Calcified cartilage morphometry and its relation to subchondral bone remodeling in equine arthrosis.

The study investigates the relationship between the subchondral bone remodeling and the morphometry of the calcified cartilage layer in the development of arthrosis. The researchers found that while subchondral remodeling can affect the calcified layer, the thickness and irregularity of the calcified cartilage are not consistently related to the remodeling process.

Research Background

• Arthrosis is a degenerative disease that affects the joints, commonly causing discomfort and pain.
• The calcified layer of articular cartilage is known to be influenced by age and mechanical factors. Both are also associated with subchondral remodeling and sclerosis, processes involved in the development of arthrosis.

Research Methodology

• The research conducted a morphometric study on fluorochrome-labeled animals to establish whether the level of subchondral remodeling influences the thickness, irregularity and vascularity of the calcified cartilage layer at the interface with subchondral bone.
• This study also focused on a site of increased mechanical stress. The calcified cartilage layer’s area and thickness were determined in basic fuchsin-stained ground sections.
• The irregularity of the chondro-osseous interface was calculated as the ratio of its length to the relatively straight tidemark, and the quantity of abutting vessels with and without fluochrome labels were counted.

Results and Findings

• The study found a correlation between an increase in percent vascularity at the interface and the index of remodeling in subchondral bone. However, the number of abutting vessels and the interface irregularity did not significantly change on the fragmented side.
• There was no significant differences found in the metacarpal condyles from the fetlock joints of the same horses with a surgically created fragment in the carpus.
• In sites of mechanical overload, the calcified cartilage was thinner, and the interface irregularity was higher, suggesting previous increased remodeling.
• Overall, the research found that subchondral remodeling can influence the calcified layer, but the thickness and irregularity of the calcified cartilage are not consistently related to current subchondral remodeling processes.

Conclusion

• The findings indicate that while activated subchondral remodeling extends to involve the calcified layer, the thickness and irregularity of the calcified cartilage do not have a consistent relationship with current subchondral remodeling.
• This suggests that at sites of mechanical overload where the cartilage is potentially more fragile, earlier increased remodeling could have occurred.