A subchondral cancellous bone oedema describes a build-up of excess fluid in the bone directly beneath the joint cartilage. It often occurs as a reaction to mechanical overload, inflammation, or degenerative joint disease. On an MRI scan, the oedema appears as a bright signal change, which can indicate a disruption in blood supply or a stress response in the bone.
**How does a subchondral cancellous bone oedema develop?**
The bone structure beneath the joint cartilage, known as the subchondral cancellous bone, is sensitive to stress. When a joint is placed under excessive strain, tiny injuries can develop in the bone tissue. This causes fluid to collect, which shows up as a visible change on an MRI scan. A poor oxygen supply to the bone can also trigger this type of oedema. It is particularly common in osteoarthritis, when the joint cartilage is damaged and the bone layer beneath it takes on greater load.
**Possible causes and symptoms**
A subchondral cancellous bone oedema can be painful, especially when it occurs alongside joint inflammation or early-stage osteoarthritis. In many cases, it is a sign that the affected area has been placed under too much strain. Sports-related overuse, misalignment of the joint, or previous injuries can all contribute to its development. Inflammatory joint conditions such as rheumatoid arthritis or avascular bone necrosis are also frequently associated with this type of oedema.
**Diagnosis and medical significance**
Because the oedema cannot be seen on an X-ray, the diagnosis is usually made using an MRI scan. A careful assessment of the signal changes helps to identify the underlying cause. It is important to determine whether the oedema is reversible or whether progressive joint damage is to be expected. In some cases, it is a temporary finding that resolves once the joint is given adequate rest.
**Treatment and outlook**
Treatment depends on the cause of the oedema. In most cases, relieving pressure on the affected joint is the main priority in order to support the healing process. Physiotherapy and gentle, joint-friendly movement can help to distribute load more evenly. Anti-inflammatory medication or targeted injections may be used when pain is present. In severe cases, particularly where progressive cartilage damage is present, surgical treatment may be necessary. The outlook depends greatly on how early the underlying cause is identified and treated.
