Treatment using 448 kHz capacitive resistive monopolar radiofrequency improves pain and function in patients with osteoarthritis of the knee joint: a randomised controlled trial

Abstract Objective This study investigated whether capacitive resistive monopolar radiofrequency (CRMRF)-based treatment improves pain and function among patients with osteoarthritis of the knee. Design and setting Three-group randomised controlled trial with concealed allocation, participant blinding and intention-to-treat analysis. Forty-five patients diagnosed with osteoarthritis, from the waiting list for physiotherapy at a local hospital were enrolled. Intervention Participants in the active and sham groups received eight sessions of CRMRF and sham-CRMRF respectively over four weeks, along with standard care. The control group received standard care only. Assessment Pain and function were measured at four time points: week zero (baseline), week four (post intervention), week eight and week 16 (two follow-ups) using visual analogue scale (VAS), Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, timed up and go (TUG) test and knee range of motion (ROM). Results For pain (VAS), there were clinically significant changes in the active group at post treatment compared to sham (Mean difference: 0.79 (95% CI: 0.29 to 1.3), effect size: 1.3) and control (Mean difference: 0.82 (95% CI: 0.32 to 1.3), effect size: 1.5), and at one-month follow-up compared to control (Mean difference: 0.68 (95% CI: 0.10 to 1.3), effect size: 1.1). For function (WOMAC), there was clinically significant change in the active group at post treatment compared to control (Mean difference: 1.3 (95% CI: 0.02 to 2.6), effect size: 0.94), but not compared to sham. No meaningful differences were noted for TUG or knee ROM. No differences were noted at three-month follow-up for any outcomes. Conclusion CRMRF treatment can improve pain and function in patients with knee osteoarthritis in the short term. Trial registration: NIHR-CRN study ID: 20264.