Most children develop arches in their feet by early adolescence. About 20 percent, however, have pes planovalgus (PPV), also known as flexible flatfoot. Until recently in the U.S., children have had two options at extreme ends of the treatment spectrum: conservative treatment or complex foot reconstruction with multiple osteotomies. A third option that bridges the gap between conservative treatment and foot reconstruction is practiced widely in several European countries—and has been for decades. Subtalar extra-articular screw arthroereisis (SESA), also known as calcaneo-stop, is a minimally invasive procedure to correct symptomatic flexible flatfoot without complex foot reconstruction. During a SESA procedure,...