Research shows 85% survivorship 5 years after two-stage revisions for infected TKA

Craig J. Della Valle, MD

The authors present extensive experience with a two-stage exchange protocol for treatment of an infected total knee arthroplasty, which includes 253 knees treated over a 17-year time period. The reported survivorship free of infection was 85% at 5 years and 78% at 10 years, although 95% confidence intervals at 10 years were wide given the median follow up of 4 years.

Although no patients were lost to follow-up, the minimum time of follow-up was just 1 year, while most studies that report the outcomes of treatment of infection are at a minimum of 2 years; this is particularly relevant as the median time to failure for recurrent infection was 15 months. It is also interesting to note that many of their patients although clinically infected, were culture negative which the authors hypothesize was secondary to prior antibiotic treatment elsewhere; unfortunately this is an all too common scenario. It is critical for physicians managing patients with a suspected periprosthetic joint infection to obtain deep cultures (via aspiration) prior to the administration of antibiotics to avoid this problem.

This is an important study, given its size, and it suggests that although the results of a two-stage exchange are good, overall survivorship at 10 years free of infection is modest. What remains unclear is how we can improve upon these results. As we have seen in many of our own patients, recurrence of infection is often times with a different organism, suggesting that the patient who becomes infected is for some reason prone to this complication. Whether some modifiable factor that can be treated will be discovered to improve upon these results, or if these patients have some inherent immunodeficiency that dooms them to recurrent failure remains unclear.