The first of more than 6,000 DePuy Pinnacle hip replacement lawsuits is getting its day in court this week.

At issue is the design of the Pinnacle hip implant. When the parts move against one another, they shed microscopic metal fragments into the patient’s body, leading to metallosis and early failure of the hip replacement. Enough similar claims for metal blood poisoning have been filed that a multidistrict litigation (MDL) was created. The litigation was centralized for pretrial proceedings in the U.S. District Court for the Northern District of Texas. Now bellwether cases are being heard.

Bellwether trials are early trials that look at a small group of cases to gauge how juries may respond to testimony and evidence. The first hip implant lawsuit being used to gauge jury response in the DePuy Pinnacle MDL is a complaint filed by 58-year-old plaintiff Kathleen Herlihy-Paoli of Montana. A recipient of a DePuy Pinnacle metal hip in 2009, Herlihy-Paoli later reported pain. According to court records, she was found to have cobalt blood serum levels 85 times that of a normal person. She had to have the DePuy hip implant removed in 2011, and deal with the physical and fiscal ramifications thereafter.

Herlihy-Paoli’s lawyers told the jury that “Johnson & Johnson and the DePuy Orthopaedics subsidiary aggressively overmarketed the hip replacements, lied about complication rates associated with metal-on-metal hips and failed to warn people that they were being used as ‘guinea pigs.'”

Once this case is resolved, additional bellwether trials are scheduled to be heard on November 3 and January 12. If the DePuy Pinnacle trials do not look positive for J&J, they could decide to settle the hip implant lawsuits, avoiding the need for thousands of other cases to be set for individual trials.

Metal-on-metal (MOM) hip implants can cause a variety of complications, including metal blood poisoning (metallosis). On average, the U.S. Food and Drug Administration (FDA) receives over 1,000 adverse reports annually for hip implant issues, and numerous lawsuits have been filed against Biomet, DePuy and other hip implant manufacturers for allegedly faulty hip replacements.

Pinnacle, Not the Only Hip Implant

The ASR hip implant is another hip replacement offering from J&J and DePuy. Approved as a “substantial equivalent” to the Pinnacle MOM hip, it underwent a recall for failures in August 2010. Over 12,000 ASR lawsuits were filed nationwide. A number of hip implant lawsuits went to trial and received conflicting decisions. Rather than risk thousands of possible negative decisions, DePuy and Johnson & Johnson agreed to settlements of close to $2.4 billion.

The manufacturers claim the Pinnacle implant is safe, but early evidence in the current trial suggests that DePuy ignored testing recommendations to see if metal-on-metal had shedding issues. This alleges that DePuy knew, or should have known, about the metal poisoning risks since 2001. FDA warnings for metal-on-metal hip replacements and guidelines for future testing weren’t released until 2013.

Lack of research, poor design, and lack of warnings about the potential risks is at the heart of metal-on-metal hip implant lawsuits nationwide. DePuy is not alone; other hip manufacturers face similar accusations. Other metal hip MDLs include Biomet for its M2A Magnum and the Wright Medical Conserve Cup.