Prediction of bone strength in growing animals using noninvasive bone massmeasurements

This study aims to test the hypothesis that non invasive bone mass measurem ents 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 (le ft 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 a nd right extremities was highly correlated (r = 0.96 to 0.99, P less than o r 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 devia tion of the difference between measurements from left and right extremities , the agreement between sides was better for bone mass than for bone streng th 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 th an 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 mea surement parameter used, although remained statistically significant in all instances (P < 0.05-<less than or equal to>0.001). We conclude that in dev eloping organisms, noninvasive bone mass measurements are correlated with a nd predictive of bone strength. although bones from the same side and same anatomical site should be used for comparison purposes.