Finite-Element Analysis of Bone Stresses on Primary Impact in a Large-Animal Model: The Distal End of the Equine Third Metacarpal.
Authors: McCarty Cristin A, Thomason Jeffrey J, Gordon Karen D, Burkhart Timothy A, Milner Jaques S, Holdsworth David W
Journal: PloS one
Summary
# Editorial Summary Researchers used advanced computational modelling to map bone stress distribution in the equine third metacarpal bone during the initial impact phase of landing, comparing a healthy joint against one with established osteoarthritis to understand whether ground contact generates the same patterns of stress concentration seen during the sustained weight-bearing of midstance. The team developed subject-specific, three-dimensional finite-element models based on detailed imaging data, allowing them to simulate the transient (very brief) mechanical forces occurring at foot strike and examine how these stresses differ between healthy and degenerative joints. Impact loading produced substantially higher stress concentrations in the subchondral bone than midstance loading—a finding of particular significance because high-stress zones aligned closely with the anatomical sites most commonly affected by mechanically induced osteoarthritis, particularly in the medial and lateral aspects of the distal metacarpal. For equine professionals involved in performance management and rehabilitation, these results suggest that the landing phase itself may represent a critical window for injury development, indicating that gait analysis, conditioning protocols and farriery interventions aimed at reducing impact forces during the first moments of weight acceptance could be more protective than previously recognised.
Read the full abstract on PubMed
Practical Takeaways
- •Impact forces at foot-strike create significant bone stresses that may contribute to OA development independently of midstance loading—consider impact management strategies in preventative care
- •Stress concentration sites identified in this model align with clinically observed OA locations, supporting biomechanical basis for common joint damage patterns
- •Surface and gait modifications that reduce impact shock may be as important as managing stance-phase loading in preventing degenerative joint disease
Key Findings
- •Peak stresses during foot impact at initial contact were comparable to or exceeded midstance loading stresses in the equine third metacarpal
- •High-stress zones during impact correlated with sites of naturally occurring osteoarthritic lesions in the affected joint
- •Subchondral bone experienced transient but substantial stress concentrations at ground contact, independent of midstance loading patterns