Tibia Bending: Strength and Response 851728

Unembalmed human tibias were subjected to static and dynamic three-point bending tests using the Wayne State Translational Impactor. Simple supports potted to the bone near the proximal and distal epiphyses were attached to force transducers and load was applied at midspan by a 32-kg impactor that had a rigid 25-mm diameter cylindrical contact surface. Loads were applied through the normal flesh covering the bone, and were directed from the anterior to posterior or from lateral to medial. Each bone was loaded once and sustained fracture at or near mid-span. Peak bending moments, impact speeds and load-deflection data are presented. Data regarding cross-sectional properties adjacent to the fracture site and mineral content of the specimens are included, along with a study of the correlations of strength with these various parameters. Midshaft fracture of the tibia occurred at bending moments of about 280 and 320 N.m for females and males, respectively, regardless of the direction of impact. The principal inertial axes of the tibial cross-section were oriented very nearly along the AP and SI directions. Local crushing of bone as a result of high compressive contact stresses never occurred.