RU2476180C2 - Device for osteosynthesis of bone fractures - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, in particular to traumatology and orthopedics. Device consists of plate with holes for blocked screws, made along plate and guide. Plate is made chute-shaped and contains two combined holes on ends, with perpendicularly adjoining to them grooves. Holes for blocked screws are located in two rows along plate, with axes of all holes being made at angle to longitudinal axis of plate.

EFFECT: invention ensures high stability to pulling out impact, prevention of effect of "cold welding" in screw/plate system, possibility of combination of interfragmental compression with technique of angular stability, as well as increase of strength of fixation of bone/plate system, including multi-fractional character of fracture and osteoporosis.

4 cl, 9 dwg

Description

The inventive device relates to medicine, in particular to traumatology and orthopedics, and can be used in the surgical treatment of bone fractures, including those with a multi-fragmented nature.

Known plate TPX (Tkachenko-Rutsky-Khomutov) for osteosynthesis of bone fractures (S. S. Tkachenko. "Osteosynthesis" manual for doctors. Medicine 1987, p. 43-44), consisting of two parts with different elastic-strength properties: external rigid circuit, additionally equipped with two holes with an eccentric countersink for compression with screws and a central elastic lattice. The strength of fixation of fragments depends on the location of the screws in the rigid circuit and the elastic lattice of the plate. The disadvantage of this design is the violation of the vascularization of the cortical layer under the plate, which contributes to the occurrence of osteoporosis, sequestration, delayed consolidation, fracture of the structure itself due to its many-hole structure (fractures and deformations of the retainer when exceeding the limit of plastic deformation of the plate), as well as the inability to use lockable screws.

Several common devices are also known for internal bone marrow osteosynthesis of bone fractures.

A plate developed by specialists of the Osteosynthesis Association in 1989 is described within the framework of a new concept of biological fixation - LC-DCP (Limited Contact Dynamic Compression Plate - a dynamic compression plate with limited contact). (N.V. Kornilov, E.G. Gryaznukhin. “Traumatology and Orthopedics.” A Guide for Doctors, Volume No. 1. Pages 324-325. Hippocrates 2004; Müller M., Allgover M., Schneider R., Vilinegger X. Guide to Internal Osteosynthesis, 1996 Page 241) This plate minimizes damage to the periosteum due to its design, which favorably affects blood circulation and does not prevent the formation of bone bridges under the plate itself near the fracture gap. However, this design cannot be used in the presence of osteoporosis, because the plate performs its function only if its lower surface is firmly pressed to the bone. This creates friction between the structure and the bone, allowing mechanical forces to be transferred from one fragment to another.

Known plate LISS (Less Invasive Stabilization System), (N.V. Kornilov, E.G. Gryaznukhin "Traumatology and Orthopedics". Guide for physicians, volume No. 1. Pages 324-325. Hippocrates 2004; Mueller M. , Allgover M., Schneider R., Wilinegger X. Guide to Internal Osteosynthesis, 1996 Page 241), equipped with round holes in one plane, and only for the introduction of lockable "self-drilling" screws, requiring an electron-optical converter and special guide handle, strict execution technology and narrow mission (distal fractures thigh and proximal tibia.

Also known is the LCP plate (Locking Compression Plate) (N.V. Kornilov, E.G. Gryaznukhin "Traumatology and Orthopedics". Guide for physicians, volume No. 1. Pages 324-325. Hippocrates, 2004, V.M. .Shapovalov, VVKhominets, SVMikhailov. Fundamentals of internal osteosynthesis, 2009, p. 53) locking compression plate. The combined hole of the LCP plate consists of two parts: one part corresponds to the shape of the LC-DCP hole through which dynamic compression can be provided by eccentric introduction of standard cortical screws, the other part has a thread that allows the head of the locked screw to be fixed perpendicular to the front surface of the plate.

The disadvantage of the LCP plate is that the holes are arranged in one row - strictly perpendicular to the front surface of the plate, which negatively affects the resistance to tearing forces. A further disadvantage is that the heads of the locked screws have a conical (wedge-shaped) shape, and as a result, “cold welding” in the screw / plate system cannot be ruled out. This, in turn, creates additional technical difficulties when it is necessary to remove metal structures.

