RU2564967C1 - Fixing device for greater trochanter of hip bone - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: fixing device for greater trochanter of hip bone contains diaphyseal part with diverging holes for possibility of passing screws in intracortical way and fixing unit, which contains contour bend and two-pronged fork. On-bone part of prongs of the latter has arch-like bend with shape making it possible to bend around trochanter top. Submerged parts of prongs are parallel to each other and are oriented at angle 160-170° relative to diaphyseal part of plate. Length of submerged part of prongs is larger or equals thickness of greater trochanter fragment. A line of angle-stable holes for angle-stable screws, oriented perpendicular to bone axis, is located at prong base.

EFFECT: increased reliability of inter-fragment fixation in case of greater trochanter fracture both after osteotomy by Paavilainen and in case of traumatic fractures and false joints of greater trochanter of hip bone.

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Description

The invention relates to medical equipment, namely to traumatology and orthopedics, and is used for internal fixation of the greater trochanter of the femur during hip joint replacement using osteotomy of the trochanteric paratrochanter according to T. Paavilainen, for false joints of the trochanteric arteries that developed after such osteotomies, as well as osteosynthesis of any fractures and false joints of the greater trochanter, including with corrective osteotomy for post-traumatic deformities.

In patients with high hip dislocation, endoprosthetics use a shortened osteotomy of the femur developed by T. Paavilainen et al. In which temporary excision of the greater trochanter is an element of access to the hip joint (1-2). At the same time, the reliability of fixation of the greater trochanter is one of the key factors ensuring the muscle balance of the joint and the stability of the endoprosthesis in both the early and late postoperative periods. Fractures of the greater trochanter of the femur are characterized by properties that impede osteosynthesis, namely: a short spongy fragment, not always sufficient tissue strength, a small area of inter-fragment contact, frequent background osteoporosis and a very large gluteal muscle applied to the trochanter. This force, with active movements of the lower limb, is directed to the detachment of a fragment of the trochanter from the femur and can lead to damage to the fixators, in which there is mobility that contributes to the development of the false joint, the frequency of which currently reaches 15% (3).

The classical method and device for fixation of the greater trochanter, proposed by T. Paavilainen (2), is the use of wire cerclage, supplemented by screws guided to bypass the endoprosthesis leg. The method is convenient, and devices (cerclage and screws) are just the legs of an endoprosthesis. The method is convenient, and the devices (cerclage and screws) are simple and understandable. The disadvantage of this fixation is that the device, consisting of cerclage and screws, does not adequately withstand the pull of the gluteal muscles, the powerful effect of which on the trochanter often leads to slipping of the wire, breaking of the screws or fragmentation of the trochanter, which leads to its mobility during rehabilitation of the patient in the postoperative period, the development of the pseudoarthrosis and requires its subsequent operational fixation by more powerful devices.

A device is known in the form of a lining with two teeth and fixing them with a “cable” (a special cerclage made of twisted metal rope pulled by a special tensioner and fixed in riveted position) (4). The teeth embedded in the top of the skewer increase the strength of the metal seal in the oblique fragment, and the use of special tools increases the tension force of the “cables”.

The disadvantage of this device is that an increase in cable tension leads to a tendency to cerclage eruption of the bone due to its atrophy from pressure such that even carrying out the “cables” in different planes does not prevent the displacement (slipping) of the large trochanter together with the structure under the influence of the powerful traction of rotators with active rehabilitation of the patient. Moreover, the development of a false joint, which requires rheostosynthesis, is also often noted (4).

Closest to the claimed are the device "Plate for osteosynthesis of fractures of the endoprosthetics bone" (5) and "Device for the restoration of the thigh" (Apparatus and method for repairing the femur) (6). In the first, the channels for the screws are made diverging tangentially for introducing the screws along the chord in a compact layer of bone around the leg of the endoprosthesis. The disadvantage of this device is the lack of elements for fixing the actual skewer. In the second device, for fixing a short epiphyseal fragment of a large trochanter, a curved element with teeth in the form of claws embedded in a large trochanter and a plate is used, which is fixed to the diaphysis with screws and cable (6).

