Travmatologiâ i Ortopediâ Rossii (Dec 2022)
Comparative Biomechanical Analysis of Ankle Arthrodesis Techniques: Experimental Study
Abstract
Background. Despite the existing significant number of various techniques for ankle arthrodesis, a number of authors point to certain technical difficulties of these operations, the loss of the talus and tibia position during ankylosing, nonunion. The problem of the ankle arthrodesis technique improving requires new solutions. The aim of the study was to compare the stability of various fixation systems in ankle arthrodesis by the finite element method. Methods. The finite element method was used to evaluate the biomechanical characteristics of three variants of ankle arthrodesis systems: three cancellous screws, the originally designed plate combined with two cancellous screws, when the screw in the proximal plates hole is cortical, and the same plate combined with two cancellous screws, when the screw in the proximal plates hole with angular stability. The stresses and strains under the application of various types of loads are studied. Results. In the anterior plate ankle fixation model combined with two cancellous screws and a proximal cortical screw, the implants and the talus experienced the least stresses compared to the other two models. Thus, the maximum equivalent stress in implants in the second variant was 68-124 MPa, in the first variant 92-147 MPa, in the third variant 130-331 MPa. The equivalent stress in the talus in the second version of fixation ranged from 20 to 46 MPa, in the first and third versions 28-58 MPa and 47-65 MPa, respectively. The indicators of maximum contact pressure at the border of the tibia and talus turned out to be the highest in the first variant compared to the other two models (34 MPa, 31 MPa and 31 MPa, respectively). Conclusions. Among the studied ankle fixation systems for arthrodesis, an anterior plate combined with two cancellous screws and a proximal cortical screw is the most preferable in terms of biomechanics.
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