Download bone reparative regeneration around titanium implants after the low

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BONE REPARATIVE REGENERATION AROUND TITANIUM IMPLANTS AFTER
THE LOW-INTENSITY PULSED ULTRASOUND EFFECT
Malyshkina S.V.,
Makolinets V.I.,
Vishnyakova I.V.,
Nikolchenko O.A.,
Grashchenkova T.N.
Background. Different fixing systems are widely used in the reparative surgery of the
bone and joint injuries. The problem considering their prolonged functioning and
osteointegration into the bone is still urgent. Different methods of the osteoreparation
optimization are used, the ultrasound in particular, for the purpose of the metal implants and
endoprostheses aseptic instability prophylaxis. Nevertheless there exist a lot of contradictory
points of view in the research of the bone remodeling particularities when using the titanium
implants under the condition of ultrasound exposure.
The aim of the work is to research in the experiment on rats the structural organization of
the femurs with the titanium implants under the conditions of the impulse ultrasound exposure
with the 0.4 W/cm2 fluctuation intensity applied beginning with the third day after the surgery.
Materials and methods. The experiments were carried out on 30 white adult male-rats.
The cylindrical titanium sample (height 3.0 mm, diameter 2 mm) was implanted into animals’
distal femur metaphysis. The rats were surged under the general anesthesia (aminazine 10 mg/kg
and ketamine 50 mg/kg, intramuscularly). The rats were subdivided into two groups in 3 days
after the implantation: experimental (15 rats whose bone area with the implant was exposed to
the impulse ultrasound) and control (15 rats without ultrasound exposure). The ultrasound
manipulation was being carried out with the UZT-1.01 ultrasound machine for 5 minutes (once a
day) during 10 days. The impulse ultrasound with the oscillation frequency of 0.88 MHz and
oscillation intensity of 0.4 W/cm2 was used. The animals were euthanized in the experiment in 7,
14, 45 days after the surgery. The experiments on animals were carried out satisfying the modern
bioethics requirements. The material for the research was the femur zones with the implants
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which were removed after the decalcification. The morphological, morphometrical and statistical
methods were used. Histology sections samples were stained with the Weigert's hematoxylin and
eosin.
Results. The ultrasound usage does not damage the osteoreparative process. It takes place
in the well-known stages with the consecutive formation of the granular, fibroreticular and bone
tissues. However, the impulse ultrasound of the given mode accelerates the granular tissue
remodeling, that is shown by experimental animals’ granular tissue area which is less by 2.35
times, and the osteogenic differentiation of the cells in fibroreticular tissue, which is shown by
the osteoblasts significant density and a certain quantity of the newly formed bone trabeculae in
the implant perimeter on the 7th day, which is not evident in the animals of the control group.
There was determined the ultrasound optimizing effect on the osteoreparation and on the
damaged bone remodeling in the implantation zone at all the stages of the reparative
osteogenesis. A newly formed bone area in the implantation zone was at 2.3 times higher in the
experimental animals. The active osteoblastic surface indexes were also higher in the
experimental animals – 23.8±1.4 % (4.15±0.35 % in the control) and the osteoreparation index –
64.2 % (in the control – 52.8 %) on the 45th day after the implantation.
Conclusion. The ultrasound at the oscillation intensity of 0.4 W/cm2, applied on the 3rd
day after the titanium samples implantation, does not damage the stages of the osteoreparative
process. The ultrasound of the given mood activates the granulation tissue remodeling and the
osteogenic differentiation of cells in fibroreticular tissue at the early stages of the
osteoreparation, which stipulates future probably higher indexes of the newly formed bone area
in the implantation zone, the active osteoblastic surface and the osteointegration index in
comparison with the control.