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A successful product very often attracts people who will make it even better. One of the first total hip joint models developed by the English surgeon John Charnley was a huge success, at least in England. With the death of its designer in 1982, all further improvements of the Charnley's original model stopped. But the development of total hip joints did not stop in 1982. Thus, after 1982 there emerged many attempts to produce an improved "version" of the "gold standard" as Charnley's total hip was also named. (Thanks to patent protection of the original Charnley's total hip model, outright copying was without reach). One such attempt has its place in the history of total hip replacement.

The 3M Worldwide Company and total hips??

 For most of us the 3M Company is known as the manufacturer of the Scotch Office tape.

It is less known that this global company, grounded in 1902 as the Minnesota Mining and Manufacturing Company (you see the 3M in the name?), also manufactured total hip joints in the 1980’ and 1990’s.

The official company’s history, however, does not mention this short sojourn of the 3M company on the highly volatile market for new models of total joints.

This short involvement, however, has its place in the history of total joints. First, it demonstrated how a manufacturer took responsibility for the failure of his product; second, it led to the foundation of the British national joint registry.

 

 3M becomes involved in total hips

 The Company’s involvement with total hips production started somewhere in the mid 1980’s. In an advert published in 1984 in The Journal of Bone and Joint Surgery, the Orthopaedic Products Division of the company offered a total hip joint called TC-32 and a cup component called MMS Acetabular Cups.  Both products are described as “Designed to last”.

This advert also says that “You can rely on 3M to meet your total hip needs – both now and in the future”. I cannot assess the reliability of just this promise; I did not find any reports about the success or failure of these 3M total hip products.

On the other hand, the length of the future of the 3M’s total hips is known; from then on it lasted just for further13 years. 

The Company’s engagement with total hips namely ended in 1997 when the production of the 3M Capital total hip models in the Company’s English factory at Hallaby was stopped. 

The press release said that the termination of the production was done “for  economic reasons” because the Company was “a too little player” on the total joint global market, which might be true. The 3M Capital hip had only 2% market share of all total hip models implanted in Great Britain under this period.

 

The 3M Capital Hip fails

 What the press release, however, did not reveal was the fact that the termination of the 3M’s production at Hallaby was preceded by catastrophic failure of this total hip model in Great Britain.  Indeed, the 3M Capital Hip failure was often cited as an example of catastrophic failure of total hips in “modern” time.

The catastrophic failure of the 3M Capital Hip in England successively grew into an open scandal. The leading British Medical Journal wrote with typical understatement in 1998 “The hazard warning issued this month by the Medical Devices Agency in Britain on the 3M Capital hip system evoked emotion…”

 

Action on highest places

 The 3M Capital hip failure did much more than evoke emotion. Eventually the British Parliament and the Health Minister Lord Hunt were involved in the investigation of the  3M Capital Hip failure.

There was reason for this engagement. The use of the 3M Capital Hip was approved by the newly established Medical Device Agency (MDA), so the failure tainted this government agency too. At the conference with the MDA in 1998, the medical device industry “expressed fears that the recent problem with the 3M hip implant case was causing many to question the efficacy of the Medical Device Directive”.

 Moreover, even the European Commission for approval of medical devices was involved because its agency granted the 3M Capital hip the EC seal of approval. Thus the 3M Capital Hip was approved the status of a “safe” product.

The scrutiny of what went wrong with the 3M Capital Hip was commissioned to the committee of scientists from the Royal College of Surgeons of England – means for it were provided by the 3M Company. 

 

Taking responsibility.

You might view providing Company’s money to an independent official institution (Royal College) to examine failure of one of Company’s  own products  as a means to covertly influence the conduct of the inquiry. But I don't think so.

I view it simply as an act of “taking responsibility” of the consequences of the failure of Company's product. Moreover so because in a comprehensive program the 3M Health Care Company undertook to finance the examination of all patients who received the 3M Capital Hip and to pay the costs of any necessary revision surgery and of all other necessary care. This means to take responsibility.

We have seen similar financing of  failures of total joints by other companies whose products also failed catastrophically. The difference is, however, how it was done. Either in a litigation process (Inter-op total hip, Sulzer), or outside the court (and outside the public insight - Oxinium total knee, Smith&Nephew).

In both cases the science of total joints did not benefit from these two catastrophic failures for the future. There was no independent examination of their causes.

 

The failure incites foundation of a national-wide total joint registry

 The 3M Capital Hip failure was, on the other hand, one of the rare cases in the history of total joints when a catastrophic failure proved to be decidedly beneficial for the future patients.

It was so that during the evaluation of all aspects of this failure there emerged the idea of an early “warning system”. The English scientists asked: Was it possible to see the approaching catastrophe early on, before it reached catastrophic dimensions? Was it possible to stop the use of the 3M Capital Hip early, before it was implanted in too many patients and caused so much suffering to many of them?

Yes, answered the scientists in 2000, it was possible to stop the sales of 3M Capital hip early on but for that there should be an early warning system. Such warning system would, however, need registration of all total hip operations and also the registration of their failures on the national level.

