Metatarsal fracture is one of the most common foot injuries, particularly in athletes and soldiers, and is often associated with landing in inversion. An improved understanding of deformation of the metatarsals under inversion landing conditions is essential in the diagnosis and prevention of metatarsal injuries. In this work, a detailed three-dimensional (3D) finite element foot model was developed to investigate the effect of inversion positions on stress distribution and concentration within the metatarsals. The predicted plantar pressure distribution showed good agreement with data from controlled biomechanical tests. The deformation and stresses of the metatarsals during landing at different inversion angles (normal landing, 10 degree inversion and 20 degree inversion angles) were comparatively studied. The results showed that in the lateral metatarsals stress increased while in the medial metatarsals stress decreased with the angle of inversion. The peak stress point was found to be near the proximal part of the fifth metatarsal, which corresponds with reported clinical observations of metatarsal injuries.

This pilot study analyzed the loading on the medial forefoot (MF) region during walking in high-heel shoes. Eight healthy female volunteers have participated in this study with the heel height varied from 0 cm (flat), 4.5 cm (low), and 8.5 cm (high). The results showed that the load on MF increased with the heel height and the magnitude of the load could be effectively reduced by using foam inserts. Comparative studies of foams with different hardness and thicknesses showed that thicker soft foams had a significant advantage over thiner hard foams (P < 0.05) in reducing the peak pressures. An optimum condition with a thick soft insert could reduce MF pressure by 26%, impact force by 27%, and force time integral by 20% when compared to the condition without insert.