Reinfection and re-revision rates of periprosthetic knee infection under four different surgical strategies: a single centre retrospective observational study

Background Management strategies for (suspected) periprosthetic joint infection after total knee arthroplasty (TKA-PJI) include debridement, antibiotics, and implant retention (DAIR); one-stage revision; 1.5-stage revision; and two-stage revision. Reported outcomes for these four approaches vary widely across studies, with failure rates ranging from 0% to 40%. This study aims to compare the four strategies in terms of reinfection rates, microbial profiles of recurrent infections, short- and long-term infection-free prosthesis survival, re-revision rates for any cause, and long-term implant loosening-free survival. Methods We conducted a retrospective cohort analysis of 145 patients who underwent DAIR, one-stage revision, 1.5-stage revision, or two-stage revision for TKA-PJI at our centre between October 2012 and October 2022. All patients had a minimum follow-up of 2 years. Diagnosis of PJI was based on the Musculoskeletal Infection Society (MSIS) criteria for PJI. Results After a median follow-up of 99 (35, 164)months, infection recurred in 25 cases (18.8%). Of these, 7 cases (5.3%) were defined as relapses (same organism as the initial revision), 14 cases (10.5%) as new infections (different organism), and 4 cases (3.0%) had indeterminate infection type. In 5 patients DAIR successfully eradicated the reinfection. After overall follow-up 25 patients (18.8%) underwent re-revision surgery, 17 patients (12.8%) due to an infection and 8 patients (6.0%) for aseptic reasons. The cumulative reinfection rates at 2 years after DAIR, one-stage revision,1.5-stage revision, and two-stage revision was 14.6% (95% CI: 7.8% to 15.1%), 16.0% (95% CI: 9.7% to 21.2%), 13.8% (95% CI: 8.4% to 18.9%), and 4.0% (95% CI: 3.0% to 11.1%), respectively; at 5 years was 18.4% (95% CI: 9.2% to 16.4%), 20.8% (95% CI: 11.6% to 22.2%), 17.9% (95% CI: 10.0% to 19.8%), and 17.0% (95% CI: 8.1% to 14.1%), respectively. Overall, the cumulative reinfection rates at 2 and 5 years was 11.0% vs. 18.2% (χ2 = 2.950, P = 0.093). The prosthesis-free infection survival rates at 2 and 5 years after DAIR, one-stage revision,1.5-stage revision, and two-stage revision were 85.4% vs. 81.6%, 84.0% vs. 79.2%, 86.2% vs. 82.1%, and 96.0% vs. 83.0%, respectively. Conclusion Treatment of a (suspected) TKA-PJI by four strategies—DAIR, one-stage, 1.5-stage, and two-stage revision—had acceptable results based on re-revision and reinfection rates in the long-term (>5 years), resembling the short-term results (<2 years). Focussing on the cultures at the time of initial revision, the incidence of new infections during follow-up was twice that of relapses. Reinfection rates were higher in cases with positive cultures at reimplantation. Patients should be counselled appropriately in this particular situation.