The closest in its technical solution to the claimed (prototype) is the device Zvereva E.V. - Degtyareva A.A. for bone osteosynthesis (RF Patent No. 2133594).

The device is made in the form of a plate of rectangular cross section, containing holes for screws, the axes of which are located at different angles to the longitudinal axis of the plate. Moreover, all holes are threaded, and their axes are located in different planes. From the description of the patent it follows that it uses screws with a wedge-shaped head. Installation of the plate is carried out by pressing it and holding it on the desired site of the bone when drilling holes in the cortical through the threaded holes of the plate with subsequent screwing.

This device and its installation have the following disadvantages.

1) The wedge-shaped screw head can lead to the effect of "cold welding" and, as a consequence, to problems if it is necessary to remove the structure.

2) To adjust the distance between the bone and the plate, a special holder is needed - the technique of performing the intervention is complicated.

3) Work with the device does not provide for the use of a threaded drill guide. In order to prevent the loss of the point of application of force and angular displacements during screw insertion, it is necessary to use a threaded drill guide. From the description it follows that its use is not provided, which in turn will lead to the fact that the locked screw will be screwed with a skew.

4) In the prototype there are no combined holes that allow you to perform dynamic interfragmental compression.

The aim of the proposed technical solution is to create a device that ensures the reliability of osteosynthesis and reduce the damaging effects of the structure on the bone.

To achieve this goal, a device is proposed consisting of a trough-shaped plate with holes for lockable screws, universal and threaded guides for forming channels with a given angle of insertion of screws into the bone. In the proposed plate, the holes for the locking screws are arranged in two rows along the plate, while the axes of all holes are made at an angle to the longitudinal axis, which increases the stability of osteosynthesis and resistance to tearing effects due to the "anchor effect" achieved by a given deflection of the screws. On the upper surface of the plate, continuous and intermittent soldering is applied in the opposite direction, indicating the “optimal” holes for the insertion of locked screws. The head of the lockable screw and the inlet of the hole in the cylindrical plate.

The technical result of the invention is high resistance to tearing effects, preventing the effect of "cold welding" in the screw / plate system, the possibility of combining dynamic interfragment compression with the technique of angular stability, as well as an increase in the strength of fixing the structure of the bone / plate system, including with multi-fragmented nature fracture and osteoporosis.

The inventive device is illustrated by drawings.

Figure 1 - plate for osteosynthesis of bone fractures (top view).

Figure 2 - section of the plate in the frontal plane.

Figure 3 - plate assembly with screws (front view).

Figure 4 - plate assembly with screws (side view).

Figure 5 - the angles of the axes of the combined holes for screws and holes for Kirschner spokes in a transverse section (side view).

Figure 6 - supporting surface of the universal guide (bottom view).

7 is a universal drill guide used in the formation of the channel for the cortical screw (side view).

On Fig - threaded drill guide used in the formation of the channel for the locking screw (side view in cross section).

Figure 9 is a diagram: a variant of the introduction of screws using soldering landmarks.

