RU2326624C1 - Femoral endoprosthesis - Google Patents

Abstract

FIELD: medicine; traumotology.

SUBSTANCE: endoprothesis comprises head, shaft, spherical body, foot and shaft barrel. Spherical body is mounted in trochanteric part of foot. Specified barrel is furnished with thread on inner surface and wrench hexagonal socket in lower part. Inner surface of specified hexagonal socket is furnished with spherical recess to hold spherical body below equator. Head is integrated with shaft. Shaft is cylindrical, and in subcapital part it is wrench hexagonal, in centre it is threaded to provide screwed connection to thread of specified barrel, in end face it is furnished with spherical recess congruous to spherical body.

EFFECT: provides improved hip joint endoprosthesis replacement results owing to smooth correction of "АТ", "РТ" and "ШДУ".

3 dwg

Description

The device relates to the field of medical technology. It is used in traumatology orthopedics in cases where pathological changes in the hip joint require its replacement.

Known designs for endoprostheses of the hip joint, allowing, if necessary, change the deviation of the neck: antitorsia (AT), retrotorsia (RT) and cervical-diaphyseal angle (SDU). However, they allow correction of the gear (i.e. only discretely) and by insignificant angles. Endoprostheses are proposed, the designs of which allow the possibility of smooth correction of neck deviation, moreover, by slightly larger values. This was made possible through the use of ball joints [1, 2]. However, these designs do not always provide the ability to make the necessary correction.

The closest, in its technical solution, is an endoprosthesis of the proximal femur [3]. The head of this endoprosthesis through the neck is connected with a spherical body mounted with the possibility of rotation and fixation in a spherical hole of the trochanteric section. The presence of a ball joint allows for the correction of all types of neck deviations. However, the correction amplitude in this device is also limited by a conical hole through which the neck passes connecting the head with a spherical body.

The invention consists in a combination of features sufficient to achieve the desired technical result, i.e. improving the outcomes of hip joint replacement, due to the possibility of smooth correction of AT, RT and SJD, and the amplitude of neck deviations in it is significantly increased in comparison with the known analogues.

This essence consists in the fact that the hip joint implant contains a head, a neck connected with a spherical body placed with the possibility of rotation and fixation in the cavity of the reciprocal form, as well as a leg and wrenches. The head is made as a unit with a cylindrical neck, the subcapital part of which has a hexagonal shape. The middle part of the neck is threaded and interacts with the thread on the inner surface of the cylindrical body of the neck. At the end of the neck there is a spherical recess congruent to the spherical body fixed in the trochanteric part of the leg, the neck body in the lower part has a hexagonal bulge, on the inner surface of which there is a spherical recess covering the spherical body below its equator. The device kit includes two simple open-end single-ended wrenches, one of which, straight, is designed for hexagonal thickening of the leg body, and the other for the subcapital hexagonal section of the neck and has a bayonet-shaped handle.

The presence of a spherical recess in the end of the neck and a similar recess on the inner surface of the thickened lower part of the neck body, covering the spherical body below its equator, provides reliable fixation of the spherical body in the working position of the device.

Placing a spherical body in the trochanteric part of the leg increases the area of its free surface not in contact with the spherical cavity, which provides an increase in the amplitudes of all types of neck deviations.

The presence of a hexagonal subcapital section of the neck, as well as a hexagonal thickening in the lower part of the neck body, provide the possibility of reliable fixation of the spherical body in a spherical recess while maintaining the established deviation of the neck with wrenches.

The presence of a bayonet-shaped bend of a wrench handle, designed for the subcapital hexagonal portion of the neck, makes it possible to use it after the head is inserted into the cavity.

Figure 1 shows a General view of the device, figure 2 is a cross-section, figure 3 shows a wrench for subcapital hexagonal section of the neck.

The head 1 is made integrally with a cylindrical neck 2, the subcapital part 3 of which has a hexagonal shape, the middle part 4 of the neck 2 is threaded and interacts with the thread on the inner surface of the cylindrical body 5 of the neck 2. At the end of the neck 2 there is a spherical recess 6 congruent to a spherical body 7. The housing 5 in the lower part has a hexagonal bulge 8, on the inner surface of which a spherical recess 9 is made, covering the spherical body 7 below its equator. The spherical body 7 is fixed in the trochanteric part of the leg 10. The device comes with two simple one-sided open-end wrenches, one of which is for the hexagonal thickening 8 of the body 5, and the other 11 with a bayonet-shaped handle for the subcapital hexagonal section 3 of the neck 2.

An endoprosthesis of the hip joint is used as follows. One of the common surgical approaches, excising the scar-modified capsule and paraarticular tissue, penetrates the hip joint. If deformative-destructive changes in the cavity are detected, it is replaced with a prosthesis with parameters corresponding to the head 1. The bone-marrow canal of the diaphysis of the thigh is treated correspondingly to the leg 10 and introduced into the prepared bed, fixing there using one of the known methods. Holding the hexagonal thickening 8 of the body 5 of the neck 2 with a straight wrench, use the wrench 11 to rotate the subcapital section of the neck 2. At the same time, the contact between the spherical body 7 and the spherical recess 6 of the end of the neck 2 is broken. Holding the thickening 8 with a straight wrench, after installing the necessary SDU, AT ( or PT), the key 11 rotates the subcapital part 3 of the neck 2 in the opposite direction, which again creates tight contact between the spherical recess 6 of the end of the neck 2 and the spherical body 7. After the head 1 has been inserted into the cavity, the wound is sutured in layers.

The bayonet-shaped bend of the handle of the wrench 11 allows for additional correction of neck deviations in the depth of the surgical wound and after the head has been repositioned (before the wound is sutured).

INFORMATION SOURCES

1. RF patent No. 2213540, M. cl. A61F 2/32, Bull. No. 28, 2003.

2. RF patent No. 2213542, M. cl. A61F 2/32, Bull. No. 28, 2003.

3. RF patent No. 2203637, M. cl. A61F 2/32, Bull. No. 13, 2003.

Claims (1)

An endoprosthesis of the hip joint containing a head, neck, spherical body and leg, characterized in that it has a cylindrical body of the neck, the spherical body is fixed in the trochanteric part of the leg, said body is threaded on the inner surface, and in the lower part with a hexagonal thickening for a nut key, while on the inner surface of the aforementioned hexagonal thickening a spherical recess is made for gripping a spherical body below the equator, the head is made as a unit with the neck, the last olnena cylindrical subcapital in parts - for hexagon wrench in the middle part - threaded for interaction with the thread of said housing, and in the end - with a spherical recess congruent spherical body.

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