Fig. 1

Evaluation of foot posture and rearfoot angle. a Foot-scanning system to evaluate three-dimensional foot posture. b Measurement of calcaneus angle relative to the floor (θ1), which was defined as the angle formed by a line joining the bottom of the calcaneal tuberosity (a) with the enthesis of the Achilles tendon (b) and a line perpendicular to floor. c, Measurement of the hallux valgus angle (θ2). The hallux valgus angle (θ2) was defined as two lines intersecting between a line connecting the medial side of the first metatarsophalangeal joint (b) with the medial side of the heel (a) and a line connecting the medial side of the first metatarsophalangeal joint (b) with the medial side of the hallux (c). d Measurement of rearfoot angle (θ3), which was defined as the angle between the bisection of the lower one-third of the leg (bc) and the bisection of the calcaneus (ab). Note that the measurement procedures of foot length and navicular height are not indicated in this figure