The Effect of Warfarin Use on Postoperative Outcomes after Femoral Neck Surgery

Introduction: Anticoagulation use in the elderly is common for patients undergoing femoral neck hip surgery. However, its use presents a challenge to balance it with associated comorbidities and benefits for the patients. As such, we attempted to compare the risk factors, perioperative outcomes, and postoperative outcomes of patients who used warfarin preoperatively and patients who used therapeutic enoxaparin. Methods: From 2003 through 2014, we queried our database to determine the cohorts of patients who used warfarin preoperatively and the patients who used therapeutic enoxaparin. Risk factors included age, gender, Body Mass Index (BMI) > 30, Atrial Fibrillation (AF), Chronic Heart Failure (CHF), and Chronic Renal Failure (CRF). Postoperative outcomes were also collected at each of the patients' follow-up visits, including number of hospitalization days, delays to theatre, and mortality rate. Results: The minimum follow-up was 24 months and the average follow-up was 39 months (range: 24-60 months). In the warfarin cohort, there were 140 patients and 2055 patients in the therapeutic enoxaparin cohort. Number of hospitalization days (8.7 vs. 9.8, p = 0.02), mortality rate (58.7% vs. 71.4%, p = 0.003), and delays to theatre (1.70 vs. 2.86, p < 0.0001) were significantly longer for the anticoagulant cohort than the therapeutic enoxaparin cohort. Warfarin use best predicted number of hospitalization days (p = 0.00) and delays to theatre (p = 0.01), while CHF was the best predictor of mortality rate (p = 0.00). Postoperative complications, such as Pulmonary Embolism (PE) (p = 0.90), Deep Vein Thrombosis (DVT) (p = 0.31), and Cerebrovascular Accidents (CVA) (p = 0.72), pain levels (p = 0.95), full weight-bearing status (p = 0.08), and rehabilitation use (p = 0.34) were similar between the cohorts. Conclusion: Warfarin use is associated with increased number of hospitalization days and delays to theatre, but does not affect the postoperative outcome, including DVT, CVA, and pain levels compared to therapeutic enoxaparin use. Warfarin use proved to be the best predictor of hospitalization days and delays to theatre while CHF predicted mortality rate.