A new Stryker hip lawsuit has joined the mass litigation against the company, alleging that their metal-on-metal hip implants are defective and dangerous.

In this case, plaintiff Pamela B. of Connecticut had her right hip joint replaced with a Stryker hip implant. The Stryker hip implant was a metal-on-metal hip implant, a type of hip implant that has become embroiled in lawsuits due to allegations that they are defective and more prone to complications than other types of hip implants.

Metal-on-metal hip implants are a type of hip implant in which both of the moving surfaces of the joint are made of metal. In most other hip implants, the moving surfaces are coated in polymers, ceramic, or in the oldest hip implants, ivory.

In the 2000s, a number of companies, including Stryker, began to market metal-on-metal hip implants. Since these new metal hip implants, like the Stryker hip implant, were similar to existing models of hip implants, they were able to take advantage of a controversial U.S. Food and Drug Administration (FDA) regulation, 501(k), which allows medical companies to skip many stages of FDA testing, on the grounds that their device is “substantially similar” to existing technology.

However, reports of hip implant complications flooded in, and allegations that Stryker hip implants and other metal hip joints were more dangerous than other hip implants led to numerous lawsuits and hip implant recalls.

Many of the allegations against the Stryker hip implant and other metal hip joints is that metal hip implants are more prone to serious complications. Allegedly, the moving surfaces of metal hip implants may grind against each other, “shaving off” microscopic bits of metal.

While these metals, including cobalt and chromium, are safe for use in the human body as solid pieces, this microscopic dust of metal may more easily dissolve in blood and other internal bodily fluids, allegedly forming toxic metal ions. This can allegedly cause serious reactions, including inflammation around the joint and painful growths called pseudotumors. Additionally, it has been alleged that metal hip implants like the Stryker hip are more prone to corrosion and fretting, causing the joint to fail.

In this case, Pamela had the Stryker hip implant grafted into her body by surgeons in April 2013, replacing her right hip. However, at a follow-up appointment, physicians found elevated levels of cobalt in her blood in April 2014, and revision surgery to remove the Stryker hip implant was scheduled. In July, the Stryker hip implant was removed from her body and replaced with a different hip implant. A follow-up in October found much lower levels of cobalt in her blood.

Revision surgery to remove a Stryker hip implant, or any metal-on-metal hip implant, is a trying ordeal. In addition to the same risks and discomforts of a regular hip replacement surgery, revision surgery consists of removing the Stryker hip implant.

Additionally, since the process of implanting a Stryker hip implant requires surgeons to cut away bone from the hip joint and replace it with the implant, surgeons have less bone to work with during a revision surgery, making it more technically challenging.

The Stryker Hip Lawsuit is Case No. 0134, in the U.S. District Court for the District of Connecticut.