Effect of national COVID-19 lockdown on the incidence of muscle, tendon and ligament injuries and related surgical procedures in the working-aged Finnish population

Introduction: The effect of lockdown on the incidence of fractures and severe injuries has been widely studied, whereas studies regarding muscle, tendon, and ligament injuries have not received as much attention. The aim of the study was to investigate the effect of the lockdown and later regional regulations due to the COVID pandemic on the incidence of muscle, tendon, and ligament injuries and related surgical procedures. Materials and methods: This study focuses on the working-age population in the catchment areas of three major Finnish hospitals. Patients were divided into three age groups 18–34, 35–50 and 51–65 years of age. Suitable injuries were retrieved from the data using appropriate ICD-10 codes and procedure codes. The monthly incidence rate ratio (IRR), with 95% confidence intervals (CI), were compared between the year 2020 and the reference years 2017–2019. Results: Upper and lower extremity injury ED visits decreased by 15.7 and 8.2%. For upper extremity injuries, a decrease in incidence was observed for all three age groups in March (IRR 0.52, CI 0.33–0.80), (IRR 0.53, CI 0.31–0.91), (IRR 0.60, CI 0.38–0.95), respectively. An increase in 18–34 years of age group was detected in June (IRR 1.49, CI 1.05–2.13). Lower extremity injuries decreased in 18–34 years of age group in March (IRR 0.62, CI 0.43–0.90) and April (IRR 0.60, CI 0.42–0.87). A decrease on the incidence of surgeries was observed in April for the 35–50 (IRR 0.53, CI 0.29–0.97) and 51–65 years of age groups (IRR 0.58, CI 0.34–0.98). Conclusions: The nationwide lockdown in spring 2020 led to a notable decrease in the incidence of emergency department visits and the surgical treatment of muscle, tendon, and ligament injuries in Finland.