Microcurrent therapy in the treatment of knee osteoarthritis: could it be more than a placebo effect? A randomized controlled trial.

BACKGROUND

Microcurrent therapy (MCT) is a novel electrotherapy modality with very low current-levels that may reduce pain especially in joints and muscles.

AIM

The aim of this study is to explore potential effects of MCT on pain in patients with knee osteoarthritis, to explore effects of different treatment parameters and to distinguish them from placebo-effects.

DESIGN

Randomized four arms controlled clinical trial.

SETTING

Outpatient tertiary medical care center.

POPULATION

Fifty-six patients with knee OA (Kellgren-Lawrence Score II or III, 14 male and 38 female, mean age: 71.7±7.3 years, pain intensity higher than Numeric Rating Scale [NRS] score 3 from 10).

METHODS

Patients were randomized into four groups: MCT with 100 µA (group A), MCT with 25 µA (group B), sham-treatment (group C) and a control-group without intervention. Treatment groups received 10 sessions of MCT for 30 minutes each over a period of 22 days. The primary outcome was daily pain intensity throughout the treatment period measured by a NRS from 0-10. Second outcome measurements were the Knee Osteoarthritis Outcome Score (KOOS), the SF-36 Questionnaire, the Six-Minute Walking Test and the Get-Up-and-Go Test.

RESULTS

Evening pain was reduced significantly in the verum-groups compared to sham group (Group A vs. Group C: P<0.001, Group B vs. Group C: P=0.006) and to no intervention (Group A vs. Group D: P<0.001, Group B vs. Group D: P=0.002). The difference between sham-therapy and no therapy was not significant. In the pre-post analysis of the KOOS group A improved significantly in the subscale Symptoms. Group A and B and D improved in the Activities of Daily Living subscale.

CONCLUSIONS

The results of this RCT suggest that MCT has beneficial effects on pain in patients with knee osteoarthritis that are not explained by a placebo effect. Due to the explorative, pilot character of the study, further confirmation is needed before clear recommendations can be given.

CLINICAL REHABILITATION IMPACT

More high-quality RCTs with transparent parameters should be investigated to elucidate potential effects of MCT in the field of physical medicine and rehabilitation. At the present time MCT is a treatment option that could be helpful, in particular for patients who are afraid of unpleasant sensations from electrotherapy with stronger currents.