JPH01249049A - artificial knee joint - Google Patents

Abstract

PURPOSE:To obtain an excellent hemi-artificial knee joint by coating a metal made base structure of large mechanical strength respectively in its side, coming into contact with a bone, with a vital activator material layer and the sliding side with a wear resisting material layer. CONSTITUTION:A base structure 11 of a joint member 1 is made by metal of Co-Cr alloy, titanium alloy, etc., forming a curved shape easily suited for a thighbone Db in its bone end part shape, and this base structure 11 coats its surface in a side, adapted to the thighbone Db, with a vital activator material layer 11a and the surface in a side, sliding as a joint, with a wear resistance material layer 11b. As a material forming the vital activator material layer 11a coating for firmly connecting the joint member 1 to the bone, hydroxyapatite, vital activator glass and beta-TCP(tricalciumphosphate) or these combination may be used. While for the wear resistance material layer 11a coating the surface in the side sliding with a joint member 2 mounted to the shinbone, titanium nitride, titanium carbide, titanium carbide nitride, alumina, etc., are applied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an orthopedic artificial knee joint for restoring joint function lost due to disease, disaster, etc. in the human body.

[Conventional technology]

When joint function of limbs is impaired due to bone diseases such as osteoarthritis or rheumatoid arthritis, artificial joint replacement surgery is often performed as one of the open treatments in orthopedics. In particular, there are many cases in the knee joint, which is a load-bearing joint.
The number of cases exceeds 20,000 annually.

There are two types of artificial knee joints: the surface replacement type, which repairs only the sliding surface of the knee joint, and the hinge type, which replaces the entire knee joint, but the surface replacement type is mainly used.

This surface replacement type artificial knee joint consists of a femoral side member K and a tibial side member K made of metal or ceramic, as illustrated in Figs. 4, 5, and 6, respectively. The most commonly used moving parts are those in which ultra-high molecular weight polyethylene parts are fitted.

In addition, most femoral components of surface replacement type knee joints replace the entire buccal surface of the distal end of the femur, but there are also types that replace only one of the lateral or medial condyles, as shown in Figure 5. ,
It is called a hemi artificial knee joint. In any of these artificial knee joints, it was necessary to integrally provide a fixing pin P to be inserted into the jawbone in order to increase the strength of fixation with the femur.

In general, surface replacement type artificial knee joints emphasize minimizing the amount of bone cut as much as possible, and when only one side of the jawbone is affected, a hemi-artificial knee joint is preferred.

The hemi-artificial knee joint has a greater advantage in that it requires less bone cutting because it has a thinner wall thickness than a general artificial knee joint.

[Problem that the invention seeks to solve]

Of these, the hemi artificial knee joint shown in Figure 5 has traditionally been made of cobalt-chromium alloy, stainless steel, etc.
Although it has the above-mentioned advantages, it sometimes causes elution of metal ions and even turns the affected area black.

In addition, as a bioprosthetic member, its fixability to the living body is not very good, and many of them tend to become loose due to the appearance of a clear zone at the bonding interface with the bone over time.

On the other hand, an alumina ceramic hemi-artificial knee joint as shown in Figure 6 is also used, and its wear resistance has been greatly improved.
Although there was no elution of metal ions and the biocompatibility was good, the fixation was not sufficiently improved because the alumina material was bioinactive.

Moreover, since alumina ceramic is a highly rigid material (brittle material), the wall thickness had to be increased, and as a result, one of the features of the Hemi artificial knee joint was lost.

Therefore, the problems to be solved by the present invention can be summarized as follows.

3. Problem with the amount of bone cut □Increase in the amount of bone cut 4. Problem with wear resistance □ Decrease in durability [Means for solving the problem] The present invention aims to solve the above five problems at the same time. The base of the joint member is made of a metal with high strength, and the side that contacts the bone is coated with a bioactive material such as hydroxyapatite to increase fixation with the bone, and the other side of the joint member is made of a metal with high strength. The joint member was constructed by coating the moving surface with a wear-resistant material such as titanium chloride or alumina, which has excellent wear resistance.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows a perspective view of a hemi-artificial knee joint, which is composed of a joint member 1 attached to the distal end of the femur and a joint member 2 attached to the tibia, as shown in FIG. They are attached to the femur and tibia, respectively.

