Postfailure compressive behavior of tibial trabecular bone in three anatomic directions.

To obtain information describing the postfailure behavior of human proximal tibial trabecular bone, cube specimens of bone were mechanically tested in compression beyond the point of failure. Tests were performed in the three anatomic directions, plots of stress versus strain were obtained, and measures to describe the stress-strain relations before, during, and after failure were defined. These measures included elastic modulus, strength, postfailure slope, strain during maximum stress, and first postfailure minimum stress. For each anatomic direction, analyses were performed to correlate these parameters with ash density. Each of these measures was significantly correlated with ash density at the p < 0.05 level for all test directions, except for postfailure slope, which was correlated in the mediolateral and superior-inferior directions, and strain during maximum stress, which was correlated only in the superior-inferior direction. The data from this study enable trilinear stress-strain relations to be estimated for proximal tibial trabecular bone of various densities, and can serve as a first step toward modeling the behavior of trabecular bone before, during, and after failure.