What are knee cartilage lesions?
Cartilage allows the bones in the joints to glide so that they can move smoothly. A lesion is damage to that cartilage tissue. A lesion in the knee cartilage creates friction in the joint, which causes pain. In some cases, a knee cartilage lesion can lead to arthritis.
What are the signs and symptoms?
Articular cartilage lesions do not always cause symptoms. Just because there is no pain does not mean the lesion is not causing problems. In general, partially torn lesions do not heal by themselves, and they often get worse over time. Damaged cartilage can lead to short-term symptoms such as pain, swelling, locking symptoms, and longer-term symptoms of osteoarthritis due to lack of the shock absorber function. In many cases, associated pain is in a very specific location that corresponds to the site of the cartilage injury.
What are the causes?
Cartilage can become damaged due to a trauma such as a pivoting sport or when turning the knee or bending it deeply. Cartilage can also come loose due to damage in the underlying bone, and sometimes cartilage damage occurs as part of degeneration, called osteoarthritis, which is the overall loss of tissue quality that occurs with aging. Articular cartilage injuries in athletes are common among sports associated with cutting, jumping, pivoting, rapid deceleration and rapid acceleration. This is particularly true of football, basketball, and handball. Although cartilage lesions may occur in isolation, they are also frequently associated with other problems such as ligament (ACL tears) and meniscus injuries.
How is it diagnosed?
Evaluation of the athlete should include a combination of clinical history, detailed physical examination, and imaging. A cartilage defect is difficult to diagnose based on the history and physical examination alone and is sometimes mistaken for a meniscus lesion. An x-ray should be performed first to determine whether there are issues relating to malalignment and degenerative changes of the knee joint. However, this will not provide direct information on the status of the articular cartilage therefore an MRI will provide a non-invasive visualisation of this.
How is it treated?
Treatment begins with avoiding activity that causes pain, using crutches to offload the affected knee, keeping the knee moving to avoid stiffness and locking, and icing the knee. For surgery to be seriously considered, the athlete’s symptoms should be consistent with a full-thickness cartilage defect. When non-operative techniques of load regulation, rehabilitation, supportive or regenerative injections fail to achieve acceptable results and the level of play remains adversely affected, surgical intervention is needed, followed by physical therapy.
How can it be prevented?
Damage to the knee can be prevented or limited through regular exercise of varying impact, maintaining a healthy weight, and following preventative programs for other sports injuries such as ACL.