Ultrasound physiotherapy. Female patient having ultrasound physiotherapy applied to her knee, following an injury. The physiotherapist directs the ultrasonic beam to the site of pain (upper left). The use of high-frequency sound waves to treat soft-tissue injuries is thought to work by improving blood flow. Ligaments, muscles and tendons may feel warm and tingle during therapy. This type of treatment is thought to provide a better rate of healing as compared to traditional, manipulative, physiotherapy or pain killing drugs.