A federal judge has expanded the number of product liability cases that should prepare for “bellwether trials” in litigation concerning the recalled hip implants Stryker Rejuvenate and ABG II.

Bellwether trials are intended to see how juries may rule on similar evidence and testimony. Bellwether cases help reduce duplicative discovery, avoid conflicting rulings from different federal judges and mitigate the inconvenience of the various parties, witnesses and the courts.

In a Sept. 19 order, U.S. District Court Judge Donovan Frank in Minnesota – where about 2,000 of the 4,000 defective Stryker hip implant lawsuits have been consolidated as part of a multidistrict litigation– ruled that more than 750 cases may begin preparing for trials, which are set to start next summer. The original pool of potential bellwether cases was 500. Both parties will be allowed to pick any Stryker hip lawsuit filed through July 1, 2014 to be considered for bellwether trial, Frank ruled.

Hip Replacement Complications Lead to Thousands of Lawsuits

In November, Johnson & Johnson agreed to pay $2.5 billion to settle some 8,000 DePuy hip lawsuits filed by patients who had risky hip revision surgery to replace the company’s metal-on-metal hip implants, which failed at higher rates than traditional hip implants.

Nearly 93,000 people worldwide – about 12,000 in the United States – received the DePuy ASR XL Acetabular hip implant or the DePuy ASR hip resurfacing system implant, which were recalled by DePuy Orthopaedics, a Johnson & Johnson subsidiary, in 2010. More patients are expected to undergo hip revision surgery for the implants in the future. Many of these patients are eligible to claim compensation for these faulty hip implants.

In the Stryker Rejuvenate lawsuits, the plaintiffs allege that the product was “defectively designed and unreasonably dangerous,” resulting in the hip implants becoming corroded, leading to the device’s failure. The Stryker Rejuvenate – whose defective design caused tiny pieces of metal debris to be released from the chromium-cobalt neck rubbing against the titanium femoral stem — was recalled in July 2012.

Thousands of patients who had hips replaced with metal-on-metal devices have experienced high ion concentrations of cobalt and chromium and tissue reactions. The devices fail at higher rates than traditional implants with plastic bearings according to recent studies.

A medical expert specializing in adult reconstruction and joint replacement told Modern Medicine that problems caused by implants typically fall into three categories: those needing revision surgery (which costs about $100,000), not symptomatic or suffering any pain, but MRIs indicate that they have adverse tissue reactions and elevated metal ion levels (they may also require revision surgery), and those with elevated ion levels who need to be monitored.