Epidemiology of knee osteoarthritis during the COVID-19 pandemic

Osteoarthritis of the knee, otherwise known as gonarthrosis, accounts for more than 80% of all degenerative joint diseases. Degenerative changes alone affect 80% of the population aged 75 years and older. Currently, 2 public health trends are believed to be the dominant factors in the development of gonarthrosis: increasing body mass index (BMI) and increasing age of the population. Both of these factors are also significant risk factors in the development of life-threatening complications with COVID-19 infection. This retrospective study collected the number of patients admitted to a trauma and orthopedic clinic at one time between 2019–2021 along with isolating the number of patients with a diagnosis of gonarthrosis (M17). In both cases, the results show a significant decrease in the number of patients admitted in the 2nd quarter (Q2) of 2020 and a decrease in overall patient admissions compared to the COVID-19 outbreak in Poland (31.25% decrease from 2019 to 2020). A significant impact on the decrease in the number of patients in Q2 2020 may have been the closure of the outpatient clinics from March 16, 2020 to August 16, 2020. Other factors influencing the subsequent decrease in patients may have been people’s fear of contracting COVID-19, decreased physical activity, worsening dietary habits, and weight gain during the “lockdown”. A review of recent studies on this topic may support this hypothesis.