JPH0337057A - Artificial foot joint - Google Patents

Abstract

PURPOSE:To smoothly bend a joint with little resistance by fitting a rolling mechanism to a support member fixed at the end section of a tibia, and rolling bells and rollers of the rolling mechanism on the protruded support face of the support member on a talus side. CONSTITUTION:An artificial foot joint 11 mainly constituted of a protruded support member 5 on a talus 1 side, a recessed support member 7 on a tibia 3 side and a rolling mechanism 9 is inserted between the talus 1, shank member 3 and a fibula 4. When a force in the bending direction (arrow direction) is applied between the talus 1 and the tibia 3, balls 27 of the rolling mechanism 9 are rolled on a protruded support face 17. Balls 27 are continuously arranged in guide grooves 19 and 23, thus they can be endlessly moved when swayed. They are rolled and swayed not only to 30-40 deg. in a normal walking but also to about 60 deg., the movement is smooth, and they rarely have abrasion. The rolling mechanism 9 is stored in the recessed support member 7 side and located on the artificial foot joint 11, thus even if a foreign object is mixed on the sliding faces of balls 27, it is dropped. The artificial foot joint 11 can retain a long life.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an artificial ankle joint for replacing or repairing the ankle joint of the human body.

[Prior Art] Conventionally, as this type of artificial ankle joint, for example, lf, 1st
The devices shown in FIGS. 9 and 20 are known.

That is, a sliding bearing is provided in which a convex support member 102 made of ceramic (or metal) is fixed to the upper surface of a talus 100 of a human body, and a concave support member 108 made of resin such as high-density polyethylene is fixed to the lower surface of the tibia 106. This is a type of artificial ankle joint that performs a bending motion by sliding on the sliding surfaces of these members.

[Problems to be Solved by the Invention] However, in conventional artificial ankle joints, sliding resistance is large because the contact area of the sliding surface is large, and moreover, a large force is applied to the end of the concave support member 108. join. Therefore, with long-term use, the concave support member 108 may become attached to the tibia 10.
6 will be deformed, such as creating a gap, and the - layer sliding resistance will increase. For this reason, there is a problem in that the artificial ankle joint cannot perform a smooth bending action.

In addition, when the sliding resistance is large like this, the convex support member 1
When a metal material is used for 02, the sliding surface of the concave support member 108 is worn out and becomes rough after one long period of use, and this combined with corrosion of the metal member causes wear that scrapes the concave support member 108. The present invention aims to solve the problems of the above-mentioned conventional technology, which also had the problem of powder generation. The purpose is to provide an artificial ankle joint that is highly stable even when used.

[Means for Solving the Problems] An invention made to solve the above problems (an artificial ankle joint interposed between the talus and the tibia (in this case, an artificial ankle joint that is fixed to the end of the talus and supported in a convex shape) a first support member having a surface; a second support member fixed to the end of the tibia; and a plurality of rollers or spheres attached to the second support member and rolling on a convex support surface. It is characterized by having a rolling mechanism;

Here, as a configuration for attaching a rolling mechanism having spheres or rollers to the second support member (a means for continuously arranging one sphere in a groove and moving it endlessly, and a means for attaching the spheres or rollers to a movable retainer), It is possible to adopt a means for holding it rotatably and moving it while being guided by a groove or the like of the second support member.

In addition, the rolling mechanism (above) is formed in the shape of a drum, and a corresponding groove is provided on the convex support surface for positioning, so that it shifts relative to the convex support surface as the joint bends. It may be configured to prevent this.

The first support member, the second support member, the rollers and the spheres may be made of metal in addition to ceramics; in the case of ceramics, 1. t, alumina, zirconia, silicon nitride, sialon, silicon carbide, and composite materials of these different materials can be used. High hardness metals can be used.

In addition, as the material of the member that holds the rollers of the rolling mechanism (,
1. In the case of resin, ultra-high density polyethylene, polymethyl methacrylate, polyacetal and MC nylon can be applied, and in the case of metal, titanium alloy, stainless steel, cobalt-chromium and high carbon steel can be applied. can.

