Friction sounds in the knee could require cartilage repair

If you experience pain, swelling and an audible clicking sound in your knee, whether active or at rest, you could have an articular cartilage injury. This tough and elastic material, similar to what makes up your ears and portions of your nose, covers the ends of the three bones in your knee joint. Known as hyaline cartilage, it helps the joint move smoothly and absorbs shock experienced when climbing stairs, walking, running or jumping. While this cartilage wears down as we age, it also can become damaged, due to traumatic injury, overuse, malalignment or muscle weakness.

Articular cartilage injuries are common in young adults — particularly cyclists, skiers, soccer players and runners. Individuals who are 50 or older and suffer from osteoarthritis also are susceptible. When damage occurs, cartilage takes a long time to heal because it is extravascular, which means that it does not have a blood supply. If cartilage damage is not addressed, it affects the healthy surface of the joint. This, in turn, can change the mechanics of the knee, leading to the feeling of instability and discomfort. Damage also can result in fractures to the bone below the cartilage (an osteochondral fracture). Based on symptoms and to confirm the diagnosis, an orthopedic doctor may order an X-ray, an MRI or perform an arthroscopy (insertion of a scope to examine and repair damage).

The most conservative treatment for articular cartilage injuries involves rest, ice, compression and elevation (RICE) hourly, for 10-to-15 minutes to reduce swelling, medication to reduce inflammation and exercise rehabilitation. When the injury is more serious and surgical intervention is necessary, the most common and popular procedure is microfracture surgery, during which the surgeon drills into the knee bone to encourage stem cells to heal the area with scar cartilage. Microfracture surgery often is viewed as the most popular because it enables athletes to return to activities quickly.

The second most common treatment is an osteochondral autograft transfer. This procedure allows the doctor to remove healthy cartilage from another area and implant it in the damaged area. Autologous cartilage implantation is another option for intervention that requires two surgeries: one arthroscopic procedure to biopsy the cartilage cells and then grow additional cells that are implanted during a second procedure. This option requires additional time for the cells to mature. The return to sports typically is delayed for about a year.

To avoid articular cartilage injuries, older patients are encouraged to maintain a mobile lifestyle, while individuals between the ages of 30 and 50 are encouraged to vary or modify their athletic activities to reduce repetitive use as well as high amounts of force on the knees. If you suspect a cartilage injury, schedule an appointment with your primary care doctor, or ask for a referral to an orthopedic surgeon.

— Campbell is an orthopedic surgeon specializing in sports medicine at UPMC Susquehanna. He earned his medical degree from Howard University College of Medicine and completed his residency with Howard University Hospital in Washington, D.C.

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