Cartilage Defects (Lesions)
Articular cartilage is smooth white tissue (hyaline cartilage) that covers the ends of the bones where they meet to form a joint. If functions to provide a smooth surface for the bones in a joint to articulate and to distribute weight to reduce friction. Cartilage has no blood supply or nerves and has a limited ability for self-healing and repair, which makes treatment of cartilage defects difficult. Preservation of articular cartilage is the key to joint health. Injury to the articular cartilage is a significant cause of musculoskeletal dysfunction.
What is a cartilage (chondral) defect?
A cartilage defect is localized (focal) damage to the articular cartilage that lines the ends of the bones. Focal chondral defects are graded by severity. Grade I is the mildest and grade IV (exposed bone) is the most severe.
What causes a chondral defect?
Typically, a chondral defect results from an acute injury like a sudden pivot or twist of the knee, a fall or direct blow to the knee. Repetitive motions can cause minor damage that accumulates and becomes painful and debilitating over time. A defect can also occur in combination with other knee injuries such as a ligament injury or damage to the meniscus in the knee.
A chondral lesion is a common injury affecting 5-10% of people over age 40, but it can also affect young patients that experience traumatic injuries. Damage to knee cartilage can lead to post-traumatic osteoarthritis of the knee over time. Normal wear and tear on the joint can cause the cartilage to break down, thereby leading to pain and disability as well as osteoarthritis.
What are the symptoms?
A focal injury to the cartilage may cause pain, intermittent swelling, and a grinding sensation. The injury may cause cartilage fragments to float in the joint causing locking, catching and swelling.
How is chondral injury diagnosed?
Dr. Jonathan Godin will review your medical history, ask questions about the events surrounding your injuries and activities that cause you pain. His focus is on helping you to heal so that you can return to sports and activities that make life enjoyable. Therefore, he will listen to your concerns and goals to help guide your treatment.
Chondral defects are difficult to diagnose because symptoms may not appear immediately, and when other damage is present a chondral lesion may not be as apparent as the other damage. Moreover, damage to hyaline cartilage does not show on an x-ray.
Dr. Godin will conduct a comprehensive physical examination involving range of motion, stability, and gait. However, physical exam alone may not reveal the damage. X-rays will assess arthritis, bony defects, and misalignment. MRI imaging is helpful for evaluating the chondral surfaces. However, the most reliable diagnostic procedure is knee arthroscopy which allows him to see inside the joint to evaluate the damage.
How is a chondral defect treated?
The choice of treatment will depend on the size of the defect, its location, and the patient’s goals. Chondral defects are difficult to treat and can sometimes require surgical repair if all conservative measures have failed.
When the symptoms are mild, the first line treatment is nonoperative, including anti-inflammatory medications, icing, activity modification and physical therapy. Corticosteroid, hyaluronic acid, or platelet-rich plasma injections and bracing may be recommended. In addition, protective supplements of glucosamine and chondroitin may be recommended in specific cases. All of these treatments will provide symptomatic relief but will not heal a defect.
The choice of procedure depends upon the patient’s age and weight, and their activity goals; and on the size and location of the defect. Cartilage restoration is the goal. Surgery is aimed at restoring the articular surface. It is not used in cases of wear and tear chondral defects.
- Arthroscopic debridement is a procedure to remove cartilage fragments in the joint to relieve symptoms.
- Arthroscopic microfracture is a procedure to stimulate the creation of new cartilage-like tissue called fibrocartilage. This fibrocartilage can provide functional improvement, but it is not as long-lasting as the original articular cartilage.
- Osteochondral autograft of cartilage and bone is a procedure where healthy cartilage is harvested from one part of your knee and transplanted into the defect.
- Osteochondral allografts of donor cartilage can be implanted into the lesion. Survival rates have been reported to be excellent even at 10 years.
- Autologous chondrocyte implantation is a procedure where your own cartilage cells are harvested, grown in a lab and implanted into the defect. This is a two-stage cell-based procedure, because it requires an initial arthroscopic procedure to harvest the cells (small biopsy from your cartilage). The patient’s own cartilage cells (chondrocytes) are harvested from a non-weight bearing joint and grown (cultured) in a lab over several weeks. The lesion is also debrided to remove damaged cartilage at this initial procedure. When ready, the cultured cells are implanted into a membrane which will then cover the cartilage defect. Because the transplants are made of the patient’s own cells, there is no risk of rejection. MACI is best for younger patients that want to remain active and can commit to post-op rehabilitation. It is most commonly used for patellofemoral (knee cap) cartilage injuries.
Dr. Jonathan Godin is a board-certified orthopedic surgeon at the world-class Steadman Clinic is Vail, Colorado. He specializes in the treatment of complex knee, hip, and shoulder injuries and conditions, and sports medicine. One of his areas of expertise is joint preservation and cartilage restoration techniques. Contact Dr. Godin to schedule a consultation for yourself or someone you love.