On January 18, 2013, FDA issued a proposed order that would require the filing of a premarket approval application (PMA) or a notice of completion of a product development protocol (PDP) for metal-on-metal hip joint implants.

Metal-on-metal hip replacement implants were marketed prior to the Medical Device Amendments of 1976, which gave FDA authority over medical devices.  Thus, although metal-on-metal hip implants are class III “high-risk” devices, which usually require approval of PMAs, metal-on-metal hip implants have been regulated under the 510(k) premarket notification program as preamendment devices.

The 1976 amendments established three classes of devices reflecting the risks of the devices and the regulatory controls necessary to ensure their safety and effectiveness: class I (general controls), class II (special controls) and class III (premarket approval).  Preamendment class III devices and devices found substantially equivalent to preamendment devices though the 510(k) premarket notification pathway could be marketed without PMAs until issuance of a final regulation requiring premarket approval.  The Food and Drug Administration Safety and Innovation Act (FDASIA), enacted in July 2012, amended this obligation by requiring an administrative order rather than rulemaking.   For all preamendment class III devices, FDA is required to either issue orders requiring PMA approval or reclassify them into class I or class II.  However, 19 different types of preamendment class III devices, including metal-on-metal hip implants, had not yet been addressed by the agency.

The proposed order includes FDA’s proposed findings regarding the degree of risk of injury designed to be eliminated by requiring PMA approval and the benefits to the public from the use of the device.  FDA stated that the distinctive risks associated with metal-on-metal hip implants, as compared to other types of bearing surfaces, are the wear particles generated and release of metal ions, which may cause adverse tissue reactions and may lead to an increased risk of premature device failure.

FDA also cited the recent recalls of metal-on-metal hip implants and several academic articles, such as the Australian Orthopaedic Association National Joint Replacement Registry 2010 Annual Report and the Academy of Orthopedic Surgeons’ technology overview, which reported higher revision rates with metal-on-metal implants than with other hip implants.  To FDA, these indicated that “preclinical testing currently used to support marketing clearance of these devices has not been sufficient to mitigate the risks associated with these devices and identify potential clinically-relevant failure modes.”

FDA’s proposed order followed other recent developments regarding these products.  On January 17, FDA issued a Safety Communication regarding metal-on-metal hip implants.  This communication was directed to orthopedic surgeons, health care providers, and patients who are considering or have received metal-on-metal hip implants.  FDA set forth recommendations for pre-surgery consideration and post-surgery patient follow-up.  These included recommendations relating to diagnostic imaging, assessment of metal ion levels, and device revision.   Also, shortly before FDA’s announcement, on January 10, a group of researches published an article in the New England Journal of Medicine citing “serious flaws” in the 510(k) procedure for metal-on-metal hips.  The authors requested that the FDA close the alleged “loophole” that allows potentially high risk devices to reach the market without undergoing clinical trials.

Once FDA issues a final order, manufacturers wishing to continue to market metal-on-metal hip implants will need to file a PMA or notice of completion of a PDP within 90 days of publication of the final order.  Manufacturers will be permitted to continue marketing the devices during FDA’s review, if the PMA or notice of completion of the PDP is timely filed.  FDA intends to review any PMA within 180 days and any notice of completion of a PDP within 90 days.  If a PMA or notice of completion of a PDP is not filed within 90 days, the device will be deemed adulterated.

Interested persons may submit comments on the proposed order electronically at regulations.gov.  Comments are due by April 18, 2013.