RANDOMISED PLACEBO-CONTROLED TRIAL ON EFFICACY OF DYNAMIC ELECTRONEUROSTIMUL. IN KNEE OSTEOARTHRITIS

Lesnyak O. Randomized placebo-controlled trial on efficacy of dynamic electroneurostimulation in knee osteoarthritis / O. Lesnyak, E. Kadochnikova, A.Vlasov // 16 European Congress of Physical and Rehabilitation Medicine. - Brugge, Belgium . - 2008.-р. 70-71.

RANDOMISED PLACEBO-CONTROLED TRIAL ON EFFICACY OF DYNAMIC ELECTRONEUROSTIMULATION IN KNEE OSTEOARTHRITIS

O. Lesnyak, E. Kadochnikova, A. Vlasov
Ural State Medical Academy, Dept. of Family Medicine, Yekaterinburg, Russia

Aim

Knee osteoarthritis (OA) is the most common form of arthritis in elderly. It is a chronic disorder which causes pain, functional impairment and disability.To date, no curative treatment for OA exists. Efforts aimed at reducing the pain and functional impairment due to OA are part of the tertiary prevention of joint damage. Transcutaneous electrical nerve stimulation (TENS) is a noninvasive modality that is commonly used in physiotherapy to control both acute and chronic pain arising from several conditions. It has been demonstrated that TENS is effective in controlling pain due to knee OA.1 Dynamic electroneurostimulation (DENS) is a new method of TENS. Sinusoidal form of impulse developed by DENS devices depends on and changes according to changing of skin surface resistance in subelectrode zone. DENS device chooses the exact form of the impulse which is specific for the particular zone of the particular subject. The aim of this study was to investigate the efficacy of DENS in pain relief and joint function in knee OA.

Methods

This was a randomized double-blinded, placebocontrolled trial. Outpatients of both sexes aged 40-80 years who fulfilled the American College of Rheumatology criteria for knee OA and who had a knee pain more than 40 mm on visual analogue scale (VAS) were randomly assigned to 10 standard daily procedures of DENS or placebo-DENS.

Patients with cardio stimulator, acute infection, cancer, skin problems near the knee, uncontrolled arterial hypertension, intensive pain of other origin as well as drug abused patients were excluded from the study. Applicator connected to DiaDENS-PC apparatus was fixed at the knee area. Parameters of stimulation were following: frequency 77 Hz, current strength 8 to 12 mA, duration 30 min. An imitation of DENS-effect was created in placebo group with the help of DiaDENS-PC apparatus-placebo. By analogy with DiaDENS-PC a notice “77 Hz Therapy” was seen on the screen of apparatus. However, the medical effect was not realized. Basing on their sensations patients of both groups could not understand which apparatus they were treated with. Outcome measures were as follows: pain scored on a 100-mm to VAS, joint mobility according to range of movement and physical ability (test “stand and go”, s/5 m).

The symptoms of OA were assessed before and after the procedure by the independent investigator during 1, 3, 6 and 10 days of treatment. The most symptomatic joint was selected as the study target knee. All patients gave their informed consent to participate in the study.

Results

A total of 58 knee OA patients were included (56 females and 2 males): 30 in the DENS group and 28 in the placebo-DENS group. The groups did not differ in age and main clinical features of OA (Table I). Intensity of pain decreased during the treatment in DENS group (Ptrend=0.0001) and did not change in placebo group (Ptrend=0.133). The difference between DENS and placebo groups on VAS pain score became statistically significant at the VI day of treatment (P=0.003). At the end of the treatment VAS pain score was 38.7 mm (95%CI 33.6; 43.8) in the DENS group and 62.0 mm(95% CI 54.8; 69.2) in the placebo-DENS group (P<0.0001). The “stand and go” test significantly improved in DENS group (Ptrend=0.001) and was almost stable in placebo-DNS patients (Ptrend=0.644). The difference between DENS and placebo-DENS was statistically significant at X day of treatment: 9.8 s (95% CI 9.10; 10.50) in the

Table I
Demographic and clinical characteristics of the 58 study patients at baseline.

BMI: body mass index; DENS: dynamic electroneurostimulation; VAS: visual analogue scale.

DENS group and 11.43 s (95% CI 10.67; 12.19) in the placebo-DENS group (P=0.001). Joint mobility did not differ between treatment groups during the whole study (P=0.071), although the tendency to improvement was noted in the DENS group (Ptrend=0.066) but not in the placebo (Ptrend=0.862). Based on the differences between symptoms before and after each procedure (P=0.072 for pain relief, P=0.481 for physical ability) there was no tendency to diminishing of DENS effect during the treatment. This is the first randomized doubleblinded, placebo-controlled study to assess the efficacy of the new method of TENS in knee OA, which is called DENS due to its effect on reflexogenous zones and acupuncture points through different electric impulses. The form of the impulse depends on the impedance of the skin surface in subelectrode area. Our study showed that at the end of the treatment (10 procedures), pain and patients’ physical ability significantly differed between DENS and placebo-DENS groups. Thus, DENS was superior over placebo in pain relief and physical function in knee OA. The improvement in physical ability might be secondary to pain reduction on DENS therapy. The range of movement at the knee did not differ in two study groups, although the tendency to improvement was mentioned in the DENS group, and no change was found in the placebo-DENS group. The DENS effect did not diminish during the treatment. Further studies are needed to confirm these findings and to evaluate the duration of the persistence of this effect, its impact on need for NSAIDs and patients quality of life.

Conclusion

Presemt data suggest that DENS therapy has an obvious symptomatic effect in knee osteoarthritis as compared to placebo. The difference became statistically significant at sixth-tenth procedure.

References

1. Osiri M., Brosseau L., McGowan J., Robinson V.A., Shea B.J., Tugwell P. et al. Transcutaneous electrical nerve stimulation for knee osteoarthritis. The Cochrane Database of Systematic Reviews 2000, Issue 4. Art. No.: CD002823. DOI: 10.1002/14651858.CD002823.