Poster 222: Venous Thromboembolism Risk factors and Prophylaxis Patterns in Knee Arthroscopy: A Large Database Study

OBJECTIVES: Incidence of venous thromboembolism (VTE) after knee arthroscopy is reportedly low, but rates vary significantly across literature. Current guidelines recommend against routine perioperative thromboprophylaxis, but prescribing practices and VTE risk factors are poorly understood. METHODS: Medical records for patients ≥18 years of age were queried from the Pearl Diver database using CPT codes for arthroscopic knee procedures. Patients with a previous diagnosis of VTE or hyper-coagulable disorder were excluded from analyses. Procedures were grouped by rehabilitation protocols, with restrictive procedures requiring a period of non-weightbearing or postoperative immobilization. Patients who received perioperative thromboprophylaxis were identified. Patients diagnosed with VTE, including pulmonary embolism and/or deep vein thrombosis, within 90 days of surgery were identified using International Classification of Diseases (ICD) codes. Multivariable logistic regression models were utilized to identify VTE risk factors and likelihood of thromboprophylaxis prescription. Covariates included age, restrictive rehabilitation protocols, oral contraceptive pill (OCP) use, and medical comorbidities. RESULTS: A total of 718,289 patients underwent knee arthroscopy from 2011 to 2020. 10,769 patients (1.5%) received perioperative thromboprophylaxis, including aspirin (n=5,353, 0.7%), low molecular weight heparin (n=4,563, 0.6%) and factor Xa inhibitors (n=947, 0.1%). A total of 7,618 patients (1.1%) experienced VTE. Perioperative prophylaxis was associated with decreased odds of experiencing VTE (adjusted odds ratio [aOR] = 0.64, 95% confidence interval [CI] = 0.51 to 0.79) (Table 1). Restrictive procedure type was associated with increased odds of experiencing VTE (aOR =1.42, 95% CI = 1.34 to 1.50) and receiving prophylaxis (aOR=1.95, 95% CI = 1.87 to 2.05). OCP use (aOR = 1.63, 95% CI = 1.37 to 1.91), renal disease (aOR = 1.33, 95% CI = 1.18 to 1.50) and congestive heart failure (aOR = 1.30, 95% CI = 1.13 to 1.49) were associated with increased odds of VTE. Tobacco use was associated with increased odds of VTE (aOR = 1.12, 95% CI 1.03 to 1.22), but decreased odds of receiving perioperative prophylaxis (aOR = 0.84, 95% CI 0.78 to 0.91). Malignancy was associated with increased odds of receiving prophylaxis (aOR = 1.18, 95% CI 1.09 to 1.29) but not with increased odds of VTE. CONCLUSIONS: Procedures with restrictive rehabilitation protocols, OCP use, renal disease, and congestive heart failure are associated with increased odds of VTE following knee arthroscopy. Conversely, the use of perioperative thromboprophylaxis is associated with significantly lower odds of VTE. Risk factors for postoperative VTE are not always correlated with increased likelihood of receiving perioperative thromboprophylaxis. Patients with a tobacco use history may be an at-risk population that can be better selected for thromboprophylaxis when clinically appropriate.