Crack propagation in articular cartilage under cyclic loading using cohesive finite element modeling

Area of Science:

• Biomechanics
• Materials Science
• Orthopedics

Background:

• Joint injuries can lead to cartilage defects that worsen with mechanical loading, potentially causing post-traumatic osteoarthritis (PTOA).
• Current understanding of cartilage crack propagation mechanisms is limited.
• Predictive numerical methods for cartilage crack growth under cyclic loading are lacking.

Purpose of the Study:

• To develop and validate a numerical cohesive damage model for estimating crack propagation in articular cartilage under cyclic loading.
• To investigate the influence of different cartilage material models, including fibril-reinforced poro-hyperelastic (FRPHE) models with varying collagen orientations, on crack propagation predictions.

Main Methods:

• Implementation of a numerical cohesive damage model for articular cartilage.
• Simulation of crack propagation under cyclic loading using four material models: hyperelastic, poro-hyperelastic, poro-hyper-viscoelastic, and FRPHE.
• Comparison of model predictions with experimental crack length data from literature.

Main Results:

• The cohesive damage model successfully replicated experimental crack lengths, demonstrating increased crack growth with more loading cycles.
• Calculated damage initiation stress and fracture energy values for several models aligned with previously reported ranges.
• FRPHE models highlighted the impact of the fibrillar matrix's anisotropy on cartilage behavior during crack propagation.

Conclusions:

• The developed cohesive damage model shows potential for estimating crack propagation in injured soft tissues like cartilage.
• This approach could provide crucial insights into adverse biomechanical scenarios in conditions such as osteochondral lesions, meniscal tears, and ligament ruptures.