The analgesic effect of interferential therapy on clinical and experimentally induced pain

Background: Interferential therapy (IFT) is one of the most popular modalities used by physiotherapists for the management and control of pain. Despite its widespread use, there remains debate surrounding its effectiveness. Objectives: The aim of this systematic review was to evaluate the published literature on the effectiveness of IFT in reducing pain. Method: A literature search of Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval System Online (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Excerpta Medica Database (EMBASE), and Physiotherapy Evidence Based (PEDro) was performed. This review adhered only to randomised controlled trials (RCTs) that investigated IFT in the presence of a control group. PEDro scale was used to assess the methodological quality of the included studies. Results: Nine RCTs met the inclusion criteria of this review. One study evaluated the effect of IFT on clinical pain while remaining studies examined induced pain including thermal (cold and hot), ischemic, mechanical, and delayed onset of muscle soreness. No clear conclusion was withdrawn regarding the effectiveness of IFT on pain management due to the high variability in study design and deficiencies in methodological quality. The data were limited and contradicting and therefore, of equivocal support to the pain reduction effect of IFT. Conclusion: There is inadequate evidence to support the effectiveness of IFT in pain management. Clearly, there is a need for RCTs with high methodological quality to establish IFT efficacy.