Not All Obese Patients Need To Lose Weight Before Total Joint Replacement

Increased weight gain leading to obesity and the inability to move or involve in physical activity is widely prevalent in older adults. It adds on to their risk of weak bones and the chances for fracture and the treatments thereof.

Weight loss is a main criteria in the treatment of arthritis. But a new study finds that obese patients who underwent knee or hip replacement surgery reported virtually the same pain relief and improved function as normal-weight joint replacement patients six months after surgery.

‘Obesity is associated with a greater risk of hip and knee replacement surgeries but, obesity itself should not be a deterrent to undergoing total joint replacement to relieve symptoms.’

"Our data shows it's not necessary to ask patients to lose weight prior to surgery," said Wenjun Li, PhD, associate professor of medicine and lead author on the study. "It's challenging for a patient who is severely overweight and suffering in pain to exercise--often they just can't do it.

The aim of the study, published in the Journal of Bone and Joint Surgery, was to evaluate the extent of pain relief and functional improvement in total joint replacement patients with various levels of obesity.

The researchers concluded that while obesity is associated with a greater risk of early complications, obesity in itself should not be a deterrent to undergoing total joint replacement to relieve symptoms.

Prior research has documented that obesity is associated with a small, but increased likelihood of infection after total knee replacement, which may discourage obese patients from having surgery.

"However, in this paper we report that obese patients have comparable pain relief and functional outcomes after surgery," said Patricia Franklin, MD, MBA, MPH, professor of orthopedics & physical rehabilitation. "Patients should know that these benefits may outweigh risks."

Preoperative and 6-month postoperative data on function, joint pain and body mass index (BMI) from a national sample of 2,040 patients who had undergone total hip replacement and 2,964 who had undergone total knee replacement from May 2011 to March 2013 was collected.

Preoperative and postoperative function and pain were evaluated according to BMI status, defined as under or of normal weight, overweight, obese, severely obese, or morbidly obese. A greater obesity level was associated with worse pain at baseline but greater postoperative pain relief, with average postoperative pain scores at six months similar across the BMI levels.

"This surprised us a little bit. Past analysis showed that obesity is associated with outcomes to some degree, but here we see the magnitude is so small it won't make much difference, and severely obese patients can benefit a lot from the surgery," said Dr. Li.

Patients who can lose weight should, but many people can't, or it will take a long time during which their joints will worsen. If they can get the surgery earlier, once function is restored they can better address obesity.

"Losing weight by making appropriate dietary changes and increasing the calories burned each day through water exercise programs and other aerobic, non-weight bearing activities is always appropriate to decrease the risk of complications for overweight patients," said FORCE-TJR co-investigator Dr. Ayers.

"This manuscript adds to our collective knowledge regarding the risk benefit ratio of total joint replacement surgery in obese patients. The debate will continue in the morbidly obese patients with BMI over 40, and the super obese with a BMI over 50, regarding what steps can and should be taken to lower the risks before these elective surgical procedures."

Source: Eurekalert