A Study of Duloxetine (LY248686) in Participants With Chronic Osteoarthritis and Knee Pain in Japan

Inclusion Criteria: * Participants with present OA. * Have pain for ≥ 14 days of each month for 3 months prior to study entry. * Participants must have a score of ≥4 on the BPI average pain score before randomization. * Females of child-bearing potential must test negative (-) on a pregnancy test. Exclusion Criteria: * Participants who cannot appropriately complete the daily diaries. * Have a score change of ≧3 on BPI 24-hour average pain score between screening and baseline. * Participants who have serious cardiovascular, hepatic, renal, endocrine, respiratory, or hematologic illness, peripheral vascular disease, or other medical condition or neuropsychiatric conditions or clinically significant laboratory abnormalities or electrocardiographic abnormalities. * Participants who have alanine aminotransferase (ALT) or aspartate aminotransferase (AST) higher than 100 international units per liter (IU/L) or total bilirubin higher than 1.6 milligrams/deciliter (mg/dL). * Participants who have serum creatinine level higher than 2.0 mg/dL, or had renal transplantation or are receiving renal dialysis. * Participants who have a diagnosis of inflammatory arthritis (that is, rheumatoid arthritis) or an autoimmune disorder (excluding inactive Hashimoto's thyroiditis and Type 1 diabetes). * Participants who have any previous diagnosis of psychosis, bipolar disorder, or schizoaffective disorder. * Participants who have major depressive disorder as determined using depression module of the Mini-International Neuropsychiatric Interview (M.I.N.I.). * Participants who have uncorrected thyroid disease, uncontrolled narrow-angle glaucoma, history of uncontrolled seizures, or uncontrolled or poorly controlled hypertension. * Participants who have received intrarticular hyaluronate or steroids, joint lavage, or other invasive therapies to the knee in the past 1 month. * Participants who have had knee arthroscopy of the index knee within the past year or joint replacement of the index knee or osteotomy at anytime. * Participants who have end-stage osteoarthritis or surgery planned during the trial for the index joint. * Participants have a prior synovial fluid analysis showing a white blood cell (WBC) ≥2000 cubic millimeters (mm3) that is indicative of a diagnosis other than OA. * Participants taking any excluded medications that cannot be discontinued. * Participants anticipated by the investigator to require use of nonsteroidal anti-inflammatory drugs that include acetaminophe…