Optimal hinge level in opening wedge high tibial osteotomy: Biomechanical analysis using finite element method

Area of Science:

• Orthopedic surgery
• Biomechanics
• Biomedical engineering

Background:

• Understanding the biomechanical environment at the lateral tibial cortex during opening wedge high tibial osteotomy (OWHTO) is crucial for minimizing hinge fractures.
• Previous research lacks detailed analysis of how hinge placement affects stress distribution on the lateral tibial cortex.

Purpose of the Study:

• To evaluate the impact of different hinge levels on the biomechanical environment at the lateral tibial cortex.
• To identify optimal hinge placement for reducing the risk of lateral tibial cortex fracture during OWHTO.

Main Methods:

• Development of heterogeneous finite element models based on CT images of patients undergoing OWHTO.
• Simulation of OWHTO with three distinct hinge levels (proximal, middle, distal) and varying correction angles.
• Calculation of maximum von Mises stress at the lateral tibial cortex for each simulated scenario.

Main Results:

• The middle hinge level resulted in the lowest maximum von Mises stress at the lateral tibial cortex.
• The distal hinge level exhibited the highest stress, indicating an increased fracture risk.
• Higher correction angles correlated with a greater likelihood of lateral tibial cortex fracture.

Conclusions:

• The optimal hinge level for OWHTO is at the superior aspect of the proximal tibiofibular joint's articular cartilage.
• This anatomical position is biomechanically advantageous as it is independent of the fibula, minimizing stress concentration and fracture risk.