Pharmaceutical

Hundreds of thousands may be at risk from faulty all-metal hip implants

Hundreds of thousands of people worldwide with all-metal artificial hips may be at risk for toxic ions seeping into their bloodstream and putting them at risk for serious health concerns, according to an investigation by the British Medical Journal (BMJ) and the British Broadcasting Corp (BBC). The agencies compared the metal hip crisis to another medical device health crisis, toxic-leaking breast implants, which an estimated 400,000 women in 65 countries (excluding the United States) received.

The European Union (EU) is currently embroiled in a scandal involving  a type of breast implant made by French company Poly Implant Prothese (PIP). It appears the device was made with non-medical-grade silicone and implanted in women. The implants are prone to leaking the gel, which if released can cause inflammation in the surrounding tissue and may put women at risk for developing cancer. The issue has brought to light how medical devices are approved for use in patients both in Europe and the United States.

As the EU began investigating how these defective breast implants were approved for use in the first place, the U.S. Food and Drug Administration (FDA) was conducting an investigation of its own into a new type of hip implant made with all metal parts. The devices were designed to be more durable than traditional hip implants using plastic or ceramic parts, but they were surprisingly failing at a higher than expected rate. Not only that, it seemed they were leeching chromium and cobalt into the bloodstream, potentially causing a type of blood poisoning. As in the situation with the PIP breast implant gel seeping into the bloodstream, doctors raised concerns about cancer.

The FDA’s investigation was prompted by a recall of two metal-on-metal hip implants made by Johnson & Johnson subsidiary DePuy Orthopaedics, the ASR XL Acetabulator hip replacement and hip resurfacing systems. Complaints made to the FDA showed that the problems weren’t limited to DePuy’s ASR implants, but were being reported in connection to a variety of all-metal implants made by other manufacturers. This led the FDA to conduct an investigation into the implants, calling on manufacturers of these devices to collect data on problems. It has also shed light onto the lax practices of approving medical devices both in the United States and Europe.

The EU’s process for approving medical devices is typically less in-depth than in the United States. Both countries require studies to show that the devices are effective; only the U.S. requires proof that the devices are safe. However, the FDA allows medical devices that are similar to ones already on the market to be approved without clinical testing. This is how many of the the metal hip implants, such as DePuy’s ASR, were approved for use in the U.S.

The FDA and Congress are currently considering proposals on how to better ensure medical devices are safe before allowing them to be used in the United States.

Sources:
Businessweek
The Atlantic