Tens of thousands of metal on metal artificial hips are failing years earlier than expected and are requiring a second surgery to take the old device out and put in a new one. There has been no tracking system to follow how they do, although after the fact a tracking system is being implemented by orthopedists now. This is coming at a price of about $1 billion. These metal and metal hip replacements erode and leave high levels of cobalt and chromium in the surrounding tissues. This is not only toxic to the local tissues but is systemic as well. It can lead to severe pain in the affected joint and toxicity from cobalt that can result in neuropathies, hypercoagulation, hypothyroidism and cardiac problems.