A massive settlement has been announced over the DePuy hip implant lawsuits. The settlement agreement is set to resolve roughly 12,000 lawsuits, bound together in multidistrict litigation (MDL) or mass tort, over the allegedly-defective metal-on-metal hip implant.

DePuy is a subsidiary of Johnson & Johnson. The company produced a metal-on-metal hip implant called the ASR hip implant, which has been at the crux of these hip implant lawsuits.

Hip implants are artificial joints, designed to replace the interface between the top leg bone (femur) and the hip bone (pelvis). This joint can wear out with age due to a condition called osteoarthritis. However, most artificial hip joints have a ceramic or polymer interfacing surface.

Several companies, including Johnson & Johnson’s DePuy, began manufacturing hip joints with metal-on-metal surfaces. Unfortunately, these joints have been alleged to have serious complications not seen in other types of artificial hip joints.

Research studies have suggested that metal-on-metal hip implants have an increased risk of failure and other complications compared to other types of artificial hip joints.

In fact, the data that led to the August 2010 DePuy hip implant recall actually indicated that as many as 12.5 percent or one-eighth of DePuy implants would prematurely fail. However, new data suggests this number may be even higher — as high as 45 percent.

Additionally, it has been alleged that metal-on-metal implants can grind against themselves, “shaving off” microscopic metal flakes, that more easily dissolve into toxic metal ions. Allegedly, these ions can cause inflammation and promote the formation of tumor-like growths around the joint.

The joint status report, issued on June 27, stated that attorneys for DePuy and various plaintiffs had reached a settlement agreement. The report stated that $2.4 billion had been set aside for settlements, but that the payouts could ultimately reach $4 billion as various medical expenses are totaled.

The report also stated that 98.3 percent of eligible individuals had already enrolled in the payout program. The settlement is designed to resolve the majority of the hip implant lawsuits, which have been bound together in multidistrict litigation.

Multidistrict litigations or MDLs are a sort of coordinating a group of similar lawsuits that function as a unit, which are common in drug lawsuits, since injuries tend to vary, and they can be streamlined by combining them into a single MDL.

Several states have also filed metal-on-metal hip implant lawsuits against DePuy, alleging that the company has defrauded their various state-level Medicare programs by selling the allegedly-defective implant.

The DePuy Hip Implant MDL is In re: DePuy Orthopaedics Inc., Pinnacle Hip Implant Products Liability Litigation, MDL No. 2244, in the U.S. District Court for the Northern District of Texas.