Of 156 eligible trials, 114 (covering 22 treatments and 9,709 patients) provided data suitable for analysis. Most trials studied short-term effects and many were classed as being of poor quality with high risk of bias, commonly associated with a lack of blinding (which was sometimes impossible to achieve).
End of treatment results showed that eight interventions – interferential therapy, acupuncture, transcutaneous electrical nerve stimulation (TENS), pulsed electrical stimulation, balneotherapy, aerobic exercise, sham acupuncture, and muscle-strengthening exercise – produced a statistically significant reduction in pain, compared with standard care.
In a sensitivity analysis of satisfactory and good-quality trials, most were of acupuncture (11 trials) or muscle-strengthening exercise (nine trials); both these interventions were statistically significantly better than standard care, with acupuncture being significantly better than muscle-strengthening exercise (SMD 0.49, 95% CrI 0.00 to 0.98).