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Research Review By Dr. Joshua Plener©


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Date Posted:

July 2022

Study Title:

Extracorporeal Shockwave Therapy for Mid‑portion and Insertional Achilles Tendinopathy: A Systematic Review of Randomized Controlled Trials


Paantjens M, Helmhourt P, Backx F, et al.

Author's Affiliations:

Sports Medicine Centre, Training Medicine and Training Physiology, Royal Netherlands Army, Utrecht, The Netherlands; Center of Excellence, Training Medicine and Training Physiology, Royal Netherlands Army, Utrecht, The Netherlands; Department of Rehabilitation, Physical Therapy Science and Sports, University Medical Center Utrecht, Utrecht, The Netherlands

Publication Information:

Sports Medicine – Open 2022; 8: 68.

Background Information:

Chronic Achilles tendinopathy is characterized by pain, swelling and decreased performance and is divided into mid-portion and insertional classifications, with mid-portion being more common (1, 2). Achilles tendinopathy occurs most frequently between the ages of 40-59, especially in athletes, runners in particular (3, 4).

For Achilles tendinopathy, the standard of care consists of mechanical loading protocols, with recent studies concluding that different loading programs provide similar results, regardless of the type of movement (5-7). In loading programs, pain and function typically improve after 2 weeks, with results peaking at 12 weeks. However, at 5-year follow-up, about half of patients seek alternative treatment due to not responding adequately (8).

Extracorporeal shockwave therapy is thought to influence the pathophysiological process and decrease pain and improve function in Achilles tendinopathy (4, 9). Shockwave therapy is considered to be safe and effective when combined with other treatments, but there is conflicting evidence.

No systematic reviews have included only experimental studies to review the effectiveness of shockwave therapy for mid- and insertional-Achilles tendinopathy separately. As a result, the aim of this systematic review is to synthesize the evidence from randomized controlled trials to determine the clinical effectiveness of shockwave therapy, either as a monotherapy or part of a multimodal package of care for chronic mid- and insertional-Achilles tendinopathy.

Pertinent Results:

Seven trials were included in this review, with three RCTs assessing mid-portion Achilles tendinopathy and four RCTs investigating insertional-Achilles tendinopathy. All three studies assessing mid-portion Achilles tendinopathy and three of the four studies assessing insertional Achilles tendinopathy were rated as low risk of bias, with the fourth study rated as high risk of bias.

Mid-Portion Achilles Tendinopathy:
A meta-analysis was conducted which showed that extracorporeal shockwave therapy in addition to standard care compared to standard care alone (classified as conservative care where at least tendon loading exercises or load management was included) produced a pooled VISA-A score of 10.28 points in favour of the shockwave group. One study compared shockwave therapy in isolation to standard care and did not produce statistically significant results.

Insertional Achilles Tendinopathy:
A meta-analysis was conducted which showed that extracorporeal shockwave therapy in addition to standard care compared to standard care alone (classified as conservative care where at least tendon loading exercises or load management was included) produced a pooled VISA-A score that favoured the standard care group with a standardized mean difference of -0.29. Furthermore, one study assessed shockwave therapy in isolation compared to standard care, which demonstrated a positive effect for the shockwave therapy group, with a standardized mean difference of 1.36.

In summary, there is moderate quality evidence to support the effectiveness of shockwave therapy for mid-portion Achilles tendinopathy and very low-quality evidence that shockwave therapy has no additional value over standard care for insertional-Achilles tendinopathy.

Clinical Application & Conclusions:

This is the first meta-analysis that synthesized the evidence on mid-portion and insertional Achilles tendinopathy (separately) from RCTs only. For mid-portion Achilles tendinopathy, shockwave therapy in addition to standard care was found to have superior effects compared to standard care in isolation. On the VISA-A questionnaire, the results demonstrated clinically important improvements. This finding agrees with previous studies and clinical practice guidelines (4, 10-12). The evidence for insertional-Achilles tendinopathy was more conflicting, with very low-quality evidence that shockwave has no added value compared to standard care. Future trials are needed to support this review’s findings.

The results of this review for insertional-Achilles tendinopathy are not supported by two other recently published systematic reviews (13, 14), which indicated that adding shockwave therapy to eccentric loading improves outcomes. However, these reviews included lower quality evidence such as retrospective and prospective cohort studies, case series, case control studies and pilot studies, which likely contributes to the difference in outcomes. The mechanism of action due to shockwave therapy remains unknown (15), and therefore it is difficult to fully explain the reasons behind shockwave therapy being more effective for mid-portion Achilles tendinopathy compared to insertional Achilles tendinopathy.

Study Methods:

Medline, Embase, and Cochrane were searched from inception to January 21, 2021.

Extracorporeal shockwave therapy was assessed in randomized and non-randomized controlled trials. Participants were 18 years of age and older with a clinical or radiologically-confirmed diagnosis of either mid- or insertional-Achilles tendinopathy, with symptoms for at least 3 months. Studies assessing the clinical effectiveness in mixed cohort studies of mid and insertional Achilles tendinopathy were excluded if results were not presented separately for both conditions. Furthermore, studies were included if they used either focused extracorporeal shockwave therapy and/or radial extracorporeal shockwave therapy, as both treatments are used commonly to treat tendinopathies.

