RU206668U1 - KNEE SPACER - Google Patents

Abstract

The utility model relates to the field of medicine, in particular to medical technology. The objective of the utility model is to reduce the risks of: - postoperative subluxation of the spacer and lower leg; - formation of adhesions and contracture; - recurrence of joint infection; increased stability and strength of the spacer; Technical result: reduced rotation spacer legs; exclusion of excessive mobility between the femoral and tibial components; exclusion of reuse of the removed femoral component. This is achieved by the fact that the femoral component is reinforced and made to the size of the removed femoral component of the endoprosthesis, while its anteroposterior part is extended by 1.0 cm, and between its rear sections are made of a reinforced jumper, forming a hole. Anti-rotational ribs are formed in the leg of the tibial component. The threaded axial rod, made in the form of a screw, protrudes 1.5 cm above the proximal surface of the plateau and is covered with cement.

Description

The utility model relates to the field of medicine, in particular to medical equipment used in traumatology and orthopedics, and is intended for performing surgical interventions in the treatment of patients with infectious complications after knee arthroplasty, including the installation of a "temporary" implant.

Endoprosthetics of large joints is the method of choice for severe joint diseases, especially in elderly and senile people. In recent years, there has been a tendency to perform arthroplasty in middle-aged people. This operation makes it possible to activate the patient and improve the quality of life. At the same time, the observed increase in the number of arthroplasty led to an increase in various complications. The most difficult and intractable of them is deep suppuration of the area of surgical intervention, which occurs up to 3-4% [Lyubo, Tikhilov R.M., Shubnyakov I.I., Bozhkova S.A., Artyukh V.A., Denisov A.O. Analysis of the effectiveness of sanitizing operations for periprosthetic infection. Traumatology and Orthopedics of Russia 2014; (2): 22-29].

The gold standard for the treatment of deep periprosthetic infection is two-stage re-endoprosthetics. The first stage is a sanitizing operation - removal of the endoprosthesis, surgical treatment of a purulent focus and installation of a spacer. The second stage is the re-implantation of the endoprosthesis.

An important point in the first sanitizing stage of treatment is the correct selection of the articulating spacer, which ensures the preservation of bone tissue, bones forming the joint, joint function, reduction of recurrence of infection, prevention of instability of the spacer and contracture of the knee joint, which make it easier to re-insert the endoprosthesis.

Known "Articulating spacer of the knee joint" [RU 88532 U1, 2009], containing the femoral and tibial components, while the femoral component is equipped with a thin-walled liner made of nanoceramic porous biocompatible material, repeating the geometry of the articulation with the tibial component. The tibial component has depths of up to 12 mm, corresponding to the thickness of the liner.

The disadvantage of this useful model is the use of expensive materials in the manufacture of preformed spacers, which limits this method for wide clinical practice. The absence of a reinforcing component of the tibial component of the spacer can lead to destabilization of the latter.

Known "Articulating spacer of the knee joint with intramedullary fixation" [RU 95254 U1, 2010], containing the femoral and tibial components, characterized in that each component is equipped with a cylindrical intramedullary element 12 cm and 10 cm long, respectively, reinforced with three wires of the "Kirchner" type and rigidly connected with the articulating surface and repeating the diameter of the medullary canal. The disadvantage of the spacer is:

- the formation of adhesions between the femur and soft tissues, which can lead to contractures in the joint;

- instability of the spacer and joint.

Known "Knee joint spacer" [RU 136702 U1 2014], made of bone cement containing an antibiotic, in the form of two spatial figures, in shape and size corresponding to the removed elements of the endoprosthesis, characterized in that the element covering the distal femur , in the form of two conjugated fragments of spherical bowls, perforated radially in the anterior and posterior sections, the mushroom-shaped element in contact with it, covering the tibial plateau of the tibia, is made with horizontal perforation of the cap, and its stem - with longitudinal perforation, while both elements are perforated repeatedly and through and through, and their mutual contact surfaces remain intact.

The disadvantages of the utility model are the low stability of the spacer components, and the presence of perforations leads to a decrease in the spacer strength, which can cause mechanical damage and fragmentation of the components both during loading and during the removal of the spacer during re-endoprosthetics.

As a prototype of the claimed utility model, a knee joint spacer was selected [RU 160123, 2016].

