I had the privilege of getting some great questions from Howard last night and I thought that they, along with my answers would be good “food for thought” for all of us. Here they are – you judge:

 

Hi Howard, you are such an inspiration and incredibly humble – considering all you have been through I wonder at times how you keep going! The site is part of my “anger management” – an old boss of mine once said – “don’t get mad, just get even”!!!

I am trying to figure out the answers you are after too. Here are my current thoughts after having read hundreds of articles:

 

Question 1: Is plastic on plastic better than metal on metal ?

Metal on Plastic doesn’t seem to have the same toxicity issues as the plastic, not the metal, is eroded. The plastic particles are much larger than the metal particles and do cause osteolysis. However, it seems that these stay localized and there is not the same issue as with MoM. Metal on Ceramic – I think this will end in heart ache for a number of people – the cobalt chrome is still ground away and looking at the data on the new ones on the market, cobalt levels are elevated. The new DePuy one is reviewed here https://earlsview.com/2011/06/25/ceramic-on-metal-total-hip-replacement/ on the Blog When it comes to the Smith and Nephew Oxinium & metal, I think you have the same potential for problem & if you search under Oxinium on my blog you will see that it is oxidized Zirconium metal – i.e., zirconia – which even in very small amounts is very “osteolytic”, if there is such a word – i.e., will cause marked osteolysis – tissue and bone breakdown. Look at my Blog article here https://earlsview.com/2011/06/24/is-oxinium-going-to-be-safer-maybe/Ceramic on ceramic has its own issues too – squeaking, fracture etc.

Question 2: Can friction of these components create plastic shavings?

Absolutely and without a doubt in the world. Friction is well proven in the scientific literature to cause plastic “shavings” in metal on plastic hip joints – and osteolysis is the predictable result.

Question 3: Have the newest hips been tested adequately: providing realistic data?

The newest hips on the market seem to be a reinvention of materials that have been around for ages – the new DePuy ceramic on metal – the ceramic component has been around for ages and is made by a third party… or a DePuy subsidiary with another name! The DePuy device has only been tested for two years on a small same of about 400 from memory and I think it is way to early to say this is safe – it may take 4 – 6 years to evidence the same problems as their infamous ASR & Pinnacle hips. The Oxinium material Smith and Nephew are touting in their new hip replacements has been used in their knee implants for about 10 years – and it has had its share of troubles. There seems to be a lot less of complaints in the press and scientific literature with the hip replacements from other companies and I suspect that it is because of a couple of things – the first is that they are not the market leaders and so the volumes are less – hence given the percentages that apply, there are less absolute sufferers if something goes wrong – if DePuy had not been a market leader then it may have taken much longer to come to the attention of the general population – that is why you and I with Smith & Nephew devices don’t get the same press – there are less of us! The bottom line is that most new hips are a variation on a theme, like another mouse trap, and so they are “grandfathered” into use by the 510k process or something similar, depending what country you are in. No the data is NOT adequate from a patient’s perspective, but statistically, the good outweighs the bad as long as those affected is lower than 10% – and they get to hide behind the fact that with age, we all have problems and some of these can be used to rule out data that would potentially make them look bad.

Question 4: Do the manufactures of the newest and greatest hip devices have 1 year, 2year, 3, 4, 5, 6 years results?

(Data taken from a random sample of hospitals, orthopaedic surgeons, US, and rest of the world) and does this data include the best to the absolute worse patient results, including rashes,nausea, low grade fevers, back pains, limping,sleepless nights caused from pain, groin pain etc.)In a word – NO!!! All companies are required to undertake post-market studies – and now that DePuy has made just a mess of people’s lives, the requirements are becoming more stringent. But they try to measure as few as possible and keep the data collection as tight as possible.

Last night I blogged the FDA info about metal on metal hips onto my site – they are a bunch of conservative statistical fence-sitters; there is clear evidence that the cobalt chrome levels are unsafe and toxic in many of these cases and yet they waffle on about no definitive studies to prove this is the case – what about the 93,000 people suffering all around the world… duh…

Like most commercial ventures, none of these companies likes to take the heat and so they always try to explain it away – like Stryker’s Trident & DePuy – blame the surgeon and the positioning of the acetabular cup. None of the data you would expect to be collected – or sensibly should be collected, is collected – there is rough attempt at this with the scoring they use (forget the name) but it is very narrow and “outliers like you and me” get missed or excluded.

Question 5: Have these devices been tested by any family members of the CEO’s of these large companies?

I suspect – yes and no – but we will never know as that would be classified. If DePuy had done this, then there would have been a lot less harm done – but then they have their problems too – it is not politic to experiment on your own employees – but it seems OK to experiment on the general “hip replacement public” at large! Your advice is well received – it is our faith, friends and family which keeps us going each day – otherwise we would quickly tire of the great experiment of biological existence! Earl

 

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