Subchondral bone in osteoarthritis: insight into risk factors and microstructural changes

Area of Science:

• Orthopedics
• Rheumatology
• Bone Biology

Background:

• Osteoarthritis (OA) is a leading cause of adult disability, characterized by cartilage degradation and joint structure changes.
• Traditionally viewed as a cartilage disorder, OA pathogenesis increasingly implicates subchondral bone.
• Subchondral bone alterations, including sclerosis and hypomineralization, are hallmarks of OA.

Purpose of the Study:

• To review the osteochondral junction's basic features.
• To discuss risk factors affecting subchondral bone integrity in OA.
• To explore subchondral bone's microarchitectural and histopathological changes in OA progression.

Main Methods:

• Literature review focusing on subchondral bone in osteoarthritis.
• Analysis of histopathological and microarchitectural changes.
• Synthesis of current understanding into a hypothetical OA pathogenesis model.

Main Results:

• Subchondral bone plays a critical role in OA pathogenesis.
• OA involves abnormal subchondral bone remodeling, leading to hypomineralization despite increased bone volume.
• Histopathological changes like microdamage and bone marrow lesions are observed in subchondral bone.

Conclusions:

• Subchondral bone integrity is crucial for OA progression.
• Understanding subchondral bone changes offers insights into OA pathogenesis.
• A hypothetical model is proposed to explain OA development involving subchondral bone.