What Does the U.S. Food and Drug Administration’s Letter to Hip Makers Mean?

The U.S. FDA ordered 21 manufacturers to collect information from patients.

The U.S. FDA ordered 21 manufacturers to collect information from patients in a recent letter to hip manufacturers. Click here for report. The three-page letter demands blood tests and other studies within thirty days. Here is a summary of the information and questions the FDA is requiring from manufacturers:

• The harmful events observed in patients with Metal-on-Metal (MoM) total hip replacement (THR) systems.
• The levels of serum and chromium in patients prior to THR.
• The patient population's average levels of chromium and serum in the blood for a minimum of eight years after the implant (patient population is the demographics and other particulars of a particular population).
• Do the average levels of chromium and serum in the blood increase during the first eight years (or the length of time on the market)?
• Reasons for revision (alteration of a medical device) and patient population's average levels of chromium and serum in the blood at the time of the revision.
• The number of patients with pain and biological and psychological symptoms associated with the THR.
• The quantity of harmful reaction of body tissues in patients who did not have a revision.
• How differences in revisions vary over time after the initial implant?
• What demographics have higher metal ion concentrations in their blood?
• What demographics have higher risks of needing revisions?
• What causes the THRs to fail?