Development of a Novel Anterolateral Anatomical Locking Plate: Design Rationale, Finite Element Analysis, and In Vitro Biomechanical Evaluation

Complex anteroposterior compression fractures (APCF) of the tibial plateau involving both anterolateral and posterolateral columns present significant challenges for conventional lateral locking plate fixation due to inadequate stability. Although dual-plate fixation or posterior approaches achieve rigid stabilization, they substantially increase surgical morbidity and neurovascular injury risk. This study developed a dual-arm anterolateral anatomical locking plate (DAALP) for single-approach fixation via a standard anterolateral incision and comparatively assessed its biomechanical performance. A digital APCF model was reconstructed from healthy adult CT data using Mimics, Geomagic Wrap, and NX software. Finite element analysis (FEA) in Abaqus evaluated stress distribution and displacement under uniform (1500 N) and eccentric (600 N, 40% lateral area) loads. Mechanical properties were verified via three-point bending tests, while a tibial phantom model underwent stepwise loading (500 N, 750 N) and failure testing with Digital Image Correlation (DIC) for displacement monitoring. Results demonstrated comparable bone stress and overall fragment displacement between DAALP and conventional plates. However, DAALP concentrated stress at the anterior extension-posterior arc junction (higher peak stress) while reducing screw stress (uniform load: 18.04 MPa vs. 22.65 MPa; eccentric load: 10.67 MPa vs. 16.34 MPa), mitigating screw loosening and articular collapse risks. Three-point bending confirmed DAALP met implant strength requirements with superior flexural stiffness versus conventional plates. Biomechanical testing revealed no significant difference in vertical displacement at 500 N and 750 N loads (DAALP: 0.21±0.04 mm vs. 0.31±0.05 mm; conventional: 0.43±0.12 mm vs. 0.67±0.26 mm), but horizontal displacement was reduced by >50% with DAALP (500 N: p<0.01; 750 N: p<0.001). The DAALP’s integrated dual-column design maintained axial stability equivalent to conventional plates while significantly enhancing shear resistance, reducing screw loosening risk, and preserving articular surface integrity. This device provides a minimally invasive, biomechanically robust solution for APCF fixation via a single anterolateral approach, fulfilling clinical requirements for reliable stabilization.