RU164485U1 - Intramedullary fixator for surgical and prophylactic treatment of articular joint fractures of the tubular bone on the background of osteoporosis - Google Patents

Abstract

An intramedullary fixator for the surgical treatment of periarticular fractures of the tubular bone, made in the form of a needle bent in the form of a coiled coil spring, the turns of which are parallel to each other and are located at an angle of 30-50 °, characterized in that the three distal turns are made in the form of a conical spring, which descends to the diameter of the spoke, and the final part of the proximal turn ends with a spoke having a rectangular section, the length of which is 30-35 mm, while the body of the spoke contains an intermediate hardened layer, inside a transverse dielectric bioinert layer, an external dielectric bioactive layer consisting of two layers, the first layer being made in the form of a calcium phosphate coating, and the second layer being made in the form of a coating with hyaluronic acid.

Description

Application area

The utility model relates to the field of traumatology and orthopedics and can be used for osteosynthesis and stimulation of osteogenesis in the surgical treatment of low-energy periarticular fractures of the tubular bones that occur against osteoporosis, in particular fractures of the distal radius, femoral neck fractures, fractures of the proximal humerus.

State of the art

Known fixative for osteosynthesis of fractures of the proximal femur (patent RU 94444 IPC АВВ 17/58 publ. 27.05.2010). The latch is a smooth metal rod with three sections of different sized threads. One end of the rod is pointed for insertion into the canal and screwing into the spongy tissue of the bone head. The second thread section is fixed in a denser bone of the vertical region and the cortical plate, and the third thread section is intended for fastening in an external support, which uses elements of the Ilizarov apparatus.

The fixator reliably stabilizes bone fragments only if the mineral density of the bone head is sufficiently dense. To fix loose bone tissue, the thread size (height and pitch) at the end of the shaft should be increased, but this increase is limited by the diameter of the shaft, which should be smaller than the size of the bone channel of the tubular bone.

The known fixative (EI Solod, AF Lazarev, VM Nikolaev. Stress osteosynthesis of the proximal humerus in old age. "Clinical gerontology", T. 9, 6, 2003), which contains a pair curved Y-shaped titanium spokes located in two mutually perpendicular planes.

The main disadvantage of this technical solution is the complexity and complexity of conducting curved knitting needles along the medullary canal. The ends of the bent spokes, passing through the channel, abut against its walls and tend to bend, which can lead to jamming of the spoke in the channel. In addition, for the implementation of osteosynthesis and stability at the fracture site, it is necessary to introduce bundles of (2-3) Y-shaped spokes through 2-3 perforations, which leads to additional trauma to the bone tissue. With this technique, there is a threat of migration of spokes with damage to important neurovascular formations.

Known intramedullary retainer for surgical treatment of periarticular fractures of the tubular bone (patent RU 2468764 IPC АВВ 17/72 publ. 10.12.2012), which is made in the form of a curved titanium spoke, curved in the form of a twisted coil spring, the turns of which are parallel to each other and are located at an angle 30-50 ° to the axis. The end part of the distal turn is made pointed, the end part of the proximal turn is equipped with a T-shaped lever.

The disadvantage of this technical solution is that when introducing a cylindrical spring in an antegrade way (for example: the proximal femur, ulnar process, distal metaepiphysis of the radius, lateral and medial ankle, etc.), technical difficulties arise in introducing, which leads to a wider dissection of soft tissues (skin, muscles, ligaments, etc.) and drilling a bone to a diameter equal to the outer diameter of the coil spring. Such surgical expansion negatively affects bone tissue affected by osteoporosis and increases the risk of infectious complications, and the minimally invasive element will be leveled.

Utility Model Essence

The objective of the utility model is to develop a bioactive intramedullary fixative to stabilize bone fragments and stimulate the process of osteogenesis using minimally invasive surgical access of periarticular fractures of the tubular bone against the background of osteoporosis.

The technical result of the utility model is to achieve minimally invasive, preserving bone tissue.

The technical result is achieved by the fact that in the intramedullary retainer, made in the form of a needle, curved in the form of a twisted coil spring, the turns of which are parallel to each other and are located at an angle of 30-50 °, according to the proposed solution, three distal turns are made in the form of a conical spring, which descends to the diameter of the spoke, and the final part of the proximal turn ends with a spoke having a rectangular section, the length of which is 30-35 mm, while the spoke body contains an intermediate hardened layer, an internal die an electric bioinert layer, an external dielectric bioactive layer consisting of two layers, the first layer being in the form of a calcium phosphate coating, and the second layer being in the form of a coating with hyaluronic acid.

Brief Description of the Drawings

In FIG. 1 shows the appearance of the inventive intramedullary fixative, in FIG. 2 is a photo of the fixative during retrograde insertion into the medullary canal through the perforation opening of the humerus diaphysis, in FIG. 3 is a photo of the fixative during retrograde insertion into the medullary canal through the perforation hole in the metaepiphysis of the radius or ulna, FIG. 4 is a photo of a fixator during osteosynthesis of a femoral neck fracture through a perforation hole in the cortical layer of the undervert region.

