Hospital-acquired COVID-19 and deep vein thrombosis in orthopaedic inpatients: a retrospective cohort study in a resource-constrained setting

Background: Hospital-acquired COVID-19 presents a distinct challenge in orthopaedic care within low- and middle-income country (LMIC) settings, where prolonged isolation, delayed mobilization and system constraints increase immobilization-related morbidity. Unlike high-income settings that emphasize respiratory outcomes, LMIC orthopaedic inpatients appear to face a disproportionate burden of thromboembolic complications, particularly deep vein thrombosis (DVT). Methods: A retrospective cohort study was conducted at a South Indian teaching hospital between January 2020 and December 2025. Orthopaedic inpatients with RT-PCR–confirmed COVID-19 were categorized as having nosocomial or community-acquired infection based on timing of diagnosis. Demographic data, injury and treatment characteristics, immobilization duration, comorbidity burden, thromboprophylaxis use and vitamin D status were analysed. DVT was diagnosed using duplex ultrasonography and multivariable logistic regression identified independent predictors. Results: Of 217 patients (median age 48 years; 68.2% male), 68 developed nosocomial COVID-19. Hospital-acquired infection was associated with significantly longer hospital stay and immobilization. Overall DVT incidence was 11.1%, with a higher prevalence in nosocomial compared with community-acquired cases (19.1% vs. 7.4%). Nosocomial infection, immobilization exceeding seven days and vitamin D deficiency independently predicted DVT. In-hospital mortality did not differ between groups. Conclusion: Hospital-acquired COVID-19 significantly increases DVT risk among orthopaedic inpatients in LMIC settings, driven primarily by prolonged immobilization. Preventive strategies should prioritize early mobilization, optimized isolation workflows and correction of modifiable risk factors to reduce avoidable thromboembolic morbidity.