Composition, architecture and biomechanical properties of articular cartilage in differently loaded areas of the equine stifle.
Authors: Fugazzola Maria, Nissinen Mikko T, Jäntti Jiri, Tuppurainen Juuso, Plomp Saskia, Te Moller Nikae, Mäkelä Janne T A, van Weeren Rene
Journal: Equine veterinary journal
Summary
# Equine Stifle Cartilage: Why One Size Doesn't Fit All in Repair The stifle's articular cartilage is not biochemically uniform—a finding with profound implications for how we approach cartilage injuries and repair strategies. Fugazzola and colleagues examined osteochondral samples from three functionally distinct regions of the equine stifle (the lateral trochlear ridge and medial femoral condyle as weight-bearing surfaces, versus the intercondylar notch as a non-weight-bearing area), characterising their composition, architecture and mechanical properties using biochemical assays, biomechanical testing and structural analysis. The results revealed marked site-specific differences: the medial femoral condyle contained the highest glycosaminoglycan content (93.7 µg/mg dry weight), whilst the intercondylar notch had substantially lower levels (37.3 µg/mg), and these proteoglycan differences correlated strongly with the cartilage's ability to resist compression (equilibrium modulus: r = 0.642). Collagen orientation similarly varied between sites, with non-weight-bearing cartilage displaying more randomly oriented fibres and lower stiffness properties. For practitioners designing or selecting cartilage repair interventions—whether arthroscopic debridement, biological scaffolds or cell-based therapies—these findings underscore the importance of tailoring treatment to the specific biomechanical demands of the affected region, rather than applying standardised protocols across all stifle lesions.
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Practical Takeaways
- •Cartilage repair strategies must account for significant topographical differences in composition, architecture, and mechanical properties between weightbearing and non-weightbearing areas of the equine stifle to achieve durable functional outcomes
- •The lateral trochlear ridge and medial femoral condyle respond differently to load than the intercondylar notch, suggesting site-specific repair approaches may be necessary
- •Understanding the relationship between tissue composition (proteoglycans and collagen) and mechanical function is critical when selecting or designing cartilage repair treatments for different stifle regions
Key Findings
- •Glycosaminoglycan content differed significantly between three stifle sites: LTR 75.4, ICN 37.3, and MFC 93.7 μg/mg dry weight
- •Equilibrium modulus was highest at weightbearing sites (LTR 2.20 MPa, MFC 1.36 MPa) compared to non-weightbearing ICN (0.48 MPa)
- •Collagen content was higher in non-weightbearing ICN (176 μg/mg) versus weightbearing areas LTR (139 μg/mg) and MFC (127 μg/mg)
- •Proteoglycan content showed strongest correlations with equilibrium modulus (r=0.642) and dynamic modulus (r=0.554); collagen orientation angle correlated with equilibrium modulus (r=-0.612)