Determination of mechanical stiffness of bone by pQCT measurements: correlation with non-destructive mechanical four-point bending test data

• Published in: Journal of biomechanics Vol. 37; no. 8; pp. 1289 - 1293
• Main Authors: Martin, Daniel E, Severns, Anne E, Kabo, J.Michael
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.08.2004; Elsevier Limited
• Subjects: Animals; Biomechanical Phenomena; Bone; Bone and Bones - diagnostic imaging; Bone and Bones - physiology; Bone density; Bone Density - physiology; Bones; Density; Elasticity; Humerus - diagnostic imaging; Humerus - physiology; Male; Mechanical stiffness; Older people; Osteoporosis; Rabbits; Studies; Tomography, X-Ray Computed - methods; Mechanical stiffness; Density; Bone
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2003.12.009

Mechanical tests of bone provide valuable information about material and structural properties important for understanding bone pathology in both clinical and research settings, but no previous studies have produced applicable non-invasive, quantitative estimates of bending stiffness. The goal of this study was to evaluate the effectiveness of using peripheral quantitative computed tomography (pQCT) data to accurately compute the bending stiffness of bone. Normal rabbit humeri ( N=8) were scanned at their mid-diaphyses using pQCT. The average bone mineral densities and the cross-sectional moments of inertia were computed from the pQCT cross-sections. Bending stiffness was determined as a function of the elastic modulus of compact bone (based on the local bone mineral density), cross-sectional moment of inertia, and simulated quasistatic strain rate. The actual bending stiffness of the bones was determined using four-point bending tests. Comparison of the bending stiffness estimated from the pQCT data and the mechanical bending stiffness revealed excellent correlation ( R 2=0.96). The bending stiffness from the pQCT data was on average 103% of that obtained from the four-point bending tests. The results indicate that pQCT data can be used to accurately determine the bending stiffness of normal bone. Possible applications include temporal quantification of fracture healing and risk management of osteoporosis or other bone pathologies.