Researchers find weight loss not necessary for joint surgery

WORCESTER, Mass. (AP) For Blake Kadra, arthritis had caused him to stop playing sports, rendered walking and yard work painful, and made him a candidate for total knee replacement surgery.

But before the surgery, doctors recommended Mr. Kadra lose 20 pounds to see if it would alleviate the pain.

“It’s hard to do when you can’t move,” Mr. Kadra, 60, said of losing weight.

It’s a dilemma shared by many candidates for hip and knee replacements. Doctors recommend losing extra weight prior to surgery to decrease risks from infection and to see if it will ease pain. But weight loss is difficult when exercising hurts.

But if you think you must lose those extra pounds before a knee or hip replacement, think again, as researchers with UMass Medical School found long-term relief from joint replacement surgery was almost the same in obese and non-obese patients.

“The conventional wisdom is that the lower your body weight, the lower your body mass index, the better you will do in joint replacements, and there has been an increasing push to say that if you are obese you should not have joint replacement – either knee or hip replacement,” Dr. David C. Ayers, chairman of orthopedics and chairman and professor of orthopedics and physical rehabilitation at UMass Medical School, said Thursday.

Dr. Ayers is the co-author of a study reporting the findings published last month in the Journal of Bone and Joint Surgery.

“What this study shows is that people who are overweight and are obese get the same type of pain relief and improved function that non-obese patients do,” he said.

Approximately 7 million Americans were living with a hip or a knee replacement as of 2010, and approximately 1 million joint replacement surgeries are done each year, according to the Mayo Clinic.

The surgeries are becoming more common and the patients getting younger. In fact, hip and knee replacements combined now represent the highest volume surgery in the United States, according to Dr. Patricia Franklin, professor of orthopedics and physical rehabilitation at UMass Medical School and a co-author of the study.

But prior research has documented that obesity is associated with an increased likelihood of infection following joint replacement surgery. And most total joint replacement surgical patients are obese, Dr. Franklin said.

Weight loss through diet and exercise is thus regularly prescribed for the overweight in advance of total joint replacement surgery.

But while surgeons and patients have been well aware of the risks of joint replacement surgery for the obese, Dr. Franklin said there was “a gap in the literature” of the potential benefits of the surgery for those who are overweight.

So, researchers at UMass Medical School collected data on preoperative and six-month postoperative function, joint pain, and body mass index from a national sample of 2,040 people who had total hip replacement and 2,964 people who had undergone total knee replacement between May 2011 and March 2013. Preoperative and postoperative function and pain were evaluated according to body mass index status – defined as under or of normal weight, overweight, obese, severely obese, or morbidly obese.

Patients across BMI levels 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.

“Total knee and hip replacement can be fairly uniformly successful in improving quality of life,” Dr. Franklin said. “That does not diminish the need to minimize risks … but it’s affirming to be able to communicate that patients across body mass index status are reporting significant quality of life gains.”

Dr. Franklin said that to minimize risk of infection, doctors will continue to recommend weight loss for overweight and obese patients in anticipation of total joint replacement surgery. But she said the study should help patients and their doctors make a more informed decision about whether, and when, to undergo total joint replacement.

“I think patients are finding the information useful because they have a full picture of the benefits and risks,” Dr. Franklin said. “There’s two goals – one is minimize my risk and one is to maximize my benefits – and now we have the data to counsel you on both.”

As for Mr. Kadra, he has had both of his hips replaced since 2012 and is currently recovering from the knee replacement.

“I would stress that anybody try to lose weight before the surgeries,” Mr. Kadra said. “However, I’m still successful with my surgeries anyway, in spite of my weight.”

The 5-foot, 11-inch Hopkinton resident is still working on losing another 20 to 30 pounds to get back to a more manageable 225 pounds, but he is confident that will come.

“I can do it now,” Mr. Kadra said. “I’m not hurting.”