JPH04166148A - Bioprosthetic member - Google Patents

Abstract

PURPOSE:To obtain the equal effect in supporting and fasting properties of a bioprosthetic material while eliminating complication of a production process by forming a surface structure with a fine space having an angle theta in a specified range at a surface section contacting a bone tissue in an artificial joint or a bone prosthetic member with a normal of the surface section as reference. CONSTITUTION:An artificial knee joint shank member 1 as bioprosthetic member is set on a shank T and a fine hole H is set on a surface 1a contacting an excised surface Ta of the shank T. The fine hole His at an angle theta ranging from 0 deg. to 60 deg. to a vertical line (x) of the surface 1a contacting a shank surface Ta and some thereof have an opposite inclination individually. Thus, a large resistance force is shown to a load F even when it works on a shank bone member 1. For example, the fine holes H are cut into the surface 1a of the shank member 1 respectively with a diameter of 0.3mm and 0.5mm and a death of 0.4mm and 0.6mm to make a fine space upon which the bone grows to encroach. The theta is set at 10 deg. clockwise and 10 deg. counterclockwise alternately.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a surface structure of a prosthetic member for prosthetizing a bone defect in a living body or an artificial joint for replacing a deformed joint of a living body. It is mainly used for artificial bones, artificial joints, and artificial tooth roots used in the treatment of diseases such as bone and soft tissue tumors, rheumatoid joints, osteoarthritis, and bone fractures.

[Conventional technology]

Artificial prosthetic materials are sometimes used to replace part or all of bones in upper and lower limbs that have to be removed due to bone and soft tissue tumors.

In addition, deformity may occur due to severe injuries caused by a traffic accident, fractures that occur in areas that are difficult to heal, or diseases such as rheumatoid arthritis, osteoarthritis, or bone head necrosis. Various types of artificial joints are used to replace joints in the human body that are no longer functional.

Similarly, in the case of teeth, artificial tooth roots are used as substitutes after tooth extraction, and the demand for these artificial bones, artificial joints, and artificial tooth roots will continue to increase in the future.

There are various types of surface structures for artificial bones, artificial joints, and artificial tooth roots that have been used so far. In order to maintain good adhesion of prosthetic materials to living bone tissue, which has a major impact on the postoperative results of artificial bones and joint replacement surgery, various techniques related to the surface structure of prosthetic materials have been researched and are being applied to actual products. It is applied. Typical examples are metal spherical particles (approximately 200μ to 500μ particle size) fixed to the surface of a metal material by sintering, and metals (mainly titanium materials).
There is a type of reticular material that is subjected to pressure and high temperature treatment. When pores on the order of 100 microns formed on the surface of the prosthetic component by these methods come into contact with bone tissue, under favorable stress conditions, the bone tissue may invade the pores, or the prosthesis may be damaged. It has a great effect on improving supporting capacity.

In addition, as a method different from this, JP-A-1-265955
As shown in Figure 2, some methods have been devised to regularly arrange pores with a shape suitable for bone tissue penetration.

These two typical examples relate to the surface structure, and the present invention is also similar to these, or as a means of increasing the so-called affinity with bone tissue, it is possible to add substances with osteoconductive or osteoinductive properties to the surface of the material. There are many products that undergo treatments such as coating.

[Invention or problem to be solved]

The method of sintering metal particles on a metal substrate in order to improve the surface structure involves a high-temperature process called sintering, which leads to deterioration of the strength of the metal substrate, especially a decrease in fatigue strength. It goes down to 10-6096. In addition, metal particles may fall off the surface during insertion of the prosthetic component,
It has also been pointed out that it invades the sliding surfaces of joints and causes friction in artificial materials.

In addition, in the method of using a metal mesh, there is still room for improvement as the method of sintering the metal particles does not deteriorate the strength of the metal base, and the distribution of pores in the mesh does not necessarily become uniform.

The invention of JP-A-1-265955 requires a process of incorporating a member with pores into a prosthetic material, and this process may result in areas that cannot be applied, and depending on the method of incorporation, metal corrosion or strength deterioration may occur. can cause

In any of the above methods, a step such as a sintering step of metal particles is added to the normal steps for manufacturing a prosthetic member, which naturally leads to an increase in manufacturing costs. Also, from the aspect of quality assurance, more advanced technology is required.

