Abstract: Objective To investigate the predictive value of mean platelet volume/lymphocyte ratio (MPVLR) and soluble thrombolodulin (sTM) in postoperative deep vein thrombosis (DVT) of lower extremity in patients with lower extremity fracture. 
Methods A total of 89 patients with lower extremity fracture admitted to the hospital were selected. All patients received surgical treatment and were divided into the occurrence group and non-occurrence group according to whether the patients developed DVT of lower extremity after surgery. The incidence of DVT of lower extremity in patients with lower extremity fracture after surgery was analyzed, the levels of peripheral blood MPVLR and sTM in the occurrence and non-occurrence groups were compared, and the clinical data of the occurrence and non-occurrence groups were compared. The influencing factors of DVT of lower extremity in patients with lower extremity fracture after surgery were analyzed by multivariate Logistic regression, and receiver operating characteristic (ROC) curve was drawn. Area under the ROC curve (AUC) was used to analyze the predictive value of preoperative peripheral blood MPVLR and sTM levels alone and in combination for postoperative DVT of lower extremity in patients with lower extremity fracture. 
Results Postoperative DVT occurred in 21 of 89 patients with lower extremity fracture, with an incidence of 23.60% (21/89), and no DVT occurred in the remaining 68 patients. The levels of MPVLR and sTM in peripheral blood of the occurrence group were higher than those of the non-occurrence group, suggesting significant differences (P＜0.05). There were significant differences between the two groups in age ≥60 years, duration of operation ≥2 h, postoperative use of anticoagulant drugs, body mass index (BMI) and duration of postoperative bed rest (P＜0.05). Logistic regression analysis showed that age ≥60 years, duration of operation ≥2 h, increased BMI, MPVLR level and sTM level in peripheral blood were influencing factors for postoperative DVT of lower extremity in patients with lower extremity fracture (P＜0.05). ROC curve results showed that the AUC values of preoperative peripheral blood MPVLR and sTM levels alone and in combination for prediction of postoperative DVT in patients with lower extremity fracture were 0.716, 0.705 and 0.861, respectively (P＜0.05), and the AUC value of the combined prediction of the two indexes was higher than that predicted by the single index (P＜0.05). 
Conclusion Preoperative detection of peripheral blood MPVLR and sTM can be used to predict the occurrence of DVT of lower extremity in patients with lower extremity fracture, and the combination of the two has higher predictive value. 

Key words: fractures, mean platelet volume, lymphocytes, venous thrombosis