RU2760081C1 - Device for lowering the femur before endoprosthetics - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention relates to medicine. A device for lowering the femur, containing a pelvic support and a femoral support connected to each other, with the possibility of changing the mutual position, with bone clamps installed on them. The pelvic support is made in the form of a flat arc with holes. The femoral support is made in the form of a detachable flat ring with holes. The supports are connected by three telescopic rods. The distal ends of the telescopic rods are fixed on the femoral support. The proximal ends of the telescopic rods are connected to the pelvic support by means of single-plane axial fixed hinges. Three spokes with a diameter of 2 mm, equipped with thrust pads, and two bone screws with a diameter of 6 mm are fixed on the pelvic support. Three spokes with a diameter of 2 mm, equipped with thrust pads, are mounted with a cross and fixed on the femoral support.EFFECT invention provides the possibility of metered movement of the femur relative to the pelvis, while ensuring a stable mutual position of the pelvic and femoral supports, increasing the reliability of fixing the supports to the iliac and femoral bones and eliminating the risk of migration of the spokes.5 cl, 9 dwg

Description

Technology area

The technical solution relates to medical technology, to devices for external skeletal fixation. It is intended for minimally invasive dosed transposition (bringing down) of the femur in case of violations of the anatomical integrity of the hip joint with pronounced prolonged proximal dislocation of the greater trochanter and rigidity of soft tissues.

State of the art

A device for lowering the femur is known (source [1]: patent RU 169919 U1, published: 06.04.2017). The device contains pelvic and femoral modules. The modules are interconnected with the possibility of changing the relative position. The pelvic module is made of two arcs, left and right, connected to each other in the horizontal plane by telescopic distraction rods. Bone fixators, wires and / or bone screws are attached to each of the arcs. The left arch is intended for attachment to the wing of the left iliac bone, the right arch is for attachment to the wing of the right iliac bone. The femoral module consists of an arc and two rings arranged in series one above the other, connected to each other. Each ring has spokes that are designed to be attached in the distal part of the femur. Intraosseous rods are installed on the arch of the femoral module, which are designed to be attached to the femur in the region of the greater trochanter. The pelvic module is hingedly connected to the femoral module by telescopic distraction rods directed in the distal-lateral direction from the pelvic module to the femoral module. Three telescopic distraction rods are installed, through the hinges, one end on the arch of the femoral module, the other end on the right (left) arch of the pelvic module. The fourth telescopic distraction rod is mounted through the hinges on the ring of the femoral module, with the other end mounted on one of the telescopic distraction rods connecting the arcs of the pelvic module in the horizontal plane. The device provides for the direction of traction forces to increase the offset of the femur and allows the application of traction forces to the femur aimed at its lateralization.

The device [1] contains 12 bone fixators intended for insertion into the bones of the limb, for which the femoral bone is brought down. In the wing of the pelvic bone, 4-5 pins are inserted, or 3 bone screws, such as the Shants screw. Such a number of bone fixators allows the femur to be rigidly fixed, but increases the risk of infection penetrating through soft tissue punctures. In addition, the structure contains 3 supports in the femoral module, 2 supports in the pelvic module, such a number of supports increases the weight of the structure, makes it bulky and inconvenient for the patient, and reduces his mobility. The design is more suitable for use in traumatic injuries of the pelvis and hip; it is inappropriate to use it for congenital dislocation of the hip for lowering. The device [1] reduces the patient's physical activity in the process of lowering the hip and increases the risk of infection.

The known method of one-stage bilateral hip arthroplasty with bilateral dysplastic coxarthrosis with complete dislocation and high displacement of the femoral heads (source [2], patent RU 2397720 Published: 27.08.2010). The source [2] describes an external fixation device, contains two blocks (for the left and right limbs), symmetrically installed on both sides at the level of the hip joints. Each block contains a pelvic support in the form of an arc, to which the spokes are attached, carried out in the wing of the ilium, and a femoral support in the form of a ring, to which the spokes are fixed, carried through the diaphysis of the femur, the supports are connected by threaded distraction rods with the possibility of changing the relative position. The device provides for bringing down both femurs to the physiological level.

The disadvantage of the external fixation device [2] is the inability to change the angular position of the femoral support relative to the pelvic support, since the distraction rods do not contain hinges. This does not allow changing the direction of the traction forces applied to the femur to bring it down. For the treatment of diseases of one hip joint (right or left), for example, such as congenital dislocation of the hip, the design is unnecessarily cumbersome, implies fixation of two hip joints at once, which significantly limits the patient's motor activity and adversely affects the treatment process.

