Metal on Metal warning (old but ongoing news)

I think they did but only from the POV of mechanics. You have to remember that these metals had been in use in human medicine for years in the form of bone plates and screws and intramedullary nails without any problems so they were reckoned to be inert. As surgeons in London last Dec kept saying "Who knew there was this other side to biomechanics which is only now being revealed because of the advanced technology in searching for them." NOW we know but we still only know a part of the story. It really is a can of worms.

The habit of interchanging femoral stems from one manufacture with heads from another, for instance, has been going on for some time and where there was a mismatch in size, the manufacturers have made it possible by supplying trunnion sleeves. Now it seems that the sleeves themselves may be one problem, as I said in my notes. Did you read those?
 
I did have a browse but to be honest as I am not in the situation where I have to decide to have MoM so didn't take it all in.

Find it strange they can mix and match.
 
Well, they thought they could but it's emerging that doing it is responsible for at least some of these issues.

So it actually turns out that they can't!
 
This was reported in the British Medical Journal of February 29, 2012:

Around 49 000 UK patients with metal-on-metal hip implants with a femoral diameter of 36 mm or more will need follow-up tests for the rest of their lives, the Medicines and Healthcare Products Regulatory Agency has announced in what could prove to be the biggest medical device dispute for years.
The agency issued a medical device alert on the hip implants at an emergency briefing yesterday, called to coincide with the release of the findings of an investigation by the BMJ and BBC Newsnight, which revealed problems with metal-on-metal implants caused by metal ions leaking into the body.
 
Further, this article "On-going problems with metal-to-metal hip implants" was also published at the end of February 2012- it gives a summary:
Major advances in total hip replacement have occurred since the prosthesis was first developed by Charnley in the 1960s. Yet substantial concerns currently exist over newer hip implants as a result of rising revision rates and increased risk of cancer.
By the 1980s revision rates of total hip replacements were as low as 20% after 15 years of follow-up. Throughout this era, the main focus was reducing aseptic loosening and osteolysis, which were thought to reduce lifespan. Various combinations of materials have been used in attempts to improve the lifespan of prostheses, which comprise three main types: metal on plastic, metal on metal, and ceramic on ceramic. The first word in the name refers to the head and the second name the cup (metal on plastic is a metal femoral head against a plastic acetabular cup).

Hip resurfacing systems use metal to replace the surface of both joints, preserving the femoral head. Conventional total hip replacement requires complete removal of the femoral head with the prosthesis secured into the upper part of the femoral shaft. Hip resurfacing became popular for younger patients, in whom a quicker return to function and a more active lifestyle are priorities, but it is a challenging operation requiring specialised training and practice.

In 2000, the National Institute for Health and Clinical Excellence (NICE) guidance on selection of prostheses for primary hip replacement and resurfacing set a benchmark revision rate for conventional hip replacement of 10% or less at 10 years. At the time NICE stated, “Surgeons should ensure that patients considering MoM [metal-on-metal] hips resurfacing arthroplasty understand that less is known about the medium-to-long term safety and reliability of these devices or the likely outcome of revision surgery than for conventional hip replacements.”

However, over a decade later, evidence on safety is still lacking. A 2011 systematic review of 29 studies of hip resurfacing found no studies fulfilled the NICE 10 year benchmark of 10%. Indeed, a 2007 technology assessment of hip resurfacing concluded “the peer-reviewed literature had not kept pace with changes in hip resurfacing technology.” Problems with hip devices emerged in July 2008 when the Zimmer Durom acetabular component was voluntarily recalled because of much higher failure rate than expected.

And in 2010 DePuy had to voluntarily recall its ASR hip prostheses (one for resurfacing and one for total hip replacement) because of failure rates of about one in eight. A year later the UK regulator, the Medicines and Healthcare Products Regulatory Agency (MHRA), had to send letters to surgeons to notify them “that some of the 40 000 patients who received the metal-on-metal DePuy ASR hip implants never received the recall notice.” At the British Orthopaedic Association’s 2011conference, further concern was expressed that large diameter metal-on-metal devices from other manufacturers were also showing higher than expected failure rates, especially in women. To add to all this, complaints of “metal poisoning” are growing among patients with DePuy Pinnacle metal-on-metal hip implants.
 
since the prosthesis was first developed by Charnley in the 1960s
:tantrum2: Why do they do this - it was NOT Charnley! Was Ken McKee in the 50s!
 
Out of interest would those effected be able to sue ????
I suppose the argument against would be , the industry didn't know the risk.

Would the NHS replace the joints if requested ???
 
Yes, if the classic signs of this problem are found, I believe the patient has a case. Plenty of law firms touting for business on it!

