Effects of Whole-Body Vibration Therapy on Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

No trial blinded the participants or the therapists, and the outcomes that improved most (pain and self-reported function) are exactly the ones people can shift when they know they are using the active machine. The authors say the optimal vibration regimen is unclear: trials varied from 5 to 40 Hz, from 4 to 24 weeks, with different amplitudes and weekly exposure times. Balance, chair stand and gait speed were pooled from very few studies and fewer than 100 participants, and the 6-minute walk result had high heterogeneity between trials. Several results have wide confidence intervals that cross zero, including 6-minute walk distance, balance, chair stand, gait speed and isokinetic peak torque. Only 10 of the 14 trials could be pooled, and the largest single trial was excluded because of missing data. The review protocol was not registered, so the planned analyses cannot be checked against what was reported, and results were not analysed separately for men and women. All trials scored 4 or more out of 10 on the PEDro quality scale, but none scored better than 8.

The authors declare they have no conflicts of interest. No funding source is reported in the article text supplied.

Do not read this as showing that vibration works on its own for knee osteoarthritis. Every pooled trial added whole-body vibration to a strengthening exercise programme and compared it with that same programme, so vibration alone was never tested, and its contribution cannot be separated from the exercise. Also note that no trial blinded the patients or the therapists, and the outcomes that improved most were self-reported pain and function.