The main disadvantages of this device are the insufficiently deep immersion of the screws in the metaphysis of the thigh (monocortical), their insufficient number, as well as the tendency to erupt and slip of the cage cage, inherited from the previous device, which together lead to frequent loss of fixation when the patient is activated.

The technical result of the present invention is to increase the reliability of inter-fragment fixation in fractures of the greater trochanter as after osteotomy according to Paavilainen, and in traumatic fractures and false joints of the greater trochanter of the femur.

The result of the invention is achieved in that the device comprises a diaphyseal part with holes diverging to allow screws to be inserted intracortically around the endoprosthesis legs, and a fixing unit containing a contour bend and a double-toothed fork, the osseous part of the teeth of the latter has an arcuate bend in shape that allows you to bend around the top of the trochanter, and the immersed parts of the teeth are parallel to each other and oriented at an angle of 160 ° -170 ° relative to the diaphyseal part of the plate, and the length of the immersed part of the teeth is greater than or equal to the thickness of the fragment of the greater trochanter, and at the base of the teeth is a row of holes uglostabilnyh uglostabilnye screws oriented perpendicular to the bone axis.

The illustrations show:

Figure 1. Fork plate for internal fixation of the greater trochanter of the femur (top view), where: 1 - diaphyseal part; 2 - diverging holes; 5 - contour bending; 6 - tooth; 7 - the osseous part of the tooth with a fan-shaped divergence; 9 - immersed parts of the teeth; 11 - angle-stable hole; 12 - angle-stable screw.

Figure 2. The same side view, where 1 is the diaphyseal part; 2 - diverging holes; 5 - contour bending; 6 - tooth; 9 - immersed parts of the teeth; 11 - angle-stable hole; 12 - angle-stable screw. Shows the angle of inclination of the immersed part of the tooth 9.

Figure 3. The same, rear view. 1 - diaphyseal part; 2 - diverging holes; 5-contour bend; 9 - immersed parts of the teeth; 12 - angle-stable screw; 15 - cortical screws, 16 - axis of deflection of the screw 15; 17 - perpendicular to the plane of the diaphyseal part 1 of the plate.

Figure 4. General view of the device on the bone containing the leg of the implant (installation diagram), where 3 is a large trochanter; 4 - the femur, 8 - the top of the greater trochanter (point of introduction of the tooth); 9 - immersed part of the tooth; 12 - angle stable screws; 13 - adjacent cortical layer; 14 - proximal femur; 18 - leg of the endoprosthesis. It is shown that the leg of the endoprosthesis is bypassed by cortical screws 15, the location in the great trochanter of the immersed part of the teeth 9 and the “stitching” of the trochanter 3 and the adjacent cortical plate 13 of the proximal femur (metaphysis) of the femur with angle-stable screws.

The device (Figs. 1-4) consists of a diaphyseal part 1 with diverging openings 2 and in a part corresponding to a large trochanter 3 of the femur 4, and a fixing unit that contains a contour bend 5 with two teeth 6 extending from it, the bone parts 7 of which fan-like diverge and bend along the contour of the top 8 of the trochanter 3. The immersed parts 9 of the teeth 6 are parallel and oriented at an angle of 160 ° -170 ° to the plane 10 of the diaphyseal part 1 (Figure 2). At the base of the teeth 6 along the contour bend 5 there is a series of angle-stable holes 11 for angle-stable screws 12, oriented perpendicular to the surface of the femur 4 (Figs. 2, 3, 4), with the possibility of introducing a screw 12 through a fragment of the greater trochanter 3 and the adjacent cortical layer 13 of the proximal department (metaphysis) of the femur 14. The channels of the diverging holes 2 in the diaphysis part 1 of the device are configured to deflect the axis 16 of the cortical screws 15 in the horizontal plane from the perpendicular 17 by 20 ° -30 ° (Figure 3) for the introduction their bypass prosthesis stem 18 (Figure 4).

