What Is Subchondral Sclerosis?

Doctor looking at hip x-ray.
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Subchondral sclerosis is a thickening of the bone in joints. It can affect people who have osteoarthritis and result in painful bone spurs. Fortunately, subchondral sclerosis is easily detected and there are several treatment options available.

To understand what subchondral sclerosis is, it is helpful to have a clear picture of how osteoarthritis affects the joints of the body.

Not only does osteoarthritis degrade the cartilage in a joint, it also wears away at the subchondral bone underneath the cartilage. As the body tries to regrow this bone, it comes back thicker than before, resulting in subchondral sclerosis. It is most commonly detected in later stages of osteoarthritis. Subchondral sclerosis can cause bone spurs, and in some cases, can reduce motion in the affected joint. 

Detection of Subchondral Sclerosis

When you have an X-ray as part of the diagnostic process for osteoarthritis, subchondral sclerosis is one of the things the radiologist looks for and observes. It shows up on X-ray as a denser area of bone just under the cartilage in your joint, appearing as abnormally white bone along the joint line. Subchondral sclerosis is seen in osteoarthritis in many of the commonly affected joints, such as the knee, hip, spine, and foot. 

Subchondral Sclerosis in Osteoarthritis

Subchondral sclerosis does not usually predict how osteoarthritis will progress.

You should not assume that your osteoarthritis is worsening if you are diagnosed with subchondral sclerosis.

A study published in 2014 considered whether subchondral sclerosis that was detected by magnetic resonance imaging (MRI) was associated with loss of cartilage. Researchers enlisted 163 people with knee pain and followed them for three years with baseline knee X-rays and MRI examinations.

They found no significant associations between baseline subchondral sclerosis and increased risk of cartilage loss in the same region of the knee.

Another study, also published in 2014, examined whether subchondral sclerosis was actually protecting the knee from joint space narrowing in people with varus knee osteoarthritis. People with this condition have typically been referred to as "bow-legged" since it causes visible differences in the knee and leg. The researchers in this study looked at 192 women who had already been diagnosed with varus knee osteoarthritis and performed knee X-rays, as well as dual-energy X-ray absorptiometry (DEXA) at the lumbar spine, proximal femur, and knee condyles. The study concluded that the increase in subchondral bone sclerosis might protect against the decrease in cartilage thickness.

Subchondral Sclerosis Treatment

Much like osteoarthritis, there is no cure for subchondral sclerosis. But, there are steps you can take to slow its progression and reduce painful symptoms. Low-impact physical exercise, including using a stationary bike, yoga, and swimming are excellent ways to keep the affected joints active. In people who are overweight, losing weight is also recommended as a way to reduce stress on their joints.

Your doctor may also recommend physical therapy, hydrotherapy, or more holistic medical treatments, such as acupuncture. Anti-inflammatory medications, such as ibuprofen, also may be recommended. For more serious cases, there are prescription medications which may help to provide relief. In general, anything that relieves osteoarthritis symptoms will help subchondral sclerosis symptoms as well.

In some severe cases, surgery to remove the excess bone growth may be recommended. As with any chronic condition, consult with your doctor to determine the best course of treatment for your symptoms.

A Word From Verywell

Subchondral bone is more than an image on an X-ray.

It is involved with and is affected by what is happening with the cartilage in a joint. When cartilage is thinned in osteoarthritis, the bone reacts. You can keep your joints as healthy as they can be by low-impact exercise and physical therapy.

Sources:

Akamatsu Y, Kobayashi H, Kusayama Y, Kumagai K, Mitsugi N, Saito T. Does subchondral sclerosis protect progression of joint space narrowing in patients with varus knee osteoarthritis? Osteoarthritis and Cartilage. 2014;22. doi:10.1016/j.joca.2014.02.667.

Crema M, Cibere J, Sayre E, et al. The relationship between subchondral sclerosis detected with MRI and cartilage loss in a cohort of subjects with knee pain: the knee osteoarthritis progression (KOAP) study. Osteoarthritis and Cartilage. 2014;22(4):540-546. doi:10.1016/j.joca.2014.01.006.

Li G, Yin J, Gao J, et al. Subchondral bone in osteoarthritis: insight into risk factors and microstructural changes. Arthritis Research & Therapy. 2013;15(6):223. doi:10.1186/ar4405.