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

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Medical imaging

Background:

• Medial opening wedge high tibial osteotomy (MOWHTO) addresses knee osteoarthritis by correcting malalignment.
• Finite element modeling (FEM) is used to simulate MOWHTO, with two common techniques: wedge opening and wedge removal.
• Accurate FEM is crucial for understanding surgical outcomes and implant performance.

Purpose of the Study:

• To compare the accuracy of the wedge removal technique versus the wedge opening technique in MOWHTO FEM.
• To determine if wedge removal accurately predicts stresses in the plate, screw, and proximal tibia.

Main Methods:

• Seven cadaveric tibia models were created using CT scans.
• Two sets of FEMs were generated from each specimen: one using the wedge opening approach and one using the wedge removal approach.
• Stresses in the plate, screw, and proximal tibia were analyzed for both methods.

Main Results:

• The wedge removal method resulted in statistically significant differences in mean stresses.
• Plate stresses, screw stresses, and tibial stresses near the osteotomy apex were 4-59% higher with the wedge removal technique.
• These findings indicate a notable overestimation of mechanical load with the wedge removal method.

Conclusions:

• The wedge removal technique is an inaccurate representation of MOWHTO compared to the wedge opening technique.
• Accurate FEM requires selecting a modeling method that precisely reflects the clinical scenario.
• Choosing the correct FEM approach is vital for reliable biomechanical analysis in MOWHTO.