The aim of this systematic review was to investigate the outcomes of knee arthrodesis (KA) after periprosthetic joint infection (PJI) of the knee. Differences in clinical outcomes and complication rates among the intramedullary nailing (IMN), external fixation (EF), and compression plating (CP) procedures were compared. A total of 23 studies were included. Demographics, microbiological data, types of implants, surgical techniques with complications, reoperations, fusion, and amputation rates were reported. A total of 787 patients were evaluated, of whom 601 (76.4%), 166 (21%), and 19 (2.4%) underwent IMN, EF, and CP, respectively. The most common causative pathogen was coagulase-negative Staphylococcus (CNS). Fusion occurred in 71.9%, 78.8%, and 92.3% of the patients after IMN, EF, and CP, respectively, and no statistically significant difference was found. Reinfection rates were 14.6%, 15.1%, and 10.5% after IMN, EF, and CP, respectively, and no statistically significant difference was found. Conversion to amputation occurred in 4.3%, 5%, and 15.8% of patients after IMN, EF, and CP, respectively; there was a higher rate after CP than after EF. The IMN technique is the most common option used for managing PJI with KA. No differences in terms of fusion, reinfection, or conversion-to-amputation rates were reported between IMN and EF. CP is rarely used, and the high amputation rate represents an important limitation of this technique.