Effects of metformin phonophoresis and exercise therapy on pain, range of motion, and physical function in chronic knee osteoarthritis: randomized clinical trial.

Background: Knee osteoarthritis (KOA) is a common musculoskeletal disorder. Therapeutic ultrasound (US) is a safe and effective treatment for KOA. It relieves knee pain and enhances function. Metformin (MF) regulates chondrocytes, hence providing chondroprotection. Furthermore, it efficiently reduces knee articular cartilage degeneration and retards the progression of osteoarthritis. However, the localized administration of MF by phonophoresis for KOA has yet to be studied.

Purpose: To assess the possible effects of metformin phonophoresis (MFPH) plus exercise therapy (EX) compared to MFPH alone or the US on knee pain, function, and range of motion (ROM) in chronic KOA patients.

Methods: Seventy-eight patients with unilateral mild to moderate chronic KOA were included. Patients were randomly assigned to three groups: group A (MFPH + EX), group B (MFPH alone), and group C (US). The US group used an acoustic-neutral gel, while the MFPH group used a gel containing 1.2% MF. The exercises included hamstring stretches, calf stretches, and knee strengthening exercises. Treatment in the three groups continued for four weeks (three sessions per week). The Visual Analog Scale (VAS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the goniometer were used to assess knee pain, function disability, and ROM, respectively. All measures were recorded before, 2 weeks, and 4 weeks after the intervention in all groups. Multivariate Analysis of Variance (MNOVA) was performed to compare the effects within and between groups for knee ROM and function disability. The Kruskal-Wallis test and the Friedman test analyzed the pain intensity.

Results: When the baseline patient characteristics were compared, there were no significant differences in means of age, gender, body mass index (BMI), or lower limb dominance across the three groups (p > 0.05). After 4 weeks of intervention, clinical outcomes significantly improved in all three groups (p < 0.05). However, patients in the MFPH + EX group improved significantly in all outcomes compared to the MFPH and US groups (p < 0.05).

Conclusion: Post-treatment results showed a statistically and clinically significant improvement in pain intensity, knee ROM, and function in the MFPH group; however, combining MFPH with exercises is more beneficial in reducing KOA symptoms.

Trial Registration: Clinical Trial Registry at (pactr.samrc.ac.za) database. NO: PACTR202311507335269. Date: November 9, 2023 (retrospectively registered).