Submitted:
12 January 2025
Posted:
13 January 2025
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Abstract
Radial extracorporeal shock wave therapy (rESWT) is an established modality in the management of Achilles tendinopathy. A recent study published in Clinical Rehabilitation reported that the addition of rESWT to exercise and education did not lead to improvements in pain, function or other outcomes compared to the addition of sham rESWT at 6 or 12 weeks post-baseline in individuals with insertional Achilles tendinopathy. The authors concluded that any benefits of rESWT in the management of insertional Achilles tendinopathy may be explained by a placebo mechanism. We respectfully suggest that this conclusion, though likely justified in the light of the results obtained, is to be restricted to rESWT performed in this study, but should not be generalized to all rESWT: the energy of the radial extracorporeal shock waves applied in this study is not high enough to result in a positive clinical outcome.
Keywords:
insertional Achilles tendinopathy
; radial extracorporeal shock wave therapy
; rESWT
Radial extracorporeal shock wave therapy (rESWT) is an established modality in the management of Achilles tendinopathy [1,2,3,4,5,6]. A recent study published in Clinical Rehabilitation questioned the value of rESWT in the management of insertional Achilles tendinopathy [7]. Specifically, Alsulaimani et al. [7] reported no significant difference in the mean VISA-A score at 12 weeks post-baseline (W12) between patients who were randomly allocated to either rESWT and a specific exercise program (n=38; baseline: 44.8 ± 15.1 (mean ± standard deviation); W12: 66.4 ± 15.2; Δ = +21.6) or to sham rESWT and the same exercise program (n=38; baseline: 49.4 ± 15.1; W12: 64.6 ± 15.2; Δ = +15.2), respectively [7]. These data contradict a previous study on rESWT for insertional Achilles tendinopathy [2], which was not cited by Alsulaimani et al. [7] In that investigation [2], the mean VISA-A score of patients who were randomly allocated to rESWT (n=25) improved from 53.2 ± 5.8 at baseline to 79.4 ± 10.4 at four months post-baseline (M4; Δ = +26.2), and, in patients who were allocated to eccentric loading (n=25), from 52.7 ± 8.4 to 63.4 ± 12.0 at M4 (Δ = +10.7) [2]. Furthermore, in another previous study [3] on rESWT for midbody Achilles tendinopathy (again not cited by Alsulaimani et al. [7]), the mean VISA-A score of patients who were randomly allocated to a combination of rESWT and eccentric loading (n=34) improved from 50.2 ± 11.1 at baseline to 86.5 ± 16.0 at M4 (Δ = +36.3), and, in patients who were allocated to eccentric loading alone (n=34), from 50.6 ± 10.3 to 73.0 ± 19.0 at M4 (Δ = +22.4) [9].
Collectively, these data do not support the conclusion by Alsulaimani et al. [7] that any benefits of rESWT in the management of insertional Achilles tendinopathy may be explained by a placebo mechanism. Rather, these findings raise the legitimate hypothesis that the radial shock waves (rESWs) applied by Alsulaimani et al. [7] did not have enough energy to produce a significant therapeutic effect.
The rESWT device used by Alsulaimani et al. [7] was an Intellect RPW2 (Chattanooga, USA); 3000 rESWs per treatment session were generated by an air pressure between 2 and 5 bar at a frequency of 10 Hz. To our knowledge, no study has demonstrated the energy flux density (EFD) [8,9,10] generated by this rESWT device. However, without specifying the EFD, no statement can be made about the effectiveness of the rESWs applied by Alsulaimani et al. [7], because there is no direct relationship between the air pressure at which a pneumatic rESWT device is operated and the EFD of the generated rESWs [9,10]. Furthermore, different rESWT devices can generate rESWs with similar EFD at frequency of 1 Hz, but with substantially different EFD when operated at 10 Hz or at even higher frequencies [10].
The treatment success of rESWT primarily depends on the EFD of the applied rESWs, rather than on the cumulated EFD applied during a treatment session [11,12,13]. In this respect, rESWs are no different from focused extracorporeal shock waves [14], which are also effective in the management of Achilles tendinopathy [5,6,15]. Thus, the EFD of the rESWs applied by Rompe et al. [2] in the management of insertional Achilles tendinopathy (3 treatment sessions; 2000 rESWs per session; Swiss DolorClast (Electro Medical Systems, Nyon, Switzerland); 2.5 bar) was sufficient for this indication, whereas the rESWs applied by Alsulaimani et al. [7] likely were not.
In summary, we suggest that the conclusions that (i) the addition of rESWT to exercise and education did not lead to improvements in pain, function or other outcomes compared to sham at 6 or 12 weeks post-baseline in patients with insertional Achilles tendinopathy, and (ii) any benefits of rESWT in the management of insertional Achilles tendinopathy may be explained by a placebo mechanism, have to be restricted to the specific rESWT device used by Alsulaimani et al. [7], but not to rESWT in general. While the study [7] was performed well, the EFD of the rESWs was simply not high enough to produce a positive clinical outcome.
