RU2636902C1 - Distraction device for hip reduction - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: device is a vertically extended cylindrical hollow body hingedly connected to one of its end surfaces, on the distal end side, with a fastening assembly consisting of a horizontally extended area having a rectangular supporting protrusion with a shape and dimensions adapted to the groove of the modular stem body of the hip endoprosthesis, and locking screw through holes located on both sides. Inside the cylindrical hollow body there is a piston dividing its internal cavity into two - an upper and a lower, the latter has a terminal for connection to a hydraulic pump which provides reciprocating movements of the piston along the cylindrical body by introducing liquid into its lower cavity and removing the liquid therefrom, inside the upper cavity in its central part there is a hollow cylinder and a central rod element inside it rigidly secured from the distal end on the piston to provide their protrusion from the end surface of the cylindrical body during movement of the piston in its direction, on the side of the proximal end of the rod element there is a threaded portion formed for connection to a plate mounted on the crest of the ilium.

EFFECT: stability of the installed structure during the implementation of dosed hip reduction, eliminating the risk of its displacement and additional traumatization of bone tissue while maintaining the standard functions of the joint in order to improve the life quality of the patient in the period between two surgical interventions.

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Description

The invention relates to medical equipment used in orthopedics. This technical solution can be used to reduce the proximal part of the thigh to the level of the true acetabulum during a two-stage hip replacement in the treatment of congenital dislocation of the hip.

Residual defects in the development of elements of the hip joint, untimely detection of pathology, and sometimes unqualified treatment lead to the development of dysplastic coxarthrosis in adolescence, accompanied by shortening of the limb, lameness, pain, secondary deformations of adjacent joints and spine, and a violation of their functions. The main method of treating patients with this pathology remains total hip arthroplasty. The greatest difficulty for surgical treatment is represented by patients with a severe degree of dysplasia - a high dislocation of the thigh, requiring the lowering of the thigh when the head is positioned in the cavity. Excessive mobilization of the proximal femur during this manipulation can cause muscle failure in the postoperative period, and severe soft tissue tension is fraught with traction damage to the femoral and sciatic nerves, not to mention the difficulties in repositioning can cause the acetabular component of the endoprosthesis to be displaced. Currently, to eliminate these complications, a two-stage technique for hip joint replacement with intermediate hip reduction using various designs of distraction devices is used.

In most cases, to lower the thigh, distraction apparatuses of external fixation are used, including transosseous elements of the type of spokes or rods [RU patents for inventions No. 2171643, 2406459].

However, when using these devices, which require transosseous transosseous elements, soft tissue can erupt due to tension of the spokes with their subsequent inflammation and instability of the installed device may occur, thereby reducing its repositional capabilities, which, in turn, causes technical difficulties when lowering the thigh distally and may lead to the need for repeated surgical interventions due to remounting of the external structure.

The closest analogue to the claimed invention is Fitbone implantable distraction nail (Wittenstein-intens, Germany), designed to lengthen the lower extremities, but adapted for the treatment of dysplastic coxarthrosis by the method of two-stage total hip arthroplasty with the reduction of the femur to the level of the true acetabulum. The fundamental difference between this device is the transfer of energy necessary for distraction through the skin via a cordless method, using a special device - a power and control unit, i.e. without damaging the skin. The system is configured through a microcomputer, which starts the supply of energy to the electric motor located in the nail. The engine starts at a certain time - day or night, depending on the specified parameters and spreads the bones in very short steps. When using this device during the first surgical intervention, a femoral head is resected, an nail and an endoprosthesis cup are placed intramedullary in an anatomical position with or without acetabular reinforcement. In the postoperative period, they begin to lower the thigh using an established design with a pace of 2-4 mm per day, which is reduced depending on the presence of pain and function. In the second surgical procedure, the distraction nail is removed and the leg of the endoprosthesis is installed.

However, this device is difficult to manufacture due to the presence of electronic elements, as a result of which its cost is also increased. When using this device, the patient should be near the treatment center, where there is a microcomputer with a given lengthening program. With large lengths of movement of the thigh (from the wing to the acetabulum), the gluteal muscles are tensioned, which is accompanied by great resistance to the course of the nail, designed for a total load of up to 20 kg. If this value is exceeded, and in addition, if the patient accidentally steps on a limb, the device may not have enough power and strength to fully carry out the hip reduction, or the motor may breakdown due to burnout. The entire load during distraction falls on transversely inserted locking screws, the diameter of which is not large ≈3.2 mm, which is fraught with their deformation or breakage.

