INTRODUCTION: As advances in efficacy of human immunodeficiency virus (HIV) and hepatitis-C virus (HCV) anti-viral medications increase, patients are able to maintain higher quality of lives than ever before. While these patients live longer lives, the unique patient population of those co-infected with both HIV and HCV increases. As these older patients seek orthopaedic care, it is important to understand their unique outcome profile. The purpose of this study was to evaluate the complication rate after total joint arthroplasty (TJA) in patients with HIV and HCV coinfection compared with patients with HIV or HCV only. METHODS: A retrospective review of patients undergoing primary total joint arthroplasty (TJA) at our urban, academic hospital between April 2016 and April 2019 was conducted. Patients were stratified into three groups according to viral status: HIV only, HCV only, or HIV and HCV coinfection. Baseline demographics, intravenous drug (IV) use, surgery type, CD4+ count, follow-up and complications were analysed. RESULTS: Of the 133 patients included in the study, 28 had HIV, 88 had HCV and 17 were coinfected with both HIV and HCV. Coinfected patients were more likely to have a lower BMI (p < 0.039) and a history of IV drug use (p < 0.018) compared to patients with either HIV or HCV only. Coinfected patients had a higher complication rate (41%) than both HIV only (7%; p < 0.001) and HCV only (12.5%; p < 0.001) patients. DISCUSSION: Patients coinfected with HIV and HCV undergoing TJA have a higher complication rate than patients with either infection alone. As this unique population of coinfected patients continues to expand, increasingly they will be under the care of arthroplasty surgeons. Improved awareness and understanding of the baseline demographic differences between these patients is paramount. Recognition of the increased complication rates grants the opportunity to improve their orthopaedic care through preoperative and multidisciplinary management.