Fifty-two patients with acute knee pain were randomized to receive 4 weeks of daily microcurrent therapy (3 hours/day; n=26) or placebo microcurrent therapy (n=26) for the improvement of function and relief of pain. Outcomes of interest included pain severity on a Numeric Pain Rating Scale (NPRS) and physical scores of the Short-Form 12 (SF-12) quality of life questionnaire. Outcomes were assessed at 1, 2, 3, and 4 weeks follow-up. Results revealed a statistically significantly greater change from baseline for NPRS worst pain scores in the active group compared to the placebo group at weeks 2, 3, and 4 (p<0.05 for all). In the analysis controlling for age (young/middle-aged/older) and BMI, it was found that the older age group reported a significantly higher reduction in NPRS worst pain. Moreover, for SF-12 physical scores, the active group reported an increasing trend of improvement from baseline up to 3 weeks follow-up, whilst the placebo group reported a decreasing improvement from baseline.