Abstract
Lateral epicondylitis (LE), also known as tennis elbow, is an overuse tendinopathy originating from the forearm extensor tendons of the elbow. An emerging therapy for the treatment of LE is the use of transdermal nitroglycerin (NTG) patches for pain relief and improved function. The aim of this systematic review was to assess the current literature on the effect of a transdermal NTG patch for the treatment of LE. A literature search using MEDLINE, EMBASE, SportDiscus, and the Cochrane Database of Systematic Reviews was conducted. Studies selected for inclusion were those in which patients were clinically diagnosed with LE, RCTs, observational studies, and only articles published in English. Studies were excluded if they involved patients <18 years of age or involved patients with a potential alternative source of elbow pain such as previous surgery to the elbow, a previous history of dislocation, fracture of the elbow or tendon rupture, or a referred pain source such as cervical radiculopathy or peripheral nerve involvement. Studies were also excluded if they involved patients who were already prescribed topical NTG for any other indication (i.e., angina), and if the studies had no measurement of symptom relief or measurement or functional scoring. The initial search strategy yielded 69 articles, out of which four met the eligibility criteria and were included in this systematic review. The studies showed improvement in elbow pain in the short-term and mid-term (up to six months), while one study that followed participants for a five-year duration post-treatment, showed no benefit. Three studies used an effective NTG dose of 1.25mg/24h and one study used an effective dose of 1.44mg/24h. Topical NTG was more effective when combined with a tendon rehabilitation program. The most commonly reported side effects of topical NTG were headaches and dermatitis. Overall, the current literature demonstrates that the use of NTG patches for LE improves short- and mid-term pain as well as elbow function. However, more studies are required to fully understand the effect of topical NTG on LE, particularly the effective dose range and the long-term benefits.