A device for osteosynthesis of bone fractures consists of a osseous plate 1 with holes 2 for lockable screws (figure 1). The plate has a grooved shape (figure 2), and the number of holes for locking screws depends on the intended segment. The plate also contains two combined holes at the ends 3 of an oval shape. The presence of two rows of holes for the introduction of lockable screws allows you to choose the "optimal" combination of holes used based on the nature of the fracture. Structurally, the insertion of lockable screws relative to the horizontal axis of the plate is set in such a way that the fixation of the bone fragments occurs as a “trapezoid”. This feature allows screws to cut into a compact bone layer with a large number of threads. For patients with severe osteoporosis, this effect is very effective. Due to the angular deviation of the screws in the combined holes from the center of the plate to the periphery, it is possible to use short plates in comparison with similar structures in which the screws are inserted perpendicular to the longitudinal axis of the plate. The countersink of the holes 4 for the locking screws 5 (Fig. 3) is made according to the radius of the plate so that in the bone marrow canal (in the frontal plane) the locked screws converge to its center, and in the horizontal plane they deviate in different directions relative to the perpendicular to the plane of the plate (Fig. four). The original combined hole 3 is made with a given angle of deviation from the longitudinal axis of the plate and bone (Fig. 5) of the inserted cortical or lockable screw, which makes it possible to use “short” plates and enhances the rigidity of the structure. The angle 6 (figure 5) in the combined holes and openings for lockable and cortical screws can vary between 10-12 °, depending on the location of application of the device. On the upper part of the plate, recesses 7 are perpendicularly adjacent to the combined holes 3, intended for the location of the supporting surfaces 8 of neutral AA and load BB conductors (Fig.6), a universal guide 9 with a handle of arbitrary length, convenient for holding in the hand of the surgeon, (Fig.7), including neutral 10 and load (eccentric) 11 conductors. This guide is used when forming a channel for the cortical screw with a drill. It sets the angle of introduction of the drill relative to the frontal plane of the plate. At the ends of the plate, holes were made for the Kirschner knitting needles 12 (Fig. 5), which allow you to pre-center (position) and fix the plate on the bones, and also use them when holding the device on the basis of the "pulling ligature" principle. Both ends of the plate are pointed 13, which makes it possible to conduct the subperiosteal plate. On the upper surface of the plate (Fig. 1) a continuous 14 and in the opposite direction intermittent 15 soldering is applied, indicating holes that are “optimal” for introducing screws. Compliance with the order and sequence of insertion of cortical and / or blocked screws through the plate openings into bone fragments, focusing on continuous or intermittent brazing, will avoid excessive bending loads in the bone / plate system, leading to deformation and fracture of the metal structure, which in turn will lead to repeated fracture, delayed consolidation or the formation of a false joint. On the lower surface of the plate (Fig. 4), grooves 16 are made, providing limited contact with the surface of the bone and enabling careful care of periosteal blood supply under the plate. In order to prevent the loss of the fixation point of the application of force and angular displacements when introducing lockable screws, a threaded drill guide 17 (Fig. 8) is required, having a thread 18 in the distal part, corresponding to countersinking in the combined holes 3 and all holes for the locked screws 2.

Implementation of the proposed device is as follows. After surgical access to the bone, fragments are compared. For simple fractures (type A - AO classification), interfragmental compression is performed with a cortical compression screw. After that, plate 1 is placed on the bone and temporarily fixed with Kirschner spokes in the holes 12. The first (I) and second (II) screws are inserted into the combined holes 3 (Fig. 9). After evaluating the fracture line, the optimal direction of insertion of the screws into the holes is selected: by continuous or intermittent brazing. If the direction of continuous soldering 14 is chosen, then the third (III) lockable screw after channel formation is inserted into the corresponding hole. From the other end of the plate, the screws are also inserted in the direction specified by continuous soldering. And so, 3-4 screws per bone fragment. This principle is illustrated by the example of the introduction of three screws into the proximal and distal fragments (Fig.9). Subject to this principle, the inserted screws form a “internal retainer” with a plate in the form of a trapezoid in each bone fragment, at the same time, the screws do not conflict with each other due to a given countersink angle, and there is no overload in the hole formed in the bone . Tips-guides with tactile contact under the surgeon’s finger help to choose the optimal combination of screw insertion given by the design features of the plate, and in particular, the direction of the countersink holes for locked screws.

Device allows

- make bone osteosynthesis of any closed fracture of a long tubular bone, regardless of the type of fracture;

- to increase the stability and rigidity of fixation due to the design features of the location of the screws in the cortical layer of the bone based on a given angle of introduction;

- reduce the length of the incision during access and trauma of soft tissues due to the fact that the bone osteosynthesis system using the proposed plate is a tool that implements the idea of biomechanically perfect stabilization using a durable short implant.

Claims (4)

1. A device for osteosynthesis of bone fractures, consisting of a plate with holes for lockable screws made along the plate, characterized in that it further comprises a guide, the plate is gutter-shaped and contains two combined holes at the ends with perpendicularly adjacent recesses, holes for blocked screws are arranged in two rows along the plate, while the axis of all holes are made at an angle to the longitudinal axis of the plate. 2. The device according to claim 1, characterized in that at the ends of the plate holes are made for Kirschner knitting needles. 3. The device according to claim 1, characterized in that the holes for the locking screws have a cylindrical shape. 4. The device according to claim 1, characterized in that the furrows are made on the lower surface of the plate.

Images