JPH078513A - Artificial joint - Google Patents

Abstract

PURPOSE:To keep the fixation of an artificial joint and a bone from being lost with the lapse of time by forming a covering adhesive part for covering a gap between an artificial joint part and a living body bone. CONSTITUTION:An artificial joint (shelf) 11 comprises a fixing part 12, a sliding part 13 and a covering adhesive part 14. The shelf fixing part 12 is formed by Ti, Ti alloy, SUS 316, Co-Cr alloy, or the like and can be fixed to the shelf bone or bone cement. The sliding part 13 is formed from an ultra-high-molecular weight polyethylene and made closely adhere to the shelf fixing part 12. The covering adhesive part 14 is joined to the edge of the shelf fixing part 12 or the edge of the sliding part 13 to be connected to the periphery of the edge. The covering adhesive part is, preferably formed from a soft material because it is easily made closely adhere to the living body bone, but a hard material can be also used if it is previously formed in such a manner as to be matched with the form of the living body bone. Thus, abrasion powder such as polyethylene or the like can be kept from entering between the bone and the artificial joint or between the bone and cement so as to prevent loosening.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial joint which replaces a bone joint of a living body.

[0002]

2. Description of the Related Art Artificial joints are often used in orthopedics to restore the joint function by prosthesing the joints of the human body when the joints are deformed, defective, necrotic or the like. The artificial joint includes an artificial hip joint, an artificial knee joint, an artificial shoulder joint, an artificial elbow joint, an artificial ankle joint, an artificial finger joint, and the like, depending on the site of use.
Especially, the amount of artificial hip joints and artificial knee joints used is much larger than other joints. The artificial hip joint is further composed of a femoral component that is fixed to the femur and functions as a femoral head, and an acetabular component that is fixed to the hipbone and functions as an acetabulum. In many cases, the femoral component is inserted through the cut end of the femoral neck and is supported and fixed by the femoral shaft. The part that is inserted into the diaphyseal portion of the artificial hip joint and is supported and fixed is usually called the stem. It is called the neck between the stem and the head of the bone.

Material is usually stainless steel SUS316L, C
It is made of an o-Cr alloy, a Ti alloy, or the like. Most of the acetabular parts are composed of a sliding part that is combined with the head of the bone to perform joint movement, and an acetabular fixing part that wraps the sliding part to hold the shape and fix it to the bone. Ultra-high molecular weight polyethylene is used for the sliding portion, and the acetabular fixing portion is made of polyethylene itself of the sliding portion or a cup of the metal material. Many of the above-mentioned artificial joints are fixed to bone by bone cement (such as those containing polymethylmethacrylate, which is a synthetic polymer as a main component), or fitting force of fitting.

[0004]

However, such an artificial joint has many problems. One of them is that the fixation between the artificial joint and the bone is lost over time (loosening), and the joint function is broken. The causes of this loosening are wear debris produced as a result of the wear of the bone head and slip parts by joint movement, especially polyethylene wear powder of the slip part that wears more than the bone head, and bone cement used for fixation. It is said that phagocytic cells, which are in charge of processing foreign substances, act on the degradation products of erythrocytes to cause an inflammatory reaction, resulting in the dissolution of bone. Polyethylene wear powder produced by joint motion is taken up by the soft tissue around the joint and further migrates to enter between the bone and the artificial joint or between the bone and bone cement, and dissolves the bone tissue in the vicinity due to the inflammatory reaction. It ends up.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies in view of the above problems, and as a result, have found that the following invention can solve the problems. (1) An artificial joint that replaces a joint part of a bone of a living body, the artificial joint having an artificial joint part and a coating adhesive part for covering a gap between the artificial joint part and the living bone. (2) The above-mentioned (1) in which the coated adhesive portion is made of a soft material.
The described artificial joint. (3) 50 to 200 on the surface of the soft material near the living bone
The above (1) having a large porous layer consisting of 0 micron voids
And the artificial joint according to (2).

(4) The soft material is 0.0 on the joint cavity side.
The artificial joint according to (1) or (2) above, which is a microporous layer having micropores of 1 to 5 microns. (5) The soft material is made of a biocompatible synthetic polymer and is in the form of at least one of gel, film, knit, woven fabric, porous body and nonwoven fabric.
(4) The artificial joint according to the above. (6) The artificial joint according to (1) to (5) above, wherein the soft material partially contains a biomedical metal material.

