Table 2.

Characteristics of trials of TENS for pain relief in patients with knee osteoarthritis

First author, publication year	Type	No of patients on active therapy (n = 259)	Method quality	Treat-ment period (weeks)	Mean baseline pain (mm VAS)	Best mean difference (95% CI) of change over placebo (mm VAS)	Outcome time points (in weeks, max. effect in bold)
Adedoyin-03	IF	15	3	4	81.0	25.4 (8.2 to 42.6)	1, 2, 3,4
Cheing-02	TENS	16	4	2	-	8.4 (0.7 to 16.1)	2, 4
Cheing-03	TENS	30	3	2	50.3	32.2 (23.9 to 40.5)	4, 8
Defrin-05	IF	45	4	4	71.0	41.6 (33.4 to 49.8)	4
Fargas-Babjak-89	TENS	19	3	12	-	45.3 (11.7 to 78.9)	6, 12
Law-05	ALTENS/TENS	27	4	2	57.3	29.7 (7.6 to 51.3)	2, 4
Lewis-84**	TENS	29	3	3	-	7.0 (-5.6 to 19.6)	3
Lewis-94**	TENS	28	1	3	-	4.9 (-8.4 to 18.3)	3
Smith-83	TENS	15	3	4	-	dichotomous data only	4
Taylor-81**	TENS	10	2	2	-	5.5 (-7.3 to 17.8)	2
Yurtkuran-99	ALTENS	25	3	2	-	20.0 (14.1 to 25.9)	2
Best within 4 weeks, all trials		223				18.8 (9.6 to 28.1)
Best within 4 weeks, optimal trials		156				22.2 (18.1 to 26.3)
8 weeks		30				8.3 (-1.1 to 17.6)
Global improvement 8 weeks		15				1.8 (0.6 to 4.8) Relative Risk
Overall		259	3.3*		63.8†		2.8*

*Mean † Weighted mean – Not Available ** Trials with non-optimal treatment