Abstract:Objective To analyze the influence of shaping on the bending strength of bone plates and the influence of different locking nail distributions on plate force to provide biomechanical references for shaping plates and selecting different locking nail distributions. Methods Finite element simulation analysis of the four-point bending strength of a plate was performed according to the YY/T 0342—2020 standard. Theoretical analysis and finite element simulation methods were used to analyze the force on prosthesis models with different lock-nail distributions. Results At 30° bending, the 3.7 mm-thick plate had 28% higher equivalent plastic strain than the 2.7 mm-thick plate. The 3.7 and 2.7 mm-thick plates had ultimate bending angles of 55° and 67°, respectively. The crease had little impact on the plate stress. The four-point bending strength and equivalent bending stiffness of the unshapeed structure were 2.64 N?m and 1.12 N?m2, respectively. The four-point bending strength and equivalent bending stiffness with the crease were 2.63 N?m and 1.10 N?m2, respectively. After forward and backward bending, the four-point bending strength of the plate decreased from 2.64 to 2.45 N?m by approximately 7.72%,and the equivalent bending stiffness decreased from 1.12 to 0.98 N?m2 by approximately 12%. The impact was obvious. After implantation of tamponade screws, the four-point bending strength of the single-hole plate improved significantly from 2.64 to 3.15 N?m, by approximately 19.32% and the equivalent bending stiffness increased from 1.12 to 1.14 N?m2, by approximately 2.1%. At least two locking holes were reserved on both sides of the fracture line. Not inserting the locking screw reduced the stress by approximately 50% compared with the full insertion of the locking screw. During 15-week postoperative walking without bone callus formation, the material stress of TC4 reached 852.7 MPa and yielding occurred. Conclusions In a clinical scenario where larger shaping is required, it is not suitable for plates with larger thicknesses and plate fractures are more likely to occur after large-thickness shaping. This can guide the clinical selection of plates with appropriate thickness based on the shaping angle, and tamponade screws can be implanted in extreme cases. Fixing locking screws clinically is recommended; however, a method of fixing the locking screws with full screws is not recommended. The biomechanical effect was best when two locking holes at both ends of the fracture line were maintained without fixing the locking screws.