Effect of Extracorporeal Shockwave Therapy on Passive Ankle Stiffness in Patients With Plantar Fasciopathy

Abstract

Plantar fasciopathy (PF) is the most common cause of heel pain. Extracorporeal shockwave therapy (ESWT) improves the gait pattern in patients with PF. However, the effects of ESWT on the biomechanics of the ankle in these patients remains unclear. Sixteen participants were included in the present study. Of the 16 participants, 8 patients with PF were assigned to receive extracorporeal shockwave therapy, and 8 healthy participants served as an external control group. ESWT was applied to the PF group for 1500 pulses at an energy flux of 0.26 mJ/mm2 every 3 weeks for 3 sessions. The biomechanics of the ankle joints were then assessed using an isokinetic dynamometer, and a health-related quality of life questionnaire was administered at baseline and at the final follow-up session 12 weeks after the initial treatment. Passive stiffness was calculated and compared between the foot affected with PF, the opposite foot, and both feet of those in the healthy control group. The Kruskal-Wallis 1-way analysis of variance with repeated measures was performed, and statistical significance was considered present at the 5% (p ≤ .05) level. Ankle dorsiflexion in the affected limb increased from 14° ± 3° to 17° ± 2° after ESWT (p < .05). No statistically significant differences were noted in the strength of dorsiflexion or plantarflexion at baseline and after ESWT. However, a statistically significant increase in the ratio of strength in ankle dorsiflexion versus plantarflexion was found after ESWT (p < .05). No differences in the passive stiffness of the ankle joint were demonstrated. Patients reported an improved physical function score after ESWT (p < .05). An increased dorsiflexion/plantarflexion torque ratio and maximal dorsiflexion associated with decreased pain might contribute to the improved physical function after ESWT for PF.