Dynamic analysis of the transverse arch of the foot and its relationship with the hallux valgus / 中华骨科杂志

ABSTRACT

Objective To study the spatial change of transverse arch in the metatarsal head during a normal walking cycle, demonstrate the significance of transverse arch in normal walking and the relationship with hallux valgus. Methods A modeling gait cycle was obtained under the C- armed machine, the coronal spatial change of the transverse arch of the metatarsal head were recorded using video tape. On computer work station, the images from video tape were transformed to mpeg files. A model of the transverse arch was created for the analysis of the relationship between the transverse arch index Q and sinking time; between Q and I andⅡ intermetatarsal angle;Ⅰ andⅣ intermetatarsal angle; sinking time and body mass. Results There was a transverse arch formed by the 5 metatarsal heads. In normal walking, during standing phase to toe- off phase, the 2 and 3 metatarsal heads approach the ground resulting in sinking of the transverse arch. The transverse arch index had an adverse relationship with the hallux valgus angle. The time of the transverse arch sinking decrease accompanying with the transverse index Q. Conclusion The transverse arch of metatarsals played an important role during normal gait cycle. During normal walking, when the center of pressure moved forward, the force acting on the 2 and 3 metatarsal was increasing. So, the metatarsal heads drop down resulting in sinking of the transverse arch of the metatarsal head. In hallux valgus patients, the time of transverse arch sinking was earlier than normal and duration was longer. The total force acting on the 2 and (or) 3 metatarsal increased, which may caused disorder of forefoot.