The objective of the invention is to ensure the stability of the installed structure during the metered reduction of the thigh, eliminating the risk of displacement and additional trauma to bone tissue while maintaining standard joint functions in order to improve the quality of life of the patient between two ongoing surgical interventions.

The essence of the claimed invention is characterized in that the distraction device for lowering the dislocation of the hip is a vertically elongated cylindrical hollow body pivotally connected to one of its end surfaces from the side of the distal end, with a mounting unit consisting of a horizontally elongated platform having a rectangular supporting protrusion with the shape and dimensions adapted to the groove of the body of the modular leg of the hip joint prosthesis, and the through holes located on both sides of the hip joint spacer screws, while a piston is located inside the cylindrical hollow body, dividing its internal cavity into two - upper and lower, the latter has an output for connecting to a hydraulic pump that provides reciprocating movements of the piston along the cylindrical body by introducing and removing fluid into its lower cavity, inside the upper cavity in its central part there is a hollow cylinder and a central rod element made inside it, rigidly fixed from the side of the distal end to the pore the screw with ensuring their exit beyond the end surface of the cylindrical body during the movement of the piston in its direction, from the side of the proximal end of the rod element, a threaded section is made for connection with a plate mounted on the iliac crest.

The technical result of the claimed invention.

All distraction devices used to lower the thigh when performing two-stage hip joint arthroplasty, or relate to transosseous devices, the use of which is associated with the occurrence of infectious processes at the points of insertion of their elements - knitting needles, screws, etc .; or to submersible structures adapted for the treatment of this pathology, and therefore their use requires limiting the mobility of the joint. The occurrence of even a minimal load on the submersible device can lead to its displacement, and consequently, to the loss of the achieved results and the need for remounting. In some cases, due to the fact that the design features of these submersible devices were simply not designed for such types of loads, a breakdown of the structure itself can occur, leading to significant trauma to the bone tissue and its additional loss, which complicates the process of installing the hip joint prosthesis in the future . All the technical features developed by the authors of the claimed invention are aimed at eliminating the disadvantages of the above devices, namely, eliminating the risk of infectious complications by immersing the device and ensuring the stability of the installed structure, while simultaneously allowing a minimum number of standard movements in the joint between two surgical interventions, while improving the quality of life of the patient. The stability of the installed structure is ensured by the presence of a protrusion adapted to the shape and size of the groove in the body of the leg of the modular endoprosthesis, and by creating an additional support of the device on the bone tissue with evenly distributed force, excluding overloads, due to the horizontally elongated area of the mounting unit, fixed to the femur with locking screws , excluding the mobility of the entire device, and, therefore, the possibility of its displacement. The connection of the mounting node with a cylindrical body through a hinge allows for normal movement in the joint. The device is easy to manufacture, all its elements can be made on standard technical equipment, without requiring any additional equipment. This can significantly reduce the cost of the claimed design.

Any even minor breakdown of the submersible device requires its re-installation, and therefore, additional surgical intervention. In this regard, the design of devices of this type should be simplified as much as possible. The operation of the inventive device is based on a mechanical principle, simplifying the process of its operation, without requiring a separate specialized specialist and minimizing the possibility of problems associated with the dosage of the hip reduction, for example, due to a malfunction in electronic systems.

The invention is illustrated using the drawing, which schematically shows a distraction device for lowering the thigh. In the drawing, positions 1-11 indicate:

1 - cylindrical hollow body;

2 - horizontally elongated platform mounting hardware;

3 - supporting protrusion of the mounting unit;

4 - through holes of the mounting unit;

5 - the piston;

6 - the upper cavity of the cylindrical hollow body;

7 - the lower cavity of the cylindrical hollow body;

8 - output for connecting to a hydraulic pump;

9 - a hollow cylinder;

10 - core element;

11 - threaded section of the rod element.