The essence of the proposed device is that the spacer consists of the femoral component of the removable endoprosthesis, as well as the tibial component, which is a reinforced stem made of bone cement and a figured plate, which is essentially a plateau that repeats the shape and size of the removed tibial, that is, the tibial component of the endoprosthesis knee joint, on the distal side of which there is a seat and made of bone cement containing an antibiotic. Moreover, the leg consists of a threaded axial rod and type-setting blocks made of bone cement with a rough surface and thread along the internal axis. The outer sheath of the spacer leg is made from bone cement with antibiotic.

The disadvantages of the prototype are:

The leg of the spacer in the form of an axial rod does not impede its rotation, which can cause instability of the tibial component.

Risk of adhesion between the femur and soft tissue, which can lead to joint contractures.

Risk of subluxation of the spacer and lower leg, due to the lack of interconnected elements that ensure stability in the joint.

Reuse of the removed femoral component may lead to recurrence of joint infection.

The lack of reinforcement of the plateau of the tibial component of the spacer is a risk of fracture during the development of the joint and movement in it.

The task set for creating a utility model is:

risk reduction:

- postoperative subluxation of the spacer and lower leg; - formation of adhesions and contractures of the knee joint, which will simplify the implementation of the second stage of re-endoprosthetics; - recurrence of joint infection;

increasing the stability and strength of the spacer.

The technical result achieved with the claimed utility model is:

reduced rotation of the spacer leg;

elimination of excessive mobility between the femoral and tibial components of the spacer;

elimination of reuse of the removed femoral component.

The technical result is achieved by the fact that the knee joint spacer made of bone cement with an antibiotic includes a femoral component in the form of 2 hemispheres conjugated along the front upper surface and a tibial component, which is a leg reinforced with a threaded axial rod. The femoral component is reinforced and made to the size of the removed femoral component of the endoprosthesis by pouring cement into casting molds. The anterosuperior part of the femoral component is extended by 1.0 cm. Antirotational ribs are formed in the stem of the tibial component, corresponding to the dimensions of the notches in the proximal tibia remaining after the removed tibial component of the endoprosthesis. The threaded axial rod is made in the form of a screw and protrudes 1.5 cm above the proximal surface of the plateau, forming a protrusion that is covered with cement. Between the posterior parts of the femoral component, a reinforced bridge is formed, forming an opening, the diameter of which is 1.0 cm greater than the diameter of the aforementioned protrusion above the proximal surface of the reinforced plateau.

Distinctive essential features and a causal relationship between them and the achieved result:

The hip component of the spacer is reinforced to increase its strength.

The femoral component of the spacer is made according to the dimensions of the removed femoral component of the endoprosthesis by pouring cement into the casting molds, which allows maintaining the size of the removed femoral component of the endoprosthesis.

The anterosuperior part of the femoral component is extended by 1.0 cm, which prevents the formation of adhesions and, therefore, prevents the development of contracture of the knee joint and facilitates the implementation of the second stage of re-arthroplasty.

The tibial plate is reinforced to increase the strength and stability of the knee spacer.

Antirotational ribs are formed in the stem of the tibial component, corresponding to the dimensions of the notches in the proximal tibial bone after the removed tibial component of the endoprosthesis, which prevents rotation of the tibial component and ensures its stability.

The threaded axial rod, made in the form of a screw, protrudes 1.5 cm above the proximal surface of the plateau, forming a protrusion, which prevents excessive mobility between the femoral and tibial components of the spacer, thereby helping to stabilize the components of the spacer and preventing lower leg subluxation.

The protrusion above the proximal surface of the plateau is covered with cement, which prevents damage to the cemented femoral component of the spacer.

Between the posterior parts of the femoral component, a reinforced bridge is made, forming an opening whose diameter is 1.0 cm larger than the diameter of the protrusion above the plateau of the tibial component to allow free movement of the lower leg in the knee joint, which allows both components to be firmly connected and maintain stability and mobility in the joint.

The threaded axial rod in the form of a screw facilitates the removal of the tibial component when performing re-endoprosthetics.

The set of essential distinctive features is new and ensures the achievement of the technical result and the accomplishment of the objective of the invention.

