FDA Investigates DePuy Hip Replacement Devices

Washington, DCFollowing the DePuy hip replacement recall, the US Food and Drug Administration (FDA) announced it is investigating concerns about metal-on-metal hip implants. The DePuy hip recall was announced after studies showed a higher than expected failure rate. Part of the problem with the DePuy hip replacement was that debris from the metal-on-metal DePuy hip was released into patients' bloodstreams, potentially causing metallosis and failure of the hip.

According to the FDA, the agency is "actively working in several areas to further assess the safety and effectiveness" of the metal-on-metal devices. Traditionally, hip replacement devices include a ceramic or polyethylene component. Some recent hip replacements, however, replaced the ceramic with metal, saying that the metal is more durable and ideal for younger patients who are more active. Furthermore, the metal-on-metal devices are believed to have a decreased chance of dislocation and a decreased chance of device fracture.

The problem with metal-on-metal devices is that debris can come loose and be absorbed into the patient's bloodstream, resulting in high metal-ion levels. Complicating matters is that reactions to the metal ions vary for each patient.

"Different people will react to these metal particles in different ways," the FDA notes. "At this time, it is not possible to know who will experience a reaction, what type of reaction they might have, when the reaction will occur or how severe the reaction will be. However, it is known that over time, the metal particles around some implants can cause damage to bone and/or tissue surrounding the implant and joint."

Patients who experience damage to the tissue and/or bone may suffer pain and may experience loosening of the device. In such situations, the patient may require revision surgery to remove and replace the device.

The FDA further notes that some patients who had high levels of metal ions in their bloodstream experienced symptoms or illness in other parts of their body, including their heart and nervous system.

Signs that a hip replacement device is failing include pain in the groin, hip or leg; swelling at or near the hip joint; and a change in walking ability. Other symptoms of problems related to metal ions in the blood stream include a change in general health, chest pain, shortness of breath, numbness, weakness and change in urination habits.

The FDA recommends that surgeons not use all-metal implants in patients who have metal sensitivity or a suppressed immune system. Meanwhile, the agency has requested that manufacturers send analyses of hip replacement parts that are retrieved from patients. The FDA also published a series of Web pages regarding metal-on-metal hip implants.