Utility Model Implementation

The proposed retainer is a knitting needle. The spoke body is multilayer and contains an intermediate hardened layer, an internal dielectric bioinert layer, an external dielectric bioactive layer. The outer bioactive layer is made in the form of a coating consisting of two layers. The first layer is made in the form of a calcium phosphate coating, the second layer in the form of a coating with hyaluronic acid. The spoke is made in the form of a cylindrical spring 1. The turns 2 of the cylindrical spring are parallel to each other and have a slope in the frontal plane to the axis OO1 of the retainer within the angle φ = 30-50 degrees. Three distal turns 3 represent a conical spring, which descends to the diameter of the spokes and has a point, which is made as a cut of the spokes at an angle of 30 degrees. The proximal turn 4 ends with a straight needle with a length L, equal to 30-35 mm with a rectangular cross-section according to the type of Kirchner spokes for a detachable T-shaped key or for fixing in the Jacobs cartridge. The angle of inclination of the coils of the conical part of the spring is chosen so that it is possible to introduce the structure without perforation through a perforation hole with a diameter of 3.0-5.0 mm in the cortical layer of the bone diaphysis, which varies in thickness from 1.0 to 3.0 mm. With these technical features, the retainer will abut against the opposite inner cortical wall of the bone and bend along the medullary canal. The diameter of the spokes S for a particular patient is selected from the required strength of the spokes and the minimally invasiveness of its introduction. Standard Kirschner spokes with a diameter of 1.0 mm to 2.5 mm are used, having sufficient elasticity and strength. The diameter of the spoke is determined by the anatomical features of the subject, the length and width of the damaged segment, the width of the medullary canal, muscle mass, etc.

For patients with fractures of small and medium bones (radial, ulnar, fibula) a smaller diameter wire is used, for which a smaller perforation hole in the bone is required. For patients with fractures of large bone segments (proximal femur, humerus), to obtain stable osteosynthesis with sufficient deformation properties, it is necessary to choose a wire with a diameter of 2.0, 2.5, and even 3.0 mm.

The external diameter of the turns of the fixer depends on the width of the medullary canal into which the structure is screwed. The human anatomy is such that in small tubular bones (hand, foot), the medullary canal can be from 1-2 mm, in the humerus, the medullary canal has a diameter of 8 mm to 12 mm. In larger tubular bones (femur, tibia), respectively, up to 14 mm. In this regard, for the treatment of fractures of the humerus, it is assumed the industrial manufacture of structures with external diameters of 4; 6; 8; 10; 12 mm. The selection of the necessary fixator is carried out in the preoperative period in a known manner (this is how joint prostheses, pins, etc. are selected) according to radiological images of a healthy limb using transparent spring templates. The total length L of the coil part of the retainer is selected for each individual patient, taking into account the fracture site. Adjustment of the real length of the latch is carried out directly during the operation, an extra portion of the distal end of the latch bites off. The cylindrical part of the clamp consists of 10-12 turns, and the conical part of the clamp consists of 2-3 turns.

As our studies have shown, to achieve angular stability, it is necessary that 2/3 of the length of the retainer is located in the medullary canal, and 1/3 of the length in the spongy substance of the head. Only under conditions 2/3 + 1/3, stable osteosynthesis is achieved, which will allow patients to start rehabilitation measures 2-3 days after surgery without the risk of displacement of bone fragments. Thus, the total length L should provide the ability to introduce 1/3 of the retainer into the bone head.

In FIG. 2-4 show specific examples of insertion of a fixative.

An intramedullary fixative is also used for surgical fracture prophylaxis, in the diagnosis of osteoporosis (data after densitometry or the presence of a single marker fracture in the anamnesis) with a high risk of fractures.

For the prevention of a fracture of the distal metaepiphysis of the radius, a fixator is used with an outer diameter of 6-8 mm, a length of not more than 100 mm, through perforation in the styloid process of the radius. For the prevention of a fracture of the femoral neck, a fixator is used with an outer diameter of 12-14 mm and a length of not more than 150 mm through perforation in the underwent section of the femur. For the proximal humerus, a latch is required with an outer diameter of 8-10-12 mm, a length of not more than 165 mm. Such bioactive reinforcement will restore the bone structure and minimize the risks of low-energy fractures that occur in the elderly.

Bioactive intramedullary fixative provides not only a local effect on the affected skeleton segment, but also a general effect on the entire musculoskeletal system. Thus, the shape and material of the fixative ensures stabilization of bone fragments during fracture or reinforcement of the bone in areas of high risk of fracture against osteoporosis, and the bioactive layers mentioned above restore the bone mineral density and its elasticity due to collagen restoration.

Claims (1)

An intramedullary fixator for the surgical treatment of periarticular fractures of the tubular bone, made in the form of a needle bent in the form of a coiled coil spring, the turns of which are parallel to each other and are located at an angle of 30-50 °, characterized in that the three distal turns are made in the form of a conical spring, which descends to the diameter of the spoke, and the final part of the proximal turn ends with a spoke having a rectangular section, the length of which is 30-35 mm, while the body of the spoke contains an intermediate hardened layer, inside a transverse dielectric bioinert layer, an external dielectric bioactive layer consisting of two layers, the first layer being made in the form of a calcium phosphate coating, and the second layer being made in the form of a coating with hyaluronic acid.

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