Bone mass, areal, and volumetric bone density are equally accurate, sensitive, and specific surrogates of the breaking strength of the vertebral body: An in vitro study

✍ Scribed by Aaron D. Tabensky; Vanessa Deluca; Esther Briganti; Ego Seeman; John Williams

• Publisher: American Society for Bone and Mineral Research
• Year: 2010
• Tongue: English
• Weight: 936 KB
• Volume: 11
• Category: Article
• ISSN: 0884-0431
• DOI: 10.1002/jbmr.5650111221

✦ Synopsis

The validity of the bone mineral density (BMD) measurement depends on its accuracy as a predictor of the breaking strength of bone. As the breaking strength is proportional to the square of the apparent density, a small error in the calculation of BMD may result in a larger error in the predicted bone strength. The aims of this study were (i) to determine whether inaccuracies in the measurement of the dimensions, projected area, and volume of the vertebral body (used to derive the areal and volumetric BMD) result in errors in the predicted breaking strength and (ii) to compare the accuracy, sensitivity, and specificity of bone mineral content (BMC), areal BMD, volumetric BMD, and volumetric bone mineral apparent density (BMAD) as surrogates of bone strength. We measured the BMC (by densitometry), dimensions and volume (using calipers, densitometry, the Carter et al, and Peel and Eastell methods), and breaking strength (using the Instron 1114 apparatus, Newtons, N) 0£22 vertebral body specimens. All methods resulted in errors in height, width, and depth between -11.3 ± 1.0 and 30.4 ± 1.8% relative to the "gold" standard caliper method. The vertebral body volume (of 38.0 ± 1.2 cm 3 ) measured by submersion was used as the gold standard to derive the volumetric BMD gold standard (of 0.162 ± 0.01 glcm 3 ) . All methods, except the Peel and Eastell method, resulted in errors ranging between -10.7 ± 1.5 and 56.9 ± 3.4% in vertebral body volume and -35.6 ± 1.5 to 12.6 ± 1.8% in volumetric BMD (all p < 0.0005). The same absolute Breaking Strength ...