Ultrasound therapy for knee pain

Updated April 17, 2017

Knee pain can be caused by a large number of factors that include the following; arthritis, tendinitis, bursitis, torn cartilage, torn ligament, strains or sprains, connective-tissues disorders (e.g., lupus) and knee injuries (dislocation of the kneecap). Ultrasound therapy is an approved physiotherapy treatment used by doctors, physical therapists and occupational therapists to help reduce and/or eliminate your knee pain by sending high frequency sound waves, which provide deep heat, to your affected knee tissues and stimulate the healing process.

Knee Joint Anatomy

Injuries to the knee joint are one of the most common of joint injuries, especially in sports. These injuries can persist for a long time if they are not treated properly. The knee joint is the largest joint in your body and consists of many ligaments, muscles and tendons. The knee contains four major bones: the femur (thigh bone), the patella (kneecap), the tibia (shin bone) and the fibula (outer shin bone). The four major ligaments, which provide knee stability, are the medial collateral ligament (MCL), lateral collateral ligament (LCL), anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). The two important muscle groups surrounding the knee joint are the quadriceps and the hamstrings.

Ultrasound Therapy

Ultrasound therapy treats acute and chronic knee pain using sound waves to transfer heat to your knee at frequencies between 0.8 to 3 megahertz. These waves can penetrate up to two inches deep. Your physical therapist will use a hand-held applicator (transducer) that receives electrical current from a console through a coaxial cable. The heat comes from the head of the applicator, and your physical therapist will move it continuously over your knee in small circular motions to avoid hot spots and burns. You will most likely feel a slight tingling of heat or no sensation at all. Treatment usually lasts 5 to 10 minutes each day and you will receive two to thee treatments a week for several weeks, depending upon your condition.

Two Ultrasound Therapy Approaches

Depending upon your condition, your physical therapist may use ultrasound in one of two ways, either a continuous wave or a pulsed-wave format. Continuous wave ultrasound therapy uses high-wave frequencies at a continuous transmission rate, which provides more heat and friction, thus increasing the metabolism of your tissue cells to heal faster. Pulsed-wave ultrasound therapy is recommended for acute inflammation and wound care where less heat is required. The pulsed waves are used to decrease inflammation and pain.


There are many benefits that you can receive from ultrasound therapy. These benefits include the following; stimulates the healing process, increases blood flow, reduces inflammation and swelling, improves circulation and metabolism of injured cells, helps to break down scar tissue, reduces irritation to nerve roots and reduces muscle spasms. Ultrasound therapy can also treat many types of knee pain caused from a wide variety of factors such as arthritis, musculoskeletal injuries and chronic conditions.


As with any medical treatment, ultrasound therapy does have some risks. First, you should not place the ultrasound device over any organs or other sensitive areas of your body, which include the following: heart, kidneys, liver, bowels, ovaries, testicles, spinal cord, brain, lung, eyes, ears and upper neck. Second, pregnant women should not use ultrasound on their abdomen or lower back region. Third, people with certain illnesses should not have ultrasound treatment, and these illnessesinclude haemophilia, spinal bifida, deep venous thrombosis and diabetic neuropathy. Lastly, people with pacemakers or other implants of any kind should not have ultrasound therapy.

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About the Author

Julie Powers lives in San Diego and has been writing professionally for eHow since 2009. She specializes in writing about business, real estate, health and pet topics. She works as an assistant to a real estate broker and applies her knowledge to her articles. She graduated from Indiana University's Kelley School of Business with a Bachelor of Science in management and entrepreneurship.