Foot ulcer prevention using biomechanical modelling

• Published in: Computer methods in biomechanics and biomedical engineering. 2014-10, Vol.2 (4), p.189-196
• Main Authors: Luboz, V., Perrier, A., Stavness, I., Lloyd, J.E., Bucki, M., Cannard, F., Diot, B., Vuillerme, N., Payan, Y.
• Format: Article
• Language: English
• Subjects: Bioengineering; biomechanical model; Biomechanics; Engineering Sciences; foot ulcer prevention; Life Sciences; Mechanics; Physics
• ISSN: 2168-1163; 2168-1171
• DOI: 10.1080/21681163.2013.837410

Foot ulcers are a common complication of diabetes and are the consequence of trauma to the feet and a reduced ability to perceive pain in persons with diabetes. Ulcers appear internally when pressures applied on the foot create high-internal strains below bony structures. It is therefore important to monitor tissue strains in persons with diabetes. We propose to use a biomechanical model of the foot coupled with a pressure sensor to estimate the strains within the foot and to determine whether they can cause ulcer formation. Our biomechanical foot model is composed of a finite element mesh representing the soft tissues, separated into four Neo-Hookean materials with different elasticity: plantar skin, non-plantar skin, fat and muscles. Rigid body models of the bones are integrated within the mesh to rigidify the foot. Thirty-three joints connect those bones around cylindrical or spherical pivots. Cables are included to represent the main ligaments in order to stabilise the foot. This model simulates a realistic behaviour when the sole is subjected to pressures measured with a sensor during bipedal standing. Surface strains around 5% are measured below the heel and metatarsal heads, while internal strains are close to 70%. This strain estimation, when coupled to a pressure sensor, could consequently be used in a patient alert system to prevent ulcer formation.