A lot of research was conducted on the use of various biomaterials in orthopedic surgery. Our study investigated the effects of nanostructured calcium–phosphate coating on metallic implants introduced into the bone marrow canal. Stainless steel or titanium 2-mm wires (groups 1 and 2, respectively), and hydroxyapatite-coated stainless steel or titanium wires of the same diameter (groups 3 and 4, respectively) were introduced into the tibial bone marrow canal of 20 dogs (each group = 5 dogs). Hydroxyapatite coating was deposited on the wires with the method of microarc oxidation. Light microscopy to study histological diaphyseal transverse sections, scanning electron microscopy to study the bone marrow area around the implant and an X-ray electron probe analyzer to study the content of calcium and phosphorus were used to investigate bioactivity and osteointegration after a four weeks period. Osteointegration was also assessed by measuring wires’ pull-off strength with a sensor dynamometer. Bone formation was observed round the wires in the bone marrow canal in all the groups. Its intensity depended upon the features of wire surfaces and implant materials. Maximum percentage volume of trabecular bone was present in the bone marrow canals of group 4 dogs that corresponded to a mean of 27.1 ± 0.14%, while it was only 6.7% in group 1. The coating in groups 3 and 4 provided better bioactivity and osteointegration. Hydroxyapatite-coated titanium wires showed the highest degree of bone formation around them and greater pull-off strength. Nanostructured hydroxyapatite coating of metallic wires induces an expressed bone formation and provides osteointegration. Hydroxyapatite-coated wires could be used along with external fixation for bone repair enhancement in diaphyseal fractures, management of osteogenesis imperfecta and correction of bone deformities in phosphate diabetes.

Previously, 3D-printed bone grafts made of titanium alloy with bioactive coating has shown great potential for the restoration of bone defects. Implanted into a medullary canal titanium graft with cellular structure demonstrated stimulation of the reparative osteogenesis and successful osseointegration of the graft into a single bone-implant block. The purpose of this study was to investigate osseointegration of a 3D-printed degradable polymeric implant with cellular structure as preclinical testing of a new technique for bone defect restoration. During an experimental study in sheep, a 20 mm-long segmental tibial defect was filled with an original cylindrical implant with cellular structure made of polycaprolactone coated with hydroxyapatite. X-ray radiographs demonstrated reparative bone regeneration from the periosteum lying on the periphery of cylindrical implant to its center in a week after the surgery. Cellular structure of the implant was fully filled with newly-formed bone tissue on the 4th week after the surgery. The bone tissue regeneration from the proximal and distal bone fragments was evident on 3rd week. This provides insight into the use of bioactive degradable implants for the restoration of segmental bone defects. Degradable implant with bioactive coating implanted into a long bone segmental defect provides stimulation of reparative osteogenesis and osseointegration into the single implant-bone block.

Purpose. We studied osteogenesis and morphofunctional features of the anterior tibial muscle using 3-mm high-frequency automated lengthening with the Ilizarov apparatus alone and in combination with intramedullary nailing. Material and Methods. Tibia was lengthened with a round-the-clock automated distractor at a 3-mm daily rate for 10 days in 16 mongrel dogs. In group 1 (n = 8), a 1.8-mm intramedullary titanium wire coated with hydroxyapatite was introduced into the tibial canal followed by Ilizarov frame mounting and transverse osteotomy of the diaphysis. Distraction mode was 0.025 mm x 120 increments a day. In group 2 (n = 8), distraction mode was the same but nailing was not used. Bone formation and the anterior tibial muscle were studied at two time points: (1) upon distraction completion; (2) three months after the apparatus removal. Bone formation was studied radiographically. Muscle preparations were examined histologically and stereomicroscopically. Results. There was a threefold reduction in the distraction time in both groups. Consolidation took 13.83±4.02 days in group 1 and 33.7±2.4 days in group 2. Muscle macropreparations of the experimental limb in group 1 at study time points did not show significant differences from intact tissues. Muscle histostructure in both groups was characterized by activation of angiogenesis and myohistogenesis, but the volumetric density of microvessels in the lengthening phase was three times higher in group 1. Conclusion. Combined technology significantly reduces the total lengthening procedure and does not compromise limb functions. Intramedullary HA-coated wires promote faster bone formation. The muscle was able to exhibit structural adaptation and plasticity of a restitution type.

