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BMJ Hip Coverage

Client Attorney Privileged/Attorney Work Product/At Request of Counsel

Online Sources

Metal-on-Metal Hip Replacement Devices Implanted after 2006 have a High Revision Rate
May 6, 2016 | Reuters Health
By Marilynn Larkin

Certain metal-on-metal (MoM) hip replacement devices implanted after 2006 have an “unacceptably high” revision rate, due mainly to manufacturing problems, according to a new study.
Hip implant in Pounds 343m Texas lawsuit criticised by British doctors over 'failure rate'
Apr 29, 2016 | Press Association
By Jane Kirby

BRITISH doctors have published evidence of an "unacceptably high revision rate" for a hip implant that has been the subject of a multi-million pound US lawsuit.
One in three hip implants were the wrong size, study finds
Apr 28, 2016 | Daily Telegraph
By Claire Newell, Lyndsey Telford, Edward Malnick and Luke Heighton

A “significant” number of hip replacements surgically implanted into British patients were the wrong size, a scientific study has found.
British doctors highlight 'unacceptably high revision rate' for hip implant
Apr 28, 2016 | Press Association

British doctors have published evidence of an "unacceptably high revision rate" for a hip implant that has been the subject of a multi-million pound US lawsuit.
Best-selling hip implants are 'unacceptably' prone to failure, doctors warn, and 'could leak metal into the bloodstream'
Apr 29, 2016 | Mail Online
By Ben Spencer

Hip implants given to 12,000 people in Britain are ‘unacceptably’ prone to failure, doctors have warned.
Brits with THIS type of hip replacement could be 10 times more likely to need more surgery
Apr 29, 2016 | Daily Mirror
By Andrew Gregory

Thousands of Brits who have had hip replacements since 2006 may need further surgery, experts have warned.
Metal-on-metal hip replacements implanted since 2006 'more prone to failure'
Apr 28, 2016 | ITV News

New research has suggested that metal-on-metal hip replacements implanted since 2006 are more prone to failure and that when they fail they "fail in a much nastier way".
Doctors raise alarm over hip implants
Apr 29, 2016 | The Times

Doctors have published evidence of an "unacceptably high" failure rate for a hip implant that has been the subject of a multimillion-pound US lawsuit.

Trade

Study Reveals More Than One-Third of Hip Implants Made by Johnson & Johnson (JNJ)'s DePuy Synthes Were the Wrong Size
Apr 29, 2016 | BioSpace

A “significant” number of hip replacements surgically implanted into British patients were the wrong size, a scientific study has found.
Metal Hip Replacements Implanted Since 2006 More Prone To Failure
Apr 29, 2016 | Sciences 20

Metal on metal hip replacements implanted since 2006 are more prone to failure and the need for further surgery, finds research looking at revision rates at one hospital trust for the DePuy Pinnacle device, and published in the online journal BMJ Open.
Metal hip replacements implanted since 2006 more prone to failure
Apr 29, 2016 | Science Codex

2006 are more prone to failure and the need for further surgery, finds research looking at revision rates at one hospital trust for the DePuy Pinnacle device, and published in the online journal BMJ Open.
Daily Recap
Apr 29, 2016 | STAT Pharmalot, Pharmalitte
By By Ed Silverman

Included in the daily roundup of health relate new. Relevant sections pasted below.
Metal Hip Replacements Implanted Since 2006 More Prone to Failure
Apr 29, 2016 | Medical Design Technology

Metal on metal hip replacements implanted since 2006 are more prone to failure and the need for further surgery, finds research looking at revision rates at one hospital trust for the DePuy Pinnacle device, and published in the online journal BMJ Open.
MoM Hip Implant Failure Linked to Manufacturing Variation
May 2, 2016 | Medscape
By Diana Phillips

An "unacceptably high" risk for failure and revision surgery associated with a commonly used metal-on-metal hip implant may be partly attributable to the use of components that were outside of stated manufacturing tolerances, investigators report in a study published online April 29 in BMJ Open.

Regional Outlets

British doctors highlight 'unacceptably high revision rate' for hip implant
Apr 29, 2016 |
By Bailwick Express

British doctors have published evidence of an "unacceptably high revision rate" for a hip implant that has been the subject of a multi-million pound US lawsuit.
British doctors highlight ‘unacceptably high revision rate’ for hip implants
Apr 29, 2016 | Evening Express

British doctors have published evidence of an “unacceptably high revision rate” for a hip implant that has been the subject of a multi-million pound US lawsuit.

Full Text of Stories Below

Client Attorney Privileged/Attorney Work Product/At Request of Counsel

Online Sources

Metal-on-Metal Hip Replacement Devices Implanted after 2006 have a High Revision Rate

