RU2127096C1 - Knee joint endoprosthesis - Google Patents

Abstract

FIELD: medicine; orthopedics; traumatology. SUBSTANCE: knee joint provides for displacement of femoral and tibial components relative to each other with preset trajectory of instantaneous rotary centers of man's healthy knee joint. Endoprosthesis construction includes boss positioned in femoral part of endoprosthesis. Two axles pass through boss. Ends of axles move along four shaped grooves arranged in pairs in walls of body of endoprosthesis femoral part. Boss is coupled loosely to tibial part through bearing. EFFECT: provision for the most favorable modes of operation of knee muscles. 2 dwg

Description

 The invention relates to medicine, namely to traumatology and orthopedics, in particular to knee joint prostheses.

 Knee arthroplasty is known (French patent N 2612767-A1, MKI A 61 F 2/38, priority from 03/23/1987, PCT application N WO 90/04369, priority from 05/05/1990. A. St. USSR N 1580182 A1, MKI A 61 F 2/38, priority from 12/21/1987, German patent N 3431645 A1, MKI A 61 F 2/38, priority from 08/29/84 and others.

 In known knee joint endoprostheses (CC), the instantaneous center of rotation (MCV) is stationary during flexion-extensor movements of the composition.

 It is known that during the flexion-extensor natural movement of a healthy knee composition of a person, the MCV is unstable and moves along a certain trajectory, the shape of which is due to the individual geometry of the supporting surfaces of the knee structure.

 Due to the mismatch between the natural operating modes of the adductors in a healthy knee structure and the operating modes of endoprostheses of known designs, the attachment of the legs of the femoral and tibial parts of the prosthesis is loosened. This necessitates endoprosthetics.

 As the closest analogue of the proposed technical solution, an endoprosthesis claimed by GMT (German patent N 3431645 A1) was selected, consisting of two unrelated components that are arranged to move relative to each other, and at least one element is located between the elements bearing allowing bending of their longitudinal axes.

 The claimed technical solution for the design of the endoprosthesis is aimed at solving the following technical problem: in mass production, ensuring the operating modes of the adductors of the knee joint that are most favorable for the stability of the endoprosthesis and are close to natural biomechanics, by statistical selection of several of the most common trajectories of the MCV and the manufacture of a number of standard sizes of endoprostheses based on these data, and in case of individual manufacture - obtaining an endoprosthesis with a trajectory of the MCV, the difference of which from a specific th path SCW patient will be due solely to errors of measuring instruments, X-rays and metal-working machines. Figure 1 shows the endoprosthesis; in FIG. 2. - section AA in FIG. 1.

 The inventive endoprosthesis of KS consists mainly of two parts, one of which is executed as the femoral part 1, and the other as the tibial part 2. Parts 1 and 2 are attached to the corresponding bones of the KS.

 A bearing 3 is located between the component parts, which is attached to the tibial part 2 by a screw 4. The surface of the bearing 3 corresponds to the surface of the part 1 facing it and allows for the rotational and rotational movements of parts 1 and 2 relative to each other, while in the unbent state the protrusion on the bearing 3 does not allow rotational movements.

 Unlike the closest analogue in the proposed design, the boss 5 is located in the cavity of the femoral part 1. Between the boss 5 and the tibial part 2 there is a bearing 6, which is the joint of parts 1 and 2. Bearing 8 allows rotational and rotational movements of parts 1 and 2 relative to each other friend.

 The boss 5 and the femoral part 1 are movably interconnected by two axles 7, which move along the figured spacers 8 inserted into the grooves of the side walls of the femoral part 1. From the outside, protective plates 9 are inserted into the grooves.

 The specific parameters of the MCV trajectory depend on the location of the axes 7 in the boss 5, the coordinates of the centers and the radii of the grooves in the side walls of the femoral part 1.

 The prosthesis is made of known materials by known methods.

 Complete assembly and sterilization of the endoprosthesis of the COP is carried out outside the operating room by known methods.

 Since the external form, dimensions of the endoprosthesis and the nature of the articulation of the femoral and tibial parts do not differ from the known analogues, the method of setting the proposed endoprosthesis of the CS also has no fundamental differences.

Claims (1)

 An endoprosthesis of the knee joint, consisting of the femoral and tibial parts that are not connected to each other, between which bearings are located, allowing limited rotational and rotational movements of the parts of the prosthesis relative to each other, characterized in that a boss connected to the side is placed in the inner cavity of the tibial part the walls of the femoral part by a system of connecting elements made in the form of two axes passing through the boss and resting at least one end on an arcuate groove in the lateral nke femoral portion through a contoured gasket inserted into the groove, with the movable parts of the prosthesis relative to each other with a predetermined trajectory instantaneous centers of rotation of the prosthesis relative to one another.

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