Osteoarthritis is the natural wear and tear of the articular cartilage of joints. When we are born we have smooth gliding articulating cartilage at the knee joints. Over time, the surface wears down and the cartilage degenerates. Thus the main causes of osteoarthritis are genetic predisposition to arthritis, obesity, high-impact activity, and trauma. Genetics are an uncontrollable factor in our lives. Some people are more at risk for early arthritis than others no matter what they do. Being obese definitely places undue stresses on a joint. Studies have shown that every 1 pound of weight loss reduce the amount of forces transmitted through the knee joint by 4 times! Thus even a limited weight loss program could reduce that force to make a person asymptomatic.
High impact activities such as running on hard pavement increase the amount of wear on joints. Activity modification to lower impact sports such as bicycling or swimming or even reducing the number of miles jogged per week can improve symptoms. Trauma is another uncontrollable factor for osteoarthritis. If you have a trauma such as a car accident or a fall that affects the joints, the chances of post-traumatic arthritis down the road are increased. Cartilage is relatively avascular and after injury it repairs very poorly. Even a crack in the cartilage will heal with fibrous tissue called fibrocartilage that has no where near the smoothness and gliding capabilities as native articular cartilage.
When the cartilage degenerates significantly, the joint becomes incongruent. What this means is that one side of the knee joint does not exactly match the other side. The joint actually "subluxates" during movement which causes friction in the joint and slight dislocation of the joint. This subluxation exacerbates the inflammation in the knee. Thus bracing helps to stabilize the joint in proper alignment to prevent subluxation. If arthritis affects one side of the knee more than other, special braces can also help unload the affected side to relieve pressure on the knee. |
