Изучение возможностей углеродного материала в паре трения эндопротеза тазобедренного сустава при помощи математического моделирования и стендовых испытаний

Abstract

INTRODUCTION: One of the most effective methods of surgical treatment of late-stage coxarthrosis is total hip replacement. However, the steady increase in the number of primary endoprosthetics results in the increase of revision surgeries. Our proposed solution to use carbon material in bearings will decrease the number of revision surgeries due to component wear, and may also significantly reduce the risk of aseptic loosening. AIM: To compare stress and torque of the head and liner structures with bearings made of carbositall with diameters of 28 mm and 38 mm using mathematical modeling and to compare the volume wear of bearings made of ceramics and carbositall using bench tests. MATERIALS AND METHODS: Mathematical modeling was used to assess the stresses in the proposed design. The mathematical model was created by software-based methods in ANSYS 5.7 environment. Structures with diameters of 28 mm and 38 mm were studied. A physical model of a bearing made of carbositall was made for bench testing. In accordance with requirements of GOST 31621-2012, a torque test of a carbositall bearing was performed. In accordance with GOST R ISO 14242-3-2013, a study of volume wear of bearings made of ceramics and carbositall was performed. RESULTS: Mathematical modeling of a bearing made of carbositall with a size of 38 mm in comparison with a bearing with a diameter of 28 mm showed a decrease in intensity of compressive and tensile stresses with a natural increase in the safety factor for components made of carbositall. Based on the results of the torque test of bearing for hip arthroplasty, the torque was 1.1 Nm. This indicator is 26.6% lower than the maximum permissible according to GOST 1.5 Nm. The torque index was 1.10 Nm. As a result of a comparative test for wear of bearing made of ceramic and carbositall, the mass loss of the ceramic head was 0.009 g, the mass loss of the ceramic liner was 0.013 g. The head made of carbositall lost 0.006 g, while the liner lost 0.009 g. In total, the mass loss of the carbon bearing is 31.8% less than that of the ceramic one. CONCLUSION: A large-diameter bearing showed the best strength characteristics of the carbon part of the structure, however, the strength limit of the titanium sleeve decreased. The torque of the carbon bearing was 1.1 Nm, which is 26.6% lower than the maximum permissible index, and the volume wear of the bearing made of carbositall is 31.8% less than the volume wear of the bearing made of ceramics.