Pre-randomization treatment with LMWH anticoagulant is allowed for a maximum duration of 24 hours. However, only a single pre-randomization dose of LMWH is allowed. After randomization, patients allocated to the rivaroxaban arm will receive rivaroxaban 10 mg once-daily started 6-10 hours provided haemostasis has been established after surgery or 24h hours after LMWH injection if needed for the intended treatment duration of 2 to 12 weeks based on medical judgment (according to immobilization). Patients allocated to the comparator arm will receive enoxaparin once daily for the same intended treatment duration. All patients will have a 30-day observational period after cessation of treatment.