The geometrical properties of human femur and tibia and their importance for the mechanical behaviour of these bone structures.

A series of non pathological human tibial and femoral bones have been tested in torsional loading at high strain rates. Elastic (torsional stiffness) and ultimate properties (Tmax) have been determined. A geometrical description of the individual bone structures has been performed by determination of the polar moment of inertia (assuming axial symmetry), variation of this parameter along the long axis of the bone and length of the specimen between the grips. A fairly accurate prediction of mechanical behaviour of bone structures could be obtained using these geometrical parameters. The high variation of elastic and ultimate properties of whole bone structures in torsional loading is primarily the result of the high variation of polar moment of inertia for the different bone specimens.