Biomechanical comparison of double mini-locking plate versus lateral locking plate for Danis-Weber B distal fibula fractures

Résumé fourni par la source

BACKGROUND: Lateral locking plate (LLP) is a successful standard treatment for Danis-Weber B distal fibula fractures. However, its uniplanar nature can be a limitation when insufficient bone is available at the distal fragment for secure screw fixation, particularly in low or osteoporotic fractures. This study evaluated the biomechanical performance of a novel biplanar double mini-locking plate (DMLP) system designed to address this challenge. METHODS: Twenty left fibula Sawbones models were used to simulate Danis-Weber B fractures. The samples were divided into two groups, Group A (DMLP) and Group B (LLP), with 10 samples in each group. Biomechanical testing included quasistatic axial compression, torsional loading, and torsional failure tests to assess the stiffness, displacement, failure mode, and failure torque. RESULTS: Biomechanical testing revealed that Group A exhibited superior structural properties compared with Group B. In the axial compression test, the compression stiffness of Group A was 31% greater than that of Group B (402.8 ± 100.4 N/mm vs. 308.4 ± 60.51 N/mm, p = 0.0202). In the torsion tests, Group A demonstrated significantly greater torsional stiffness within the 0.25–0.5 N·m range (0.42 ± 0.05 N·m/° vs. 0.29 ± 0.17 N·m/°, p = 0.0172) and the 0.5–1.0 N·m range (0.39 ± 0.03 N·m/° vs. 0.27 ± 0.16 N·m/°, p = 0.0191). Additionally, the failure torque in Group A was approximately 26% greater (14.21 ± 2.01 N·m vs. 11.24 ± 1.47 N·m, p = 0.0036). Digital image correlation (DIC) analysis revealed that Group A had significantly reduced relative displacement at the fracture site under axial compression (-0.12 ± 0.06 mm vs. -0.32 ± 0.15 mm, p = 0.0011) and at 10° of torsion (0.68 ± 0.14 mm vs. 1.23 ± 0.21 mm, p < 0.0001). All fractures occurred at the proximal end, with no significant difference in failure location between the two groups (p = 1.000). CONCLUSION: In this in vitro biomechanical study using Sawbones models, the DMLP demonstrated superior performance compared to the LLP for the fixation of simulated Danis-Weber B distal fibula fractures. Under the quasistatic loading conditions tested, the DMLP construct exhibited significantly greater axial stiffness, torsional stability, and failure torque. These findings provide a strong biomechanical rationale, based on this standardized experimental model, warranting further investigation for its potential clinical application. CLINICAL TRIAL NUMBER: Not applicable.

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