Knee Replacements
The question
To ask the Secretary of State for Health and Social Care, what assessment he has made of the potential (a) financial and (b) clinical impact of the Zimmer Biomet NexGen Legacy Posterior Stabilized (LPS) knee replacement system on the NHS.
Answered by Karin Smyth
The Medicines and Healthcare products Regulatory Agency (MHRA) issued a field safety notice (FSN) in December 2022 about some devices in the NexGen family of knee implants. The FSN was issued following notification by the National Joint Registry (NJR) Implant Scrutiny Committee in 2021.
The NexGen Stemmed Option Tibial Component was removed from the market because of that notice, although only use in combination with LPS Flex or LPS Flex GSF femoral components demonstrated higher revision rates, and only patients receiving the combination of devices were recommended to be reviewed.
As is standard with joint replacement FSNs, the NJR supplied hospitals with a list of all the patients who had this combination implant and were still alive and had not already had a revision procedure. This represented 9,125 cases from 102 hospitals. This all happened within 48 hours of the FSN being issued. For context, 11,965 of these were implanted if patients who had died or been revised were included.
In terms of the clinical impact, the NJR had first been asked to investigate use of high flex NexGen knees by a surgeon in 2014. Although the data did not meet the outlier threshold at that time, NJR did inform the MHRA because there appeared to be a particular mechanism of failure with these devices, namely tibial loosening. The MHRA followed its standard process of discussing the concerns with the manufacturer and the matter was closed since the data did not demonstrate a case to answer. NJR reported this again in 2021, by which time the data was more robust and the signal was stronger.
At the time for an implant to be rated 10A, which is a measure of implant success, according to the National Institute for Health and Care Excellence (NICE), a failure rate of 10% at 10 years was used. This has recently been changed to a failure rate of 5% at 10 years.
The failure rate of this implant combination at 10 years is 7%, which is still under the 10% threshold advocated by NICE. It is important that these patients remain under clinical and radiological review.
NJR has made no assessment of the financial impact of the NexGen family of knee implants.
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