Transcutaneous electrical nerve stimulation (TENS) involves putting electrical currents into the tissues of the body. It may sound like a torture device. But it is actually used to treat pain. Doctors don't know exactly how it works. It is thought to create a sensation that overrides the pain sensation in the brain.

These researchers tested TENS in patients who had a total knee replacement (TKR). TKR can be a very painful surgery. But medicine such as morphine shouldn't be heavily used in TKR patients. Too much morphine after surgery can cause other problems, such as nausea, vomiting, constipation, and reduced lung function.

For this study, TKR patients were divided into three groups. For the first 24 hours after surgery, one group got the standard self-controlled doses of pain medicine. The second group got standard pain medicine plus TENS. The third group got pain medicine and false TENS treatments. (The wires were placed into the bandages rather than onto the body.)

The researchers tried to compare the amount of pain reported by the patients. However, patients slept through much of the 24 hours and so didn't give many pain reports. The researchers also looked at the amount of pain medicine each group needed. They found that all groups needed about the same amount of pain medicine. TENS seemed to offer no real pain relief at all. This study does not support the idea that TENS can be useful for acute pain after TKR.

Reference:

Robert Breit, MBBS, FRACS, FAOrthA, and Hans Van der Wall, MBBS, PhD, FRACP. Transcutaneous Electrical Nerve Stimulation for Postoperative Pain Relief after Total Knee Arthroplasty. In The Journal of Arthroplasty. January 2004. Vol. 19. No. 1. Pp. 45-48.'