Analysis of the stress-strain state of the tibial model in case of its fracture in the upper third with various types of osteosynthesis under increasing bending load

Abstract

Background. Currently, there is an increase in the lower limb fractures (47.3 %). More than 50 % of complications are related to the treatment of tibial fractures, which caused 27.9 % of disability. Goal: to conduct a comparative analysis of the stress-strain state of the tibial models with a fracture in the upper third with different options of osteosynthesis under bending load depending on the patient’s weight. Materials and methods. The model simulated a tibial fracture in the upper third and three types of osteosynthesis using an external fixation device (EFD), a bone plate and an intramedullary rod. The models were tested under the influence of a bending load of 700 and 1200 N. Results. Normally, the stress under bending load is maximal in the distal tibia. When using EFD, the maximum stress level is observed in the distal fragment of the tibia. During osteosynthesis with a bone plate, the stresses are maximal in the fracture zone. Osteosynthesis with an intramedullary rod provides the lowest stress level in the fracture zone. An increase in the load up to 1200 N leads to an elevation in the stress values in all elements of the model. Conclusions. Under bending loads, indicators of the stress level in the fracture zone and the metal structure were the worst when using a bone plate. Osteosynthesis with the help of EFD ensures the lowest level of stress in the fracture zone, it is also worth noting the lowest level of stress on the device itself. Quite low stress indicators in the fracture zone and in the proximal fragment of the tibia occur when using osteosynthesis with an intramedullary rod.