Influence of Gap Shape on Biomechanical Properties of Extra-Articular Distal Humeral Fracture – A Finite Element Study

Abstract

SUMMARY -Th e aim of the study was to assess the infl uence of gap shape on biomechanical results in extra-articular distal humeral fracture: with contact on the posterior part (by anterior gap) and contact on ulnar column (by radial gap). Th e goal was to examine if and to what extent did displacements decrease in comparison with previously examined parallel gap without bony contact. Th e fi nite element analysis on the three diff erent plate constructs was performed, i.e. parallel, perpendicular and newly designed Y shape plate were considered. Displacements were measured on articular surface and gap point. Th e most visible decrease of maximum displacements in the distal part of the model was detected in the Y plate model with axial loading: in case of anterior gap 58.5% and especially at radially formed gap 60.9%. Similarly, at axial loading, displacement at the analyzed point on fracture gap most signifi cantly decreased in Y plate model (by 49.4%) at posterior bony contact. Moreover, the latter showed displacement decrease by 68.5% at ulnar bone contact. Furthermore, if a longer radial plate than the ulnar one was used, varus stress could have been avoided. Study results suggested that suffi cient stability could be ensured with the newly designed Y shape plate.