An internal study done by Johnson & Johnson estimates that the company’s all-metal implants have a 37 percent five-year failure rate, according to court documents recently made public. This means that all-metal hip implants are more than seven times more dangerous than traditional hip implants made of metal and plastic.

Thousands of Californians have received all-metal hip implants manufactured by Johnson & Johnson during the past few years. Doctors have mostly stopped using all-metal ASR hip implants because thousands of patients have experienced early device failures and other debilitating side effects.

Traditional hip implants last for about 15 years and have a 5 percent failure rate at five years. This means that metal-on-metal hip implants have a failure rate seven times higher than normal hip implants, making them one of the greatest medical device failures in recent history.

Testimony regarding the internal Johnson & Johnson study was recently made public as the first of thousands of ASR hip implant product liability lawsuits goes to trial. The study was made at a time when J&J was actively downplaying other studies that found similar high failure rates in all-metal hip implants.

Johnson & Johnson’s DePuy Orthopaedics division sold about 93,000 all-metal hip implants before recalling them in 2010. Internal documents show that the company decided to sell off its remaining inventory of ASR hip implants and phase them out after the Food and Drug Administration (FDA) raised concerns regarding their safety. There is substantial evidence that DePuy officials were aware that their hip implant devices were dangerous, but continued to sell them to maximize profits.

The FDA and several foreign agencies were flooded with reports of premature hip implant failure shortly after all-metal hip implants hit the market. The FDA was also alarmed about reports that the all-metal hip implants often shed dangerous metal particles that were destroying the bones and tissues of many patients.

More information about what exactly DePuy officials knew will come out as thousands of DePuy hip implant cases go to trial. The New York Times reports that some cases contain pretrial testimony from a DePuy engineer who said that company officials knew that the ASR implants were releasing dangerous metallic ions as early as 2008. The engineer said that the company decided to quickly redesign the dangerous implants instead of recalling them immediately.