45 patients with symptomatic osteoarthritis of the knee joint were randomized to receive 4 weeks of active capacitive resistive monopolar radio frequency (CRMRF), sham CRMRF treatment, or standard-of-care treatment. The outcomes of interest included pain on a Visual Analog Scale (VAS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the time up and go (TUG) test and knee range of motion (ROM). Follow up was performed upon completion of treatment, 1 month after treatment and 3 months after treatment. Results revealed a significant effect of treatment type on VAS pain scores, WOMAC scores and knee range of motion. Significantly favourable VAS pain score and WOMAC scores were observed in the active CRMRF group compared to the sham and control groups.