The sliding part of an artificial joint usually has a molecular weight of 300.
Polyethylene (ultra high molecular weight polyethylene, UHMWPE, PE) of about 10,000 Dalton is used. PE is a material that has much less wear than Teflon and is less problematic. However, after artificial hip joint replacement surgery, due to inflammation due to PE abrasion powder, the space between the bones loosens around 10 years, and it becomes impossible to perform a sufficient function. In the artificial joint of the present invention, by providing the covering adhesive part for covering the gap between the artificial joint part and the living bone, PE abrasion powder generated by sliding between the bone head part and the sliding part is fixed to the acetabular fixing part. Loosening is prevented by preventing entry into the femoral bone marrow between the acetabular bones or around the stem.

A specific description will be given with reference to the drawings. The application in the artificial hip joint will be described here. FIG. 1 is a sectional view of an acetabular artificial joint of the present invention. The artificial joint (acetabular lid) 11 is composed of an acetabular fixation portion 12, a slip portion 13, and a coating adhesive portion 14. The acetabular fixation part 12 is usually made of Ti, Ti alloy, SUS316L, Co-Cr alloy, or the like, and is devised so that it can be firmly fixed to the acetabular bone or bone cement. As described above, the sliding portion 13 is usually made of ultra-high molecular weight polyethylene and is in close contact with the acetabular fixing portion 12.

The covering adhesive portion 14 is joined to the edge of the acetabular fixing portion 12 or the edge of the sliding portion 13 and is continuously provided around the edge. In the present invention, as a method for joining, a concave portion is provided on the surface of the artificial joint and the covering adhesive portion is sandwiched therein, or a small hole is provided around the covering adhesive portion joining portion of the artificial joint, and fibers such as polyester and titanium are formed. There is a method of sewn the covering adhesive portion using the method. Cover adhesion part 14
Is preferably a soft material because it can be easily attached to a living bone, but a hard material can also be used by previously molding it so as to match the shape of the living bone. As a material, in the case of a soft material, a silicone rubber or a polytetrafluoroethylene (PTFE) -based film that is not harmful to living organisms is preferable, and the following constitution can be adopted to obtain a more reliable effect. .

(A) The surface 15 of the coated adhesive portion 14 near the living bone is a large porous layer having voids of 50 to 2000 microns. This facilitates the invasion of granulation tissue from the periosteum and soft tissue around the acetabulum and improves the shielding property. As the macroporous layer, a processed product of a soft material such as polyester fiber woven fabric, knitted fabric, non-woven fabric, and polyurethane sponge that is less toxic to the living body can be used.

(B) The joint cavity side 16 of the coated adhesive portion 14 is a fine porous layer having fine voids of 0.01 to 0.5 micron. While blocking PE abrasion powder, water, electrolyte,
Since it penetrates some proteins and the like, it does not deteriorate the environment of the periosteum and the soft tissue covered by the coated adhesive part. As a material for this portion, a porous film such as polyurethane, polypropylene, or PTFE is suitable.

(C) By partially containing the biomedical metal material 17 in the coated adhesive portion 14, it becomes easy to align the coated adhesive portion with the unevenness of the tissue around the acetabular fixation portion 12. Biological metal materials include Ti, Ti alloys, SUS31
What is normally used as an implant material such as 6L and a Co—Cr alloy may be used.

The method of attaching the artificial joint (acetabular cover) 11 is as follows. The acetabular bone of the patient is artificial joint (acetabular) 11
Before the bone cement is hardened by cutting it according to the outer surface shape of the acetabular fixation part 12, and applying a bone cement made of collagen-hydroxyapatite or the like to the cutting part and paying attention to the attachment angle of the artificial joint (acetabular) 11. Press to secure the acetabulum. After that, the coated adhesive portion 14 is pressed so as to match the shape of the surrounding tissue.

FIG. 2 is a sectional view of the artificial joint (femur) of the present invention. The artificial joint (femur) 21 includes a bone head 22, a neck portion 23, a stem portion 28, and a coating adhesive portion 24. The bone head 22 is made of Co—Cr alloy, zirconia ceramics, or the like. The neck portion 23 and the stem portion 28 are usually integrally formed, and Ti, Ti alloy, SUS316L, Co—Cr alloy and the like are suitable. The covering adhesive portion 24 projects from the vicinity of the boundary between the neck portion 23 and the stem portion 28 in the direction perpendicular to the stem portion 28. The material is the same as the covering adhesive portion 14 of the artificial joint (acetabulum).

The method of attaching the artificial joint (femur) 21 is as follows. After cutting the femoral neck, the bone marrow cavity is reamed according to the shape of the stem portion 28. After filling the bone marrow cavity with bone cement, the femoral component stem portion 28 is inserted and fixed in the bone marrow cavity before hardening of the bone cement. After that, the coated adhesive portion 24 is pressed so as to match the shape of the surrounding tissue. The application of the artificial joint of the present invention in the artificial hip joint has been described above.
It is needless to say that it can be similarly used for artificial knee joints, artificial shoulder joints, artificial elbow joints, artificial ankle joints, artificial finger joints, and other parts to prevent the invasion of wear particles. Hereinafter, the present invention will be described in more detail with reference to examples.

