Evaluation of subchondral bone mineral density associated with articular cartilage structure and integrity in healthy equine joints with different functional demands.

The research article investigates the relationship between subchondral bone mineral density and the structure of the cartilage overlaying it in equine joints with varying functional demands, concluding that variations in cartilage and bone responses to physiological load can be site-dependent.

Methodology

• The study involved 8 healthy horses aged between 2 to 3 years.
• Osteochondral samples were acquired from two different locations; the medial femoral condyle and the medial trochlear ridge of the stifle joint, and the dorsal and palmar aspects of the distal medial third metacarpal condyles of the metacarpophalangeal joint.
• The structure and tensile biomechanical properties of the articular cartilage was assessed and the volumetric bone mineral density of the underlying subchondral plate was determined via dual-energy x-ray absorptiometry.

Results

• It was found that the tensile moduli, tensile strength and volumetric bone mineral density were higher, whereas the tensile strain at failure was lower in the dorsal and palmar locations as compared to the condyle and ridge locations.
• The tensile moduli of the cartilage positively correlated with the volumetric bone mineral density, whereas its staining and tensile strain at failure negatively correlated with the volumetric bone mineral density.

Conclusion

• The research concluded that areas of high joint loading had a high volumetric bone mineral density and the overlaying articular cartilage exhibited high tensile stiffness but showed signs of structural wear.
• The variations and relationships between the subchondral bone and articular cartilage noted in this study support the notion that both elements adapt to physiological load in a coordinated manner, and this can be site-dependent.