Comparison of treatment effects on lateral epicondylitis between acupuncture and extracorporeal shockwave therapy

Lateral epicondylitis, popularly known as tennis elbow, is a repetitive strain injury that affects between 1-3% of the general population and up to 23% of workers with specific occupational activities. This condition is characterized by pain and tenderness at the lateral epicondyle of the humerus, significantly affecting function and activities of daily living. Despite its high prevalence, there is still no established standard treatment for this condition. In Hong Kong, both acupuncture and extracorporeal shockwave therapy (ESWT) have gained popularity in the treatment of lateral epicondylitis, but few studies have directly compared the efficacy of these methods.

This pioneering study was developed to compare the therapeutic effects of acupuncture and ESWT in the treatment of lateral epicondylitis. Using a parallel-group study design, 34 patients with confirmed diagnoses were randomized into two groups of 17 participants each. The acupuncture group received treatment twice a week for three weeks, totaling six 20-minute sessions. The protocol included six specific points: Ah-shi (local pain point), LI-10 (Shousanli), LI-11 (Quchi), LU-5 (Chize), LI-4 (Hegu), and TE-5 (Waiguan), with insertion depth of 1.25-2.5 cm and induction of De Qi sensation every five minutes.

The ESWT group received three weekly sessions for three weeks, using a focused shockwave generator at a frequency of 2000 Hz and energy flux density ranging between 0.032-0.822 mJ/mm², applied at the origin of the common extensor tendon.

Assessments were performed at three time points: before treatment (baseline), immediately after the end of treatment, and two weeks after the end of the intervention. Primary outcomes included pain intensity measured by the Visual Analog Scale (VAS), maximum grip strength assessed with the Jamar dynamometer, and level of functional impairment measured by the DASH (Disabilities of the Arm, Shoulder, and Hand) questionnaire.

The results demonstrated no statistically significant difference between the two treatments at any time point. Both groups showed significant improvement in pain scores in longitudinal comparisons. In the acupuncture group, pain decreased from 6.12 to 3.88 points on the VAS after treatment, representing a reduction of approximately 37%. In the ESWT group, the reduction was from 5.47 to 3.65 points, corresponding to a decrease of about 33%.

Importantly, this improvement remained significant at the two-week follow-up in both groups, with effect sizes considered large (>0.8) for both interventions.

Regarding grip strength and function as measured by the DASH questionnaire, although a trend toward improvement was observed in both groups, no statistically significant differences were found. This finding suggests that, although both treatments are effective for pain relief, longer periods or modified protocols may be needed to observe substantial functional improvements.

An interesting aspect observed was that the improvement in pain ceased when treatment ended in both groups, suggesting that the analgesic effect is directly related to the period of active intervention. However, pain relief persisted for at least two weeks after the end of treatment, indicating a beneficial residual effect.

In terms of safety, 17.6% of patients in the acupuncture group reported local pain after treatment, while 29.4% of patients in the ESWT group complained of pain during or after sessions. These findings suggest a slightly better tolerability profile for acupuncture.

This study represents the first direct comparison between acupuncture and ESWT for lateral epicondylitis with adequate sample size, providing important evidence to guide clinical practice. The results suggest that both modalities are viable therapeutic options, with similar short-term efficacy in pain relief, allowing professionals and patients to make informed choices based on personal preferences, availability, and cost-effectiveness considerations.