MRI Interactions with the Zimmer Natural Nail™ Implant System

Magnetic Resonance Imaging (MRI) is a common diagnostic medical procedure. Although it is often safe to perform MRI on an individual that has an orthopaedic device, potential safety issues do exist. Implants fabricated from ferromagnetic materials may experience displacement and torque in the large magnetic field present in MRI units. Under certain circumstances, alternating electrical currents may cause heating of the implant and surrounding tissue irrespective of the magnetic characteristics of the implant. Also, the possibility of substantial image artifacts may compromise image quality. In 2008, the Food and Drug Administration (FDA) released a guidance document entitled, “Establishing Safety and Compatibility of Passive Implants in the Magnetic Resonance Environment”. This document requires orthopaedic device manufacturers to establish the safety of their devices from a magnetic force, magnetic torque, radio frequency induced heating, and image artifacts perspective. This study will discuss the results of MRI compatibility testing performed on the Zimmer Natural Nail tibial nail system in a 1.5 and 3.0 Tesla MR environment.