JPS622943A - Artifial 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 [Industrial Field of Application] The present invention relates to an artificial knee joint equipped with a hinge mechanism.

[Conventional technology and its problems]

Conventional hinge-type artificial knee joints are, for example,
As seen in Publication No. 34138, the femoral component and tibial component are rotatably connected using a fulcrum pin, and the overall structure is relatively simple. Because the two parts are connected in advance with a fulcrum pin and attached with silk, it is difficult to perform the surgery efficiently when attaching and fixing the femoral component to the femur and the tibial component to the tibia during knee joint replacement surgery. was there.

On the other hand, when the femoral and tibial components are separated, it is easy to attach and fix each component to the femur and tibia, but it is difficult to rotate both components with a fulcrum pin afterwards. It is necessary to connect them freely. So, is it possible to perform surgery as much as possible? In order to complete the process quickly, the fulcrum pin is generally structured so that it can be easily inserted into a predetermined hole.

However, although the fulcrum pin can be easily inserted and connected and fixed, it also has the disadvantage that it can easily come out or fall off. As a result, after replacing a knee joint and inserting it into a living body, there was a risk that the fulcrum pin would come off and the joint function would collapse.

[Failure to solve the problem]

In view of the above circumstances, an annular groove is formed on the inner periphery of the opening of the screw hole of the fulcrum pin so that the fulcrum pin can be easily inserted and fixed and will not come off once connected. It has a mating collar and the end face of the fulcrum pin has a stopper with a blocking protrusion on the inside to fit the opening part described in -I- to prevent the fulcrum pin from being pulled out LJ. shall be.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows
In the front view with the main part of the artificial knee joint cut away, 1 is a femoral bone fixing member, and this femoral bone fixing member 1 has a pair of bifurcated legs 1a, and between these legs 1a, Four portions 1b are formed and pin holes IC are raised.

Further, 2 is a tibia fixing member, -1 partially includes the recess 1b.
A protrusion 2a rotatably inserted therein and a pedestal 2b having an articulating surface on which the distal end surface of the leg 1a makes sliding contact are integrally formed, and a pin hole 2C is bored in the transverse direction. .

2. Femoral fixation part +A' 1 and tibia fixation member 2 are assembled with the protruding part 2a inserted into the fourth part 1b and the pin holes IC12C drilled in each of both fixation members 1.2 aligned. By inserting the fulcrum pin 3 and screwing into the screw groove 3a, the femoral bone fixing member 1 and the tibia fixing part +12 rotate around the fulcrum pin 3 (J). An annular groove 1c1 is formed in an opening adjacent to a pin hole 1c formed in one leg 1al of the bone fixing member 1.
A plug 4 having the shape shown in FIG. 2 is inserted. Zunawaji, this plug 41 has a collar 4a formed on the outer periphery of the end.
A plurality of notches 4h are provided to facilitate deformability of the portion where the . Fig. 3 shows a partially enlarged view of how the plug 4 is inserted and installed. In Fig. 3 (a), the fulcrum pin 3 is tightened in the correct position, but it may be difficult to use it for a long time or tighten it. If the fulcrum pin 3 becomes loose due to insufficient wear, etc.
The end of the fulcrum pin 3 abuts against a protrusion 4c formed inside the stopper 4. Since the collar 4a formed on the outer periphery of the plug 4 engages with the annular groove 1d and cannot escape, the fulcrum pin 3 is blocked by the protruding portion 4C and does not loosen any more. There are no words for LJ. Furthermore, the outer diameter of the fulcrum pin 3 is slightly smaller than the inner diameter of the collar 4a, and if the fulcrum pin 3 becomes loose and moves, the end of the fulcrum pin 3 will enter the inside of the plug 4a, preventing the collar 4a from deforming inward. This prevents the collar 4a from coming off the annular groove 1d, making the engagement action of the collar 4a in the annular groove 1d more reliable.

〔Effect of the invention〕

As described above, according to the present invention, the fulcrum pin that connects the femoral fixation member and the tibia fixation member in a bendable manner has a collar that engages with the annular groove formed in the opening of the pin hole through which the fulcrum pin is inserted. Since the structure is configured by fitting the stopper into the joint, even if the fulcrum pin loosens slightly due to long-term use or insufficient tightening, the joint function is stable and will not continue to loosen. It is possible to provide a highly reliable artificial knee joint that is easy to perform replacement surgery and will greatly contribute to the social welfare of humankind.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of an artificial knee joint according to an embodiment of the present invention, and FIG. 2 is a partially cutaway perspective view of only a plug constituting the =4= artificial knee joint according to the present invention. 3(a) and 3(b) are both enlarged sectional views of a portion of the artificial knee joint according to the present invention. 1: Femoral fixation member 2: Tibial fixation member 3: Fulcrum pin 4; Plug

Claims (1)

[Claims] In a knee joint in which a femoral fixation member fixed to the femur and a tibial fixation member fixed to the tibia move relative to each other in flexion and extension through a hinge mechanism, the inside of the threaded hole opening of the fulcrum pin forming the hinge mechanism is 1. An artificial knee joint, comprising: a plug having an annular groove formed around the periphery, a collar that engages with the annular groove, and a protrusion formed inside the opening, the plug being fitted into the opening.