Tag Archives: lancet medical journal

Knee implants: more evidence needed? – Behind The Headlines – Inverurie Herald

The effectiveness of knee replacement surgery was in the news today, when the BBC and Independent reported that more evidence was needed on the long-term safety of knee implants.

The news, which follows recent reports on the safety of PIP breast implants and certain metal hip implants, is based on a report on knee replacement surgery published in The Lancet medical journal. it argued that although knee replacement surgery is highly successful as a treatment for osteoarthritis, there is a need for more long-term monitoring of surgery outcomes and steps to ensure that patients selected for surgery are suitable.

In addition, the report’s authors say that new implant designs are continually being introduced, often with little or no evidence of their effectiveness, and that more long-term monitoring of their safety and effectiveness is needed.

Although some online news sources have suggested that the review article found knee replacement to be dangerous, this is misleading. The report says that knee replacement is generally successful but that more needs to be done to assess which patients will benefit, to collect data on outcomes and to carefully monitor the introduction of new implant designs.

Knee replacements are usually carried out when the knee has been damaged by arthritis. in most cases, surgery is for osteoarthritis, the most common form of this disease, although it is also used for other forms. in osteoarthritis, the parts of the knee that slide over each other as you move become damaged, through either gradual wear or an injury. Only a small number of people with arthritis in the knees are given knee replacement surgery. it is usually considered if someone is in persistent, disabling pain and if non-surgical treatments, such as physiotherapy, have not helped.

During the operation, the surfaces of the knee joint that have been damaged by arthritis are removed and replaced by new parts, made of metal and plastic. in effect, this artificial hinge replicates the natural range of movements of the knee. Patients can have either a total knee replacement (TKR), in which all the surfaces are replaced, or a partial knee replacement, in which only part of the knee is replaced. a TKR is the most common form of the operation.

Knee replacement surgery is an increasingly common procedure and the number of operations is rising annually. over 70,000 knee replacement operations are carried out each year, about four out of five of them in women. in the UK, rates of knee replacement operations in women increased from 43 per 100,000 person years in 1991 to 137 per 100,000 person years in 2006.

The average age for having this surgery is 70 years old but, according to the new report, knee replacement is increasingly being considered for patients younger than 55. The authors say that the reason for this trend is unclear. For example, it could be due to increased patient expectation or more osteoarthritis among young people because of the increasing incidence of obesity.

Knee replacement surgery is generally considered to be a highly successful operation. it improves pain, mobility and quality of life in many people with advanced arthritis of the knee joint. The charity Arthritis Research says that about four out of five people who’ve had the operation say they are happy with their new knees. however, some people are disappointed with the outcome of their surgery or are unsure whether there has been an improvement.

This is why it’s important to ensure that patients considered for the operation are those who would derive the most benefit. The National Institute for Health and Clinical Excellence (NICE) says that although joint replacement operations can provide very good pain relief for many people with osteoarthritis, in a substantial number of cases the outcome is not good enough. “It would be very useful to have pre-operative tools to help choose the people who would derive most benefit,” NICE commented.

The new review article argues that there’s an urgent need for improved decision making to assess whether a patient should undergo the procedure. Evidence-based information should be given to patients about factors that are known to influence the outcome of their surgery.

The article also says that long-term monitoring of outcomes is needed, through national joint-replacement registries and electronic patient records reporting the rates of revision surgery and other outcomes.

All major operations carry some immediate risks, including blood clots and infection. in the longer term, knee replacement surgery can lead to complications. These include the knee giving way (instability) or continuing to hurt, numbness around the joint, problems with bending and the need for a second operation to correct or remove part of the implant, known as revision surgery. The need for revision surgery is often the result of the new joint becoming loose. Other common reasons include infection, pain and stiffness.

Some internet news reports implied that the review has judged knee replacements to be unsafe. however, the article primarily discussed the decision-making processes behind knee replacement surgery and the need to gather evidence on the best practice for knee replacement and on the effectiveness of new implant designs. it did not suggest that knee replacement is unsafe or that it should be stopped, although it did argue for improved collection of safety data.

