## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Hook Position**} & \multicolumn{2}{c}{**Anterior Acromion**} & \multicolumn{2}{c}{**Middle Acromion**} & \multicolumn{2}{c}{**Posterior Acromion**} \\ \hline
**Posterior Hook Offset** & **0 mm** & **5 mm** & **10 mm** & **0 mm** & **5 mm** & **10 mm** & **0 mm** & **5 mm** & **10 mm** \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} Reaction force \\ on acromion (N) \\ \end{tabular} } & X-Axis & \(-3.5615\) & \(-0.4431\) & \(-0.37351\) & \(-3.4105\) & \(-0.4572\) & \(-0.38434\) & \(-4.2696\) & \(-0.62777\) & \(-0.50583\) \\  & Y-Axis & \(-2.1026\) & \(-2.5631\) & \(-2.5622\) & \(-2.1436\) & \(-2.5634\) & \(-2.562\) & \(-2.0026\) & \(-2.4803\) & \(-2.4812\) \\  & Z-Axis & \(0.4186\) & \(1.4168\) & \(1.4555\) & \(0.45633\) & \(1.4107\) & \(1.4511\) & \(0.25256\) & \(1.3597\) & \(1.4068\) \\  & Total & \(4.157\) & \(2.9619\) & \(2.9703\) & \(4.054\) & \(2.9615\) & \(2.9694\) & \(4.7227\) & \(2.8974\) & \(2.8967\) \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Maximum stress \\ (MPa) \\ \end{tabular} } & Plate & \(44.944\) & \(74.086\) & \(74.503\) & \(30.718\) & \(73.785\) & \(74.059\) & \(44.162\) & \(73.357\) & \(73.872\) \\  & S1 & \(2.6561\) & \(0.17302\) & \(0.17333\) & \(2.0829\) & \(0.17919\) & \(0.18024\) & \(2.6496\) & \(0.18685\) & \(0.18839\) \\  & S2 & \(2.0644\) & \(5.3123\) & \(5.3011\) & \(1.8372\) & \(5.3895\) & \(5.5165\) & \(1.9973\) & \(5.5796\) & \(5.5942\) \\  & S3 & \(3.9743\) & \(16.426\) & \(16.46\) & \(4.7258\) & \(17.008\) & \(17.123\) & \(5.2918\) & \(17.813\) & \(17.978\) \\  & S4 & \(9.4925\) & \(32.812\) & \(32.778\) & \(11.137\) & \(34.008\) & \(34.102\) & \(12.17\) & \(35.307\) & \(35.463\) \\  & S5 & \(1.7393\) & \(6.7224\) & \(6.7844\) & \(1.998\) & \(6.9667\) & \(7.0806\) & \(2.206\) & \(7.4543\) & \(7.5953\) \\  & S6 & \(10.331\) & \(33.743\) & \(33.689\) & \(11.943\) & \(35.022\) & \(35.112\) & \(13.181\) & \(36.512\) & \(36.674\) \\  & Point P & \(0.91762\) & \(1.0059\) & \(1.0136\) & \(0.91661\) & \(1.0045\) & \(1.0127\) & \(0.90326\) & \(1.0195\) & \(1.0299\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The reaction force on the acromion and the stress on the clavicle hook plate, each screw, and at point P of the clavicle. Based on the above analysis, the existence of a posterior hook offset is the key variable of this mechanical analysis. The clavicle hook plate without a posterior hook offset has a greater reaction force on the acromion but less stress on the mid-third of the clavicle, which may increase the probability of subacromial osteolysis [8; 9; 13]. The clavicle hook plate with a posterior hook offset has less reaction force on the acromion but greater stress on the mid-third of the clavicle, which may increase the risk of peri-implant fracture [10; 12; 13]. The reaction force analysis of the different posterior hook offsets fixed at the anterior, middle, and posterior acromion shows that the groups without a posterior hook offset have a higher reaction force on the acromion than the groups with a posterior hook offset. In the group without a posterior hook offset, the hook fixed at the middle acromion exhibits a relatively lower reaction force on the acromion, whereas in the groups with a posterior hook offset, the hook fixed in three different positions causes little difference in the reaction force. There is a little difference in the reaction force at different fixed positions of the hook in the acromion, which can be explained biomechanically. The distance from the fixed end of the acromion to the hook fixed in the acromion can be used as a factor to discuss the change in the reaction force. However, for the overall structure, the differences in the distance between the hooks fixed in the anterior acromion, middle acromion, and posterior acromion are tiny when compared with the overall structure. Therefore, there is a little difference between the results on this factor.