Introduction The search for materials for bone defect filling that would provide a release of antibiotics in therapeutic levels over a long period is a pressing issue in the treatment of patients with osteomyelitis.The purpose of the work was to compare the kinetics of antibiotic release from materials based on polyurethane polymers for filling post-osteomyelitic bone defects.Materials and methods A comparative in vitro analysis of the kinetic release of cefotaxime, vancomycin, and meropenem from two materials was performed: one was based on polyurethane polymers (RK series) and the other on polymethyl methacrylate (PMMA series). In each series, antibiotics were added to the original materials in three proportions: polymer/ antibiotic — 10:1 (group 1); 10:0.5 (group 2), and 10:0.25 (group 3). The samples were incubated in 10 ml of saline at 37 °C. The incubation solution was changed daily during the first week, and then once a week. Six samples were incubated in each group.Results It was revealed that the volume of eluted cefotaxime in the PMMA series was higher than in the RK series for all antibiotic concentrations. In turn, for vancomycin and meropenem, it was observed only for group 1 samples. For groups 0.5 and 0.25, a larger volume of released antibiotics was noted in the RK series than in the PMMA series. It was found that in the RK series, the release of vancomycin and cefotaxime in an effective (therapeutic) concentration was more prolonged. In the RK series, there was prolonged release of effective concentrations but in a smaller volume of released antibiotic than in the PMMA series.Discussion Each material showed its own antibiotic elution profile and each of them may have its own indications. The RK-based material has advantages in terms of the duration of antibiotic elution in therapeutic doses.Conclusion The release of the studied antibiotics in effective concentrations from the material based on polyurethane polymers is longer than from the PMMA-based material.

Introduction Increasing the integration of transcutaneous implants is an important goal for their application in clinical practice.The purpose of the work was to evaluate the osseointegration of transcutaneous titanium implants with calcium-phosphate coating containing zinc ions.Materials and methods The studies were performed on 12 male rabbits, who underwent implantation of an original implant into the tibial stump. After implantation, a compression device was installed on the bone, maintaining a load of 3.5 N for 5 weeks. Duration of observation was 26 weeks. The animals were divided into two groups: a control group (n = 6) with an implant without coating and an experimental group (n = 6) with a zinc-substituted calcium-phosphate coated implant.Results The implant fell out in one case in animals from the control group; no cases of implant loss were noted in the experimental group. It was revealed that the weight concentration of Ca and P in all zones of the bone-implant block of the animals in the experimental group significantly exceeded similar indicators in the control group. In the control group, long-term persistence of high levels of C-reactive protein was noted, which was not observed in the experimental group.Discussion This series of studies has shown that an implant with a zinc-modified calcium-phosphate coating exhibited a more effective integration, in contrast to an uncoated product. The absence of serious adverse reactions to the tested products indicates acceptable tolerability and safety of its use.Conclusion The implants with a zinc-modified calcium-phosphate coating showed signs of more effective osseointegration compared to the product without additional coating.

Introduction It has been shown that titanium implants with a structured surface provide an increased rate of osseointegration what makes their application quite promising.The purpose of this work was to conduct a comparative evaluation of the efficiency of osseointegration of new percutaneous implants for prosthetics made of ultrafine-grained Ti Grade 4 alloy.Materials and methods The study was carried out on 12 male rabbits of the Soviet Chinchilla breed. Six rabbits of the control group had implants made of Ti6Al4V powder using selective laser sintering technology that were osseointegrated into the tibia, 6 rabbits of the experimental group had implants made of Ti Grade 4 by equal channel angular pressing. The formation of the "bone-implant" block was examined 26 weeks after the implantation.Results Histologically, after 26 weeks of the experiment, porous changes, enlargement of the Haversian canals, and pronounced osteoclastic resorption were not detected in the animals of the experimental group throughout the stump in the compact plate. Around the implant, a bony case repeating the bone shape was formed, represented by lamellar bone tissue. Using X-ray electron probe microanalysis, it was found that in the substrate formed on the surface of the implant in rabbits of the experimental group, there was significantly more calcium in all areas over the implant relative to the animals of the control group. In the control group, relative to the experimental group, an increased level of C-reactive protein in blood serum was retained longer. Complications and significant clinical and laboratory abnormalities were not found in both groups during the entire experiment.Discussion Our data are consistent with the results of other experimental studies, which unambiguously noted that titanium implants with a structured surface show increased osseointegration characteristics in comparative studies relative to implants without modification of the structure of the material of the threaded surface. The absence of complications and undesirable reactions of the animal organism also indicates the acceptable safety of the tested products.Conclusion Osseointegration of a percutaneous implant that has a mixed nanocrystalline and ultrafine-grained structure was more effective than the reference implant. This makes the use of such implant promising for solving clinical problems in prosthetics.

Introducrion Repair of the affected articular surface still remains an unsolved problem.The purpose of this study was to assess the efficacy of a biodegradable polycaprolactone implant coated with hydroxyapatite on the healing of an osteochondral defect of the femoral condyle in rats.Materials and methods An osteochondral defect of the medial femoral condyle was modeled in 76 Wistar rats divided into 2 groups. In the experimental group, the defect was replaced with a biodegradable polycaprolactone membrane coated with hydroxyapatite. In the control group, the defect remained untreated. The results were assessed within a year.Results In the experimental group, the animals had a significantly better range of motion at all stages of the experiment than the control animals. The implant ensured the integrity and congruence of the articular surface. On day 180, a newly formed area of the articular surface of the organotypic structure was observed in the defect. Biomechanical properties of the repaied zone restored after 60 days while in the control one they remained lower by 27-29 %.Discussion Filling the defect with an elastic implant made of polyprolactone with hydroxyapatite provided early functional load on the joint. The structure of the implant, simulating the extracellular matrix, promoted the growth, proliferation and directed differentiation of cells in the area of the osteochondral defect. The moderate rate of biodegradability of the material provided gradual replacement of the implant with organ-specific tissues.Conclusion A biodegradable polycaprolactone implant impregnated with hydroxyapatite particles might be effective for experimental osteochondral defect repair.