With the major failings of several joint implants already a matter of international record and the details of another starting to emerge, a more comprehensive system of surveillance is long overdue, says one expert.
David Langton, a surgical researcher at the University Hospital of North Tees, launched spinoff business ExplantLab, so disconcerted was he by his findings.
His aim, to help pave the way to a cost-effective means of analysing the problems caused.
Well-known prosthesis failures include the 3M Capital hip of the 1990s and then, in the noughties, the ASR (articular surface replacement) ‘metal on metal’ hip made by DePuy, a subsidiary of American healthcare giant Johnson & Johnson.
While the 3M scandal triggered the creation of the UK’s National Joint Registry, the accompanying system has two potential weaknesses, said David Langton.
“Manufacturers themselves are consulted prior to the release of the registry and it is possible this may impact on the wording of a report,” he said.
“In Australia, there is a Chinese wall between manufacturers and medics.”
The second weakness is the fact that failing implants are not sent off for analysis after they have been removed.
“Here is the critical thing,” he said, “it is standard clinical practise throughout the world, including in the UK, for a surgeon to remove a device and, even when it has happened much earlier than expected, it is just thrown in the bin.
“Patients usually give consent to upload their details to the national database, so there should be millions of records now providing a clear picture of what’s going on.
“But one, there is a time-lag of year between something going wrong and the indication of that appearing on the National Joint Registry, and two, there is little or no investigation of the root cause of the problem.”
Far from being critical of those behind the implant failures, he is instead calling for the introduction of a more robust system of surveillance.
That would begin with requiring surgeons to send failed devices for analysis.
If regulation required an answer, the use of a potentially problematic prosthesis could be nipped in the bud sooner rather than later – before thousands of patients’ lives were blighted by it.
Acting on reports the metal on metal wear was producing metal debris that could destroy soft tissue around the joint and, in some cases, release ions of cobalt and chromium into the blood and cerebral spinal fluid, DePuy withdrew the ASR hip joint in 2010.
But by then, it had already been implanted in more than 93,000 people worldwide.
He said: “We experienced this again with the Pinnacle metal on metal device. We knew the products were not performing as well as expected and when the explanted components were analysed, we found that they were not manufactured correctly.
“A significant percentage should not have left the factory. We found that out 10 years ago, it made the front page of a national newspaper, yet the NHS has not acted on it.
“Patients actually lost their product liability cases in court as no one backed our findings up.
“Literally this year, a DePuy funded retrieval centre finally published evidence to substantiate ours, but it’s several years too late.
“It seems to have dodged the issue until the heat had died down. This is an example of why retrieval centres must be outside the financial influence of manufacturers.”
The NHS had to start clawing back the money it lost as a result, said David. “There is never any attempt at financial recovery by the NHS, when a hospital has been sold a batch of defective products.
“If a joint goes wrong and has multiple infections and operations as a result, the NHS just picks up the bill every time – the manufacturers should be made to pay.If a product is proven to be defectively designed or manufacture, rather than having patients dragged through the courts to seek compensation. .”
David was a trainee orthopaedic surgeon when he was asked, in 2007/8, to carry out a clinical review of patients at his hospital trust fitted with the DePuy ASR hip joint. The more he saw and heard, the more alarmed he became.
His ultimate response was to establish ExplantLab, a fully independent research facility with no links to any prosthesis manufacturer.
His team’s collective expertise in the fields of surgery, medicine and bioengineering is employed in assessing the reasons for implant failures, protecting patients from defective devices currently in use and crucially, improving the performance of medical devices in the future.