A device for treating injuries and consequences of injuries to the pelvic bones is known (source [3]: patent RU 182009 U1 Published: 31.07.2018). The device contains a static pelvic module, static and dynamic femoral modules. The pelvic module is made of two sectoral arcs connected by a transverse beam. The pelvic module contains two supports, made in the form of half rings, rigidly connected to the sectoral arcs. The half rings contain pins and / or rods of screws designed to be held in the supra-acetabular region of the ilium. The static femoral module is located on the intact side of the pelvis and consists of an arch and a ring connected by rods. The ring has spokes that are designed to be attached in the distal part of the femur. Intraosseous rods are installed on the arch, which are designed to be attached to the femur in the region of the greater trochanter. The dynamic femoral module is located on the damaged side of the pelvis and consists of a ring on which the spokes are installed, intended for attachment in the distal part of the femur. The ring of the dynamic femoral module is connected by four telescopic distraction rods to the sectoral arch of the pelvic module. Telescopic distraction rods are hinged on a sectoral arc. The static and dynamic femoral modules are interconnected by hinged beams.

The structure [3] contains 2 supports in the femoral module, 2 supports in the pelvic module, and a plurality of connecting rods. Such a number of supports and rods increases the weight of the structure, makes it cumbersome and inconvenient for the patient, and reduces his mobility. The device [3] reduces the patient's physical activity in the process of lowering the hip and increases the risk of infection. The device is difficult to install, the joining of many parts increases the duration of the operation and reduces the efficiency of the operating room.

Known apparatus for the treatment of congenital dislocation of the hip in children (source [4]: Patent RU 54305, published: 27.06.2006). The device contains a pelvic support and a femoral support, interconnected by means of telescopic rods with ball (spherical) hinges at the ends. The supports are connected with the possibility of changing the relative position in a wide range of directions. Each of the telescopic rods includes rods installed on both sides of the tube with the possibility of bolting and connected to the ball elements of the hinges by means of nuts. The pelvic support contains fixation elements in the form of spokes with thrust pads, fixed on it by means of clamps, and is made in the form of an arc with protruding pads located at an angle to the plane of the arc. The platforms are equipped with a socket with a ball element installed in it and contain a bolt lock. The femoral support contains fixation elements in the form of spokes with clamps and is made in the form of an arc with protruding platforms located in the plane of the arc. The femoral support is equipped with ball elements installed in it similarly to the pelvic support.

The disadvantage of the design [4] is the use of spherical hinges, they do not provide reliable fixation of the femur in a given position during bringing down, since due to significant efforts arising from resisting releasing soft tissues, muscles, the ball joint can be broken and the relative position of the pelvic and femoral support. The multidirectionality of the telescopic assemblies connecting the arches of the apparatus prevents directional, dosed lowering of the head. To bring the femur down, it is not required to use the entire range of mutual angular displacements of the supports that the device allows. Each of the telescopic rods contains two hinges, which reduces the reliability of fixing the mutual position of the pelvic and femoral supports. In addition, with reduced bone density and the resulting efforts during bringing down, it is possible for the spokes to cut through the bone tissue of both the pelvic and the femur. The possibility of eliminating the migration of wires during distraction is not provided. The pins in the iliac wing area do not fix the device well enough, they can cut through the bone and soft tissues, causing an inflammatory process, in the worst case, a part of the iliac wing may also break off or detach. Also, the hinges are structurally removed from the support plane, which increases the overall dimensions of the apparatus.

The essence of the technical solution.

The technical problem to be solved by the technical solution is to ensure the possibility of lowering the thigh in a given direction relative to the pelvis, in combination with the possibility of eliminating the migration of the spokes and ensuring the stable position of the supports, without increasing the number of soft tissue punctures, and an easy-to-use structure.

The technical result consists in providing the possibility of dosed movement of the femur relative to the pelvis, while ensuring a stable mutual position of the pelvic and femoral supports, increasing the reliability of fixing the supports to the ilium and femur and eliminating the risk of migration of the spokes.

The technical result is achieved in that the device for lowering the femur contains interconnected with the possibility of changing the relative position of the pelvic support and the femoral support with mounted on them bone clamps. The pelvic support is made in the form of a flat arc with holes, the femoral support is made in the form of a split flat ring with holes, the supports are connected by three telescopic rods, the distal ends of the telescopic rods are fixed on the femoral support, the proximal ends of the telescopic rods are connected to the pelvic support by means of single-plane axial fixed hinges, on the pelvic support there are three pins with a diameter of 2 mm, equipped with thrust pads, and two bone screws with a diameter of 6 mm, on the femoral support are installed with a cross and three pins with a diameter of 2 mm, equipped with thrust pads, are fixed.

