An internal analysis conducted by Johnson & Johnson in 2011 after it recalled a troubled hip implant projected that the all-metal device could fail within five years in nearly 40 percent of patients who received it, newly disclosed court records show.
The analysis, which the company has never released, suggests that thousands of additional patients may have to undergo painful procedures over the next few years to replace the implant, known as the Articular Surface Replacement, or A.S.R. It also indicates that the episode’s cost to Johnson & Johnson will continue to grow.
The analysis was part of a small set of records unsealed Friday by a judge in Los Angeles Superior Court as part of pretrial proceedings in a lawsuit brought by a patient against the DePuy Orthopaedics unit of Johnson & Johnson.
Over 10,000 lawsuits have been filed against DePuy by patients who got an A.S.R. If the California case, which involves a man named Loren Kransky, goes forward this week as scheduled, it would be first of those cases to go to trial.
The records released Friday by Superior Court Judge J. Stephen Czuleger represent a tiny fraction of the tens of thousands of internal DePuy documents that the plaintiff’s lawyers say they have reviewed in connection with the California lawsuit. As a result, it is difficult to assess the strength of the case against the implant maker based on them.
Asked for comment, a spokeswoman for DePuy, Mindy Tinsley, said in a statement that the company’s internal analysis “was based on a small, limited set of data that could not be used to generalize” the overall replacement rate for the A.S.R. She added that any documents or partial testimony released before the trial “may not be able to be fully understood without proper context.”
For years, executives of DePuy insisted that the A.S.R. was performing on a par with other types of artificial hips, and said they moved to recall the device in mid-2010 when new data from an orthopedic registry in England showed it was failing more frequently.
But documents in the Los Angeles case and other lawsuits nationwide against DePuy are expected to reveal what actions company officials took – or did not take – before the A.S.R.’s recall and when they became aware of the implant’s problems.
Traditional hip implants, which are made out of plastic and metal, typically last 15 years or more before wearing out and requiring replacement. But the A.S.R., which had a cup and ball made of metal, began to fail in large numbers of patients soon after implant.
About 93,000 patients worldwide received an A.S.R., about one-third of them in the United States. Patients here received a version of the A.S.R. that was a traditional hip implant. Those outside the United States were outfitted with either the traditional version or a modified version used in an alternative joint replacement procedure known as resurfacing.
Both versions of the A.S.R., however, shared a central component, a metal hip cup that can shed tiny particles of metal debris as its moves. That debris has caused severe tissue and bone damage in hundreds of patients, crippling some of them.
One DePuy engineer acknowledged in court papers released Friday that company officials were aware in 2008 from reports by an English surgeon that the resurfacing version of the A.S.R. was releasing high levels of metallic ions, particularly in women.
In other pretrial testimony released Friday, Paul Voorhorst, DePuy’s director of biostatistics and data management, said that the company performed several reviews of A.S.R. failures in patients in the fall of 2011, a year after it recalled the model.
Based on the number of patients who had already undergone device replacement at the time, DePuy estimated that about 37 percent of patients who got an A.S.R. may need to get it replaced within five years of receiving it.
Last year, The New York Times reported that DePuy executives decided in 2009 to phase out the A.S.R. and sell off its inventories just weeks after the Food and Drug Administration asked the company in a letter for added safety data about the implant.
The F.D.A. also told the company at that time that it was rejecting its efforts to sell the resurfacing version of the device in country because of concerns about “high concentration of metal ions” in the blood of patients who received it.