Comparative study of extended versus short term thromboprophylaxis in patients undergoing elective total hip and knee arthroplasty in Indian population

BACKGROUND: Postoperative thromboprophylaxis with low molecular weight heparin (LMWH) for an extended period of 4 weeks is now preferred over short term thromboprophylaxis in patients undergoing total hip/knee arthroplasty (THA/TKA). However, most of the data demonstrating the efficacy and safety of extended thromboprophylaxis and short term thromboprophylaxis is from clinical trials done in the West. In India, the data of the incidence of venous thromboembolism (VTE) following THA/TKA has been conflicting and the duration has not been clearly defined. The aim of the study was to evaluate and compare the efficacy of extended thromboprophylaxis over short term thromboprophylaxis in Indian patients undergoing elective THA/TKA surgeries. MATERIALS AND METHODS: A prospective arm of 197 consecutive patients undergoing elective THA/TKA surgeries who were administered extended thromboprophylaxis for 4 weeks was compared with a historical group of 795 patients who were administered short term thromboprophylaxis for only 7-11 days. In both groups, LMWH (enoxaparin) was used in a dose of 40 mg subcutaneously, in addition to mechanical thromboprophylaxis. Primary efficacy endpoint was objectively confirmed venous thromboembolism (VTE). The presence of DVT was confirmed by a combination of pretest scoring, D-dimer, and Color Doppler Flow Imaging (CDFI) of deep veins of the legs, and pulmonary thromboembolism (PTE) was confirmed by ventilation perfusion (V/Q) scan or pulmonary angiography. Fisher's exact test and t test were used for the statistical analysis. The baseline confounding factors were compared between the two groups using t test for comparing the means for continuous data and Fisher's exact test for categorical data. RESULTS: In the prospective arm, only 1 patient developed symptomatic PTE compared to 26 (3.27%) cases of VTE (20 cases of PTE and 6 cases of DVT) in the retrospective group. CONCLUSION: Extended thromboprophylaxis (for 4 weeks) was found to be more effective than short term thromboprophylaxis in minimizing the risk of postoperative VTE in patients who underwent THA/TKA.