IRCT201609143014N14 IRCT 2016-12-22 Vice Chancellor for Research of Mazandaran University of Medical Sciences Study of analgesic effects of topical tramadol on Osteoarthritis pain Study of analgesic effects of topical tramadol 5% on Osteoarthritis pain: A randomized, placebo control, double blind clinical trial 2016-09-22 anticipated 60 Complete https://irct.ir/trial/2968 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Other design features: Randomization is done using random number table. We give a code number to each patient that shows the group each patient is allocated to. The list of patients and their code numbers is kept secret until the end of the trial. In this way neither the patient nor the researchers know whether it is drug or placebo. N/A Osteoartritis. Intervention 1: Intervention: Tramadol 5% cream, twice daily for one month. Intervention 2: Control: Cream without active ingredient, twice daily for one month.