The essence of the utility model is illustrated in FIG. 1 - General view of the spacer, Fig. 2 - View of the proximal tibia in the horizontal plane and FIG. 3 - View of the spacer in the frontal plane, where:

1. femoral component;

2. two conjugate hemispheres;

3. spoke for the formation of the bridge;

4. jumper;

5. hole in the femoral component;

6. a curved spoke inserted into the hemispheres of the femoral component;

7. anterosuperior part of the femoral component;

8. tibial component;

9. a curved spoke placed in a plateau;

10. plateau of the tibial component;

11. Threaded axial rod, made in the form of a screw;

12. the leg of the tibial component;

13. anti-rotation ribs of the tibial component;

14. notches of the tibial component;

15. ledge.

The proposed utility model can be used as follows:

A midline incision is made to cut the skin along the anterior surface of the knee joint. From the medial side of the patella, arthrotomy is performed. The femoral component of the knee endoprosthesis is removed. Mechanical and medical treatment of the joint cavity is performed. A shape is selected in size, corresponding to the size of the removed femoral component, into which bone cement with an antibiotic is poured to make the femoral component (1), which is two conjugated hemispheres (2). Before the final polymerization of the bone cement, a needle (3) is inserted into the posterior inferior part of two conjugated hemispheres (2), forming a bridge (4), thus forming a hole (5). A curved needle (6) is inserted into the conjugated hemispheres (2), in order to reinforce them, and the anteroposterior part (7) of the femoral component (1) is extended by 1.0 cm.

The tibial component of the endoprosthesis is removed. Mechanical and medical treatment of the joint cavity is performed. A tibial component (8) is formed from bone cement with an antibiotic, which includes a plateau (10) reinforced with a curved needle (9) and a leg (12) reinforced with a threaded axial rod (11), made in the form of a screw (12), containing anti-rotational ribs (13) corresponding to the dimensions of the recesses (14) remaining after the removed tibial component of the endoprosthesis (14) in the proximal part of the tibia. thus forming a protrusion (15) which is covered with cement. The height of the plateau corresponds to the height and shape of the removed polyethylene insert of the endoprosthesis. In the horizontal direction, during the polymerization of the cement, a curved wire (9) is placed inside the cement in the plateau for the purpose of reinforcement. Before the end of polymerization, with the knee joint maximally bent, the leg of the spacer on cement with an antibiotic is installed with the formed tibial (8) and femoral components (1) of the spacer.

The knee joint is extended so that the protrusion (15) above the proximal surface of the plateau (10) of the tibial component of the spacer enters the hole (5) of the femoral component (1) of the spacer, then it is again flexed 2 times, which gives the articulating surfaces of the tibial (8) and femoral ( 1) components of the maximum correspondence, which does not restrict movement in the joint. Excess cement is removed, the knee joint is extended and held in a stretched position until the cement is completely polymerized.

After the end of polymerization, the stability of fixation of the components, the range of motion in the joint are checked, if necessary, excess fragments of the squeezed out cement are removed. Hemostasis is performed, the wound is washed abundantly with antiseptic solutions using pulse lavage. Install a low-vacuum drainage system. The wound is sutured in layers. The joint is immobilized.

The proposed useful model was tested in 18 patients at the Department of Purulent Surgery at the Clinic of Traumatology and Orthopedics of the N.N. I.I. Mechnikov.

Here is a clinical example:

Patient A., 62 years old, was being treated at the clinic of the North-Western State Medical University named after V.I. I.I. Mechnikov with a diagnosis of Right-sided gonarthrosis stage 3-4. In 2015, an endoprosthetics of the right knee joint was performed. Postoperative course without complications. 2 years after the injury (a fall on the right knee joint), edema, a local increase in temperature, hyperemia in the knee joint appeared. From April 18, 2017, the patient was treated in the traumatology clinic at the purulent osteology department, where, based on the data of clinical laboratory, X-ray and microbiological (st. Aureus) studies, the diagnosis "Deep periprosthetic infection of the right knee joint" was established. 04/26/2017 operation - Revision of the right knee joint. Removal of endoprosthesis components, subtotal synovectomy. Implantation of a two-piece spacer of the right knee joint.

The course of the operation: under spinal anesthesia in the position of the patient on his back, with a bent knee joint. A 0.1% aqueous solution of brilliant green was introduced into the sinus tract. An incision was made along the anterior surface of the right knee joint along an old postoperative scar 20 cm long with excision of the latter and fistula. The skin, tissue, fascia were dissected. The knee joint was visualized using the media parapatellar approach; a significant amount of liquid stained with dye was obtained from the joint cavity. Revision: revealed total staining of the synovial membrane and bone tissue with 0.1% aqueous solution of brilliant green, purulent granulation.

