Table 1 Material properties used in finite-element model
Material Properties | Young’s Modulus (E: MPa) | Poisson’s Ratio (μ) |
|---|---|---|
Osteoporotic cortical bone | 8040 (67% of normal) | 0.3 |
Osteoporotic cancellous bone | 34 (34% of normal) | 0.2 |
Cartilage | 50 | 0.3 |
Endplate | 1000 | 0.3 |
Annulus fibrosus | 4.2 | 0.45 |
Nucleus pulposus | 1 | 0.499 |
Ligament | ||
 Anterior longitudinal | 20 | 0.3 |
 Posterior longitudinal | 20 | 0.3 |
 Transverse | 59 | 0.3 |
 Ligamentum flavum | 19.5 | 0.3 |
 Interspinous | 12 | 0.3 |
 Supraspinous | 15 | 0.3 |
 Capsular ligament | 7.5 | 0.3 |
Spinal instrumentation (titanium alloy) | 110,000 | 0.28 |
Bone cement (PMMA) | 3000 | 0.4 |
Spinal cage (polyetheretherketone) | 3600 | 0.25 |