For chronic knee or shoulder pain, therapeutic ultrasound may have some benefit for some people for managing pain, but others may receive no benefit. Other treatments may be more effective for managing knee or shoulder pain. There isn’t any evidence about whether therapeutic ultrasound is helpful for chronic hip pain.
Researchers looked at patients with chronic hip, knee, and shoulder pain, and compared those who received therapeutic ultrasound to those who did not. They measured pain relief. They found that:
This was a systematic review. A systematic review summarises all available studies on a health care intervention to provide high quality evidence on the effectiveness of that health care intervention.
Who participated in the study? This review included 15 studies of patients receiving therapeutic ultrasound for chronic pain. Eight studies included 594 patients with chronic knee pain, and seven studies included 351 patients with chronic shoulder pain. No studies of patients with chronic hip pain were identified. Chronic pain was defined as lasting at least 3 months.
How was the study done? The reviewers included studies that compared therapeutic ultrasound as monotherapy (that is, without any other treatments) with either an active comparator (any other treatment) or sham ultrasound. The comparator could also be therapeutic ultrasound combined with another treatment. The types of ultrasound included were continuous low intensity and pulsed.
Active comparator or sham ultrasound
Therapeutic ultrasound uses sound waves that are out of the range of human hearing to relieve pain or disability. A round-headed probe with gel is usually applied directly to the skin of the affected area. The ultrasound can be continuous, which produces a thermal effect, or pulsed, which has interruptions for short periods of time and does not produce a thermal effect.
Many different comparators were used in these studies. Many studies used sham ultrasound, in which a probe is applied to the skin but no ultrasound waves are emitted.
Other active comparators included:
Continuous low-intensity ultrasound and pulsed ultrasound therapy are commonly used to treat joint pain. The focus of treatment for joint pain is to restore motion, reduce pain, and return to daily activities.
Therapeutic ultrasound is thought to work by providing deep heating to soft tissues in the body. This produces muscle relaxation and increases local blood flow, which may help the body heal and reduce pain and inflammation.
Therapeutic ultrasound also has non-thermal effects called “cavitation” which introduces energy into the body, speeds cellular processes, and improves healing. This may also lead to a reduction in pain.
In continuous low-intensity ultrasound, the ultrasound waves are emitted continuously which produces the thermal effect. In pulsed ultrasound, the waves have short interruptions, which still produces cavitation effects without the thermal effects.
Both continuous and pulsed ultrasound have been used for chronic pain conditions. The authors wanted to investigate whether therapeutic ultrasound, either continuous or pulsed, was effective in treating chronic joint pain.
This Evidence Summary is based on the following article:
Aiyer R, Noori SA, Chang KV, et al. Therapeutic Ultrasound for Chronic Pain Management in Joints: A Systematic Review. Pain Med. 2019 May 16. pii: 5490299. doi: 10.1093/pm/pnz102. PubMed
Published: Thursday, June 27, 2019