May 6, 2016 | Reuters Health

By Marilynn Larkin

http://www.the-hospitalist.org/article/14689/
Certain metal-on-metal (MoM) hip replacement devices implanted after 2006 have an “unacceptably high” revision rate, due mainly to manufacturing problems, according to a new study.
To determine risk factors for revision in patients implanted with the commonly used DePuy Pinnacle MoM hip prostheses, the researchers identified all patients at the Stockton-based hospital who were implanted with a 36 mm MoM Pinnacle hip in conjunction with an S-ROM or Corail uncemented stem. They then identified only patients with components that had been implanted by either of the two senior authors of the study, Dr. Raj Logishetty or Dr. Antoni Viral Francis Nargol.
Implantations were performed from 2003-2009 and patients were monitored yearly. From 2007-2011, as awareness of the risk of adverse reactions to metal debris (ARMD) from MoMs increased, the hospital offered patients who developed symptoms blood metal ion testing and as-needed ultrasound scanning. From 2011 onward, given the widespread problems reported with MoMs, the hospital recalled all Pinnacle MoM patients for examination.
A total of 489 MoM Pinnacle hips had been implanted into 243 women and 191 men. Of these, 352 patients attended the MoM recall clinics and 64 died during the study period (mean
followup, about 7.5 years). For the purposes of survival analyses, those who did not attend the recall clinics were assumed to have well-functioning prostheses.
A total of 71 hips were revised — an “unacceptably high” rate, according to the authors. All but one were carried out for ARMD, with one revision for a loose cup. Prosthetic survival rate for the cohort as a whole was 83.6% at nine years.
In 53 revisions (75%), “copious amounts” of fluid were found, and in 32 (45%), it was noted to be under pressure or had fistulated through the capsule. No abnormal fluid was identified at revision in only one case.
The researchers noted obvious damage to the abductor musculature in 38 cases. They documented a moderate-to-severe aseptic lymphocyte-dominated vasculitis-associated lesion on examination of retrieved tissues in 36 cases (51%). In 13 cases (19%), they found metallosis with no identified lymphocytic infiltration.
The majority of explanted devices showed signs of taper junction failure. A significant number of devices were found to be manufactured out of their specifications — a finding that was confirmed by an analysis of a wider data set from the Northern Retrieval Registry.
Risk factors for revision were bilateral MoM prostheses, smaller Pinnacle liners, and implantation in 2006 or later. Women were found to be at greater risk of early device failure. However, shell sizes and bearing diameters confounded the analyses, and liner size and/or earlier year of liner manufacture were determined to be greater threats to prosthetic survival than gender. The authors suggest that this analysis be repeated with input from an additional registry.
Dr. Langton, who is involved in litigation related to the Pinnacle device, told Reuters Health by email, “We have essentially shown that one of the major health care/orthopedic product manufacturers sold a product to surgeons and health care systems on the basis (that it was a) technologically advanced precision-engineered device, and it wasn’t precision-engineered.”
He added, “the product was produced in the same factories as (DePuy’s) other failed product, the ASR, which was . . . marketed on the same premise.”
Mindy Tinsley, senior director, Communications and Public Affairs at DePuy Synthes Franchise, refuted the study findings. “We stand behind the strong record of safety and effectiveness of the (Pinnacle) ULTAMET Metal-on-Metal,” she told Reuters Health by email.
She added that “there are no manufacturing problems” with the device and noted that DePuy “questions the validity of the . . . paper given significant flaws in how it was conducted.” According to Tinsley, “measurements taken following an accepted international standard at the DePuy UK manufacturing facility” showed the device liners “were manufactured within specification.”
Dr. Mark W. Hungerford, director of Joint Replacement and Reconstruction at Mercy Medical Center in Baltimore, told Reuters Health by phone, “One study does not make or break anything in science. There have been issues in the field about MoM and early failure rates or not. That’s a serious issue being looked at by a lot of people. This is one more study showing a problem, but it’s not a definitive one.”
With respect to patients, “the obligation is no different than for any orthopedic device,” said Dr. Hungerford, who has not used the Pinnacle device. “All can fail, all need to be monitored for failure on a regular basis, and if problems arise, they need to be dealt with.”
The authors reported no funding. Dr. Langton, Dr. Nargol, and coauthors Dr. Thomas Joyce and Dr. Nick Cooke are retained experts for plaintiffs in ongoing MoM litigation. Dr. Langton and Dr. Nargol have worked with the U.S. Department of Justice in litigation involving DePuy.

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Hip implant in Pounds 343m Texas lawsuit criticised by British doctors over 'failure rate'

Apr 29, 2016 | Press Association

By Jane Kirby

http://www.pharmacychoice.com/news/article.cfm?Article_ID=1550055
BRITISH doctors have published evidence of an "unacceptably high revision rate" for a hip implant that has been the subject of a multi-million pound US lawsuit.
Almost 12,000 Britons have received the Pinnacle metal-on-metal hip implant made by DePuy, part of Johnson & Johnson, according to official joint registry data.
Now researchers say they have operated on patients with "black tissue" caused by "high levels of chromium and cobalt" and that patients have suffered pain.
DePuy was forced to recall a different implant (the ASR) in 2010 after it was linked to muscle and bone damage and neurological issues.
Johnson & Johnson was ordered by a Texas federal jury last month to pay about $500 million (Pounds 343m) to five people who said they were injured by the Pinnacle implants. The jury decided they were defectively designed and DePuy had failed to warn of the risks.
Johnson & Johnson has said the company will appeal that verdict. Thousands more people have launched action against the company.
Dr David Langton, of the University Hospital of North Tees, who led the latest study, said his team had told DePuy in the UK, and the Medicines and Healthcare products Regulatory Agency (MHRA), of problems with the Pinnacle over several years.
He said: "These Pinnacle implants were advised for younger patients who were very active. We've found that they fail at a higher rate than conventional ones, but they fail in a much nastier way."
A spokeswoman for DePuy said: "We stand behind the strong record of safety and effectiveness of Ultamet (Pinnacle) metal-on-metal in reducing pain and restoring mobility for patients suffering from chronic hip pain.
"There are no manufacturing problems with Ultamet as the Langton paper suggests. Further, we question the validity of the Langton paper given significant flaws with how it was conducted."
Credit: By Jane Kirby, Press Association Health Editor

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One in three hip implants were the wrong size, study finds

Apr 28, 2016 | Daily Telegraph

By Claire Newell, Lyndsey Telford, Edward Malnick and Luke Heighton

http://www.telegraph.co.uk/news/2016/04/28/machines-in-wrong-sized-hip-implants-were-used-for-8-years-manuf/
A “significant” number of hip replacements surgically implanted into British patients were the wrong size, a scientific study has found.
Research carried out by orthopaedic surgeons and engineers discovered that over a third of the devices analysed fell out of the size limits set by the company making them, with devices implanted after 2006 most affected.
The paper, published in the British Medical Journal Open, describes how many of the Pinnacle metal-on-metal components made by Depuy were “found to be manufactured out of their specifications”.
The authors of the study concluded that production issues “may play a significant role” in hip replacements failing in patients and that devices implanted into women had a higher failure rate.
The disclosure will add to concerns about the safety of implants and will be likely to increase pressure on the regulators who oversee the industry.
According to the authors, the Pinnacle is the most commonly used metal-on-metal implant in the world and has been used for more than 180,000 people
In January, The Daily Telegraph revealed how hip implants that have left thousands of British people in pain were manufactured incorrectly at a factory in Yorkshire.
Depuy said there were no safety issues, but refused to answer detailed questions about what action they took to address concerns raised.
However, the study in BMJ Open suggests manufacturing problems could have affected patient health by leading to device failure.
The study looked at 489 metal-on-metal Pinnacle hips implanted into 434 patients. Of these, 352 patients attended recall clinics and 71 hip replacements were revised. The patients were from one hospital trust in northern England.
The study examined patients with 36mm replacements implanted by two of the report’s authors. The devices were examined by one of the authors at Newcastle University and North Tees Implant Centre.
After examining the 71 hip implants that formed part of the study, the authors state that “a significant number of devices were found to be manufactured out of their specifications”.
They say that this was confirmed by work carried out at the Northern Retrieval Registry – an organisation that examines devices that have been removed from patients after they have failed.

A spokesman for Depuy said that the paper was “inconsistent with the results of many peer-reviewed studies that were conducted with more scientific rigor and transparency” and that components sold were within specification.

