Table 2.
Bone mechanical properties following partial weightbearing ± radiation exposure for 21 days (post partial weightbearing) and after 21 additional days to assess long-term response (post recovery)
| WB-Sham | WB-Rad | G/6-Sham | G/6-Rad | |
|---|---|---|---|---|
| Post partial weightbearing | ||||
| Mid-shaft Femur 3-point Bend | ||||
| Ultimate load (N) | 18.6 ± 2.50 | 19.8 ± 1.90 | 19.6 ± 2.50 | 17.4 ± 2.10 |
| Stiffness (N/mm) | 91.6 ± 2.80 | 94.7 ± 14.90 | 101 ± 19.8 | 97.0 ± 18.3 |
| Femoral neck compression | ||||
| Ultimate load (N) | 11.2 ± 1.80 | 11.4 ± 1.30 | 10.0 ± 1.50 | 11.1 ± 0.80 |
| Stiffness (N/mm) | 28.9 ± 7.90 | 30.5 ± 12.2 | 23.0 ± 7.30 | 31.4 ± 7.23 |
| Post recovery | ||||
| Mid-shaft Femur 3-point Bend | ||||
| Ultimate load (N) | 20.5 ± 1.43 | 22.1 ± 2.13 | 21.7 ± 1.70 | 19.6 ± 1.80 |
| Stiffness (N/mm) | 89.0 ± 8.9 | 95.4 ± 36.6 | 79.5 ± 18.5 | 95.7 ± 26.5 |
| Energy-to-ultimate (mJ) | 3.05 ± 0.63 | 3.02 ± 0.06 | 3.32 ± 0.43 | 3.34 ± 0.92 |
| Energy-to-fracture (mJ) | 6.65 ± 1.60 | 4.79 ± 0.30 | 5.20 ± 1.24 | 4.66 ± 1.74 |
| Postyield energy (mJ) | 5.40 ± 1.73 | 3.33 ± 0.18 | 3.84 ± 1.33 | 3.35 ± 1.61 |
| Femoral neck compression | ||||
| Ultimate load (N) | 11.1 ± 1.75 | 12.0 ± 1.82 | 10.7 ± 1.79 | 11.4 ± 0.7 |
| Stiffness (N/mm) | 33.8 ± 12.1 | 25.3 ± 3.85 | 25.7 ± 6.50 | 29.1 ± 12.2 |
Two different mechanical tests are represented following 0.5 Gy 56Fe and/or G/6 for 21 days (Post partial weightbearing) and for separate groups maintained for 21 additional days of full weightbearing recovery (Post recovery). Mid -shaft femurs were subjected to three-point bending to failure and femoral necks to axial compression with quasi-static loading rates. WB weightbearing, Sham no exposure to radiation, Rad acute dose of 0.5 Gy 56Fe, G/6 partial weightbearing. Group means that share the same letter are not statistically different from one another (p < 0.05); pairwise comparisons generated from Kruskal–Wallis ANOVA (data not normally distributed)