The condition of bone tissue in experimental osteoporosis with a fracture of the femur diaphysis with the use of various titanium implants
Objective. The analysis of the effectiveness of titanium implants based on the BT-6 alloy with calcium-phosphate coating at fractures of the femur on the background of systemic osteoporosis in the experiment was carried out. Methods. The work was performed on 27 rats of Wistar males, in 24 of which, divided into four groups, glucocorticoid-induced osteoporosis was reproduced, followed by modeling of the closed fracture of the diaphyseal part of the femur. In two groups of animals, fixation of fragments was performed by the method of closed intramedullary retrograde osteosynthesis using uncoated titanium implants and coated with hydroxyapatite. Comparison groups were formed by animals, the healing of fractures in which passed without the use of implants, and animals with osteoporosis without fracture. The control group included three healthy animals. On the 14<sup>th</sup>, 30<sup>th</sup> and 60<sup>th</sup> day of the experiment, a histological and morphometric assessment of the bone tissue condition was performed. Results. The use of implants coated with hydroxyapatite in osteosynthesis in conditions of osteoporosis led to an earlier regeneration of bone tissue. Thus, the thickness of the cortical bone and thickness of trabeculae were significantly higher in rats with osteosynthesis covered with implants. On the 14<sup>th</sup> day of the experiment, the coarse-fibrous connective tissue appeared in the fracture zone of the designated group of animals, which on the 30<sup>th</sup> day began to transform into the lamellar bone, and on the 60<sup>th</sup> day the bone loss was completely restored. If an uncovered implant was placed on the 60<sup>th</sup> day, foci of imperfect osteogenesis and osteoid with a low degree of mineralization were preserved in the fracture zone, and in animals with which the implant was not installed, the fibreticular tissue was preserved. Conclusions. The dynamics of the bone tissue condition in fractures in rats with the model of osteoporosis testifies to the acceleration of the regeneration process due to the use of titanium implants coated with hydroxyapatite. So we may regard the use of such devices as a promising way to improve the results of fracture treatment in conditions of systemic osteoporosis.