JPH10146352A - Artificial bone implant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a stem hard to collide with a medullary cavity wall in operation, and safely and quickly perform an operation by constituting the stem to be inserted into a medullary cavity of a thighbone in an S shape in an outside plan view, raising the rear side of a center line of an S in a straight line shape, and eccentrically arranging a neck part. SOLUTION: An implant as a prosthetic tool of a hip joint is composed of a stem 2, a small head 8, a small head inserting body 7 and a support shell 6, and is formed as a spherical surface so as to be slidingly movable between the small head 8 and the small head inserting body 7. A front upper part of this stem 2 is formed as a curve R3, and is formed in a, circular arc shape, and a lower part is also formed backward as a curve R2, and the stem 2 is formed in an S shape in a side plan view by these curves R3 and R2. In the stem 2, when a center line of an S shape is denoted by an O line, the rear side rises in a straight line shape in a width T4 with the O line as the center, and a neck part 3 is arranged so as to be eccentric by a distance T5 from the O line. Therefore, the stem 2 is made easily movable, and a fear of damaging a medullary cavity wall is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial bone implant, for example, an artificial hip joint, that is, an artificial bone implant for connecting between the medullary cavity of the femur and the acetabulum.

[0002]

2. Description of the Related Art Conventionally, a technique relating to a hip joint prosthesis implant as a prosthesis for a femur and an acetabulum is known. For example,
No. 8, Japanese Patent Publication No. 31378/1989, Japanese Unexamined Patent Publication No.
Such techniques are described in Japanese Patent Application Laid-Open No. 3-272345, Japanese Patent Application Laid-Open No. 61-33660, and Japanese Patent Application Laid-Open No. 64-2645.

[0003]

However, even in a conventional femoral implant, a curve is formed in a stem portion as viewed from the lateral side as described in Japanese Patent Publication No. 1-3378. When viewed from the outside, the curve is curved forward in the upper part, but the lower part is also a “one circular arc” curved forward, and the problem is that the stem direction does not match the direction of the medullary cavity inside the medullary cavity. There was. In addition, the "one circular arc type" has a drawback that it easily moves along the curve during the operation and may damage the wall of the medullary cavity. The present invention is to solve the above-mentioned problems.

[0004]

The problem to be solved by the present invention is as described above, and the means to be solved will be described below. In the first aspect, the stem 2 to be inserted into the medullary cavity of the femur is formed into an "S" shape when viewed from the outside, and the center line of the "S" shape is defined as an O line. The posterior side of the line rises linearly with a width T4, and the neck 3 is an artificial bone implant arranged eccentrically by a distance T5 from the O line.

[0005] In the claims, the stem 2 to be prosthetic in the medullary cavity of the femur is an "S" type in which the upper part curves forward and the lower part curves backward when viewed from the outside of the femur. It is an artificial bone implant configured in a part.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The problems to be solved and means to be solved by the present invention are as described above. Next, the configuration of the artificial bone implant shown in the accompanying drawings will be described. As shown in FIGS. 1, 2, and 3, the artificial bone implant of this configuration is
1 shows an implant as a hip prosthesis. In the case of the hip joint prosthesis implant, the prosthesis comprises a stem 2, a small head 8, a small head insert 7, and a support shell 6,
A spherically slidable configuration between the small head 8 and the small head insert 7;
The hip joint is bent. The stem 2 is manufactured by sintering a metal material such as titanium or a titanium alloy. The porous layer on the upper portion of the stem 2 is constituted by a hemispherical portion a so as to enhance the bonding force with the femur.

A small trochanter collar 4 may be provided on the upper portion of the stem 2 close to the small head 8 to prevent the stem 2 from sinking into the femur. A greater trochanter collar 5 is provided at a position opposite to the smaller trochanter collar 4. The hemispherical portion a is configured so that a base made of a metal material such as titanium or a titanium alloy is not integrally baked after forming, but is formed integrally when forming the base of the alloy and then fired.

The neck 3 protrudes from the upper end, and the small head 8 of the neck 3 is fitted through a tapered hole. The small head 8
Is made of metal or ceramic, and a small head insert 7 that enables smooth bending is fitted around the small head 8 formed in a spherical shape. The small head insert 7 is shown in FIGS. 6 to 8 and is made of a synthetic resin or the like that slides well.

The support shell 6 is shown in FIGS. 9 to 12 and is made of a metal material such as titanium or a titanium alloy. A hemispherical portion a of the porous layer is formed for easy operation. In the present configuration, the porous layer is formed integrally with the hemispherical portion a by using a cold isotropic compression method or the like at the time of molding the base, and then fired to form the porous layer.

A locking post 6a protrudes from the support shell 6, and a bolt hole 6b formed in the locking post 6a is provided.
A screw is screwed on the acetabular and fixed between the screw hole and the opening of the acetabulum. A number of bolt holes 6d are also opened in the spherical portion of the support shell 6, and screws are screwed into the bolt holes 6d and fixed to the screw holes opened in the acetabulum. A fitting hole 6c at the center of the support shell 6 is a hole into which a locking projection 7a at the top of the small head insertion body 7 is fitted. Further, two locking projections 6e protrude from the lower surface of the support shell 6, and
The locking projections 6e are configured to be fitted and locked into two locking recesses 7b provided on the small head insert 7.