The present invention aims to eliminate the complication of the manufacturing process that occurs with the improvement in the adhesion of artificial materials as described above, and to provide the same effect on the support and adhesion of bioprosthetic materials. be.

[Means to solve the problem]

In order to solve the above problems, in the present invention, a large number of microholes or microgrooves are formed on the surface of the prosthetic member at an angle θ in the range of 0° to 60' with respect to the normal direction of the surface. Provides a microscopic space with directionality.

It is preferable that the microholes be made with a drill or the like that is commonly used for processing metals. The diameter of the micropore is 0.2~
It is preferably about 0.5 mm, and the depth may be about the same as the hole diameter or several times that.

[Effect]

As mentioned above, in a bioprosthetic material with many directional micropores or microgrooves formed on its surface, bone tissue proliferation occurs near the micropores or microgrooves due to the action of osteoblasts on the surface. However, healthy bone tissue can penetrate into the micropores or microgrooves. As a result, the bone tissue naturally has many directions, similar to the micropores or microgrooves, and the peel strength between the bone tissue and the prosthesis increases theoretically dramatically in various directions. Whether the surface of the bioprosthetic component is subjected to a combination of compressive stress, tensile stress, and shear stress in the living body, and whether the surface of the bioprosthetic component is sufficiently effective to maintain the adhesion of the prosthetic component even under such conditions. I can do it.

〔Example〕

Examples will be described with reference to the drawings.

FIG. 1(a) shows a state in which an artificial knee joint tibial member 1, which is a bioprosthetic member, is installed on the tibia T. 1st
Figure (b) shows a view of the artificial knee joint tibial component J in which a small hole H is installed in the surface 1a that is in contact with the resection surface Ta of the tibia T. FIG. 1(C) shows an enlarged view of a part of the surface 1a and its cross section, and the microhole H of the present invention forms an angle θ with respect to the perpendicular X of the surface 1a in contact with the tibial surface Ta. Some have slopes in opposite directions. As a result, even if a load F as shown in FIG. 1(a) is applied to the tibial component 1, it can exhibit a large resistance force against it.

The surface 1a of the tibial component 1 that was actually prototyped had a diameter of 0.3 mm.
mm (300μ) and diameter 0.5 mm (500μ)
The hole depth is 0.4 mm and 0.6 mm, respectively.
The bone is perforated, forming a microspace into which bone can grow.

θ was lOo, and 10″ clockwise and IOo counterclockwise were installed alternately.

The arrangement of the micropores H can be a simple lattice-like arrangement in the prototype, one that takes close-packing into consideration, or a center-to-center distance calculated after setting the occupancy rate of the micropores H in advance. . The dimensions of the prototype grid were 0.6 mm for those with a diameter of 0.3 mm, and 1.0 mm for those with a diameter of 0.5 mm.

In addition, it is not necessary to arrange only microholes H with the same diameter on the same tibial resection surface, but with microholes H with different diameters.
In some cases, it may be desirable to simultaneously place both on the same tibial resection surface or on the contact surface with bone tissue.

Furthermore, the material for making the microhole H, that is, the material for the prosthetic member, can be any material currently used as a so-called biomaterial without any problem.

Examples include metal materials such as titanium alloys and cobalt chromium alloys, ceramic materials such as alumina, zirconia, and apatite, and organic materials such as ultra-high molecular weight polyethylene. It also includes composite materials and coating materials.

As an embodiment of the present invention, titanium alloy (Ti-
6A! -4V) was used. In addition, the following experiment was conducted to confirm the effect of micropores.

Plate-shaped (IOX 15X 2 mm) titanium alloy (Ti
-6Al -4V) was prepared, and a 1010x15 plane (
Microholes were drilled on 2 sides).

That is, test piece A has a micropore diameter of 0.3 mm.
, hole depth 0.4 mm, interlattice distance 0.6 mm, test piece B has micro hole diameter 0.5 mm, hole depth 0.6 mm.
, micro holes with an interstitial distance of 1.0 mm were drilled on both sides. The angle of the micropores is 10°.

