When Stephen Tower’s right hip gave out in 2006, he asked his surgeon to implant an artificial one — specifically, a metal-on-metal hip called the ASR XL, made by Johnson & Johnson. He knew what he was talking about: As an orthopedic surgeon, Dr. Tower specializes in complex hip replacements. But what he knew wasn’t enough to protect him from a defect in the device.

Five years after his surgery, and in excruciating pain, Dr. Tower underwent more surgery, this time to have the device replaced. When the surgeon sliced into his hip, what he saw looked like a crankcase full of dirty oil. Tissue surrounding the hip was black. Cobalt leaking from the ASR hip had caused a condition called metallosis, destroying not only local muscle, tendons and ligaments, but harming Dr. Tower’s heart and brain as well.

Despite Dr. Tower’s repeated efforts to warn his colleagues and the company that the implants were harming patients, Johnson & Johnson continued to market metal-on-metal hips. While it withdrew the ASR XL model from the market in 2010, citing slow sales, it continued to sell another, similarly problematic model, the Pinnacle, until 2013.

More than 9,000 patients filed suit against the company, and on Nov. 16, six New York patients won a $247 million trial verdict for serious harms caused by the Pinnacle hip implants and for failing to warn doctors and patients about its dangers. These suits and others are pulling back the curtain on what some doctors call the Wild West of medicine: the untested and largely unregulated medical device industry.