Comparative biomechanical analysis of stresses of the «bone – implant» system in endoprosthetics of the radial head

Abstract

Objective: to conduct a comparative analysis of stress distribution in the bone and implant system for various cases of the elbow joint flexion and supination in the endoprosthesis of the radial head with a developed bipolar implant and bipolar endoprosthesis KPS. Methods: based on data provided by Zygote Media Group, Inc., a geometric model was created. In order to maximally repeat the biomechanics of the elbow joint in the model and the calculation schemes, cartilage surfaces and ligaments of the elbow joint are added. Using the SolidWorks and ANSYS software, a finite-element model was created, and then the calculation and visualization of the results were performed. In total, 45 geometric models were examined for 15 cases: for normal elbow joint, models with bipolar radial head endoprosthesis — developed and KPS. Results: it was established that all elements of the developed bipolar radial head endoprosthesis meet the requirements of durability and toughness of the working structure. The values of stress and strains are compared with the values obtained for a model in a healthy elbow joint. In the «bone – implant» system, under the conditions of the radial head endoprosthesis, the developed bipolar implant and endoprosthesis KPS did not reveal significant differences in stress and strain fields in implants and in the structures of the elbow joint. The deformation fields that arise in the developed bipolar radial head endoprosthesis radial head had a smaller deviation from deformations of the normal joint compared to the KPS endoprosthesis. Conclusions: the developed bipolar radial head endoprosthesis with a pair of friction «metal – metal» does not exert a critical influence on the articular surfaces and the connective device of the elbow joint.