Cartilage is a resilient, flexible connective tissue. Its primary role in joints is to cover the ends of bones, providing a smooth, lubricated surface for fluid movement. This tissue also acts as a cushion, absorbing shock and distributing forces. Cartilage erosion is the progressive deterioration of this protective layer. As it thins, the underlying bone becomes exposed, leading to symptoms and functional limitations.
Causes of Cartilage Damage
The breakdown of joint cartilage can be initiated by several processes. A primary cause is osteoarthritis, a degenerative “wear and tear” condition. With this condition, the cartilage gradually roughens and thins from mechanical stress and the body’s reduced ability to repair itself with age, leading to pain and stiffness.
Inflammatory arthritis, such as rheumatoid arthritis, is another significant cause of cartilage damage. Unlike the mechanical nature of osteoarthritis, rheumatoid arthritis is an autoimmune disorder where the immune system attacks the synovium, the lining of the joints. This chronic inflammation releases enzymes that degrade the adjacent cartilage over time.
Direct trauma from a fall, sports injury, or accident can lead to post-traumatic arthritis. A severe impact can tear or fracture the cartilage, disrupting the joint’s mechanics and accelerating the degenerative process. Factors like obesity, which increases the load on weight-bearing joints, and genetics can also predispose individuals to earlier cartilage erosion.
Signs and Symptoms
The most common complaint of cartilage erosion is joint pain that worsens during or after movement and may be relieved by rest. As the condition advances, pain can become more constant. This is often accompanied by joint stiffness, particularly in the morning or after a period of inactivity.
In addition to pain and stiffness, many individuals experience swelling in the affected joint, which can feel warm and tender to the touch. A reduced range of motion is another frequent symptom, making it difficult to bend or straighten the joint fully as the damage progresses.
A sensation known as crepitus may also be present, which is a grating or popping sound within the joint during movement. It is caused by irregular, damaged cartilage surfaces rubbing against each other. While cartilage erosion can occur in any joint, it most commonly affects high-impact joints like the knees and hips, as well as the small joints of the hands and the spine.
Medical Diagnosis Process
A diagnosis of cartilage erosion begins with a patient history and a physical examination. During the exam, a doctor will assess the affected joint for tenderness, swelling, and warmth. They will also test its range of motion to identify limitations or pain triggered by specific movements.
If cartilage damage is suspected, imaging tests are the next step. An X-ray is often the first test used. While X-rays do not show cartilage, they can reveal indirect signs of erosion, such as a narrowing of the space between bones. They can also identify bone spurs, which are bony growths that develop in response to cartilage breakdown.
For a more definitive assessment, a magnetic resonance imaging (MRI) scan may be ordered. An MRI creates detailed images of both hard and soft tissues, allowing the doctor to directly see the cartilage and evaluate its thickness and integrity. This can detect tears or wear not visible on an X-ray. In some cases, a procedure called arthroscopy might be used to directly inspect the cartilage with a small camera.
Management and Treatment Approaches
The approach to managing cartilage erosion is tailored to the individual’s age, activity level, and severity of damage. Treatment begins with conservative, non-surgical methods. Lifestyle modifications include weight management to reduce stress on weight-bearing joints and low-impact exercises like swimming to strengthen muscles that support the joint. Physical therapy helps develop a targeted exercise program to improve flexibility and strength.
To manage pain and inflammation, over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended. If these are not sufficient, a doctor may prescribe stronger medications. These oral medications help alleviate symptoms that limit daily activities.
For more targeted relief, injections directly into the joint may be considered. Corticosteroid injections can provide a short-term reduction of inflammation and pain. Another option is hyaluronic acid injections, a therapy that injects a gel-like substance into the joint to supplement the natural fluid, which may improve lubrication.
When conservative treatments no longer provide relief, surgical options may be explored. Arthroscopy is a minimally invasive procedure where a surgeon can smooth damaged cartilage or remove loose fragments. For more extensive damage, a surgeon might perform procedures to stimulate new cartilage growth, such as microfracture. In end-stage cases, a total joint replacement replaces the damaged joint with a prosthesis to restore function and eliminate pain.