Topology optimization of the pelvic bone prosthesis under single leg stance

Pelvic reconstruction is required to restore the functional activity after an internal hemipelvectomy. The available pelvic prosthesis has several complications and long terms issues (such as stability, dislocations etc.) due to non inclusion of the basic mechanics. In this study, a structural optimization based pelvic design is presented for an efficient pelvic prosthesis by including the effect of muscles under single leg stance. The single leg stance loading condition is divided into four categories, (a) all muscles, (b) lower muscles, (c) upper muscles and (d) average value of the muscles for entire stance phase. Thereafter, topology optimization is used to generate four prosthesis for pelvic reconstruction. Titanium alloy (Ti6Al4V) is used to design the pelvic prosthesis. The optimal designs are compared with the natural pelvic bone by measuring the shape similarity index. Results show that the stress and displacement produced by the optimal designs are less than the natural pelvic bone. The induced peak stresses in the optimal designs are low, within linear elastic zone and below the yield strength of the alloy. The moderate to good shape similarity values indicate less complications such as dislocations, stability and constraining the range of hip joint.