Biomechanical comparison of orthogonal versus parallel double plating systems in intraarticular distal humerus fractures

Abstract

Objectives: In intraarticular distal humerus fractures, internalŞxation with double plates is the goldstandard treatment. However the optimal plate conŞguration is not clear in the literature. The aim of thisstudy was to compare the biomechanical stability of the parallel and the orthogonal anatomical lockingplating systems in intraarticular distal humerus fractures in artiŞcial humerus models.Methods: Intraarticular distal humerus fracture (AO13-C2) with 5 mm metaphyseal defect was created insixteen artiŞcial humeral models. Models were Şxed with either orthogonal or parallel plating systemswith locking screws (Acumed elbow plating systems). Both systems were tested for their stiffness withloads in axial compression, varus, valgus, anterior and posterior bending. Then plastic deformation aftercyclic loading in posterior bending and load to failure in posterior bending were tested. The failuremechanisms of all the samples were observed.Results: Stiffness values in every direction were not signiŞcantly different among the orthogonal and theparallel plating groups. There was no statistical difference between the two groups in plastic deformationvalues (0.31 mme0.29 mm) and load to failure tests in posterior bending (372.4 Ne379.7 N). In theorthogonal plating system most of the failures occurred due to the proximal shaft fracture, whereas inthe parallel plating system failure occurred due to the shift of the most distal screw in proximal fragment.Conclusion: Our study showed that both plating systems had similar biomechanical stabilities whenanatomic plates with distal locking screws were used in intraarticular distal humerus fractures in artiŞcial humerus models.© 2016 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V. This isan open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)