Topical Formulation of Tramadol 5% in the Management of Osteoarthritis of the Knee: A Double-Blind, Randomized, Prospective, Placebo-Controlled Clinical Trial

The goal of the present study was to evaluate the efficacy of topical tramadol in the management of knee osteoarthritis pain. Sixty patients with moderate to severe pain of knee osteoarthritis were enrolled. Patients were randomized to receive tramadol 5% or placebo along with oral diclofenac 100 mg/day. They were instructed to apply the ointment every 12 h on the knee for three weeks. To control breakthrough pain, the patients were allowed to take acetaminophen up to 650 mg per day. The measured variables were Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Visual Analog Scale (VAS). Sixty patients completed the study. At the end of follow-up period, VAS decreased by 21% (from 7.2 ± 2.1 to 5.7 ± 2.4, <i>p</i>-value < 0.05) and WOMAC score decreased by 23% (from 49.6 ± 17.4 to 38.4 ± 18.1, <i>p</i>-value < 0.05) in intervention group. Topical tramadol was significantly effective in reducing the intensity of pain and osteoarthritis symptoms in comparison to placebo considering VAS (5.7 ± 2.4 vs. 8.0 ± 2.9, <i>p</i>-value = 0.001) and WOMAC score (38.4 ± 18.1 vs. 46.0 ± 18.6, <i>p</i>-value = 0.007). Topical tramadol 5% appears to be effective in moderate to severe knee osteoarthritis pain.