When a patient is diagnosed with articular cartilage damage, or a defect, it is important to address the injury and treat the condition so that further progression does not occur. Articular cartilage is a very important component of a healthy knee joint. It is a fibrous substance that covers the ends of the bones and is what allows for a fluid, smooth, painless motion of the knee. When a patient has articular cartilage damage, either from a previous injury, overuse, or trauma to the knee, they will experience pain, swelling, and periods of weakness in the knee. Over time, this process will continue to progress and eventually lead to a complete loss of cartilage down to the bone. When this happens, a diseases known as osteoarthritis becomes present. This continues to cause progressive symptoms of knee pain and stiffness.​