The Leeds University team said good nursing and the occasional laugh was a better way to get the body healing than using the latest technology.
Hospitals and health clinics are increasingly using low-dose ultrasound for leg ulcers.
But the five-year study of 337 patients found it did nothing to speed up recovery, the British Medical Journal reported.
Instead, lead researcher Professor Andrea Nelson said: “They key to care with this group of patients is to stimulate blood flow back up the legs to the heart. The best way to do that is with compression bandages and support stocking coupled with advice on diet and exercise.
“Believe it or not, having a really hearty chuckle can help too. This is because laughing gets the diaphragm moving and this plays a vital part in moving blood around the body.”
During the study, the team concentrated on patients with hard-to-heal ulcers that had not cleared up after six months or longer.
They found that adding ultrasound to the standard approach to care – dressings and compression therapy – made no difference to the speed of healing or the chance of ulcers coming back.