Acute Effect of Topical Menthol on Chronic Pain in Slaughterhouse Workers with Carpal Tunnel Syndrome: Triple-Blind, Randomized Placebo-Controlled Trial $0.00

Acute Effect of Topical Menthol on Chronic Pain in Slaughterhouse Workers with Carpal Tunnel Syndrome: Triple-Blind, Randomized Placebo-Controlled Trial

By: Phil Page, PhD, PT, ATC, CSCS, FACSM | May 13, 2019
Wrist Pain

Summary

Carpal tunnel syndrome is a painful condition of the wrist and hand associated with repetitive movement and overuse. It affects as many as 3% of the population, and results from inflammation of the tendons and nerves in the wrist. While prevention through education and ergonomic changes are ideal, many who suffer from carpal tunnel syndrome seek treatment for their pain.

Conservative treatment often consists of medication, bracing, and physical or occupational therapy. Because of the potential side-effects of oral medication, topical pain relievers are sometimes used in musculoskeletal pain syndromes.

Biofreeze® topical analgesic has been shown in several published studies to relieve pain in patients with knee osteoarthritis, neck pain, and low back pain. It’s thought that Biofreeze acts through a cryotherapy mechanism, where menthol activates cold receptors to reduce pain. (Watch this video to learn more behind Biofreeze’s mechanism of action).

Researchers in Denmark at the National Research Center for the Working Environment in Copenhagen wanted to compare Biofreeze (containing menthol) to a placebo gel with a menthol scent, on slaughterhouse workers with chronic pain symptoms of carpal tunnel syndrome.

In their triple-blinded, randomized, placebo-controlled study (the highest level of research design), ten workers with symptoms of carpal tunnel syndrome received either Biofreeze or the placebo gel applied to their forearm. The researchers measured the subjects’ pain at 1, 2, and 3 hours following application.

Compared to the placebo group, the group receiving Biofreeze reduced hand/wrist pain by 31% (1.3 points on a 0-10 visual analog scale). The pain reduction lasted at least 3 hours after application. Interestingly, this pain reduction lasted longer than the perceived cooling effect. The researchers reported a ‘moderate’-sized treatment effect (0.63) of Biofreeze.

It’s important to note that while Biofreeze acutely decreased pain associated with carpal tunnel syndrome, the workload and repetitive nature of the occupation must be adjusted. Using Biofreeze to reduce the pain associated with carpal tunnel syndrome may also help facilitate therapeutic exercise or other interventions.

This is the first study to evaluate the effectiveness of Biofreeze on a neuropathic condition. The researchers suggest menthol may have an effect on neuropathic pain by inactivating sodium channels. In conclusion, they stated that Biofreeze “should be considered as an effective non-systemic alternative to regular analgesics in the workplace management of chronic localized musculoskeletal and neuropathic pain.”

Sundstrup, et al. Acute Effect of Topical Menthol on Chronic Pain in Slaughterhouse Workers with Carpal Tunnel Syndrome: Triple-Blind, Randomized Placebo-Controlled Trial. Rehabilitation Research and Practice, vol. 2014, Article ID 310913, 7 pages, 2014.

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