Background Two-stage exchange arthroplasty is a standard approach for treating total knee arthroplasty periprosthetic joint infection in the United States, but whether this should be performed with a static antibiotic spacer or an articulating one that allows range of motion before reimplantation remains controversial. It is unclear if the advantages of articulating spacers (easier surgical exposure during reimplantation and improved postoperative flexion) outweigh the disadvantages of increased cost and complexity in the setting of similar rates of infection eradication. Questions/purposes The purposes of this study were (1) to determine the ultimate range of motion; and (2) to determine the proportion of patients who remained free of infection at a minimum 2 years after treatment with static antibiotic spacers as part of a two-stage revision TKA for the treatment of periprosthetic joint infection. Methods Between 1999 and 2011, we treated 121 patients with chronically infected TKAs, of whom three had medical comorbidities precluding a two-stage exchange, four had died before 2-year followup for reasons other than the surgical intervention, and seven were lost to followup. The remaining 107 patients (109 knees; 53 men and 54 women) were treated using a two-stage approach with static spacers and are evaluated here at a mean of 3.7 years (range, 2.0-9.8 years); no patients were treated with articulating spacers during this study period. Twenty-five percent (27 of 109) of the organisms isolated the first-stage procedure were resistant to methicillin and/or vancomycin. Median age at the time of reimplantation was 67 years (range, 42-89 years). Range of motion was measured by an independent physical therapist with a standard goniometer. Knee Society knee and function scores were calculated before the first stage and at the 2-year mark. Because many of these patients were treated before consensus definitions Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research 1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. This work was performed at Stanford University Medical Center, Stanford, CA, USA. of infection were established, we made ...