Red Light Therapy for Tennis Elbow: Scientific Evidence

A tennis elbow brace embedded with 4 infrared light-emitting diodes (LEDs) at 940 nm was designed and tested in a single patient in a 2019 observational study from the University of Social Welfare and Rehabilitation Sciences in Tehran, Iran. A 35-year-old woman wore the custom brace 5 cm below the outer elbow during daily activities over 42 days, with each of the 4 LEDs delivering 500 mW of optical output, combining to 2 W total, at a distance of 1.97 inches. It was reported that pain decreased from 7 to 3 on a pain scale, with grip strength, pinch strength, and arm function all improving over the 6-week period.

Improvements in pain, grip strength, and quality of life continued to increase through 6 months after treatment in a 2016 observational study of high-intensity laser therapy (HILT) for tennis elbow at Konya Education and Research Hospital in Turkey. 30 patients (22 women, 8 men, mean age 47) received 10 HILT sessions over 14 days using 1064 nm laser in 2 phases at the elbow, with phase 1 lasting 75 seconds and phase 2 lasting 12.5 minutes, at power outputs of 4, 8, and 12 W, fluence of 6 to 120 J/cm2 per phase (overall range 100 to 150 J/cm2), energies of 150 to 3000 J per phase, and a pulse frequency of 25 Hz in phase 1. The study reported significant improvements in activity and resting pain, arm function, grip strength, and quality of life both immediately after treatment and at 6 months. Researchers described HILT as a safe and effective treatment modality throughout the study period.

93 patients with tennis elbow were divided into 3 groups in a 2015 prospective randomized controlled trial from Afyon Kocatepe University in Turkey, testing high-intensity laser therapy (HILT) against sham therapy and an elbow brace. The HILT group of 30 received 1064 nm pulsed Nd:YAG laser at 10.5 W and 10 to 40 Hz, delivering a fluence of 0.36 to 1.78 J/cm2 and total energy of 1275 J per session over 15 minutes at a clinician-controlled distance, applied to the outer elbow, extensor tendon, and forearm over 15 days. Researchers reported significant improvements in pain, grip strength, and disability in both the HILT and brace groups at 4 and 12 weeks, with no significant difference between these 2 groups and no improvement in the sham group. No adverse events were observed in any of the 3 groups during the study.

Pain on finger extension was reduced by up to 100% at 12 months in the laser group of a 2013 randomized placebo-controlled double-blinded trial from Selkirk College in Canada, testing class IV laser therapy for chronic tennis elbow. 16 subjects were assigned to a laser group or a sham group and received 8 treatments over 18 days of dual-wavelength 810 and 980 nm class IV laser at 10 W, 22 mW/cm2, and 6.6 J/cm2 for 5 minutes per session, targeted at the forearm extensor tendon. Researchers reported that handgrip strength, function, and pain all showed significantly greater improvements in the laser group compared with sham at 3, 6, and 12 months, with the sham group showing minimal change until 12 months. No adverse effects were reported at any time during the study.

Studies published between 1990 and 2009 were systematically reviewed and meta-analyzed in a 2010 publication from Da Chien General Hospital in Taiwan to evaluate low-level laser therapy (LLLT) for tennis elbow. The 10 included randomized controlled trials covered 351 patients and used wavelengths of 632.8 to 1060 nm at power outputs of 0.07 to 90 mW, pulse frequencies of 50 to 5000 Hz, and an irradiance of 100 mW/cm2. Sessions lasted 20 seconds to 8 minutes, were given 7 to 12 times per week, used a fluence of 0.5 to 21 J/cm2 and energy doses of 0.004 to 5.4 J, and were applied to tender points, trigger points, or acupuncture points. Greater pain relief and improvements in grip strength and range of motion were observed when LLLT was applied to tender and trigger points than when applied to acupuncture points.

A 2008 systematic review with meta-analysis from Bergen University College in Norway evaluated low-level laser therapy (LLLT) for tennis elbow, pooling data from 13 randomized placebo-controlled trials and 730 patients. Studies examined wavelengths of 632 to 1064 nm at power outputs of 5 to 50 mW, and an irradiance of 100 mW/cm2, with energy doses of 0.5 to 7.2 J applied at distances of near contact to 3.937 inches over therapy durations of 21 to 56 days. The review reported that 904 nm and 632 nm wavelengths applied directly to the outer elbow tendon were associated with short-term pain relief and reduced disability, while trials targeting acupuncture points or using 820, 830, and 1064 nm wavelengths found no benefit. No serious side effects were reported across the included trials.

