1.1 This guide covers the clinical evaluation of the tissues surrounding metal-on-metal (MOM) hip replacement devices in patients using Magnetic Resonance Imaging (MRI). MOM devices must have articulating components manufactured from cobalt-28% chromium-6% molybdenum (Co28Cr6Mo) alloy (ASTM F 75,ASTM F 799, or ASTM F 1537). This guide does not address devices manufactured from any other alloys. This guide is applicable to both total and resurfacing MOM hip systems. Unless otherwise indicated, most MOM hip replacement devices have not been evaluated for safety and compatibility in the MR environment and have not been tested for heating or migration in the MR environment. 1.2 This guide describes the recommended protocol for MRI studies of patients implanted with MOM devices to determine if the periprosthetic tissues are likely to be associated with an adverse local tissue reaction (ALTR). Before scanning a patient with a specific implant, the MR practitioner shall confirm that the device is MR Conditional and that the scan protocol to be used satisfies the conditions for safe scanning for the specific implant. This guide assumes that the MRI protocol is intended to be applied to MOM devices while they are implanted inside the body. 1.3 The protocol contained in this guide applies to whole body magnetic resonance equipment, as defined in section 2.2.103 of the IEC Standard 60601-2-33, Ed. 2.0, with a whole body RF transmit coil as defined in section 2.2.100. The RF coil is assumed to have quadrature excitation. 1.4 The values stated throughout the standard shall be in SI units. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
On May 6, 2011, the FDA issued postmarket surveillance 522 orders to manufacturers of Metal-on-Metal (MoM) total hip replacements marketed in the United States. MRI is an important diagnostic tool to evaluate adverse local tissue reactions (ALTR) around hip replacements. This standard will provide guidance to clinical researchers regarding the optimization of scan sequences for clinical diagnostic evaluation of MoM hip arthroplasty Devices using MRI.
KeywordsMetal-on-metal, total hip replacement, magnetic resonance imaging, MRI, adverse local tissue reaction, ALTR
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development