Microcracks in subchondral bone plate is linked to less cartilage damage

Area of Science:

• Orthopedics
• Biomaterials Science
• Cell Biology

Background:

• Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage loss and subchondral bone changes.
• The precise role of microcracks in cartilage integrity and subchondral bone homeostasis remains unclear.
• Understanding microcracks is crucial for developing effective OA treatments.

Purpose of the Study:

• To evaluate microcrack density in human calcified cartilage and subchondral bone plate.
• To correlate microcrack density with the extent of cartilage damage in OA.
• To investigate the association between microcracks and osteocyte density in the subchondral bone.

Main Methods:

• Analysis of 18 human cadaveric knee bone cores.
• Quantification of microcrack density, osteocyte density, and cartilage damage using basic fuchsin staining.
• Confirmation of microcracks via scanning electron microscopy.
• Assessment of subchondral bone parameters using micro-CT.

Main Results:

• Microcracks were identified in both calcified cartilage and subchondral bone plate.
• Higher microcrack density in calcified cartilage and subchondral bone plate correlated with less cartilage damage (r = -0.45, p < 0.05).
• Microcracks in the subchondral bone plate were associated with lower histological OA scores.
• Osteocyte density in the subchondral bone plate increased with the presence of calcified cartilage microcracks.

Conclusions:

• Microcracks in the subchondral bone plate may be essential for maintaining cartilage homeostasis.
• Microcracks in calcified cartilage might stimulate osteocyte density, subsequently regulating subchondral bone remodeling to mitigate cartilage damage.