Physical therapist-delivered acceptance and commitment therapy and exercise for older outpatients with knee osteoarthritis: a pilot randomized controlled trial.

Only 30 participants were analysed in a single centre, and 27 were women, so results may not apply to other older knee osteoarthritis populations. Half of participants dropped out: eight of 15 in the ACT plus exercise group and seven of 15 in usual care completed the study. The trial was open-label, and the paper states grouping randomization was not blinded or stratified, so measurement and intervention effects may be biased. The exercise dose was once weekly for 30 minutes, while the authors note previous studies used at least 2-3 times a week for 20-30 minutes to affect physical function. The physical therapist delivering ACT had only a 6-hour 3-day training, no ongoing clinical psychologist support during the intervention, and no private room was provided. Missing data were handled by last measured value under intention-to-treat, but the authors say the results were not fully reflected.

The authors declare no conflict of interest.

Do not read this as proof that ACT adds benefit to exercise. The main comparison of groups over time was not significant (p=0.09), half of participants dropped out, and the between-group difference at 4 weeks came from comparisons after the main test in a small pilot.