Articular (hyaline) cartilage is the smooth, tough, white cartilage that covers the end of bones when they come together to form joints. The smooth cartilage allows joints to glide smoothly without catching. When the cartilage is lubricated with joint (synovial) fluid the friction between the bone ends is negligible. The cartilage itself has no nerve or blood supply, relying on the surrounding joint fluid and underlying bone for nutrition.
Articular cartilage may become damaged by trauma or may become worn over time. Because of the lack of blood supply the cartilage has poor healing properties. This may lead to roughening of the joint surface and decline in joint function. Occasionally, the underlying bone may become exposed, triggering painful arthritis symptoms within the joint.
The symptoms of articular cartilage damage depend upon the site and size of the injury. Small areas of cartilage loss may be completely asymptomatic. As the injured area becomes more extensive it is common for patients to develop catching or locking symptoms. If bone becomes exposed below the cartilage then the joint often becomes painful. If large areas of bone are exposed then osteoarthritis symptoms develop with pain, stiffness and swelling of the joint.
The treatment for articular cartilage damage depends upon the symptoms and size of the problem. If conservative treatment has not helped then different surgical options may be considered.
Smaller, more localised areas of injury may be helped with restorative procedures to try and regenerate new cartilage to fill the damaged area. These types of procedures tend to work better in younger patients with more acute injuries. Large areas of injury and areas of arthritis are less likely to benefit from this type of surgery. Often this type of surgery can be performed arthroscopically or through small incisions around the joint.
The more common procedures for cartilage restoration include:
More extensive areas of cartilage loss, especially with areas of bone rubbing against bone, are not amenable to cartilage regeneration surgery. Joint replacement surgery may often be required in this situation. This may involve either partial or total joint replacement with metal, plastic or ceramic components.