Knee Cartilage Injuries
Articular knee cartilage is the smooth white outer protective covering on the ends of our bones. Healthy cartilage in our joints makes it easier to move and allows the bones to glide over each other with very little friction. It also helps cushion the bones, absorbs shock, and distributes weight within our joints. Healthy cartilage is essential to proper knee function. Articular cartilage can be damaged by injury or normal wear and tear. When damaged or worn out, the bones rub together and we end up with “bone on bone.” Articular cartilage is a highly specialized structure with little potential to regenerate. Surgical techniques to repair damaged cartilage are still evolving. Most surgical procedures are focused on techniques to try and stimulate the growth of new hyaline cartilage.
Localized damage to the articular cartilage is called a cartilage defect. Cartilage defects are common injuries generally affecting people ages 15 to 30, and over age 50. Defects alter the normal distribution of weight bearing forces, cause substantial pain, compromise knee function, and predispose the patient to the development of degenerative joint disease.
What causes a chondral defect?
A cartilage defect can result from trauma such as a direct blow to the knee, a fall, a tackle, a sudden change of direction or a pivot. Cartilage defects can also develop over time due to wear and tear with age. This is called osteoarthritis, a degenerative joint disease.
Knee cartilage injuries can range from minor to severe, and they can often lead to long-term pain and disability. They can occur at the same time as a ligament injury such as an ACL tear or a meniscus tear.
What are the symptoms of a cartilage defect?
Symptoms of knee cartilage injuries include:
- Pain: You may feel pain in the knee joint itself or in the surrounding muscles and tissues. The pain may be sharp or dull, and it may be worse when you move your knee or put weight on it.
- Swelling: You may notice that your knee is swollen, particularly if the injury is to the meniscus (the C-shaped piece of cartilage that sits between the bones in the knee joint).
- Stiffness: Your knee may feel stiff and difficult to move.
- Locking: In some cases, the knee joint may “lock” or “catch” when you try to straighten it. This can be a sign of a meniscus tear or loose pieces of cartilage floating in the joint.
- Painful limping
How is a cartilage defect diagnosed?
Dr. Harrison will ask about your symptoms and how the injury occurred. He will review your medical history and ask about your goals and expectations from treatment. Then he will perform a physical examination testing knee mobility, stability, and your gait. Because symptoms of a cartilage defect are the same as symptoms of many other knee conditions, he may order imaging studies including x-rays to evaluate the bone, and an MRI, to evaluate the soft tissue to diagnose your knee cartilage injury.
What are the treatments for cartilage defects?
Treatment for a knee cartilage injury will depend on the size, location and severity of the injury, your age, BMI, and activity level, and whether there are other associated injuries.
For minor injuries, nonoperative measures including rest, ice, and over-the-counter pain medications, physical therapy, and lifestyle modifications to deal with pain and inflammation may be all that is needed. In addition, steroid or hyaluronic acid injections or platelet rich plasma injections may provide relief from pain and early knee arthritis. Nonoperative measures should be tried before invasive methods, when possible.
Arthroscopic debridement is a minimally invasive procedure performed using an arthroscope (a small camera inserted into the joint through a small incision). Dr. Harrison will remove any loose or damaged cartilage from the joint. This should eliminate pain and catching and locking.
Microfracture is a surgical technique that is used to treat small chondral defects. In this procedure, the surgeon makes very small fractures in the bone around the defect. This stimulates the stem cells in the bone marrow to produce new cartilage cells, which can help to repair the damage. It is a safe and effective procedure. Microfracture may be paired with cartilage augmentation.
Autologous chondrocyte implantation (ACI) is a two-step surgical technique that is used to treat larger chondral defects. In this procedure, the surgeon removes a small amount of healthy cartilage, about the size of two Tic Tacs, from another area of the knee. The cartilage cells are then isolated in the laboratory and multiplied. Once there is a sufficient number of cells, they are sent back to Dr. Harrison who transplants them back into your knee.
Membrane-induced autologous chondrocyte implantation (MACI) is a two-step procedure. First the cartilage cells are harvested from the knee and sent to a lab where they are grown on a collagen membrane. The membrane with the new cells is then implanted into the knee.
Osteochondral autograph transplant (OATS) is a procedure used to treat very large defects. It involves taking a healthy piece of cartilage and bone from another area of the body and transplanting it into the injury site to fill in the defect.
In some cases, joint replacement may be necessary when the cartilage is worn away and bone on bone pain is severe.
If you have an injury and knee symptoms, it’s important to get a proper diagnosis and treatment. There are many options available to treat cartilage defects and restore function. Contact Dr. Harrison to schedule a consultation and learn more about your condition and all your treatment options.
Dr. Harrison is a board-certified fellowship trained orthopedic and sports medicine surgeon who specializes in arthroscopic knee and shoulder surgery. He is the Head Team Physician for the United States Alpine Ski Team and the Head Team Physician for Weber State University for over 20 years. Dr. Harrison completed his undergraduate degree at Baylor University and received his medical degree from the University of Arizona College of Medicine. He completed his orthopedic residency at the University of Utah followed by a fellowship in sports medicine at the Cincinnati Sports Medicine and Orthopedic Center. He finished his formal training with an additional AO Trauma Fellowship in Bern, Switzerland.
At a Glance
Dr. Jeffrey Harrison
- Board-Certified, Fellowship-Trained Orthopedic Surgeon
- Head Team Physician US Women's Alpine Team and Weber State University
- Performs over 800 surgeries per year
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