Efficient computation of cartilage contact pressures within dynamic simulations of movement

Abstract

The objective of this study was to assess the use of an advanced collision detection algorithm to simulate cartilage contact pressure patterns within dynamic musculoskeletal simulations of movement. We created a knee model that included articular cartilage contact for the tibiofemoral and patellofemoral joints. Knee mechanics were then predicted within the context of a dynamic gait simulation. At each time step of a simulation, ray casting was used in conjunction with hierarchical oriented bounding boxes (OBB) to rapidly identify regions of overlap between articulating cartilage surfaces. Local cartilage contact pressure was then computed using an elastic foundation model. Collision detection implemented in parallel on a GPU provided up to a 10× speed increase when using high-resolution mesh densities that had >10 triangles/mm². However, pressure magnitudes converged at considerably lower mesh densities (2.6 triangles/mm²) where CPU and GPU implementations of collision detection exhibited equivalent performance. Simulated tibiofemoral contact locations were comparable to prior experimental measurements, while pressure magnitudes were similar to those predicted by finite element models. We conclude the use of ray casting with hierarchical OBB for collision detection is a viable method for simulating joint contact mechanics in human movement.

Keywords:

• Joint contact
• collision detection
• elastic foundation
• musculoskeletal models
• multibody dynamics

Acknowledgements

We thank Rachel Lenhart, Jarred Kaiser and Anne Schmitz for their contributions to the development of the knee model and Radu Serban for his constructive feedback.

Funding

This work was supported by the National Institute of Child Health and Human Development [grant number HD08413]; National Institutes of Health [grant number EB015410]; National Science Foundation [grant number 0966535].