Abstract:[Objective] To explore the anatomical distribution of deep vein thrombosis (DVT) in the low extremity and factors related to the proximal DVT after primary total knee arthroplasty (TKA) . [Methods] A retrospective study was performed on 824 patients who under- went primary total knee arthroplasty in our hospital from January 2016 to December 2018. The anatomic characteristics of the DVT were an- alyzed, while the related factors of lower extremity deep vein thrombosis were analyzed by univariate comparison and multivariate logistic regression. [Results] Of the 824 patients, 97 patients (11.77%) (97/824) were diagnosed of DVT by postoperative ultrasonography. One case (0.12%) (1/824) was diagnosed as pulmonary embolism by CTPA. After operation, there were 40 cases (41.24%) (40/97) of symptomatic thromboses, and 57 cases (58.76%, 57/97) of asymptomatic thromboses. According to whether the DVT involved the popliteal vein or not it was divided into two categories. Of them, 15 patients suffered from proximal DVT, accounting for 15.46% (15/97) , whereas the remaining 82 patients were of distal DVT, accounting for 84.54% (82/97) . In term of detection time point, 60 patients had DVT detected 1 day after operation, accounting for 61.86% (60/97) , while 37 patients had DVT found newly 3 days after operation, accounting for 38.14% (37/97) . As results of univariate comparison, the proximal DVT group had significantly longer operation time and anesthesia time than the distal DVT group (P<0.05) , and the former had significantly higher ratio of preoperative varicosity than the latter (P<0.05) . However, there were no significant differences in terms of general documents, preoperative blood tests, and other information related to operation between the two groups (P>0.05) . As consequences of multivariate logic analysis, the longer operative time (OR=1.111, 95%CI: 1.011~1.220, P=0.028) was an independent risk factor for proximal DVT after total knee arthroplasty. [Conclusion] The distal DVT is the most common type of them after total knee arthroplasty. However, longer operative time is a risk factor for proximal DVT.