OBJECTIVES: To estimate re-hospitalization and bleeding rates during the 90 days after a venous thromboembolism (VTE) event in patients who underwent knee replacement surgery and to compare the outcomes with patients who did not suffer VTE. METHODS: Based on 2005-2007 national Medicare claims, all patients who underwent knee replacement surgery were identified. The 90 days follow-up event rates for patients who had a VTE event during their initial hospitalization were calculated. Events were compared between patients who suffered a VTE event and those who did not. Risk adjustment was done using propensity score matching (using the ProbChoiceTM algorithm) controlling for baseline demographic and clinical characteristics between patients with and without VTE. RESULTS: In patients who underwent total knee replacement surgery (n=104,952), 1.9% had post-operative VTE events during their initial hospitalization.  Almost 69% (n=1377) of these patients had deep vein thrombosis (DVT), 25% (n=501) had pulmonary embolism (PE), and 6% (n=119) had both DVT and PE.  The overall likelihood of mortality was four times higher for VTE patients versus those without VTE (1.35% vs. 0.35%). Patients with VTE during their initial hospitalization were more likely to be hospitalized in 90 days (compared to patients without an event during the same hospital stay (16.62% vs. 8.00%).  In 90 days after the event, patients with VTE were more likely to have bleeding (10.17% vs. 2.68%). CONCLUSIONS: VTE events during initial hospitalization for total knee replacement surgery increased the adverse events compared with no VTE events.