In the hip joint prosthesis implant of the present configuration, the hemispherical portion a constituting the porous layer must be integrally formed at the time of forming a base metal material such as titanium or a titanium alloy. As shown, molding is performed using a cold isotropic compression method or the like. In the cold isotropic compression method, molding is performed as follows. That is, the elastic form 9
A mold such as a stem 2 provided with a large number of hemispherical holes constituting a hemispherical portion a is formed as a female mold, and powder of titanium or a titanium alloy is poured from a hopper 10 into a female mold 9 of the stem 2. After closing the upper portion of the mold 9 with a lid, the mold 9 is placed in the pressure vessel 11, and a pressurized compressed liquid is injected into the pressure vessel 11 at room temperature by a pump. By the operation,
Pressure is applied isotropically from the periphery of the mold 9 and the shape of the stem 2 along the female mold of the mold 9 is completed.

In this configuration, the porous layer is formed of a bead sphere b
Therefore, since the hemisphere is formed by the hemispherical portion a without using the mold, the mold 9 can be formed and the mold 9 can be pulled out, so that it can be integrally formed by the cold isotropic compression method. As shown in FIG. 13, the hemisphere portion a is usually formed as a hemisphere having a radius, that is, a height of 250 to 500 μ. In addition, a continuous hemispherical portion may be used as shown in FIGS. 14 and 17, a high adjacent connecting portion may be formed as shown in FIG. 18, or a deep adjacent connecting portion may be formed as shown in FIGS. May be configured. The configuration of the hemispherical portion a can be various shapes as long as the mold 9 can be removed after molding.

Next, regarding the shape of the stem 2, FIG.
This will be described with reference to FIG. The stem 2 gradually becomes thinner toward the lower end, and its angle is about Θ = 2 to 3 degrees. The flange 3 is inclined and protrudes toward the acetabulum of the femur, and is formed by a curve R1 reaching the minor trochanter collar 4 toward the inner surface. That is, in FIG. 19, the taper Θ is continuous from the lower end of the stem 2 to the height of T1, and from the end of T1, about T2 = 50 mm reaches the small trochanter flange 4 as a curve R1 about R2. . Shape 6 shows a stem shape without a collar. Conversely, the outer shape of the stem 2 of FIG. 19 is configured to gradually increase in thickness upward at an angle of about Θ / 2.

Next, the configuration of the "S" type will be described with reference to FIG. A curved portion R3 is formed on the upper portion of the front surface of the stem 2 to form an arc shape, and the lower portion of the stem 2 forms a curved portion of R2 toward the rear. Therefore, the upper curve R3 and the lower curve R2 form an "S" shape in side view. Assuming that the center line of the "S" type is the O line, the rear side linearly rises with a width T4 around the O line, and the neck 3 is arranged eccentrically by a distance T5 from the O line. ing.

[0015]

As described above, the present invention has the following advantages. Since the stem is formed in the "S" shape as in claim 1, it is possible to prevent the collision with the wall of the medullary cavity at the time of the operation, and to perform the operation safely and quickly. As in claim 2, in the artificial bone implant constituting the hip joint, the stem 2 inserted into the medullary cavity of the femur has an upper part curved forward and a lower part curved backward in a lateral view of the femur. The following effects are achieved because of the "S" -shaped configuration. Conventionally, the stem was curved, but since the upper part was not curved forward, when the center of gravity was applied to the front when walking, the small trochanter collar and the greater trochanter collar There was a problem that an unacceptable pressing force was generated. In the present invention, the pressing force is received at the upwardly curved portion, and a hip joint prosthesis implant capable of receiving weight on average as a whole can be obtained. In addition, since the stem shape approximates the medullary cavity shape of the living femur, excellent performance can be obtained in both long-term and short-term fixation with an unspecified number of femurs.

[Brief description of the drawings]

FIG. 1 is an overall view of an implant as a right femoral prosthesis in an artificial bone implant.

FIG. 2 is an overall cross-sectional view of a portion including a neck 3, a small head 8, and a support shell 6.

FIG. 3 is a lateral view of the right femur.

FIG. 4 is a bottom view of the support shell 6;

FIG. 5 is a side view of the same.

FIG. 6 is a plan view of the small head insert 7;

FIG. 7 is a side view of the same.

FIG. 8 is a bottom view of the same.

FIG. 9 is a bottom view of the support shell 6.

FIG. 10 is a side view of the support shell 6.

11 is a plan view of the support shell 6. FIG.

FIG. 12 is another side view of the same.

FIG. 13 is a side view of a hemispherical portion a constituting another porous layer.

FIG. 14 is a side sectional view showing another configuration of the hemispherical portion a.

FIG. 15 is a side sectional view showing another configuration of the hemispherical portion a.

FIG. 16 is a side sectional view showing another configuration of the hemispherical portion a.

FIG. 17 is a side sectional view showing another configuration of the hemispherical portion a.

FIG. 18 is a side sectional view showing another configuration of the hemispherical portion a.

FIG. 19 is a front view of the stem 2 of the right femoral implant.

FIG. 20 is a side view of the same.

FIG. 21 is a continuous drawing showing a substrate forming method by cold isostatic compression.

FIG. 22 is a continuous drawing showing a substrate forming method by cold isotropic compression.

FIG. 23 is a continuous drawing showing a substrate forming method by cold isostatic compression.

FIG. 24 is a continuous drawing showing a substrate forming method by cold isostatic compression.

FIG. 25 is an enlarged perspective view showing a case where a porous layer is formed by a conventional bead ball b.

[Explanation of symbols]

 2 stem 3 neck

Claims (2)

[Claims] 1. A stem 2 to be inserted into a medullary cavity of a femur.
Is formed in an “S” shape when viewed from the outside, and the center line of the “S” shape is defined as an O line, and the rear side of the center line O line has a linear width T.
An artificial bone implant ascending at 4 and wherein the neck 3 is arranged eccentrically by a distance T5 from the O line. 2. A stem 2 to be prosthetic in the medullary cavity of the femur.
An artificial bone implant characterized in that, when viewed from the lateral side of the femur, the upper part is curved forward, and the lower part is curved backward.