The NHS will replace the implants if the need arises. This is because the vast majority of people with MoM hips aren't having any problems and are perfectly happy with their hip. Even those with the ASR aren't necessarily having problems. However, there have been cases where an asymptomatic hip was revised purely on psychological grounds because the patient was so stressed about it.
 
I will get my solicitor on standby........!!

Positive thinking, there will be no problems, there will be no problems, there will be no problems....... can't do anything about it so why worry until it is an issue, that's the way I see it.
 
Josephine, re history of arthroplasty.

1822 Anthony White performed the first successful arthroplasty of the hip. A nine year old boy had fallen downstairs and the femoral head had become displaced, resting far back on the ilium. White removed the femoral head 2 inches below the greater trochanter. A fibrous union developed between the femur and pelvis. This was the first recorded osteotomy.

1938 Philip Wiles, in London, replaced both the femoral head and acetabulum with a stainless-steel total hip replacement. The acetabular component was fixed with two screws, while the femoral head was secured by a bold passing through the neck of the femur. Although the prosthesis generally disintegrated, probably due to different manufacturing histories and compositions, Wiles can be considered the originator of metallic total hip replacement.

1956 GK(Ken)McKee produced the first widely accepted total hip replacement. However, his work started in 1940, at Norwich, where he produced a prototype model, which was never used in patients. Finding fixation to be the major problem a lag screw was used for the acetabular component fixation in 1951. This model was derived from the screw arthrodesis. Between 1956 and 1960, following a visit to America and FR(Fred) Thompson, he started using the Thompson prosthesis for replacement of the upper end of the femur. However, the head size was decreased and a cloverleaf cup with a coarse screw, to give a captive head effect yet allowing a bay for flexion was used. By 1960 the acetabular component was modified to utilise cement fixation by having small studs on its convex surface. By 1965 the Thompson stem had been modified to feature a more spherical head, a more slender neck, and the acetabular component rim was reinforced.

By the way McKee couldn't get any of the manufacturers, at first, to help him - Howmedica, as it then was, in America said that total hip replacement would never catch on. So McKee paid for his own dies for the prostheses to be done by Deloro-Stellite in Canada.
 
Thanks for the detail, Bob. I knew about Wiles, of course - McKee was his registrar. But good to have the dates and all. I'm still ticked off they keep citing Charnley as the 'inventor' of the hip replacement though. Still, such things have have happened frequently in medicine - much like to two men who invented anaesthesia (or rather "which one invented anaesthesia"!). Or Sauerbruch (1927) who came up with the idea of pressure differential chamber that would keep the lungs inflated while he operated inside the chest but was pipped at the post by an American army anaesthetist who devised the notion of positive pressure ventilation via an endotracheal tube which was so much more reliable.

As you know, Charnley's coup was that he insisted on surgeons going to him for training before Thackray's were allowed to sell them the prostheses. Thus he was able to dictate a certain standard of application unlike McKee who demonstrated a few, published a report in the BMJ(?) and ended up with his device being savaged because there were so many failures. All of which leaves me with the enduring belief that there are no inherently bad implants, only poor surgical technique.

Howmedica, as it then was, in America said that total hip replacement would never catch on.
And I love that! Kinda comes on board with Decca who famously said the Beatles would never catch on! :rotfl:
 
Josephine on this subject: the start of hip joint replacement generally were prioneered by three surgeons at NON TEACHING HOSPITALS - Ring at Redhill, Charnley at Wrightington and McKee at Norwich. I know they are now teaching hospitals but not then. I was not aware that McKee was Wiles registrar - there now, even I don't know everything!
 
Have either of you ever thought of going on Mastermind with this as your specialist subject , you would win hands down :heehee:

Hip replacements 1938 to present
 
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I was not aware that McKee was Wiles registrar - there now, even I don't know everything!
I only know that because he used to mention a Peter and also once told JWF how, when he got the job as his registrar, someone said to him "Are you going to go work for that idiot who plays around with hips?"!

dingbat, I think you may have sussed that Bob and I spent our careers actually living this history. They were the Golden Years.
 
OK, on a more serious note - latest from the UK Government's Agency on this subject:
MHRA updates advice for metal-on-metal hip replacements

The Medicines and Healthcare Regulations Agency has issued updated advice to surgeons that states patients with metal-on-metal hip replacements with head diameters of 36 mm or more need to be monitored every year for the life of the replacement.

The new advice is an update to previous Medicines and Healthcare products Regulatory Agency (MHRA) advice issued in April 2010, which stated patients with 36 mm metal-on-metal hip replacements only needed to be monitored for a minimum of 5 years after the operation, according to an MHRA news release.

The updated advice is included in a new MHRA Medical Device Alert, issued to clinicians for the management of patients with these hip implants to minimize the risk of complications and further procedures.

