Septic arthritis superimposed on an arthritic knee is a surgical dilemma: A 10-year experience with two-stage total knee arthroplasty – the first reported study from South Asia

Abstract Background Septic arthritis superimposed on an osteoarthritic knee is a challenge. Suboptimal outcomes may persist despite successful infection eradication due to preexisting degenerative changes. Evidence supporting two-stage total knee arthroplasty (TKA) for native-knee septic arthritis remains limited. This study reports a 10-year experience with two-stage TKA for acute septic arthritis in osteoarthritic knees. Methods This study retrospectively reviewed prospectively collected data from 26 patients (30 knees) treated with two-stage TKA between January 2015 and January 2025. The first stage comprised extensive synovectomy and debridement, femoral and tibial bone cuts, intramedullary canal reaming, and insertion of a stemmed antibiotic-loaded cement spacer, followed by antibiotic therapy. The second stage was performed after complete resolution of infection. Functional outcomes were evaluated using the Knee Society Score (KSS). Reinfection-, reoperation-, and revision-free survivorship were assessed using Kaplan–Meier analysis. Results The mean age of the cohort was 60.2 ± 10.1 years. Nineteen knees (63.3%) were culture-positive, with Staphylococcus aureus being the most commonly isolated microorganism, while 11 (36.7%) were culture-negative. Articulating spacers were used in 28 knees (93.3%). The mean interval between stages was 10.4 ± 3.1 weeks. Infection was controlled without subsequent surgery for infection in 27 knees (90.0%). Two knees developed superficial surgical-site infection, and one developed early periprosthetic joint infection; all remained infection-free at final follow-up. Mean KSS improved from 45.6 ± 6.8 to 86.6 ± 4.1 (p < 0.001). At a mean follow-up of 38.6 months, revision-free implant survivorship was 96.6%. Conclusion Two-stage TKA provides effective infection control, significant functional improvement, and excellent mid-term implant survivorship in patients with septic arthritis superimposed on an arthritic native knee. These findings support staged TKA as a viable treatment strategy for this challenging clinical scenario.