A recent report from the BMJ investigated whether adding a TENS unit to usual primary care – advice, exercises, NSAIDS – improved the 6-week outcome of pain intensity. (Cortisone injections were discouraged for purposes of the study.) The cohort consisted of 241 newly diagnosed cases of tennis elbow (lateral epicondylitis), half of whom received an additional TENS treatment once daily for 45 minutes. Pain scores were based on a 0-10 rating scale and the differences in scores between baseline and six weeks were evaluated.

At the end of six weeks both groups had large improvements in pain, but there was no clinically or statistically significant difference in adjusted pain scores between the groups. Notably, adherence to the regimens was poor in both groups with only 42 of the TENS group meeting the a priori definition of adherent. Analysis based upon those who were adherent to TENS use regardless of other interventions also failed to show any benefit of TENS use.

Tennis elbow is a common complaint affecting 1-3% of the population, with most in the 35-55 year age group. It is referred to as lateral epicondylitis, although the name inferring inflammation may be a misnomer as the inflammatory (vs degenerative) nature of the condition is debatable. The condition is commonly due to repetitive motions such as forearm rotation, strong gripping, or the handling of heavy loads. Perhaps of clinical importance is that the condition is usually self-limiting, although up to 20% report symptoms of greater than 12 months and recurrence is common.

TENS units are generally thought to work through stimulation of afferent nerves activating spinal gating mechanisms. They are not known to have any specific anti-inflammatory effects. This trial of TENS unit therapy suffers from poor adherence, but this alone may be cause to avoid TENS use in this condition. Although the study included randomized-to-treatment arms, it was not placebo controlled.

This new study showing a lack of effectiveness in prescribing TENS units is added to a previous blog post (http://phcprimarycare.org/?p=334) on a paper which concluded that injected corticosteroids are also of no benefit for tennis elbow. Physiotherapy has been shown to have better long-term outcomes, but keep in mind that tennis elbow is commonly both self-limited and recurrent.

Marshall Kubota, MD

Chesterton LS, BMJ 2013;347:f5160