Study of the stress distribution in the model of the tibia with its fracture in the lower third with different options of osteosynthesis under conditions of increasing bending load

Abstract

Fractures of the lower leg bones make up a significant part of the traumatism structure. In the Kharkiv region in the period 2015-2018, lower leg fractures accounted for 19% of other traumatic injuries. More than 50% of complications after treatment of these fractures cause disability. The goal was to conduct a comparative analysis of the stress-strain state of models of the tibia with its fracture in the lower third with different options of osteosynthesis under the influence of bending load depending on the patient's weight. A tibial fracture in the lower third and three types of osteosynthesis were simulated using an external fixation device (EFD), a periosteal plate and an intramedullary rod. The models were loaded for bending with a force of 700 N, and 1200 N. Osteosynthesis with EFD and an intramedullary rod decreased stress values in the fracture zone below the level of indicators for an intact bone. The periosteal plate shows the highest stresses in the fracture zone and the distal tibial part. During osteosynthesis of the EFD, the highest stress level is determined in the proximal part. The periosteal plate will experience the most significant stresses than other metal structures. When using an intramedullary rod, the highest stress level on the fixing screws is determined, the minimum – when using EFD. When using a periosteal plate, the stress level in the fracture zone and the plate is equal to the strength limits of both tubular bones and stainless steel so that early loads can cause a fracture of the plates and non-union of tibial fragments. Osteosynthesis using EFD and an intramedullary rod ensures the lowest level of tension in the fracture zone.