JPS62345A - construction knee 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 [Field of Industrial Application] Among joints, the present invention particularly relates to an artificial knee joint that allows rotational movement.

[Conventional technology]

Conventional artificial knee joints have mainly used fulcrum pins to allow a femoral fixation member and a tibia fixation member, which are connected by a pair of hinge mechanisms, to mutually bend and extend.

However, such hinge-type joints do not interfere with the prescribed flexion/extension movements, but in the joint function of the human body, not only simple flexion/extension movements, but also flexion with rotational movement between the femur and tibia. Since extension movements are performed, there is a need for something similar to a natural joint that can perform rotational movements in conjunction with flexion/extension movements. As an artificial knee joint that meets such demands, for example,
98499 and Special Publication No. 58-34138 have already been proposed.

[Problems with conventional technology]

However, in the former case, the entire load is received by the fulcrum pin,
Furthermore, the leg inserted into the metal fitting fixed to the tibia is configured to rotate, and the central axis of the rotational movement of the leg does not coincide with the central axis of the fulcrum pin that performs flexion and extension movement. Therefore, concentrated stress acts on the base of the leg due to the load that is always applied from the center axis of the fulcrum pin to the rotation center axis. There have been several reports of breakage accidents at the base of the legs caused by this. In addition, a rotational moment due to the rotational force acts on the metal fitting that rotatably receives the leg, is inserted into the medullary canal of the tibia, and is fixed with cement, and as a result, the cemented part becomes loose. This has the disadvantage that the supporting part of the artificial joint is damaged.

[Means for solving problems]

In order to solve the above problems, the load is not placed on the fulcrum pin,
The inner cup and the outer cup are configured to receive the load from the femoral bone member by means of a joint member placed on the tibia fixation member, and receive the fulcrum pin on a protrusion arranged on a pedestal on which the joint member is placed. In this way, stress is not applied to the tibia fixation member.

〔Example〕

FIG. 1 shows a broken cross-sectional view of the artificial knee joint according to the present invention as seen from the front, FIG. 2 shows a central cross-sectional view of the same, and FIG. The femoral fixation member 1 and the tibia fixation member 2 are configured to perform bending and extension movements as shown by dotted lines in FIG.

Among these, the tibia fixing member 2 includes a leg part 3 to be inserted into the medullary canal of the tibia, a pedestal 4 on the upper part of the leg part 3, and a spherical or cylindrical protrusion approximately in the center of the pedestal 4. 5 is integrally formed of a metal material. Further, an inner cuff protrusion having a recess 6b for receiving the protrusion 5 and a shaft hole 6a passing through in the lateral direction is attached to the inner cuff so that the protrusion 5 serves as a circumflex axis. Further, an outer cup 7 having a shaft hole 7a, which is a through hole, is attached to the inner cup 6. Further, the joint member 8 is attached so as to cover the outer cup 7 that has received the inner cup 6 therein. In this case, the shaft hole 8a drilled in the protrusion 8b formed in the joint member 8 is connected to the built-in inner cup 6 and outer cup 7.
After the shaft holes 6a and 7a are arranged so as to coaxially communicate with each other, the protrusion 8b of the joint member 8 is inserted into the femur so that its axis coincides with the screw hole 1a drilled in the femoral bone fixing member 1. It is inserted into the oral cavity 1b formed in the fixing member 1. Thereafter, by screwing in the fulcrum pin 9, the artificial knee joint as shown in FIGS. 1 and 2 is constructed.

In the artificial knee joint constructed in this way, as shown by the dotted line in FIG.
The bending and extension movements of the knee in the human body are performed arbitrarily in the range of 0 degrees), and the load is applied by sliding the bottom surface 1c of the femoral bone fixing member 1 on the upper surface of the collar 8c of the joint member 8. Can exercise.

At the same time, the inner cup 6 received via the outer cup 7 into the protrusion 8b of the joint member 8 through which the fulcrum pin 9 is inserted rotates around the protrusion 5 formed on the pedestal 4, thereby fixing the femur. The member 1 and the tibial fixation member 2 can perform a rotational movement relative to each other under an angle θ, which can be up to about 40 degrees.

It is preferable that at least the inner cuff member, the joint member 8, etc. of the above-mentioned joint constituent members be formed of synthetic resin such as high-density polyethylene. The femoral fixation member and the tibia fixation member mutually bend and extend around the pin, and in addition rotate around the protrusion provided on the tibia fixation member, making it more similar to the natural knee joint in the human body. This invention can bring near joint movement to people who have had joint replacements due to rheumatism, bone cancer, disasters, etc.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are a front cutaway view and a central cross-sectional view, respectively, of an artificial knee joint according to the present invention. FIG. 3 is an exploded three-dimensional view of the artificial knee joint according to the present invention. Femoral fixation member 2: Tibial fixation member 4: Rest 5: Protrusion 6: Inner cassette 7: Outer cup 8: Joint member 9: Fulcrum pin

Claims (1)

[Claims] In order for the femoral fixation member fixed to the femur and the tibia fixation member fixed to the tibia to perform relative flexion and extension movements, the tibial fixation member is provided with a pedestal, and an inner part is rotatably attached to a protrusion formed on the upper surface of the pedestal. A cup is attached, an outer cup is mounted so as to surround the inner cup, and a joint member having a protrusion and a brim integrally formed to receive the outer cup is arranged so that the brim thereof is seated on the pedestal. The inner cup, the outer cup, and the protruding part of the joint member with the shaft holes drilled in the joint member aligned are inserted into the concave cavity formed in the femoral bone fixing member, and passed through the screw hole drilled in the femoral bone fixing member. An artificial knee joint made by inserting a fulcrum pin into the shaft hole of a joint member.