Mechanical behaviour of trabecular bone of the human femoral head in females

The ultimate stress, Young's modulus, energy absorbed to ultimate stress, actual and apparent densities were determined for specimens of human trabecular bone taken perpendicular to the subchondral plate from female patients undergoing hip replacement for osteoarthrosis or fracture of the neck of femur and from age matched female cadavers. Higher mechanical properties were found in the major than in either the partial minor weight bearing areas of the femoral head in the cadaveric and the fractured neck of femur groups as well as in the eburnated when compared to the non-eburnated areas of the osteoarthrotic groups. For all areas, the mechanical properties were higher in the osteoarthrotic than the cadaveric femoral heads which were again higher than those in the osteoporotic group. It is concluded that the major weight bearing areas are most affected by the pathological processes which are responsible for either fracture of the neck of femur or osteoarthrotic degradation. Regression analysis was used to relate the mechanical properties with the bone density providing evidence that cadaveric and fractured neck of femur bone can be regarded as mechanically uniform.