Radiofrequency-based treatment in therapy-related clinical practice – a narrative review. Part II: chronic conditions

Background: Radiofrequency (RF)-based electrophysical agents (EPAs) have been employed in therapy related clinical practice for several decades. They are used to reduce pain and inflammation and promote tissue healing. Although deemed less popular in current therapy practice, surveys suggest that some of these EPAs are still used reasonably widely. Objective: To review the evidence for the use of non-invasive low-frequency RFs (30kHz - 30 MHz) for treating chronic therapy-related clinical conditions. Major findings: All relevant peer-reviewed clinical studies published in English, concerning low-frequency RFs were sought. Identified literature was stratified as ‘acute’ and ‘chronic’ based on their clinical area. The studies on chronic conditions were reviewed for this paper and analysed to assess the volume and scope of current evidence. Out of 120 studies identified, 90 related to chronic conditions. The majority of them (82 studies) employed shortwave therapy (SWT) in continuous (CSWT) or pulsed (PSWT) modes. Only eight studies employed frequencies other than shortwave. Overall 67 studies investigated conditions relating to ‘pain and inflammation’, 16 to ‘tissue healing’ and 7 studies to other less reported conditions. Conclusions: Evidence favouring and against RF-based EPAs is available. There is moderate evidence favouring the use of SWT (mainly PSWT) in knee osteoarthritis. Some evidence also exists for CSWT in chronic low back pain and PSWT for treating chronic wounds. Evidence for other conditions is insufficient and conflicting. A general lack of research emphasis in the non-shortwave RF band is evident. Further and wider research in this area is necessary.