Kumaran B1, Watson T1
1University of Hertfordshire, Hatfield, United Kingdom

Background: Osteoarthritis (OA) is the commonest form of arthritis among people of all ethnicities and a leading condition affecting function and quality of life (QoL) among middle-aged and older adults. With a rapidly growing evidence-base for OA management, updated clinical guidelines emphasise on the importance of non-drug non-surgical treatments such as physiotherapy. Half of all non-pharmacological interventions suggested by European League against Rheumatism (EULAR) as potential interventions for OA knee are electrophysical agents (EPAs). Some of these EPAs employ radiofrequency (RF) currents. Besides shortwave therapy (SWT) that commonly operates at 27.12 MHz, other RF-based EPAs employing significantly lower operating frequencies ( 1 MHz) have also been reported, despite their evidence base being minimal. Capacitive Resistive Monopolar Radiofrequency (CRMRF) that operates at 448 kHz is one such device.

Purpose: This study investigated whether CRMRF-based treatment improves pain and function among patients with osteoarthritis of the knee.

Methods: A three-group randomised controlled trial was conducted with concealed allocation and participant blinding. Forty-five patients diagnosed with osteoarthritis, from the waiting list for physiotherapy at a local hospital were enrolled. 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. Pain and function were measured on four occasions: week zero (baseline), week four (post intervention), week eight (follow-up 1) and week 16 (follow-up 2) 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). The group data were compared on an intention to treat basis using a mixed model analysis of variance (ANOVA) at baseline, post treatment, one-moth follow-up and three months follow-up between the active, sham, and control groups. Where assumptions of normality and/or equality of variances were not met, square root transformation of the data was performed before the analysis. The statistical significance was set at p ≤ 0.05 (0.8 P, 95% CI). The treatment effect sizes were determined using the Hedges' g.

Results: Both pain (VAS) and WOMAC function scores showed significant changes over time within and between groups. For pain, there were clinically significant changes in the active group at post treatment compared to sham (effect size: 1.3, 95% CI: 0.29-1.3) and control (effect size: 1.5, 95% CI: 0.32-1.3), and at one-month follow-up compared to control (effect size: 1.1, 95% CI: 0.10-1.3). For function (WOMAC), there was clinically significant change in the active group at post treatment compared to control (effect size: 0.94, 95% CI: 0.02-2.6), 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(s): CRMRF treatment can significantly improve pain and function in patients with knee osteoarthritis in the short term.

Implications: The study informs clinical practice by highlighting the potential benefits of this relatively underused RF-based EPA in the management of OA knee. The study also provides baseline data for future research.

Keywords: Electrophysical agents, Radiofrequency treatment, Knee osteoarthritis

Funding acknowledgements: The University of Hertfordshire were in receipt of an industry-linked research funding from Indiba S. A., Barcelona for this work.

Topic: Musculoskeletal: lower limb

Ethics approval required: Yes
Institution: NHS HRA
Ethics committee: NRES Committee North West - Greater Manchester South
Ethics number: 15/NW/0529

All authors, affiliations and abstracts have been published as submitted.

Back to the listing