Pan F, et al. - Authors identified the distinct pain trajectories over 10.7 years and examined the predictors of identified pain trajectories in an older population and those with radiographic knee osteoarthritis (ROA). Homogeneous subgroups exist, which might be useful for phenotypic assessment for pain management, particularly in knee osteoarthritis; as seen on the distinct pain trajectories identified. Findings suggested an association of structural pathology with worse pain trajectories, thereby, suggesting that for the development and maintenance of pain severity, peripheral stimuli are critical. Pain perception may be exacerbated by the environmental and psychological factors.