| Objective To design and validate a removable screw for anterior ring fixation in elderly fragility fractures of pelvis.Methods The titanium alloy removable screws consisted of a main screw, connecting screws, and screw sleeves. The connecting screws were threaded at both ends to connect with the main screw and screw sleeve, allowing for disassembly. The main screw was designed with a tapered cavity and multiple injection holes in the sidewall for bone cement placement. Finite element analysis software was used to analyze the stress distribution of the removable screws.Results The tapered design of the removable screws enables quick insertion, minimizing the impact on pelvic bone quality. The cavity and side hole design allows for bone cement injection, which increased the pull-out strength of the main screw. The removable design of the main screw and screw sleeve facilitates the removal of internal fixation hardware, meeting fracture fixation requirements and reducing secondary surgical trauma. The results of finite element analysis show that in the anterior pelvic ring model fixed with detachable screws and connecting rods, the maximum principal stresses of axial tension and axial compression loads (804.8 MPa and 840.9 MPa, respectively) both occurred in the connecting rods, which were well below the yield strength of titanium alloy, and no failure occurred.Conclusion The removable screw designed for anterior ring fixation of elderly fragility fractures of the pelvis is characterized by its safety and reliability, strong anti-pull-out force, easy disassembly, and reduced secondary trauma, indicating a promising potential for translational application. |
