Anterior plate supplementation increases ankle arthrodesis construct rigidity

Background: The success of ankle arthrodesis for the treatment of post-traumatic ankle arthritis depends on achieving and maintaining rigid fixation of the prepared tibiotalar interface. The purpose of this study was to examine the biomechanical effect of anterior plate supplementation of a popular three-screw fusion construct. Methods: Six fresh-frozen cadaver ankles were prepared and instrumented with three partially threaded screws compressing the tibiotalar interface. Testing was done with and without supplementary anterior plate fixation under three different decoupled loading conditions: plantarflexion/dorsiflexion, inversion/eversion, and rotation. Motion at the tibiotalar interface was recorded. Results: Anterior plating increased construct stiffness by a factor of 3.5, 1.9, and 1.4 for the sagittal, coronal, and torsion modes, respectively. Less motion occurred at the tibiotalar interface in all to the three different loading conditions (p = 0.031) with plate supplementation. Conclusions: Compared to screws alone, anterior plate supplementation increases construct rigidity and decreases micromotion at the ankle fusion interface.