A United States court is considering whether patients should be compensated for the faulty implants.
As part of the case it has been revealed that Depuy knew about problems much earlier than when they recalled the implants.
Depuy was reportedly told as early as 2006 of difficulties with the implants, with leading British orthopaedic surgeon David Beverland warning in emails that patients were suffering, the Daily Telegraph newspaper reported yesterday.
It was not clear what specifically he was warning Depuy about.
The Wall Street Journal reported that Depuy company figures showed problems with the "survival rate" of the implants in 2007.
The implants were supposed to last a lifetime.
In March 2008, the company's marketing team discussed ways of using different data to market the implant which meant it could claim a 99 per cent success rate.
The implants were finally recalled in 2010. A company analysis found that nearly 36 per cent of them were expected to fail within five years.
Last year up to 50 New Zealand patients who received the implants instructed a London barrister to seek compensation in Britain where the implant was made. ACC legislation prevents them from suing for pain and suffering here.
New Zealand man James Elliott is part of the group claiming compensation in Britain.
He said yesterday that the lawyers had so far won the right to claim, but Johnson & Johnson now had the right to argue in court that the claims should be brought in New Zealand.
Mr Elliott said there was a "narrative" US lawyers had been building for a while and "that is exactly this, that the company knew for a long time about the dangers", he said.
"It's not the first time I've heard of so-called smoking gun documents coming out of the discovery process that they're now well underway with in America."
It fitted into the scheme of Johnson & Johnson and particularly the way it had handled the case, he said.
US Drug Watchdog said it had been dealing with the metal on metal "mess" for two years and had known about the cobalt and chromium poisoning for at least 18 months.
But the US Food and Drug Administration had only just said it was concerned about tissue damage related to elevated levels of cobalt and chromium, which prompted the patient advocate's advice to recipients.
About 140,000 Americans and 10,000 Britons have been fitted with the implant.
March 2008
A marketing team with the company which made metal hip units discussed ways of using different data to market the implant which meant it could claim a 99 per cent success rate
2010
Devices recalled after data revealed a high replacement rate due to failure
