The effect of Trans-cutaneous Electrical Nerve Stimulation (TENS) on range of motion and morning stiffness of knee joint on patient with knee osteoarthritis

Osteoarthritis is the most prevalent human joint disease and knee joint is the most common joint, which is affected in the disease. The most common signs of this disease are reducing of motion range and morning stiffness of knee joint. Therefore, this study was conducted to assess the effect of TENS technique, as a non-pharmacological therapy, on range of motion and morning stiffness of knee joint on patients with knee osteoarthritis. In this quasi-experimental and single blind study, a total of 57 patients with knee osteoarthritis who referred to Imam Khomeini hospital in Tehran in 2005 were randomly divided into two groups of case (29) and control (28). TENS technique (110 Htz) was administered to the case group for 4 weeks (3 times a week for 20 minutes). Then, range of motion and morning stiffness of knee joint measured in different times during the intervention in this group. The same situation was used for the control but with turn-off system (Placebo). Range of motion and morning stiffness of knee joint was measured in the two groups in the first season (beginning), sixth session and at the end of study. Data were analyzed using analysis of variance, KV, and t tests. The mean of motion range in the case group was 82.2±2.26 before intervention, and increased to 89.7±3.07 and 117±4.5 at the sixth session and at the end of intervention, respectively (p<0.001). In the control group, the mean of this parameter in different times of intervention was not significant. Moreover, in the two groups, there was not significant difference in joint morning stiffness in different times of intervention. Based on the results, TENS technique affects remarkably on range of motion with no effect on morning stiffness of knee joint in patients with osteoarthritis. Thus, this method would increase range of knee motion in patients with osteoarthritis.