Metal on Metal warning (old but ongoing news)

[jancat]

No worries, Dingbat- I would rather know what is going on. It is so sad but true- medicine is not infallible. The disturbing thing to me is that once the manufacturers DO know of a problem, they really should contact every pt and dr and let them know ASAP. That is why these hip and knee registries are so important to me-not only do they provide valuable information for safety and longevity of the implants, they are great for contacting pts if necessary.
BTW- your avatar is a scream!

 

[Josephine]

Don't be sorry. This thread is probably providing people with a lot of real information about the subject, backed up with great little snippets from Bumpa who has been in the manufacturing side of this business almost as long as I was a theatre nurse!

 

[Dingbat7]

Jancat

I suspect companies would rather not recall products or have to pay out compensation, I really wouldn't want to be in the position of having one of those implants, a difficult call do you hope that it won't fail or poison you or do you have surgery and have it removed.
Obviously if symptons a no brainer but do you risk it ????

 

[Josephine]

It's unlikely that scenario would become a reality, dingbat. If the harmful process occurs it will make itself known pretty soon. There are still the majority of MoM hips out there that are asymptomatic, many which have been checked and are fine. This thing, though truly devastating, is still only affecting a small amount of people. But to such a degree that it is unacceptable, obviously. Unlike the PIP breast implant issue, I very much doubt surgeons would be willing to interfere with an asymptomatic and test clear hip because the patient just wants rid of it. Well, not unless the concern had reached the level of a clinical psychosis!

 

[Dingbat7]

I agree but still something to worry about , as one can see from the anxiety of some posters on here re their planned general hip/knee surgery plenty out there who will be concerned and worrying themselves to death , their ears pricking up at every mention in the media .

 

[jancat]

And don't forget all the advertisements from law firms that start with " Have you been injured by....?" or "Did you receive a metal hip implant from ......"
They LOVE to keep the public informed- why it's their civic duty! :wink1:

 

[Dingbat7]

Tell me about it I get cold called from companies telling me I can claim back PPI , I now tell them to hold on a second, put the phone on the table and get myself a drink , returning 5 mins later . I just hope that the National Joint Register is confidential as they will start trawling through that and cold calling M on M patients

 

[Josephine]

Well, it's the same with food stuffs and other things - there's always something that we've eaten for years is now going to kill us! Red meat, fruit and veg that have had certain fertilizers used on them, etc., etc., etc.!

I like the saying "It's mind over matter - if you don't mind, it doesn't matter"!

 

[Bumpa]

Is Smith the author? If not, who is and what was the date of the article?

Josephine, it was: Per Kjaersgaard-Andersen
Chief medical editor of Orthopaedics Today Europe
article published in 2012

 

[Bumpa]

Some metal-on-metal studies are positive, but note that the study refers to a short term one:

Similar short-term results for uncemented large diameter head and cemented THA
Orthopaedics Today Europe, Issue 2

Short-term results of cementless large diameter head total hip arthroplasty were comparable to cemented total hip arthroplasty, according to Finnish researchers who studied the outcomes in a nationwide database. Jari Mokka, MD, of Turku, Finland, is scheduled to present the findings at the 13th EFORT Congress 2012.

“We have a long history with cementless hips as our workhorse,” Mokka told Orthopaedics Today Europe. “As the [large diameter heads (LDH)] were developed, we adopted [metal-on-metal (MoM)] combined with LDH with cementless stems as our primary device for the active patient. We have had very good results with our implant, but we knew that some of the devices had poor results … we wanted to check the nationwide results of all MoM devices.”

This intraoperative image shows reaming the acetabulum for a monoblock MoM acetabular component.

Mokka’s team used data from the Finnish Arthroplasty Register to study the revision risk of 8,059 cementless LDH MoM total hip arthroplasties (THAs) performed from 2002 to 2009 and compared it to the revision risk of 16,978 cemented metal-on-polyethylene THAs done in the same period, according to the abstract. They found no difference in revision risk between the two types of THA procedures, with both having a 0.9 relative risk of revision.