The device is used as follows. After surgical access and mobilization of the major trochanter 3 and matching it 3 with the adjacent cortical layer 13 of the femur 4, the device is placed on the bone 3-4, orienting the ends of the immersed part 9 of the teeth to the top 8 of the major trochanter 3. By hammering through the impactor directed along the immersed parts of 9 teeth, hammer the last 9 until they fit snugly into large trochanter 3, i.e. until the lower surface of the contour bend 5 comes into contact with the surface of the greater trochanter 3. After that, the entire device with the large trochanter 3 impaled on the teeth 9 is fixed to the diaphysis by introducing cortical screws 15 through diverging holes 2 in the bone part 1 according to the rules developed for the periprosthetic plate: bypassing the legs of the endoprosthesis 18 and, if possible, the chord inside the compact layer of the femur 4. Complete the metal osteosynthesis by introducing angle-stable screws 12 into the holes 11, passing through the screw 12 through the large trochanter 3 with immersion the tops of the angle-stable screw 12 into the adjacent compact layer of the femur 4. If the patient has the legs of the endoprosthesis cemented, the tip of the screw can be immersed in the cement mantle without direct contact of the screw 12 with the leg 18.

Upon achieving stable internal fixation, the wound is sutured with active drainage. Immobilization in the postoperative period is not applied. The reliability of the fork fixation of a fragment of the greater trochanter of the femur is sufficient for active movements, which, in the absence of ligament injury, begin before the removal of sutures.

The device allows you to:

- to provide increased reliability of inter-fragment fixation of a fragment of the greater trochanter to the metaphysis of the femur;

- to provide the effect of volumetric elastic compression due to the elastic deformation of the contour bending when tightening the cortical screws;

- Reliably withstand the pull of the gluteal muscles. directed along the axis of the thigh. due to the forked fixing unit;

- reliably withstand the thrust of the gluteal muscles, aimed back at the sliding of the skewer fragment from the surface of the femur due to the through fixation of the skewer fragment to the underlying compact layer of the femur;

- allows you to do without special expensive installation tools and without cerclage systems that adversely affect blood circulation in the bone and do not prevent the fragment from slipping in the transverse direction.

Bibliography:

1. Crowe J, Mani V, Ranawat C. Total hip replacement in congenital dislocation and dysplasia of the hip. J Bone Joint Surg. 1979; 61A: p. 15-23.

2. Paavilainen T., Hoikka V., Paavolainen P. Cementless total hip arthroplasty for congenitally dislocated or dysplastic hips. Clin Orthop Relat Res. 1993; 297: p. 71-81.

3. The Adult Hip. The 2nd Edition. Editors: Callaghan, John J .; Rosenberg, Aaron G. .; Rubash, Harry E. 2007 .-- Lippincott Williams & Wilkins. pp. 1569.

4. Guidelines for hip replacement. Edited by: R.M. Tikhilova, V.M. Shapovalova. St. Petersburg, 2008, 324 p.

5. Voronkevich I. A., Mamontov V. D., Malygin R. V. Plate for osteosynthesis of endoprosthetic bone fractures. Patent No. 2261681, priority of 08.19.03.

6. Apparatus and method for repairing the femur. Patent US N 7,207,991 B1. - Baldwin E.A., Kilpela Th.S., Severson B.O. d.p.24.04.2007.

Claims (1)

A retainer for a large trochanter of the femur, containing the diaphyseal part with diverging holes for the possibility of holding screws intracortically and a fixing unit containing a contour bend and a double-toothed fork, characterized in that the osseous part of the teeth of the latter has an arcuate bend in shape that allows you to bend around the top of the trochanter, and immersed parts of the teeth are parallel to each other and oriented at an angle of 160 ° -170 ° relative to the diaphyseal part of the plate, and the length of the immersed part of the teeth is greater than or equal to the thickness o breaking of the greater trochanter, and at the base of the teeth is a row of holes uglostabilnyh uglostabilnye screws oriented perpendicular to the bone axis.

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