Dorais M, et al. - Using the Osteoarthritis Initiative (OAI) database, researchers measured the association between exposure to commonly used oral osteoarthritis (OA) therapies and relevant risk factors on the occurrence of knee replacement (KR). In this nested case-control design study, “cases” were the participants who had a KR after cohort entry and these were matched with up to four controls for age, gender, income, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, Kellgren-Lawrence grade, and duration of follow up. Evidence suggested that disease severity, symptoms, and high body mass index (BMI) were the main risk factors leading to KR. They saw no correlation of exposure to oral OA therapies with the occurrence of KR.