Wound Problems following Hip Arthroplasty before and after the Introduction of a Direct Thrombin Inhibitor for Thromboprophylaxis

In the United Kingdom, national guidelines have stated that patients undergoing elective hip surgery are at increased risk for venous thromboembolic events (VTE) following surgery and have recommended thromboprophylaxis for 28–35 days (1, 2). Studies of direct thrombin inhibitors have hitherto concentrated on major bleeding. We prospectively assessed wound discharge in patients who underwent hip arthroplasty and who received oral dabigatran postoperatively between March 2010 and April 2010 (n=56). We compared these results to a retrospective matched group of patients who underwent similar operations six months earlier, at which time all patients were given subcutaneous dalteparin routinely postoperatively until discharge, and then discharged home on 150mg aspirin daily for 6 weeks (n=67). Wound discharge after 5 days was significantly higher in the patients taking dabigatran (32% dabigatran n=18, 10% dalteparin n=17, p=0.003) and our rate of delayed discharges due to wound discharge significantly increased from 7% in the dalteparin group (n=5) to 27% for dabigatran (n=15, p=0.004). Patients who received dabigatran were more than five times as likely to return to theatre with a wound complication compared with those who received dalteparin (7% dabigatran n=4, vs. 1% dalteparin n=1), but this was not statistically significant (p=0.18). We now administer dalteparin until the wound is dry and then start dabigatran. Our study demonstrates the need for further clinical studies regarding wound discharge and direct thrombin inhibitors.