Immediate clinical benefits of combining therapeutic exercise and interferential therapy in adults with chronic neck pain: a randomized controlled trial

Abstract

BACKGROUND: Therapeutic exercise (TE) is highly recommended for the management of non-specific neck pain (NSNP) and has shown promising results combined with interferential current therapy. Yet, the clinical relevance of the pooled effect of these approaches remains uncertain. AIM: To investigate the immediate clinical effect size of combining TE and interferential therapy, compared with the isolated use of TE, in adults with chronic NsNp. DESIGN: Randomized, single-blinded, controlled, superiority trial. sEttiNG: outpatients, primary care center. populatioN: forty-nine adults with chronic NsNp. METHODS: Participants with neck pain (grades I or II) lasting for more than 12 weeks were allocated to a TE plus interferential currents group (N.=25) or to a TE only group (N.=24). All individuals underwent treatment 5 times a week for 2 weeks. The primary outcome was current neck pain intensity (11-point Numeric Pain Rating Scale). Secondary outcomes included neck disability (Neck Disability Index) and active cervical range-of-movement (CROM device). Measurements were taken at baseline and immediately after treatment. An intention-to-treat analysis was carried out. To quantify the effect size of the interventions, the relative risk, the absolute and relative risk reduction, and the number needed to treat (NNt) were calculated. RESULTS: A significant time*group effect was found for pain intensity, disability, and neck flexion and right rotation (all, P<0.05). In the analy- sis for treatment benefit, the NNT was 2 (95% CI: 2 to 4, P<0.001) for neck pain and disability, and 3 (95% CI: 2 to 11, P=0.029) for neck flexion. CONCLUSIONS: Adding interferential therapy to TE is clinically more effective than TE alone to immediately improve neck pain and disabil- ity, but not active cervical range-of-movement, in adults with persistent neck pain. CLINICAL REHABILITATION IMPACT: Our results suggest that this multimodal intervention can be a useful strategy for rehabilitation of patients with NSNP. This is the first study on this topic reporting findings in terms of clinical relevance, which is key to transfer research evidence into practice.