The distraction device for lowering the thigh is a vertically elongated cylindrical hollow body 1, pivotally connected to one of its end surfaces, from the side of the distal end, with a mounting unit. The latter consists of a horizontally elongated platform 2 having a rectangular support ledge 3 with a shape and size adapted to the groove of the body of the modular leg of the hip joint prosthesis, and through holes 4 for locking screws located on both sides of it. A piston 5 is located inside the cylindrical hollow body 1, dividing its internal cavity into two - the upper 6 and the lower 7. The lower cavity 7 has a terminal 8 for connection with a hydraulic pump that provides reciprocating movements of the piston 5 along the cylindrical body 1 by introducing and removing fluid into this cavity 7. Inside the upper cavity 6 in its central part there is a hollow cylinder 9 and a central core element 10 made inside it, rigidly fixed from the side of the distal end to the piston 5 to ensure HAND they go beyond the end face of cylinder-body 1 during movement of the piston 5 in its direction. On the proximal end of the rod element 10, a threaded portion 11 is made for connection with a plate mounted on the iliac crest.

A distraction device for lowering the thigh is used as follows.

This device is used in the surgical treatment of congenital high dislocation of the thigh, including a two-stage hip joint replacement. During the first surgical intervention, the patient is placed on a healthy side. They treat the surgical field with antiseptics. Perform surgical access to the hip joint - posterolateral or anterolateral. Mobilize the proximal femur. The head is dislocated and an osteotomy of the femoral neck is produced. Then the head and neck are removed. The femur is displaced anteriorly or posteriorly depending on the access and is taken to the surgical wound. The bone marrow canal of the femur is treated with a scan. The entrance to the medullary canal is formed with a graduated chisel, then with a rasp to the required size of the modular leg of the hip joint prosthesis. Install the modular leg of the hip joint prosthesis. Traction of the femur in the direction of the true acetabulum is performed until the muscles are tensioned and the femur is fixed in the achieved position. A soft tissue incision is made above the iliac wing, a support plate is placed on the iliac crest in the middle of it, and a tunnel is formed in the muscles in the direction of the thigh sawdust. A device with a protrusion size corresponding to the size of the groove in the installed modular leg of the hip joint endoprosthesis is selected. Through the formed tunnel, a distraction device is installed, for which the threaded portion of the rod element is connected to the iliac crest and the protrusion of the fastening assembly into the groove in the body of the monolithic leg of the endoprosthesis, additionally fixing the position of the device by means of locking screws installed through the through holes in the sawdust of the femur . A flexible tube connecting the cylindrical body with a hydraulic pump is brought out through an additional puncture outside the surgical wound, fixing it on the skin. In the postoperative period, hip reduction is performed discretely in time using the installed device, increasing its length by 1-2 mm per day, with a fraction of 4-6 times. To do this, a hydraulic pump is connected to the withdrawn flexible tube, for example, a hydraulic pump through which a liquid - 1% chlorhexedine solution or 0.9% sodium chloride solution is pumped into the lower cavity of the cylindrical body. In this case, under the influence of liquid, the piston moves upward, pushing the inner hollow cylinder with the rod element beyond the cylindrical body from the side of its proximal end, increasing the total length of the device. Upon reaching the reduction of the proximal part of the thigh to the level of the true acetabulum, a second surgical intervention is performed, during which the distraction device is removed and the acetabular component of the hip joint endoprosthesis with the head and neck is installed, assembling the structure together.

Example

The inventive product is made in the form of a number of experimental samples. A model of a hip joint with a high dislocation of the hip was created, on which it was confirmed that the developed improvements of the device justify their constructive expediency.

Claims (1)

A distraction device for lowering the thigh, characterized in that it is a vertically elongated cylindrical hollow body pivotally connected to one of its end surfaces from the side of the distal end, with a mounting unit consisting of a horizontally elongated platform having a rectangular support ledge with a shape and dimensions adapted to the groove of the body of the modular leg of the hip joint prosthesis, and through holes located on both sides of it for locking screws, while inside a cylinder-shaped hollow body is located a piston that divides its internal cavity into two - upper and lower, the latter has an output for connection to a hydraulic pump that provides reciprocating motion of the piston along the cylinder-shaped body by introducing fluid into its lower cavity and removing fluid from it, inside the upper cavity in its central part contains a hollow cylinder and a central rod element made inside it, rigidly fixed from the side of the distal end to the piston with their exit beyond the end surface of the cylindrical body during the movement of the piston in its direction, from the side of the proximal end of the rod element, a threaded section is made for connection with a plate mounted on the iliac crest.

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