The report says that orthopaedic manufacturers are continually introducing new designs for implants and that doctors expect that these new implants will improve outcomes. however, there is evidence to suggest “this belief is incorrect”.  The new implants are often introduced with little or no evidence of their effectiveness, the report adds.

Limited release of new implant designs as part of well-conducted large-scale randomised controlled trials is essential, the authors argue. in addition, national joint registries should monitor the outcomes of new implant designs.

The report says that national joint replacement registries, such as the UK’s National Joint Registry (NJR), are one of the best and most important sources of data on knee replacement surgery. These registries collect data on measures such as revision surgery, as well as patient-reported outcomes.

According to the report, improved long-term monitoring of outcomes using both national registries and electronic patient records should be undertaken. This is so that both patients and surgeons have good-quality evidence to assess different implants and techniques and to improve decision making.

The Medicines and Healthcare products Regulatory Agency has reportedly said that since April 2003, all knee joint replacement operations in England and Wales have been recorded by the NJR.

If your implant is causing problems or you are anxious about it, ask your GP to refer you to your surgeon.

Knee implants: more evidence needed? – Behind The Headlines – Inverurie Herald

Knee implants: more evidence needed?

Published on Monday 18 June 2012 21:40

The effectiveness of knee replacement surgery was in the news today, when the BBC and Independent reported that more evidence was needed on the long-term safety of knee implants.

The news, which follows recent reports on the safety of PIP breast implants and certain metal hip implants, is based on a report on knee replacement surgery published in the Lancet medical journal. it argued that although knee replacement surgery is highly successful as a treatment for osteoarthritis, there is a need for more long-term monitoring of surgery outcomes and steps to ensure that patients selected for surgery are suitable.

In addition, the report’s authors say that new implant designs are continually being introduced, often with little or no evidence of their effectiveness, and that more long-term monitoring of their safety and effectiveness is needed.

Although some online news sources have suggested that the review article found knee replacement to be dangerous, this is misleading. the report says that knee replacement is generally successful but that more needs to be done to assess which patients will benefit, to collect data on outcomes and to carefully monitor the introduction of new implant designs.

Knee replacements are usually carried out when the knee has been damaged by arthritis. in most cases, surgery is for osteoarthritis, the most common form of this disease, although it is also used for other forms. in osteoarthritis, the parts of the knee that slide over each other as you move become damaged, through either gradual wear or an injury. only a small number of people with arthritis in the knees are given knee replacement surgery. it is usually considered if someone is in persistent, disabling pain and if non-surgical treatments, such as physiotherapy, have not helped.

During the operation, the surfaces of the knee joint that have been damaged by arthritis are removed and replaced by new parts, made of metal and plastic. in effect, this artificial hinge replicates the natural range of movements of the knee. Patients can have either a total knee replacement (TKR), in which all the surfaces are replaced, or a partial knee replacement, in which only part of the knee is replaced. A TKR is the most common form of the operation.

Knee replacement surgery is an increasingly common procedure and the number of operations is rising annually. Over 70,000 knee replacement operations are carried out each year, about four out of five of them in women. in the UK, rates of knee replacement operations in women increased from 43 per 100,000 person years in 1991 to 137 per 100,000 person years in 2006.

The average age for having this surgery is 70 years old but, according to the new report, knee replacement is increasingly being considered for patients younger than 55. the authors say that the reason for this trend is unclear. For example, it could be due to increased patient expectation or more osteoarthritis among young people because of the increasing incidence of obesity.

Knee replacement surgery is generally considered to be a highly successful operation. it improves pain, mobility and quality of life in many people with advanced arthritis of the knee joint. the charity Arthritis Research says that about four out of five people who’ve had the operation say they are happy with their new knees. However, some people are disappointed with the outcome of their surgery or are unsure whether there has been an improvement.

This is why it’s important to ensure that patients considered for the operation are those who would derive the most benefit. the National Institute for Health and Clinical Excellence (NICE) says that although joint replacement operations can provide very good pain relief for many people with osteoarthritis, in a substantial number of cases the outcome is not good enough. “It would be very useful to have pre-operative tools to help choose the people who would derive most benefit,” NICE commented.