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British doctors highlight 'unacceptably high revision rate' for hip implant

Apr 28, 2016 | Press Association

http://www.dailymail.co.uk/wires/pa/article-3564703/British-doctors-highlight-unacceptably-high-revision-rate-hip-implant.html
British doctors have published evidence of an "unacceptably high revision rate" for a hip implant that has been the subject of a multi-million pound US lawsuit.
Almost 12,000 Britons have received the Pinnacle metal-on-metal hip implant made by DePuy, part of Johnson & Johnson, according to official joint registry data.
Now researchers say they have operated on patients with "black tissue" caused by "high levels of chromium and cobalt" and that patients have suffered pain.
DePuy was forced to recall a different implant (the ASR) in 2010 after the devices were linked to muscle and bone damage and neurological issues.
In March this year, Johnson & Johnson was ordered by a Texas federal jury to pay around 500 million US dollars (£343m) to five people who said they were injured by the Pinnacle metal-on-metal hip implants.
The jury decided the Pinnacle hips were defectively designed and that DePuy had failed to warn the public about their risks.
Johnson & Johnson has said the company will appeal against that verdict. Thousands more people have launched action against the company.
Dr David Langton, from the University Hospital of North Tees, who led the latest study, said his team had told DePuy in the UK, and the Medicines and Healthcare products Regulatory Agency (MHRA), of problems with the Pinnacle over several years.
He said: "These Pinnacle implants were advised for younger patients who were very active.
"We have found that they fail at a higher rate than conventional ones but they fail in a much nastier way.
"You get very high levels of chromium and cobalt around the hip and that can go into the bloodstream. There can be black metal-stained tissue.
"The Pinnacle was put into people in lot bigger numbers than the ASR - up to about 500,000 people worldwide.
"What we've found is that some of our patients have come back with lots of pain. The implants have then been taken out by us.
"In total myself, I've looked at between 150 and 200 Pinnacle implants."
He added: "We've reported this and had several meetings with DePuy and the MHRA.
"We physically handed the implants to DePuy and showed them how they were not the right size and how they were going to fail.
"In my opinion, they should never have left the factory.
"Hips should fail at no more 0.5% per year but we found the Pinnacle has been failing at a significantly higher rate than that."
Dr Langton said his team believed up to 20,000 people in the UK had received the implants.
The study, published in the journal BMJ Open, found in particular that Pinnacle metal on metal implants manufactured and implanted since 2006 were more prone to failure.
The team looked specifically at the long-term performance of the 36mm Pinnacle metal-on-metal hip.
Over the study period, 489 metal-on-metal Pinnacle hips were implanted into 434 patients.
Of these, 352 patients attended future clinics and 71 metal hips required surgical removal and replacement.
There was a revision rate of 16.4%, which researchers described as "unacceptably high".
The study found that before 2006, only five out of 43 hips (12%) failed to meet the manufacturer's product specification.
But after 2006 more than a third (36% or 43 out of 118) failed to comply.
Furthermore, in over 40% of cases, the taper surface - a key part of the implant - was defective.
The authors said this was significantly associated with the excessive release of metal particles.
Staining of bodily tissue had also occurred in around one in five (19%) cases.
In 2012, the MHRA said patients who had undergone large head metal-on-metal hip replacements should be monitored annually for life.
They should have blood tests to check for metal ions, and MRI scans if necessary, it said.
No comment was immediately available from Johnson & Johnson or the MHRA.
An MHRA spokeswoman said: "MHRA take allegations of device non-conformities seriously and will investigate these with manufacturers when sufficient evidence is presented to MHRA.
"We are, however, unable to comment on regulatory matters which may involve a manufacturer due to confidentiality restrictions within the medical device regulations.
"The majority of patients who receive hip implants have well-functioning hips and are at a low risk of developing any serious problems.
"MHRA continues to monitor the performance of all hip implants in the UK though its post market surveillance system.
"We also work closely with our expert orthopaedic advisory group which includes representatives from the British Orthopaedic Association, the British Hip Society and the National Joint Registry for England, Wales, Northern Ireland and Isle of Man to assess any new scientific evidence and we will take safety action if needed to ensure that patients are protected from unsafe hip implants."
Law firm Leigh Day said it was acting on behalf of 333 clients who were claiming compensation from DePuy for having to undergo early revision surgery following a Pinnacle implant.
A three-month trial in the High Court is due to begin in October 2017.
Spokeswoman Sarah Moore said: "We consider that this study is highly significant to the individuals whom we represent.
"The study reports that after analysing hundreds of explanted Pinnacle components, the doctors involved have found that a significant number of devices were found to be manufactured out of their specifications."
"This is a very serious allegation that we will continue to investigate with our expert team.
"If this allegation is proven, this may be a further factor in explaining why so many individuals have suffered severe injuries and early revision following their implantation with these products.
"The evidence of an 'unacceptably high revision rate' should put more pressure on DePuy to come to the negotiating table rather than our clients having to drag them through the courts."

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Best-selling hip implants are 'unacceptably' prone to failure, doctors warn, and 'could leak metal into the bloodstream'

