MODEL RELEASED. Ultrasound treatment of ligament injury. Physiotherapist using an ultrasound transducer (centre) to treat a patient's knee ligament injury. The injury is to the medial and lateral knee ligaments, on the inside and outside of the knee respectively. The transducer is here being held against the inside of the knee. There are four knee ligaments in total, all of which help to hold the joint together, joining the thigh bone and the lower leg bones. Ultrasound treatment (the use of high-frequency sound waves) can warm the injured area, increasing blood flow and speeding recovery from injury.