Running, jumping, bending and even the simple task of walking are all actions that require the use of your knees. These essential hinge joints are a combination of bones, muscles, ligaments and tendons working together to provide large range of movement.
It's safe to say that knees are one of the most important body parts required for active living and should not be taken for granted.
In recent years, however, people's delicate knees have undergone more replacement surgeries than ever before with numbers more than tripling between 1993 and 2009. A recent study published in the June 2014 Journal of Bone and Joint Surgery(JBJS) has linked this spike to the increasing number of overweight or obese individuals in the U.S.
Before concluding their results, researchers reviewed at least 10 years of national data to rule out other possible factors. Data included the number of knee replacements, length of hospital stay, in-hospital mortality and orthopedic workforce trends.
"We found that this differential growth rate in total knee replacement procedures could not be attributed to changes in physician or hospital payments, length of hospital stays, in-hospital death rates, or surgical work force characteristics," said lead study author Peter B. Derman, in a statement.
Further research revealed that the increase in volume of overweight individuals (those having a Body Mass Index greater than 25), accounted for 95 percent of the increased demand for knee replacements.
The study also highlighted that younger patients are especially being affected by this relationship as those ageing from 18 to 64 are experiencing a faster climb in overweight conditions compared to those ages 65 and older. As a result, the number of younger patients undergoing knee replacements rose 56 percent between 1993 and 2009.
"We already know the more stress a bone's joint experiences, the shorter its lifespan as it wears down," says Dr. Paul DeHaan, an orthopedic surgeon on staff at Advocate Good Shepherd Hospital in Barrington, Ill. "This study emphasizes how easily extra pounds can exhaust a knee joint to the point of surgical replacement. In fact, every pound in excess of your normal weight adds about three additional pounds of pressure on your knee each time you take a step."
"As obesity rates continue to rise, we can expect the demand for knee replacement surgery to increase as well," Dr. DeHaan adds. "To prevent this problem, people need to not only stay at healthy weights, but should also try to regularly stretch, strengthen leg muscles and wear proper shoes."