Why Are Total Knee Arthroplasties Failing Today: What Has Changed After Two Decades?

BACKGROUND

There were two previous studies at our institution that evaluated the reasons behind total knee arthroplasty (TKA) failure, the first from 1997 to 2000 and the second from 2003 to 2012. The purpose of this study was to evaluate the frequency and causes for TKA failure over the past decade and provide an updated comparison with our previous findings.

METHODS

We retrospectively reviewed 4,084 revision TKA patients from 2012 to 2023. Indication for revision and re-revisions were recorded. Time to failure from primary TKA was classified as early (less than two years) or late (greater than two years). We compared indications for revision to prior series published at our institution in 2002 and 2012. A multivariate analysis was performed to identify risk factors for undergoing a subsequent surgery.

RESULTS

When compared to patients from the 2002 and 2012 series, common causes of failure in 2024 included aseptic loosening (24.1 versus 39.9 versus 35.2%), instability (21.2 versus 7.5 versus 22.8%), infection (17.5 versus 27.4 versus 20.1%), and polyethylene wear (25.0 versus 3.5 versus 3.3%, P < 0.01). The percentage of early revisions declined (55.6 versus 37.6 versus 30.0%, P < 0.01). The prevalent causes of early failure included infection (30.6%), instability (24.0%), and loosening (20.5%), while late failures were caused by loosening (42.1%), instability (22.5%), and infection (15.4%) (both [P < 0.0])). Patients being revised for loosening (odds ratio 0.41, P < 0.01) and instability (odds ratio 0.34, P < 0.01) had a lower likelihood of undergoing a reoperation.

CONCLUSION

In our 10-year update, the percentage of revisions done for instability increased since 2012, comparable to 2002 levels, while polyethylene wear continues to decrease as a cause of TKA failure. Early failures have decreased in the past two decades, suggesting improved surgical techniques. Infection and loosening remain unsolved problems.