JPH02224658A - Artificial joint - Google Patents

Abstract

PURPOSE:To allow mounting of the optimum joint member in a short period of time by forming mounting parts, such as grooves and dovetail grooves, to the artificial joint member and inserting an approximately U-shaped adjusting plate to the mounting parts. CONSTITUTION:One to several pieces of the U-shaped grooves 4 are provided in circumferential, before and behind directions and side face direction in a stem part 3 of the tibia member 1. The adjusting plate 5 for adjusting the thickness is provided with a notch 6 corresponding to the groove 4. The thickness of the tibia member 1 is adjusted as desired by inserting one to several sheets of the plate 5 meeting the thickness of the gap with the bone in the arrow direction. The shape of the adjusting plate 5 may be the shape of a sliding part 2 or the shape meeting the bone cutting plane of the tibia and the material consists of metallic materials, such as stainless steel and titanium alloy, or ceramics, etc. The plate corresponding to the chipping shape of the bone may be inserted if there is the chipping of the bone near the central intercondylic part of the tibia.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention restores the original function of joints that have been severely deformed due to rheumatism, osteoarthritis, etc., or that have been destroyed due to traffic accidents, disasters, tumors, etc. It relates to various types of artificial joints used to restore normal function.

[Prior art and its problems]

In conventional artificial joints, when replacing joint parts that have lost function due to various diseases, the acetabulum side and proximal end of the femur are replaced in the hip joint, and the distal end of the femur and the proximal end of the tibia in the knee joint. After performing osteotomy, curettage, or rimming on each side to match the shape of the joint member, the joint member is attached to the removed portion by press-fitting, fixing with screws, or using bone cement. ing.

Fig. 6 shows the stem part S of the artificial hip joint and the state in which the stem part S is attached to the cut bone when attaching the stem part S to the femur F. The femur F is shaped into an optimal shape for mounting the stem portion S so as to show the state of the proximal end of the femur F, which has been osteotomized at the neck of the bone F and reamed inside the medullary canal. Also the 7th
The figure shows the femoral component that constitutes the artificial knee joint and the shape of the distal end of the femur F, which has been cut to accommodate this femoral component. This is a diagram for explaining the method for attaching the knee joint member G to the end. In the osteotomy performed when attaching these artificial joints, it is important to maintain the joint function that the joint originally has. In order to place the artificial joint components in a state that can be reproduced, the question is how to make bone cuts in an accurate shape.In other words, this means making accurate bone cuts that correspond to the shape of each joint component. If not, the range of motion may be restricted due to tension or loosening of the muscles and ligaments surrounding the joint members, or the joint members may loosen, shift, or sink during long-term use, making it impossible to reproduce the original joint. As a result, each joint member must be removed and replaced again. Another reason why accurate osteotomy is important is that if the osteotomy is incomplete and cannot be placed accurately, uneven loads will be applied to each joint member itself. Moreover, excessive stress is applied even to parts to which no load is normally applied. This causes deformation, wear and tear of each joint member, and even bone resorption around the attached joint member. As a result, the lifespan of the artificial joint will be shortened.

For the above reasons, it is clear that it is important to perform accurate osteotomy, and various osteotomy jigs have been devised to perform accurate osteotomy. In order to perform osteotomy on the damaged bone, it was difficult to set up the jig, and the osteotomy jig sometimes slipped during the surgery, so experience and intuition had to be relied upon.

In cases of severe deformity, bone defects may occur even after osteotomy, making it extremely difficult to perform accurate osteotomy that perfectly corresponds to the shape of the joint member.

In order to eliminate these inconveniences, a method has been used in which a large number of joint members of different sizes and thicknesses are prepared, and during the surgery, the joint member that matches the amount of bone cut is selected and used. was. However, this requires a large amount of preparation and handling of the joint components, and a correspondingly large amount of osteotomy jigs, making it difficult to attach the optimal joint components in a short period of time. It was extremely difficult.

[Means for solving problems]

In order to solve the above-mentioned problem, a mounting part is installed on the part of the joint member that comes in contact with the osteotomy surface, which is a substantially U-shaped member and can be fitted with an adjustment plate that has a U-shaped groove or a grooved structure around the periphery. The length and thickness of the joint member can be adjusted by inserting adjusting plates of different thicknesses into this, eliminating the gap between the joint member and the osteotomy surface, or preventing deformation. In cases where the bone loss is severe or there is a large amount of bone loss, only that portion is prosthesized to correct the shape of the joint member.

[For production]

1. The thickness and height of the joint member can be adjusted, and it is possible to select a joint member that matches the shape of the osteotomy instead of the conventional osteotomy that matches the joint member.

2. Since there is no gap between the joint member and the osteotomy surface, it is possible to attach the joint member more accurately and firmly.
During long-term use, it prevents loosening, shifting, and sinking, and allows stable joint function to be reproduced.

3. Even if there is a defective part such as a tumor, the defective part can be corrected with the joint member into a prosthetic shape, thereby minimizing the amount of osteotomy and allowing as much normal bone as possible to remain.