[0016]

【Example】

Example 1 In order to confirm the effect of the coated adhesive part used in the artificial joint of the present invention using a rabbit hip joint, the following experiment was conducted. Preparation of PE abrasion powder A plate material made of ultra-high molecular weight polyethylene (Newlite, manufactured by Sakushin Kogyo Co., Ltd.) and zirconia ceramic (produced by Shinagawa Shiro Brick Co., Ltd.) were rubbed together in physiological saline to prepare abrasion powder. Preparation of Soft Material Covered Adhesive Part Ti fiber was woven into polyester fiber and polypropylene porous body was further bonded by point fusion to prepare a coated adhesive member. The polyester woven fabric had a pore size of 100 to 500 μm and a thickness of 0.7 mm, and the polypropylene porous body was a porous membrane having an average pore size of 0.5 μm and a thickness of 150 μm, which was prepared by the extraction method.

Implantation in Rabbit A white Japanese rabbit (weight 2.5-3.0 kg, male) is exposed at the femoral head and the neck of the femur is cut. As an experimental group, the cut surface of the femur was covered with the above adhesive covering member of the soft material, PE abrasion powder was added to the wound, and the wound was directly reduced and the peripheral muscle and skin were sutured. After 12 weeks, the animals were sacrificed and pathological observation was performed on the proximal part of the femur. Similar treatment was performed without using the soft material skirt as a comparison group. Results In the femoral bone marrow cavity of the experimental group, fibrous tissue was found near the coated adhesive member, but the bone marrow tissue was generally healthy. In the femoral bone marrow cavity of the comparative group, fibrous tissue invaded from the cut end, and the bone marrow was reduced. Foreign matter, which appeared to be PE wear powder, was scattered in the fibrous tissue, and many foreign matter giant cells were found around it.

(Example 2) A acetabular fixing part made of Ti and a slip part made of ultra-high molecular weight polyethylene (Nulite, manufactured by Sakushin Kogyo Co., Ltd.) are provided around the circumference of the acetabular fixing part of the artificial acetabulum. A groove was continuously provided on the top. In the vicinity of the center of the coated adhesive member created in Example 1-, a hole having the same diameter as the circumference of the concave groove of the mortar lid fixing portion is opened, the artificial mortar of the hole is inserted, and the coated adhesive member is inserted into the concave groove. An artificial acetabular lid for a dog was prepared by sandwiching and fixing. Similarly, a bone head made of Co-Cr alloy,
The coated adhesive member produced in Example 1 was joined to the neck portion of the artificial femur having a Ti neck and stem to produce a dog artificial femur.

The artificial acetabulum and artificial femur were transplanted into a hybrid dog, and the polyethylene abrasion powder used in Example 1 was added to the periphery of the artificial acetabulum and artificial femur before closing the wound. As a comparison, the same treatment was performed using the same artificial acetabulum and artificial femur as described above except that the coated adhesive member was not joined. Twelve weeks later, the animals were sacrificed, and pathological observations were performed on the artificial acetabulum and the proximal part of the artificial femur. In the example, some fibrous tissue and bone tissue were found around the acetabular fixation part of the artificial acetabulum and the stem part of the artificial femur, and bony property was being obtained. In the comparative example, in addition to the findings similar to those of the example,
Polyethylene abrasion powder was scattered, foreign body giant cells were seen, and the appearance of continued inflammation was seen.

[0020]

As described above in detail, the artificial joint of the present invention is an artificial joint which replaces the joint part of the bone of the living body, and a lid is provided in the gap between the bone of the artificial joint fixing part to the bone and the implant. Since it has a coated adhesive portion for preventing the abrasion dust from entering between the bone and the artificial joint or between the bone and the cement, loosening can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an artificial acetabulum that is an example of an artificial joint of the present invention.

FIG. 2 is a cross-sectional view of an artificial femur that is an example of the artificial joint of the present invention. Explanation of symbols 11 ... Artificial joint (acetabulum), 12 ...
Abutment plate fixing part, 13 ... Slip part, 14 ... Coating adhesive part, 21 ... Artificial joint (femur), 22 ... Bone head, 23 ... Neck part, 28 ... Stem Department, 24
..Coating adhesive parts

Claims (1)

[Claims] 1. An artificial joint which replaces a joint part of a bone of a living body, the artificial joint having an artificial joint part and a coating adhesive part for covering a gap between the artificial joint part and the living bone. .