To summarize the risk factors of deep venous thrombosis (DVT) in elderly patients with femoral neck fracture after total hip replacement (THA).

To analyses of patients with THA in Wenchang People′s Hospital of Hainan Province from July 2017 to may 2019. Inclusion criteria: age≥60 years old, fragility fracture, unilateral femoral neck fracture, ability of cooperation for functional exercises, and the follow-up time was no less than six months. Exclusion criteria: use of anticoagulant drugs within one week before operation, previous postoperative infection, severe dysfunctions of heart, liver or kidney, and malignant tumor, coagulation dysfunction, rheumatoid disease, myocardial infarction and other similar diseases, previous history of thrombosis and disseminated intravascular coagulation, mental disorder, etc. The patients were divided into the thrombus group and the non-thrombus group according to whether DVT occurred within 30 d after THA. Age, gender, interval between operation and injury, body mass index (BMI), anesthesia method, intraoperative blood loss, activated partial thromboplastin time(APTT), plasma prothrombin time(PT), plasma fibrinogen(FG), and plasma D-dimer(DD) were analyzed in the two groups. Multivariate logistic regression was used to analyze the related factors of venous thrombosis in lower limbs.

According to the inclusion and exclusion criteria, a total of 69 patients were included in the study, including 14 patients in the thrombus group and 55 patients in the non thrombus group. There was no statistically significant difference in age (t=-1.439), gender (P=0.496), interval time between operation and injury (P=0.698), BMI (Z=-1.806), coagulation index (APTT: Z=-1.728, PT: t=-1.594, FG: Z=-1.081, DD: Z=-1.806) between the two groups (all P>0.05). There was no significant difference in anesthesia method (P=0.278), intraoperative blood loss (Z=-0.481), APTT(Z=-1.179) and PT (Z=-1.129) change two days after operation either. The changes of FG (Z=- 5.663) and DD (Z=- 5.745) in the thrombus group were significantly higher than those in the non thrombus group, and also the operation time (Z=- 4.377) was longer than that in the non thrombus group (P<0.05). Logistic regression analysis showed that prolonged operation time, increased FG level, increased DD level two days after operation were independent risk factors for DVT after THA of femoral neck fracture (OR=4.137, 10.105, 16.794, P < 0.05).

The increased time consuming of THA, high level of FG and DD after THA may be associated with DVT, which should be paid attention to. Targeted treatment can be taken to reduce the incidence of DVT and improve the prognosis of patients.