[Biomechanical analysis of the medial arch of the foot based on a rigid body spring model].
A system (program) using a rigid body spring model was employed, in which computer simulation would be able to analyze the stress distributions of the midtarsal joint, the cuneionavicular joint and the tarsometatarsal joint which form the medial arch of the foot. Measurements were taken using Yokokura's method, with Hibbs' angle measured from an X-ray image of the foot. A correlation between the results of the stress analysis and the radiographical measurements was then investigated. A total of 127 feet were studied involving 85 females with a mean age of 42.1 years. Cy, Ny and Ly using Yokokura's method were 30.9 +/- 3.7 mm%, 26.5 +/- 3.6 mm%, and 20.7 +/- 2.8 mm%, respectively, and the Hibbs' angle was 143.8 +/- 6.7 degrees. The stress distributions of the midtarsal joint, the cuneionavicular joint and the tarsometatarsal joint were 28.0 +/- 1.3 kg, 30.8 +/- 2.0 kg, and 26.6 +/- 1.6 kg, respectively. The greatest stress of the three joints was found at the cuneionvicular joint, followed by the midtarsal joint, and with the least stress found at the tarsometatarsal joint. There appeared to be a direct correlation between a flattening in the foot (a decrease in the arch) and an increase in stress distributed on the medial arch.
Tominaga
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Department of Orthopaedic Surgery, St. Merianna University School of Medicine, Kanagawa, Japan.
D001696:Biomechanical Phenomena; D003198:Computer Simulation; D005260:Female; D005528:Foot / Q000502:physiology*; D006801:Humans; D008683:Metatarsophalangeal Joint / Q000502:physiology; D008954:Models, Biological; D011312:Pressure; D013314:Stress, Mechanical