RU66182U1 - EXTERNAL FIXATION DEVICE FOR TREATMENT OF FRACTURES OF THE calcaneus - Google Patents

Abstract

The apparatus consists of a support beam on which a rod moving along the length and a fixed guide rod are mounted on the rotation nodes, on which a fixed support sleeve is mounted, and along which a movable sleeve with a bracket with a longitudinal groove and a shortened threaded shank mounted in it slides. In the longitudinal groove of the bracket with the ability to move installed bolt-spokesazhim. Brackets are attached to the supporting beam with bolts-clamps for fixing the spokes through the front section of the calcaneus and through the front section of the foot. The support beams are connected by threaded rods, during the breeding of which the spokes are tensioned. When the apparatus is applied, the springs are in a fully compressed state and then, as the nuts located behind the movable sleeve are loosened, they are distracted at a given angle with a predetermined force not exceeding the threshold of pain (Weber-Fechner law). During reposition, the angle may increase or decrease by tightening or loosening the nuts at the lower end of the moving rod. Spokes through the front of the foot are held through points determined by the principle of the "golden section".

Description

The device belongs to utility models and is used in medicine for the treatment of calcaneus fractures with displacement of fragments.

For the first time, the apparatus for the treatment of calcaneus fractures was used by E.R. Gillet in 1930 (An apparatus for treatment of fractures of the os calcis // J. Bone Joint Surg. - 1930. - Vol.12. - No. 3. - p. 670-671). The apparatus consisted of two brackets of variable length on which a Steiman nail was fixed, held through the calcaneal tubercle or above it. The free ends of the rods were fastened in a plaster cast with a window in the area of the calcaneal tuber. MS Henderson (Fractures of the os calcis. // Surg. Gynec Obstet. - 1936. - Vol.63. - No. 6. - P.782-784) modified the apparatus of E.N. Gillet, replacing the nail with a Kirschner spoke, reinforced in brace. In our country, the method of treatment with external fixation devices was developed after the development of the principles of compression-distraction osteosynthesis (G.A. Ilizarov, 1968). Many modifications of the Ilizarov method have been proposed (Lee A.D., Levey I.P., 1977; Borovkov Yu.A., Torshilov A.N., 1985; Ziganshin I.N., Sutyushev RB, 2000). All proposed devices provide for fixing the ankle joint.

For the prototype, we have chosen the "Device for the treatment of calcaneus fractures" proposed by I.V. Fishkin (A.S. No. 1124934 (USSR), B.I., 1984. - No. 43), containing two arcs with knitting needles and spokes, connected by threaded rods and rods, characterized in that in order to ensure uniform compression along the entire line fracture, as well as the preservation of movements in the ankle and subtalar joints, one arch is S-shaped, curved, its bars are mounted with the possibility of rotation of the bar, in which the other arch is placed with the possibility of longitudinal movement, and the threaded rods are fixed perpendicular to the curved arch and equipped with clamps, pcs ngi Branche located along the arc, and their projecting ends fitted in the clamps. The described device by I.V. Fishkin (1984) is the closest in technical essence to the proposed one. The disadvantage of the apparatus is the excessive rigidity of fixation and teething of spokes in soft tissues and bones, which leads to infectious complications.

The technical result of the proposed apparatus is to improve the results of treatment of calcaneus fractures due to the introduction of a calibrated spring into the apparatus design and a rational choice of the points of the needles passing through the bones of the foot according to the "golden section" principle.

The essence of the apparatus is illustrated in Fig. 1 (apparatus diagram), Fig. 2 (appearance), Fig. 3 (photograph of the patient's foot with the apparatus attached).

The apparatus (Fig. 1) consists of a support beam (1) on which a rod (3) moving along the length and a fixed guide rod (4) are mounted on the rotation nodes (2), on which it is mounted

a fixed support sleeve (5), and through which a movable sleeve (7) slides with a bracket with a longitudinal groove and a shortened threaded shank (8) by means of a distraction spring (6). In the longitudinal groove of the bracket with the ability to move installed bolt-spokes (9). Brackets (10) are attached to the support beam with bolts-spokes for fixing the spokes through the front section of the calcaneus and through the front section of the foot. The support beams are connected by threaded rods (11), when diluted, the spokes are tensioned.

When the apparatus is applied, the springs are in a fully compressed state and then, as the nuts located behind the movable sleeve are loosened, they are distracted at a given angle with a predetermined force not exceeding the threshold of pain (Weber-Fechner law). During reposition, the angle may increase or decrease by tightening or loosening the nuts at the lower end of the moving rod.

With parameters: d (wire diameter) = 2.4 mm; D (spring diameter) = 18 mm; h (spring pitch) = 4-5 mm; n (number of turns) = 12; l spring length in neutral state) = 48-60 mm; l ₁ spring length in a compressed state) = 28-40 mm; δ (draft under load) = 20 mm; τ _max = 33 kg / mm ₂ , the allowable stress for carbon steel, the spring develops a force of P = 10 kg.

When applying external fixation devices I.V. Fishkin and our design, the question arises about the location of the spokes through the front of the foot. I.V. Fishkin held the spokes through the bones of the tarsus. This level of conduct is not advisable for two reasons:

1. The weakness of the spongy bone (the limit of tension of the spongy bone is 1.5-2.5 kg / cm, and the compact bone is 8-12 kg / cm (Oganesyan OV, 1975).