3 treatments for tennis elbow were compared in a 2008 randomized controlled trial at Ankara Education and Research Hospital in Turkey, with grip strength improving only in the laser group. 58 patients (9 men, 49 women) were divided into a brace plus exercise group (20), an ultrasound plus exercise group (18), and a low-level laser therapy (LLLT) plus exercise group (20), with the LLLT group receiving 633 nm laser at 10 mW to the outer elbow for 10 minutes per session over 14 days, with follow up assessed at 70 days. Pain improved in all 3 groups at 2 weeks, with the laser and ultrasound groups maintaining improvement at 6 weeks while pain returned in the brace group. All patients in all 3 groups tolerated their treatment well, with no adverse effects reported.

50 patients with tennis elbow took part in a 2007 randomized controlled trial from Peloponnese University in Greece, comparing low-level laser therapy (LLLT) combined with plyometric exercises against placebo laser with the same exercises. The active group of 25 received 904 nm Ga-As continuous wave laser at 40 mW and 50 Hz to the outer elbow at a fluence of 2.4 J/cm2 for 30 seconds per session. 12 sessions were given over 56 days, at 2 per week for the first 4 weeks and 1 per week for the final 4 weeks. At 8-week follow-up, significantly greater reductions in pain and improvements in grip strength and range of motion in the laser group at the end of treatment were reported.

Pressure pain sensitivity, grip strength, and pain ratings all showed significantly greater improvements with low-level laser therapy (LLLT) than with sham laser treatment in a 2007 randomized controlled trial for tennis elbow at Queen Elizabeth Hospital in Hong Kong, though 2 physical function measures showed no significant difference. 39 patients were randomly assigned to an active laser group or a sham group and received 904 nm, 25 mW laser at 5000 Hz to the outer elbow, at 0.28 to 0.66 J per tender point, an irradiance of 2 to 100 mW/cm2, and a fluence of 2.4 J/cm2, combined with exercise. Each tender point was treated for 11 seconds across 9 total sessions over 21 days.

Researchers at 2 laser centers in Switzerland and Croatia compared 3 low level laser therapy (LLLT) techniques for tennis elbow and golfer's elbow in a 1998 multicenter double-blind randomized controlled trial. 324 patients (274 with tennis elbow, 50 with golfer's elbow) were divided into a trigger point group, a scanner group, and a combination group. Sessions lasted 19 to 32 seconds, were delivered at distances of contact to 1.97 inches, used wavelengths of 632.8 nm, 830 nm, and 904 nm at power outputs of 10 to 120 mW, delivered energies of 2.5 to 60 J at a fluence of 12 J/cm2, and were given 6 to 24 times per week. Researchers found the combination group achieved total pain relief in 82% of acute cases and 66% of chronic cases.

In 1997, a single-blind clinical trial found that combining low-power laser therapy with steroid injection produced greater pain relief for tennis elbow than either treatment used alone. 32 patients were divided into 3 groups, with 11 receiving 904 nm low-power laser therapy (LPLT) applied to the elbow at 5000 Hz and 1 J/cm2, 11 receiving steroid injection alone, and 10 receiving combined steroid injection and LPLT. It was reported that the combined group showed a significantly greater pain-relieving effect at 7 days after treatment onset.

A 1992 randomized controlled trial compared low-level laser therapy (LLLT) with a placebo laser for tennis elbow. Researchers treated 30 patients, randomly assigning 15 to a laser group and 15 to a placebo group, applying 904 nm light from an 18 mW laser to the outer elbow at a fluence of 3.5 joules per square centimeter for 10 minutes per session across 8 days. The study reported that the laser group showed greater improvement in pain ratings and grip strength than the placebo group at the 4 week follow up, though researchers cautioned that LLLT alone may have limited value for treating tennis elbow.

49 patients with tennis elbow took part in a 1991 randomized controlled trial that tested low energy laser therapy against a placebo laser. Researchers randomly assigned participants to a laser group or a placebo group and applied 904 nm light to the outer elbow, delivering a dose of 0.36 J per point from a 12 mW laser, with treatment given 2 to 3 times weekly for a total of 10 treatments over 10 days. At the end of the study, laser was associated with significant improvement in some objective measures after treatment and at the 3-month follow-up, though no significant difference was found between groups in patient-reported subjective outcomes. No side effects were reported during or after treatment.

