Which change is associated with late-stage OA subchondral bone?

• A. Subchondral bone sclerosis and osteophyte formation
• B. Decreased bone turnover
• C. Poor bone mineralization
• D. Increased susceptibility to bone deformation

Answer: (A)

In late-stage osteoarthritis, the bone just under the damaged cartilage adapts to the abnormal joint mechanics by increasing remodeling that leads to thickening and densification—subchondral sclerosis. Along the joint margins, osteophytes or bone spurs form as the skeleton attempts to stabilize the joint and distribute loads more effectively. These two changes—subchondral sclerosis and osteophyte formation—are hallmark features of late OA subchondral bone, visible on imaging as a denser subchondral plate and bony outgrowths at the joint margins.

Other patterns don’t fit OA as well. Decreased bone turnover is more typical of osteoporosis, not the sclerosis seen in OA. Poor bone mineralization points to metabolic bone diseases like osteomalacia. And while OA can involve altered load and potential microdamage, the characteristic late-stage pattern emphasizes increased density and osteophyte development rather than greater bone fragility or deformability.