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

Iulian Antoniac,Sebastian Gradinaru,Dan Laptoiu,Cosmina Vigaru,Dan Ioan Stoia,Marius Vasilescu,Andreea Stoia

doi:10.37358/rc.20.4.8062

Abstract

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.

Highlights

Charcot osteo-neuroarthropathy (CN) is a severe foot and ankle pathology associated in diabetic patients
3.1 Simulation scenario I The equivalent elastic stress, equivalent strain and total deformation of the structure are presented for the simulation scenario I, for the Loading response (LR), Mid stance (MS) and Pre swing (PS) gait phases respectively (Figures 10, 11 and 12)
The arthrodesis stress are reduced, and the bolt screws exhibit low stress values. Taking into account their allowable stress of 260 MPa, it can be stated by comparison that at the LR phase of the gait implies no risk of failure of any of the 3 Midfoot Fusion Bolt (MFB) screws

Summary

Introduction

Charcot osteo-neuroarthropathy (CN) is a severe foot and ankle pathology associated in diabetic patients. Retrospective studies on patients with diabetic Charcot osteoarthropathy (CA) on the off-loading effect was conducted by Tomas M. Christensen et al They involve in the study 56 patients and consider an off-loading time of 141±21 days. An extensive study on patients with osteo-neuroarthropathy (CN) that exhibit severe instability and deformity of the foot was reported by Martinus Richter et al They use Midfoot Fusion Bolt (MFB) implants for realigning and fixation. The study recommends the use of minimum two bolts for avoiding the recurrent deformity of the foot [3]. Less postoperative fusion time is associated with these intramedullary nails

Objectives

Methods

Results

Conclusion