However, in women aged 55 years or older, uncemented LDH MoM THA demonstrated a significantly increased revision risk vs. cemented THA, Mokka and colleagues stated in the abstract. There were likely several factors that contributed to this finding: bone quality and a slightly greater tendency for younger women to have dysplastic hips, Mokka noted.

“Often, women’s hips are more lax than [men’s], so telescoping of the THA is probably more likely to happen and more metal debris will be produced,” Mokka said. “Women also [receive] smaller cups, so head diameter is smaller and point forces are higher. Thus, achieving correct cup inclination and anteversion is even more difficult. There is more stem subsiding and acetabular component loosening in females.”

While women aged 55 years or older should be watched for inferior results following cementless LDH MoM THA, Mokka and colleagues said survivorship of cementless LDH MoM THA was comparable to cemented THA at the nationwide level. Implant design, however, impacted revision rates.

“Not all MoM LDH designs are equal,” Mokka said. “Some of the designs do as well [as] or better than conventional THAs. All MoM LDH designs are very sensitive to component positioning. Conventional THAs are more forgiving in that sense. We should not abandon the whole concept, but we definitely need longer follow-up to be sure.” – by Robert Press

Reference:
Mokka J, Makela K, Virolainen P, et al. Cementless total hip arthroplasty with large diameter metal-on-metal heads — short term survivorship of 8,059 hips from the Finnish Arthroplasty Register. Scheduled to be presented May 23, 16:45-17:45, at the 13th EFORT Congress 2012. May 23-25. Berlin.

 

[Bumpa]

The current British Journal of Bond & Joint Surgery has just published this based on the National Joint Register:
Independent predictors of revision following metal-on-metal hip resurfacing
A retrospective cohort study using National Joint Registry data

1. S. Jameson, MRCS, Research Fellow, National Joint Registry for England and Wales1
2. P. N. Baker, MSc, FRCS(Tr&Orth), Research Fellow, National Joint Registry for England and Wales
3. J. Mason, DPhil, MSc, BSc(Hons), Professor of Health Economics
4. D. J. Deehan, MD, MSc, FRCS(Tr&Orth), Consultant Orthopaedic Surgeon
5. M. R. Reed, MD, FRCS(Tr&Orth), Consultant Orthopaedic Surgeon

Abstract
Modern metal-on-metal hip resurfacing has been widely performed in the United Kingdom for over a decade. However, the literature reports conflicting views of the benefits: excellent medium- to long-term results with some brands in specific subgroups, but high failure rates and local soft-tissue reactions in others. The National Joint Registry for England and Wales (NJR) has collected data on all hip resurfacings performed since 2003. This retrospective cohort study recorded survival time to revision from a resurfacing procedure, exploring risk factors independently associated with failure. All patients with a primary diagnosis of osteoarthritis who underwent resurfacing between 2003 and 2010 were included in the analyses. Cox’s proportional hazard models were used to analyse the extent to which the risk of revision was related to patient, surgeon and implant covariates.

A total of 27 971 hip resurfacings were performed during the study period, of which 1003 (3.59%) underwent revision surgery. In the final adjusted model, we found that women were at greater risk of revision than men (hazard ratio (HR) = 1.30, p = 0.007), but the risk of revision was independent of age. Of the implant-specific predictors, five brands had a significantly greater risk of revision than the Birmingham Hip Resurfacing (BHR) (ASR: HR = 2.82, p < 0.001, Conserve: HR = 2.03, p < 0.001, Cormet: HR = 1.43, p = 0.001, Durom: HR = 1.67, p < 0.001, Recap: HR = 1.58, p = 0.007). Smaller femoral head components were also significantly more likely to require revision (≤ 44 mm: HR = 2.14, p < 0.001, 45 to 47 mm: HR = 1.48, p = 0.001) than medium or large heads, as were operations performed by low-volume surgeons (HR = 1.36, p < 0.001). Once these influences had been removed, in 4873 male patients < 60 years old undergoing resurfacing with a BHR, the five-year estimated risk of revision was 1.59%.

