Terpstra SES, van der Velde JHPM, de Mutsert R, et al. - This study was undertaken to explore knee osteoarthritis (OA) is associated with lower physical activity in the general middle-aged Dutch population, and if physical activity is associated with patient-reported outcomes in knee OA. Researchers defined clinical knee OA in the Netherlands Epidemiology of Obesity population using the ACR criteria and structural knee OA on MRI. Researchers evaluated knee pain and function with the Knee Injury and Osteoarthritis Score, health-related quality of life (HRQoL) with the Short Form-36, and physical activity (in Metabolic Equivalent of Task (MET) hours) with the Short Questionnaire to evaluate Health-enhancing physical activity. They further examined the relationships of knee OA with physical activity, and of physical activity with knee pain, function, and HRQoL in knee OA with linear regression adjusted for potential confounders. It was shown that knee OA was not correlated with lower physical activity, and in knee OA physical activity was not correlated with patient-reported outcomes. There is a need for further study to evaluate the optimal treatment advice regarding physical activity for individual knee OA patients.