NEW YORK (Reuters Health) -- Deep heat treatment can help relieve shoulder pain due to inflammation or tearing of rotator cuff tendon, a new study confirms.

There is currently no agreed-upon treatment for patients with inflammation or tears in the tendons that make up the rotator cuff of the shoulder, Dr. Nicola Maffulli of Keele University School of Medicine in Stoke on Trent, England and colleagues write.

Hyperthermia, in which the surface of the skin is kept cool while tissues deep in the affected area are heated with microwaves to about 110 degrees F, has recently been introduced as a physical therapy and rehabilitation technique, Maffulli and her team note in the August issue of the American Journal of Sports Medicine.

After having success with hyperthermia for treatment of tendon and muscle injuries in athletes, the researchers tested the approach in a pilot study of patients with a type of rotator cuff injury known as supraspinatus tendinopathy. The supraspinatus muscle is located on the top of the shoulder blade and is joined to the humerus bone at the top of the arm by a tendon.

They divided 37 athletes, all of whom had been experiencing shoulder pain for three to six months, into three groups. One received hyperthermia treatment three times a week for four weeks; the second group was given ultrasound therapy on the same schedule; and the third group performed five minutes of exercise twice daily for four weeks.

The researchers assessed the study participants' pain before treatment, immediately after treatment was completed, and six weeks after the end of treatment. Only patients in the hyperthermia group reported a significant reduction in pain after treatment and during follow-up. Four patients reported feeling some discomfort due to the high temperature, but treatment was not halted for this reason and the discomfort was temporary.