The paper presents the processing technology that could be used in order to obtain a new design of a stem component for a hip prosthesis type lattice beam. This new design was made based on the analysis of the currently successful stems used in clinical practice and on different biomechanical and biomaterials criteria. Metallic biomaterials used for manufacturing different components for hip prosthesis are usually austenitic stainless steel type 316L, Co-Cr alloy and titanium based alloy. In our study, considering the specific design of the stem, stainless steel type 316L with the nominal compositions (%weight): C <0.03, Cr 17, Ni 14.5, Mo 2.7, Mn <2.0, Si <1.0, P <0.025, S <0.010, Fe balance is used. Different mechanical processing techniques were used in order to obtain the experimental prototype. According to the well-known limitation of the stainless steel type 316L as biomaterial for long term implants, we propose for the new stem component to use a TiN coating obtained using magnetron sputtering technique. The cytotoxicity studies were performed using a CCl 81 (VERO) stabilized cellular line, in order to analyse the biocompatibility properties. The samples were examined for the development of the cellular culture, in order to compare the results obtained using direct contact method. From the point of view of these tests, it was not observed an essential modification of cells and the cellular morphology is not affected by the presence of the TiN coated metallic samples. In the conclusion, the new geometry proposed for a stem component of cemented hip prosthesis could be made using different mechanical processing techniques and appears to be a potential solution in order to solve the problems related to the stability of the total hip prosthesis, with improved biocompatibility properties due to the TiN coatings.
Comparison of Vacuum Sintered and Selective Laser Melted Steel AISI 316L