A Three-Dimensional Finite Element Musculoskeletal Model of the Human Foot Complex

A novel three-dimensional FE musculoskeletal model of the human foot complex with detailed subject-specific representation of all major anatomical structures was developed in this study, with the objective being to reveal responses of foot musculoskeletal components during gait. The model consists of 12 major muscle groups around talocrural, subtalar and metatarsal-phanlangeal joints, 85 ligaments including plantar fascia, 29 bones and plantar soft tissue. The FE foot model was used to investigate the foot mechanics in the mid-stance during walking. Only muscle forces and ankle joint forces acting on the talus bone were used to drive the model. The segmental inertia properties, contact mechanics and frictional properties were all considered. The predicted plantar surface pressure distribution pattern showed good agreement with the pressure plate record. In the mid-stance phase, the peak pressures were found in heel area, and the region under 1st similar to 5th metatarsal bones. It is found that the peak stress appeared in the lateral side of the 1st metatarsal and middle dorsal side of 2nd metatarsal bone, about 5.7MPa and 4.0MPa respectively. The pattern is reasonable considering that the ankle joint force was transmitted mainly from rear foot to fore foot through talonavicular joint and cuneonavicular joint in mid-stance and consequently the 1st similar to 3rd metatarsal bones sustain more load. The simulated foot plantar fascia and deep transverse metatarsal ligaments extensions also showed reasonable responses in mid-stance during walking.