Osteoarthritis happens when the articular cartilage covering the bone ends become damaged and fail to glide smoothly.
The knee joint is one of the strongest and most important joints in the human body. The knee, also known as the tibiofemoral joint, is a hinge joint. It allows the lower leg to move and bend to support the body’s weight. The movements at the knee joint are essential to many everyday activities such as walking, running, sitting and standing.
The knee joint is comprised of three bones: the femur (thigh bone), tibia (shin bone), and patella (knee cap). The end of the femur rest on top of the tibia, allowing for the weight to be transferred across the knee. The joint-forming surfaces of each bone are covered with articular cartilage.
Articular cartilage is the tough but smooth covering on the end of bones in most joints. It allows gliding without much resistance and works with the meniscus to cushion the ends of the bone.
Over time, this articular cartilage loses its ability to heal itself and often can get injured or worn out. Osteoathritis happens when the articular cartilage covering the bone ends become damaged and the joint is unable to glide smoothly. Many factors contribute to this, but genetics, a past history of injury or surgery, and overuse seem to be the most important causes.
Treatment of articular cartilage injuries and osteoarthritis is dependent on the size as well as the extent of the damage. The first line of treatment is focused on reducing the inflammation associated with the loss of articular cartilage. Nonoperative interventions such as cold therapy, anti-inflammatory medications and injections play an important role in reducing the inflammation within the joint. Physical therapy is another treatment option that places emphasis on strengthening the muscles around the joint to help compensate for the injury.
Good pain relief and return of function can be seen with non-operative modalities. However, if these fail to improve the surgery can be an option. For small, focal loss of cartilage, arthroscopic procedures such as microfracture and chondroplasty can help the joint move smoother and even possibly repair itself. For cases of osteoarthritis to specific areas of the knee secondary to poor alignment and mechanics, realignment procedures such as osteotomies can help the correct deformities and alleviate pain. Once osteoarthritis and cartilage loss have progressed in severity to where there is not cartilage left, often referred to as “bone-on-bone”, arthroplasty or joint replacement surgery can play a very beneficial role.