## 4 Results  
The values shown in Table 5 express the evaluated and maximum values of HMH stress in MPa (occurring at the locations with stress concentrators, i.e., notches). The equivalent HMH stress is generally determined by means of Equation (1). Extreme stress values occur locally in very small areas. The analysis also takes into account the so-called evaluated stress values occurring in the vicinity of the maximum (see Figure 13). Generally, the stresses occurring in the nail systems are considerably lower. \[\sigma_{\text{HMH}}=\sqrt{\sigma_{1}^{2}+\sigma_{2}^{2}+\sigma_{3}^{2}-( \sigma_{1}\sigma_{2}+\sigma_{2}\sigma_{3}+\sigma_{1}\sigma_{3})}, \tag{1}\]  
where \(\sigma_{1}\) (MPa) are principle stresses. \begin{table}
\begin{tabular}{c c c c} \hline  & & **\(\Sigma\) of Elements** & **\(\Sigma\) of Nodes** \\ \hline \multirow{4}{*}{Medin a.s.} & \multirow{2}{*}{Nail collo-diaphyseal angle 125\({}^{\circ}\)} & Healed femur & 111,447 & 188,515 \\  & & Broken femur & 114,990 & 193,606 \\ \cline{2-4}  & \multirow{2}{*}{Nail collo-diaphyseal angle 130\({}^{\circ}\)} & Healed femur & 101,685 & 172,160 \\  & & Broken femur & 103,090 & 174,794 \\ \cline{2-4}  & \multirow{2}{*}{Nail collo-diaphyseal angle 135\({}^{\circ}\)} & Healed femur & 102,524 & 173,702 \\  & & Broken femur & 104,092 & 176,498 \\ \hline \multirow{4}{*}{Tantum} & \multirow{2}{*}{Nail collo-diaphyseal angle 120\({}^{\circ}\)} & Healed femur & 113,942 & 190,439 \\  & & Broken femur & 109,578 & 183,865 \\ \cline{1-1} \cline{2-4}  & \multirow{2}{*}{Nail collo-diaphyseal angle 125\({}^{\circ}\)} & Healed femur & 110,558 & 185,967 \\ \cline{1-1}  & & Broken femur & 110,746 & 186,860 \\ \hline \end{tabular}
\end{table} 
Table 4: Mesh properties. Figure 12: Local mesh refinement for a Medin 125\({}^{\circ}\) nail. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Nail Material**} & \multirow{2}{*}{**Femur**} & \multirow{2}{*}{**(HMH)**\(\cdot\)**10\({}^{-2}\)/MPa/} & \multicolumn{2}{c}{**Medin**} & \multicolumn{2}{c}{**Tantum**} \\ \cline{4-7}  & & & **125\({}^{\circ}\)** & **130\({}^{\circ}\)** & **135\({}^{\circ}\)** & **120\({}^{\circ}\)** & **125\({}^{\circ}\)** \\ \hline \multirow{2}{*}{1.4441 steel} & Healed femur & \(\sigma_{ep}\div\sigma_{max}\) & 11.15 \(\div\) 12.55 & 5.69 \(\div\) 6.41 & 8.51 \(\div\) 9.58 & 7.46 \(\div\) 8.40 & 8.18 \(\div\) 9.21 \\ \cline{2-7}  & Broken femur & \(\sigma_{ep}\div\sigma_{max}\) & 7.22 \(\div\) 8.12 & 5.58 \(\div\) 6.28 & 9.84 \(\div\) 11.07 & 5.45 \(\div\) 6.13 & 8.56 \(\div\) 9.63 \\ \hline \end{tabular}
\end{table} 
Table 5: Stress values at F = 1 N results in 10\({}^{-2}\) MPa. From the values shown in Table 5 (stress from loading with unit force), it is possible to use the linear dependence of stress on force to calculate stress under different forces. This is used when considering gravitational acceleration g = 9.807 ms\({}^{-2}\) and loading with force of equivalent mass m = 100 kg (overloading of a single limb when standing on one foot). The calculation was carried out by means of Equations (2) and (3), and the resulting values are shown in Table 6. Examples of these calculations are given for the maximum stress for Medin 125\({}^{\circ}\) in a healed femur.