Comments to the FDA on Premarket Approval for Metal on Metal Hip Replacements

Division of Dockets Management
Food and Drug Administration
5630 Fishers Lane, Room 1061 (HFA-305)
Rockville, Maryland 20852

Docket No. FDA-2011-N-0661
Effective Date of Requirement for Premarket Approval for Two Class III Preamendment Devices

The National Research Center for Women & Families strongly supports the FDA’s proposed order to require metal on metal (MoM) hips be approved through the premarket approval (PMA) process, which requires more rigorous testing of the devices than the 510(k) process.  MoM hips should have never been allowed on the market through the 510(k) process.

Risks to health from the MoM hips include loss of joint function, increased risk of premature device failure, and adverse tissue reaction and infection due to the release of metal ions.[1]  Reports by the United Kingdom’s Medicines and Healthcare Products Regulatory Agency, the Australian Orthopaedic Association, the American Academy of Orthopedic Surgeons, and articles in peer-reviewed journals such as the Lancet confirm the above problems.[2]

The Lancet article and an article in JAMA Intern Medicine noted that there is a significantly higher risk for revision in female patients.  In a commentary accompanying the JAMA Intern Medicine, we noted that “Sex-specific analyses are especially important in orthopedics because of substantial anatomical sex differences. These data…provide an important first step in understanding higher THA [total hip arthroplasty] revision rates in women.”[3]  Future PMA requirements for MoM hips should include sex-specific analyses.

Articles in the mainstream press have also documented problems with MoM hips, such as the 40 percent failure rate of Johnson & Johnson’s (DePuy Orthopaedics) MoM hips and that these defective devices have been used in tens of thousands of Americans.

From 2008 through 2012, MAUDE reported thousands of injuries for MoM hips product code JDL (Hip Joint Metal/Metal Semi-Constrained, With a Cemented Acetabular Component, Prosthesis) and product code KWA (Hip Joint Metal/Metal Semi-Constrained, \With an Uncemented Acetabular Component, Prosthesis). Additionally, thousands of MoM hips were recalled in recent years.

At a June 27, 2012 FDA Advisory Committee meeting, the National Research Center for Women & Families spoke about the problems caused by MoM hips including the lack of scientific evidence (clinical trials), the higher revision rates for women, the higher revisions rates compared to metal on polyurethane hips, and the lack of evidence that MoM hips have benefits that outweigh their risks.

We agree with the study reported in the Lancet that concluded that metal-on-metal hip replacements “give poor implant survival compared with other options and should not be implanted” and that all patients implanted with these devices should be carefully monitored, especially women.2

For the above reasons, we strongly support a PMA requirement for MoM hips. If companies want to sell MoM hips, they must be required to prove their safety first by going through the PMA process. We agree with FDA that “Recent reports and evaluations further support that reclassification [from class III to class II] of metal/metal hip systems is not appropriate.”1  MoM hips must require human clinical trials to prove that their benefits outweigh their risks before they are marketed to patients.

National Research Center for Women & Families


  1. Federal Register (January 18, 2013). Effective Date of Requirement for Premarket Approval for Two Class III Preamendments Devices [Docket No. FDA-2011-N-0661].
  2. A.J. Smith, et al. (March 13, 2012). Failure Rates of Stemmed Metal-on-Metal Hip Replacements: Analysis of Data From the National Joint Registry of England and Wales, Lancet, 2012:S0140-6736 (12) 60353-5.
  3. JAMA Intern Med. (Published online February 18, 2013). Commentary: Hip Implant Failure for Men, Women.