4. Instead of preparing a large number of joint members of different shapes and sizes as in the past, it is only necessary to prepare several types of plates for adjusting the thickness, making it easier to disinfect and procure surgical instruments before surgery. It becomes easier.

〔Example〕

The present invention will be explained below by way of examples with reference to the figures.

FIG. 1 shows a perspective view of a tibial component 1 as a joint component constituting an artificial joint (artificial knee joint) according to the present invention, and this tibial component 1 constitutes an articular surface with a femoral component (not shown). The sliding part 2 is inserted into the tibial bone cavity, and the fixation of the artificial joint is improved.
It is composed of a stem portion 3 for obtaining stability.

The sliding part 2 has a sliding surface made of polyethylene, high-density polyethylene, etc. in order to slide on a femoral bone member (not shown) made of metal or ceramic, and the stem part 3 has a sliding surface made of polyethylene, high-density polyethylene, etc. to reinforce the sliding part 2. , made of metal or ceramic.

Furthermore, the stem portion 3 of the tibial component 1 is provided with one to several U-shaped grooves 4 in the circumferential, anteroposterior and lateral directions, and there is a groove for adjusting the thickness. The adjustment plate 5 is provided with a notch 6 corresponding to the groove 4 described above. The thickness of the tibial component 1 can be arbitrarily adjusted by inserting one to several plates 5 in the thickness of the gap between the tibia and the bone in the direction of the arrow in the figure. The shape of the adjustment plate 5 may be the same as the shape of the sliding part 2 or the shape that matches the tibial osteotomy surface, and the material may be stainless steel,
It is made of metal materials such as titanium alloys or ceramics. Note that if there is a bone defect near the central intercondylar part of the tibia, a plate corresponding to the shape of the defect may be inserted.

FIG. 2 shows another embodiment, in which adjustment plates 5 having various thicknesses are inserted into grooves 4a formed around the sliding portion 2 of the tibial component l, as a mounting structure for the adjustment plates 5. , a notch 6 having a slope 5a adapted to the groove 4a is provided. In addition, such a groove 4a and slope 5a
and may be formed on the opposite member, and
The grooves 4 and the grooves 4a may be formed on the outer periphery of the side surface of the sliding portion 2. Further, in the above embodiment, the adjustment plate 5 is fitted from the front and rear directions of the joint member, but the invention is not limited to this, and as shown in FIG. 5 may be inserted.

In addition, for a tibia T whose joint sliding surface has been deformed due to varus deformity, etc. as shown in Figure 4, it is common to make a straight osteotomy at an angle. In order to minimize the amount of cut, the bone cut is made in a straight line in the diagram.

In this case, a recess will be created at the end due to the bone defect A, resulting in an unstable state even if the tibial component 1 as shown in Fig. 1 is installed. As shown in FIG. 3 above, by using a groove 4a provided in the left and right direction of the sliding portion 2 of the tibial component 1, a prosthetic-shaped plate that is shaped to match the shape of the bone defect only on the left side can be obtained. 5' should be installed. In this way, there is no need to perform osteotomy on the osteotomy surface where a large amount of osteotomy is required, and it is possible to leave as much normal bone as possible. Furthermore, FIG. 5 shows an artificial hip joint, in which a groove 4 is provided at the neck N of the stem S, and the distance between the neck N and the center of the ball B is adjusted by fitting an adjustment plate 5. can do. This adjusts the tension of the muscles and ligaments around the joint member to the most appropriate state, ensuring a larger range of joint motion and providing a more stable post-surgery wearing condition.

In the above embodiment, an example in which only one flat adjustment plate is inserted into the joint member is explained, but the invention is not limited to this, and a plurality of adjustment plates may be used in combination. It is also possible to use an adjustment plate with partially different thicknesses, for example - thinner on the left side and medium thicker on the other side.

〔Effect of the invention〕

Providing a groove or grooved attachment part on the artificial joint member like a ridge,
By inserting an adjustment plate into this attachment part, an artificial joint can be created that can eliminate the gap between the osteotomy surface and the bone defect, and can also adjust the thickness and height of the joint member.
It is now possible to adjust the neck length etc. arbitrarily, and only requires a small amount of bone cutting, making it an even better artificial joint that aims to reproduce the original joint function and contributing to human welfare. The place is large.

[Brief explanation of the drawing]

Figures 1, 2, 3, and 5 all relate to embodiments of the present invention, and are diagrams for explaining the structure for inserting adjustment plates into each joint member, and Figure 4 is a diagram for explaining the structure for inserting adjustment plates into each joint member. It is a figure for explaining the osteotomy surface when applying the artificial joint of this invention. FIG. 6 is a diagram illustrating a method for attaching a conventional artificial hip joint member to a femur that has been osteotomed and reamed, and FIG. 7 is a diagram illustrating a method for attaching a conventional artificial knee joint member to an osteotomized femur. FIG. 8 is a diagram for explaining a method for attaching a conventional artificial knee joint member to an osteotomized tibia.

Claims (1)

[Claims] An artificial joint characterized in that an attachment part such as a groove or groove is formed in an artificial joint member, and a substantially U-shaped adjustment plate is inserted into the attachment part.