Updated 2 hours 16 minutes ago
A company's failure to manufacture a medical implant to the correct specifications may have caused the implant to shed harmful metal debris, injuring thousands of patients around the world, many of whom have had to undergo further painful surgery to remove the device.
The device in question, known as the DePuy ASR, was marketed in two versions: as a hip replacement prosthesis, and also as a hip resurfacing implant.
But only one – the total hip replacement version – was authorised by the Food and Drug Administration (FDA) to be used in the United States.
The device was designed, manufactured and marketed by DePuy International, a subsidiary of Johnson & Johnson, the world's largest medical devices company.
Nearly 100,000 patients around the world were implanted with the device - 5,500 of whom were in Australia.
DePuy announced a worldwide recall of the device in August 2010, after national joint replacement registries in Australia and the UK recorded rates of revision – or surgery in patients to remove the ASR device – which were far higher than average.
Tonight's Four Corners program, The Walking Wounded, tells the inside story of how the ASR was developed, tested, manufactured and marketed by DePuy, and how the widespread failure of the device was hidden from surgeons, some of whom were working with DePuy to monitor the progress of the device.
Mr Antoni Nargol, a consultant orthopaedic surgeon at the University Hospital of North Tees, in the north of England, is one of the surgeons who worked with DePuy when the ASR was put on the market.
His role was to audit the progress of the implant in his patients.
Later he worked with David Langton, an orthopaedic registrar who researches metal-on-metal hip prostheses, and who has published widely on the failure of the ASR hip – and why it failed.
Mr Langton and Mr Nargol have appeared as witnesses for patients seeking compensation for the failure of their ASR implants.
Mr Nargol told Four Corners: "When we measured the dimensions of the implants, they seemed to be outside of the specification, which was quite extraordinary because it's a precision implant."
He added: "A lot of the implants were not meeting the specification that they were meant to. So we put this to DePuy and we gave them some implants and said, 'Look, these are out of specification. Will you check them?' And they came back and said, 'We've looked at the implants and they're fine'. But what was interesting was that they weren't fine. They're absolutely not fine, but we were told they were."
Johnson & Johnson, in a lengthy statement to Four Corners, insists that the ASR device was manufactured to the correct specifications.
"DePuy has a robust quality control system for all of its products. We are not aware of any evidence that an ASR Hip System device did not meet manufacturing specifications. Further, it appears the sources of this claim are paid witnesses in litigation against the company," Johnson & Johnson said.
Company insider 'admitted implants were faulty'
But Mr Nargol told the ABC that his findings had been confirmed from high up within DePuy.
"I happened to be at a meeting and one of the senior people from the company came up to me and said to me, 'These implants that you'd brought over were not made correctly, were too small'. It was quite a shock because it was the opposite of what we'd been told by DePuy at the time."
The ASR device featured a very low clearance, or gap, between the head and the cup, which was intended to aid lubrication of the joint inside the body.
But Mr Langton, who carried out detailed measurements on devices which had been removed from patients after they had failed, told Four Corners: "There was an advertised dimension of the head and the cup, which the research and the advertisements were based on. But our findings are that that's not actually how they were manufactured, that the cup seems to be smaller than was actually intended."
Mr Langton told the ABC that between 20 and 40 per cent of the samples he had tested appeared to have been manufactured outside their advertised specifications. Mr Langton told Four Corners that the devices were measured on a coordinate measuring machine, the same machine which is used by DePuy in its factories.
The allegation that DePuy failed to manufacture the ASR device to its correct specifications follows on from other findings made by Mr Langton and other researchers, which suggest that the overall design of the ASR XL – the total hip replacement version of the device – led to more metal debris being shed in patients, than from comparable metal-on-metal devices.
Mr Nargol told Four Corners that in total, between 2004 and January 2009, he had implanted the DePuy ASR in about 500 patients.
He said 30 per cent of the ASR resurfacing devices had failed, as had 60 per cent of the ASR XL units.
Johnson & Johnson said in their statement to the ABC: "The totality of the data showed that up until mid-2010, the ASR Hip System was performing in line with other large diameter metal-on-metal monoblock and resurfacing hip devices. Ultimately, after receiving the new 2010 UK National Joint Registry data, the company decided that it was in the best interests of patients to voluntarily recall the ASR Hip System worldwide. This data showed a five-year revision rate of approximately 12 per cent for the ASR Hip Resurfacing System and approximately 13 per cent for the ASR XL Acetabular System, which was higher than expected and not in line with data previously reported in that registry."
Australian class action postponed
Tonight's Four Corners tells the story of a patient in the United States, Loren 'Bill' Kransky, who was awarded $US8 million in compensation by a jury for the injuries caused to him by his ASR hip replacement. The jury declined to award punitive damages against the company.
In Australia, a class action on behalf of hundreds of patients whose ASR devices have failed was due to come to trial in the Federal Court next week, and was set down for a 10-week hearing. But after volumes of fresh evidence were sent by DePuy to lawyers representing the patients, the trial has been postponed until next year.
In the United States, patients whose ASRs failed have been offered a base payment of $US250,000 in compensation, but Australian patients have been offered just $33,000 – although in many cases, the revisions and associated medical costs have been paid for by DePuy.
The Australian class action is being run by law firms Maurice Blackburn and Shine Lawyers. Maurice Blackburn's principal Ben Slade told Four Corners: "We want compensation for all those people who have been, we allege, injured by the defective product, and we think that that compensation should be paid at the level that Australian courts would consider to be the right amount of compensation, not the amount of compensation that the company chooses itself to pay."
He added: "We allege that in 2006 DePuy and Johnson & Johnson knew or ought to have known that the increased incidence of failure was greater than other metal-on-metal hip implants, and that in 2007 they knew that the increased revision rate was such that they should've taken action at that stage.
"It is incredibly sad that the victims are suffering so much. Certainly from the very outset we have demanded that the respondents come to the table and talk it through. Well, they haven't yet. Hopefully they soon will. At any stage now we hope there will be a mediation and there will be a settlement of these claims."
DePuy denies the design of the ASR was defective, and has not admitted liability for any harm or injuries caused to patients by the device.
DePuy told the ABC: "Regarding the class action proceeding in Australia, the company will defend itself against the allegations raised, and DePuy believes the evidence will show the company acted appropriately and responsibly."
Watch Four Corners at 8:30pm on ABC1.