Abstract: Objective  To investigate the significance of color Doppler ultrasound in lower extremity deep vein before release from hospital.
  Methods  A retrospective analysis was conducted on 26 patients with deep vein thrombosis(DVT) after orthopaedic surgery in Xiangjiang district of the Third Hospital of Hebei Medical University. By analyzing their gender, age, disease diagnosis in department of orthopedics, complications of underlying diseases, types of thrombosis, location and complications of pulmonary embolism, the proportion of different diseases and the distribution of thrombus types were compared.
  Results  In 26 patients with lower limb DVT, three cases of central thrombosis was accounting for 11.54% of the 26 patients(3 cases of superficial femoral vein thrombosis), while 22 cases of peripheral thrombus were accounting for 84.62% of the 26 patients(3 cases of popliteal vein thrombosis , 3 cases of posterior tibial vein thrombosis, 5 cases of fibula thrombosis, 11 cases of intermuscular venous thrombosis).There were 1 cases of thrombus, accounting for 3.85%. There were no significant differences among the three thrombus types in gender, age, obesity, hypertension, diabetes mellitus, surgical method, blood transfusion history, and fracture type composition ratio(P＞0.05). There were 4 cases of multiple fractures( accounting for 15.38%), 9 cases of hip joint replacement and hip fracture(accounting for 34.62%), 6 cases of knee joint surface replacement and knee fracture(accounting for 23.08%),2 cases of ankle joint fracture and foot fracture(accounting for 7.69%), 5 cases of lower limb tubular bone fracture(accounting for 19.23%). During the course of anticoagulation and thrombolytic therapy, all patients had no major bleeding and pulmonary embolism and other related complications.
  Conclusion  Color Doppler ultrasound examination has the advantages of safety,simplicity,convenience,real-time dynamics,repeatabilityand non-invasiveness. It can be used as the preferred method of routine DVT examination. It can detect thrombus in time before discharge and take effective intervention measures to reduce discharge It is worthy of clinical promotion to avoid serious complications such as pulmonary embolism, improve the prognosis of patients and improve the quality of life.

Key words: fracture, deep vein thrombosis, Color doppler flow imaging