PRONOMOS is an international multicentre, interventional, parallel, randomised, double-blind non-inferiority study comparing rivaroxaban 10mg od to an active comparator, enoxaparin 4000 UI od in 4040 valid subjects requiring orthopaedic surgery (except low risk such material removal foot surgery or hallux valgus without patient risk factor [6], and major orthopaedic surgeries for femoral neck and trochanteric fractures, THR, TKR)