1. In this randomized controlled trial, the combination of vancomycin with cefazolin was not superior to surgical antimicrobial prophylaxis with cefazolin alone in patients undergoing arthroplasty. 2. Prophylaxis with vancomycin and cefazolin was associated with an increased risk of hypersensitivity reactions and decreased risk of acute kidney injury (AKI) compared to cefazolin alone. Evidence Rating