2. The venue does not comply with the Golden Section principle.

In determining the points of application of forces acting on the bones of the foot, we are guided by the principle of the "golden section". The term "golden ratio" was introduced by Leonardo da Vinci at the end of the 15th century. The "Golden Section" is the harmonious division of the whole in such a way that most of it is proportionate between the whole and its smaller part. Human foot can also be considered as a special case of the "golden section". It is known that the longitudinal arch of the foot with respect to the loaded axis is divided into two parts in the proportion of 2/3 and 1/3. When applying the apparatus of our own design, we used the principle of the "golden section", which can be expressed as fractions 2/3, 3/5, 5/8 ..., where 2, 3, 5, 8, 13 ... are the Fibonacci numbers.

The points of the spokes are shown in Fig. 4 and 5. The point of holding the knitting needle through the forefoot (A) is determined by an x-ray using a cliche mesh. The segment between the point of the knitting needles through the calcaneal tubercle (B) and the anterior section of the calcaneus (C) is a small segment, and the segment from the spoke drawn through the front section of the calcaneus to the point of the knitting of the needle through the forefoot will be a large segment of the golden section. For example, CB = 3 cm, therefore, AC = 5 cm.

Thus, the spokes through the forefoot will always pass through the compact structure of the metatarsal bones, which ensures

margin of voltage limit and rational distribution of loads in the apparatus according to the principle of the "golden section".

The direction of the forces acting on the foot bones in the XAY coordinate system at the points of their application is shown in Fig. 6.

A ₁ is the direction of the force at point A (front of the foot), B ₁ is the direction of the force at point B (the front of the calcaneus), C ₁ is the direction of the force at point C (calcaneal tuber), and b are the distances between points, α is the reposition angle.

The developed forces at points A, B and C with constant P depend on the distance between the spokes of the apparatus a and b and the magnitude of the reposition angle α.

The external fixation device for the treatment of calcaneus fractures is used as follows.

Indications for use of the apparatus are all calcaneal fractures with displacement of fragments, with the exception of marginal and fragmented fractures.

The operation can be performed under any anesthesia: anesthesia, conduction, intraosseous or local anesthesia.

The patient is lying on his back. The foot is laid on a special or any other stand with a hanging foot. Guided by marks made with the help of a marking ruler, Kirschner knitting needles or knitting needles from the Ilizarov set are passed through the bones of the foot, and two intersecting knitting needles through a large fragment of a tuber are carried out at an angle of 30 ° relative to each other or in parallel and are fixed in the spokes of the movable bushings. The springs are in the maximum compression position. Knitting needles through the anterior calcaneus and anterior

department of the foot, are fixed in the spokes located on the respective brackets. The tension of the spokes is carried out by breeding beams using three threaded rods. The reposition angle can be set in advance or gradually during the reposition period, depending on the nature of the fracture. Smoothly controlled reposition is carried out by gradually loosening the nuts located behind the movable sleeves, as well as the nuts at the ends of the movable rods, both simultaneously on the operating table, and gradually over a period of 2-8 days, depending on the nature of the fracture, the magnitude of the edema, and the state of tissue trophism . Control x-ray is taken in 2 projections. Movement in the ankle joint begins on the day of surgery. Walking with crutches without load - from the first day. The patient can be discharged for outpatient treatment after 2-3 days. The fixation period in the apparatus is 6-8 weeks without subsequent application of a plaster cast. Dosed load (walking with one crutch) after 8-10 weeks, walking with a cane is allowed after 10 weeks, full load after 12 weeks. Return to work after 16-20 weeks.

Clinical example: patient B. V.A., 33 years old. Case history No. 246, unemployed. Injury 03/26/97 when falling from a height of about 3 meters. He entered the traumatology department of the Kineshem CRH on March 26, 1997 with a diagnosis of closed fracture of the left calcaneus bone type SB with displacement of fragments. 04.03.97 under local anesthesia, transosseous osteosynthesis of a fracture by an apparatus of its own design. The patient is lying on his back. The foot is laid on the stand, while the foot extends beyond its edge. Guided by marks made using a marking ruler through the bones of the foot

two crossing knitting needles were passed through a large fragment of a tuber at an angle of 30 ° relative to each other and were fixed in the spokes of the movable bushings. The springs were in the maximum compression position. Through the front section of the calcaneus of the foot, one spoke and two knitting needles were drawn through the front section of the foot, at points calculated according to the "golden section" principle. These knitting needles are fixed in the spokes located on the corresponding brackets. The spokes were tensioned by breeding the beams using three threaded rods.

The reposition angle is set in advance. Smoothly controlled reposition is carried out by gradually loosening the nuts located behind the movable sleeves, as well as the nuts at the ends of the movable rods simultaneously on the operating table. Fragment displacement eliminated. The postoperative period without complications. Discharged for outpatient treatment 6 days after surgery. The device is removed 05/13/97. The fusion of the calcaneus has been achieved in the correct position. Beler angle 30 °. The term of treatment is 100 days. The result is recognized as good.

When using the proposed "apparatus for the treatment of calcaneus fractures" the following features are provided:

1. the apparatus is made from parts of the Ilizarov kit and provides reposition and fixation of fragments under smoothly controlled loads;

2. The calibrated spring provides smoothly controlled loads during reposition and fixation, removing excess stresses in the spoke-bone system;

3. The device allows you to minimize the likelihood of teething knitting needles in the bone and soft tissues, reducing the risk of infectious complications. Using the apparatus for treating 8 patients with 9 fractures of the calcaneus, we did not note such complications.

Claims (1)

External fixation device for the treatment of calcaneus fractures, characterized in that the fixation of the calcaneus fragments is carried out by means of knitting needles with the ability to move bolts - spokes in the longitudinal grooves of the brackets with a shortened threaded shank installed in a movable sleeve that slides along the guide rods using a calibrated spring.