Date Published: June 30, 2017
Publisher: Public Library of Science
Author(s): Wei-Ju Chang, Kim L. Bennell, Paul W. Hodges, Rana S. Hinman, Carolyn L. Young, Valentina Buscemi, Matthew B. Liston, Siobhan M. Schabrun, Alessio Avenanti.
A randomised, assessor- and participant-blind, sham-controlled trial was conducted to assess the safety and feasibility of adding transcranial direct current stimulation (tDCS) to quadriceps strengthening exercise in knee osteoarthritis (OA), and provide data to inform a fully powered trial. Participants were randomised to receive active tDCS+exercise (AT+EX) or sham tDCS+exercise (ST+EX) twice weekly for 8 weeks whilst completing home exercises twice per week. Feasibility, safety, patient-perceived response, pain, function, pressure pain thresholds (PPTs) and conditioned pain modulation (CPM) were assessed before and after treatment. Fifty-seven people were screened for eligibility. Thirty (52%) entered randomisation and 25 (84%) completed the trial. One episode of headache in the AT+EX group was reported. Pain reduced in both groups following treatment (AT+EX: p<0.001, partial η2 = 0.55; ST+EX: p = 0.026, partial η2 = 0.18) but no between-group differences were observed (p = 0.18, partial η2 = 0.08). Function improved in the AT+EX (p = 0.01, partial η2 = 0.22), but not the ST+EX (p = 0.16, partial η2 = 0.08) group, between-group differences did not reach significance (p = 0.28, partial η2 = 0.052). AT+EX produced greater improvements in PPTs than ST+EX (p<0.05) (superolateral knee: partial η2 = 0.17; superior knee: partial η2 = 0.3; superomedial knee: partial η2 = 0.26). CPM only improved in the AT+EX group but no between-group difference was observed (p = 0.054, partial η2 = 0.158). This study provides the first feasibility and safety data for the addition of tDCS to quadriceps strengthening exercise in knee OA. Our data suggest AT+EX may improve pain, function and pain mechanisms beyond that of ST+EX, and provides support for progression to a fully powered randomised controlled trial.
Knee osteoarthritis (OA) is a prevalent and costly health problem with no known cure. Approximately 10% of people aged over 60 years experience significant pain, physical dysfunction and reduced quality of life as a result of knee OA, and this figure is rising rapidly . The development of low cost, non-drug, non-surgical treatments to improve patient outcomes has been identified as a key priority area by people living with OA .
This randomised, assessor- and participant-blinded, controlled trial was prospectively registered with the Australian and New Zealand Clinical Trials Registry: ACTRN12613001320741. Ethical approval was obtained from Western Sydney University’s Human Research Ethics Committee (H10184). All participants provided written informed consent.
This is the first study to investigate the addition of tDCS to a quadriceps strengthening exercise in knee OA. Our study demonstrates that this treatment combination is feasible and appears to be safe in this population. Further, our preliminary evidence indicates that adding tDCS to exercise may be a promising approach for improving pain, physical function and pain mechanisms in knee OA. These results provide data to inform a fully powered clinical trial to examine the effect of this novel treatment on the symptoms and pain mechanisms associated with knee OA.