Analysis of load distribution on the plate and lateral hinge of a valgus opening high tibial osteotomy during weight-bearing: a finite element analysis - 24/07/24

Doi : 10.1016/j.otsr.2024.103956

Matthieu Ehlinger ^a,^b,⁎ , Wiayo Azoti ^c,^d, Lil Le Crom ^a, Samuel Berthe ^a, Matthieu Ollivier ^e, Henri Favreau ^b, Mekki Tamir ^b, Nadia Bahlouli ^a
^a ICube Laboratory - University of Strasbourg – CNRS, 4 rue de la Manufacture des Tabacs, 67000 Strasbourg, France
^b Department of Orthopedic Surgery and Traumatology, Hautepierre II Hospital, 1 Avenue Molière, 67098 Strasbourg Cedex, France
^c INSA Toulouse, 135 Avenue de Rangueil, 31400 Toulouse, France
^d Clément Ader Institute (ICA), Federal University Toulouse Midi-Pyrénées, UMR CNRS 5312, INSA, ISAE-SUPAERO, IMT Mines Albi, UPS, 3 rue Caroline Aigle, 31400 Toulouse, France
^e Department of Orthopedic Surgery, Sainte-Marguerite Hospital, University Hospital of Marseille, 270 Boulevard Sainte-Marguerite, 13009 Marseille, France

^⁎Corresponding author.

Sous presse. Épreuves corrigées par l'auteur. Disponible en ligne depuis le Wednesday 24 July 2024

Abstract

Introduction

Valgus high tibial osteotomy (HTO) is indicated for managing isolated medial knee osteoarthritis in a young patient with a metaphyseal deformity of the proximal tibia. In a medial opening HTO, maintaining the integrity of the lateral hinge is crucial for ensuring proper healing and correction retention. Using a locked plate to stabilize an HTO is common practice, allowing for earlier weight-bearing. The objective of this study was therefore to measure and track the mechanical load distribution on a locked fixation plate and the lateral hinge of an HTO using a finite element (FE) model simulating single-leg stance loading.

Hypothesis

The working hypothesis was that during weight-bearing, the plate and the lateral hinge absorb stress asymmetrically, predominantly on the plate.

Material and methods

A numerical model of an HTO stabilized with a locked plate was developed based on the actual geometry of a healthy proximal tibia (using Autodesk Fusion 360 and Altair HyperWorks software). In this finite element simulation of loading, a mesh convergence study was conducted to optimize the accuracy of the numerical model results. The primary outcome measure was the maximum stress value in the affected areas (Von Mises stress, in MPa) of the plate and the lateral hinge.

Results

The maximum stress intensity in the plate was approximately 20.29 MPa. The maximum stress intensity in the bony hinge was about 5.6 MPa. The results of the mesh convergence study for the hinge and the plate enabled defining the most suitable model for future FE studies: a 4 mm mesh for all model elements except for the high-stress area in the plate and the hinge, which were meshed with a 0.7 mm element size. This adaptation provided greater precision in the study.

Discussion

There is a distribution and allocation of stress both on the plate and the hinge, underlining the significance of the plate and the absolute necessity of preserving the hinge. Predictably, the plate absorbs the majority of the load, more than three times that of the hinge.

Conclusion

The hypothesis is confirmed; however, additional studies would be necessary to validate these numerical results: an experimental component on instrumented cadaveric bones, as well as comparative studies of different fixation plates.