Toward Evidence-Informed Staging in Septic Revision Total Knee Arthroplasty: One-Stage, 1.5-Stage, or Two-Stage?

Periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) remains one of the most consequential complications in adult reconstruction because successful treatment requires simultaneous infection control, restoration of a mechanically durable knee, preservation of function, and minimization of surgical morbidity. Two-stage exchange has traditionally been regarded as the reference strategy for chronic knee PJI, but contemporary comparative evidence increasingly challenges its routine use as the default for all patients. This narrative review synthesizes evidence from systematic reviews, meta-analyses, comparative cohorts, propensity-matched analyses, and decision-analytic studies evaluating one-stage, 1.5-stage, and two-stage septic revision TKA. The available data indicate that infection control after one-stage revision is broadly comparable with, and in some analyses superior to, two-stage revision in carefully selected patients. Conversely, two-stage exchange retains a central role in patients with severe host compromise, complex bone or soft-tissue defects, multidrug-resistant or fungal infection, uncertain microbiology, and reconstructive instability. The 1.5-stage strategy has emerged as a pragmatic function-preserving alternative, with encouraging infection-free survivorship and lower treatment burden; however, its long-term mechanical durability remains incompletely defined, particularly because aseptic loosening is consistently identified as a key risk. Evidence-based staging should therefore move beyond a binary hierarchy and toward an algorithm integrating host status, organism profile, soft-tissue envelope, bone loss, fixation requirements, prior failure, timing, and patient goals. Current evidence supports individualized multidisciplinary decision-making rather than routine use of any single staging strategy, while highlighting the need for prospective knee-specific studies using standardized definitions, patient-reported outcomes, mechanical survivorship, and cost-effectiveness endpoints.