Are Hook Plates Advantageous Compared to Antiglide Plates for Vertical Shear Malleolar Fractures?

This study was designed to evaluate the biomechanical properties of a hook plate (HP) vs an antiglide (AG) plate for supination-adduction (SAD)-ankle fractures. Identical polyurethane tibial models were obtained and vertical fractures were created. The fractures were stabilized with 1 of the following: one-third tubular plate in an AG fashion with 2 screws proximal to the fracture; an AG plate with an additional screw perpendicular to the vertical shear fragment (MAG), or an HP. Ten models were randomly assigned to each of the 3 groups. The constructs were tested in offset-axial loading and were evaluated for construct stiffness and load-to-failure. The MAG construct yielded better stiffness compared with the AG plate (P < .05) and the HP (P < .05). The plate stiffness of the HP construct compared with the AG was not significant (P = .350). In regards to load-to-failure, the difference between MAG and AG was 638 N, and MAG and HP was 530 N (both P < .05). The HP had a load-to-failure that was, on average, 108 N more than the AG but was not significant (P = .063). A one-third tubular plate in the MAG fashion provided a stable, strong construct for fixation of vertical shear medial malleolus fractures.