Apr 29, 2016 | Mail Online

By Ben Spencer

http://www.dailymail.co.uk/news/article-3564906/Best-selling-hip-implants-unacceptably-prone-failure-doctors-warn-leak-metal-bloodstream.html
Hip implants given to 12,000 people in Britain are ‘unacceptably’ prone to failure, doctors have warned.
Experts have published evidence which suggests people given the best-selling Pinnacle hip implant are at high risk of needing surgery to have them removed.
The metal-on-metal hip implant, made by Johnson & Johnson’s prosthetics company DePuy, is the most-used in the world.
But it is already subject to a multi-million pound US lawsuit, and now further concerns have emerged in the UK.
Surgeons in Britain say they have operated on patients with ‘black tissue’ caused by chemicals leaching out of the metal joint.
They say the implants are too often made slightly too big or too small, with the resulting friction causing chromium and cobalt to rub off into the blood stream.
DePuy was forced to recall a different implant - the ASR - in 2010 after the devices were linked to muscle and bone damage.
In March this year, Johnson & Johnson was ordered by a Texas federal jury to pay $500 million (£340million) to five people who said they were injured by the Pinnacle joints.
Johnson & Johnson has said the company will appeal against that verdict but thousands more people have launched action.
According to the National Joint Registry, 11,871 people in England and Wales have received the Pinnacle implant.
Study leader Dr David Langton, whose work was published last night in the medical journal BMJ Open, said: ‘We have found that they fail at a higher rate than conventional ones but they fail in a much nastier way.
‘You get very high levels of chromium and cobalt around the hip and that can go into the bloodstream. There can be black metal-stained tissue.
‘What we’ve found is that some of our patients have come back with lots of pain. The implants have then been taken out by us.
‘In total myself, I’ve looked at between 150 and 200 Pinnacle implants.’
Dr Langton, from the University Hospital of North Tees, added: ‘We’ve reported this and had several meetings with DePuy and the MHRA.
‘We physically handed the implants to DePuy and showed them how they were not the right size and how they were going to fail. In my opinion, they should never have left the factory.
‘Hips should fail at no more 0.5 per cent per year but we found the Pinnacle has been failing at a significantly higher rate than that.’
The research team found that Pinnacle metal on metal implants manufactured and implanted since 2006 are more prone to failure.
They found a ‘revision rate’ - in which further surgery is needed - in 16.4 per cent of cases, which they said was ‘unacceptably high’.
The team looked specifically at the long-term performance of the 36mm Pinnacle hip.
Over the study period, 489 metal on metal Pinnacle hips were implanted into 434 patients.
Of these, 352 patients attended future clinics and 71 metal hips required surgical removal and replacement.
The study found that before 2006, 12 per cent of implants failed to meet the manufacturer’s product specification, meaning they were slightly the wrong size or shape.
But after 2006 more than 36 per cent failed to comply.
And in over 40 per cent of cases, the taper surface - a key part of the implant - was defective.
The authors said this was significantly associated with the excessive release of metal particles.
A spokesman for the MHRA said last night: ‘MHRA take allegations of device non-conformities seriously and will investigate these with manufacturers when sufficient evidence is presented to MHRA.
‘The majority of patients who receive hip implants have well-functioning hips and are at a low risk of developing any serious problems.’
A spokesman for DePuy insisted that the company stood behind the ‘strong record of safety and effectiveness’ of its hip implants, and claimed there were ‘significant flaws’ with the way Dr Langton’s research was conducted.
She added: ‘There are no manufacturing problems … as the Langton paper suggests. The paper is also inconsistent with the results of many peer-reviewed studies that were conducted with more scientific rigor and transparency.’

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Brits with THIS type of hip replacement could be 10 times more likely to need more surgery

Apr 29, 2016 | Daily Mirror

By Andrew Gregory

http://www.mirror.co.uk/news/uk-news/thousands-hip-replacement-patients-could-7855484
Thousands of Brits who have had hip replacements since 2006 may need further surgery, experts have warned.
More problems in the manufacturing process in the last decade are to blame.
Metal on metal hip replacements involving the DePuy Pinnacle device implanted since 2006 are more prone to failure and the need for further surgery, according to new research published in journal BMJ Open.
Researchers looked specifically at the long term performance of the 36mm Pinnacle metal on metal hip. This is the most commonly implanted metal hip in the world.
They wanted to uncover any risk factors associated with early failure and any need for further surgery.
The use of metal on metal hips has plummeted over the past five years, but hundreds of thousands remain in place.
Experts reviewed the progress of around 500 Brits fitted with metal on metal total hip replacements at one hospital trust in northern England, and followed them for an average of 7.5 years after the procedure.
In all, 71 metal hips required surgical removal and replacement, which the researchers describe as “unacceptably high”.
Before 2006, only five out of 43 hips - 12% - failed. But after 2006 more than a third - 36% - failed.

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Metal-on-metal hip replacements implanted since 2006 'more prone to failure'

Apr 28, 2016 | ITV News

http://www.itv.com/news/2016-04-28/metal-on-metal-hip-replacements-implanted-since-2006-more-prone-to-failure/
New research has suggested that metal-on-metal hip replacements implanted since 2006 are more prone to failure and that when they fail they "fail in a much nastier way".
Dr David Langton, from the University Hospital of North Tees, who led the latest study said that when doctors operated on patients whose implants had failed some had found "black metal-stained tissue" around where the new joint had been put in.
He said: "We have found that they fail at a higher rate than conventional ones but they fail in a much nastier way.
"You get very high levels of chromium and cobalt around the hip and that can go into the bloodstream. There can be black metal-stained tissue."
Research findings published in the BMJ Open journal looking at the 'DePuy Pinnacle device' stated the hip replacement "has not lived up to clinical expectations" and suggested it could lead to a greater need for further surgery in patients.
A spokeswoman for DePuy stated that "there are no manufacturing problems" with their devices and questioned the validity of the Langton paper given what the company said were "significant flaws with how it was conducted".
Which replacement hips were looked at in the study?
The focus of the study was the 36 mm Pinnacle metal-on-metal hip which consists of a metal 'ball' which acts as the top of the thigh bone and fits inside a metal liner which acts as the replacement socket.
After studying 434 patients (243 women and 191 men), who between them had been fitted with 489 metal-on-metal hips, over a seven and a half year period researchers noted an "unacceptably high" 71 of those metal hips required surgical removal and replacement.
According to researchers implantation from 2006 onwards also carried a significantly higher risk of failure, a factor that it was suggested could be due to "an increasing tendency from this date to manufacture devices outside of their intended product specification".
How many people could be affected by the findings?
Data from the National Joint Registry for England and Wales for 2014 indicates that 11,871 metal on metal Pinnacle hips have been implanted.

Researchers calculated that could mean as many as 180,000 people around the world could be walking around with these hips.

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Doctors raise alarm over hip implants

Apr 29, 2016 | The Times

http://www.thetimes.co.uk/
Doctors have published evidence of an "unacceptably high" failure rate for a hip implant that has been the subject of a multimillion-pound US lawsuit.
One in three of the Pinnacle metalon-metal implants, made by DePuy, part of Johnson & Johnson, failed to meet the product specification, according to the study in the BMJ Open journal. Last month Johnson & Johnson was ordered by a Texas federal jury to pay about $500 million (£343 million) to five people who said they were injured by the implants, which have been used in almost 12,000 British patients.
In the latest study a team led by David Langton, from the University Hospital of North Tees, looked at the performance of Pinnacle hips implanted into 434 patients. Those manufactured and implanted after 2006 were most prone to failure, with a "revision rate" of 16.4 per cent.
"Hips should fail at no more than 0.5 per cent per year but we found the Pinnacle has been failing at a significantly higher rate," Dr Langton said. The law firm Leigh Day is acting on behalf of 333 patients who are claiming compensation from DePuy. A trial in the High Court is scheduled for October next year.
The company recalled another implant, the ASR, in 2010 after it was linked to muscle and bone damage and neurological issues.
No comment was immediately available from Johnson & Johnson.

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Trade

Study Reveals More Than One-Third of Hip Implants Made by Johnson & Johnson (JNJ)'s DePuy Synthes Were the Wrong Size

Apr 29, 2016 | BioSpace

http://www.biospace.com/News/study-reveals-more-than-one-third-of-hip-implants/417494
A “significant” number of hip replacements surgically implanted into British patients were the wrong size, a scientific study has found.
Research carried out by orthopaedic surgeons and engineers discovered that over a third of the devices analysed fell out of the size limits set by the company making them, with devices implanted after 2006 most affected.