References
- Rompe, J.D.; Nafe, B.; Furia, J.P.; Maffulli, N. Eccentric Loading, Shock-Wave Treatment, or a Wait- and-See Policy for Tendinopathy of the Main Body of Tendo Achillis: A randomized controlled trial Am. J. Sports Med. 2007, 35, 374–383. [Google Scholar] [CrossRef] [PubMed]
- Rompe, J.D.; Furia, J.; Maffulli, N. Eccentric loading compared with shock wave treatment for chronic insertional achilles tendinopathy. A randomized, controlled trial. J. Bone Jt. Surg. 2008, 90, 52–61. [Google Scholar] [CrossRef]
- Rompe, J.D.; Furia, J.; Maffulli, N. Eccentric Loading versus Eccentric Loading plus Shock-Wave Treatment for Midportion Achilles tendinopathy: a randomized controlled trial. Am. J. Sports Med. 2008, 37, 463–470. [Google Scholar] [CrossRef]
- Yan, B.; Wan, Y.; Zhang, H.; Pan, M.; Zhou, C. Extracorporeal Shockwave Therapy for Patients with Chronic Achilles Tendinopathy in Long or Short Course. BioMed Res. Int. 2020, 2020, 7525096. [Google Scholar] [CrossRef] [PubMed]
- Al-Abbad, H.; Simon, J.V. The Effectiveness of Extracorporeal Shock Wave Therapy on Chronic Achilles tendinopathy: a systematic review. Foot Ankle Int. 2013, 34, 33–41. [Google Scholar] [CrossRef]
- Schmitz, C.; Császár, N.B.M.; Milz, S.; Schieker, M.; Maffulli, N.; Rompe, J.-D.; Furia, J.P. Efficacy and safety of extracorporeal shock wave therapy for orthopedic conditions: a systematic review on studies listed in the PEDro database. Br. Med Bull. 2015, 116, 115–138. [Google Scholar] [CrossRef] [PubMed]
- Alsulaimani, B.; Perraton, L.; Vallance, P.; Powers, T.; Malliaras, P. Does shockwave therapy lead to better pain and function than sham over 12 weeks in people with insertional Achilles tendinopathy? A randomised controlled trial. Clin. Rehabilitation Epub ahead of print. 2024. [Google Scholar] [CrossRef] [PubMed]
- Cleveland, R.O.; Chitnis, P.V.; McClure, S.R. Acoustic Field of a Ballistic Shock Wave Therapy Device. Ultrasound Med. Biol. 2007, 33, 1327–1335. [Google Scholar] [CrossRef] [PubMed]
- Császár, N.B.M.; Angstman, N.B.; Milz, S.; Sprecher, C.M.; Kobel, P.; Farhat, M.; Furia, J.P.; Schmitz, C. Radial Shock Wave Devices Generate Cavitation. PLOS ONE 2015, 10, e0140541. [Google Scholar] [CrossRef] [PubMed]
- Reinhardt, N.; Wegenaer, J.; de la Fuente, M. Influence of the pulse repetition rate on the acoustic output of ballistic pressure wave devices. Sci. Rep. 2022, 12, 1–7. [Google Scholar] [CrossRef]
- Chow, I.H.W.; Cheing, G.L. Comparison of different energy densities of extracorporeal shock wave therapy (ESWT) for the management of chronic heel pain. Clin. Rehabilitation 2007, 21, 131–141. [Google Scholar] [CrossRef]
- Kenmoku, T.; Iwakura, N.; Ochiai, N.; Saisu, T.; Ohtori, S.; Takahashi, K.; Nakazawa, T.; Fukuda, M.; Takaso, M. Influence of different energy patterns on efficacy of radial shock wave therapy. J. Orthop. Sci. 2020, 26, 698–703. [Google Scholar] [CrossRef]
- Zhang, Y.; Liu, Y.; Chou, S.; Weng, H. Dose-related effects of radial extracorporeal shock wave therapy for knee osteoarthritis: A randomized controlled trial. J. Rehabilitation Med. 2021, 53, jrm00144. [Google Scholar] [CrossRef] [PubMed]
- Gerdesmeyer, L.; Wagenpfeil, S.; Haake, M.; Maier, M.; Loew, M.; Wörtler, K.; Lampe, R.; Seil, R.; Handle, G.; Gassel, S.; et al. Extracorporeal Shock Wave Therapy for the Treatment of Chronic Calcifying Tendonitis of the Rotator cuff: a randomized controlled trial. JAMA 2003, 290, 2573–2580. [Google Scholar] [CrossRef] [PubMed]
- Gatz, M.; Schweda, S.; Betsch, M.; Dirrichs, T.; de la Fuente, M.; Reinhardt, N.; Quack, V. Line- and Point-Focused Extracorporeal Shock Wave Therapy for Achilles Tendinopathy: A Placebo-Controlled RCT Study. Sports Heal. A Multidiscip. Approach 2021, 13, 511–518. [Google Scholar] [CrossRef] [PubMed]
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