One orthopedic surgeon says there isn't a definitive weight limit for surgery, but “some surgeons do have their own personal cutoffs.”
Phyllis Warr, 60, needed knee surgery. Now retired, Warr was an English teacher at a Chicago-area high school, in an ancient building with three flights of stairs. With arthritic joint damage, she could hardly move about the school. “I had no cartilage in my left knee at all,” she says, “so it was bone on bone, rubbing every time I walked.”
She was heavy and had been since childhood. For years, she tried to find a surgeon willing to do a . “I had been told to have bariatric surgery and lose weight, and ‘Come back afterwards and we’ll do the surgery,” she says. But Warr didn’t want . She'd heard enough about possible side effects and wasn't interested.
Knees Paying the Price
It’s an orthopedics Catch-22: Obesity puts excess pressure on weight-bearing joints, so heavier people are more likely to need joint replacement. But obese patients face more risk from the surgery, and they get less improvement.
Demand is rising, though – especially for total knee replacement. Last June, a study found that among overweight patients, growth in the “has far outpaced” that of total hip replacements, although the reason isn’t certain, says study author Dr. Peter Derman, an orthopedic surgery resident at the in New York City.
Studies show obese patients who undergo total knee replacement have than normal-weight patients, and risk goes up with body mass index. That’s why heavier patients are often advised to lose weight before the operation.
There isn’t a hard-and-fast weight cutoff for surgery, Derman says, although “some surgeons do have their own personal cutoffs.” The goal is to encourage patients to lose weight to improve their health and obtain better surgical results.
Whether patients tend to lose weight after surgery – because they can now exercise without pain – is unclear. Follow-up studies are conflicting. Some find patients stay at the same weight, while other research suggests some patients lose weight, and others may actually gain.
Willing to Operate
In 2010, “on a whim,” Warr says, she checked out the orthopedic surgery department website at Rush University Medical Center in Chicago. She emailed a specialist there, detailing her health history, previous therapies like knee injections and her weight. An appointment was made. “I went in and I was ready for a fight – I mean, dukes up,” she says. Instead, team members looked at her old X-rays, took new images and said both knees were bad. And, they told her, “We can do this.”
Taken by surprise, Warr says she challenged the surgeon: “So I don’t have to argue with you?” No, she was told, they routinely performed the procedure on much larger patients. Nor were her diabetes or asthma barriers to surgery – they could be managed.
Still Heavy – Still Need Surgery
“Our population is getting heavier, and their knees are definitely paying the price,” says Dr. James Ryan, an orthopedic surgeon at in Corvallis, Oregon. With surgery, obesity “certainly doesn’t improve their chances of a successful outcome,” he says. “Whether or not it has a detrimental outcome is arguable.”
What is known, Ryan says, is that patients with BMIs in the 40-to-50 range do have an increased rate of infections and wound-healing problems, along with complications from obesity-related conditions such as high blood pressure, sleep apnea and diabetes. All of which, he says, can make recovery “more challenging.”
Durability is another concern. “Obviously, if you are placing more pressure across the prosthesis, the wear rate may be accelerated and the overall longevity of the implant may be compromised,” he says.
Ryan, who spends a lot of time talking to potential surgical patients about the importance of , emphasizes that multiple factors contribute to obesity. Dietitians and exercise programs can help, he notes, but it's also a matter of psychological issues, like depression, that can fuel overeating. And motivation plays a role. Some patients may undergo weight-loss surgery before knee replacement; others may do so afterwards – but some people simply don't want it. With heavier people, he says, the decision for knee replacement "really comes down to a very personal discussion with each patient, allowing them to recognize the chances they are taking if they elect to move forward with surgery, versus the potential gains they would have thereafter."
After surgery, he says, studies of obese patients show “functionally, they tend not to do as well as those who are of lower weight.” Still, he adds, larger patients report having much less pain, better function and ability to live more comfortably – and are just as satisfied.
Smooth Recovery
Warr’s left knee replacement went well – no complications, no infections and no problems with the incision healing.
Before surgery, she had already checked out a nearby rehabilitation facility, where the director assured her they would arrange for proper-size medical equipment. She had physical therapy on the premises twice a day and says the nursing staff was “wonderful." Once home, she through an outpatient physical therapy facility, where she could use the stationary bike and weight equipment.
In 2014, Warr returned to the same surgeon for a right knee replacement. She had a some trouble with pain management the second go-round. Now, however, she can walk three or four blocks and climb stairs (slowly) with no pain in her knees, although back issues make it difficult for her to stand in one place.