The invention relates to the use of semuloparin or a pharmaceutically acceptable salt thereof for the prevention of a mortality and/or morbidity event, more specifically venous thromboembolism and death, in a patient undergoing major orthopaedic surgery, such as hip replacement, knee replacement or hip fracture surgery.本發明係關於瑟莫羅培林(semuloparin)或其醫藥上可接受之鹽之用途,其用於在接受重大骨科手術(例如髖置換手術、膝置換手術或髖骨折手術)之患者中預防死亡及/或發病事件、更特定而言靜脈血栓栓塞及死亡。