## 4 Discussion  
Displaced GT fractures, considered as being uncommon, have remained less well understood. In a young population, these fractures occur with standard bone quality as a result of high-energy trauma. Also, most of these types of fractures are caused by impaction of the GT onto the anterior surface of the glenoid or traction force generated by the rotator cuff muscle. Various treatment options were used earlier, but no optimal fixation methods are reported in the literature. Surgical techniques to fix displaced GT fractures have been used, including suture fixation, tension band wire, percutaneous screw fixation, and plate fixation. [PERSON] et al. studied the GT fracture treatment for 11 treatment cases with locking compression plates and showed the results that the fractures had achieved union in all cases, and the patient's shoulder range of motion was not affected [4]. The report by [PERSON] et al. demonstrated a more accurate restoration of fractured fragments using an arthroscopic-assisted bone plate for the treatment of displaced large-sized comminuted GT fractures in 11 patients [6]. [PERSON] et al. reported on 8 months of outcomes of internal fixation using a mesh plate in GT fractures in nine patients in whom the fracture has healed with no problem of malunion and implant damage [3]. [PERSON] et al. evaluated the F3 Biomet plate fixation in GT fractures of 11 patients and found good results in fracture healing in all the cases [5]. The present study resulted in similar findings and supported that the displaced GT fracture could be successfully fixed with locking plates. Despite its common usage, locking plate fixation for GT fracture is associated with some limitations and disadvantages in clinical application [3; 5; 6; 7]. To our knowledge, only a few biomechanical studies has been investigated in GT-fracture-treated shoulders involving rotator cuff muscles that affect rehabilitation activities [11; 12; 27]. [PERSON] et al. found greater biomechanical effects at a high shoulder abduction position for the conventional double-row technique and at low abduction angles for the bridging sutures technique in their studies [12]. [PERSON] et al. resulted that the fixation techniques of double row suture anchor and suture bridge had superior initial fixation strengths at a low and high abduction angles, respectively, whereas the screw fixation technique was unaffected in their humeral GT fracture treatment study [27]. However, these studies were limited to only abduction movements for various angles of the humerus in their analyses. After surgery, the biomechanical properties of the repaired GT fragment were influenced by shoulder positions and activities, because the load on the GT fragment varies with shoulder positions and activities. Thus, the present study considered three types of shoulder rehabilitation activities including abduction, flexion, and horizontal flexion for various positions [26]. Optimizing the shoulder rehabilitation exercises is necessary to avoid the failure of GT fracture fixation after surgery. With rehabilitation exercises after a GT fracture treatment using locking plates, the shoulder functions can be regained in the shortest possible time. Therefore, activity must be started at the earliest after fracture fixation. During the early stages after fracture treatment, maintaining the controlled stresses throughout the fracture site will optimize fracture healing without increasing complications. The current research sought to explore the biomechanical results of the bone plate treatment strategy for shoulder joint rehabilitation of a GT fracture. Based on clinical trials, it is difficult to analyze the biomechanical behaviors of the repaired shoulder joint. Also, studying mechanically the behavior of cadaveric specimens for rehabilitation activities can be challenging due to bone anatomy variations, bone density, and bone fracture pattern. These problems could be solved using a numerical approach.