Optimal stimulation duration of tens in the management of osteoarthritic knee pain.
OBJECTIVE
This study examined the optimal stimulation duration of transcutaneous electrical nerve stimulation (TENS) for relieving osteoarthritic knee pain and the duration (as measured by half-life) of post-stimulation analgesia.


METHODS
Thirty-eight patients received either: (i) 20 minutes (TENS20); (ii) 40 minutes (TENS40); (iii) 60 minutes (TENS60) of TENS; or (iv) 60 minutes of placebo TENS (TENS(PL)) 5 days a week for 2 weeks.


METHODS
A visual analogue scale recorded the magnitude and pain relief period for up to 10 hours after stimulation.


RESULTS
By Day10, a significantly greater cumulative reduction in the visual analogue scale scores was found in the TENS40 (83.40%) and TENS60 (68.37%) groups than in the TENS20 (54.59%) and TENS(PL) (6.14%) groups (p < 0.000), such a group difference was maintained in the 2-week follow-up session (p < 0.000). In terms of the duration of post-stimulation analgesia period, the duration for the TENS40 (256 minutes) and TENS60 (258 minutes) groups was more prolonged than in the other 2 groups (TENS20 = 168 minutes, TENS(PL) = 35 minutes) by Day10 (p < 0.000). However, the TENS40 group produced the longest pain relief period by the follow-up session.


CONCLUSIONS
40 minutes is the optimal treatment duration of TENS, in terms of both the magnitude (VAS scores) of pain reduction and the duration of post-stimulation analgesia for knee osetoarthritis.
Cheing
Gladys L Y
GL
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. rsgladys@polyu.edu.hk
Tsui
Amy Y Y
AY
Lo
Sing Kai
SK
Hui-Chan
Christina W Y
CW
D000368:Aged; D000369:Aged, 80 and over; D000698:Analgesia / Q000379:methods; D000704:Analysis of Variance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000534:rehabilitation*; D010147:Pain Measurement; D017288:Pain Threshold; D017060:Patient Satisfaction; D011336:Probability; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D012720:Severity of Illness Index; D013997:Time Factors; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D016896:Treatment Outcome