Two cases filed against Wright Medical Technology Inc. and MiroPort Orthopaedics Inc. have been consolidated by a California federal judge. The lawsuit accuses the companies of hiding a crucial defect in their metal cup-and-ball hip implants.
The two plaintiffs allege the Profemur Total Hip System broke “suddenly and catastrophically,” leading to emergency surgery that requires damaging the femur. In one case the Profemur implant lasted only 37 months, the other a mere 20 months.
The lawsuit comes in the midst of Wright Medical’s multidistrict litigation (MDL) battle against claims that its Conserve Hip Implant, a metal-on-metal hip implant system, has been releasing metal ions into the bloodstream by the parts rubbing together during normal use.
The earlier models of the Profemur hip used titanium, which led to many broken stems as well. Instead of changing the whole design, Wright simply changed the metal used.
Metal-on-metal hips are usually made of a stainless steel alloy containing cobalt and chromium, and were intended to be a design that would reduce wear between the ball and cup. Instead, the opposite occurred. The design has been known to fail in as little as five years, with hip implants made from other materials lasting 20 years or more.
Many patients with metal-on-metal implants have experienced higher levels of cobalt and chromium in the bloodstream as a result of the metal wear. Elevated cobalt levels have been linked to tremor, poor coordination, cognitive decline and depression as well as reportedly damaging effects on the heart, hearing and vision. This type of metal poisoning has also been linked to high blood pressure, as well as dizziness and skin rashes.
Metal-on-metal hip implant manufacturers such as Wright Medical, DePuy Orthopaedics and its parent company Johnson & Johnson, Stryker, Smith & Nephew and Zimmer Biomet Holdings have been facing thousands of lawsuits in recent years over their hip implant designs.