In summary, after adjustment for a range of covariates we found that there were significant differences in the rate of failure between brands and component sizes. Younger male patients had good five-year implant survival when the BHR was used.

 

[Bumpa]

And this has been published in the same issue of JBJS from the Netherlands:
High incidence of pseudotumour formation after large-diameter metal-on-metal total hip replacement
A prospective cohort study

1. B. H. Bosker, MD, Resident in Orthopaedic Surgery
2. H. B. Ettema, MD, PhD, Orthopaedic Surgeon
3. M. F. Boomsma, MD, Radiologist
4. B. J. Kollen, PhD, Epidemiologist
5. M. Maas, MD, PhD, Radiologist
6. C. C. P. M. Verheyen, MD, PhD, Orthopaedic Surgeon

Abstract
Peri-articular soft-tissue masses or ‘pseudotumours’ can occur after large-diameter metal-on-metal (MoM) resurfacing of the hip and conventional total hip replacement (THR). Our aim was to assess the incidence of pseudotumour formation and to identify risk factors for their formation in a prospective cohort study.

A total of 119 patients who underwent 120 MoM THRs with large-diameter femoral heads between January 2005 and November 2007 were included in the study. Outcome scores, serum metal ion levels, radiographs and CT scans were obtained. Patients with symptoms or an identified pseudotumour were offered MRI and an ultrasound-guided biopsy.

There were 108 patients (109 hips) eligible for evaluation by CT scan at a mean follow-up of 3.6 years (2.5 to 4.5); 42 patients (39%) were diagnosed with a pseudotumour. The hips of 13 patients (12%) were revised to a polyethylene acetabular component with small-diameter metal head. Patients with elevated serum metal ion levels had a four times increased risk of developing a pseudotumour.

This study shows a substantially higher incidence of pseudotumour formation and subsequent revisions in patients with MoM THRs than previously reported. Because most revision cases were identified only after an intensive screening protocol, we recommend close monitoring of patients with MoM THR.

 

[Dingbat7]

Nothing like a bit of light reading

 

[Josephine]

Yesterday's follow up meeting (on this December meeting Metal-on-Metal Hip Replacements: Solving The Uncertainties) came to the sorry conclusion that they hadn't progressed very far in conclusions about what, where, when, why and how! The content of the papers was even more microscopic than the previous one! I shall be compiling a report shortly.

 

[Bumpa]

Thanks Josephine, I wonder why I am not surprised - no-one seems to want to make a decision or fund a clinical trial. I look forward to seeing your write-up. There are so many vested interests, clinical journals, surgeons, hospitals, industry - with the patient in the middle!

 

[Bumpa]

Some more information - a cautionary note regarding safe metal ion levels stated by UK Medicines and Healthcare Products Regulatory Agency (MHRA) in http://www.healio.com/orthopedics/

Researchers set safe upper limit metal ion levels for metal-on-metal hip resurfacings
The limits are lower than those of the UK’s Medicines and Healthcare Products Regulatory Agency.

• Orthopaedics Today Europe, Issue 4

An award-winning study by researchers from Belgium identified safe upper limits of 4.6 µg/L for chromium and 4.0 µg/L for cobalt in unilateral metal-on-metal hip resurfacing arthroplasties and 7.4 µg/L for chromium and 5.0 µg/L for cobalt in bilateral procedures.
“Levels higher than [these] established limits were significantly correlated with clinical symptoms, smaller component size, a smaller coverage arc, smaller contact patch to rim distance and a higher cup inclination,” Catherine Van Der Straeten, MD, said. “Females and small head sizes are more at risk of having problematic hips.”
Van Der Straeten presented results of the Otto Aufranc Award-winning study at the Hip Society Specialty Day 2012 in San Francisco. A receiver operating characteristic (ROC) analysis showed that the limits had high specificity and low sensitivity for predicting poor function.
“These upper acceptable limits are lower than the recommended threshold by the Medicines and Healthcare Products Regulatory Agency [in the United Kingdom],” Van Der Straeten said. “But, we had low tolerance for what we call the clinically problematic hip.”