The idea of the national-wide registry of all total hips and knee operations and registry of their failures in England was thus born.

It then took some three years of technicalities before the National Joint Registry for England and Wales started collecting data on 1^st April 2003. (http://www.njrcentre,org.uk) 

For the bureaucratic National Health System ruling in England it was a quick march.

 

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Details of the whole 3M Capital Hip history.

 

The 3M Capital Hip – the "improved" copy of a successful total hip model

The Capital Hip was marketed as a cheaper variant of the successful Charnley total hip model. Because of its similarity with the Charnley total hip model, the 3M Capital total hip got its approval by the British Medical Devices Agency and also the European Commission's  CE mark of approval. With this double approval the use of 3M Capital Hip joint soon spread to totally 95 British hospitals.

The obvious idea of the producer of 3M Capital hip was to make it so similar to the Charnley hip system as the patent rights would allow and then add some perceived improvements in materials that appeared since the late 1970’s when the development of the Charnley’s total hip was finished.

Marketing it as a "cheaper variant" made the 3M Capital Hip really attractive for the poor British National Health Care system.

 

The 3M Capital hip – the enormous diversity versus the simplicity of the original

 

 All Charnley’s total hip models were made from stainless steel and were monoblock (the ball and the stem components were put together at the fabrication).

Against the Charnley total hip model the 3M Capital Hip offered a real multitude of combinations of materials and forms.

Then you could choose either monoblock or a modular system (for “modular” see also the chapter Function of a total hip prosthesis / modular system). You could also choose the stem component made from titanium alloy or from stainless steel and when it came to the ball component you had three choices of material: stainless steel, titanium nitride hardened titanium, or cobalt-chrome alloy. There were, however, no specific, registered names for all these combinations, only batch a series numbers.

Add to this diversity the fact that the 3M Capital Hip was cemented and the surgeons could use two different bone cements with quite different characteristics. All this diversity produced a nightmare when it came to present statistics of the results.

 

The spread of 3M Capital hip and the first failures

In the period from1991 through to 1997 totally 4669 3M Capital Hips were implanted in 95 Hospitals in Great Britain.

The first adverse review was published already in 1995 on the meeting of British surgeons in Aberdeen in Scotland. The surgeons at the University of Nottingham's Department of Orthopaedic and Accident Surgery were namely uneasy about the early failures of the 3M Capital hip and the head of the Department professor Wallace appointed doctor Massoud with special responsibility to follow the results of the 3M Capital Hip.

In his report to the meeting doctor Massoud presented the disquieting facts. Two years after surgery, 16% of 3MCapital Hips were already radiologically loose. At that time in 1995, the British surgeons already had implanted 900 Capital Hips.

Were the further operations with Capital Hips stopped then, the failure would be limited. But nothing such happened. Instead  the failures were seen mainly as caused by wrong cementing technique.

The 3M Company reacted swiftly, it produced new tools for cementing of the femoral stem and issued  guidance to surgeons how to use them. In retrospect one may say that it was a swift reaction against a wrong culprit.

 

 

Picture: Diagram of development of the 3M Capital Hip catastrophe 

 

Titanium and bone cement do not like to be in contact

Titanium alloy and bone cement don’t like each other, the “soft titanium” wears off against the “hard” bone cement. Thus, improvement of the cement technique did not remove the cause of 3M Capital Hip failures. Even after the improvement of cementing technique of the 3M Capital Hip, the titanium stems were still in close contact with bone cement. See also the chapter Quest for titanium hips.

Doctor Massoud’s investigations appeared in the press first two years later, in 1997, when the 3M Capital hip was already retracted from the market (Massoud 1997). Medical journals lag considerably as source of actual information on total joints.

The 3M Company also undertook “extensive survey” of surgeons using this model. The results of this survey demonstrated “5% failures as of January 1996”  which was considered by 3M Health Care Company to be “within industry standards” according to the official report of the National Health Authority (http://www.nao.org.uk/publications/nao_reports/9900417.pdf)

The MDA initially did not react. This changed when in July 1996 the British television was sending a documentary demonstrating high rates of failure of the  Capital Hip in different British hospitals. After watching this document that the MDA started its own inquiry;  a rather curious kind of scientific information gathering.

Whereas this MDA inquiry continued at a peaceful tempo, the 3M Health Care company stopped  in March 1997 “marketing 3M Capital Hip for commercial reasons.”

The government Agency’s slow reaction

How reacted the MDA who was the gatekeeper for "safe" medical devices on his withdrawal? In August 1997 the MDA officially notified the 3M Health Care company that "the enquiries about 3M Capital Hip were complete, with no further action required"!

All was thus quiet until the agency’s officials at a conference in January 1998 learned of “unconfirmed” failure rates of 3M Capital as high as 20% after two years at some clinical centers. First when these “oral reports were confirmed”, the MDA eventually ssued a hazard note in February 1998 advising clinicians "to stop using the 3M Capital hip in view of its reported high failure rates”.