Among these, the base body 11 of the joint member 1 is made of metal such as Co-Cr alloy or titanium alloy, and has a curved shape that easily adapts to the shape of the disposed end of the femur Db. A bioactive material layer 11a is coated on the surface that comes into contact with the joint, and a wear-resistant material J is coated on the surface that slides as a joint.
i! fllb is attached.

By the way, the materials forming the bioactive material layer 11a to which the above-mentioned joint member 1 is adhered in order to firmly connect with the bone include hydroxyapatite, bioactive glass, and β-TC.
It may also be a combination of these. In addition, effective methods for applying such a bioactive material to the surface of the base 11 of the joint member 1 include thermal spraying, sputtering, ion blasting, and precipitation.For bioactive glass, melt coating is effective. It can also be done by law.

Furthermore, a bioactive material layer 11a applied by the above-mentioned means
The preferred thickness is 5 to 100 μm, and when the thickness is 5 μm or less, no significant improvement was observed in the osteoconductivity and stability of the augmented bone. Moreover, if the thickness is 100 μm or more, not only will the cost be high, but the inside of the bioactive material layer 11a will be easily destroyed, that is, the bonding strength with the bone will be low.

On the other hand, titanium chloride, titanium carbide, titanium carbide, alumina, etc. are used as the wear-resistant material layer 11a attached to the surface that slides on the joint member 2 attached to the tibia. In addition to the ion blasting method, sputtering method, thermal spraying method, etc., ion implantation method using nitrogen ions or the like can also be used as a deposition method. Furthermore, when the thickness of the wear-resistant material layer 11b was 50 μm or less, sufficient wear resistance was exhibited, and even when the thickness was, for example, 5 μm or less, it could withstand use for a sufficiently long period of time. However, a thickness of 50 μm or more tends to cause interlayer failure, which is not preferable.

Furthermore, a first
As shown in figure (b), a large number of unevenness 11c is formed,
By covering these upper surfaces with the bioactive material layer 11a, it is possible to achieve stronger bonding with the bone.

The unevenness 11C may be a groove formed by knurling or a large number of wart-like protrusions.

In the above embodiment, a hemi-artificial knee joint has been described, but the gist of the present invention is of course applicable to other types of artificial knee joints.

[Effect of the invention] Like soft soil, according to the present invention, a bioactive material layer is provided on the side of the metal base with high mechanical strength that comes into contact with bones, and a wear-resistant lumber layer is provided on the sliding side. Since the fixation strength within the bone is greatly improved by attaching each of The amount of bone cut is minimal. In addition, the surgical procedure is also more convenient because the shaping of the bone end to which it is attached is easier.

In addition, since the outer surface of the metal base is covered with a bioactive material layer and a wear-resistant material layer, it is possible to improve the corrosion resistance of joint members and to prevent ion elution. A knee prosthesis can be produced, especially a hemi-prosthesis.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an artificial knee joint according to an embodiment of the present invention, and FIG.
Figure (a) is a cross-sectional view taken along line X-X in Figure 1, and figure (b)
1 is a cross-sectional view of another embodiment corresponding to the line X-X in FIG. 1, FIG. 3 is a perspective view showing the state in which the artificial knee joint according to the present invention is installed between the femur and tibia, and FIG. 4 , FIG. 5, and FIG. 6 are both perspective views showing examples of conventional artificial knee joints. 1.2: Joint member 11a: Bioactive material layer 11b: Wear-resistant material layer

Claims (1)

[Claims] A joint member to be attached to the epiphysis of the femur, the member comprising a curved base made of a metal material, and a bioactive material layer on the side of the base that comes into contact with the epiphysis, An artificial knee joint characterized in that a layer of wear-resistant material is applied to each side of the joint that slides.