BMI and Knee Injuries: Being Overweight Can Cause Knee Injuries

July 11, 2006 12:04 PM

By Jim Brown, Ph.D., Executive Editor, Sports Performance Journal, Author, Tennis: Steps to Success

Overweight people in general and tennis players specifically are much more likely to suffer meniscus cartilage tears in their knee joints, according to a study conducted at the University of Utah School of Medicine and published in the May 2005 issue of the American Journal of Preventive Medicine.
The meniscus is a wedge-like cushioning structure in the knee (as well as in the shoulder and the jaw) that bears much of the load during standing, walking, and other daily and recreational activities. Meniscus tears are common knee injuries and until now, there has been limited research on any variables associated with the injury, much less risk factors. The new study is believed to be the first major research effort of its kind to examine one of those contributing factors.

A four-person research team determined overweight and obese categories using the Body Mass Index (BMI), a measure of body fat based on height and weight. Government guidelines define a healthy weight as one with a BMI of 24 or less. People with a BMI greater than 25 are considered overweight, and those at 30 or higher are classified as obese. The team collected data from procedures conducted during the five-year period among more than 500 older men and women. The patients had undergone operations at two hospitals in Salt Lake City and Provo, Utah. Then the findings were compared to a control group of more than 9,000 patients and adjustments were made for age and gender.

The investigators found that, among the subjects in the experimental group, men with a BMI of 27.5 and higher and women with a BMI above 25 were three times more likely to tear the meniscus. Men whose Body Mass Index exceeded 40 had a 15 times higher rate of the injury, while the rate in women in the 40 and over category was 25 times greater than those in the control group.

The medical and financial implications of the findings are staggering. Fifty-seven percent of adults in the United States are classified as either overweight or obese, according to Kurt T. Hegmann, M.D., M.P.H., who led the study and is director of the University’s Rocky Mountain Center for Occupational and Environmental Health. Dr. Hegmann estimates that the extra weight carried by Americans — at an average cost of $3,000 per operation — accounts for up to 450,000 of the 850,000 operations for meniscus repairs annually. “There is a potential savings of $1.3 billion in the costs associated with meniscus tears and overweight and obese people,” he says.

Solution Easier to Define Than to Execute
The solution to the problem is easy to propose, but difficult to achieve. Conclude the researchers, “A population-based weight management program could decrease future burden on orthopaedic and medical care systems due to meniscus surgeries and treatment of other obesity-related conditions.”

© 2006 HMS Publishing, Inc.
Jim Brown will be contributing new content to this site on a monthly basis. If you have a question for Dr. Brown please feel free to email him at