Professional Engineering

Poly Implant Prothèse (PIP) would, one suspects, have preferred to stay out of the limelight – if given the choice. The company, a French manufacturer of breast implants, went into liquidation last year following a series of scandals in its native country and overseas over the quality of its products, whose rupture rate had been found to be abnormally high. 

For some of the women with PIP breast implants that failed, the result was inflammation, irritation and hardening of the breast, because of the company’s use of industrial-grade silicone instead of a version designed for cosmetic surgery – and reportedly at 10% of the price of the approved cosmetic type. The French government acted, recommending in December last year that around 30,000 Frenchwomen have their implants removed. In Britain, Sir Bruce Keogh, the NHS medical director, launched a report on the PIP scandal in June, and it is Keogh who has been called on to lead an inquiry into the cosmetic surgery industry announced by the government last month. Up to 40,000 British women have PIP implants.

The problem with the implants was a manufacturing issue, and unfortunately it is by no means an isolated example of medical devices having an adverse effect on patients’ lives. As a result, some are calling for much tougher controls before medical implants are deemed suitable for the market.

One such is Tom Joyce, professor of orthopaedic engineering at Newcastle University. Joyce has campaigned vigorously over problems that some patients are having with large metal-on-metal hip replacements. Owing to wear of the implant and the release of metal into the body, some patients have experienced severe pain, muscle and tissue damage, and attacks on bone. In some cases, the hips had dislocated, leaving the patient in agony. Surgery to repair the damage is difficult, and has the potential to leave patients with long-term problems while relatively young, as the large-head metal-on-metal total hip replacements were originally aimed at patients in their forties
and fifties.

The British Hip Society ruled earlier this year that there should be a moratorium on such implants for now. In Britain, the Medicines and Healthcare Products Regulation Agency (MHRA) has now recommended that patients with large metal-on-metal hip replacements are monitored once a year for the life of the device, instead of for just five years after the operation.

Joyce would go further: “If you look to Holland, no more metal-on-metal hips of any kind will now be implanted, and the Danes have taken the same stance. I think large metal-on-metal has taken a beating. There are a lot of court cases going on in the UK, Ireland, the US and other parts of the world. 

“It remains to be seen what happens, but the companies involved could take a large hit. It might mean, from a financial point of view, that they come to view metal-on-metal replacements as too risky.”

In terms of the regulatory landscape, some are concerned that products such as medical devices come to market too quickly. Part of the problem may lie in the system of “substantial equivalence”, whereby products that exhibit many of the same characteristics as implants already being used in patients are fast-tracked into the healthcare system. The federal Food and Drug Administration (FDA), the US regulator, defines substantial equivalence as a new medical device having the same intended use and common technological characteristics as an existing legally certified device. The whole system needs to be scrutinised more carefully, says Joyce. “There have been implants that have come to market via substantial equivalence that, unfortunately, just haven’t lived up to the promises made for them.”

In Britain, the MHRA is viewed as toothless by some, who argue it follows guidelines that might in themselves be said to be flawed. The FDA, by contrast, is praised for its stringency and relatively conservative approach. Of the MHRA, one expert suggests: “The regulator often uses phrases such as ‘ensuring the safety of the patient’ – to my mind it doesn’t always ensure the safety of the patient.”

John Wilkinson, director of devices at the agency, says the furore over the PIP implants, and the concerns over large metal-on-metal hip replacements, could help in bringing the whole area of new medical technology under greater scrutiny. “I think the prominence of both issues will ultimately prove to be helpful, because it’s shone a light on this area of activity. As long as we get a measured response, I don’t think it’s going to be damaging. 

“It shouldn’t be of interest just to patients. I think it is an area that requires vigorous attention. The fact that issues such as the PIP implants have come to the surface could be helpful in terms of the long-term debate we need to have.”

Wilkinson is pragmatic about the strictures within which the regulators must operate: “Very few things work perfectly in this world, so I think it’s about facing up to the issues and challenges in a realistic manner.

“It would be dangerous to go down an excessively precautionary route, because we will deprive patients of the sorts of technologies that could be transformational for their lives.” Joyce, meanwhile, acknowledges: “The aim has been to bring good and innovative devices to market quickly for patient benefit – and really no one can disagree with that.”