Issue 40

I. Doulamis et alii, Frattura ed Integrità Strutturale, 40 (2017) 85-94; DOI: 10.3221/IGF-ESIS.40.08 90 Mechanical testing Some of the samples were damaged before testing during harvesting. In the end, the number of sample pairs (i.e. left and right femurs) that were tested was 3, 6, and 10 for groups A, B and C respectively. The average values and standard de- viations for all biomechanical parameters measured in the context of this study are presented in Tab. 1. Table 1 : The average values for the biomechanical parameters measured. The respective standard deviations are shown in brackets. One way ANOVA revealed statistically significant differences between the three groups in terms of minor axis length (b), major axis length (a) and thickness of the cross-section (t) and also in terms of ultimate stress (Fig. 4). No statistically significant difference was found in terms of force, stiffness or energy to failure. Figure 4 : Comparative results in terms of bone morphology and mechanical strength. The lengths of the minor axis (b), of the major axis (a), of cortical shell thickness and of ultimate stress are presented. More specifically the average minor axis (b) of group A was smaller than group's B and C by 12% (p=0.040) and 7% (p<0.001) respectively. The respective difference between groups B and C was 4% (p=0.041) with the minor axis of group Group: A B C Max Force (N) 16.4 14.2 15.6 (2.6) (2.6) (2.2) Stiffness (N/mm) 77 90 89 (25) (34) (28) Energy (N*mm) 3.16 2.64 3.36 (0.85) (0.92) (1.20) b (mm) 1.42 1.59 1.53 (0.06) (0.07) (0.11) a (mm) 2.05 2.19 2.16 (0.04) (0.10) (0.11) t (mm) 0.24 0.22 0.25 (0.03) (0.03) (0.04) Stress (MPa) 58 43 44 (12) (7) (11) * ** * * * * *