ESWT for tendinopathy: technology and clinical implications

Abstract

PurposeThe general consensus that tendinopathy, at least in the chronic stage, is mainly a degenerative condition and inflammation plays a minor role has led to a shift from treatments that target inflammation towards treatment options that promote regeneration. One of these treatments is extracorporeal shockwave therapy (ESWT), a physical therapy modality that uses pressure waves to treat tendinopathy. This review was undertaken to give an overview of the literature concerning this treatment, and special attention is given to the differences between focused and radial ESWT.MethodsA narrative description of wave characteristics, generation methods and in vitro effects of ESWT is given. The literature on ESWT as a treatment for one common tendinopathy, patellar tendinopathy, was systematically reviewed.ResultsWaves that are generated for focused and radial ESWT have very different physical characteristics. It is unclear how these characteristics are related to clinical effectiveness. Studies into the biological effects of ESWT have mainly used focused shockwave therapy, showing a number of effects of shockwaves on biological tissue. The systematic review of studies into the clinical effects of ESWT for patellar tendinopathy showed conflicting evidence for its effectiveness.ConclusionPhysical characteristics of focused and radial waves differ substantially, but effect on clinical effectiveness is unclear. Whereas in vitro studies often show the effects of ESWT on tendon tissue, results of clinical studies are inconsistent. Based on the review of the literature, suggestions are given for the use of ESWT in clinical practice regarding timing and treatment parameters.Level of evidenceIV.Electronic supplementary materialThe online version of this article (doi:10.1007/s00167-012-2009-3) contains supplementary material, which is available to authorized users.

Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function

“…Park et al25 confirm that ESWT can strengthen endothelial NO synthase activity, and the production of NO increases in cells. At the same time, the enhanced anti-inflammatory effect is also reflected in the decreased expression of NF-κB and its dependent gene 26. ESWT can also strengthen the expression of BMP-2 and transforming growth factor β,27,28 so applying low-energy ESWT for treatment after SCI has neuroprotective effect 29.…”

Ultrasound-guided intervention in the ankle and foot

“…The mechanism of action includes overstimulation of a painful area causing decreased pain signals to the brain stem, so called "hyperstimulation analgesia"; regeneration causing the tenocytes to produce more collagen; and breaking of tendon calcification. 40 Evidence shows only minor improvement in function, pain and alignment score. [40][41][42][43][44][45] The NICE has issued a statement on extracorporeal shockwave therapy in Achilles tendinopathy concluding that it is safe, but there is no consensus opinion regarding efficacy.…”

“…40 Evidence shows only minor improvement in function, pain and alignment score. [40][41][42][43][44][45] The NICE has issued a statement on extracorporeal shockwave therapy in Achilles tendinopathy concluding that it is safe, but there is no consensus opinion regarding efficacy. Therefore, they advise that this procedure should only be used with special arrangements for clinical governance, consent and audit or research.…”

Biological mechanism of shockwave in bone

“…Despite of clinical success, the working mechanism of ESWT in bone healing has not been fully established. The mechanism of ESWT is suggested through mechanotransduction to induce the reaction of the bone lacunae-canalicular network to tensile, shear and compression forces [7,8]. It was speculated that shockwave produced micro-fracture that in turn causes hematoma formation and subsequent callus formation and eventual fracture healing [9,10].…”