JPH0675583B2 - Artificial joint - Google Patents

Description

TECHNICAL FIELD The present invention relates to an artificial joint that artificially prostheses a joint part of a living body and restores its function and shape.

[Conventional technology]

Replacement surgery to remove the joint part and prosthesis with an artificial joint when joint function is impaired due to lesions in the joint part due to bone degeneration such as trauma due to traffic accident or rheumatism, tumor, etc. and healing and recovery are unlikely Is being done.

As an artificial joint used at that time, for example, in the case of a hip joint, as shown in Japanese Patent Application Laid-Open No. 58-206745, a socket is fixed to the hip bone and a head ball which is rotatably accommodated in the socket is provided at one end. At the same time, there has been one that is configured with a stem portion that is configured to be inserted into the femur at the other end.

Further, in the case of an ankle joint, a tibial fixing member fixed to the tibia, a sliding member fitted to the tibial fixing member, and abutting on the sliding member as seen in JP-A-58-22052. It consisted of a talus fixation member that is fixed to the talus.

Other artificial knee joints, elbow joints, etc. are used.

[Problems to be solved by the invention]

Human joints, particularly hip joints, knee joints, and ankle joints, in addition to the weight of the living body, may momentarily exert several tons of force depending on the joint portion due to the muscle force acting on the joint portion. Therefore, the original joint of the living body has not only hardness but also flexibility to some extent, and has a function of absorbing and absorbing pressure and impact.

However, in the case of artificial joints, since they are made of ceramics, metals, etc., they are not flexible and structurally have no part that absorbs impact. Therefore, originally absorbed by the joint,
The shock to be buffered is transmitted as it is, loosening occurs at the joint between the joint member and the cement or the joint between the joint member and the bone, or the sliding surface of the two joint members is damaged. It had an adverse effect and shortened the life of the artificial joint. In addition, since the components of the artificial joint must be hard members that can withstand impact, the balance with other bones of the living body is poor and the joint or
There was also a drawback that the bones of other parts were easily broken.

[Means for solving problems]

In view of the above, the present invention provides at least one of the proximal joint member and the distal joint member with a slit as a cushioning mechanism in order to absorb and cushion the pressure and impact applied to the joint.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a hip joint. The stem M, which is a distal joining member, has one end joined to the femur and the other end is provided with a head ball K. The head ball K is rotatably accommodated in a socket S which is a proximal joint member, and the socket S is composed of a plastic body P that contacts the head ball K and an outer frame member C.

A slit A is provided in the plastic body P as a cushioning mechanism, and the slit A elastically deforms to absorb and cushion the pressure and impact between the femur and the lumbar region. Considering the direction in which pressure and impact are applied, the slit A has a curved upper portion as shown in the figure. Further, by providing the stem M with the slit A'in the long axis direction, it is possible to absorb and buffer pressure and impact in the bending direction applied to the stem M.

FIG. 2 shows an example of an artificial knee joint.

The femur fixing member D is connected to the protruding sliding member T by the fulcrum pin B, and the tibial fixing member E joined to the protruding sliding member T is provided with the slit A as a buffer mechanism. By elastically deforming the slit A, it is possible to absorb and buffer pressure and impact between the femur and the tibia.

FIG. 3 shows an embodiment of the ankle joint. Tibial fixation member F
A slit A is provided as a cushioning mechanism in the sliding member H joined to and is brought into contact with the talus fixing member G. The pressure and impact between the talus and tibia are absorbed and buffered by the elastic deformation of the slit A.

By the way, the slit A is a flat through hole extending in a direction perpendicular to the direction in which pressure or impact is applied. The slit A absorbs and buffers the pressure and impact applied to the joint, and causes significant deformation even when impact is applied. It must be sized appropriately to hold the joint without it. Of course, depending on the material and shape, for example, metal material (vitalium)
The length of the slit in the one composed of 2 to 6 cm,
The thickness is preferably within the range of 0.2 to 7 mm. Further, as a method of forming the slit, for example, a through hole is opened with a drill or the like, and the slit is expanded. Therefore, it is desirable to provide the slit in the member made of metal or plastic from the viewpoint of the ease of forming the slit and the effect as the cushioning mechanism.

〔The invention's effect〕

As described above, according to the present invention, at least one of the proximal joint member and the distal joint member is provided with a slit as a cushioning mechanism to absorb pressure and impact applied to the joint,
It can be buffered and does not damage the loosening of the joint between the joint member and the cement or the joint between the joint member and the bone or the sliding surface of the two joint members. Further, it is possible to provide an artificial joint that avoids damage to the artificial joint itself, has a long life, and is closer to the original joint of the living body.

[Brief description of drawings]

1, 2, and 3 are partial cross-sectional views of an artificial joint according to an embodiment of the present invention. FIG. 1 shows a hip joint, FIG. 2 shows a knee joint, and FIG. 3 shows an ankle joint. It represents. A, A ′: Slit, S: Socket M: Stem, D: Femur fixing member E: Tibia fixing member, F: Tibia fixing member G: Talar fixing member

Claims (1)

[Claims] 1. A joint having a proximal joint member joined to a proximal bone and a distal joint member joined to a distal bone, wherein at least one joint member is provided with a slit as a cushioning mechanism. Characteristic artificial joint.