Comparative Study Of Prophylaxis Of Venous Thromboembolism After Total Hip Replacement Following Femoral Neck Fracture

Purpose:To compare the efficacy and bleeding risk of long term use of direct inhibitor of FXa (rivaroxaban, began with rivaroxaban lOmg orally12h postoperatively, once a day for35days) and short term use of low molecular weight heparin (LMWH)(enoxaparin, begins with enoxaparin4000u by subcutaneous injection12h postoperatively, once a day for14days) in the prophylaxis of venous thromboembolism after total hip replacement following femoral neck fractures by observing the clinical effect and adverse events in the process of treatment.Methods:105patients corresponding to the inclusion criterion and suffering from femoral neck fractures followed by total hip replacement were randomized into one of the two groups by drawing by the computer:①53cases in the rivaroxaban group:began with rivaroxaban lOmg orally12h postoperatively, once a day for35days;②enoxaparin group: began with enoxaparin4000u by subcutaneous injection12h postoperatively, once a day for14days. Patients were monitored for clinical symptoms and signs associated with VTE postoperatively. Once there was presentation related to VTE, Color Doppler and CTA were performed on time. Color Doppler was performed to confirm whether there was DVT in either lower extremity3-5days postoperatively before ambulation and35±4days postoperatively, respectively. The conditions of DVT were recorded and the incidences of DVT were calculated for both groups. The values of D-dimer on the2nd and10th postoperative day were recorded to to evaluate the efficacy of both therapy programs. Bleeding events were recorded for both groups during the treatment period; extra blood transfusion rate which was defined as the incidence of blood transfusion except for routine transfusion of1.5u concentrated red blood cell and150ml plasma was recorded; bleeding events in the first35days postoperatively were calculated to evaluate the safety of both therapy programs. There were no significant differences with regard to general data between patients of both groups, including gender, age, height, duration from injury to operation, et al (P>0.05). All the procedures were performed by one senior surgeon to maximize the comparability regarding surgical procedures with nearly the same preoperative preparation and postoperative medication for patients of both groups.Results:9cases of DVT occurred in the105patients postoperatively (8.5%), in which4were all asymptomatic DVT in the rivaroxaban group (7.5%);5were in the LMWH group (9.6%), with4asymptomatic DVT and1femoral vein thrombosis which presented as swelling and swelling pain in the lower extremity and was detected by Color Doppler. There was no significant difference with regard to the incidence of DVT between the2groups (χ2=0.143, P=0.71). Extra blood transfusion was needed in15cases of rivaroxaban group, with extra blood transfusion rate being28.3%, compared with13cases and25%of enoxaparin group, with no significant differences (P>0.05). Ecchymosis around the wound occurred in7cases of rivaroxaban group, and5cases of LMWH group, repectively, which all disappeared in35±4days postoperatively. Melena occurred with OB(+) in1case of rivaroxaban group, which improved with OB(-) after discontinuation of anticoagulant and beginning of medication of gastrointestinal mucosa protection. Gingival bleeding occurred in1case of LMWH group, which improved after discontinuation of medication.Conclusion:Compared with short term use of low molecular weight heparin (enoxaparin, begins with enoxaparin4000u by subcutaneous injection12h postoperatively, once a day for14days), long term use of direct inhibitor of FXa (rivaroxaban, begins with rivaroxaban10mg orally12h postoperatively, once a day for35days) was effective in the prophylaxis of VTE after total hip replacement following femoral neck fractures in the old with the same good efficacy and without increasing bleeding risk.