Power Doppler Ultrasound Findings before and after Focused Extracorporeal Shock Wave Therapy for Achilles Tendinopathy: A Pilot Study on Pain Reduction and Neovascularization Effect

Abstract

Extracorporeal shock wave therapy (ESWT) has been found to have a positive effect in the treatment of pain in Achilles tendinopathy, although the exact mechanism is not yet completely understood. Among the mechanisms suggested to underlie ESWT effects are direct stimulation of healing, neovascularization and direct suppressive effects on nociceptors and hyperstimulation, which would block the gate-control system. The neovascularization observed in flogistic tissue is associated with stimulated nerve fibers around tendons and induces a painful condition. The objectives of the present study were to evaluate the effect of ESWT on pain and function in patients with non-insertional Achilles tendinopathy (NIAT) and to assess the neovascularization phenomenon using power Doppler ultrasound (PDU). Twelve patients with NIAT underwent five sessions of focused ESWT over 5 wk. Outcome measures were the visual analogue scale, the Victorian Institute of Sport Assessment–Achilles questionnaire and active dorsiflexion and plantar flexion ankle articular range of motion. Moreover, the patients’ clinical impressions of treatment results after ESWT were investigated using the Roles and Maudsley score. Patients were assessed at baseline and 1 and 3 mo after treatment. They had a significant reduction in pain with improvement of arthrokinematic motion and functionality and a positive clinical impression of treatment outcome (50% of patients considered their clinical picture as good/excellent after 3 mo). However, the pulse Doppler ultrasound exam did not reveal neovascularization in 91.7% of the patients 1 and 2 mo after focused ESWT, and in some patients there was a reduction in blood vessels related to flogistic processes. The present observational study confirmed the efficacy of ESWT in pain reduction in NIAT, with a higher degree of patient satisfaction, although doubt persists over the neovascularization effect on the Achilles tendons treated.