The new review article argues that there’s an urgent need for improved decision making to assess whether a patient should undergo the procedure. Evidence-based information should be given to patients about factors that are known to influence the outcome of their surgery.

The article also says that long-term monitoring of outcomes is needed, through national joint-replacement registries and electronic patient records reporting the rates of revision surgery and other outcomes.

All major operations carry some immediate risks, including blood clots and infection. in the longer term, knee replacement surgery can lead to complications. These include the knee giving way (instability) or continuing to hurt, numbness around the joint, problems with bending and the need for a second operation to correct or remove part of the implant, known as revision surgery. the need for revision surgery is often the result of the new joint becoming loose. Other common reasons include infection, pain and stiffness.

Some internet news reports implied that the review has judged knee replacements to be unsafe. However, the article primarily discussed the decision-making processes behind knee replacement surgery and the need to gather evidence on the best practice for knee replacement and on the effectiveness of new implant designs. it did not suggest that knee replacement is unsafe or that it should be stopped, although it did argue for improved collection of safety data.

The report says that orthopaedic manufacturers are continually introducing new designs for implants and that doctors expect that these new implants will improve outcomes. However, there is evidence to suggest “this belief is incorrect”.  the new implants are often introduced with little or no evidence of their effectiveness, the report adds.

Limited release of new implant designs as part of well-conducted large-scale randomised controlled trials is essential, the authors argue. in addition, national joint registries should monitor the outcomes of new implant designs.

The report says that national joint replacement registries, such as the UK’s National Joint Registry (NJR), are one of the best and most important sources of data on knee replacement surgery. These registries collect data on measures such as revision surgery, as well as patient-reported outcomes.

According to the report, improved long-term monitoring of outcomes using both national registries and electronic patient records should be undertaken. this is so that both patients and surgeons have good-quality evidence to assess different implants and techniques and to improve decision making.

The Medicines and Healthcare products Regulatory Agency has reportedly said that since April 2003, all knee joint replacement operations in England and Wales have been recorded by the NJR.

If your implant is causing problems or you are anxious about it, ask your GP to refer you to your surgeon.

Knee implants: more evidence needed?

UK Study Prompts Call for Wider Ban on Metal Hips

New research confirmed that all-metal artificial hips fail more often than other types, fueling concerns about the devices and prompting a call from researchers this week for a ban.

The analysis in The Lancet medical journal came two weeks after Britain’s medical regulator said nearly 50,000 Britons with metal-on-metal hips needed annual check-ups to monitor for problems, including exposure to toxic metals.

The finding will likely fuel criticism about the regulation of medical devices in the wake of a scandal over French-made breast implants and past problems with other implantable devices, including faulty leads on some heart defibrillators.

Metal-on-metal hips were developed to be more durable than traditional implants, which combine a ceramic or metal ball with a plastic socket.

But recent experience suggests they may actually do worse, prompting the recall of one device made by Johnson & Johnson that critics argue should never have been allowed on the market.

Results from the most comprehensive study to date now show that there is a 6.2 percent chance patients with all-metal hips will need a replacement within five years – some three times greater than the revision rate seen with older implants.

The rate was particularly high with larger-head implants and those used in women, in whom failure rates were up to four times higher, the researchers said.

The team from the University of Bristol analysed data from the National Joint Registry of England and Wales covering more than 400,000 hips replacements, including 31,171 all-metal ones, that were undertaken between 2003 and 2011.

The results, they said, were unequivocal: “Metal-on-metal stemmed articulations give poor implant survival compared with other options and should not be implanted.”

Their analysis did not cover resurfacing systems, which avoid the use of a stem sticking into the bone, such as Smith & Nephew’s Birmingham Hip Resurfacing joints.

TIGHTER REGULATION

In recent years, the use of metal-on-metal implants has declined in Britain, but they are still used extensively around the world, including in the United States.

Art Sedrakyan of Cornell University said the problem highlighted weaknesses in the regulatory systems on both sides of the Atlantic due to “outdated and low-threshold regulatory pathways.”