It is envisaged that the bone screws are made with a through channel intended for the passage of the spoke, a slot intended for the location of the bent end of the spoke, a nut is installed on the threaded end.

It is envisaged that the bone screws are mounted on the spokes, fixed on the support, and the bone screw is mounted on the bracket with the possibility of dosed longitudinal movement by means of nuts.

It is envisaged that the diameter of the femoral support is less than the diameter of the pelvic support.

It is envisaged that the single-plane axial fixed hinges are made in the form of two brackets tightened by a bolt with a nut, and the axes of the bolts of all three hinges are parallel to each other.

The technical solution is illustrated by graphic materials:

FIG. 1 - photograph, general view of the device model;

FIG. 2 is a photograph, a view of the pelvic support of the device, wires and bone screws are installed together;

FIG. 3 is a diagram, front view, the device is mounted on the ilium and femur;

FIG. 4 is a diagram, side view, the device is mounted on the ilium and femur;

FIG. 5 - diagram, general view of the device;

FIG. 6 is a schematic, general view, the device is mounted on the ilium and femur, bone screws with channels are installed on the spoke, to eliminate migration and ensure rigidity of fixation, while reducing the risk of infection;

FIG. 7 is a diagram, general view, a device with bone screws with channels mounted on the needles, on the pelvic and femoral supports;

FIG. 8 is a diagram, general view, a device with bone screws with channels mounted on the needles, on the pelvic and femoral supports;

FIG. 9 is a diagram, general view of the pelvic support, with bone screws with channels mounted on the needles.

Specification:

1 - pelvic support;

2 - femoral support;

3 - spoke;

4 - persistent platform;

5 - bone screw;

6 - fasteners;

7 - telescopic bar;

8 - holes;

9 - half ring;

10 - bolt;

11 - nut;

12 - distraction nut;

13 - one-plane axial fixed hinge;

14 - channel;

15 - slot;

16 - bent end of the spoke;

17 - nut;

18 - bracket;

19 - nut;

20 - bar;

21 - bracket;

22 - bolt;

23 - nut.

Implementation of the technical solution.

Example 1 (Fig. 1; 2). The device for lowering the femur contains a pelvic support 1 and a femoral support 2 with bone clamps installed on them, made in the form of spokes 3 with a diameter of 2 mm, with thrust pads 4 and bone screws 5 with a body diameter of 6 mm. On the pelvic support 1, three wires 3 and two bone screws 5 are fixed, on the femoral support 2, three wires are installed with a cross and three wires are fixed. 2 and 3 to the bones. Spoke 3 and bone screws 5 are fixed on supports 2 and 3 with fasteners 6. Pelvic support 1 and femoral support 2 are interconnected with the possibility of changing the relative position by means of three telescopic rods 7. The pelvic support 1 is made in the form of a flat arc with holes 8. Femoral support 2 is made in the form of a split flat ring with holes 8, consisting of two half-rings 9 connected by bolts 10 with nuts 11. Telescopically, the rods 7 contain distraction nuts 12 designed to change the length of the rods 7. The distal ends of the telescopic rods 7 are fixed on the femoral support 2 by nuts 11. The proximal ends of the telescopic rods 7 are connected to the pelvic support 1 by means of one-plane axial fixed hinges 13.

Example 2 (Fig. 3; 4; 5). The device for lowering the femur contains a pelvic support 1 and a femoral support 2 with bone clamps installed on them, made in the form of spokes 3 with a diameter of 2 mm, with thrust pads 4 and bone screws 5 with a body diameter of 6 mm. On the pelvic support 1, three pins 3 and two bone screws 5 are fixed, on the femoral support 2 they are installed with a cross and three pins 3 are fixed.

The diameters of the wires 3 and bone screws 5 and a given number of wires 3 and bone screws 5 provide the necessary and sufficient rigidity of fixing the supports 2 and 3 to the bones. Spoke 3 and bone screws 5 are fixed on supports 2 and 3 with fasteners 6. Pelvic support 1 and femoral support 2 are interconnected with the possibility of changing the relative position by means of three telescopic rods 7. The pelvic support 1 is made in the form of a flat arc with holes 8. Femoral support 2 is made in the form of a split flat ring with holes 8, consisting of two half-rings 9 connected by bolts 10 with nuts 11. Telescopically, the rods 7 contain distraction nuts 12 designed to change the length of the rods 7. The distal ends of the telescopic rods 7 are fixed on the femoral support 2 by nuts 11. The proximal ends of the telescopic rods 7 are connected to the pelvic support 1 by means of one-plane axial fixed hinges 13. One-plane axial fixed hinges 13 are made in the form of two brackets 21 tightened by a bolt 22 with a nut 23, and the longitudinal axes of the bolts 22 of all three hinges 13 are parallel to each other ...

