Dose-related Effect of Radial Extracorporeal Shockwave Therapy (rESWT) on Lateral Epicondylitis in Active Patients: A Retrospective Comparative Study

Background: Extracorporeal shock wave therapy is a noninvasive, safe, and well-tolerated treatment method which is increasingly used in the treatment of lateral epicondylitis. However, the gold standard treatment protocol is still controversial. Objectives: This study aimed to investigate and compare the efficacy of two different pneumatic pressure levels of radial extracorporeal shockwave therapy (rESWT) in active patients with lateral epicondylitis, unresponsive to conservative treatment. Methods: This retrospective comparative study was carried out in the Department of Orthopedics and Traumatology, Duzce University School of Medicine in 2018. A total of 330 patients with lateral epicondylitis unresponsive to conservative treatment were underwent rESWT during years 2010 - 2017. The patients were divided into two groups of 181 patients (group 1) with a total of 1500 impulses of 10 Hz frequency at 1 bar of air pressure during five treatment sessions at 1 week intervals, and 149 patients (group 2) with a total of 2000 impulses of 10 Hz frequency at 2 bars of air pressure during five treatment sessions at 1 week intervals. Functional and clinical outcomes were assessed just before the treatment, at six weeks and six months after treatment using the visual analogue scale (VAS) and the Quick-Disabilities of the Arm, Shoulder, and Hand (Q-DASH) score. Results: The mean VAS score had significantly decreased in group 1 from 8.34 +/- 1.22 to 2.59 +/- 1.49 (P = 0.0001) and had also in group 2 from 8.56 +/- 1.22 to 2.56 +/- 1.76 (P = 0.0001). The mean Q-DASH score decreased significantly in both groups; from 58.92 +/- 18.48 to 9.27 +/- 5.85 (P = 0.0001), and from 65.36 +/- 19.32 to 9.25 +/- 6.28 (P = 0.0001) in group 1 and group 2, respectively. No significant difference was observed between the pretreatment VAS and the 6-month scores of groups 1 and 2 (P = 0.103). The mean difference in the Q-DASH pretreatment and 6-week scores and between the pretreatment and 6-month scores in group 2 were higher than those in group 1 (P = 0.011, P = 0.003). Conclusions: Although both rESWT treatment regimens caused a decrease in pain and loss of function, the superior treatment protocol for rESWT appears to be five treatment sessions at 1-week intervals, with 2000 impulses per session and 2 bars. rESWT is a good option for treating lateral epicondylitis, as it is safe and effective and leads to no complications.