Sample size
knee pain, pain
The sample size was based on the primary outcome measure of this trial (0–10 NRS knee pain). That is, based on an expected between-group difference of 0.5 on the 0–10 NRS pain scale, an estimated standard deviation (SD) of 1.4, α=0.05 (2-sided testing), power=90%, design effect of 1.05 and a 15% drop-out rate, 408 participants (204 per group) were desired.