High Altitude as a Risk Factor for Venous Thromboembolism in Tibial Plateau Fractures

Background: Tibial plateau fractures are often significant injuries that can require complex surgical interventions with prolonged perioperative immobilization, thereby increasing the risk of developing venous thromboembolic (VTE) events, specifically, deep vein thrombosis (DVT) and pulmonary embolism (PE). Risk stratification is paramount for guiding VTE prophylaxis. Although high altitude has been suggested to create a prothrombotic state, virtually no studies have explored its clinical effects in lower extremity trauma. The purpose of this study was to compare surgical fixation of tibial plateau fractures at high and low altitudes and its effects on post-operative VTE development. Methods: The Truven MarketScan claims database was used to retrospectively identify patients who underwent surgical fixation of isolated and closed tibial plateau fractures using Current Procedural Terminology (CPT) codes over a 10-year period. Extraneous injuries were excluded using the International Classification of Diseases, 10^th edition (ICD-10), and CPT codes. Patient demographics, comorbidities, and DVT chemoprophylaxis prescriptions were obtained. Patients were partitioned into high altitude (>4000 feet) or low altitude (<100 feet) cohorts based on the zip codes of their surgery locations. One-to-one matching and univariate analysis were used to assess and control any baseline discrepancies between cohorts; multivariate regression was then performed between cohorts to determine the odds ratios (OR) for developing VTEs post-operatively. Results: There were 7,832 patients included for analysis. There was no statistical difference between high and low altitude cohorts in developing VTEs within 30 days post-operatively. Higher altitudes were associated with increased odds of developing DVT (OR 1.21, p = 0.043) and PE (OR 1.27, p = 0.037) within 90 days post-operatively. Conclusions: Surgical fixation of tibial plateau fractures is associated with an increased risk of developing VTEs at high altitudes within 90 days post-operatively. Understanding such risk factors in specific orthopaedic patient populations is essential for optimizing DVT prophylaxis protocols. Further studies should investigate this relationship and the role of DVT prophylaxis regimens in this population.