Subchondral Sclerosis: Causes, Symptoms, and Treatment

Medically Reviewed by Tyler Wheeler, MD on August 28, 2022
2 min read

Subchondral sclerosis is a thickening of bone that happens in joints affected by osteoarthritis. If you’ve been diagnosed with osteoarthritis or have early symptoms of osteoarthritis, your doctor may mention subchondral sclerosis as one sign of the disease.

“Subchondral bone” is bone that sits underneath cartilage in a joint. Subchondral bone is found in large joints like the knees and hips, as well as in small joints like those of the hands and feet.

“Sclerosis” refers to an unusual increase in the density or hardness of a tissue in the body. In the case of bone, sclerosis means that an area of bone is making more new bone tissue than usual and becoming denser and thicker. So subchondral sclerosis is a thickening and hardening of bone that happens underneath cartilage in a joint.

While bone sclerosis in general can be related to other conditions, sclerosis of the subchondral bone in joints is linked to osteoarthritis.

Some studies show that subchondral sclerosis can happen before osteoarthritis damages joint cartilage. This raises the question of whether subchondral sclerosis actually causes, in part, the disease. Researchers are studying this, and some have found that subchondral sclerosis is more common in later stages of osteoarthritis.

Doctors can diagnose osteoarthritis without any signs of subchondral sclerosis. But when it’s present, the thickening of bone can help them diagnose osteoarthritis. Other conditions that have similar symptoms to osteoarthritis, such as rheumatoid arthritis, don’t lead to subchrondral sclerosis.

The symptoms of subchondral sclerosis are similar to the most common ones from osteoarthritis, such as:

  • Pain and tenderness in affected joints -- most often the hands, knees, hips, and spine
  • Stiffness and loss of flexibility in joints
  • A grating feeling in the joint
  • Hard lumps, or bone spurs, in the bones around the affected joints

The changes in bone linked to subchondral sclerosis show up on MRI and X-ray scans. The subchondral sclerosis appears as a bright, dense area of bone on the scans.

There are no treatments specifically for subchondral sclerosis, but there are for osteoarthritis.

Some surgical treatments for advanced osteoarthritis, including joint replacement surgery or an osteotomy in which an area of bone is removed, may lead to the removal of bone affected by subchondral sclerosis.