Spatial Deformation of Osteosynthesis Systems. Message 1. Criteria of Functional Reliability.

Based on experimental studies, an analytical method is proposed for assessing the functional reliability of osteosynthesis systems. As criteria for the rigidity of osteosynthesis systems, displacements and mutual rotations of parts of bone fractures with fixation tools were used. The characteristics of the “bone with a fracture - fixation system”, necessary for calculations, determined experimentally from individual loads by compression, bending, and torsion of bone samples with simulated fractures and fixation tools. The characteristics of the plates for fixation of tibial fractures are determined, the level of allowable loads is calculated according to the combined action of compression, bending and torsion, and the areas of valid loads are determined. The proposed criteria for functional reliability make it possible, using simple tests and analytical calculations, to determine permissible load levels that do not lead to the occurrence of dangerous movements in the fracture area