Abstract
INTRODUCTION: Periprosthetic joint infection (PJI) is a serious complication following total joint arthroplasty. It can be potentially limb- or life-threatening, often necessitating complex surgical intervention and prolonged antimicrobial therapy. While Staphylococcus aureus and coagulase-negative staphylococci are the most commonly implicated pathogens, rare organisms, such as Campylobacter fetus, can occasionally be involved, particularly in immunocompromised patients or those with specific dietary exposures. Due to its low virulence and atypical clinical presentation, infections caused by C. fetus may lead to diagnostic delays. CASE REPORT: We present the case of an 80-year-old woman with a history of total knee arthroplasty, who developed a C. fetus PJI complicated by a draining sinus tract. CONCLUSION: This case underscores the diagnostic complexity of atypical PJI. It highlights the importance of repeated aspirations and comprehensive clinical evaluation. Additionally, it reveals that joint aspiration can yield false-negative results if performed during or shortly after an antibiotic course and contributes to the limited literature on C. fetus as a causative organism in PJI.