Example 3 (Fig. 6; 7; 8; 9). The device for lowering the femur contains a pelvic support 1 and a femoral support 2 with bone clamps installed on them, made in the form of spokes 3 with a diameter of 2 mm, with thrust pads 4 and bone screws 5 with a body diameter of 6 mm, a screw thread 20 mm long. On the pelvic support 1, three pins 3 and two bone screws 5 are fixed, on the femoral support 2 they are installed with a cross and three pins 3 are fixed, on one spoke 3 of the femoral support 2 there is a bone screw 5. Bone screws 5 are made with a through axial channel 14, designed for the passage of the spoke 3 and the slot 15, intended for the location of the bent end 16 of the spoke 3. At the threaded end of the bone screw 5 there is a nut 17, for pressing the bent end 16 of the spoke 3. Bone screws 5 are installed on the needles 3, fixed on the support 1 and 2, moreover, the bone screw 5 is mounted on the bracket 18 with the possibility of dosed longitudinal movement by means of the nuts 19. The diameters of the spokes 3 and bone screws 5 and a predetermined number of spokes 3 and bone screws 5 provide the necessary and sufficient rigidity of fixing the supports 2 and 3 to the bones. Spoke 3 and bone screws 5 are fixed on supports 2 and 3 with fasteners 6. Pelvic support 1 and femoral support 2 are interconnected with the possibility of changing the relative position by means of three telescopic rods 7. The pelvic support 1 is made in the form of a flat arc with holes 8. Femoral support 2 is made in the form of a split flat ring with holes 8, consisting of two half-rings 9 connected by bolts 10 with nuts 11. Telescopically, the rods 7 contain distraction nuts 12 designed to change the length of the rods 7. The distal ends of the telescopic rods 7 are fixed on the femoral support 2 by nuts 11. The proximal ends of the telescopic rods 7 are connected to the pelvic support 1 by means of single-plane axial fixed hinges 13. The diameter of the femoral support 2 is less than the diameter of the pelvic support 1 and the distal ends of the telescopic rods 7 are installed by means of slats 20. The one-plane axial fixed hinges 13 are made in the form of two brackets 21 tightened by bolt 2 2 with a nut 23, the longitudinal axes of the bolts 22 of all three hinges 13 being parallel to each other. Telescopic rods 7 are parallel to each other. The parallelism of the installation of the bolts 22 of the hinges 13 and the rods 7 allows, if necessary, to change the angle between the supports 1 and 2, and, consequently, to change the direction of traction.

Using a technical solution.

