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?