“As a precautionary measure, we have today issued updated patient management and monitoring advice to surgeons and doctors that they should annually monitor patients for the lifetime of their metal-on-metal total hip replacements that are sized 36 millimeters or more because this particular type of hip replacement has a small risk of causing complications in patients,” MHRA clinical director Susanne Ludgate, FRCR, FRACR, stated in the release. “By monitoring patients every year, any complications will get picked up earlier and more complex surgery on the patient can be avoided.”

The new recommendations are a response to findings from an MHRA advisory group assembled to investigate the management of patients with soft tissue swelling associated with metal-on-metal hip implants, according to the release. The group meets regularly to evaluate new scientific advice and observations from clinicians.

Reference: www.mhra.gov.uk
 
Interesting. Thanks, Bob.
 
Published today in the Lancet

The Lancet, Early Online Publication, 13 March 2012
doi:10.1016/S0140-6736(12)60353-5
LINK

Failure rates of stemmed metal-on-metal hip replacements: analysis of data from the National Joint Registry of England and Wales

Alison J Smith MSc, Prof Paul Dieppe FRCP, Kelly Vernon BSc, Martyn Porter FRCS, Prof Ashley W Blom PhD
on behalf of the National Joint Registry of England and Wales
Summary

Background
Total hip replacement (THR) is extremely common. Some prostheses fail, particularly in younger patients, and need to be revised, most commonly for loosening secondary to wear or dislocation. Surgeons have tried to address these problems by implanting large diameter metal-on-metal bearing surfaces. Our aim was to assess if metal-on-metal bearing surfaces lead to increased implant survival compared with other bearing surfaces in stemmed THR and, additionally, if larger head sizes result in improved implant survival.

Methods
We analysed the National Joint Registry of England and Wales for primary hip replacements (402,051, of which 31,171 were stemmed metal-on-metal) undertaken between 2003 and 2011. Our analysis was with a multivariable flexible parametric survival model to estimate the covariate-adjusted cumulative incidence of revision adjusting for the competing risk of death.

Findings
Metal-on-metal THR failed at high rates. Failure was related to head size, with larger heads failing earlier 3·2% cumulative incidence of revision for 28 mm and 5·1% for 52 mm head at 5 years in men aged 60 years.

5 year revision rates in younger women were
6·1% for 46 mm metal-on-metal compared with 1·6% for 28 mm metal-on-polyethylene.

By contrast, for ceramic-on-ceramic articulations larger head sizes were associated with improved survival: 5 year revision rate of 3·3% with 28 mm and 2·0% with 40 mm for men aged 60 years.

Interpretation
Metal-on-metal stemmed articulations give poor implant survival compared with other options and should not be implanted.

All patients with these bearings should be carefully monitored, particularly young women implanted with large diameter heads.

Since large diameter ceramic-on-ceramic bearings seem to do well we support their continued use.
 
Josephine, well done - I was about to post the National Joint Register statement when I noticed you had beaten me to it! This subject is almost down and dusted now apart from those with metal-on-metal with large head sizes (the device, not the forum member) who must be very concerned.
 
Do you have a subscription to the Lancet? I'd surely like to read the article.
Am faintly hoping it might be reproduced in JBJS but probably not. :(
 
No, I don't but I find that once registered you can access their publications. This report is encouraging for some metal-on-metal patients with the BHR device:

Smith & Nephew release study results for metal-on-metal hip implants
Smith & Nephew released the results of a study for its Birmingham Hip Resurfacing (BHR) System. The 10-year study tracked the progress of the first 400 BHR patients in the UK and found that 99% were satisfied or extremely satisfied with the BHR procedure, according to a news release.

The study, conducted at the request of the FDA, included 258 males and 142 females with an average age of 53.2 years. In addition to patient satisfaction, the study also reported an Oswestry Modified Harris Hip Score averaging 92.5 points, an implant survival rate of 95.9% and a radiographic success rate of 99.7%, according to the release.

The distinctive metallurgy and design geometry both contribute to the success of the BHR system. The geometry replicates the hip’s natural ability to pull the body’s joint fluids into the space between the ball and socket. This reportedly creates a natural fluid layer between the femoral head and cup and decreases the metal wear between the two surfaces.

“These results further exemplify why the BHR Hip is unlike any other metal-on-metal implant,” John Soto, senior vice president for Smith & Nephew’s Global Hip Franchise, stated in the release. “Not only does the BHR Hip offer all the advantages of hip resurfacing, including bone-conservation, greater range of motion and decreased risk of dislocation, but it does so while maintaining implant survivorship rates that are on par with, or in some patient populations even better than, traditional total hip replacement which has long been considered the most successful orthopaedic surgical procedure for relieving chronic pain.”
 

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