As hip replacement lawsuits continue to make the news, many patients ask “are metal on metal hip implants still used?” Happily, this form of hip replacement device isn’t still on the market, but many patients claim that they still are suffering from an injury caused by them.

The Arthritis Foundation notes that metal on metal hip implants originally were advertised as a more durable alternative to metal-on-ceramic or metal-on-polyethylene. Instead, they created unexpected problems for patients.

In a metal on metal hip replacement device, an artificial metal hip ball fits into an artificial metal socket. So, metal rubs directly on metal, whereas in the cases of other hip implants, metal rubs on another substance — ceramic or polyethylene (plastic).

The Arthritis Foundation goes on to note that metal on metal hip implants have a higher failure rate than other hip implants for a number of reasons. According to a 2012 study, 6.2 percent of metal-on-metal hip implants failed after five years, compared to just 3.2 percent of ceramic hips and 1.7 percent on metal on polyethylene hips. 

According to research, this rubbing can cause small metal fragments to fret off from the metal implant, causing irritation, infection in surrounding tissues, and a rise in metal levels in a patient’s blood. Additionally, bone can erode because of the metal fragments, leading to failure.

Additionally, the metal fragments that can fret off of the hip implant can prevent bone growth, which researchers suspect may result in failure of the implant. Reportedly, bone cells (osteoblasts) develop from mesenchymal (MSC) stem cells, which can develop into a number of different types of cells including bone cells.

Allegedly, the metal fragments can inhibit the MSC function, which can prevent them from being able to form more bone and may prevent a hip implant from being a success. Allegedly, the MSC cells are less able to turn into bone cells when they have been exposed to metal fragments.

So, when a hip implant fails, a patient may have to have revision surgery to remove the metal-on-metal hip replacement and replace it with a different device. Revision surgeries are risky, and in fact pose a higher risk of complications and infections than an initial hip replacement surgery. So, patients who had a metal-on-metal hip implanted may suffer injury not just from the device itself but from the revision surgery.

An article published in the journal Biomaterials reports that metal on metal implants can result in “vast amounts” of metallic particles. The study author, Carsten Parka, MD, medical director of the Center for Musculoskeletal Surgery at Charité – Universitätsmedizin in Berlin, asserts that in future, an understanding of how the materials used in an implant affect the body is essential in creating a safe and long-lasting implant.

Though the easy answer to the question to “Are metal on metal hip implant still used?” is “not for total hip replacements,” metal-on-metal devices are still used in hip resurfacing surgeries. The surgeries don’t replace a hip entirely but cover an existing hip ball with a metal cap which is fitted into a metal socket. Though there has been more success reported with the metal-on-metal resurfacing than with a metal-on-metal device in a hip replacement, there may be similar risks to some degree. 
If you had a metal on metal hip implant and it caused you injury, and you had to have revision surgery because of your injuries and implant failure, you may have a legal claim. Patients with a legal claim may be entitled to compensation for the physical, emotional, and financial injuries associated with hip replacement failure due to a design defect in the implant.