JPS6232021Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an artificial ankle mechanism devised to prevent dislocation.

Conventionally, artificial ankle joint mechanisms consisting of a tibial component and a talar component have been widely used in the medical field, but because the talar component has a semi-cylindrical shape, it is prone to dislocation, especially in cases of central dislocation. Because the support of the low acetabulum was weak, there was a possibility that the tibial component might loosen or the artificial joint might prolapse into the pelvis. Furthermore, the ankle joint mechanism is relatively large, and it is desired to make it smaller. Therefore, the purpose of this invention is to provide an artificial ankle mechanism that can be used satisfactorily even for ankle joint disorders.

This idea will be explained below.

This invention relates to an artificial ankle joint mechanism consisting of a tibial component and a talar component, in which the joint surface of the tibial component is concavely curved in one direction, and also concavely curved in a direction perpendicular to the one direction. Two parallel curved surfaces are provided, and a concave portion is provided at the center of the top of the talar component to engage with the junction of the two curved surfaces to prevent dislocation of the tibial component and the talar component. This is what I did.

1A-C and 2A-C respectively show a tibial component 10 showing one embodiment of this invention.
and a talar side component 20 which receives the bottom surface of this tibial side component 10 at its top.The bottom of the tibial side component 10 made of ultra-high molecular weight polyethylene, for example, has two parallel concave curved grooves 11 and 12. are provided (FIG. 1C), and these curved grooves 11 and 12 are each curved in an arc shape in the longitudinal direction as shown in FIG. 1B. The curved grooves 11 and 12 are curved with the same curvature, and the level of the tangent line 13 and the level of the ends 14 and 15 of the curved grooves 11 and 12 are almost the same. Further, at the top of the tibial side component 10, there is provided a protrusion member 16 that is a stepped shaft that minimizes the amount of bone removed and prevents loosening between this component, bone cement, and cancellous bone. The joint member is fitted into a hole in a joint member such as a bone, and is connected to the joint member. For similar reasons, the talar component 20 is also provided with a shaft 23 extending to the talus or calcaneus.

On the other hand, on the top of the talar component 20 made of stainless steel 316L, for example, two convex portions 21 and 22 are provided in parallel to engage the curved grooves 11 and 12 of the tibial component 10, respectively (see Fig. 2B). ), the convex portions 21 and 22 are each curved into a substantially semicircular shape as shown in FIG. 2A. A connecting piece 23 is vertically provided at the bottom of the talus component 20 to be attached to a hole in another joint member. Note that the curvature of the curved grooves 11 and 12 of the tibial component 10 and the convex portions 21 and 2 of the talar component 20
The curvatures of No. 2 are sloped to match the physiological curvature of human bones. Moreover, these tibial side component 10 and talus side component 20
are made of metal and are resistant to wear.

In addition, in order to improve the range of motion (range of motion) of the ankle joint, especially dorsiflexion, the front and rear ends of the tangent line 13 are rounded 13.
A, 13B are attached, and each component 1
There are grooves 1 on each side to make it easier to hold 0 and 20.
0A and 20A are provided around it.

In such a configuration, when forming an ankle joint mechanism, the curved grooves 11 and 12 of the tibial component 10 are positioned so that they are in contact with the convex portions 21 and 22 at the top of the talar component 20, and the grooves are parallel to each other. A mechanical joint is obtained between the joint member connected to the projection member 16 of the tibial component 10 and the joint member connected to the joint piece 23 of the talar component 20. Thereby, the tibia side component 10 and the talus side component 20 form an ankle joint mechanism with respect to the upper and lower joint members. In this case, two parallel curved grooves 11 and 12 are formed in the bottom of the tibial component 10, and the top of the talar component 20 that engages with these grooves is also sloped with a similar curvature. Since two parallel convex portions 21 and 22 are provided,
The contact parts of the joint mechanism will not shift forward, backward, left or right, causing dislocation symptoms.

Furthermore, FIGS. 3A to 3C show other examples of the tibial component 10 of this invention,
The curved grooves 11A and 12A are similarly provided on the bottom surface, but the level of the tangent line 13 is lower than the ends 14 and 15 of the curved grooves. That is, the central portion (tangential line 13) of the bottom surface of the tibial component 10 is formed at an acute angle, and the top portion of the talar component 20 that engages therewith also has convex portions 21A that are inclined toward the ends. and 22A are provided. Even in this manner, dislocation of the joint mechanism can be prevented, and the positioning for coupling the tibial component 10 and the talar component 20 can be easily performed.

As described above, according to the artificial ankle joint mechanism of this invention, since the bottom surface of the tibial component and the top of the talar component are formed with uneven surfaces and are connected to each other, positioning can be easily performed, and The coupling effect of the unevenness can prevent the occurrence of dislocation effects such as subluxation and complete dislocation. As shown here, since it is easy to obtain bone freshness, dislocation will not occur even when used on the sphenoid bone, pubic bone, ischial bone, etc. Furthermore, since the tibial and talar components are engaged by curved concavities and convexities, the tibial and talar components can be made smaller, and the amount of foreign material (metal) used can be reduced compared to that of conventional ankle joints. It has the advantage that it can be made much smaller than a conventional mechanism.

When the ankle joint is severely damaged due to inflammatory disease, degenerative disease, or bone tumor, it is effective to replace it with the artificial ankle joint of this invention.

[Brief explanation of the drawing]

Figure 1A is a plan view showing one embodiment of the tibial component used in this invention, Figure B is a front view, Figure C is a side view, and Figure 2A is an implementation of the talar component used in this invention. Front view showing an example, figure B
3 is a side view, FIG. 3 C is a bottom view, FIG. 3 A is a plan view showing another embodiment of the tibial component used in this invention, FIG.
Figure A is a side view showing another embodiment of the talar side component used in this invention, Figure B is a front view, and Figure C is a front view.
is a bottom view. DESCRIPTION OF SYMBOLS 10... Tibial side component, 11, 12... Curved groove, 20... Talus side component, 21, 22... Convex part, 23... Connecting piece.

Claims (1)

[Claims for Utility Model Registration] (1) In an artificial ankle joint mechanism consisting of a tibial component and a talar component, the articular surface of the tibial component is curved concavely in one direction and perpendicular to the one direction. Two parallel curved surfaces are provided that are concavely curved and inclined in the direction and have an acute angle in the center, and the talar component is provided with two parallel curved surfaces that are formed at an acute angle at the top center thereof and that engage with the junction of the two curved surfaces. a curved concave portion that fits with the two parallel curved surfaces of the tibial component;
An artificial ankle joint mechanism, characterized in that the curved surfaces of the concave portions of the talar side components each have an inclination that matches the curvature of the bone. (2) The artificial ankle joint mechanism according to claim 1, wherein both ends of the joint between the two curved surfaces are rounded and curved. (3) The artificial ankle joint mechanism according to claim 1, wherein the concave portion of the talar side component is curved in a convex manner in accordance with the one direction.