The presentation of Lyme arthritis can mimic periprosthetic joint infection (PJI) caused by typical bacterial organisms. A patient with left total knee arthroplasty (TKA) and chronic Lyme disease presented to our institution with Lyme-associated PJI. He complained of pain, erythema, and fever for 3 days and met Musculoskeletal Infection Society criteria for PJI. Preoperative synovial fluid Lyme polymerase chain reaction (PCR) and serological tests were positive, whereas both preoperative aspiration and intraoperative cultures were negative. The patient underwent resection arthroplasty with insertion of an antibiotic spacer followed by intravenous ceftriaxone and oral doxycycline treatment for 6 weeks. He underwent reimplantation at 8 weeks after repeat synovial fluid PCR analysis was negative. At 1 year, the patient was asymptomatic with a painless, functional, revision TKA. It is essential to consider Lyme-associated PJI in the setting of culture-negative PJI, especially in regions with a high prevalence of Lyme disease.