In a strongly worded Lancet commentary accompanying the latest research, he called for better studies before implants reach the market.

“we are left with more than 500,000 patients with metal-on-metal prostheses in the USA and more than 40,000 in the UK who are at elevated risk of device failure, which will inevitably result in the burden of further surgical treatment as well as billions of dollars in costs to taxpayers,” he said.

Ashley Blom of the University of Bristol said that total hip replacement surgery remained a very successful operation for the vast majority of people but regulators should learn lessons as they seek to balance safety against innovation.

“in this case, with the benefit of hindsight, I think that tighter regulation may have prevented this,” he told Reuters.

Under the new guidelines from Britain’s Medicines and Healthcare Products Regulatory Agency (MHRA), doctors are being advised to consider removing and replacing implants if patients have abnormal MRI scans or if metal ion levels in the blood reach worrying levels.

With the exception of J&J’s DePuy ASR system, which was pulled from the market in 2010, the MHRA decided in its recent ruling against a ban on use, arguing that stemmed metal-on-metal implants could still be good news for some patients.

Other companies that make metal-on-metal hip implants include Zimmer, Stryker, Corin and Biomet.

UK Study Prompts Call for Wider Ban on Metal Hips

Ban metal-on-metal hip replacements, experts urge

Experts are calling for controversial metal-on-metal hip implants to be banned after they found “unequivocal evidence” of high failure rates.

Data on more than 400,000 hip replacements found metal-on-metal implants needed revising more often than other types and that failure rates were higher in women.

It comes two weeks after the Medicines and Healthcare products Regulatory Agency (MHRA) issued new guidance on the implants, saying almost 50,000 patients in the UK will need annual blood or MRI checks.

Tiny metal ions made up of cobalt and chromium are thought to break off from the implants and leak into the blood, with fears this causes muscle and bone damage as well as neurological issues.

The MHRA says there is a “small risk” the implants can cause complications in patients.

The research, published in the Lancet medical journal and based on the National Joint Registry of England and Wales, found metal-on-metal implants failed much more quickly than other types of implant, with a five-year revision rate of 6.2%.

This compared with 2.3% for ceramic-on-ceramic implants and 1.7% for metal-on-plastic types.

Failure was related to the head size of the implant, with larger heads failing more quickly. this was equivalent to a 2% increase in the risk of failure for each 1mm increase in head size. by contrast, ceramic-on-ceramic types of implants performed better with larger head sizes.

The analysis included more than 31,000 metal-on-metal implants. it looked at patients given implants between 2003 and 2011 and tracked for up to seven years after surgery.

The results showed stark differences between the implants depending on type and head size, and confirm previous findings on failure rates.

In women, failure rates for metal-on-metal were up to four times higher than for other types, and were also higher compared with men even with the same head size.

At seven years after surgery, some revision rates were as high as 10%, such as for 55-year-old women with a 46mm head implant. For women with a 36mm head, the revision rate was 8.4%.

At five years after surgery, revision rates were 6.1% for women with a 46mm diameter metal-on-metal implant, compared with just 1.6% for those with a 28mm metal-on-plastic implant.

In men aged 60 with metal-on-metal implants, revision rates were 3.2% for a 28mm head, jumping to 5.1% for a larger 52mm head.

The experts concluded: “Metal-on-metal stemmed articulations give poor implant survival compared with other options and should not be implanted.

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

The authors said they agreed with MHRA advice but surgeons should seek to use other implants.

Alison Smith, a statistician in orthopaedic surgery at the University of Bristol, added: “We think there are better alternatives so we don’t see a reason to use stemmed metal-on-metal implants any longer.”

Around 65,000 people in the UK have received metal-on-metal hip implants since 2003, of which 49,000 are affected by the MHRA’s guidance because the joint head is 36mm or greater.

Hip replacements are mostly used for patients with osteoarthritis, where there is substantial wear and tear on the hip joint.

The use of metal-on-metal implants has declined in England and Wales, but data suggests they are still used extensively in the US.

Ban metal-on-metal hip replacements, experts urge