A private practice team in Indianapolis conducted a 2023 umbrella review pooling 35 systematic reviews and meta-analyses on nonoperative tennis elbow treatments, with low-level laser therapy included among several approaches examined. The review covered 310 participants and noted that laser protocols used wavelengths of 904 and 632 nm applied to the outer elbow. Researchers found exercise therapy reduced pain regardless of dosage or type, steroid injections provided the most short-term relief, and platelet-rich plasma and blood-derived injections were most effective long term. Conflicting results were reported for laser, ultrasound, and shockwave therapy, with the reviewers cautioning that variation in study quality and populations makes the evidence uncertain.

Control groups in tennis elbow trials achieved 50 to 66% of the gains seen in treatment groups, according to a 2015 meta-analysis from TU Darmstadt in Germany examining low-level laser therapy (LLLT) and other physical therapies. 16 randomized controlled trials were included from searches of PubMed, EMBASE, and the Cochrane database, with 904 nm laser applied to the outer elbow in sessions given 0.25 to 5 times per week over therapy durations of 21 to 90 days. Out of all, only treatment groups combining therapy-specific and non-therapy-specific factors reliably met criteria for clinical relevance, with LLLT associated with partial effectiveness for pain relief and grip strength in tennis elbow.

A 2011 observational study from Keele University in the United Kingdom reviewed management options for tennis elbow and found that while a wait-and-see approach is recommended as first-line care, low-level laser therapy (LLLT) may offer benefit in the medium term alongside physiotherapy. 730 participants were included across the reviewed studies, with LLLT applied at 904 nm at a contact distance to the outer elbow tendon at 100 mW/cm2, with energy doses of 0.25 to 1.2 J at power outputs of 5 to 50 mW. During evaluation, LLLT was associated with partial effectiveness, noting it may help reduce symptoms in the medium term but emphasizing that no clear consensus exists on the best long-term management of tennis elbow.

15 treatments for tennis elbow were systematically reviewed in a 2011 publication from the University of Queensland in Australia, with low-level laser therapy (LLLT) assessed alongside steroid injections, exercise, ultrasound, and other interventions across 80 studies. For LLLT specifically, data were drawn from 2 trials involving 1007 participants, with 904 nm laser applied in contact to the tendon area. Researchers reported that LLLT was associated with partial benefit for tennis elbow, suggesting some improvement in symptoms but not full resolution.

No short-term benefit over placebo was found for gallium-arsenide (GaAs) laser therapy in a 2010 randomized controlled trial for tennis elbow at Uludag University in Turkey, though significant functional improvements were observed in the laser group at 12 weeks. 49 patients (50 elbows) were divided into a laser group (25) and a placebo group (25), receiving 904 nm GaAs laser to the outer elbow at a fluence of 2.4 J/cm2 for 2 minutes per session, 5 times weekly for 21 days. The laser group reported significant improvements at 12 weeks in pain on wrist extension, tenderness, arm function scores, and pain-related quality of life. Researchers noted that GaAs laser therapy was associated with relatively no side effects.

A team at the Mayo Clinic in Rochester tested low-intensity Nd:YAG laser therapy for tennis elbow in a 2000 randomized controlled trial. 52 outpatient men and women aged 18 to 70 received 1060 nm continuous wave laser applied to 7 points along the forearm for 60 seconds per point at 204 mW/cm2 and a fluence of 12.24 J/cm2, 3 times weekly for 28 days. There were no statistically significant differences found between the treated and placebo groups in pain, tenderness, grip strength, pinch strength, or medication use, either during treatment or at follow-up. No significant treatment side effects were noted.

Compared with a placebo laser, Gallium Arsenide (GaAs) laser applied to acupuncture points produced no significant improvement for tennis elbow in a 1990 double-blind clinical trial. The 49 participants were treated at 5 acupuncture points on and around the outer elbow using 904 nm light at 12 mW and 70 Hz, with each point receiving 0.36 J over 30 seconds at a distance of 0.0394 inches, across a total of 10 treatments. Researchers found no significant differences between the laser and placebo groups in either subjective or objective outcomes after treatment or at the 3-month and 1-year follow-ups. No side effects were reported during or after the treatment period.