This study is researching an experimental drug called REGN7508 (called study drug). The study is focused on adults undergoing elective, unilateral (one side) total knee replacement surgery. The aim of the study is to see how effective the study drug is at preventing venous thromboembolism (VTE) and other related diseases after total knee replacement surgery. The study is looking at several other research questions, including: * What side effects may happen from taking the study drug * How much study drug is in the blood at different times * Whether the body makes antibodies against the study drug (which could make the study drug less effective or could lead to side effects)