Elastic and elastic–plastic theoretical and numerical analyses are performed to evaluate the bone containing initial crack. The mode I þ II of fracture is applied to identify the most critical incline crack and the analytical results are compared with experimental evaluation. The loading capacity in bones with smaller thickness decreases more significantly in the elastic–plastic analysis. Both plastic zone and the elastic–plastic stress are higher in smaller initial crack length. Simultaneous initiation of non-close multiple cracks has no significant influence on the ultimate tensile load and the effect of crack width on fracture decreases in higher crack width and longer length.