Authors (including presenting author) :
Lo CK(1), Lee QJ(1), Wong YC(1)
Affiliation :
(1) Yan Chai Hospital Joint Replacement Centre
Introduction :
Deep vein thrombosis is a significant complication in patients receiving total knee replacement. There is currently no standardized thromboprophylaxis protocol in Hong Kong for total knee replacement surgery. Before January 2014, all patients scheduled for total knee replacement in our Centre, who (1) had a body mass index of more than 30kg/m2, (2) had history of venous thromboembolism or malignancy, (3) were put on oral contraceptive medication and (4) were Caucasian, would receive enoxaparin 40mg subcutaneous injection daily for 7 days after operation as thromboprophylaxis. Following a publication from our Centre, which found a low incidence of venous deep vein thrombosis after total knee replacement surgery in obese patient, we set up a new thromboprophylaxis protocol such that only group 2, 3 and 4 patients requires enoxaparin injection.
Objectives :
The aim of the study is to assess the clinical efficacy and safety of our new thromboprophylaxis protocol for obese patients in total knee replacement surgery
Methodology :
This is a retrospective study reviewing all patients received primary total knee replacement from October 2011 to May 2019 in our Centre. Patients with a body mass index over 30 kg/m2 were included for analysis. Patients who had history of venous thromboembolism or malignancy, took oral contraceptive pills and Caucasian patients were excluded. All patients received a routine duplex ultrasound of their lower limbs at day 4 to 7 after operation. The diagnosis of deep vein thrombosis was defined as superficial or common femoral veins not being fully compressible, presence of hyper-echoic signal within the veins and absence of venous flow.
Result & Outcome :
A total of 772 patients were included in our analysis. 4 out of 555 patients (0.7%) underwent operation according to the new thromboprophylaxis protocol developed deep vein thrombosis compared to 2 out of 217 patients (0.9%) operated before January 2014. There was no statistical difference in the deep vein thrombosis rate among the two groups (p=0.979). This is the largest local study on thromboprophylaxis protocol for total knee replacement surgery. The deep vein thrombosis rate of our patient was comparable to international studies. Our study concluded that the use of enoxaparin cannot lower the incidence of deep vein thrombosis after total knee replacement in obese patients. Our protocol is effective in preventing deep vein thrombosis after total knee replacement surgery while reducing the cost and complications associated with the use of enoxaparin.
