The invention relates to the use of semuloparin or a pharmaceutically acceptable salt thereof as an antithrombotic treatment in patients undergoing major orthopaedic surgery, wherein said use involves an improved benefit-risk profile, compared to a standard antithrombotic treatment.本發明係關於一種瑟莫羅培林(semuloparin)或其醫藥可接受鹽作為接受重大骨科手術之病患抗血栓治療之用途,其中該用途相較於標準抗血栓治療具有增進之效益-風險概況。