High Versus Low-Energy Extracorporeal Shockwave Therapy for Chronic Lateral Epicondylitis: A Retrospective Study.

Background: Chronic lateral epicondylitis (LE), also known as tennis elbow, affects 1-3% of the population, primarily those over 40 years old. Most cases resolve with conservative treatments, but some require more advanced interventions. Extracorporeal shockwave therapy (ESWT) has emerged as a non-surgical treatment option, utilizing either low- or high-energy levels to alleviate pain and improve function. Objective: This study aimed to compare the efficacy of low-energy versus high-energy ESWT in the treatment of chronic LE, focusing on pain relief and functional improvement. Methods: A retrospective observational study was conducted including patients treated for chronic LE between 2021 and 2024. Participants were divided into two groups: low-energy ESWT (0.10 mJ/mm²) and high-energy ESWT (0.20 mJ/mm²). Both groups received 2400 pulses at a frequency of 6 Hz once a week for three weeks. Pain and functional outcomes were measured using a visual analog scale (VAS) and the Patient-Rated Tennis Elbow Evaluation Questionnaire (PRTEE) at the baseline, three months (T1), and six months (T2) post-treatment. Results: Forty-six patients participated, with 24 in the low-energy group and 22 in the high-energy group. Baseline demographics and clinical characteristics were similar across groups. At T1 and T2, the low-energy group showed significantly greater reductions in the VAS scores (T1: 4.45 ± 0.8 vs. 3.6 ± 1.7, p = 0.04; T2: 3.2 ± 1.2 vs. 2.1 ± 1.1, p = 0.004) and PRTEE scores (T1: 34.3 ± 6.9 vs. 26.8 ± 11.9, p = 0.03; T2: 25.3 ± 6 vs. 17.6 ± 9, p = 0.005). Significant treatment-time interactions were observed for both the VAS and PRTEE scores, indicating sustained improvements in the low-energy group. Conclusions: Low-energy ESWT was more effective than high-energy ESWT in treating chronic LE, providing greater and longer-lasting pain relief and functional improvement. These findings suggest that low-energy ESWT should be preferred in clinical practice for managing this condition. Future research should focus on larger sample sizes and randomized controlled trials to confirm these results and explore the underlying mechanisms of differential efficacy between energy levels.