[Function] According to the artificial ankle joint of the present invention, the first support member is fixed to the end of the talus, and the second support member is fixed to the tibia. 1st
is interposed between the supporting member and the second supporting member. This rolling mechanism 1. t, has a plurality of spheres or rollers, and these spheres roll on the convex support surface of the first support member.

In other words, the balls or rollers of the rolling mechanism (upper) roll on a convex support surface in point or line contact, allowing for smoother flexion of the joint than in conventional techniques that slide with surface contact. can be done.

Furthermore, when a rolling mechanism is attached to the second support member on the tibia side, the rollers and spheres of the rolling mechanism are located on the upper side, so that even if wear particles are generated, they will move downward. There is little foreign matter entering rotating sliding parts such as rollers, and smooth rotation can be maintained for a long period of time.

[Example] An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a cross-sectional view showing an artificial ankle joint according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line a-a in FIG. 1.

In these figures, the talus 1, tibia 3 and fibula 4 of a human body are shown.
Convex support member on talus 1 side (first support member) on t between
5. An artificial ankle joint 11 mainly composed of a concave support member (second support member) 7 on the side of the tibia 3 and a rolling mechanism 9 provided between the convex support member 5 and the concave support member 7 is interposed. equipped. The convex support member 5 (upper part) is made of ceramics, and is fixed to the talus 1 with bone cement or the like at the fixation protrusion 13 formed on its lower surface and the joint surface 15 with the talus 1, and its upper surface is a convex support member. It is surface 17.

On the other hand, the concave support member 7 (9) is made of ceramics and is fixed to the end surface of the tibia 3 with bone cement or the like.

On the rolling mechanism 91, a recess 21 having three rows of guide grooves 19 is formed on the lower surface of the concave support member 7, and a fixing member 25 having a guide groove 23 continuous with the guide groove 19 is fixed to this recess 21. Then, the spheres 27 are continuously arranged in the guide grooves 19.23, and the spheres 27 are fixed with a fixed retainer 29, and the fixed retainer 29 is further fixed to the concave support member 7 via the fixing plate 31. It is constructed by doing the following.

Next, to explain the bending action of the artificial ankle joint 11 of this embodiment, the force in the bending direction (second
When the direction of the arrow in the figure) is applied, the sphere 2 of the 1 mm rolling mechanism 9
7 rolls on the convex support surface 17. This sphere 271
Since it is arranged continuously in the guide groove 19.23, it can be moved infinitely during rocking. Therefore, the artificial ankle joint with this structure has a swing angle of 30~30° during normal walking.
It rolls and oscillates not only 40" but also up to 60", and its movement is smooth and there is almost no wear.

In addition, since the rolling mechanism 91t is attached to the side of the concave support member 7, that is, located above the artificial ankle joint 1, even if foreign matter gets into the sliding surface of the sphere 27,
It will fall out from here. Therefore, the sphere 27 is not hindered by foreign matter and rolls smoothly and without causing wear.

Therefore, the artificial ankle joint of this embodiment] 1 (high reliability and long life can be achieved).

Furthermore, since the rolling mechanism 9 of the artificial ankle joint 11 can be assembled into the concave support member 7 and the convex support member 5 as two parts, the surgery can be performed easily as in the conventional art.

Various configurations described below can be considered as modifications of the above embodiment. In the following description, parts that are the same as or equivalent to those described above will be given the same numbers, and their descriptions will be omitted, and distinctive parts will be described.

■ First, as a modification of FIGS. 1 and 2, as shown in FIGS. 3 and 4, the guide groove 19a of the sphere 27 is
A similar effect can be obtained even if the sphere 27 is formed around the entire outer circumference of the fixing member 25, and furthermore, since the sphere 27 is integrated with the fixing member 25, it is easy to assemble the second layer.

■ The embodiment shown in FIGS. 5 and 6 (upper) The concave support surface 18 of the concave support member 7 is formed into a curved surface, and there are two
Row guide grooves 23b are provided, and the spheres 2 are inserted into these guide grooves 23b.
7 are consecutively arranged, and furthermore, spheres 27 are consecutively arranged on both sides thereof, and these spheres 27 are fixed with a fixed retainer 29 so as not to fall off.

