Effectiveness of Therapeutic Ultrasound on Clinical Parameters and Ultrasonographic Cartilage Thickness in Knee Osteoarthritis: A Double-Blind Trial

OBJECTIVE: A double-blind placebo-controlled randomized study was conducted to assess the effectiveness of therapeutic ultrasound (US) in knee OA. PATIENTS AND METHODS: Thirty-three patients (mean age 54.7 ± 14.7) were randomized to receive either continuous US (n = 15) or sham US (n = 18) as a placebo. Continuous ultrasonic waves with 1 MHZ frequency and 1 watt/cm(2) power were applied for 5 min for 10 sessions. The primary outcome was pain on movement assessed by visual analog scale (VAS). The secondary outcomes were WOMAC scores and measurements of distal femoral cartilage thickness by imaging US. RESULTS: Both groups showed reduced knee pain on movement following intervention. The VAS measurements improved significantly both in the treatment and the placebo group patients (P < 0.05 and P < 0.05). WOMAC scores improved statistically significant in all domains (pain, stiffness, physical function, and total score) in the treatment group (P < 0.05). All domains of WOMAC score showed statistically significant change when compared with the placebo group (P < 0.05). There was no change in the cartilage thickness measurements of medial femoral condyle, lateral femoral condyle, and intercondylar area in both groups after intervention. CONCLUSION: Results suggest that US is effective treatment modality in pain relief and improvement of function in patients with knee OA; however, US had no effect on cartilage repair.