Etiology of Tennis Elbow
Lateral epicondylitis, also known as tennis elbow, results from repetitive gripping of the thumb and forefingers. Repetitive stress from racquet sports, hobbies or manual labor leads to inflammation and micro tears in the tendon. The condition commonly presents as pain on the outer portion of the elbow at the insertion of the extensor carpi radialis brevis.
Treating Lateral Epicondylitis
Traditional treatment options include eccentric strengthening protocols, watchful waiting, corticosteroid injections, and nonsteroidal anti-inflammatory drugs (NSAIDS). Unfortunately, these common treatments rarely offer lasting pain relief. Epicondylitis is a self-limiting condition that usually resolves over a 12-18 month period. Substantial evidence is lacking for traditional treatments, which leaves many patients suffering through an 18 month course of disease. For example, there is limited evidence to support the use of eccentric exercise over splinting, massage, or concentric exercise. Corticosteroid injections and NSAIDs offer short term pain relief, but do not resolve patients concerns in the long term. Watchful waiting, i.e. wait for symptoms to run their course, was shown as effective as physiotherapy and more effective than corticosteroids over a 52 week period.¹ Alternatively, the regenerative potential of laser therapy has been shown to decrease pain and increase functionality in recent studies.
Laser Therapy and Tennis Elbow
We looked at several studies evaluating the use of laser therapy to treat lateral and medial epicondylitis. While study design and dosage varied, outcomes consistently favored the treatment groups. A placebo controlled study involving 39 patients found favorable pain and functionality outcomes by administering .0275 J per tender point with a 904 nm wavelength laser over 9 sessions.² Another placebo controlled study involving 50 patients found statistically significant improvements in pain with resisted wrist extension, tenderness, and functionality scores after 15 sessions with a 905 nm wavelength laser.³ Favorable results were again observed in a large-scale placebo controlled study with 324 patients; total relief of pain was observed in 82% of patients with acute epicondylitis.⁴ And finally handgrip strength was improved and pain with extension decreased over 8 sessions with a Class IV laser.⁵
Cellular Response to Laser Therapy in Epicondylitis
Near infrared light penetrates tissues and interacts with the mitochondrial membrane where the electron transport chain unfolds. The fourth complex of the electron transport chain contains a known photoreceptor, cytochrome c oxidase (CcOX). CcOX regularly bonds to nitric oxide (NO), which slows adenosine triphosphate (ATP) production. When light interacts with CcOX, the bond with NO dissociates leading to vasodilation. Additional blood flow increases tissue repair via the migration of tendocytes which rebuild the extracellular matrix within the elbow. Thus the non-invasive application of near infrared light increases the body’s capacity to repair damaged tissues and has been shown to decrease pain while increasing functionality in patients with lateral and medial epicondylitis.
- Sims SEG, Miller K, Elfar JC, Hammert WC. Non-surgical treatment of lateral epicondylitis: a systematic review of randomized controlled trials. Hand (New York, NY). 2014;9(4):419-446.[ncbi]
- Liz Kit Yin Lam and Dr. Gladys Lai Ying Cheing. Effects of 904-nm low-level laser therapy in the management of lateral epicondylitis: a randomized controlled trial. Photomed Laser Surg. 2007;25(2):65-71.[liebertpub]
- Emanet SK, Altan LI, Yurtkuran M. Investigation of the effect of GaAs laser therapy on lateral epicondylitis. Photomed Laser Surg. 2010;28(3):397-403.[ncbi]
- Simunovic Z, Trobonjaca T, Trobonjaca Z. Treatment of medial and lateral epicondylitis–tennis and golfer’s elbow–with low level laser therapy: a multicenter double blind, placebo-controlled clinical study on 324 patients. J Clin Laser Med Surg. 1998;16(3):145-51.[ncbi]
- Roberts DB, Kruse RJ, Stoll SF. The effectiveness of therapeutic class IV (10 W) laser treatment for epicondylitis. Lasers Surg Med. 2013;45(5):311-7.[ncbi]