■ Embodiment shown in FIGS. 7 and 8 (Top) Holding protrusions 33 are formed on both outer edges of the inner surface of the concave support member 7, and the concave support member 33 prevents the movable retainer 35 from falling off. 7, a through hole 37 for holding the sphere 27 is formed in this movable retainer 35,
Further, a stopper bin 39 is provided near the entrance to prevent the movable retainer 35 from coming off.

As a modified example of this, as shown in FIGS. 9 and 10, a curved convex support surface 7 and a concave support surface 18 are formed, and a movable retainer 35c is installed between both surfaces 17 and 18. Accordingly, the movable retainer 35c may be configured to have some play so that it can swing slightly in the left-right direction as shown in FIG.

(4) The four embodiments shown in FIGS. 11 to 18 (in which a roller is used instead of the sphere 27) will be described next.

That is, the rolling mechanism 91 shown in FIGS.
5, and guide grooves 47 and 49 for guiding the annular protrusion 41 are formed on the convex support surface 17 and the concave support surface 18. With this configuration (the upper roller 43 is positioned at the center of both support surfaces 17 and 18), it rolls smoothly.

Further, as a positioning configuration formed on the rollers 43 of the rolling mechanism 9, as shown in FIGS. 13 and 14, the rollers 4
An annular recess 51 is formed in the center of 3a, and a convex support surface 17
and a configuration in which support protrusions 53.55 are formed on the side of the concave support surface 18, and as shown in FIGS. Guide recesses 61, 6 are provided in the shaped support surface 17 and the concave support surface 18.
3 may be formed.

Further, as the rolling mechanism 9, as shown in FIGS. 17 and 18, needle rollers 43c are rotatably attached to a movable retainer 35d, and this is a retainer formed at the edge of the concave support surface 18. It may be configured such that the protrusion 33 prevents it from falling off.

It should be noted that the present invention is not limited to the configurations of the above embodiments, but may include combinations of characteristic elements of the above embodiments, such as the shape of the rollers, the combination of spheres and rollers, etc. Of course, various embodiments can be considered by appropriately combining the configurations.

[Effects of the Invention] As explained above, 1. According to the artificial ankle joint of the present invention (2) a second support member is fixed to the end of the tibia, a rolling mechanism is attached to this second support member, and this Since the balls and rollers of the rolling mechanism are rolled on the convex support surface of the first support member on the talus side, smooth bending of the joint is possible with low resistance.

Furthermore, since the rolling mechanism is attached to the tibia side, there is no chance of foreign objects getting caught, and stable flexion can be achieved over a long period of time.

[BRIEF DESCRIPTION OF THE DRAWINGS] Figure 1 is a cross-sectional view of an artificial ankle joint according to an embodiment of the invention, and Figure 2 is a cross-sectional view taken along line a-a of Figure 1.
The figure shows the cross section of the second embodiment.
Figure 5 is the cross section taken along line b. Figure 6 is the cross section taken along line c-c. Figure 7 is the cross section of the fourth example.
Figure 8 is a cross section taken along line dd. Figure 9 is a cross section of the fifth embodiment. Figure 10 is a cross section taken along line e-e in Figure 9.
The figure shows the cross section of the sixth embodiment.
The cross section of the f-line is the cross section of the seventh embodiment in Figure 13.
Figure 4 shows the cross section taken along line g-g in Figure 13. Figure 15 shows the cross section of the eighth embodiment. Figure 16 shows the cross section taken along line h-h in Figure 15. Figure 17 shows the ninth embodiment. The cross section of Figure 18 is i-
19 is a cross-sectional view showing a conventional artificial ankle joint. FIG. 20 is a cross-sectional view taken along line j--j in FIG. 19. 1... Talus 3... Tibia

Claims (1)

[Scope of Claims] 1. An artificial ankle joint interposed between the talus and the tibia, comprising: a first support member fixed to the end of the talus and having a convex support surface; and a first support member fixed to the end of the tibia. An artificial ankle joint comprising: a second support member; and a rolling mechanism that is attached to the second support member and has a plurality of balls or rollers that roll on a convex support surface.