Mechanical Testing

Whole bone mechanical properties were assessed in four-point bending as previously described [21] and in accordance with recommendations [26]. The anterior surface of each femur was placed on two lower supports with a span length of 9 mm and an upper span length of 3 mm. Specimens were loaded to failure at a rate of 2 mm/min, producing a force-displacement curve for each sample. Using a custom MATLAB program [24], structural and apparent material properties were determined. Apparent material properties were derived using standard beam-bending equations for four-point bending and geometric data from microCT analyses.