This study examined the effects of treatment with Phyllanthus amarus nanoparticle gel applied by phonophoresis (PP) and ultrasound therapy (UT) in patients with symptomatic knee osteoarthritis (OA) using a randomized, double-blind, controlled trial.

Patients with knee OA (n = 40; mean age ± SD, 64.30 ± 9.71 years), who had visual analogue scale (VAS) scores for knee pain intensity of 68.00 ± 9.58 (UT group) and 71.00 ± 8.74 (PP group, respectively) before treatment, were randomly allocated into two groups. Both groups were treated with an ultrasound program in continuous mode, 1.0 W/cm², 10 min per session, for 10 sessions. Nanoparticles of P. amaruswere used in the PP group, whereas a nondrug coupling gel was used in the UT group. The 6-min walk test (6-MWT) was performed to evaluate functional capacity. The VAS and the 6-MWT were evaluated before and after 10 treatment sessions in both groups using a double-blind procedure.

VAS and 6-MWT showed significant improvement after treatment in both groups (p < 0.05). The PP group showed more significant effects than the UT group, in terms of both reducing the VAS pain score (p < 0.05) and improving 6-MWT (p < 0.05).

PP is suggested as an effective method for the treatment of symptomatic knee OA for reducing pain and improving functional capacity.