TENS for Knee Pain

08/18/2020 • Shai Gozani M.D., Ph.D.

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About one-quarter of adults suffer from frequent knee pain, which limits their mobility, disrupts their sleep and decreases their quality of life.  Chronic knee pain is usually treated with anti-inflammatory drugs such as ibuprofen, and sometimes with prescription opioids.  However, these medications may not be effective and often have side effects.  Opioids are particularly worrisome because of their addiction potential.  Knee replacement surgery, called total knee arthroplasty, is an option for some patients, however it is expensive and has a long recovery time.  There is an urgent need for drug- free and non-surgical treatments for chronic knee pain.

Transcutaneous Electrical Nerve Stimulation

Transcutaneous electrical nerve stimulation (TENS) is a safe, non-invasive treatment for chronic pain.  TENS devices generate an electric current that is passed through two, and sometimes more, electrodes that are placed in the vicinity of the pain.  The strength of the electric current, called intensity, is increased until a strong, non-painful sensation is felt around the electrodes.  The medical term for this sensation is paresthesia.  A decrease in pain is usually experienced within 10-20 minutes.  It is recommended that each treatment session last 30-60 minutes.  Pain relief occurs during stimulation and for a short time afterwards, and so treatment should be repeated multiple times a day (and even overnight) to help manage pain.

How effective is TENS for chronic knee pain?

As for most pain relief approaches, the answer is complicated.  There have been many, in fact hundreds, of clinical studies of TENS for knee pain, both for acute pain following knee surgery and for chronic pain.   Many studies suggested that TENS was effective in reducing knee pain, however some were unable to show that TENS actually reduced knee pain.  This situation is not unexpected for studies evaluating pain treatments because of the complexity of pain.  Experts in the TENS field, such as Professors Mark Johnson of Leeds Beckett University in the UK and Kathleen Sluka of the University of Iowa, believe that the inconclusive results are primarily due to poorly designed studies that used TENS sub-optimally. A common error in many studies, and also one made by people using TENS at home, is an inadequate stimulation intensity. It is crucial that TENS feel strong, otherwise an insufficient number of nerve fibers have been activated. Stimulation that is barely felt will not produce pain relief.  The required intensity will vary from person to person.  Another common problem is using TENS sporadically, such as 20-30 minutes a few times a week, and yet expecting substantial improvement in pain that is nearly constant.  TENS provides transient pain relief and needs to be used regularly to improve pain.  One should be skeptical of claims that a single brief TENS treatment will provide prolonged pain relief.

On balance it appears that TENS is effective for knee pain.  As for any pain treatment, it will not work for everyone and the amount of pain relief will vary.  You can increase your chances of getting meaningful pain relief by using as strong an intensity as comfortable and using your TENS device regularly when you are experiencing pain.

Will it work for me?

Knee pain is complicated.  In some people it is primarily caused by irritation of pain fibers around the knee, such as by inflammation.  In others, it may be due to hypersensitivity resulting from changes in the way pain is processed in the spinal cord and brain, called central sensitization.  Moreover, people react differently to similar pain because of their genetic, physiological and psychological make-up.  So, while it is true that TENS can be effective in knee pain, it is not possible to predict who will benefit and how much.  This is really no different than any other pain treatment.  The good news is that TENS is completely safe and so you can explore whether it helps you manage your pain and improve your quality of life.

Quell® for Knee Pain

Quell is a wearable pain relief device designed specifically for knee pain.  It is prescription strength and the most advanced TENS device available, and best of all you can get it quickly without a prescription.

About The Author
Shai Gozani M.D., Ph.D.

Dr. Gozani is an expert in non-invasive neurostimulation. He received his M.D. degree from Harvard Medical School and the Harvard-MIT Division of Health Science and Technology. Dr. Gozani earned his Ph.D. in Neurobiology, M.S. in Electrical Engineering & Computer Science and B.A. in Computer Science from the University of California at Berkeley. Following his studies, Dr. Gozani conducted post-doctoral research at Harvard Medical School and MIT. He holds 36 U.S. patents and has authored over 30 articles in scientific and clinical peer-reviewed journals. Dr. Gozani is founder, president and CEO of NeuroMetrix, Inc.; which designs and manufactures Quell.

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