2026 Southeastern Residency Conference

Title: Evaluation of Thromboprophylaxis Strategies for Orthopedic Surgery Patients

Background: Orthopedic surgery patients are high-risk for post-operative venous thromboembolism (VTE) and often require prolonged prophylaxis. Several studies demonstrated that aspirin (ASA) is non-inferior to traditional prophylactic regimens, such as enoxaparin (LMWH), in orthopedic surgery, however these studies are limited regarding therapeutic durations, transitions of care, and inpatient versus outpatient practices. This has led to significant heterogeneity in practice regarding VTE prophylactic agents. This study aims to compare local rates of post-operative VTE and bleeding for patients receiving ASA vs LMWH prophylaxis.

Methods: This retrospective, observational cohort study included adults with surgical femur fractures or femur fractures with prosthetic replacement at Prisma Health Midlands sites between May 2024 and May 2025 receiving either ASA or LMWH for inpatient post-operative VTE prophylaxis. Therapeutic anticoagulation and those with contraindications to either therapy were excluded. The primary outcome was a composite of VTE events or bleeding during post-operative admission. Secondary outcomes included outpatient VTE or bleeding within 60 days, and evaluation of factors that may affect choice of agent. Tertiary outcomes evaluated therapeutic durations, duplications, and transition opportunities.

Results: Rates of the primary outcome of VTE and bleeding during post-operative admissions were not significantly different between groups (adjusted OR 1.05, 95% CI 0.39-2.28), nor were rates of VTE and bleeding from discharge to 60 days post-op (adjusted OR 0.78, 95% CI 0.26-2.40). Provider factors had the largest influence on choice of agent. Half of patients who received LMWH inpatient were switched to ASA on discharge and only 62% of patients had an appropriate stop date on their prophylactic agent.

Conclusion: No significant differences in VTE and bleeding were found between ASA and LMWH groups, both inpatient and post-discharge. Opportunities for improvement exist for several aspects of prophylactic therapy related to transitions of care.