Osteoarthritis is a progressive, degeneration of articular cartilage. It affects 21 million Americans and their ranks are increasing as Americans get older and bigger.
It is not uncommon at this time to see patients in the office who are 100 to 150 pounds overweight.
For these patients arthritis is not just a worry of the future. America's growing weight problem has turned arthritis from an elderly person's complaint to a disease that affects many people in the prime of life.
The epidemic of arthritis has arrived and increasingly we see young and middle aged patients with joints that have started to seriously deteriorate.
The cartilage that we are talking about is not the wedge shaped cushion in the knee also referred to medically as meniscus. Patients commonly call the meniscus "cartilage" and if it is damaged, the term "torn cartilage" is well fixed in the minds of most patients.
The true cartilage in the knee is the covering over the end of bones, which is a very slippery, resilient tissue that keeps the joint moving smoothly and is actually designed to last a lifetime in most patients.
Unfortunately, injuries to the knee can cause wear and tear changes in the knee which result in this true cartilage beginning to break down. Genetic factors undoubtedly play a role as well, but researchers know that extra weight seems to make the deterioration much worse even if it did not cause the break down in the first place.
It is known that a general population of patients will complain of knee pain approximately 12% of the time, but the figure increases to 60% in the heaviest group of patients.
Being heavy puts an extra burden on the knee joint. Additional pounds accelerate the usual wear and tear on the knee joint, grinding away more of the cartilage than would be expected.
Some speculate there may be something about fat cells that leads more directly to joint damage. Fat cells might manufacture a substance that injures the joint. This has not been proven as yet.
People gain weight as they get older and eventually the extra load causes joint pain. People start to avoid activities that cause the pain and they gain more weight. The joint then gets worse. Every year the person does less and less.
Joints require physical activity to keep the muscles surrounding them strong and when people are sedentary those muscles weaken and the joints take even more pounding which leads to more damage.
Joint failure occurs when the cartilage keeping the bones apart has completely worn away.
Studies have been done with groups of patients supervising their weight loss and exercise program. Patients who have lost as little as 10 to 15 pounds had a 40% decrease in reports of knee pain, which in many cases makes this equivalent to the relief offered by medication.
This reduction in knee joint pain allows patients to perform daily activities more comfortably such as walking and stair climbing.