Biomechanical comparison of three internal fixation configurations for low transcondylar fractures of the distal humerus

•Few previous studies concerning biomechanical properties of different internal fixation for low transcondylar fractures of the distal humerus.•Traditional orthogonal and parallel double-plate configurations, and PPMS construct (posterolateral plate + medial screw) were compared.•Axial loading, posterior bending, internal torsion for construct stiffness and failure test under axial loading for construct strength were tested.•Combining all results, the overall stiffness and strength of parallel configuration were superior to orthogonal and PPMS configurations.•PPMS configuration can provide adequate stability and stiffness comparable double-plate methods under axial loading. We aimed to evaluate the biomechanical stiffness and strength of different internal fixation configurations and find suitable treatment strategies for low transcondylar fractures of the distal humerus. Thirty 4th generation composite humeri were used to create low transcondylar fracture models that were fixed by orthogonal and parallel double plates as well as posterolateral plate and medial screw (PPMS) configurations (n=10 in each group) using an anatomical locking compression plate-screw system and fully threaded medial cortical screws. Posterior bending (maximum 50 N), axial loading (maximum 200 N) and internal rotation (maximum 10 N·m) were tested, in that order, for each specimen. Stiffness under different biomechanical settings among different configurations were compared. Another 18 sets of fracture models were created using these three configurations (n=6 in each group) and the load to failure under axial loading among different configurations was compared. Under posterior bending, the stiffness of parallel group was higher than orthogonal group (P