 

[Bumpa]

This paper published in the current issue of the British Bone & Joint Journal tends to support the use of the Birmingham resurfacing hip in men but less so in women
The ten-year survival of the Birmingham hip resurfacing

An independent series

Abstract

Recent events have highlighted the importance of implant design for survival and wear-related complications following metal-on-metal hip resurfacing arthroplasty. The mid-term survival of the most widely used implant, the Birmingham Hip Resurfacing (BHR), has been described by its designers. The aim of this study was to report the ten-year survival and patient-reported functional outcome of the BHR from an independent centre.
In this cohort of 554 patients (646 BHRs) with a mean age of 51.9 years (16.5 to 81.5) followed for a mean of eight years (1 to 12), the survival and patient-reported functional outcome depended on gender and the size of the implant. In female hips (n = 267) the ten-year survival was 74% (95% confidence interval (CI) 83 to 91), the ten-year revision rate for pseudotumour was 7%, the mean Oxford hip score (OHS) was 43 (sd 8) and the mean UCLA activity score was 6.4 (sd 2). In male hips (n = 379) the ten-year survival was 95% (95% CI 92.0 to 97.4), the ten-year revision rate for pseudotumour was 1.7%, the mean OHS was 45 (sd 6) and the mean UCLA score was 7.6 (sd 2). In the most demanding subgroup, comprising male patients aged < 50 years treated for primary osteoarthritis, the survival was 99% (95% CI 97 to 100).
This study supports the ongoing use of resurfacing in young active men, who are a subgroup of patients who tend to have problems with conventional THR. In contrast, the results in women have been poor and we do not recommend metal-on-metal resurfacing in women. Continuous follow-up is recommended because of the increasing incidence of pseudotumour with the passage of time.

 

[Josephine]

I saw that one about HR. Derek McMinn hits it again!

 

[Bumpa]

Here's an update on revisions for Birmingham Hips

Smith & Nephew issues safety notice for Birmingham Hip modular heads

• September 28, 2012

Smith & Nephew Orthopaedics AG in Switzerland has issued an update for use of its
“The indications for use of the Birmingham Hip modular heads is restricted to Birmingham Hip Resurfacing revision surgeries only where a Birmingham Hip acetabular cup is retained and is deemed not to be malpositioned or a contributor to the cause of revision,” Andy Weymann, MD, chief medical officer of the Advance Surgical Devices Division of Smith & Nephew, stated in the field safety notice. He also noted that surgeries using the Synergy uncemented femoral stem were accepted indications for using the modular head.
In the warnings part of the update, the company identified female gender, high implant abduction angle, obesity, avascular necrosis, dysplasia, component size ≤ 46 mm, and combined version (femoral neck anteversion and acetabular cup version) exceeding 45° as risk factors for revision. Contraindications included patients with infection and sepsis. Partial contraindications were patients with osteoporosis, inadequate bone stock, metabolic disorders, vascular insufficiency, neuromuscular disease and muscular atrophy, centers of infection which may spread to the surgical site, insufficient soft tissue around the joint, and metal ion sensitivity, according to the report.
Possible adverse effects to using the modular head include “inflammatory tissue response to high levels of wear debris resulting in peri-prosthetic aseptic lymphocyte dominated vasculitis associated lesions, fluid collections or soft tissue masses,” or pseudotumors, Weymann stated in the notice.
The correction in instructions for use comes from an increase in the average revision rates for the modular heads – all stems in the line now show 1.29 revisions per 100 component years in the National Joint Registry of England and Wales and 1.12 revisions per 100 component years in the Australian Orthopaedic Association’s National Joint Replacement Registry. These rates are higher than the 1% revision rate recognized by the UK National Institute for Health and Clinical Excellence.
Although the rates are higher with the modular heads alone, the report states that, “if combined with the uncemented Synergy stem, the revision rate is 1.07 revisions per 100 observed years which is acceptable and comparable to other clinically successful hip implants on the market.”
“Smith & Nephew’s highest priority is to deliver safe and effective medical technology to benefit patients. As such, we have notified customers and regulatory bodies of a change to the indications for use for the Birmingham Hip Modular Head used during total hip replacement and revision,” Andrew Burns, director of global marketing communications for Smith & Nephew, told ORTHOPEDICS TODAY.
He added, “This modification does not apply to the U.S. market where the Birmingham Hip Modular Head is not approved for use as part of a primary hip replacement procedure. This change does not apply to our BHR resurfacing device, which is performing very well, and is supported by data from several registries and independent, peer-reviewed articles. Going forward, surgeons should now use Modular Head only in conjunction with our uncemented Synergy hip stem in appropriate resurfacing revision cases. This does not change the current practice for patient follow-up care for this product.”
Reference:
http://bhmh.smith-nephew.com/downloads/FieldSafetyNotice.pdf

