BackgroundRetention of a prosthesis represents an attractive surgical modality for the infected but well-fixed knee prosthesis because patients need to stay in bed after removal of all components. Some additional postoperative treatment would be needed, however, when treated only with débridement because of its low success rate. MethodsIn this study, intraarticular antibiotic infusion into the infected joints after débridement, while retaining the implants, was performed for six well-fixed total knee arthroplasties (TKAs), one revision TKA, and five tumor megaprostheses with an average follow-up period of 47.5 months (range 20–82 months). TKA patients with a polyethylene insert or those with all exchangeable components and all polyethylene parts in tumor megaprostheses underwent device removal and thorough débridement of the soft tissues. Subsequently, new polyethylene inserts were implanted in the TKA patients. The removed metallic prostheses were resterilized and reimplanted, and new polyethylene inserts were implanted in the tumor megaprostheses patients. The wound was closed in layers after insertion of a catheter percutaneously. The patients received organism-specific intraarticular antibiotics through the catheter twice a day until the infection disappeared clinically. ResultsThere was no recurrence of infection in the TKA and revision TKA patients. Four of five knees treated with tumor megaprostheses exhibited recurrence of the infection. Infection was finally healed, however, in all cases by the same treatment procedure. ConclusionsAlthough some patients experienced recurrence of infection, successful implant salvage was achieved in all cases with the same treatment procedure. Patients do not need to stay in bed during this treatment. Therefore, this method should be considered as one of the treatment options for infected knee prostheses.