Objective To investigate the risk factors for acute calf muscular venous thrombosis(CMVT)in elderly patients with hip fractures and evaluate the diagnostic value of thrombotic risk index for CMVT.Methods The blood samples from elderly emergency admission patients with traumatic hip fractures were prospectively collected,and platelet count(PLT),plateletcrit(PCT),coagula-tion markers such as thrombin-activatable fibrinolysis inhibitor(TAFI),D-dimer,and fibrinogen(Fib),and biochemical markers,including serum total protein(TP),globulin(Glob),creatine kinase(CK),triglyceride(TG),and lactate dehydrogenase(LDH),were detected.The differences in these markers between the CMVT group,deep calf venous thrombosis(DCVT)group and non-deep venous thrombosis(DVT)group were compared.The multivariate logistic regression analysis was used to identify independent risk fac-tors for CMVT,and a thrombotic risk index was generated to evaluate its diagnostic value in CMVT.Results Compared with the non-DVT group,the levels of TAFI,Fib,TP,CK,TG,PCT,and LDH in the CMVT group were significantly reduced(P<0.05),while the level of D-dimer increased but the difference was not statistically significant.The level of TP in the DCVT group was significantly lower than that in the non-DVT group(P<0.05).Multivariate analysis showed that age,LDH,and Fib were independent risk factors for CMVT.The area under the receiver operating characteristics(ROC)curve of the thrombotic risk index in diagnosing CMVT was 0.718(P<0.001).Conclusion Age,LDH,and Fib are the independent risk factors of CMVT in elderly patients with hip fractures.The thrombotic risk index has a high diagnostic value in CMVT.