Dose-Related Effect of Extracorporeal Shock Wave Therapy for Plantar Fasciitis

OBJECTIVE To examine the dose-related effect of extracorporeal shock wave therapy (ESWT) for plantar fasciitis. METHODS Sixty patients with plantar fasciitis despite conservative treatment were enrolled. The patients were divided into a low-energy group (group L: n=30, 1,000 shocks/session, energy flux density [EFD] per shock 0.08 mJ/mm(2)) and a medium-energy group (group M: n=30, 1,000 shocks/session, EFD 0.16 mJ/mm(2)). The main outcome measures were visual analogue scale (VAS), Roles and Maudsley (RM) score, and thickness of plantar fascia (PF). To compare the effects between each group, follow-up was carried out 1 week after 3 and 6 sessions, and 1 and 3 months after ESWT. RESULTS Significant VAS and RM score improvement, and PF thickness reduction were observed in both groups (p<0.01). After 3 sessions of ESWT, group M showed significant improvement in the VAS and RM score than group L, whereas after 3 additional sessions applied in group L, the main outcomes were no longer significantly different in both groups (p>0.05). CONCLUSION Therapeutic effect might disclose a dose-related relationship; therefore, EFD and the times of the session are considerable factors when treating with ESWT.