More than 10,000 patients have been given a faulty knee replacement which doubles the risk of joint failure, The Telegraph can disclose.
The implant, which has been in use since 2003, was withdrawn from the market by its manufacturer in October.
The Telegraph has learnt that UK health regulator the Medicines and Healthcare products Regulatory Agency (MHRA) is now preparing to issue a field safety notice, prohibiting its use.
Available across multiple NHS trusts, the implant, manufactured by Zimmer Biomet, a US firm, has been shown to fail in up to seven per cent of patients after ten years - twice the accepted failure rate of 3.5 per cent set by the National Joint Registry.
One study found the failure rate to be much higher at 17.6 per cent - more than five times as high as the accepted level.
This can have catastrophic consequences for patients, many of whom are elderly, as undergoing a second knee replacement operation poses a much greater risk.
The knee replacement, called the Nexgen, is part of a family of Zimmer Biomet implant devices with 88 possible variants. In total, these have been given to over 183,000 people in England, Wales and Northern Ireland, and more than five million worldwide. Of these variants, three combinations have been proven to place patients at a dangerously high risk of joint failure.
These features are known as: “posterior stabilised” implants, “flex” femoral components, and the standard cemented “option” tibial component.
Of the knee replacements that incorporate these features, two combinations have raised particular cause for concern. They are the LPS Flex Femoral implant with ‘option’ cemented Tibia and the LPS GSF Flex Femoral implant with ‘option’ cemented Tibia.
Together, these two knee replacements have been given to at least 10,420 people in the UK. But around 350 of these patients require a second operation within ten years because the implant has failed, according to figures from the National Joint Registry.
Doctors have warned that this may just be the tip of the iceberg as the registry figures do not account for patients who die before they have a chance to have a second surgery. There are also concerns that many elderly patients with failed knee replacements may have their pain ignored by doctors or have had their surgery dates pushed back due to the NHS backlog due to the Covid pandemic.
Even before the pandemic, research from the charity Versus Arthritis shows that between April 2018 and March 2019, 2,400 NHS patients had to wait more than a year for a hip or knee replacement operation.
Problems occur with the NexGen devices because of “aseptic loosening” of the tibial component. This is the most common cause of implant failure and means the component attached to the shin comes loose, causing pain and inflammation as the implant rubs against the bone. This can be debilitating, leaving people in near constant pain and unable to sleep.
Second knee replacement more risky
Having a secondary knee replacement is much more significant than the initial operation as it requires removing the previous implant and replacing it with a larger device that is surrounded by damaged tissue.
Studies show knee revision operations take twice as long and carry an increased risk of severe bleeding, infection and even death. It also prolongs patient recovery.
In 2021, there were 68,974 primary knee replacements and 5,110 revisions in England, Wales and Northern Ireland, according to the registry. Of these, 1,909 were caused by aseptic loosening.
This is the latest in a series of joint replacement scandals uncovered by this paper. In 2012, The Telegraph disclosed how 30,000 patients were at risk from “metal-on-metal” hip replacements, which caused toxic metal filings to seep into patients’ blood.
Dr Alison Cave, MHRA chief safety officer, said: “We are actively working with relevant stakeholders and reviewing all available evidence from a range of sources on the concerns raised on the performance of the NexGen knee implant. We will take appropriate safety action if necessary.
“If you experience any pain or other problems associated with NexGen knee implants, please speak to your implanting surgeon.”
‘Bad timing for overstretched NHS’
A statement from Zimmer Biomet said: “Zimmer Biomet is committed to patient safety and we take product quality very seriously. We are conducting a voluntary medical device recall related to the NexGen Stemmed Option Tibial Components due to the higher overall revision rates when these tibial components are used with either the LPS Flex or LPS Flex GSF femoral components as compared to other total knee arthroplasties in the United Kingdom National Joint Registry.
“The LPS Flex and LPS Flex GSF femoral components are not being recalled. We are working closely with regulatory authorities on this voluntary recall and information will be sent to surgeons informing them of the details pertaining to this recall next week. At that time, information will also be made available on our website.”
Dr Benjamin Ellis, senior clinical policy advisor to Versus Arthritis and consultant rheumatologist said: “Many people with arthritis will read about these failing implants feeling worried, wondering how an unreliable product was allowed to be given to perhaps 10,000 people who now potentially face the prospect of needing a repeat operation.
“This could not come at a worse time for the overstretched NHS with hundreds of thousands of people already facing unacceptably long waits for joint replacement surgery.”