Two-Stage Modular Intramedullary Knee Arthrodesis for Persistent Periprosthetic Joint Infection After Failed Total Knee Arthroplasty: Mid-Term to Long-Term Outcomes.

Background: Persistent periprosthetic joint infection (PJI) after failed total knee arthroplasty (TKA) remains a challenging condition, particularly in patients with severe bone loss or compromised soft tissues. Modular intramedullary knee arthrodesis is a limb-salvage option; however, evidence on mid-term to long-term outcomes remains limited. This study evaluated infection control, functional outcomes, and complications following 2-stage modular intramedullary knee arthrodesis. Methods: A retrospective analysis of 30 patients who underwent 2-stage modular intramedullary knee arthrodesis for persistent PJI after failed TKA was performed, with a mean follow-up of 7.2 ± 1.8 years. Outcomes included infection recurrence, functional scores (Oxford Knee Score [OKS], Visual Analog Scale [VAS], and Functional Independence Measure [FIM]), time to weight bearing, and mechanical complications. Results: Among the 30 patients available for final analysis, no clinical or laboratory evidence of recurrent infection, or infection-related reoperation, was observed during follow-up. Functional outcomes improved significantly (p < 0.05), with mean OKS increasing from 14.3 ± 2.6 to 43.5 ± 1.3, mean VAS decreasing from 8.4 ± 1.2 to 1.1 ± 0.5, and FIM scores improved from 70.5 ± 3.12 to 121.3 ± 2.3. Early mobilization was achieved, with progression to full-weight bearing at a mean of 22 days. No mechanical or implant-related complications were observed. Conclusion: Two-stage modular intramedullary knee arthrodesis provides durable infection control, early mobilization, and improved functional outcomes at mid-term to long-term follow-up in patients with persistent PJI after failed TKA. Level of Evidence: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.