Really a quick and curious reaction from an official government agency: hazard note was issued on a total hip model whose high failure rates were made clear in a television program two years ago and who was retracted by the manufacturer from the market one year ago.

 

What can we learn from this history?

One response to the failure of the Capital hip is to insist that only "old" well tested total hip designs should be used. Total hips such as the proven Charnley prosthesis, when inserted into patients in the sixth decade of life, will survive for 10 years in 90% of cases, whereas the 3M Capital Hip failed five times more often.

The argument for using only " old " tested designs of total hips implies that they are so good there is no need  to improve on them. This argument does, however, not apply to drugs, nor to total hips either.

When proposing this argument we must also remember that the longevity of any total hip depends not only on prosthetic design but also on surgical technique, or rather on the surgeon’s experience.

The need for improved total hip joints is clear, especially when it comes to younger patients. Younger patients have long life expectancies and require more durable prostheses that will last for 30 years or more. We still do not have such total joint devices.

From this point of view, using new, previously unproven models of total joints on patients is ethically permissible. Under condition that all necessary laboratory experiments have been done with them and that all experiments also demonstrated the advantages of the new model.

Such laboratory testing was obviously lacking in the case of 3M Capital Hip model. Chief executive of the British MDA Alan Kent who was criticized for his acting in the  market approval of 3M Capital hip later acknowledged that “there were perceived weaknesses with the (testing) system".

It appeared later for example that finite element analysis of 3M Capital Hip  would expose quickly the bad mechanical characteristics of the titanium made components of the 3M Capital Hip ( Jansen 2005). (Finite element analysis is a computer based method that tests the mechanical performance of a studied device on the computer screen, so to say).

A high politician’s view & promises: 

Health Minister Lord Philip Hunt said in a parliamentary debate in 2000: “Unfortunately, medical devices do sometimes have problems. This implant (3M Capital Hip) was introduced before the new Medical Devices Regulations, which now control implants, came fully into effect in 1998. …The Department of Health and NHS are working on an ongoing basis to ensure that we learn as much as possible from the past to improve patient care in the future, and the National Joint Registry will be a key part of this." 

Currently (Nov 2005), 2400 new records on individual total hip and total knee operations are entered each week into the NJR's (National Joint Registry) database that already contains data about 93 000 total hip and total knee operations since its start in 2003.

It sound so good. But due to politicians' involvement, the NJR is at present virtually unable to single out the bad total hip and knee models. The patients are namely free to withdraw  their personal code numbers from the NJR database. Including the personal code number in the database might violate the patients' "personal integrity" say the politicians. What a politically correct nonsense!

  Without this personal code it is impossible to link  together the failure and the original operation of a specific total joint model.  As yet only 20% of all patients are willing to "give up their personal integrity" and have their personal code numbers included in the database. That means that for the majority of total joint operations their long term outcomes and failures will remain unknown.

Contrary to Lord Philip Hunt's promises, with 80% of all total hip and knee joint operations "unlinkable" the NJR database cannot be "a key part for improving the care" for patients who need total joint replacement. (Gregg 2005)

What was wrong with the 3M Capital hip anyway?

 With such magnitude of possible combinations of the 3M Capital Hip components the statistic analysis is a nightmare. It is, however, obvious that not all these combinations have catastrophic results.

The 3M Capital Hip models closest to the copied Charnley hip model had about equally low rates of failures by llosening – as the original, i.e.  < 1% of them failed annually according to the report from the Royal College of Surgeons (2001).

The highest failure rates by loosening  were observed in 3M Capital Hip models made from titanium alloys and models that had femoral ball made from titanium nitride hardened alloys.  This was nothing unique for the 3M Capital Hip, also in other total hip models the titanium made femoral components fare badly when cemented. Similarly, the scientist and surgeons discovered on other total hip models that the nitrogen hardening of the surface of titanium femoral balls was a bad idea. These failure prone devices disappeared silently from the market.

It thus seems that it was the choice of material for fabrication of 3M Capital Hip models that was the ultimate cause of failure. Was the 3M Capital Hip catastrophe preventable?  

The enthusiasm for titanium was widespread in the 1980’s among the surgeons. The first warnings suggesting that bone cement in contact with titanium is a bad combination appeared, however, already five years before the introduction of the 3M Capital Hip on the English market (Sarmiento 1985). Why did not the responsible scientists and  surgeons take notice from it?

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References:

Editorial BMJ:  1998;316: 644

.Gregg, PJ. National Joint Registry England— Launch of 2nd annual report. Presented at the British Orthopaedic Association Annual Congress. Sept. 20-23, 2005. Birmingham,

D. Janssen, at al.: Finite-element analysis of failure of the Capital Hip designs. Journal of Bone and Joint Surgery - British Volume, Vol 87-B;  1561-1567

Massoud SN et al.: Early femoral loosening of one design of cemented hip replacement. J Bone Joint Surg – Br  1997; 67-B: 603 -8

Sarmiento A, Gruen T.: Radiographic analysis of low modulus titanium-alloy femoral total hip component. J Bone Joint Surg-Am 1985;  67-A: 48-56