FDA: Metal-on-Metal Hips Must Have PMA

Marie Thibault

Following years of deliberation, FDA this week is requiring a PMA for metal-on-metal total hip replacements. The final order, set to be published in the Federal Register on February 18, applies to metal-on-metal semi-constrained hip joint implants with either a cemented or uncemented acetabular component.

Sponsors with metal-on-metal hips already on the market have 90 days from publication to file a PMA with FDA. If a metal-on-metal hip implant is on the market but does not have a PMA filed or an approved IDE for investigational use, FDA will consider it adulterated and "intends to take appropriate action to ensure compliance," according to the final order.  

This week's final order follows a proposed order published in January 2013. Years before that, FDA held a device classification panel in 2001 that determined metal-on-metal hip implants should be continue to be considered Class III devices. In the final order, FDA wrote that "the problems identified in the medical device reporting systems and recalls for MoM hips further indicate the need to review these devices under a PMA to provide reasonable assurance of their safety and effectiveness."

In the intervening years, as concerns about the risks of metal-on-metal hip implants have grown, FDA has been involved in numerous efforts to learn more about the issue, including requiring postmarket surveillance studies, publishing a safety communication, reviewing medical literature and adverse event reports, and starting the International Consortium of Orthopaedic Registries. At the time that postmarket surveillance studies were ordered in 2011, there were five manufacturers with commercial metal-on-metal hips in the United States. Since then, some manufacturers, including Smith & Nephew and Johnson & Johnson's DePuy, have pulled their offerings from the market.

The 2013 proposed order was open to public comment. FDA noted that among the comments was a suggestion that standards for metal ion levels in patient serum be adopted. FDA wrote in the final order that the lack of access to such testing, inconsistency in results, and need to show correlation between metal ion levels and clinical outcomes make it difficult to create such a standard now. However, the agency wrote that it will use data from postmarket surveillance studies to determine if any advice can be given.

Another commenter asked FDA to set revision surgery standards, which FDA shied away from by pointing out that "revision surgery involves a complex clinical decisions that falls within the practice of medicine, which FDA generally does not regulate."

Marie Thibault is the associate editor at MD+DI. Reach her at [email protected] and on Twitter @medtechmarie. 

[Image courtesy of STOCKDEVIL/FREEDIGITALPHOTOS.NET]