IN-VIVO DETERMINATION OF HOMOGENIZED MECHANICAL CHARACTERISTICS OF HUMAN TIBIA - APPLICATION TO THE STUDY OF TIBIAL TORSION IN-VIVO

Objective. The study presents a method allowing the in vivo homogenise d characteristics of the tibiae of children to be assessed. Design. St udies have been performed on two groups of children: six normal childr en, aged from 5 to 16yr, and on four children, aged from 8 to 11 yr wi th tibial deformities. We analysed the tibial transverse sections from CT scans performed on the Left tibia of each child, Background. Most tibial torsion studies have only been based on geometrical parameters. Our study integrated mechanical and geometrical considerations. Metho ds. The finite element models and integration of mechanical properties were performed from CT scans. Then homogenised mechanical characteris tics (tensile stiffness, flexural stiffness and torsional stiffness) w ere calculated. Results. The homogenised mechanical characteristics de crease between 20 to 80% of the tibial length. The values increased wi th age for both groups of children. Children with abnormalities seem t o have values of tibial rigidities comparable with those of normal tib iae. Conclusions. By considering the mechanical and geometrical proper ties of the tibia in our study, we showed that the bone stiffness of c hildren is not altered with torsional deformities.