Stochastic resonance electrical stimulation to improve proprioception in knee osteoarthritis.

Proprioceptive deficits occur with knee osteoarthritis (OA) and improving proprioception may slow joint degeneration by allowing more appropriate joint loading. Stochastic resonance (SR) stimulation improves balance and the sensitivity of specific mechanoreceptors. Our purpose was to evaluate the effects of SR electrical stimulation combined with a knee sleeve on proprioception in subjects with knee OA. Joint position sense (JPS) was measured in 38 subjects with knee OA during four conditions in both a partial weight-bearing (PWB) and non weight-bearing (NWB) task: no electrical stimulation/no sleeve, no electrical stimulation/sleeve, 50 μA-RMS stimulation/sleeve, and 75 μA-RMS stimulation/sleeve. Subjects also reported their knee pain, stiffness, functionality (WOMAC), and instability. Repeated measures ANOVA and Spearman correlations were performed to investigate differences between the conditions and relationships among the outcome measures. JPS during the 75 μA-RMS stimulation/sleeve and sleeve alone conditions was significantly improved compared to the control condition in the PWB task. However, the 75 μA-RMS stimulation/sleeve and the sleeve alone conditions did not differ from each other. A moderate correlation was found between the improvements with the 75 μA-RMS stimulation/sleeve condition compared to the JPS of the control condition in the PWB task. No differences in JPS were found between the four conditions in the NWB task. Significant correlations were found between the control JPS and WOMAC indices (p<0.005). Improved proprioception during the PWB task was achieved with a sleeve alone and in combination with SR stimulation. The observed correlations suggest that subjects with larger proprioceptive deficits may benefit most from these therapies.