-toughness orthopedic implant member having excellent corrosion resistance and abrasion resistance, which is coated with a surface hard layer consisting of a single layer or a multilayer of two or more types with an average layer thickness of 0.5 to 50 μm.