A device for lowering the femur is used for transposition of the femur in two-stage hip arthroplasty. On the operating table, the patient is laid on its side. I mount the pelvic support 1 on the ilium. After processing the operating field, three wires 3 with solders 4 are carried out in the direction through the upper anterior part of the iliac wing, the spine, into the posterior part of the iliac wing. The free ends of the spokes 3 are fixed with fasteners 6 to the pelvic support 1 using holes 8. Mount the femur support 2 on the femur. Three crossing needles 3 with solders 4 are passed through the lower third of the femur, the free ends are fixed with fasteners in the femoral support 2 using holes 8. The pelvic support 1 and the femoral pore 2 are connected with telescopic rods 7 with hinges 13. From the second day after the operation, lowering begins. of the femur by distraction of 1-2 mm per day, for this distraction nuts 12 are tightened. When dosed downward, a soft tissue regenerate is formed in the area of the femur along the path of distraction. Telescopic rods 7 with hinges 13, where the axes of the bolts 22 are installed in parallel, provide the possibility of dosed movement of the femur relative to the pelvis. The hinges 13 are located only at the pelvic support 1 and are uniaxial, which allows them to be rigidly fixed while changing the angular position of the supports if necessary. In the process of bringing down, the state of the spokes 3 is monitored, when migration of the spokes 3 occurs, the eruption of the bone and / or soft tissues, two bone screws 5 are driven into the anterior part of the ilium. For example 1: the first bone screw 5 is carried out along the sagittal plane into the anterior iliac spine, the second bone screw is carried out parallel to the first. The free ends of the bone screws 5 are fixed with fasteners 6 to the pelvic support 1 using holes 8. For examples 2 and 3: the end of the migrating wire 3 from the side of the free from the stop pad 4 is released, the bone screw 5 is pushed onto the wire, screwing its end with a screw thread into the bone, the free end of the bone screw 5 is fixed, the wire 3 is pulled and its end 16 is bent into the slot 15, pressing with the nut 17. Bone screws 5 are similarly set on the next wire 3 of the pelvic support 1 and the wire 3 of the femoral support 2. The bone is clamped between the bone screw 5, and the stop pad 4 of the spokes 3, rigidly fixing the device to the bone, excluding the migration of the spokes. This design reduces the risk of infection, since no additional punctures or soft tissue incisions are formed to install bone screws and increase the rigidity of fixation. The design of the device contains only two supports, which allows to reduce weight and reduce dimensions. In addition, the diameter of the femoral support 2 (smaller than the pelvic support 1) also allows the patient to be comfortable and increases his mobility. After reaching the normal (required for the installation of the prosthesis) level of the position of the femur relative to the acetabulum, the device is removed. Endoprosthetics of the hip joint is performed as follows: an anterior-lateral access to the hip joint is performed, the tendons of the gluteus maximus and medius are resected from the greater trochanter, after arthrotomy, the head of the femur is removed into the wound and resected. The acetabulum is treated with cutters and the endoprosthesis cup is installed. For high dislocations and underdeveloped depressions, small cups 44, 46, 48 are installed. With shallow wide dysplastic depressions, cups of size 50, 52, 54, 56 are installed. In case of underdevelopment of the cavity, the roof of the cavity is created by installing an autograft formed from the head of the femur, which is fixed with two intraosseous screws. The leg of the femoral component of the endoprosthesis is driven into the medullary canal of the femur. The head of the femur (the head of the femoral component) is reduced by traction along the axis of the limb and rotation into the cup. After controlling the range of motion in the hip joint, a joint capsule is formed from the soft tissue regenerate formed during distraction of the femur. Control hemostasis is performed and the wounds are sutured, leaving for 48-72 hours with 1-2 installation of drainage.

The use of the device makes it possible to improve the efficiency of total hip arthroplasty in patients with dysplastic coxarthrosis, as it eliminates complications in the form of wire migration and reduces the risk of infection at the preparatory stage, when the femur is brought down. In addition, the device is easily carried by the patient, in contrast to its bulky counterparts, and is simple and convenient for mounting and dismounting.

The number of bone fixators and their diameters are sufficient to withstand the reaction forces arising during descent from rigid soft tissues, tendons, muscles and allow achieving stable and reliable traction without any complications, and if there are disadvantages in the form of tissue eruption, then they are easy eliminated by installing additional bone screws 5 directly on the pins 3 without the need to re-wire the pins 3 and perform "extra" punctures of soft tissues.

Industrial applicability - the device can be manufactured on modern industrial equipment and can be used for its intended purpose in clinical departments specializing in the treatment of orthopedic diseases using external fixation devices.

Claims (5)

1. A device for lowering the femur before endoprosthetics, containing interconnected, with the possibility of changing the relative position, pelvic support and femoral support, with bone clamps installed on them, characterized in that the pelvic support is made in the form of a flat arc with holes, femoral support made in the form of a split flat ring with holes, the supports are connected by three telescopic rods, the distal ends of the telescopic rods are fixed on the femoral support, the proximal ends of the telescopic rods are connected to the pelvic support by means of single-plane axial fixed hinges, on the pelvic support there are three spokes with a diameter of 2 mm, equipped with thrust pads, and two bone screws with a diameter of 6 mm, on the femoral support are installed with a cross and three wires with a diameter of 2 mm, equipped with stop pads, are fixed. 2. The device for bringing down the femur according to claim 1, characterized in that the bone screws are made with a through channel intended for the passage of the spoke, a slot designed to locate the bent end of the spoke, a nut is installed on the threaded end of the bone screw. 3. The device for bringing down the femur according to claim 2, characterized in that the bone screws are mounted on the spokes, fixed on the support, and the bone screw is mounted on the bracket with the possibility of dosed longitudinal movement by means of nuts. 4. The device for bringing down the femur according to claim 1, characterized in that the diameter of the femoral support is less than the diameter of the pelvic support. 5. The device for lowering the femur according to claim 1, characterized in that the one-plane axial fixed hinges are made in the form of two brackets tightened by a bolt with a nut, and the axes of the bolts of all three hinges are parallel to each other.

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