“Come back when you’ve lost 40 pounds.” That’s something obese patients have heard often when being evaluated for a hip or knee replacement for severe arthritis. And sometimes the recommendation is to lose even more — 50, 75, or even 100 pounds… as if that’s an easy or realistic prospect.
As you might expect, patients hearing this often feel disappointed and disheartened. After all, most have already tried hard to lose weight with limited success. Their arthritis pain impairs their ability to exercise, and decreasing activity has contributed to their weight gain. So being told to lose significant weight before they can be considered for joint surgery sounds a lot like being told it’s just not going to happen.
Why should obesity preclude joint surgery?
While the surgeon’s recommendations may be disappointing, the rationale seems sound: people carrying a lot of excess weight have long been considered at higher risk for complications, and less likely to experience the profound pain relief expected from this major operation. Indeed, several studies describe higher rates of infections and dislocations and lower rates of good results after hip or knee replacement among the obese, especially the severely obese.
Importantly, many of these studies are more than a decade old, and newer studies are beginning to paint a different picture. A recent study on the risks and benefits of joint replacement among the obese sheds new — and positive — light on an issue that affects many thousands of people.
Research suggests that being obese should not preclude joint replacement
Researchers analyzed the results of more than 5,000 people having hip or knee replacement surgery, comparing pain and function before and six months after surgery. Here’s what they found:
- Those who were the most obese (about 25% of those in the study) had more pain and poorer function prior to surgery than those who were leaner.
- The amount of functional gain in obese individuals six months after joint replacement was significant, and similar to that experienced by those who were not obese.
- Pain relief was greater among the most obese than other weight groups. After surgery, pain levels were similar in all weight groups.
The authors conclude that “obesity in itself should not be a deterrent to undergoing total joint replacement to relieve symptoms.” However, the potential for more complications must be considered as well, something this study did not formally examine.
A 2021 analysis looked at people with extreme obesity (BMI of 40 or higher), cardiovascular disease, and type 2 diabetes. The researchers found knee replacement surgery still offers a good balance of costs and benefits.
Given high rates of obesity and arthritis in this country, the results of these studies will likely apply to many people. And they suggest that surgeons should change expectations about what surgery can offer people with obesity and severe arthritis.
The bottom line
While avoiding obesity in the first place is still preferable, there is increasing evidence that the benefits of joint replacement surgery are not limited to those who are lean. If this new research is confirmed by others, we may see fewer obese people turned down for joint replacement surgery in the future.
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