Prediction of bone strength in growing animals using noninvasive bone mass measurements

This study aims to test the hypothesis that non invasive bone mass measurements can be used to predict bone strength in a piglet model. Dual energy X-ray absorptiometry measurements of bone mineral content (BMC) bone mineral density (BMD), and bone area (BA) were obtained from four sets of bones (left and right humeri and femoral of 12 piglets (6-68 days and 2250-17660 g). Bone strength, defined by the energy to bone failure, fracture moment, and flexural rigidity, was determined from three point bending tests using an Instron material testing system. Results show that bone mass between left and right extremities was highly correlated (r = 0.96 to 0.99, P less than or equal to 0.001 all comparisons) and was similar for bone strength (r = 0.85 to 0.98, P < 0.01 all comparisons). However, based on the standard deviation of the difference between measurements from left and right extremities, the agreement between sides was better for bone mass than for bone strength measurements, For each set of bones, bone mass measurements were highly correlated with bone strength measurements (r = 0.68-0.99, P < 0.05-less than or equal to0.001). The predictive ability of bone mass on bone strength varied (adjusted r(2) = 0.41-0.97) depending on the bone tested and the measurement parameter used, although remained statistically significant in all instances (P < 0.05-<less than or equal to>0.001). We conclude that in developing organisms, noninvasive bone mass measurements are correlated with and predictive of bone strength. although bones from the same side and same anatomical site should be used for comparison purposes.