When participants left a two-day public hearing convened by the U.S. Food and Drug Administration (FDA) to discuss metal-on-metal hips (MoM) there were few answers and a lot of questions. The goal of the 18-member FDA advisory panel made up of surgeons, industry reps, and consumer advocates was to try and come up with some policy recommendations for use of the MoM hip implants that have left so many with life-altering complications.
The panel was also convened, not to consider a recall or reclassification, but to provide recommendations to doctors caring for MoM hip injured patients. MoM hips were originally marketed as an alternative to the traditional ceramic or plastic hips and were targeted for the younger, more active hip recipient. Many patients are in their 40s and 50s and face a lifetime of injury and complications.
There was no consensus on how to treat patients who suffer from toxic levels of chromium or cobalt, caused by metal debris which can get into the bloodstream in patients implanted with MoM hips.
The FDA was urged to avoid making any blanket recommendation that might interfere with the doctor-patient relationship, but really, why convene a panel unless some guidance is issued? There was agreement that the current data was not sufficient given that none came from prospective randomized trials.
The bottom line and the reason the panel was convened was that MoM hips have had a significantly higher failure rate than metal-on-ceramic or metal-on-polyethylene implants where the failure rates including deterioration and pain at 5-years are in excess of 10 percent.
There was also consensus that the larger the head size of the implant, the more failures, and that women seem to be experiencing a higher failure rate than men. There is also a difference in failure rate between the MoM total hip replacements and resurfacing, which had a higher success rate.
So what is a clinician to do? With almost 17,000 complication reports sent to the FDA, there were largely few answers. However, a skin patch test for metal sensitivity was recommended. Once a patient shows elevated levels of chromium and cobalt, no one can say what level is too high or what should be done. Chromium and cobalt ions can damage the lymph nodes, liver, kidneys and spleen. The metal ions are linked to cancers.
So the FDA convenes an expert panel with disappointing results, even as the DePuy Orthopaedics A.S.R. hips have been recalled from the market because of patient complications.