JPS596048A - Artificial crotch joint - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to improvements in artificial hip joints.

The above-mentioned artificial hip joint consists of an artificial femoral head and an artificial glenoid fossa.
An example of a conventionally known artificial femoral head is a shaft 4a inserted into a human bone 2, as shown in Figure 1.1.
It is constructed by attaching a femoral head 6 to a stem 4 consisting of a tapered pin 4b and a tapered pin 4b. An artificial glenoid fossa (not shown) is slidably fitted into the femoral head 6.

In the conventional example described above, the femoral head 6 and stem 4 can be separated, so that the femoral head 6 and/or the stem 4 can be replaced as necessary.

By the way, the materials of artificial femoral heads and artificial glenoid fossas have changed from metals to synthetic resins, and further from synthetic resins to ceramics and the like.

This is because metals have poor compatibility with the human body, and synthetic resins have insufficient wear resistance.

However, even in the case of ceramics, when the artificial joint is used for a long time, considerable wear occurs only near the top of the femoral head 6 (for example, after 100 hours of use, about 25 microns of wear occurs).

However, since ceramics are generally brittle, when the full weight of the patient is applied to the artificial femoral head due to an impact, the impact force tends to fracture the femoral head.

The present invention focuses on the fact that the above-mentioned problems occur due to the fact that the femoral head of the artificial femoral head is fixedly attached to the stem. This was done with the aim of providing an artificial hip joint that does not require

To achieve this objective, in the present invention, the femoral head does not always contact the glenoid prosthesis at the same location, but changes depending on use, and the femoral head is relative to the columnar part of the stem. The reason is that it is held by a stem so that it can be displaced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in more detail based on the drawings.

In Figure 2, the stem 14 has a shaft portion 14a and a columnar portion 14b, and is made of a metal material with suitable swirl. The shaft portion 14a is inserted into the insertion hole 12a of the bone 12, while a cup-shaped cylindrical hole 22 is bored in the columnar portion 14b. Inside the cylindrical hole 22 are a disc spring 24 and a washer 26.
A spherical bushing 28 and a spherical bushing 28 are sequentially inserted, and the ball 16 as a femoral head is rotatably held by the spherical bushing 28 having a concave spherical surface, like a ball in a ballpoint pen.

The artificial glenoid fossa used in combination with the artificial femoral head 30 is no different from the conventional one, so illustration and description thereof will be omitted.

In the artificial femoral head 6,0 having the above configuration, the stem 14
The advantage of separating the femoral head 16 and the femoral head 16 is the same as that of the conventional example (Kari, Figure 1). In addition, when using the artificial joint (when bending), the femoral head 16 contacts an artificial glenoid fossa (not shown) and rotates in any direction while being guided by the spherical bush 28. That is, the artificial glenoid fossa of the femoral head 16 rotates in any direction. The contact area for the femoral head 16 is the entire surface of the femoral head 16. Therefore, the femoral head 16
Even though it is made of ceramics like before, it no longer wears out in specific parts.

In addition, when a high load is applied to the artificial femoral head 60 in an impactful manner, the ball 16 is pushed into the hole 22 and the disc spring 24 bends to absorb and alleviate this impact force, unlike the conventional method. This also prevents the femoral head 16 from being crushed.

Further, a normal stainless steel ball can be used as the femoral head 16, and commercially available spherical bushings 28, countersunks 24, etc. can be used, so that not only is workability excellent, but cost reduction is achieved.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, a rod 32 extends from the femoral head 16.
is fitted into a drum-shaped member 34 having a convex spherical surface,
This member 64 has a spherical bushing 36 of the spear 2 with a concave spherical surface.
It is swingably held by. Spherical bush 36
A ring member 38 is interposed between the disc spring 24 and the disc spring 24 .

In this embodiment, when the artificial hip joint is used, the artificial femoral head 301 swings in any direction about the rod 32, so the contact area of the femoral head 16 with the artificial glenoid fossa (not shown) is not only the top but also the surrounding area. This prevents only specific parts from wearing out. Note that the impact force is absorbed and alleviated by the disc spring 24, as in the above-mentioned embodiment of the fang 1.

Note that when the rod 52 is erected on the femoral head 16 as in the second embodiment, only the upper hemispherical surface actually contacts the artificial glenoid fossa, so the lower part of the femoral head can have any shape. It is also possible to deform it into a columnar shape (for example, into a columnar shape) or to remove it. Furthermore, in each of the above embodiments, the material of the femoral head may be metal such as stainless steel in addition to ceramics.

Further, in each of the above embodiments, the femoral head 16 is a solid ball, but it may also be a hollow pole.

Furthermore, if the surface of the femoral head 16 is lubricated and supplied, this lubricant will spread to the spherical bushing 28, 34 and the artificial glenoid fossa (not shown), and the friction between the femoral head, the spherical bushing, and the artificial glenoid fossa will increase. : Becomes smaller.

As detailed above, according to the present invention, the femoral head will not be worn out in a specific part of the femoral head, or the femoral head will not be fractured due to impact force, and the femoral head can be used permanently without having to be replaced. This means that an artificial hip joint that can be used can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional example; Fig. 2 and Figs. 2 and 6 respectively show embodiments of the fang 1 and fang 2 of the present invention; Fig. 1 is a sectional view corresponding to Fig. 1; [Explanation of symbols of main parts]

Claims (1)

[Scope of Claims] 1. An artificial joint consisting of an artificial femoral head in which a stem and a femoral head are separate, and an artificial glenoid fossa that is slidably fitted onto the femoral head, wherein the femoral head is disposed within a columnar part of the anterior stem. The femoral head is rotatably supported by a supporting member, which is displaceably attached to the columnar portion via an elastic member, and the supporting member allows the femoral head to move in three dimensions. 1. A hip joint prosthesis, characterized in that the elastic member is capable of relaxing and absorbing the impact force applied to the artificial femoral head. 2. The artificial hip joint according to claim 1, wherein the femoral head is a spherical body, and the support member is a spherical bushing rotatably holding the spherical body. 3. The femoral head is a spherical body with a rod projecting in the radial direction, while the support member is a spherical bushing, and a drum-shaped member fitted to the rod is tiltably held by the spherical bushing. An artificial hip joint according to claim 1'1.