Subtotal synovectomy was performed after maximum isolation of the synovial membrane in a blunt way and with the help of an electrocoagulator. The removed soft tissues were sent for histological and bacteriological examination.

The signs of instability of the components of the endoprosthesis were revealed. The insert (Zimmer, size E-F / 10 mm), femoral (Zimmer, size F) and tibial (Zimmer, size 5) components of the endoprosthesis were removed in stages. Revision of the subprosthetic surfaces of the knee bones: destruction of the anterosuperior femur over 1 cm was revealed. Surgical treatment of foci of non-viable bone tissue was performed, and the remains of bone cement were removed. Scar tissue, purulent granulations are excised. The joint cavity is abundantly washed with a solution of antiseptics using pulse lavage. Thorough hemostasis.

For the manufacture of the femoral component of the spacer, a casting mold was selected in size, corresponding to the size of the removed femoral component of the endoprosthesis, into which bone cement with an antibiotic was poured. At the same time, the anteroposterior part of the femoral component was lengthened by 1.0 cm in comparison with the removed femoral component of the endoprosthesis. During the polymerization of the bone cement, a curved wire was inserted into the conjugated hemispheres of the formed spacer. A second spoke is inserted between the rear hemispheres of the formed cement spacer, forming a reinforced bridge, which is covered with cement. In this case, a hole was formed in the femoral component of the spacer between the hemispheres and the bridge. With the knee joint maximally bent, the femoral component of the spacer was installed on cement with an antibiotic until the end of polymerization.

A plateau and a stem of the tibial component of the spacer in shape and size, the removed tibial component of the endoprosthesis, were formed from bone cement with an antibiotic. In the horizontal direction, during the polymerization of the cement, a curved wire was placed in the plateau in order to reinforce it. Before the final polymerization of the cement, a threaded axial rod in the form of a screw protruding above the plateau surface by 1.5 cm was screwed into the tibial stem from the proximal part of the plateau, forming a protrusion that is covered with cement. The height of the plateau corresponded to the height of the removed polyethylene insert of the endoprosthesis.

With the knee joint maximally bent, the tibial component of the spacer is installed on cement with an antibiotic until the end of polymerization.

The knee joint was extended so that the proximal part of the screw, protruding above the plateau surface, entered the hole of the femoral component of the spacer. Then the knee joint was bent 2 times, which gave the articulating surfaces of the tibial and femoral components maximum correspondence and made it possible not to restrict movement in the joint. Excess cement was removed, the knee joint was extended and held in this position until the cement was completely polymerized.

After the end of polymerization, the stability of fixation of the components and the range of motion in the joint were checked. Removed excess fragments of extruded cement.

Produced hemostasis, the wound was washed abundantly with antiseptic solutions using pulse lavage. A low-vacuum drainage system was installed. The wound was closed in layers. A drainage tube was installed through a counter-opening. The joint was immobilized.

In the postoperative period, the patient received antibiotic therapy in accordance with the antibiogram data. The operating wound healed by primary intention. The patient began to walk with a dosed load on the operated leg. Five months later, the final (second) stage of revision arthroplasty of the right knee joint was performed. After 4 years, the long-term result was assessed as good.

Using this technique, 18 patients were operated with good results. All patients had no spacer fracture or instability. Complications in the form of postoperative subluxation of the spacer and lower leg, adhesions and contracture of the knee joint, as well as recurrence of joint infection were not observed.

Claims (1)

A knee joint spacer made of bone cement with an antibiotic, including a femoral component in the form of 2 hemispheres conjugated along the anterior upper surface and a tibial, which is a leg and a plateau reinforced with a threaded axial rod, corresponding to the shape and dimensions of the removed tibial component of the knee endoprosthesis joint, characterized in that the femoral component is reinforced and made according to the size of the removed femoral component of the endoprosthesis by pouring cement into casting molds, the anteroposterior part of the femoral component is extended by 1.0 cm, anti-rotation ribs are formed in the tibial component stem, corresponding to the dimensions remaining after the removed tibial component endoprosthesis of notches in the proximal tibia, the threaded axial rod is made in the form of a screw and protrudes 1.5 cm above the proximal surface of the plateau, forming a protrusion that is covered with cement; between the posterior parts of the femoral component, a reinforced bridge is formed, forming an opening, the diameter of which is 1.0 cm greater than the diameter of the aforementioned protrusion above the proximal surface of the plateau, which is reinforced.

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