The subchondral bone lies immediately under the cartilage in a joint. In osteoarthritis, as cartilage wears, load transfers to this bone; it responds by thickening (sclerosis), forming cysts and remodelling — all changes visible on X-ray. Painful subchondral bone-marrow lesions on MRI are increasingly recognised as a source of osteoarthritis pain and a target for research into new treatments.
What is subchondral bone?
Subchondral bone: Subchondral bone lies immediately beneath the joint cartilage. In OA, it thickens ('sclerosis'), may develop small holes ('cysts') and gets damaged as cartilage thins. Changes are visible on X-ray and are diagnostic.
Last updated 2026-07-04. This is general information, not a substitute for personalised medical advice.