Risk-Stratified Venous Thromboembolism Chemoprophylaxis After Total Joint Arthroplasty: Evaluation of an Institutional Approach.

: The optimal venous thromboembolism (VTE) chemoprophylaxis approach after hip or knee total joint arthroplasty (TJA) remains controversial. This study aimed to characterize antithrombotic-related complications associated with various chemoprophylaxis regimens after TJA and to assess our current institutional risk-stratified prescribing tool. : This retrospective case-control study and regression analysis included elective unilateral TJA patients at a single institution between 1 July 2015 and 31 December 2021. The primary outcome was a composite of antithrombotic-related complications within 30 days of surgery, including thrombotic and hemorrhagic/wound-related adverse events. The duration of anticoagulant chemoprophylaxis prescribed prior to aspirin monotherapy (0-28 days) was compared between patients who did vs. did not experience a complication, with stratification by institutionally defined VTE risk categories (Routine, Moderate, or High Risk). The complication rate was then assessed as a function of anticoagulant duration within each risk subgroup. : The study included 5420 patients, with 279 (5.2%) experiencing ≥1 complication. Routine VTE risk patients experienced few complications, with no significant difference between aspirin monotherapy and various initial anticoagulant durations ( = 0.6118). Moderate and High VTE Risk patients saw significantly lower complication rates with initial anticoagulant prophylaxis of increasing durations ( = 0.0090 and = 0.0050), with a significant overall effect of VTE Risk strata observed ( = 0.0006). : When both bleeding and thrombotic events are considered, anticoagulant-to-aspirin regimens were associated with lower complication rates than aspirin monotherapy in higher risk patients, while routine patients saw no significant benefit over aspirin. Our risk-stratified prescribing approach should be prospectively evaluated.