Comparing Simulation Approaches Used in Finite Element Modelling of a Medial Opening Wedge High Tibial Osteotomy

Abstract

Purpose: Medial opening wedge high tibial osteotomy is a surgical procedure intended to relieve the symptoms of osteoarthritis in the medial compartment of the knee by addressing malalignment within the structures of the knee. In previous studies, the osteotomy cut and wedge opening in a Medial opening wedge high tibial osteotomy finite element model has been represented using either one of two techniques, which we define herein as wedge opening and wedge removal approaches. The purpose of this study is to determine whether the wedge removal for a medial opening wedge high tibial osteotomy finite element modelling study predicts accurate stresses and strains in the plate, screw, and throughout the proximal tibia, in comparison to the wedge opening.

Methods: Seven tibia models were reconstructed from CT scans of seven cadaveric specimen. Two sets of models were created from the same set of specimens to create the wedge opening (n = 7) and wedge removal (n = 7) dataset.

Results: A statistically significant difference in the mean plate stresses, screw stresses, and stresses in the tibia at the region around the apex of the osteotomy were found with the wedge removal, resulting in 4-59% greater stresses.

Conclusion: The wedge removal is not an accurate representation of a medial opening wedge high tibial osteotomy with respect to the wedge opening. Selecting the appropriate modelling method that best represents the clinical scenario is the first crucial step in creating a representative finite element model.

Keywords: Finite element analysis; HTO; Osteotomy; Stress analysis.