Three of each of the above test pieces A and B were inserted into the proximal tibia of an adult rabbit, and removed together with the bone 8 weeks after the operation. Next, in order to evaluate the adhesion of the test piece to the bone, a peel test was performed on the extracted bone and the test piece composite.

The measurement result is 2.53Kg±0.71 for test piece A.
Kg, test piece B is 3.28Kg±0.65K
It was g.

On the other hand, the peeling force of control test piece C without micropores H was 0.53.
Kg±0.29Kg, and based on this, test piece A is 4.8 times the average value, and test piece B is 6.
It doubled, confirming the effect of micropores H.

FIG. 2 shows a case where the groove is a long and narrow microgroove M. The surfaces of artificial joints and prosthetic components are sometimes composed of curved surfaces rather than flat surfaces, and in order to accommodate such complex surfaces, it is necessary to have not only micro holes H but also micro grooves M. It is.

Further, the microgroove M has an elongated shape compared to the micropore H, and the amount of invading bone tissue increases, leading to an improvement in the bonding strength with the bone tissue.

FIG. 2 is an enlarged view of the surface 1a in FIG. A plurality of micro grooves M having inclinations in opposite directions are formed.

Furthermore, FIGS. 3(a) and 3(c7) show an example in which the surface structure according to the present invention is applied to a metal femoral side member S as an artificial prosthetic member used in a total hip joint prosthesis. Micropore H
The area in which this is provided is a difficult area for mechanical locking, and providing the microhole H of the present invention in such an area improves the supporting force between the femur and the metal femoral side member S.

Similarly, in FIG. 4, a proximal femoral prosthetic material P is selected from among the bioprosthetic materials, and the microhole H is inserted into the medullary canal insertion member P.

An example of application to a prosthetic part near bone resection P2 is shown.

Furthermore, FIG. 5 shows an example in which the bioprosthetic member having micropores H according to the present invention was applied to an artificial tooth root, and a product with high bonding strength to the jawbone was obtained.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects.

By forming the micropores of the present invention in the parts of bioprosthetic materials, artificial joints, and artificial tooth roots that contact bone tissue or are implanted, or in the vicinity thereof, healthy bone tissue grows into the micropores and connects with the bone. It becomes possible to increase the fixing force at the interface with the prosthesis and prevent even minute movements from occurring. In particular, it is possible to increase the strength against forces that would tear apart a flat surface, that is, tensile force and shear force.

Further, in the process of manufacturing the prosthetic member, no extra heat treatment is required, so there is no problem with deterioration in the strength of the material, especially deterioration in fatigue strength. Therefore, the present invention can be applied even to relatively thin round bar-shaped prosthetic members that are at risk of fatigue failure.

In addition, the size and shape of the drilled micropores or microgrooves are uniform, and the pore diameter, that is, the pore diameter, is extremely easy to control.
Pores of about 400 microns can be made regularly on any surface, and the prosthetic member can be surrounded by bone tissue to prevent loosening between the two for a long period of time.

[Brief explanation of drawings]

FIG. 1(A) is a front view showing a state in which an artificial knee joint tibial component as a bioprosthetic component according to the present invention is attached to the proximal end of the tibia, and FIGS. 1(B) and (C) are respectively Part l
FIG. 2 is a partially enlarged sectional view of an embodiment in which micropores H are formed and a surface on which micropores H are formed. FIG. 2 is a perspective three-dimensional enlarged view showing another embodiment of a portion corresponding to FIG. 1(C). 3, 4, and 5 are side views showing examples in which the bioprosthetic member according to the embodiment of the present invention is applied to a stem of an artificial hip joint, a prosthetic material for a proximal femur, and an artificial tooth root, respectively.

Claims (1)

[Claims] A bioprosthetic member characterized by a surface structure having a microspace having an angle θ in the range of 0° to 60° with respect to the normal direction of the surface on the surface in contact with bone tissue in an artificial joint or a bone prosthetic member. .