The Analysis of Orthopedic Steel Implant – Chemical Compositions, Mechanical Properties, and Static and Dynamic Electromagnetic Signatures

Abstract

Abstract Steel implants remains a major class of orthopedic prosthesis. However, it is often difficulty to obtain the exact chemical compositions of the implants, as the process requires extensive analysis procedures in the laboratory. Nevertheless, this information is important, as it has been shown that variability of steel composition may be responsible for some of the early prosthetic failures. We previously developed a technique to identify metal alloys based on their magnetic signatures. We demonstrated that metals of different chemical composition would exhibit different electrical conductivity, and thus different magnetic field strengths when evoked by different levels of electric current. We further demonstrated that the electromagnetic signatures could be detected by the internal magnetometers located inside most smartphones as a part of the internal compass. In this manuscript we have compiled the electromagnetic signatures and magnetic force vectors of 516L steel alloy, a commonly used steel alloy for orthopedics implants. The manuscript further correlates the electromagnetic signatures to the chemical compositions and physical properties of the alloy. It is hoped that manufacturers can use the method to quickly verify the chemical compositions of the steel prior to prosthesis manufacturer, and also allow Pathologists to examined failed steel implants for chemical degradation that contributed to the implant failure.