Evaluation of Hallux Valgus Using Rotational Moment of Midfoot Measured by a Three-dimensional Foot Scanner: a Cross-sectional Observational Study

The mechanism of hallux valgus (HV) development has not been fully clarified, and a new evaluation method is required. We aimed to establish for calculating the rotational moment midfoot (RMM) by developing three-dimensional foot scanner, reveal features HV using this method. A smartphone was used capture images analyze regions in 592 participants. focused on feature points such as great toe-first metatarsal head-heel (GFH) angle angle, navicular bone, centerline foot. Navicular-moment-arm (NMA) defined distance between bone RMM calculated from NMA body weight. mean values were 12.3 9.4 Nm male female participants, respectively. With pronation midfoot, load increased because increase adduction axis (ABD). ABD with increasing GFH quartiles In particular, significantly higher at fourth quartile angle. Transverse arch width height identified predictors both showing high contribution. associated controlled mainly posterior tibial muscle. Dysfunction muscle causes an NMA, leading first second (M1-M2) Therefore, increases cause pronate rotate, inducing M1-M2 applied affects adjacent medial intermediate cuneiform bones. Particularly, motion rotate conjunction, possibly relaxation tarsometatarsal joint metatarsus primus varus. Measurement skeletal structure potential widespread use.