The paper, published in the British Medical Journal Open, describes how many of the Pinnacle metal-on-metal components made by Depuy were “found to be manufactured out of their specifications”.

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Metal Hip Replacements Implanted Since 2006 More Prone To Failure

Apr 29, 2016 | Sciences 20

http://www.science20.com/news_articles/metal_hip_replacements_implanted_since_2006_more_prone_to_failure-171602
Metal on metal hip replacements implanted since 2006 are more prone to failure and the need for further surgery, finds research looking at revision rates at one hospital trust for the DePuy Pinnacle device, and published in the online journal BMJ Open.
A higher rate of manufacturing issues since 2006, with more than a third of hips manufactured outside the stated specifications, may be to blame, suggest the researchers.
They looked specifically at the long term performance of the 36 mm Pinnacle metal on metal hip--the most commonly implanted metal hip in the world--in a bid to uncover the risk factors associated with early failure and the need for further surgery.
The use of metal on metal hips has plummeted over the past five years, but "hundreds of thousands" remain in place. A better understanding of the factors associated with a higher risk of failure would not only help those patients fitted with them, but could also inform the design of future products, say the researchers.
They reviewed the progress of 434 patients (243 women and 191 men) fitted with 489 metal on metal total hip replacements at one hospital trust in northern England, and monitored for an average of 7.5 years after the procedure.
In all, 71 metal hips required surgical removal and replacement, adding up to a revision rate of 16.4%, which the researchers describe as "unacceptably high."
A metal on metal hip consists of a metal 'ball,' which acts as the top of the thigh bone (femoral head). This fits inside a metal liner, which acts as the replacement socket.
Total replacement of both (bilateral) hip joints and thinner liners were risk factors for failure at nine years.
But implantation from 2006 onwards also carried a significantly higher risk of revision, possibly because of the increasing tendency from this date to manufacture devices outside of their intended product specification, say the researchers.
Before 2006, only five out of 43 hips (12%) failed to meet the manufacturer's product specification. But after 2006 more than a third (36%; 43 out of 118) failed to comply.
Furthermore, in over 40% of cases examined the taper surface was defective. The taper surface describes the inside of the femoral head that is attached to the femoral stem--the part that anchors the implant in the thigh bone. This defect was significantly associated with excessive metal particle release.
Abundant metal staining of tissues visible to the naked eye (metallosis) had occurred in around one in five (19%) cases.
Metal hips implanted into women were also more likely to fail, but the researchers caution that twice as many women as men had bilateral hip replacements, and when the findings were analysed according to sex and liner thickness, thinner liners had the greater impact.
Data from the National Joint Registry for England and Wales for 2014 indicate that 11,871 metal on metal Pinnacle hips have been implanted, prompting the researchers to calculate that 180,000 people around the world are now walking around with these hips. These patients might be at risk of early revision surgery, they suggest.

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Metal hip replacements implanted since 2006 more prone to failure

Apr 29, 2016 | Science Codex

http://www.sciencecodex.com/metal_hip_replacements_implanted_since_2006_more_prone_to_failure-181369
2006 are more prone to failure and the need for further surgery, finds research looking at revision rates at one hospital trust for the DePuy Pinnacle device, and published in the online journal BMJ Open.
A higher rate of manufacturing issues since 2006, with more than a third of hips manufactured outside the stated specifications, may be to blame, suggest the researchers.
They looked specifically at the long term performance of the 36 mm Pinnacle metal on metal hip--the most commonly implanted metal hip in the world--in a bid to uncover the risk factors associated with early failure and the need for further surgery.
The use of metal on metal hips has plummeted over the past five years, but "hundreds of thousands" remain in place. A better understanding of the factors associated with a higher risk of failure would not only help those patients fitted with them, but could also inform the design of future products, say the researchers.
They reviewed the progress of 434 patients (243 women and 191 men) fitted with 489 metal on metal total hip replacements at one hospital trust in northern England, and monitored for an average of 7.5 years after the procedure.
In all, 71 metal hips required surgical removal and replacement, adding up to a revision rate of 16.4%, which the researchers describe as "unacceptably high."
A metal on metal hip consists of a metal 'ball,' which acts as the top of the thigh bone (femoral head). This fits inside a metal liner, which acts as the replacement socket.
Total replacement of both (bilateral) hip joints and thinner liners were risk factors for failure at nine years.
But implantation from 2006 onwards also carried a significantly higher risk of revision, possibly because of the increasing tendency from this date to manufacture devices outside of their intended product specification, say the researchers.
Before 2006, only five out of 43 hips (12%) failed to meet the manufacturer's product specification. But after 2006 more than a third (36%; 43 out of 118) failed to comply.
Furthermore, in over 40% of cases examined the taper surface was defective. The taper surface describes the inside of the femoral head that is attached to the femoral stem--the part that anchors the implant in the thigh bone. This defect was significantly associated with excessive metal particle release.
Abundant metal staining of tissues visible to the naked eye (metallosis) had occurred in around one in five (19%) cases. .
Metal hips implanted into women were also more likely to fail, but the researchers caution that twice as many women as men had bilateral hip replacements, and when the findings were analysed according to sex and liner thickness, thinner liners had the greater impact.

Data from the National Joint Registry for England and Wales for 2014 indicate that 11,871 metal on metal Pinnacle hips have been implanted, prompting the researchers to calculate that 180,000 people around the world are now walking around with these hips. These patients might be at risk of early revision surgery, they suggest.

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Daily Recap

Apr 29, 2016 | STAT Pharmalot, Pharmalitte

By By Ed Silverman

https://www.statnews.com/pharmalot/2016/04/29/medivation-sanofi-abbvie/
More than one-third of hip implants made by Johnson & Johnson’s DePuy unit were the wrong size and have may have played a “significant role” in failed hip replacements, The Telegraph writes, citing new research in the British Medical Journal Open. Known as the Pinnacle, the device is the most commonly used metal-on-metal implant in the world and has been used for more than 180,000 people.

