Does ultrasound therapy work to treat osteoarthritis of the knee?

Does ultrasound therapy work to treat osteoarthritis of the knee?
This Cochrane review looked at the studies done to date on ultrasound therapy. Three studies tested 294 people with osteoarthritis of the knee or hip. The studies compared people who were given either ultrasound therapy, fake therapy or another type of electric current therapy, such as short wave diathermy or galvanic current.

What are osteoarthritis and ultrasound therapy?Osteoarthritis (OA) is the most common form of arthritis that can affect the hands, hips, shoulders, knees and feet. The tissue (cartilage) that protects the ends of the bones breaks down and causes pain and swelling. Drug and non-drug therapies can relieve pain and/or swelling. Ultrasound is a non-drug therapy given by physical therapists that uses pressure waves or vibrations. There are two types of ultrasound waves: pulsed (on and off) and continuous (non-stop). The pulsed waves do not produce heat, but they may decrease swelling. The continuous waves, however, produce heat that can soothe inflamed joints. It is not clear whether ultrasound therapy can be used to reduce the symptoms of osteoarthritis.

How well does ultrasound therapy work?Based on these studies, our best guess is that the effect of having 12 sessions of ultrasound therapy over 4-6 weeks on pain, range of motion of the joints, or speed while walking is about the same as the effect of having fake therapy.
Two studies comparing ultrasound therapy to other types of electric current therapy show that the effect of ultrasound on pain, disease activity and function is about the same as the effect of the other types of electric current therapy. In this case, therapy was provided for either 1 session or 10 sessions over 3 weeks.

There is no evidence about whether ultrasound therapy works on the wrists or hands. Unfortunately, the studies do not say whether the ultrasound therapy is pulsed or continuous, which makes it hard to give conclusions about whether pulsed or continuous therapy is better.
How safe is ultrasound therapy?Side effects were not given in any of the studies.

What is the bottom line

There is “silver” level evidence that ultrasound therapy does not improve the symptoms of osteoarthritis of the hip or knee. The effect of ultrasound therapy on osteoarthritis of the wrists and hands is not known.
Better studies need to be done to determine if ultrasound should be used to treat osteoarthritis.
Based on Robinson VA, Brosseau L, Peterson J, Shea BJ, Tugwell P, Wells G. Therapeutic ultrasound for osteoarthritis of the knee. The Cochrane Database of Systematic Reviews, 2001, Issue 3.