The NexGen Knee: A ticking timebomb

Jack Pearce

University Hospital Southampton

Zimmer’s NexGen Knee was introduced in 1995 and further updated with ‘High Flex’ devices.
Initially noted in UHS in 2015, there appeared to be a significant proportion undergoing early failure.
Recently noticed exponential increase in failing NexGen’s with a common pattern: atraumatic aseptic medial tibial collapse. At time of revision surgery tibial base plate found to have completely de-bonded from cement.
We have undertaken a retrospective review of our primary total knee revisions since December 2019 to evaluate what percentage of our workload this has become and how early the implants are failing.

Inclusion criteria: all elective first revisions of primary total knee replacements since 01/12/2019
The departments local revision knee database was used to identify all procedures since December 2019.
With each identified case their preoperative clinic notes, imaging, bloods, microbiology and operation notes (primary and revision) were accessed to confirm they met inclusion criteria

125 revision knee procedures of which 55 were first revisions of primary total knee replacements.
30 of 55 (55%) were NexGen knees with 22 having failed in the common pattern.
The average time from primary operation to listing for revision was only 63 months

With >3000 replacements having been put in at Southampton and failure between 21 and 206 months in this cohort there is a potential exponential increase in revisions coming.
We feel group wide follow up should be initiated and any patients reporting pain should have a work-up including a SPECT CT.