The incidence of trauma patients requiring surgery and prolonged immobilisation is rising, mainly because of the increasing popularity of recreational sports. However, the epidemiology and prevention of VTE after such injuries have been poorly studied. The combination of limb surgery with or without trauma in orthopaedic surgery is responsible for an increase in venous thromboembolism (VTE). Usually, surgery of lower limb is considered as moderate or high risk for DVT with different duration related to immobilisation. For instance tibia osteotomy is at very high risk during at least 6 weeks and knee arthroscopy for ligament repair is at moderate risk during 10 days. However LMWH is recommended in both surgeries. Non-major orthopaedic surgery represents a major additional risk factor by itself; therefore such patients undergoing surgery deserve to receive VTE prophylaxis.