Would the addition of TENS to exercise training produce better physical performance outcomes in people with knee osteoarthritis than either intervention alone?

Objective: To examine if the addition of transcutaneous electrical nerve stimulation (TENS) to exercise training would produce better physical outcomes than TENS or exercise alone in people with knee osteoarthritis. Design: Sixty-two subjects were randomly allocated to four groups. Interventions: Patients received either (1) TENS, (2) placebo stimulation, (3) exercise training, or (4) TENS and exercise training five days a week for four weeks. Main outcome measures: The isometric peak torque, spatiotemporal gait parameters and range of knee movement were assessed in treatment session(1), session(10) and session(20) and the four-week follow-up. Results: By session(20), the TENS and exercise group demonstrated an average of 26.6% cumulative gain in the knee extensor peak torque for the different knee positions (all p<0.05). Although the between-group difference was short of being statistically significant, the gain found in the TENS and exercise group was greater than that found in the other three groups. The TENS and exercise group also tended to show greater cumulative increase in stride length (12.6%, p=0.006), walking cadence (9.3%, p=0.098) and gait velocity (22.4%, p=0.034) than the other groups. By session(20), it was the only group that produced a significant increase in the range of knee motion during walking (12.0%, p=0.000). The TENS group and the exercise group both demonstrated some improvements in the above physical outcomes, but negligible change was found in the group receiving placebo stimulation (all p>0.05). Conclusion: No significant difference was found among the four treatment protocols, but the addition of TENS to exercise training tended to produce the best overall improvement in physical outcomes in people with knee osteoarthritis.