After obtaining written informed consent and ethics committee approval, 100 patients aged 20-70 years with osteoarthritis having knee pain over 3 months are recruited to the randomized, double-blind study. Exclusion criteria are a chronic knee pain caused by infection, inflammation, tumors, and fractures or a history of acute knee pain, previous knee surgery, connective tissue diseases, neurologic or psychiatric disorders, administration of steroids or hyaluronic acids within the last three months, coagulation disorders and local infection at the site of intervention planned.