Therapeutic Ultrasound Overview
What is Therapeutic Ultrasound?
Therapeutic Ultrasound is a painless (typically the patient will feel nothing) modality used to treat injuries of all kinds. High-frequency sound waves are sent into the soft tissues to help decrease inflammation and expedite the healing process. Mechanical vibration at increasing frequencies is known as sound energy. The sound waves connect with tissues, alternating the state that they are in. A human audible sound range is from 16 Hz – 20,000 Hz, anything beyond this is considered ultrasound. In clinics, ultrasound machines range from 1 to 3 Mhz (1Mhz=1,000,000 Hz).
Due to the gentle nature and available settings of therapeutic ultrasound, the pulsed ultrasound setting can be used on an acute injury that is very sensitive and the continuous setting can be utilized on a chronic injury that is not very irritable.

Benefits of Therapeutic Ultrasound
Some benefits of therapeutic ultrasound include:
- Reduces swelling & inflammation
- Increases blood flow & elasticity
- Promotes tissue healing
- Decreases pain
This treatment is pain-free and does not require the use of anesthetics or pain relievers. It is simple and non-invasive, requiring no down time. Ultrasound waves naturally increase heat in tissues and the deep-heating effect aids in pain relief.
Which Conditions Benefit from this Treatment?
Therapeutic ultrasound is very versatile and can be used for many different soft-tissue injuries including (but not limited to):
- Ankle sprain
- Tendonitis
- Bursitis
- Arthritis
- Back pain
- Knee pain
- Tennis elbow, golfers elbow
- Shoulder pain, frozen shoulder, rotator cuff etc.
Contraindications Include:
Pregnancy – Pregnant women are recommended not to undergo ultrasound therapy, as overheating of the fetus could result.
PaceMakers – Patients with pacemakers are at risk due to the possibility that the sound waves might alter the implant’s performance. In these instances, the chest area must be avoided. As metal conducts heat, which could damage surrounding tissue, ultrasound is contraindicated in regions where metallic implants exist.
Blood Clots – Ultrasound therapy is also prohibited in patients known to have a tendency toward abnormal blood clot development. Warming and improving blood flow could encourage a hidden clot to travel through the bloodstream, which could lead to a heart attack, pulmonary embolism or stroke.
Eyes & Head – Ultrasound therapy can never be used over the eyes. A lack of sufficient blood circulation combined with the heat generated by the sound waves could lead to damaged retinas or an increased risk of developing cataracts. Avoiding the entire head is the rule of thumb.
How does Therapeutic Ultrasound differ from Diagnostic Ultrasound?
An imaging ultrasound, also known as a “diagnostic ultrasound” is the procedure of using sound waves to create images. This is done by sending in high-frequency sound waves into the body and looking at the waves that are bouncing back. These diagnostic ultrasounds are normally done in a hospital setting or medical imaging lab. Sonograms (the image produced by the ultrasound examination) are then presented to show what is going on the inside of people.
Therapeutic ultrasound is what we use at our clinic, and unlike diagnostic ultrasound, it does not have a receiver that catches the sound waves that are bouncing back to take visual images, it does however use sound waves for the treatment of soft-tissue injuries.
Frozen Shoulder
Frozen shoulder (also known as Adhesive Capsulitis) is a condition involving pain and stiffness in the ball and socket joint of the shoulder. Unfortunately, frozen shoulder can last a long time, and goes through different stages in the healing process.
Stages of Frozen Shoulder:
- Freezing stage: Any movement of the shoulder causes pain, and the shoulder’s ability to move becomes limited. This stage lasts from 2 to 9 months.
- Frozen stage: Pain might lessen during this stage. However, the shoulder becomes stiffer. Using it becomes more difficult. This stage lasts from 4 to 12 months.
- Thawing stage: The shoulder’s ability to move begins to improve. This stage lasts from 5 to 24 months.
What Causes Frozen Shoulder?
The shoulder is enclosed in a capsule of connective tissue. Frozen shoulder happens when this capsule thickens and tightens around the shoulder joint, causing a restriction in movement. Frozen shoulder typically happens to people ages 40 to 50 years old. It also happens to females more so than male in general. This is a condition in which we do not always know why it happens. It can sometimes occur after a traumatic injury, but an injury is not a requirement.
Therapeutic ultrasound may help by gently massaging underlying connective tissue, and softening it without adding extra strain on the patient. It is one of the potential treatments that may be recommended for this condition. It can also be done before exercises because it helps to increase the range of motion and improve the ability of your shoulder to stretch.

Getting Started
What to expect on your first treatment?
Therapeutic ultrasound utilizes a soundhead to deliver the sound waves directly into the tissues. First, your physiotherapist will administer a small amount of gel to the area that is being treated, to help with connectivity and ease of movement. Ultrasound does not conduct through the air, so the gel is needed for the complete conduction of the ultrasound waves throughout the whole treatment.
Depending on your injury (acute or chronic) your physiotherapist will choose either a continuous setting or pulsed setting, and the ultrasound head will be moved around in circular motions for a certain amount of time. While receiving this treatment, you will most likely not feel anything happening besides a slight warming sensation.
How many treatments are typically required?
Effectiveness of ultrasound therapy should be looked at in how you are feeling after each session, not in the number of times you have received it. As with any type of treatment, If you do not notice any changes after 3 – 4 treatments, your therapist should re-evaluate or select a different type of treatment. Ultrasound therapy can also be used in conjunction with other modalities. It will also vary depending if your injury is acute or chronic.