All-Metal-Hips; We expect not many patients are demanding them right now
It’s incredible how these bandwagons gain momentum isn’t it? Although less so when the enormity of the problem and its impact on a significant patient group is factored in. Perhaps it’s also unsurprising that after the coverage of last week’s British Hip Society Meeting, the repercussions are now exercising clinicians and the medical and non medical media around the world.
The issue, as if you need reminding, is that in recent days the UK MHRA has issued guidance suggesting that patients with implanted metal-on-metal hips above a certain femoral head diameter (36mm) and all metal-on-metal hips from DePuy’s ASR range should undergo a regime of lifelong testing for signs of wear or failure.
Following MHRA issuing guidance, the British Hip Society(BHS) met in Manchester last week and debated the subject again at great length, issuing this document in conjunction with the British Orthopaedic Association(BOA), explaining its own position.
Now we begin to see the reaction. While in UK there still remain a number of metal-on-metal implants being implanted, the situation has gone a step further in Denmark, where they have been banned outright. And in India, as reported here by the Times of India, the headline is that “Metal Hip Replacements May Lead To Cancer”, despite the specific comment in the BHS/BOA release and indeed in the article’s own copy stating that “there is absolutely no evidence of that (developing cancer as a consequence of the prosthesis) at this stage” (ie the 7 years over which the National Joint Registry has collected data).
Inadequate regulation and untrammeled commercialism?
British Medical Journal editor Dr Fiona Godlee has reportedly said that: ‘Hip replacements are one of the great successes of modern medicine. But a combination of inadequate regulation and untrammelled commercialism has caused actual and potential harm for large numbers of patients around the world.’
Is that really the case? Not according to the British Hip Society who’s statement clearly supports the concept of innovating, in this case to introduce a class of product (all-metal hips) which were intended to “benefit young patients, because the traditional implant was more likely to fail over time and require a complex revision operation.” Not much untrammeled commercialism going on there as surgeons strive to find better solutions for a particular group of needy and unserved patients. Indeed the piece directly refutes the criticism that the use of these devices represented a “large uncontrolled experiment”.
Could stronger regulation have prevented problems?
It’s undeniably a disaster, but if the companies didn’t see it coming, the surgeons didn’t see it coming and the regulators didn’t see it coming, then what kind of regulatory regime would have spotted it? In advance of launch we believe it’s pretty difficult to beef the regulations up in a meaningful way, which leaves us with post-marketing surveillance, which has to be in the spotlight. Except that again we’re again faced with a dilemma; The media is suggesting blind eyes were turned to the impending doom at a very early stage, when the reality, as again pointed out in the BHS/BOA positioning statement is that “The information on failures of Metal on Metal implants accumulated slowly – as is always the case“. Joint registry data from Australia was really first to the scene with its concerns, followed by UK’s equivalent. Given the now mature nature of the UK Joint Registry, would the trend be picked up better now? Possibly, but not before patients had been implanted in enough numbers for the trend to be spotted, leaving the accusation of treating those patients as guinea pigs intact.
Be careful for what you wish
While few would now question the need for tighter regulation, equally we have to be sure that new rules would prevent such a recurrence and not be such a deterrent to innovators that the incentive to innovate is stopped dead and do not pander to the popular media as an alternative to featuring a degree of pragmatism. It’s all tricky stuff in medical devices. Animal models are often ineffective, especially in simulating large joints and increasingly ethically undesirable not to say expensive. Unlike pharmaceuticals which have a direct chemical effect, devices often need to be looked at from many perspectives which are truly difficult to simulate, leaving us with some form of controlled and balanced assessment of risk. With a hip replacement, no amount of theoretical modelling nor bench top testing will render a device undergoing the rigours of life in pretty much permanent supportive motion, completely and predictably wrinkle-free. So engineers and developers work from the standpoint of what they know, and endeavour to address problems that currently exist in order to have products which will only be successful if they have patient benefits. As the BHS/BOA statement says, “no manufacturer sets out to design a bad implant for patients”.
Source: medlatest staff, Times of India, www.dr.dk, BOA.ac.uk