Weight loss takes a load off of knee deterioration


Anyone suffering from osteoarthritis of the knee knows all too well the disabling and limiting mobility of this condition causing pain and stiffness.  Now a new study is showing that losing weight can slow the development of osteoarthritis of the knee by reducing the degeneration of knee cartilage.

Osteoarthritis is the most common form of degenerative joint disease worldwide and is a leading cause of disability in people over the age of 50.  It is considered a wear-and-tear form of joint disease that tends to affect the load-bearing joints, especially the hips and knees, crucial for movement.  It occurs when the cartilage cushioning the joints thins and wears away causing the bones to rub together.  Symptoms of the condition often begin with joint stiffness and discomfort but without treatment, the tissue surrounding the joint can become increasingly inflamed, and can eventually lose some or almost all range of motion.

A major risk factor for osteoarthritis is being overweight to obese.  Carrying excess weight can put extra pressure on the joints and cartilage leading to wear-and-tear.  Because of carrying additional weight, it can be common for overweight to obese individuals to alter their gait which can affect the knee joint. It has also been noted that people with higher levels of body fat can have higher levels of proteins in the blood triggering joint inflammation which can lead to osteoarthritis. 

For this study, data was collected on 640 obese and overweight people who had mild osteoarthritis or were at risk of it as determined by MRI scans.  The average age of the participants was 69 and each one were part of the Osteoarthritis Initiative, a nationwide U.S. study on the prevention and treatment of knee arthritis.  Participants were divided into three groups: those who lost more than 10 percent of their body weight, those who lost 5 to 10 percent of their body weight, and those who weight remained stable. 

Researchers in the study also looked at the degeneration of all knee joint structures, including the menisci, articular cartilage, and bone marrow.  Meniscus is a piece of cartilage found where two bones meet with the menisci protecting and cushioning the joint surface and bone ends.  Articular cartilage is the smooth, connective tissue covering the ends of bones where they come together to form joints.  When cartilage is healthy, it makes it easier to move allowing the bones to glide over each other with very little friction. 

The study spanned over 48 months during which the researchers monitored changes in each participants’ weight and changes in knee degeneration.  The conclusion from the results was that compared with the control group, participants who had lost at least 5 percent of their body weight had slower knee cartilage degeneration.  Participants who lost more than 10 percent of their body weight had an even greater reduction of degeneration within the knee.  In addition, the menisci degenerated much slower in overweight and obese individuals who lost more than 5 percent body weight with the effects being the strongest in those with substantial weight loss. 

The researchers believe that the results from the study help demonstrate that weight loss may lower the risk of osteoarthritis among people who are overweight to obese by slowing down the progression of degeneration.  Both the articular cartilage and menisci showed a much slower rate of deterioration among the individuals who had lost at least 5 percent body weight. 

It has been pointed out however, that even people who are thin can experience osteoarthritis of the knee.  Even though this study shows a correlation between losing excess weight and slowing down of osteoarthritis of the knee, it does not prove causation.

But what the study does provide is information on the importance of developing individualized treatment and therapy strategies and how lifestyle interventions such as weight loss appears to help slow down or maybe prevent knee joint degeneration.