The aim: To analyse long-term results of treating patients with open fractures of low-leg bones within a specific time period and to describe concomitant problems. Materials and methods: A retrospective study was carried out to evaluate the results of the final treatment of patients after one year and after five years. Patients were divided into two groups. Group I included 47 (61.84%) patients for whom the treatment method was changed from external fixation to internal fixation. Group II included 29 (38.16%) patients for whom the final treatment of an open fracture was performed with an external fixation device without changing the method. The study exclusion criteria were patients under 18 years old and patients with gunshot fractures of the lower leg bones. Results: Patient treatment included initial surgical debridement and fracture stabilization with external fixation devices. In all patients, wound healing occurred within 30 days (on average, 24 ± 4.5 days). When evaluating the treatment of patients in group I, 32 (68.09%) of them underwent a one-stage removal of an external fixation device and osteosynthesis of fragments during the first 7-10 days. In 3 (20.0%) patients, osteosynthesis was performed with an intramedullary locking nail, in 12 (80.0%) patients – with a plate. The decision to change the fixation method was made taking into account clinical and laboratory parameters. It is noted that the treatment of patients with type III open fractures of the lower leg bones according to the Gustilo-Andersen classification, provided that the method of external fixation is replaced with an internal one, gives better results compared to osteosynthesis with external fixation devices. Conclusions: Treatment of patients with high-energy injuries of the lower leg bones is a long-term process. It is possible to improve the therapy efficiency by changing the fixation method from external to internal one. In this regard, the main evaluative characteristics are such indicators as uncomplicated wound healing combined with the absence of laboratory and clinical signs of inflammation.

The aim of the research is to determine “to and fro” venous flap blood circulation perfusion ability and flap size survival. Materials and methods: “To and fro” blood circulation mathematical model based on the theory of compressed liquid flow thought the porous medium. Result: Designed mathematical model allows to calculate the viable flap size that depends on pedicle vessel radius, the blood pressure gradient, the blood viscosity, the elastic tissue capacity, the pulse frequency, vessels flap topography and surgical pedicle flap technique. Viable flap width may extent up to 4-6 cm. Conclusions: Only thin skin or fascial flaps, were through venous pedicle with a lot of side branches located under the flap surface and along central flap axis may survive with “to and fro” blood circulation.