Efficacy and safety of rivaroxaban thromboprophylaxis after arthroplasty of the hip or knee: retrospective cohort study.

Introduction Venous thromboembolism (VTE) is a potentially fatal complication of hip arthroplasty and knee arthroplasty. The National Institute for Health and Care Excellence recommend rivaroxaban for VTE prevention. Amid concerns over bleeding complications, the modified thromboprophylaxis policy of Chelsea and Westminster Hospital (CWH; London, UK) advises enoxaparin given after surgery in the inpatient setting followed by rivaroxaban upon hospital discharge. This retrospective study investigated the efficacy and safety of rivaroxaban in this novel, modified venous-prophylaxis regimen in a surgical orthopaedic cohort at CWH. Methods A total of 479 patients who received modified thromboprophylaxis treatment at CWH after hip arthroplasty or knee arthroplasty between April 2013 and October 2014 formed the study cohort. Seven outcomes based on efficacy and safety while undergoing treatment with rivaroxaban were investigated: symptomatic deep-vein thrombosis (DVT), pulmonary embolism (PE), death, stroke, myocardial infarction (MI), major bleeding episodes (MBEs) and non-major bleeding episodes (NMBEs). Median follow-up was 369 days. Fisher's exact and Mann-Whitney U-tests were adopted to identify associations with these outcomes. Results Prevalence of symptomatic PE, DVT, death, stroke and MI during treatment was zero. One (0.2%) MBE and nine (1.9%) NMBEs occurred. The MBE (a wound haematoma) required a return to theatre for aspiration. Off-treatment VTEs occurred in four (0.8%) patients after completion of a course of rivaroxaban, and were associated with known risk factors. Conclusions Rivaroxaban is an effective and safe anticoagulant for thromboprophylaxis after hip arthroplasty or knee arthroplasty if used in a modified regimen involving enoxaparin administered in the inpatient setting followed by rivaroxaban upon hospital discharge.