Does therapeutic ultrasound work for knee arthritis?

What it is

Therapeutic ultrasound uses sound waves from a handheld probe pressed on the skin with a gel. It is given by physiotherapists and is meant to warm and soothe the tissues. It is not the same as the ultrasound scan used for imaging.

What the research shows

A Cochrane review found five small trials with 341 people who had knee arthritis. None included people with hip arthritis. Pain was lower with ultrasound than with a sham treatment or no treatment, by about 1.2 points on a 10 point scale. The range of likely values was 0.6 to 1.9 points. About 37 in 100 people with ultrasound had a good response, compared with 31 in 100 without it. Any gain in physical function could have been due to chance.

An earlier version of the review had found no benefit. The newer, small trials changed the picture, and the reviewers called for larger, well designed trials. A Harvard review of sham-controlled trials found that about two thirds of the pain relief from machine treatments such as ultrasound is also felt by people given a switched-off machine. The Australian GP guideline, the American College of Rheumatology and the international OARSI guideline all advise against ultrasound for knee arthritis.

Risks and effort

Ultrasound treatment is gentle and painless. The trials were too small to tell us much about rare problems.

What usually works instead

Exercise and strength work for the leg muscles have the best evidence. See Does exercise work for knee arthritis? and Osteoarthritis of the Knee.

Questions people ask

Is a change of 1.2 points worth noticing?

It is on the edge. A small gain like this may not change daily life much, and the trials were small enough that the true gain could be smaller.

Does it work for the hip?

No trial in the review included people with hip arthritis.

Is it the same as the ultrasound used for shoulder or heel pain?

This page covers knee arthritis. Other conditions have their own evidence.

Sources

Select a source to read what the study or guideline found, in plain words, with a link to the original.

• 1Cochrane review of therapeutic ultrasound, 2010Review
• 2Harvard review of placebo effects in knee arthritis treatments, 2020Review
• 3RACGP guideline for knee and hip osteoarthritis, 2018Australian guideline
• 4American College of Rheumatology guideline, 2020US guideline
• 5OARSI guideline for knee and hip osteoarthritis, 2019International guideline

Last reviewed 24 October 2026. Next review due October 2027.