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Metal Hip Replacements Implanted Since 2006 More Prone to Failure

Apr 29, 2016 | Medical Design Technology

http://www.mdtmag.com/news/2016/04/metal-hip-replacements-implanted-2006-more-prone-failure
Metal on metal hip replacements implanted since 2006 are more prone to failure and the need for further surgery, finds research looking at revision rates at one hospital trust for the DePuy Pinnacle device, and published in the online journal BMJ Open.
A higher rate of manufacturing issues since 2006, with more than a third of hips manufactured outside the stated specifications, may be to blame, suggest the researchers.
They looked specifically at the long term performance of the 36 mm Pinnacle metal on metal hip--the most commonly implanted metal hip in the world--in a bid to uncover the risk factors associated with early failure and the need for further surgery.
The use of metal on metal hips has plummeted over the past five years, but "hundreds of thousands" remain in place. A better understanding of the factors associated with a higher risk of failure would not only help those patients fitted with them, but could also inform the design of future products, say the researchers.
They reviewed the progress of 434 patients (243 women and 191 men) fitted with 489 metal on metal total hip replacements at one hospital trust in northern England, and monitored for an average of 7.5 years after the procedure.
In all, 71 metal hips required surgical removal and replacement, adding up to a revision rate of 16.4%, which the researchers describe as "unacceptably high."
A metal on metal hip consists of a metal 'ball,' which acts as the top of the thigh bone (femoral head). This fits inside a metal liner, which acts as the replacement socket.
Total replacement of both (bilateral) hip joints and thinner liners were risk factors for failure at nine years.
But implantation from 2006 onwards also carried a significantly higher risk of revision, possibly because of the increasing tendency from this date to manufacture devices outside of their intended product specification, say the researchers.
Before 2006, only five out of 43 hips (12%) failed to meet the manufacturer's product specification. But after 2006 more than a third (36%; 43 out of 118) failed to comply.
Furthermore, in over 40% of cases examined the taper surface was defective. The taper surface describes the inside of the femoral head that is attached to the femoral stem--the part that anchors the implant in the thigh bone. This defect was significantly associated with excessive metal particle release.
Abundant metal staining of tissues visible to the naked eye (metallosis) had occurred in around one in five (19%) cases. .
Metal hips implanted into women were also more likely to fail, but the researchers caution that twice as many women as men had bilateral hip replacements, and when the findings were analysed according to sex and liner thickness, thinner liners had the greater impact.
Data from the National Joint Registry for England and Wales for 2014 indicate that 11,871 metal on metal Pinnacle hips have been implanted, prompting the researchers to calculate that 180,000 people around the world are now walking around with these hips. These patients might be at risk of early revision surgery, they suggest.

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MoM Hip Implant Failure Linked to Manufacturing Variation

May 2, 2016 | Medscape

By Diana Phillips

http://www.medscape.com/viewarticle/862707#vp_2
An "unacceptably high" risk for failure and revision surgery associated with a commonly used metal-on-metal hip implant may be partly attributable to the use of components that were outside of stated manufacturing tolerances, investigators report in a study published online April 29 in BMJ Open.
In a first-of-its kind investigation combining clinical data, blood ion concentrations, and explant analysis, David Langton, MBBS, MRCS, from University Hospital of North Tees, Stockton, United Kingdom, and colleagues sought to better understand the performance of metal-on-metal (MoM) hip prostheses by looking specifically at outcomes of patients implanted with the most common of these devices, the Pinnacle MoM 36-mm implant (DePuy).
"There is general acceptance that large diameter [MoM] total hip arthroplasty (THA) has not lived up to clinical expectations," the authors write. "Although the use of MoM hip devices has declined dramatically in the past 5 years, hundreds of thousands remain in situ, with the long-term future uncertain." Gaining insight into the mechanisms that lead to failure can inform management strategies and improve the design of future devices, they note.
For the current study, the investigators reviewed data from a cohort of patients from one hospital trust in northern England who were implanted with the Pinnacle device in conjunction with an SROM modular or Corail femoral uncemented stem between 2003 and 2009. From this subgroup, only those patients whose surgery was performed by the study's two senior authors, both of whom are specialist consultant lower-limb arthroplasty surgeons, were included in the cohort. Patients were identified through National Joint Registry reports, surgical records, and DePuy sales records. Explanted components of failed devices (femoral head, head tapers, and acetabular liners) were evaluated for wear using dimensional and volumetric analysis.
Of 434 identified patients (489 Pinnacle hips), including 243 women and 191 men, in the review, 352 attended recall clinics during which they underwent clinical examination, blood metal ion measurement, X-rays, and more targeted imaging as needed. The mean postsurgery follow-up period for the cohort was 89 months.
Across the full cohort, 71 metal hips required surgical removal and replacement, contributing to an "unacceptably high" revision rate, the authors state.
Although the observed failure rate "does not change the approach to continuing surveillance on patients with MoM total hip arthroscopy, for patients with this implant system, it does provided [an implant] survival rate that can be shared with patients," American Academy of Orthopaedic Surgeons spokesperson David Jevsevar, MD, MBA, said in an interview with Medscape Medical News. Dr Jevsevar, who is chair of the Department of Orthopaedics at the Geisel School of Medicine at Dartmouth University, was not involved in the current study.
Analyses of explanted devices showed that signs of taper-junction failure were more common than signs of bearing failure. Specifically, 50 (70%) of the 71 implant failures showed signs of taper-junction failure, and 34 (48%) of the 71 showed signs of bearing failure.
The results showed higher failure rates in female hips, with a predicted 9-year survival of 77.9% compared with 91.4% for male hips, the authors report. They note, however, that implant survival was significantly lower for patients with bilateral (73.7%) vs unilateral (86.2%) hip implants, and "there were only 31 bilateral male hips compared with 69 bilateral female hips."
Further findings included:
-damage to the abductor musculature in 38 cases
-moderate to severe aseptic lymphocyte-dominated vasculitis-associated lesion observed on retrieved tissue in 36 cases (51%), and
-histologic findings of metallosis with no lymphocytic infiltration in 13 cases (19%).
Manufacturing Variability Increased
In addition, results of explant analyses generated from the pool of Pinnacle MoM devices received at the Northern Retrieval Registry, which is directed by one of the study authors, showed that a significant number of the devices were manufactured with lower diametrical clearances than the manufacturer intended. In that analysis, the authors explain. "The rate of non-conformance appeared to increase over time, with Pinnacles manufactured from the year 2006 onwards significantly more likely to have a clearance value lower than stated to regulators," they write.
Specifically, measurement of the diametrical clearances of all of the head and cup combinations used in the 161 Pinnacle MoM implants received at the Northern Retrieval Registry up until the time of the study showed that 48 devices were below the lower tolerance band, including five that were implanted before 2006 and 43 that were implanted from 2006 and later.
With respect to all-cause revision across the full cohort, the presence of bilateral joints and the late cohort emerged as significant risk factors, and "there was a trend towards increasing risk of revision with smaller liner sizes," the authors report.
Repeating the model with liner sizes as categorical variables found that 50- and 52-mm liner sizes were significant risk factors for early revision. Multiple analyses confirmed the association between smaller liner size and revision risk.
Further, failures related to bearing failure were most common in patients with smaller liners. "Larger liners and earlier date of implantation were associated with a significant reduced risk of revision," according to the authors.
The current study revealed an association between Corail stems with greater blood Co concentrations and grater taper wear rates than SROMs. This association "did not equate to an increase in taper failure identified on explant analysis or revision rate," the authors report. "This result is at odds with DePuy’s own internal studies which found a 5-year revision rate of the Corail Pinnacle of 14.1% vs 4.78% for the SROM Pinnacle MoM systems. We have yet to identify clear evidence of mechanically assisted crevice corrosion — the classical theory of taper failure — and thus do not believe that a CoCr on CoCr head stem combination protects from this mode of failure," the authors stress.
"Other factors appear to be more important than stem type in the success or failure of the device."
One such important factor appears to be the observed manufacturing variation, the authors contend. Lower clearances such as those observed primarily in the post-2006 components "render bearings vulnerable to clamping/lubricant starvation should the cups deflect greater than expected when press fit into the acetabulum."
The investigators also observed substantial variation in the as-manufactured surface of the female taper surfaces, and the surface finish appears to be a "critical factor in material loss at this junction." However, without a large enough sample of sterile implants from pre- and post-2006 manufacture years, they write, "it is currently impossible to know whether variation in taper surface finishes in and of itself explains the difference in failure rates between the patient cohorts pre-2006 and post-2006."
Importantly, the absence of a strong relationship between acetabular cup orientation and blood ion concentrations indicates that failures in this cohort were not the result of inaccurate cup placement.
The results of the study "are not necessarily surprising, but the mechanism of failure in this study is attributed more to taper-neck junction failure [trunnionosis,] rather than bearing surface wear and debris generation," Dr Jevsevar said. "The authors also make a compelling case that failure rates are higher in implants produced after 2006 and suggest that implant production processes changed after that time, leading to the increased failure rate.
Although component positioning has been implicated previously in implant failure, "the authors found that failure was not related to component positioning, and this supports the findings of several other studies," Dr Jevsevar said. "This study demonstrates that MoM failure in this hip system was multifactorial and related to trunnion failure and bearing surface wear."
Further investigation using larger data sets are warranted to confirm the role that variations in manufacturing play in prosthetic failure, according to the authors. The high midterm failure rate of the Pinnacle in this cohort suggests that "tens of thousands of patients around the world are at risk of early revision surgery," they write. "Taper failure appears to be time dependent and a rising Co level should alert the clinician."
The relatively low wear rates of the MoM bearing surfaces in this study, together with the clinical performance of unilateral hips produced before 2006, are "encouraging" observations and suggest that "MoM technology can in certain circumstances be used successfully if taper junctions are suitably optimised," the authors conclude.
Last month, a Texas federal jury ordered Johnson & Johnson and its DePuy unit to pay a total of $500 million in compensatory and punitive damages to five plaintiffs who said they were injured by the Pinnacle metal-on-metal implants.

