The aim of this study was to compare whether the effectiveness of continuous ultrasound (US) was superior against pulsed US and against sham US in knee osteoarthritis.
A randomized controlled study was carried out on 60 patients diagnosed with knee osteoarthritis according to American College of Rheumatology. The patients were randomized into the following three treatments: (1) continuous US (at a frequency of 1 MHz with intensity of 1 W/cm2), (2) pulse US (same frequency and intensity on 1:4 pulse ratio), and (3) sham US. All treatments were applied with 5-cm2 head US device five times a week for 2 weeks in addition to home exercise program including quadriceps isometric exercise, muscle strength exercises, and stretching exercises of the lower extremity muscles for at least three times per week. Assessments were performed at baseline, at the end of the treatment, and at the end of the treatments and at the sixth month using the following measurements: Western Ontario and McMaster University Osteoarthritis Index–pain, stiffness, function, visual analog scale–pain at rest, visual analog scale–pain on movement, visual analog scale–disease severity, and 20-m walking time. Among these parameters, the Western Ontario and McMaster University Osteoarthritis Index–pain was the primary outcome.
All groups showed a significant improvement in all parameters in both following visits (P < 0.05). However, there was no significant difference between the groups. Although the mean reduction percent in Western Ontario and McMaster University Osteoarthritis Index–pain was significantly higher in group I (continuous US) when compared to sham group (46.5% vs 28.9%, P < 0.05) at the end of the treatment, this result was not found in other pain parameters.
The present study demonstrated that all assessment parameters significantly improved in all groups without a significant difference. This result suggested that therapeutic US provided no additional benefit in improving pain and functions in addition to exercise training.