Acupuncture for Lateral Epicondylitis: A Systematic Review

Lateral epicondylitis, commonly known as tennis elbow, is a painful condition that affects 1% to 3% of the general population, primarily people between 45-54 years of age. This condition causes significant pain and loss of function of the affected limb, substantially impacting patients' social and professional lives. Activities involving overuse and repetitive use of the forearm extensor muscles, such as typing, tennis, and manual work, can cause this condition. This systematic review was conducted to assess the efficacy and safety of acupuncture for the treatment of lateral epicondylitis, focusing specifically on improvement in elbow function and muscle strength.

The researchers performed a comprehensive search of seven electronic databases and the WHO clinical trials search portal, from inception to 2015. Only randomized clinical trials comparing acupuncture (including electroacupuncture, manual acupuncture, and warm acupuncture) with controls such as sham acupuncture, placebo, no treatment, or active treatment were included. Primary outcomes were the functional status of the elbow, and secondary outcomes included muscle strength (myodynamic) and adverse events.

Four studies were included in the final analysis, totaling 309 participants aged 18 to 70 years and with lateral epicondylitis duration ranging from one month to 15 months. Two studies were conducted in China and two in Germany. Two trials compared acupuncture with sham acupuncture, one compared electroacupuncture combined with moxibustion with material insulation versus block therapy, and another compared electroacupuncture plus block therapy versus block therapy alone.

The results showed that acupuncture was superior to sham acupuncture for both improvement in elbow function (standardized mean difference -0.56, 95% CI -0.98 to -0.15, p = 0.008) and muscle strength (standardized mean difference 0.44, 95% CI 0.03 to 0.85, p = 0.04). The study comparing electroacupuncture combined with moxibustion versus block therapy also showed significant superiority of acupuncture (mean difference 12.10, 95% CI 10.65 to 13.55). However, when electroacupuncture was combined with block therapy and compared with block therapy alone, there was no statistically significant difference.

Regarding adverse events, three studies reported on safety. One study observed no serious adverse events, while two studies reported that needle pain was the primary reason for treatment discontinuation. The most commonly used acupuncture points included local points such as Large Intestine 4, 10, and 11, Small Intestine 5, and Ashi points located near the lateral epicondyle.

The methodological quality of the included studies was assessed as low using the Cochrane risk of bias tool. Main limitations included inadequate random sequence generation, lack of allocation concealment, and absence of adequate blinding of participants and personnel. The quality of evidence, assessed by the GRADE system, was classified as very low to low, primarily due to the small number of studies, small sample size, and methodological limitations.

In terms of clinical implications, although the results suggest that acupuncture may be beneficial for improving elbow function and muscle strength in patients with lateral epicondylitis, several important limitations must be considered. The small number of included studies and participants limits the reliability of pooled results. In addition, none of the trials reported formal sample size calculation, which is essential to ensure adequate statistical power. Variability in assessment scales may also have introduced bias, even with the use of standardized mean differences.

In conclusion, although this systematic review suggests that acupuncture may have some benefits for lateral epicondylitis, no definitive conclusion can be established due to the small number of included studies, limited methodological quality, and small sample sizes. Larger prospective trials with rigorous methodological design are needed to confirm the efficacy of acupuncture for this condition, as well as international standardization of assessment scales and outcome criteria.