JPS5817614B2 - Connector for living bones - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a connecting device for connecting and fixing an artificial joint, a fastening member, and other members to a living bone.

In the medical field, it is necessary to fix artificial joints to living bones such as human bones, and in order to connect fractured parts,
There are cases where it is necessary to fasten an internal fixation device such as a fracture fixation plate to a human bone or other living bone using screws or the like.

Conventionally, when fixing components such as an artificial hip joint or an artificial knee joint to a human bone, bone cement 3 made of acrylic polymer is usually used as an adhesive between the component 1 and the human bone 2, as shown in FIG. It is being

However, bone cement generates heat of about 80° C. during the polymerization process, which damages living tissues and causes joints to loosen over time.

In addition, in the case of repairing a bone graft, as shown in Fig. 2, internal fixation devices such as a fracture fixation plate 4 are conventionally fastened to the human bones 2a and 2b using stainless steel screws 5. However, stress in the threaded portion of the human bone damages the human bone over time, resulting in loosening of the fastening portion as described above.

For these reasons, there is a desire to develop a connecting tool that allows easy and reliable connection of living bones and components, and that does not cause damage to living bones.

This invention was made in view of the above-mentioned circumstances, and it is possible to easily and reliably connect living bones and components without damaging the living bones, and without causing deterioration of the connection parts over time. It is an object of the present invention to provide a connecting device for a living bone part that does not cause damage to the living body.

The details of this invention will be explained below with reference to one embodiment.

In FIG. 3, reference numeral 11 denotes an artificial joint as an example of a connecting device, which is used for connecting and fixing to a human bone 12.

At least the stem portion 14, which is the connecting portion of the artificial joint 11, is made of shape-memory metal.

The shape-memory metal used has a transformation point at a temperature that does not damage living tissue, for example, 40° C. or lower.

The shape-memory metal used here is formed into a predetermined shape above the transformation point, stored in a different shape below the transformation point, and later returns to its original shape when heated below the transformation point.
It is a metal with a so-called shape memory effect, for example, as described in the paper, ``5hape M'' written by Geff P'erkins.
memoryEffects in Alloysj (
Melallurgical Soc, of AI
ME) (Plenum Publ, Co: , 197
5) and other papers, such shape memory metals include Cu-A I-N i, Ti-
Ni.

N i -A I, Cu-Z n, A u-Cd,
Alloys such as Au-Cu-Zn and Ag-Zn are known and commercially available, but here, 50%N
An i-50 Ti alloy is used.

This 50% Ni-50% Ti alloy has a transformation point at about 40°C.

First, as shown in FIG. 4a, the stem portion 1 of the artificial joint 11
4 is formed by cutting or the like so as to have a convex portion 15 suitable for joining with the human bone 12 at a temperature above the transformation point.

Next, as shown in Figure 4, below the transformation point, for example at room temperature,
After cooling, the convex portion 15 is plastically deformed to give the entire stem portion 14 a smooth shape.

This gives the stem portion 14 a shape that allows it to be easily inserted into the human bone 12.

The usage of the artificial joint constructed in this way is as follows.

That is, as shown in FIGS. 3 and 4C, the artificial joint 1
After inserting the stem part 14 of 1 into the human bone 12, the stem part 1
4 to the transformation point, the stem portion 14 returns to its original shape as shown in FIG. No problems will occur.

Next, when the present invention is applied to a screw connecting human bones, as shown in FIG. At a humidity below the transformation point, the screw threads 17 are rounded by plastic deformation to form a smooth overall shape as shown by the solid line, and the screw 16 is completed.

When connecting human bones using the screw 16 configured in this manner, the screw 16 is inserted into the human bone.

After insertion, if the screw 16 is heated above its transformation point by high-frequency heating or the like, the screw thread 17 will return to its original shape with a sharp top shown by a chain line, and will be embedded into the human bone to ensure a strong bonding force.

As described above, the connecting device for living bones of the present invention can be easily manufactured using conventional processing techniques such as cutting and plastic working, and when used for connecting living bones, The living bone and the component can be easily and reliably connected without using bone cement that damages living tissues such as human bones due to heat generation, and without leaving stress in the living tissues.

Shape-memory metals, such as 50N i -50T i, have a transformation point of about 40°C, and therefore it is necessary to heat them to this transformation point in order to restore the shape of the member to its original shape. It meets all the requirements for a biomaterial because it does not damage living cells and has excellent corrosion resistance, strength, and biocompatibility.

In addition, it can be widely used in places where living bones are inserted, such as artificial hip joints, artificial knee joints, artificial elbow joints, and bone screws.

As is clear from the above description, according to the present invention, it is possible to obtain a connecting tool that allows easy and reliable connection between a living bone and a member, and does not cause damage to the living bone.

[Brief explanation of drawings]

Fig. 1 is an explanatory longitudinal cross-sectional view showing a conventional artificial joint connection part, Fig. 2 is a longitudinal cross-sectional explanatory view showing a conventional fracture connection part, and Fig. 3 shows an artificial joint connection part according to an embodiment of the present invention. FIG. 4 is an explanatory front view showing a leg portion of the artificial joint, and FIG. 5 is an explanatory front view showing a threaded portion. 11...Artificial joint, 12...Human bone, 1
4... Stem portion, 15... Convex portion, 16
...screw, 17...screw thread.

Claims (1)

[Claims] 1 A connecting tool for connecting a living bone part to another living bone part or other member, which is molded into a shape that can be inserted into the living bone part and has a locking protrusion that protrudes at a temperature above the transformation point. A connecting device for a living bone part, comprising, at least in part, a member formed by plastically working a shape-memory metal into a shape in which the locking protrusion does not protrude at a temperature below the transformation point.