RADIAL HEAD ARTHROPLASTY WITH THE BIPOLAR IMPLANTS

Abstract

The aim: Of the research is to study of the stress distribution in the “bone-implant” system for various cases of elbow flexion and semipronation in the event of the radial head arthroplasty with the developed bipolar radial head (RH) implant and the bipolar KPS endoprosthesis. Materials and methods: We developed a metal-metal bearing bipolar RH endoprosthesis providing an uncemented fixation due to a special porous coating and stem design. Using Solid Works software, we developed a geometrical model of the elbow joint with cartilaginous surfaces. Then, to refine the parameters of the finite-element model, calculation and visualization we transferred the model to the ANSYS complex. Results: The developed bipolar RH endoprosthesis with metal-metal bearing is a stiffer construction compared to the KPS endoprosthesis. However, the displacement fields in the joint and the value of arising maximum strains in the “bone-implant” system with the RH endoprosthesis have a smaller deviation from the strains arising in the healthy elbow joint than those in the “bone-implant” system with the KPS endoprosthesis. Conclusions: The developed bipolar RH endoprosthesis does not cause any critical impacts on the joint surfaces and ligamentous apparatus of the elbow joint. All the elements of the developed bipolar RH endoprosthesis satisfy the requirements of an operative structure strength and stiffness. Strain fields arising in the bipolar RH endoprosthesis have a smaller deviation from the strains in the healthy joint in comparison with those occurring in the “bone-implant” system with the KPS endoprosthesis.