Effect of low-magnitude, variable-frequency vibration therapy on pain threshold levels and mobility in adults with moderate knee osteoarthritis—randomized controlled trial

BACKGROUND: Osteoarthritis (OA) is one of the most commonly recorded diseases in clinical practice. Vibration therapy has been suggested for the treatment of knee OA. The purpose of the study was to determine the impact of vibrations of variable frequency and low amplitude on pain perception and mobility in patients suffering from knee OA. METHODS: Thirty-two participants were allocated into two groups – Group 1 (oscillatory cycloidal vibrotherapy-OCV) and Group 2—control (sham therapy). The participants were diagnosed with moderate degenerative changes in the knee (grade II based on the Kellgren-Lawrence (KL) Grading Scale). Subjects received 15 sessions of vibration therapy and sham therapy respectively. Pain, range of motion, and functional disability were assessed through Visual Analog Scale (VAS), Laitinen questionnaire, goniometer (ROM – range of motion), timed up and go test (TUG) and Knee Injury and Osteoarthritis Outcome Score (KOOS). Measurements were taken at baseline, after the last session and four weeks after the last session (follow up). T-test and U-Mann Whitney test compare baseline characteristics. The Wilcoxon and ANOVA tests compared mean VAS, Laitinen, ROM, TUG and KOOS. The significant P-value was less than 0.05. RESULTS: After 3 weeks (15 sessions) of vibration therapy, reduced the sensation of pain and improved mobility was recorded. There was a more significant improvement in the vibration therapy group than the control group in pain alleviation on VAS scale (p < 0.001), on Laitinen scale (p < 0.001), knee ROMs flexions (p < 0.001) and TUG (p < 0.001) at the last session. KOOS score with pain indicator, symptoms, activities of daily living, function in sport and recreation and knee related quality of life improved more in the vibration therapy group than the control group. Effects maintained up to 4 weeks in vibration group. No adverse events were reported. CONCLUSIONS: Our data demonstrated that the use of vibrations of variable frequency and low amplitude in patients with the knee OA is a safe and effective therapy. It is recommended to increase the number of treatments performed, primarily in patients with degeneration II° according to the KL classification. TRIAL REGISTRATION: Prospectively registered on ANZCTR (ACTRN12619000832178). Registered on 11 June 2019.