Is augmented femoral lateral plating with helically shaped medial plates biomechanically advantageous over straight medial plates?

Abstract

BackgroundDual plating of comminuted distal femoral fractures allows for early patient mobilization. An additional helically shaped medial plate avoids the medial vital structures of the thigh. Aim: to investigate the biomechanical competence of augmented lateral locking compression plate distal femur (LCP‐DF) using an additional straight versus a helically shaped medial LCP of the same length.MethodsTen pairs of human cadaveric femora were instrumented with a lateral anatomical 15‐hole LCP‐DF. Following, they were pairwise instrumented with either an additional medial straight 14‐hole LCP (group1) or a 90°‐helical shape LCP (group2). All specimens were biomechanically tested under quasi‐static and progressively increasing combined cyclic axial and torsional loading until failure.ResultsInitial interfragmentary axial displacement and flexion under static compression were significantly smaller in group1 (0.11±0.12mm and 0.21±0.10°) versus group2 (0.31±0.14mm and 0.68±0.16°), p≤0.007. Initial varus deformation under static compression remained not significantly different between group1 (0.57±0.23°) and group2 (0.75±0.34°), p=0.085. Flexion movements during dynamic loading were significantly higher for group2 (2.51±0.54°) versus group1 (1.63±1.28°), p=0.015, however, no significant differences were observed in terms of varus, internal rotation, axial and shear displacements between the groups, p≥0.204. Cycles to failure and load at failure were higher in group2 (25172±6376 and 3017N±638N) compared to group1 (22277±4576 and 2728N±458N) with no significant differences between them, p=0.195.ConclusionFrom a biomechanical perspective, helical double plating may be considered as useful alternative to straight double plating, demonstrating ameliorated damping capacities during flexion deformation and safer application as the medial neurovascular structures of the thigh are avoided.This article is protected by copyright. All rights reserved.