Venous thromboembolism, including deep vein thrombosis (DVT), has long been recognized as the most frequent complication within 7 to 14 days after orthopedic surgery, especially total joint arthroplasty. Without prophylactic therapy, the incidence of DVT and pulmonary embolism reaches up to 60% following orthopedic surgery. The possible damage to the vessel wall during the operation, the venous stasis caused by long-term bed rest, and the hypercoagulability of the blood after the surgery are the 3 main reasons for the formation of DVT. In most cases, the thrombi resolve spontaneously; however, some of them (about 1~4%) may develop into symptomatic and even fatal DVT.

Ankle pumping exercise is currently suggested for the patients with joint placement surgery to prevent the formation of lower-extremity DVT after orthopedic surgery. However, the compliance of the exercise at home is unclear. In order to remind the patients to the active ankle exercise and record the executive rate, a device was developed to help the patient to exercise in the hospital and at home. The device will remind the patient to exercise at specific time point by verbal and vibrations, and detect the range of motion during the exercise for further analysis. The aim of this study is to access the effect of a non-invasive novel device in preventing the formation of lower limb DVT. Maximum venous outflow, maximum venous capacity, and blood rheology were measured and the incidence of DVT was recorded for the data analysis.

Background. Deep vein thrombosis (DVT) has long been recognized as the most frequent complication that occurs 7-14 days after total knee replacement (TKR). Physical therapy, including active ankle pumping exercises and intermittent pneumatic compression, is suggested for the prevention of DVT. However, the exercise implementation rate is not clear, particularly at home. In order to remind the patients to exercise after TKR, a watch with voice and vibration alarms at the set time was used.

Objective The first aim of this study was to compare the effect of active ankle movement with and without reminders on the prevention of DVT. The second aim was to compare the difference in the effect of intermittent pneumatic compression and active ankle movement on the prevention of DVT.

Design. A Pilot Randomized Controlled Trial Methods. The patients were divided into three groups according to the therapeutic protocols. The patients in group 1 conducted active ankle pumping without any reminders, those in group 2 underwent intermittent pneumatic compression, and those in group 3 conducted active ankle pumping with a regular watch alarm. The parameters of blood flow, namely peak flow velocity and flow volume, in the bilateral common femoral vein and popliteal vein on the 1st, 3rd, and 14th days after surgery were measured using the echo technique, as an index to evaluate the effect of DVT prevention among the three groups.

Inclusion Criteria:

• patients who underwent total knee replacement surgery

Exclusion Criteria:

• Patients with a history of cardiovascular disease, such as DVT, dyslipidemia, hypertension, myocardial infarction, and hemorrhagic disease were excluded from this study.