 

[Bumpa]

There is a great deal of media comment on medical device regulatation in the UK currently. Below is an editorial from the British Medical Journal on this subject. I only hope there is not a knee-jerk reaction to more regulation as I believe there is sufficient now but it is not applied. Expanding the EU to many counties weakens the whole process.

The scandal of medical device regulation
BMJ 2012; 345 doi: (Published 24 October 2012)

Try describing Europe’s system for regulating medical devices and, as Peter McCulloch says in his editorial this week, the response from your audience will be incredulous Read his description and see if you too find yourself asking, “How could this have come about?” It’s a question that now demands urgent remedy. If this was not already clear from recent BMJ investigations (BMJ 2011;342:d2748, BMJ 2012;344:e1410), a new investigation makes it uncontrovertibly so. Working with undercover reporters from the Telegraph newspaper, the BMJ’s Deborah Cohen has exposed a fragmented, poorly regulated, market driven system, with financial incentives to prioritise manufacturers’ interests over those of patients, and with no requirement for clinical evaluation of a device’s safety or effectiveness.

Armed with a fictitious hip implant modelled on one that was recalled on safety grounds in 2010, the reporters approached 14 of the 78 “notified bodies” to which the European Union delegates the job of certifying medical devices. The one to which they eventually submitted their glossy dossier was happy with the design and confirmed that it would approve the device subject to manufacturing documents and a factory visit.

Why did we decide to work with the Telegraph on this “secret shopping” exercise? Firstly, there was a clear and pressing public interest. Secondly, we took the view that the information could not have been obtained by other means. Thirdly, we were reassured by the fact that the BMJ has successfully used fake information to test various systems in the past. As part of a randomised trial published in 1998 (JAMA 1998;280:237-40), we sent out for peer review hundreds of copies of a research paper into which we had inserted errors. The reviewers were not told that the paper was a fake. For this study, as with the fictitious hip implant, we obtained approval for our plans from the BMJ’s ethics committee.

More famously, in 1868, the BMJ’s then editor Ernest Hart placed a newspaper advertisement in which he posed as a father seeking a foster mother for his illegitimate child. His aim was to expose the notorious Victorian practice of baby farming, in which unwanted infants were taken in to be nursed in exchange for payment, but were instead neglected and often killed. The advertisement received 333 replies and sparked a series of articles calling for reform (BMJ 28 March 1868, 301-2). According to the historian Peter Bartrip, the journal’s influence was crucial in achieving legislation.

If the latest undercover operation has similar effect, we will consider the means worthy of the end. Because legislation is what is now urgently needed to protect patients. McCulloch says this must go beyond the tinkering reforms proposed by the EU. Instead, he calls for a system of provisional licensing in which devices could only be marketed if they were being used within clinical studies of their safety and effectiveness. Whatever new system is proposed, he is right to say that it must have patient safety, not trade, at its heart.