The studies included compared shockwave therapy to different surgical and conservative interventions such as tendon loading programs, surgical procedures, and injections.

The studies used validated and reliable outcome measures to assess the clinical effectiveness of functional improvements, pain reduction and self-perceived recovery through questionnaires such as the VISA-A questionnaire, numeric rating scale (NRS) for pain or visual analogue scale (VAS) for pain, and global perceived effect. The minimal clinically important difference (MCID) for the VISA-A questionnaire was 6.5 points, and the MCID for the numeric rating scale was a 15% reduction of pain.

Risk of bias was assessed using the RoB 2 tool which assesses risk of bias in 5 domains: bias arising from the randomization process, bias due to deviations from the intended interventions, bias due to missing outcome data, bias in measurement of the outcomes, and bias in selection of the reported results. The quality of evidence was evaluated through GRADE by assessing risk of bias, inconsistency of results, indirectness of evidence, imprecision, and publication bias.

Study Strengths / Weaknesses:

  • This is the first study to assess the evidence on mid-portion and insertional Achilles tendinopathy separately in a meta-analysis from RCTs only.
  • The authors used rigorous methodology throughout this review.
  • The pooled estimates are likely not generalizable to individuals unwilling or unable to perform tendon loading programs – a component of all comparison ‘standard care’ groups in the included studies.
  • The results exclude individuals suffering from both mid-portion and insertional Achilles tendinopathy at the same time.

Additional References:

  1. Maffulli N, Khan KM, Puddu G. Overuse tendon conditions: time to change a confusing terminology. Arthroscopy 1998; 14(8): 840–3.
  2. Jarvinen TA, Kannus P, Maffulli N, et al. Achilles tendon disorders: etiology and epidemiology. Foot Ankle Clin 2005; 10(2): 255–66.
  3. Yasui Y, Tonogai I, Rosenbaum AJ, et al. The risk of Achilles tendon rupture in the patients with achilles tendinopathy:healthcare database analysis in the united states. Biomed Res Int 2017; 2017: 7021862
  4. Martin RL, Chimenti R, Cuddeford T, et al. Achilles pain, stiffness, and muscle power deficits: midportion achilles tendinopathy revision 2018. J Orthop Sports Phys Ther 2018; 48(5): A1–38.
  5. van der Vlist AC, Winters M, Weir A, et al. Which treatment is most effective for patients with Achilles tendinopathy? A living systematic review with network meta-analysis of 29 randomised controlled trials. Br J Sports Med 2021; 55(5): 249–56.
  6. Head J, Mallows A, Debenham J, et al. The efficacy of loading programmes for improving patient-reported outcomes in chronic midportion Achilles tendinopathy: a systematic review. Musculoskeletal Care 2019; 17(4): 283–99.
  7. Habets B. Rehabilitation of midportion achilles tendinopathy in athletes; Loading programmes, hip muscle function and return to sport (thesis). University Medical Centre, Utrecht/the Netherlands; 2021; ISBN 978-94-6416-867-9.
  8. van der Plas A, de Jonge S, de Vos RJ, et al. A 5-year follow-up study of Alfredson’s heel-drop exercise programme in chronic midportion Achilles tendinopathy. Br J Sports Med 2012; 46(3): 214–8.
  9. Irby A, Gutierrez J, Chamberlin C, et al. Clinical management of tendinopathy: a systematic review of systematic reviews evaluating the effectiveness of tendinopathy treatments. Scand J Med Sci Sports 2020; 30(10): 1810–26.
  10. Sussmilch-Leitch SP, Collins NJ, Bialocerkowski AE, et al. Physical therapies for Achilles tendinopathy: systematic review and meta-analysis. J Foot Ankle Res 2012; 5(1): 15.
  11. Rhim HC, Kim MS, Choi S, et al. Comparative efficacy and tolerability of nonsurgical therapies for the treatment of midportion Achilles tendinopathy: a systematic review with network meta-analysis. Orthop J Sports Med 2020; 8(7): 2325967120930567.
  12. de Vos RJ, van der Vlist AC, Zwerver J, et al. Dutch multidisciplinary guideline on Achilles tendinopathy. Br J Sports Med 2021; 55(20): 1125-1134.
  13. Zhi X, Liu X, Han J, et al. Nonoperative treatment of insertional Achilles tendinopathy: a systematic review. J Orthop Surg Res 2021; 16(1): 233.
  14. Jarin IJ, Backer HC, Vosseller JT. Functional outcomes of insertional achilles tendinopathy treatment: a systematic review. JBJS Rev 2021; 9(6): e20.
  15. Moya D, Ramon S, Schaden W, Wang CJ, Guiloff L, Cheng JH. The role of extracorporeal shockwave treatment in musculoskeletal disorders. J Bone Joint Surg Am 2018; 100(3): 251–63.

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