Shcherbakov D. Clinical and experimental justification for the application of the improved radial head implant mode

The thesis is devoted to the clinical and experimental justification for the application of the improved radial head (RH) implant model. On the basis reasoning from the study of the radial head and neck MRI anthropometric data, the main optimal standard sizes of the new improved uncemented modular bipolar RH implant have been developed. Due to the development of a new mathematical three- dimensional model of the elbow joint and the computational experiment, it has been proved that the head of the radial bone does not have a strictly fixed radius of displacement relative to the capitellum with different angles of pronation-supination. Compliance of the articular surfaces in a healthy elbow joint is maintained by the complex configuration of the radial head and the capitellum, which is the basis for the biomechanical justification for the new improved design of the bipolar modular RH implant. On the basis of biomechanical three-dimensional simulation and mathematical experiment, it has been proved that the nature of the bipolar "floating head" implants displacement into a stable position for all the calculated values of the rotation angle in the event of pronation-supination reveals the tendency towards reducing the distance between the radial bone contact surfaces in relation to both humerus and elbow bone, as well as manifests the decrease by 45-60% in the maximum strain values in all of the considered cases. On the basis of biomechanical and anthropometric studies of the radial head and neck, a new improved design of the modular bipolar RH implant has been developed, which allows to ensure its reliable initial and long-term fixation in the bone, reduce the strain on the articular surface of the capitellum in comparison with monoblock implants; restore the elbow joint stability after the fracture - dislocation, as well as improve the functional results of the RH injuries treatment.