RU166284U1 - INTRAMEDULAR BLOCKING DEVICE FOR OSTEOSYNTHESIS OF FEMOR FRACTURES - Google Patents

Abstract

1. An intramedullary blocking device for osteosynthesis of femoral fractures, which is an extended body in the form of a trihedral rod curved along an arc with pointed ribs and a longitudinal axial through channel with the possibility of passing a guide through it, on one side the rod is made pointed, has sections with notches along the type of rasp to ensure the possibility of expanding the diameter of the medullary canal in the cortical layer with the introduction of the device and in one of its ribs located on a convex the surface of the rod, a recess for introducing a locking screw; on the opposite side, the rod is made expanding outward from the central axis toward the end face on which the removable cover is fixed, with the possibility of ensuring the transition of its two ribs into flattened plates of a triangular shape, characterized in that the third rib is made in the area of the expansion of the rod towards one of its ends with a transition to a rounded protrusion, through the central longitudinal axis of the rod between the plates and the rounded protrusion, there are through transverse channels for locking screws. 2. The device according to claim 1, characterized in that in addition to the second rib from the side of the pointed end of the rod there is a recess for introducing locking screws.

Description

The utility model relates to medical equipment used in traumatology. This technical solution is intended for the surgical treatment of fractures of the tubular bones, in particular the distal femoral diaphysis, by performing intramedullary osteosynthesis with retrograde insertion of the intraosseous shaft.

There are various designs of intramedullary blocking devices [SU copyright certificates for inventions No. 1454430, No. 1787020, RU patents for inventions No. 2102027, No. 2120790, RU patents for utility models No. 47658, No. 61542, No. 100717]. All of them have an extended body in the form of a rod with a rectangular cross section.

Also known is the "Fixator for the treatment of fractures of the tubular bones" [copyright certificate SU for the invention 992041], made in the form of a three-blade rod. In order to increase the rigidity of fixation of bone fragments on the blades of the shaft, grooves are made.

However, with the introduction of this fixative, the elastic blades of the rod, deforming, fill the medullary canal along the entire length, taking the shape of the canal and providing close spring-loaded contact with its walls. This fact negatively affects the integrity of the intraosseous vessels that affect bone fusion.

The magnitude of the spring-loaded effect is difficult to calculate taking into account different anthropometric characteristics of people, which can negatively affect the initial stiffness of fixation of bone fragments. Ensuring constant close contact of the fixative with the walls of the bone marrow canal leads to necrotization of the tissues of its adjacent surface, being a focus of aseptic inflammation, and in the presence of pathological microorganisms, it is possible to go into the phase of septic inflammation, which will require a change in treatment tactics.

The closest analogue to the claimed utility model is "Intramedullary blocking device for osteosynthesis" [RU patent for invention No. 2526242]. The device comprises an extended body in the form of a trihedral rod with pointed ribs, proximal and pointed distal ends, a longitudinal axial through channel with the possibility of a guide through it. A removable cover is fixed on the end side of the proximal end of the body. The rod is made expanding outward from the central axis toward the proximal end. From the side of the distal end of the rod, sections with incisions of the rasp type are made on its ribs to provide the possibility of expanding the diameter of the medullary canal in the cortical layer with the introduction of the device. At least one of the ribs from the side of the distal end of the rod has a recess for introducing a locking screw.

However, this device can be used only with antegrade insertion of the rod, and therefore its design features are aimed at the use of the device in the treatment of fractures of the femoral diaphysis and its proximal end. The treatment of fractures of the distal femur by using this device is associated with damage to one of the stiffeners of the rod of the anterior femur. And the absence of jamming devices (locks) in this area reduces the degree of fixation stiffness and can lead to the migration of the rod into the cavity of the knee joint.

The objective of the claimed utility model is the development of an intramedullary blocking device that provides reliable and durable fixation of fragments during retrograde insertion of the rod, taking into account the anatomical form of the pineal gland of the hip, eliminating the risk of complications.

