Palmer 2007.

Trial name or title	ISRCTN12912789
Methods	A randomised, sham‐controlled trial with 3 parallel arms Randomisation method: not reported Concealment of allocation: not reported Blinding: not reported Sample size calculation: not reported Analyses: not reported whether is based on intention‐to‐treat principle Trial duration: 6 weeks Sponsored by: not reported
Participants	261 (87 in each arm) patients with primary knee OA to be randomised Study joints: knees Selection criteria: knee pain, radiographic (X‐ray) evidence of osteophytes, and at least 1 of the following 3 criteria: 50 years or older, morning stiffness that lasts for less than 30 minutes, crepitus on active movement
Interventions	Experimental intervention: TENS, as much as needed and group education including self‐efficacy and exercise training, once per week Control intervention 1: Sham TENS, as much as needed and group education once per week, as described above Control intervention 2: group education once per week, as described above Duration of treatment period: 6 weeks Analgesics: unclear wether analgesic intake is allowed and is measured Device: not reported Self‐administered: yes Waveform: not reported Pulse width: not reported Pulse frequency: not reported Amplitude: "strong but comfortable" tingling sensation Duration of stimulation: defined as "as much as needed" Electrodes: not reported Electrode placement: within or close to the site of pain Sham device: identical in appearance, displays are active but there is no current output
Outcomes	Primary outcome: WOMAC function subscale (at baseline, 3, 6, 12 and 24 weeks) Secondary outcomes: 1. Total WOMAC score and WOMAC pain and stiffness subscale scores (at baseline, 3, 6, 12 and 24 weeks) 2. Knee extensor torque (quadriceps strength) (at baseline, 3, 6, 12 and 24 weeks) 3. Patient global assessment of change (at 3, 6, 12 and 24 weeks) 4. Self‐efficacy for exercise (at baseline and 24 weeks) 5. Self‐reported exercise adherence (at baseline, 3, 6, 12 and 24 weeks) 6. Logged TENS usage time (at 6 weeks)
Starting date	1 October 2007
Contact information	Dr Shea Palmer Faculty of Health and Social Care University of the West of England Blackberry Hill Bristol BS16 1DD United Kingdom Tel  +44 (0)117 328 8919 Email  Shea.Palmer@uwe.ac.uk
Notes	Status at 17 July 2009: completed at 30 June 2009

OA = osteoarthritis 
 TENS = transcutaneous electrical nerve stimulation 
 VAS = visual analogue scale