Obesity takes heavy toll on knee arthritis

New studies will help patients better understand the role that obesity plays in knee arthritis and recovery from knee surgery

More than 14 million visits were made to physicians' offices in 2008 by patients with knee problems. Five new studies presented at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) look at the effect that obesity has on knee arthritis and a patient's ability to recover from knee surgery.

Does Obesity Cause Irreparable Damage To Knees Despite Weight Loss? (Embargo: February 15)

One new study found that while weight loss via bariatric surgery may improve knee pain in obese patients with knee osteoarthritis, there may be permanent damage to the knee from being morbidly obese.

The investigation included 10 morbidly obese patients with knee osteoarthritis who were evaluated before and after bariatric surgery. Patients lost an average of 51 pounds in one year. One year after surgery, knee pain and function improved significantly.

"For a long time people felt there was nothing they could do to mitigate the debilitating effects of knee arthritis, but now we know that surgically-assisted weight loss is a way that folks can help themselves," says Michael S. Sridhar, MD, co-investigator and resident at Emory University. "However, there is probably some element of irreparable damage from being morbidly obese that may constrain the improvement in knee pain despite significant weight loss. Looking at the actual joint surfaces with advanced imaging to assess damage is the exciting next step in studying the evolution of knee arthritis in the obese population."

Are 'Super-Obese' Patients At Greater Risk For Post-Surgery Complications? (Embargo: February 15)

Also, two new studies released today examine whether obesity contributes to greater complications after hip and knee replacement surgery. The first study considers patients in the "super obese" category who have a body mass index (BMI) greater than 45. Few studies have examined whether complication rates for total joint replacement (TJR) patients may increase for "super-obese" patients.

This study compared the outcomes after TJR in 137 "super-obese" patients versus 63 non-obese patients.

Ran Schwarzkopf, MD, co-investigator and chief resident, New York University Hospital for Joint Diseases, and his research team found that the number of overall complications were significantly higher for the "super-obese" compared to non-obese. Among "super-obese" patients, each 5-unit increase in BMI over 45 was associated with a statistically significant increased risk of having in-hospital and post-operative outpatient complications or readmission. Also, days to discharge were found to increase by almost 14 percent for each 5-unit increase in BMI over 45.