Studies on design of customized orthopedic endoprostheses of titanium alloy manufactured by SLM

This paper presents studies on the design of prostheses manufactured by selective laser melting (SLM) of porous Ti alloys. The results are materialized by a new design and manufacturing strategy of customized orthopedic endoprostheses. The strategy is presented in a case study. The design methodology consists in processing, editing, analyzing, and performing measurements with the Materialise's Interactive Medical Image Control System (MIMICS) software in order to extract and develop the 3-D model from specific computed tomography (CT) files. The finite element analysis (FEA) was used in order to verify the distribution of the cortical bone tissue of a femur and to evaluate the prosthesis by simulating normal and atypical daily activities. The contact surfaces and the elements of the endoprosthesis were established taking into account the distribution of the von Mises equivalent stress in the section carrying the highest loads. It was elaborated a strategy that allows reproducing anatomic bone shapes by using B,zier curves and obtaining parameterized 3-D models. After determining the ideal shape, the prosthesis to be fabricated by SLM was designed and analyzed. An original item of the research is the design of a multistructural endoprosthesis consisting in three elements with different structural proprieties. The proposed prosthesis model is a perfectible solution, the research being focused exclusively on the considered case. By studying the distribution of bone structures, their shapes, and dimensions, new prostheses can be obtained following the steps of the strategy elaborated in this study.