Thirteen consecutive patients underwent plantar fasciotomy in 16 feet for intractable plantar fasciitis and had follow-up from 4.5 to 15 years. Plantar fasciotomy was successful (good or excellent results) for 71% of the 14 feet operated on and for which follow-up data were available. However, time to full recovery was prolonged, additional treatment was frequently required, and abnormalities of foot function persisted. Flattening of the longitudinal arch occurred. Dynamic force-plate studies showed differences in peak vertical, fore-aft, and lateral-medial forces between patients and matched controls. More rapid progression of weightbearing along the longitudinal axis of the foot during stance phase in patients indicated avoidance of heel loading.