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Johnson & Johnson never released those projections for the device, the Articular Surface Replacement, or A.S.R., which the company recalled in mid-2010. But even as the medical products giant was performing that analysis, it was publicly disputing similar findings from a British implant registry about the device's early failure rate.

The company's analysis also suggests that the implant is likely to fail prematurely over the next few years in thousands more patients in addition to those who have already undergone painful and costly procedures to replace it.

The internal Johnson & Johnson analysis is among hundreds of internal company documents that are expected to become public as the first of over 10,000 lawsuits by patients who got an A.S.R. prepares to go to trial this week. The A.S.R. episode represents one of the biggest medical device failures in recent decades and the forthcoming trial is expected to shed light on what officials of Johnson & Johnson's DePuy Orthopaedics division knew about the device's problem before its recall and the actions they took or did not take.

The trial, which is expected to begin Friday in Los Angeles Superior Court, may also provide a guide to both the financial and reputational consequences of the A.S.R. episode to Johnson & Johnson. Last year, the company took a $3 billion special charge, much of it related to medical and legal costs associated with the A.S.R. DePuy has offered to pay patient costs for replacement procedures.

The A.S.R. belonged to a once-popular class of hip implants in which a device's cup and ball component were both made of metal. While the A.S.R. was the most failure-prone of those implants, surgeons have largely abandoned using such devices in traditional hip replacement because their components can grind together, releasing metallic debris that damages a patient's tissue and bone.

On Friday, Judge J. Stephen Czuleger, who is presiding over the Los Angeles case, unsealed a number of motions that contained portions of a pretrial deposition of a DePuy official as well as related company records. Those disclosures, such as the company's estimate of the A.S.R.'s failure rate, represent only a tiny fraction of the information that will become public if the trial proceeds. Over the past two years, plaintiffs' lawyers working on A.S.R.-related lawsuits have reviewed tens of thousands of internal DePuy documents and deposed dozens of company executives.

Executives of DePuy have long insisted that their handling of the A.S.R. was forthright and appropriate. In mid-2010, when DePuy recalled the implant, officials said they were doing so because data that year from the National Joint Registry of England and Wales showed for the first time that it was failing prematurely at a higher rate than competing implants. In 2011, the British implant registry updated its projected failure rates for A.S.R. patients who had had it the longest, saying it was failing in one-third of them. It was that estimate that was challenged by DePuy.

About 7,000 of the A.S.R. lawsuits have been consolidated in a federal court in Ohio. An additional 2,000 cases have been consolidated in a California state court. The California case chosen to go to trial this week was selected because the plaintiff, a man named Loren Kransky, is suffering from cancer and may not live much longer, lawyers involved in the case said. DePuy has already settled a few A.S.R. cases before trial and it may choose to do so in Mr. Kransky's case as well.

About 93,000 patients worldwide received an A.S.R., about one-third of them in the United States. There are two versions of the A.S.R., one used in traditional hip implants and the other used in an alternative replacement procedure known as resurfacing. Only the traditional implant was sold in the United States.

Both versions of the A.S.R., however, used the same metal hip cup as part of their design.

Asked for comment about the company's internal analysis, a spokeswoman for DePuy, Mindy Tinsley, said in a statement that it "was based on a small, limited set of data that could not be used to generalize" the overall failure rate for the A.S.R.

In 2011, when DePuy challenged the British joint registry's findings, the company made similar comments. But other medical organizations have also projected very high failure rates for the A.S.R.

Hip implants, which are traditionally made from metal and plastic, often last for 15 years before they wear out and need to be replaced. Such devices can fail prematurely for a variety of reasons but the early replacement rate is typically 1 percent annually, or 5 percent at five years.

In pretrial testimony, 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. might need to have 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 additional 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 the United States because of concerns about "high concentration of metal ions" in the blood of patients who received it.

In other pretrial testimony released Friday, a DePuy engineer stated that company officials were aware in 2008 of reports by an English surgeon that the resurfacing version of the A.S.R. was releasing high levels of metallic ions, particularly in women. As a report, company officials felt they had to move quickly to redesign the implant.