IRCT20151017024572N23 IRCT 2020-08-01 Iran University of Medical Sciences Ultrasound-guided Prolotherapy, Oxygen-ozone and corticosteroid injection for treatment of knee osteoarthritis Ultrasound-guided Prolotherapy, Oxygen-ozone and corticosteroid injection for treatment of knee osteoarthritis: A randomized, double-blind, multi-center study. 2020-08-21 anticipated 42 Complete https://irct.ir/trial/20703 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: Participants will be randomly divided into three treatment groups using a table of random numbers and a centralized randomization method. In order to execute the randomization process to create a random sequence and to perform the random allocation process we will use RAS software which will be created by statisticians. Two hours before the patient's visit for injection, the person responsible for injection will contact the statistician by phone or text message and will ask her about the random assignment of the participant to a specific group, Blinding description: The injection material is prepared in the syringe without informing the patient and the syringes will be covered with an aluminum foil so that the participant does not know the type of injection material. Patients will be prohibited from receiving any NSAIDs or analgesics for a 15-day wash-out period prior to enrollment and intervention. Due to the different nature of ozone (gas), during the injection, there is a possibility that the injector will acknowledge the nature of this medical substance. The person responsible for outcome measures and the person responsible for the statistical analysis are also kept blind. 3 Osteoarthritis of knee. Intervention 1: Intervention group one: Corticosteroid, 40 mg Methylprednisolone, one time injection inside knee joint at suprapatellar recess. Intervention 2: Intervention group: Intervention group two: Ozone (O2-O3), 12 micro-gram, one time injection inside knee joint at suprapatellar recess. Intervention 3: Intervention group three: Prolotherapy (Dextrose 20 %), one time injection inside knee joint at suprapatellar recess. No - There is not a plan to make this available Justification or reason for not sharing IPD is Data will only be provided for journal during manuscript submission or for meta-analysis at the specific request of other individuals.