There was clinically and experimentally substantiated the influence on reparative osteogenesis of osteo-substitution by calcium-phosphate ceramics with various physicochemical properties, including silicon alloyed, which is new in solving the problem of optimizing the consolidation of fragmentary fractures of long tubular bones in animals. It was proved by clinical-radiological, macro- and histo-morphological way and on the basis of hematological, biochemical and molecular-biological criteria for the assessment of reparative osteogenesis, that in rabbits and dogs the calcium-phosphate ceramics within the hydroxyapatite (72%), β-tricalcium phosphate (28%) and silicon (1.3 wt.%) with adsorption activity of more than 220 mg/g, implanted into defects of compact or spongy bone tissue, exhibits high osteoconductive, osteo-integrative and osteo-inductive properties with moderate biodegradation of osteo-substituting material, due to which in case of fragmentary fractures of tubular bones in dogs their consolidation time decreases by 1.5 times (p<0.001).
Thus, the clinical and radiological evaluation of fragmentary fractures of long tubular bones in dogs showed that their largest percentage include the leg - 38.5%, slightly less the forearm - 26.9%, femoral bone - 19.2% and the least humerus - 15.4%. They are mostly localized in the diaphysis area - 46.2%, slightly less in metaphysis area - 42.3%, while the pineal gland - only 11.5%.
For the first time, according to the international classification AО/ASIF principles, it was established that the largest part of fragmentary fractures of long tubular bones - 50% - belongs to type C, 46.2% - to type B and the smallest - 3.8% - belongs to the simplest type A. Within the subgroups, the largest part - 19.2% - was for subgroups B1, B2 and C2, slightly smaller part - 15.4% – for C1 and C3 subgroups and very small part – 7.8 and 3.8% - for B3 and A2 subgroups, respectively. This is the basis for a more rational choice of methods and means of osteosynthesis using osteo-substitute materials to optimize reparative osteogenesis.
For the first time in veterinary orthopedics there was performed clinical and experimental monitoring of a number of calcium-phosphate ceramics with different physicochemical characteristics according to the degree of their osteoconductive, osteo-integrational and osteo-inductive properties for the purpose of osteo-substitution of bone defects in animals. The following calcium phosphate materials were studied: biphasic granules of hydroxyapatite (70%) and α-tricalcium phosphate (30%) with adsorption activity of 118.7 mg/g (GTα-500); three-phase granules of hydroxyapatite (55%), α-tricalcium phosphate (30%) and β-tricalcium phosphate (15%) with adsorption activity of 220.5 mg/g (GTα+β-700); two-phase granules of hydroxyapatite (70%) and β-tricalcium phosphate (30%), doped with silicon (1.3 wt.%) with adsorption activity of 117.9 mg/g (GT1Kg-2); washed two-phase granules, hydroxyapatite (72%) and β-tricalcium phosphate (28%), doped with silicon (1.3 wt.%) with adsorption activity of 229.1 mg/g (GTlKg-700).
Radiologically, the calcium-phosphate ceramics osteo-substitution was characterized, while comparing with bone defects healing under the blood clot, by moderate periosteal and endo-osteal reactions only within the bone injury, by dynamic increase of osteosclerosis phenomenon as a sign of osteogenic processes, which intensity was higher than the use of ceramics alloyed with silicon with their higher dynamic biodegradation.
At the same time, macromorphologically, the bone regenerates of compact bone tissue on the 21st day in the control group were loose, crater-shaped with massive periosteal growths, when using GTα-500 - bone defects were completely filled with a large number of ceramic granules, firmly connected to the regenerator, during moderate periosteal reaction, with GTα+β-700 – the material together with the newly formed bone tissue formed a monolith and fully integrated with the maternal bone, with GTlKg-2 – callus was somewhat isolated and was clearly above the formed bone defect, and with GTlKg-700 – it granules were barely visible in the bone regenerate monolith, extremely integrated into the maternal bone tissue without periosteal growths. The macromorphological picture of bone regenerates in spongy bone tissue was similar.
According to the histo-morphological score, it was found that reparative osteogenesis in compact bone in rabbits during osteo-substitution with GTα-500 or GTα+β-700 was accelerated by 1.4 times (p<0.01), with GTlKg-2 – by 1.5 times (p<0.001), and with GTlKg-700 - by 1.6 times (p<0.001), in spongy – by 1.4-1.5 times (p<0.001), by 1.8 and by 2.0 (p<0.001), respectively. At the same time, the histo-morphological evaluation of GTlKg-700 was significantly higher by 1.1 times than in the groups with unalloyed ceramics.
