RecruitingPhase 4Drug trialBrain-Based and Clinical Phenotyping of Pain Pharmacotherapy in Knee OsteoarthritisThis is a clinical trial of people who have pain due to knee osteoarthritis at Northwestern University Feinberg School of Medicine. The study will last for about 20 weeks. 180 qualified participants will be randomly assigned in a 1:1:1 ratio (60 participants per group) to one of three treatment groups: duloxetine, celecoxib, or placebo. Participants will have a knee Xray, (optional) MRIs of the brain and knee, blood draws, pain sensitivity testing, and asked to fill out questionnaires. The purpose of this study is to try to predict which participants will respond to the treatment.