The optimal strategy for postoperative deep venous thrombosis prophylaxis remains controversial in hip and knee arthroplasty. Warfarin causes transient hypercoagulability; however, the optimal timing of treatment remains unclear. We evaluated the effects of preoperative versus postoperative warfarin therapy with a primary endpoint of perioperative change in hemoglobin. Warfarin was dosed according to a standard nomogram. No difference in perioperative hemoglobin change was observed. The preoperative group demonstrated higher INRs. Initiation of warfarin preoperatively was not associated with any difference in perioperative hemoglobin change. Larger studies are needed to determine whether the risk of adverse events is increased with either strategy.
We were unable to detect any difference in complication rates between groups.
We were unable to detect any difference in complication rates between groups.
After receiving appropriate Institutional Review Board approval, the electronic medical records for patients in the study population were retrospectively reviewed for INR levels (on POD 1 and 2), drain outputs (on POD 1, when all drains were removed), and change between preoperative and postoperative hemoglobin levels (on PODs 1 and 2). Patients were monitored clinically, but no Doppler studies or other screening modalities were performed to detect asymptomatic DVTs. The number of adverse events related to anticoagulation (wound healing complications, hematomas [abnormal swelling and fluid accumulation within the knee], epidural complications, and transfusions) or thrombosis (symptomatic DVT, pulmonary embolus) was also noted. These outcomes were compared between patient populations using a χ 2 test for categorical variables (wound healing complications, hematomas, and transfusions) and the Student t test for continuous variables (postoperative INR, drain output, and change between preoperative and postoperative hemoglobin levels). Adverse events (transfusions, hematomas, epidural complications, symptomatic DVT, and pulmonary embolus) were compared using the 2-tailed Fischer’s exact test.
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