Validation of a personalized ligament-constraining discrete element framework for computing ankle joint contact...

Area of Science:

• Biomechanics
• Computational modeling
• Orthopedics

Background:

• Articular ankle pathology understanding benefits from joint contact mechanics simulations.
• Discrete element analysis (DEA) offers computational simplicity over finite element analysis (FEA).
• Previous DEA models lacked subject-specific anatomy and oversimplified ankle biomechanics.

Purpose of the Study:

• To develop and validate a personalized DEA framework for ankle joint biomechanics.
• Incorporate subject-specific cartilage thickness and ligamentous constraints.
• Enable fibula movement within the ankle mortise.

Main Methods:

• Developed linear and non-linear DEA models with cartilage represented as springs.
• Constructed 3D ankle models from CT scans, incorporating personalized cartilage thickness and ligament insertion sites.
• Validated contact stress prediction against FEA and ankle mortise position against cadaveric data.

Main Results:

• DEA models predicted mean articular contact stress within 0.36-0.39 MPa of FEA.
• The DEA ligament-balancing algorithm reproduced distal fibula position within 0.97 mm of experimental data.
• The combined DEA model predicted mean articular contact stress within 0.50 MPa of FEA.

Conclusions:

• The personalized DEA framework is a computationally efficient alternative to FEA for ankle joint analysis.
• This model enhances understanding of articular ankle pathologies at patient-specific and population levels.
• Novelty lies in personalization, distal tibiofibular joint inclusion, and non-linear ligament balancing for physiological articulation.