Objectives: To investigate the short-term efficacy of repetitive peripheral magnetic stimulation (rPMS) on pain reduction in knee osteoarthritis.

Study design: Randomized controlled trial.

Setting: Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.

Subjects: Knee osteoarthritis patients with Kellgren-Lawrence classification (KL) 2-4 and Visual analog scale (VAS) > 4.

Methods: Participants were allocated into two groups. The rPMS group received 6,000 pulses of magnetic stimulation of the knee joint at a frequency of 20 Hertz for one session, and the sham group received a sham stimulation for one session. All the participants received conventional treatment. The result was measured by VAS and the Thai version of the modified Western Ontario and McMaster Universities Arthritis Index (WOMAC) score.

Results: The KL 2, 3, and 4 grades of the 30 participants, average age 62.83 years (SD 6.38), were 16, 11, and 3, respectively. The median (Q1, Q3) decrement of VAS between baseline and imme­diately after treatment and between baseline and one week after treatment of the rPMS group were 47 (38, 59) and 21 (9, 46). The median (Q1, Q3) decrement of VAS between baseline and immediately after treatment and between baseline and one week after treatment of the sham group were 41 (29, 50) and 17 (3, 30). The median (Q1, Q3) decrement of modified WOMAC between baseline and one week after treatment of rPMS and sham group were 25 (7, 53) and 2 (1, 15). The study found improvement of VAS and modified WOMAC in both groups, but the change in VAS was not statistically significant while modified WOMAC in the rPMS group showed statistically significant.

Conclusions: rPMS provides no significant additional thera­peutic effect in a short-term improvement of pain in primary knee osteoarthritis patients compared with sham treatment.