The Benefits of Losing Weight Before Knee Replacement

People who are overweight and preparing for knee replacement surgery are often told to lose excess weight. Why? Losing weight helps ensure the post-surgical recovery process goes smoothly.

See How to Prepare for Total Knee Replacement

In fact, research suggests people may not have to lose all—or even most—of their excess weight to reap benefits.

Losing weight before knee replacement surgery may improve recovery, and create healthy habits to help avoid weight gain after surgery. Read: Undergoing Total Knee Replacement for Knee Arthritis

A study published in the Journal of Bone and Joint Surgery1 looked at 203 people undergoing knee replacement who had a BMI of 40 or more. (A person who is 5’9” and weighs 271 lb has a BMI of 40, for example.) Within the study group, 29 people (14%) lost 20 lb or more before surgery. Researchers compared those 29 people to the other people in the study, who lost 5 to 10 lb or did not lose weight at all.

See How Effective is Weight Loss for Treating Knee Arthritis Pain?


Losing weight may help knee replacement patients go home sooner

The researchers found that people who were morbidly obese and lost at least 20 lb were more likely to:

  • Have shorter hospital stays
  • Be discharged to their homes, rather than to rehabilitation facilities

Why are these differences important?

Recovering at home is usually better

Knee replacement patients are typically kept in the hospital for about a day, giving anesthesia time to wear off and patients a chance to practice walking on their new knee (with a walker or other assistive device). In general, surgeons recommend that patients do the rest of their recovery at home.

At home, patients are more likely to:

  • Avoid post-surgical infection and readmission to the hospital
  • Get better sleep
  • Eat foods they like

Together, these factors can lead to a more comfortable, safe, and satisfying recovery. In addition, a shorter hospital stay and/or less time in a rehabilitation facility will result in lower medical bills.


Significant weight loss, not perfection

What’s notable about this study is that the patients who lost weight were still considered morbidly obese. They did not have to reach what might be considered a “healthy” weight to reap benefits.

In other words, when it comes to losing weight prior to knee replacement surgery, people don’t have to strive for perfection. Smaller goals may be less intimidating, more achievable, and still have benefits.

Learn more:

Why Losing Weight Is the Best Treatment for Knee Arthritis

Choosing a Surgeon for Total Knee Replacement


  • 1.Keeney BJ, Austin DC, Jevsevar DS. Preoperative Weight Loss for Morbidly Obese Patients Undergoing Total Knee Arthroplasty. The Journal of Bone and Joint Surgery. 2019 Aug 21; 101 (16): 1440. DOI 10.2106/JBJS.18.01136