The essence of the claimed utility model lies in the fact that in the intramedullary blocking device for osteosynthesis of fractures of the femur, which is an extended body in the form of a trihedral rod curved in an arc with pointed ribs and a longitudinal axial through channel with the possibility of a guide through it, from one side the rod made pointed, has sections with notches like a rasp to ensure the possibility of expanding the diameter of the medullary canal in the cortical layer with the introduction of the mouth rostomy and in one of its ribs, located on the convex surface of the rod, there is a recess for the introduction of a locking screw; on the opposite side, the rod is made expanding outward from the central axis towards the end face on which the removable cover is fixed, with the possibility of ensuring the transition of two of its ribs into flattened plates of a triangular shape, in the area of expansion of the rod towards one of its ends, the third rib is made with the transition to round protrusion, through the central longitudinal axis of the rod between the plates and the rounded protrusion, there are through transverse channels for locking screws.

A device with the above-described features is also claimed, in which a recess for introducing locking screws is made in the second rib from the side of the pointed end of the rod.

The technical result of the claimed utility model.

The set of developed design features of the claimed device, consisting in the presence of a section with an extension of the diameter of the rod from one of its ends without increasing the radius of the body in the area of the rib, turning into a rounded protrusion, turning the rod into a figure with two asymmetrically located faces, which allows placement in the central zone through channels for locking screws, allows for reliable and durable fixation of fragments with the formation of bilateral compression during retrograde by the introduction of the rod, taking into account the anatomical shape of the pineal gland and the relatively weak bone structure of the distal limb, excluding the possibility of eruption (exit) of the structure close to the front edge of the metaepiphysis of the femur. The above signs can expand the possibility of using this device in the treatment of fractures of the distal femur.

The inventive utility model is illustrated using FIG. 1-3, in which: FIG. 1 is a perspective view of an intramedullary blocking device for osteosynthesis of femoral fractures, FIG. 2 is a side view of the device on which a removable cover is mounted; in FIG. 3 is a view of the inventive device installed in the femur.

1 - rod;

2 - ribs;

3 - axial through channel;

4 - the pointed end of the rod;

5 - sections with notches;

6 - recesses for locking screws from the pointed end;

7 - removable cover;

8 - flattened plates of a triangular shape;

9 - a rounded ledge;

10 - through channels for locking screws. The intramedullary blocking device for osteosynthesis of femoral fractures is an extended body in the form of a trihedral rod 1 with pointed ribs 2 and a longitudinal axial through channel 3 with the possibility of passing through it a guide like a knitting needle. The device is made of a solid bioinert material with the possibility of applying polymeric materials, for example, carbon or bioceramic coatings, as well as antiseptic and antimicrobial coatings, including various metals, in particular gold, to its outer surface. The outer diameter of the rod 1 in its middle part is equal to or 1-2 mm larger than the diameter of the medullary canal of the damaged femur. The rod 1 is made curved in an arc. Depending on the anatomical segment, the bending radius is about 1500 mm.

On one side, the rod 1 is made pointed 4 to facilitate its insertion and has sections with notches 5 of the type of a rasp to enable expansion of the diameter in the cortical layer of the medullary canal when introducing the device. The length of the sections with notches 5 along the rod 1 is 30-60 mm On the side of the pointed end 4 of the rod 1 in one or more of its ribs 2 there is a recess 6 for introducing a locking screw. If the recess 6 is made alone, then it is placed on the convex surface of the rod 1. In individual cases, at least two recesses 6 for locking screws equally spaced from each other can be made in one rib 2 along the rod 1, which allows, if necessary, to lock the rod 1 at different levels and in different planes, creating high-quality fixation of fragments, especially with multi-fragmented fractures. The recesses 6 for the locking screws have a rectangular shape with a length along the body greater than the diameter of the locking screw in order to facilitate the latter falling into its corresponding recess 6.

On the opposite side, the rod 1 is made expanding outward from the central axis at least 1.5-2 times towards the end face, on which a removable cover 7 with a slot is fixed. In the center of the latter there is an opening with a diameter equal to the diameter of the axial through channel 3 of the rod 1. The extension of the rod towards the end face is carried out in the area of its two ribs 2 with the possibility of their transition into the flattened plates of a triangular shape 8. The third rib (located at the top of the bend of the rod 1 ) is made passing in the region of expansion of the rod 1 into a rounded protrusion 9 with a height of up to 2 mm Through the central longitudinal axis of the rod 1 between the plates 8 and the rounded protrusion 9 there are through channels 10 located at a distance of about 10-30 mm from each other along the housing for locking screws. Through channels 10 can be made with internal threads with a diameter of 5-7 mm. The distance from the end face of the rod 1 to the first through channel 10 is about 15 mm, the distance between subsequent through channels 10 is 25-30 mm.

