Using Stainless Steel and Titanium Alloy in Charcot Foot Reconstruction. FEA Simulation and Clinical Case

The aim of the study was to simulate a clinical case of Charcot foot reconstruction, using finite element analysis (FEA). Our work starts from a clinical failure case of Charcot arthrodesis, were one stainless steel Midfoot Fusion Bolt (MBF) prematurely failed. Starting from CT images a 3D model of the foot was reconstructed and together with the intramedullary bolts a virtual assembly was build. In addition, a second 3D model containing 3 MBF screws and one titanium locking compression plate (LCP) was constructed. The loading conditions used in FEA were extracted based on foot biomechanics according to the gait phases. The results are showing the critical sections of the bolts and also the stress shielding effect that appears on the bolts when the plate is used as supplementary fixation element. By comparing the stress values on bolts and plate with the yield strength of stainless steel and titanium alloy that are regularly used for manufacturing these implants, a valid reconstruction solution was found. This result can help surgeons in establishing the proper bolt insertion and plate positioning for minimizing the implant failure risk.