The dose effectiveness of extracorporeal shockwave on plantar flexor spasticity of ankle in stroke patients: a randomized controlled trial

Abstract Background Extracorporeal shockwave therapy (ESWT) has been proven beneficial for post-stroke spasticity (PSS) of ankle plantar flexor muscles. This study aims to investigate the dose-response effectiveness of focused-ESWT and the duration of its effect on the treatment of ankle PSS in stroke patients. Methods In this double-blinded randomized controlled trial, stroke patients diagnosed with PSS in the ankle plantar flexor muscles were randomly assigned to two groups. The experimental group received double-dose ESWT (4000 pulses per session) targeting spastic calf muscles, while the control group received half the dose (2000 pulses per session). Both groups underwent four sessions over two weeks. The outcomes, including modified Ashworth Scale (MAS), modified Tardieu Scale (MTS), passive range of motion (PROM) of the ankle, Timed Up and Go (TUG) Test, Barthel index and strain elastography were evaluated at baseline, 1st, 4th, 12th, and 24th week after ESWT. Results Within-group analysis revealed significant improvements in MAS, PROM, TUG Test, and Barthel index for the double-dose ESWT group and improvements in Barthel index for the control group. Between-group analysis revealed greater improvements in TUG Test, Barthel Index and strain elastography for the double-dose ESWT group. Generalized estimating equations analysis indicated that the double-dose ESWT group achieved superior outcomes in the TUG Test, Barthel Index, and strain elastography across various time points and groups. Conclusions Double-dose ESWT showed better functional improvement and elastography compared to the control group. ESWT demonstrated dose-response effectiveness for PSS of ankle-equinus. Trial registration NCT05878223.