Table 4.
Comparison of Mean Biomechanical Properties and Biochemical Composition Between Endplate Cartilage Samples With and Without Histologic Evidence of Damage
| No Damage (n = 12 Endplates) | Damage (n = 8 Endplates) | % Differencea | p-Value | |
|---|---|---|---|---|
| A (MPa) | 0.25 ± 0.19 | 0.22 ± 0.12 | –15.4 | 0.74 |
| B | 30.5 ± 10.2 | 21.2 ± 5.8 | –30.2 | 0.15 |
| Tensile modulus, E0% (MPa) | 6.6 ± 4.4 | 4.8 ± 3.5 | –27.7 | 0.50 |
| Energy dissipation, C (MPa) | 0.031 ± 0.010 | 0.041 ± 0.013 | 31.3 | 0.18 |
| Short relaxation constant, τ1 (s) | 4.7E–5 ± 5.3E–5 | 7.3E–5 ± 6.7E–5 | 55.3 | 0.48 |
| Long relaxation constant, τ2 (s) | 382 ± 132 | 336 ± 187 | –12.1 | 0.64 |
| Water content (%) | 42.3 ± 7.3 | 35.8 ± 8.1 | –15.4 | 0.15 |
| GAG content (μg/mg dry wt) | 108.3 ± 21.3 | 87.1 ± 21.3 | –19.6 | 0.20 |
| Collagen content (μg/mg dry wt) | 593.4 ± 107.8 | 506.1 ± 75.2 | –14.7 | 0.20 |
Data given as mean ± 95% CI.
a
Percent difference calculated with respect to the “No damage” mean values.