Estimation of Young's Modulus and Apparent Density of Human Trabecular Bone by Spherical Indentatin Test and CT / 대한정형외과연구학회지

ABSTRACT

We intended to evaluate the Young's modulus of trabecular bone and apparent density from Computed Tomography(CT) and Spherical Indentation test and to quantify relation ship between them. The distal femurs(31 age, male, left and right) were prepared for exprimentatin and were embedded with repect to anatomical orientation. Then the specimens were scnned at 1 mm intervals on GE9800 CT scanner and the Hounsfield Units(HU, or CT number) were extracted from each CT image. After scanning, the bones were sectioned with diamond saw, producing 8 mm cubes of trabecular bone(72 eachs) from the metaphyseal region of both distal femur. The cubes were mechanically tested in inferior-superior(IS), anteriorposterior(AP), and medial-lateral(ML) direction with custom-made device, Spherical Indentatin Tester. After testing, the real apparent density of specimens were measured. The results of this study showed that the IS modulus was singificantly greater than both the AP and ML modulus and the AP modulus was also greater than ML modulus significantly(p<0.01). A linear relation ship between HU and real apparent density was found to be significant(R2=0.68) and significant power relationship between the apparent density and the tangent moduli(either by CT or physical measures) was also found.