Background: Intramedullary transphyseal elastic osteosynthesis is used in children for the diseases accompanied by the reduced strength properties of bone tissue, and primarily for osteogenesis imperfecta. Objective: The purpose of the experimental study was to investigate tibial growth under the conditions of transphyseal counter-directed insertion of elastic rods without bone integrity breaking, under transverse fracture modeling, as well as under combining transphyseal reinforcement and subperiosteal positioning the titanium mesh with the elastic rods intervolved in it. Methods: Non-randomized controlled trial was performed. Three series of experiments performed in 18 puppies. Counter-directed transphyseal reinforcement of tibia performed in Series I,, transphyseal reinforcement combined with transverse osteotomy of leg bones — in Series II, transphyseal elastic osteosynthesis and subperiosteal positioning the titanium nickelide mesh with intervolved in it elastic rods during transverse leg bone osteotomy performed in Series III. Results: Transphyseal reinforcement resulted in growth retardation of the operated tibia. The loss of residual growth was 3.8 mm (p =0.078) in series I; 7.8 mm (p =0.032) — in series II; 7.7 mm (p =0.042) — in series III. Eccentric insertion of transphyseal rods formed an angular deformity (mean value 7°; p =0.023) of the distal tibial epiphysis in the process of residual growth. Periosteal and endosteal reactions contributed to enlargement of diaphyseal diameter of 3.9 mm (series II; p =0.037) and 3.8 mm (series III; p =0.041). Any difference of diameter between operated and intact tibia was not observed in series I. Conclusion: Intramedullary transphyseal reinforcement retards longitudinal bone growth. The positioning of the telescopic systems should be as close as possible to the center of growth plates in order to prevent angular deformities. Subperiosteal reinforcement doesn’t retard consolidation of fragments, and it can be combined with intramedullary transphyseal osteosynthesis

BACKGROUND: Gram-negative bacteria, specifically P. aeruginosa, Acinetobacter spp., Klebsiella spp., and Enterobacter spp., can cause osteomyelitis. Two-stage treatment according to the Masquelet technique is considered effective; however, single-stage surgical treatment options are also being investigated. Submerged implants with bioactive antimicrobial calcium phosphate coating may prevent infectious complications, reduce the incidence of osteomyelitis relapses, and accelerate osteogenesis. AIM: To assess bactericidal properties of experimental titanium implants with antimicrobial calcium phosphate coating against gram-negative bacteria. MATERIALS AND METHODS: A single-center, continuous, prospective, open-label experimental in vitro study was performed. The disk diffusion test was used. BT6 titanium disks with calcium phosphate coating, impregnated with amikacin, cefepime, and cefotaxime (2.5/5.0/7.5 µg), were tested. Reference cultures: archival strains of Pseudomonas aeruginosa (АТСС 27853), Acinetobacter baumannii (АТСС 19606), and Klebsiella pneumoniae (АТСС 700603). The results were assessed by the inhibition zone diameter around a disk. RESULTS: The study found that impregnating a bioactive metal base with amikacin and cefotaxime at a dose of ≥2.5 µg or cefepime at a dose of ≥7.5 µg results in bactericidal activity against Klebsiella pneumoniae. Amikacin at a dose of ≥5 µg and cefepime at a dose of ≥7.5 µg provide bactericidal activity against Pseudomonas aeruginosa. Antibiotic doses used in the study had no bactericidal effect against Acinetobacter baumannii. The bactericidal effect was only investigated in relation to archival gram-negative bacteria strains, which is a limitation of this study. Using clinical strains may yield different results. CONCLUSION: Commonly used antibiotics may provide bactericidal properties of the surface of submerged implants designed for traumatic and orthopedic surgery, notably against gram-negative bacteria. However, the efficacy of implants depends on the selected antibiotic and its concentration.