Dr Langton and three coauthors are retained experts for plaintiffs in ongoing MoM device litigation. Dr Langton and one coauthor have worked with the US Department of Justice in litigation involving DePuy, manufacturer of the prosthesis investigated in this study. Dr Jevsevar has disclosed no relevant financial relationships.

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Regional Outlets

British doctors highlight 'unacceptably high revision rate' for hip implant

Apr 29, 2016 |

By Bailwick Express

http://www.bailiwickexpress.com/jsy/uk/british-doctors-highlight-unacceptably-high-revision-rate-hip-implant/#.VzJE4vkrKUl
British doctors have published evidence of an "unacceptably high revision rate" for a hip implant that has been the subject of a multi-million pound US lawsuit.
Almost 12,000 Britons have received the Pinnacle metal-on-metal hip implant made by DePuy, part of Johnson & Johnson, according to official joint registry data.
Now researchers say they have operated on patients with "black tissue" caused by "high levels of chromium and cobalt" and that patients have suffered pain.
DePuy was forced to recall a different implant (the ASR) in 2010 after the devices were linked to muscle and bone damage and neurological issues.
In March this year, Johnson & Johnson was ordered by a Texas federal jury to pay around 500 million US dollars (£343m) to five people who said they were injured by the Pinnacle metal-on-metal hip implants.
The jury decided the Pinnacle hips were defectively designed and that DePuy had failed to warn the public about their risks.
Johnson & Johnson has said the company will appeal against that verdict. Thousands more people have launched action against the company.
Dr David Langton, from the University Hospital of North Tees, who led the latest study, said his team had told DePuy in the UK, and the Medicines and Healthcare products Regulatory Agency (MHRA), of problems with the Pinnacle over several years.
He said: "These Pinnacle implants were advised for younger patients who were very active.
"We have found that they fail at a higher rate than conventional ones but they fail in a much nastier way.
"You get very high levels of chromium and cobalt around the hip and that can go into the bloodstream. There can be black metal-stained tissue.
"The Pinnacle was put into people in lot bigger numbers than the ASR - up to about 500,000 people worldwide.
"What we've found is that some of our patients have come back with lots of pain. The implants have then been taken out by us.
"In total myself, I've looked at between 150 and 200 Pinnacle implants."
He added: "We've reported this and had several meetings with DePuy and the MHRA.
"We physically handed the implants to DePuy and showed them how they were not the right size and how they were going to fail.
"In my opinion, they should never have left the factory.
"Hips should fail at no more 0.5% per year but we found the Pinnacle has been failing at a significantly higher rate than that."
Dr Langton said his team believed up to 20,000 people in the UK had received the implants.
The study, published in the journal BMJ Open, found in particular that Pinnacle metal on metal implants manufactured and implanted since 2006 were more prone to failure.
The team looked specifically at the long-term performance of the 36mm Pinnacle metal-on-metal hip.
Over the study period, 489 metal-on-metal Pinnacle hips were implanted into 434 patients.
Of these, 352 patients attended future clinics and 71 metal hips required surgical removal and replacement.
There was a revision rate of 16.4%, which researchers described as "unacceptably high".
The study found that before 2006, only five out of 43 hips (12%) failed to meet the manufacturer's product specification.
But after 2006 more than a third (36% or 43 out of 118) failed to comply.
Furthermore, in over 40% of cases, the taper surface - a key part of the implant - was defective.
The authors said this was significantly associated with the excessive release of metal particles.
Staining of bodily tissue had also occurred in around one in five (19%) cases.
In 2012, the MHRA said patients who had undergone large head metal-on-metal hip replacements should be monitored annually for life.
They should have blood tests to check for metal ions, and MRI scans if necessary, it said.
No comment was immediately available from Johnson & Johnson or the MHRA.
An MHRA spokeswoman said: "MHRA take allegations of device non-conformities seriously and will investigate these with manufacturers when sufficient evidence is presented to MHRA.
"We are, however, unable to comment on regulatory matters which may involve a manufacturer due to confidentiality restrictions within the medical device regulations.
"The majority of patients who receive hip implants have well-functioning hips and are at a low risk of developing any serious problems.
"MHRA continues to monitor the performance of all hip implants in the UK though its post market surveillance system.
"We also work closely with our expert orthopaedic advisory group which includes representatives from the British Orthopaedic Association, the British Hip Society and the National Joint Registry for England, Wales, Northern Ireland and Isle of Man to assess any new scientific evidence and we will take safety action if needed to ensure that patients are protected from unsafe hip implants."
Law firm Leigh Day said it was acting on behalf of 333 clients who were claiming compensation from DePuy for having to undergo early revision surgery following a Pinnacle implant.
A three-month trial in the High Court is due to begin in October 2017.
Spokeswoman Sarah Moore said: "We consider that this study is highly significant to the individuals whom we represent.
"The study reports that after analysing hundreds of explanted Pinnacle components, the doctors involved have found that a significant number of devices were found to be manufactured out of their specifications.
"This is a very serious allegation that we will continue to investigate with our expert team.
"If this allegation is proven, this may be a further factor in explaining why so many individuals have suffered severe injuries and early revision following their implantation with these products.

