From the Guidelines
The primary purpose of ultrasound therapy is to treat pain, muscle spasms, and joint contractures by delivering high-frequency sound waves to the affected area, increasing tissue temperature, enhancing cellular activity, and reducing inflammation. The therapy comes in two forms: thermal ultrasound, which generates heat in tissues to increase blood flow and reduce pain, and mechanical ultrasound, which creates non-thermal effects through cavitation and acoustic streaming to reduce inflammation and promote healing 1. A typical treatment session lasts 5-10 minutes, with frequencies ranging from 1-3 MHz and intensities between 0.5-2.0 W/cm². For acute conditions, lower intensities and pulsed mode are recommended, while chronic conditions may benefit from continuous mode with higher intensities. The depth of penetration varies with frequency—1 MHz reaches deeper tissues (3-5 cm), while 3 MHz targets more superficial areas (1-2 cm) 1. Some key points to consider when using ultrasound therapy include:
- Contraindications: metal implants, pacemakers, growth plates in children, reproductive organs, eyes, and areas with malignancy, infection, or impaired sensation
- Treatment duration and frequency: 5-10 minutes, 1-3 MHz
- Intensity and mode: lower intensities and pulsed mode for acute conditions, higher intensities and continuous mode for chronic conditions
- Depth of penetration: 1 MHz for deeper tissues, 3 MHz for superficial areas It is essential to note that while ultrasound therapy can be beneficial, research on its efficacy shows mixed results for different conditions, and its use should be guided by clinical judgment and evidence-based recommendations 1.
From the Research
Purpose of Ultrasound Therapy
The purpose of ultrasound therapy is to treat musculoskeletal disorders, including:
- Acute soft tissue injuries
- Overuse syndromes
- Chronic orthopedic and rheumatologic conditions
- Tendinopathy As stated in the studies 2, 3, 4, therapeutic ultrasound (TUS) is used to promote soft tissue injury healing and control inflammation.
Conditions Treated with Ultrasound Therapy
Ultrasound therapy is used to treat various conditions, including:
- Musculoskeletal soft tissue pain
- Carpal tunnel syndrome
- Calcific tendinitis of the shoulder
- Lateral epicondylitis
- Shoulder pain
- Degenerative rheumatic disorders
- Ankle distortions
- Temporomandibular pain or myofacial pain As noted in the studies 2, 3, 5, the effectiveness of ultrasound therapy in treating these conditions is still questionable due to conflicting results.
Mechanism of Action
The mechanism of action of ultrasound therapy involves the use of noninvasive, atraumatic waves to induce bioeffects in tendon and promote healing 4. However, the mixed successes of ultrasound therapy may be attributed to the wide variety of achievable parameters and the lack of standardization in measurements and reporting 4.
Efficacy of Ultrasound Therapy
The efficacy of ultrasound therapy is still a topic of debate, with some studies suggesting that it is effective in treating certain conditions 2, 3, while others find little evidence to support its use 5, 6. As stated in the study 3, there is little evidence that active therapeutic ultrasound is more effective than placebo ultrasound for treating people with pain or a range of musculoskeletal injuries.