The intramedullary blocking device for osteosynthesis of the femur is used as follows.

An x-ray study is carried out, which assesses the location of the fracture, the size and shape of the injured femur. The patient is placed on the operating table, the surgical field is treated and its restriction with sterile material. Under aseptic conditions, after performing a closed reposition, for example, using the device described in RU patent for utility model No. 114601, surgical access of 3-7 cm to the articular surface of the femur is performed in the position of limb flexion. A guide in the form of a spoke along the axis of the medullary canal of the thigh is inserted into the region of the intercondylar fossa under x-ray control, passing the fracture line, until the middle of the proximal fragment. A cannulated drill with a diameter of about 10-20 mm (equal to the diameter of a pre-selected rod without taking into account the protrusion of the trihedral ribs) in the cortical and metaphysical parts of the distal femur using a previously installed spoke (conductor) forms a hole before the start of the medullary canal of the distal femur. According to preliminary data obtained during an X-ray examination, a rod with the required length and diameter in the middle part equal to or exceeding the latter by 1-2 mm (depending on bone density) is taken from a set of device types and sizes. Assemble the device in working condition. To do this, fix on the housing of the rod from the side of its end with the expansion adapter type of sleeve. The pointed end of the rod is introduced along the guide in the form of a spoke, allowing it to pass through the axial through canal into the hole formed by means of a drill in the medullary canal and by pushing the adapter, the rod is advanced along the longitudinal axis of the femur. In this case, the rib turning into a rounded protrusion is oriented towards the front surface of the bone. A triangular channel is formed along the entire length of the thigh, including the cortical layer at the site of its anatomical narrowing, under the rod by moving the device’s body along the longitudinal axis of the femur with translational movements, and, if necessary, with forward and backward movements, expanding the medullary canal with ribs with on them with rasp type notches. Then, the rod is inserted before the end part of the end is immersed, expanding into the intercondylar region, while ensuring that the opposite pointed end of the rod does not reach the greater trochanter. X-ray check the anatomy of the comparison of fragments, the correct introduction of the rod and the stability of fixation. The guide is deleted.

The entire device is blocked by locking screws passing through both cortical layers of the bone, through channels and grooves in the ribs of the rod using a navigation device, fixed in addition to the adapter. The number of installed locking screws is determined individually depending on the clinical situation.

The navigation system and adapter are deleted. On the end side from the end with the extension, for example using a screwdriver or cannulated screwdriver, fix the cover with a slot. The wound is sutured in layers and proceed with rehabilitation measures. After consolidation of the fragments, the device is removed in the reverse order.

Example.

The inventive utility model is implemented in an experimental sample. By means of computer modeling, the stress-strain state of the bone-implant system was studied under three types of static loads: axial, transverse and torsional. Stresses in the shaft and bone fragments, as well as contact pressure, were analyzed. At the same time, it was confirmed that the found design improvements are biomechanically justified and justify their constructive expediency.

Claims (2)

1. An intramedullary blocking device for osteosynthesis of femoral fractures, which is an extended body in the form of a trihedral rod curved along an arc with pointed ribs and a longitudinal axial through channel with the possibility of passing a guide through it, on one side the rod is made pointed, has sections with notches along the type of rasp to ensure the possibility of expanding the diameter of the medullary canal in the cortical layer with the introduction of the device and in one of its ribs located on a convex the surface of the rod, a recess for introducing a locking screw; on the opposite side, the rod is made expanding outward from the central axis towards the end face on which the removable cover is fixed, with the possibility of ensuring the transition of its two ribs into flattened plates of a triangular shape, characterized in that the third rib is made on the expansion section of the rod towards one of its ends with the transition to a rounded protrusion, through the central longitudinal axis of the rod between the plates and the rounded protrusion there are through transverse channels for locking screws. 2. The device according to p. 1, characterized in that in addition to the second rib from the side of the pointed end of the rod is made a recess for the introduction of locking screws.

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