"The evidence of an 'unacceptably high revision rate' should put more pressure on DePuy to come to the negotiating table rather than our clients having to drag them through the courts."

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British doctors highlight ‘unacceptably high revision rate’ for hip implants

Apr 29, 2016 | Evening Express

https://www.eveningexpress.co.uk/pipe/news/uk/british-doctors-highlight-unacceptably-high-revision-rate-for-hip-implant/
British doctors have published evidence of an “unacceptably high revision rate” for a hip implant that has been the subject of a multi-million pound US lawsuit.
Almost 12,000 Britons have received the Pinnacle metal-on-metal hip implant made by DePuy, part of Johnson & Johnson, according to official joint registry data.
Now researchers say they have operated on patients with “black tissue” caused by “high levels of chromium and cobalt” and that patients have suffered pain.
DePuy was forced to recall a different implant (the ASR) in 2010 after the devices were linked to muscle and bone damage and neurological issues.
In March this year, Johnson & Johnson was ordered by a Texas federal jury to pay around 500 million US dollars (£343m) to five people who said they were injured by the Pinnacle metal-on-metal hip implants.
The jury decided the Pinnacle hips were defectively designed and that DePuy had failed to warn the public about their risks.
Johnson & Johnson has said the company will appeal against that verdict. Thousands more people have launched action against the company.
Dr David Langton, from the University Hospital of North Tees, who led the latest study, said his team had told DePuy in the UK, and the Medicines and Healthcare products Regulatory Agency (MHRA), of problems with the Pinnacle over several years.
He said: “These Pinnacle implants were advised for younger patients who were very active.
“We have found that they fail at a higher rate than conventional ones but they fail in a much nastier way.
“You get very high levels of chromium and cobalt around the hip and that can go into the bloodstream. There can be black metal-stained tissue.
“The Pinnacle was put into people in lot bigger numbers than the ASR – up to about 500,000 people worldwide.
“What we’ve found is that some of our patients have come back with lots of pain. The implants have then been taken out by us.
“In total myself, I’ve looked at between 150 and 200 Pinnacle implants.”
He added: “We’ve reported this and had several meetings with DePuy and the MHRA.
“We physically handed the implants to DePuy and showed them how they were not the right size and how they were going to fail.
“In my opinion, they should never have left the factory.
“Hips should fail at no more 0.5% per year but we found the Pinnacle has been failing at a significantly higher rate than that.”
Dr Langton said his team believed up to 20,000 people in the UK had received the implants.
The study, published in the journal BMJ Open, found in particular that Pinnacle metal on metal implants manufactured and implanted since 2006 were more prone to failure.
The team looked specifically at the long-term performance of the 36mm Pinnacle metal-on-metal hip.
Over the study period, 489 metal-on-metal Pinnacle hips were implanted into 434 patients.
Of these, 352 patients attended future clinics and 71 metal hips required surgical removal and replacement.
There was a revision rate of 16.4%, which researchers described as “unacceptably high”.
The study found that before 2006, only five out of 43 hips (12%) failed to meet the manufacturer’s product specification.
But after 2006 more than a third (36% or 43 out of 118) failed to comply.
Furthermore, in over 40% of cases, the taper surface – a key part of the implant – was defective.
The authors said this was significantly associated with the excessive release of metal particles.
Staining of bodily tissue had also occurred in around one in five (19%) cases.
In 2012, the MHRA said patients who had undergone large head metal-on-metal hip replacements should be monitored annually for life.
They should have blood tests to check for metal ions, and MRI scans if necessary, it said.
No comment was immediately available from Johnson & Johnson or the MHRA.
An MHRA spokeswoman said: “MHRA take allegations of device non-conformities seriously and will investigate these with manufacturers when sufficient evidence is presented to MHRA.
“We are, however, unable to comment on regulatory matters which may involve a manufacturer due to confidentiality restrictions within the medical device regulations.
“The majority of patients who receive hip implants have well-functioning hips and are at a low risk of developing any serious problems.
“MHRA continues to monitor the performance of all hip implants in the UK though its post market surveillance system.
“We also work closely with our expert orthopaedic advisory group which includes representatives from the British Orthopaedic Association, the British Hip Society and the National Joint Registry for England, Wales, Northern Ireland and Isle of Man to assess any new scientific evidence and we will take safety action if needed to ensure that patients are protected from unsafe hip implants.”
Law firm Leigh Day said it was acting on behalf of 333 clients who were claiming compensation from DePuy for having to undergo early revision surgery following a Pinnacle implant.
A three-month trial in the High Court is due to begin in October 2017.
Spokeswoman Sarah Moore said: “We consider that this study is highly significant to the individuals whom we represent.
“The study reports that after analysing hundreds of explanted Pinnacle components, the doctors involved have found that a significant number of devices were found to be manufactured out of their specifications.
“This is a very serious allegation that we will continue to investigate with our expert team.
“If this allegation is proven, this may be a further factor in explaining why so many individuals have suffered severe injuries and early revision following their implantation with these products.
“The evidence of an ‘unacceptably high revision rate’ should put more pressure on DePuy to come to the negotiating table rather than our clients having to drag them through the courts.”

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