How difficult is it to lose weight before knee replacement? Is it necessary?

Only 20% of patients who are told to lose weight to have the knee replacement actually lose the weight.

Researchers at the University of Vermont, Indiana University School of Medicine, University of Virginia, and NYU Langone Health wrote in The Journal of Arthroplasty (1) about the difficulties obese individuals have in losing weight to get a knee replacement and for many patients, is it worth making them wait for a joint replacement until they lose weight? Especially when such a small percentage of patients actually do.

“Many believe that patients with body mass index (BMI) more than 40 (considered morbidly obese) have complications rates that may outweigh the benefits of surgery and should consider delaying it. However, the current literature on obesity and outcomes following total joint replacement is observational, very heterogeneous, and full of confounding variables.” What does this mean? No one is sure how extensive complication rates actually are in morbidly obese people getting a joint replacement.

To address this uncertainty, the researchers of this study suggest that maybe doctors should shift away from body mass index (BMI) as the sole measure for suggesting delay and weight loss before surgery. The researchers suggest considering 5 to 10% preoperative weight loss as perhaps a better guide for obese patients to prepare for knee replacement. They write:

“Body mass index (BMI) cutoffs to total joint replacements may also restrict access to care to our most vulnerable, marginalized populations. Moreover, only roughly 20% of patients instructed to lose weight for surgery are successful and the practice of demanding mandatory weight loss needs to be reconsidered until convincing evidence exists that supports risk reduction as a result of preoperative weight loss. Obese patients can benefit greatly from this life-changing procedure.”

Many patients undergoing knee replacement surgery are overweight or obese. The problem with enablers.

An April 2019 study from the Feinberg School of Medicine, Northwestern University published in the Journal of Clinical Nursing (2) noted that many people getting knee replacement are obese and it is difficult for these people to lose weight afterward.

  • “Many patients undergoing knee replacement surgery are overweight or obese. While obesity treatment guidelines encourage diet and activity modifications, gaps exist in understanding social and environmental (factors) determinants of these behaviors for knee replacement patients. Identifying these determinants is critical for treatment, as they are likely amplified due to patients’ mobility limitations, the nature of surgery, and reliance on others during recovery.”

Here were the problems identified:

The problem with enablers:

  • The people who continued with weight issues following knee replacement, despite the reliance on others to help them and their own mobility issues, still had availability of unhealthy food choices. (This could be a problem for enablers).
  • Positive results were achieved with weight loss when there was an availability of healthy food, keeping unhealthy options “out of sight,” and social support.
  • Weather was the primary activity barrier, while facilitators included access to physical activity opportunities and social support.

The hard truth: Some will lose weight because they want to, and some will not because they do not want to. Deniers and enablers.

Here is a research paper that will probably state the obvious, especially if you are the adult child of a parent who has bad knees and a big belly or the spouse of one.

This comes from August 2020 and was published in the journal BioMed Central Musculoskeletal Disorders (3). Here are the learning points:

  • Knee osteoarthritis affects mostly older adults and its primary risk factor is obesity.
  • This study looked to understand weight-control strategies, facilitators, and barriers toward weight control in older adults with knee osteoarthritis who preferred not to undergo physician-recommended total knee replacement.

In other words, we have older people with knee osteoarthritis who have been recommended for a knee replacement. They chose not to get a knee replacement. Yet weight is a concern. What are these people thinking? That is what the researchers wanted to know.

  • The study starts with 118 patients
  • Only 1 in 4 patients, 25.4% had body weight in the normal range.
  • More than half 55.9% reported having controlled their weight.
    • Controlling weight means that they were engaged in a program to obviously, control their weight. Their most common weight-control strategies were:
      • Diet
      • Diet and exercise together
    • Their weight control program did well when the patient was motivated to have good health, wanted to improve walking or movement, perceived that they had gained weight, wanted to look good, and advice from healthcare providers.
  • The people who had difficulties with weight control:
    • Denied that they even had a weight problem
    • They liked to eat or had difficulty on low-calorie diets
    • They did not like to be hungry.

Let’s understand this is a group of people who decided against knee replacement. About 80% or 4 out of 5 were going to try to delay or avoid the need for knee replacement by maintaining good weight and losing weight. About 1 in 5 are not only denying the knee replacement, they are denying the problem.

This last group, the deniers, are not the people we hear from. We hear from their adult children, their spouses, and sometimes even their adult grandchildren because not only is grandpa and grandma obese, but mom and dad are too and no one is doing anything about it.

  • Patients who undergo total knee replacement do not lose weight one year after surgery.

It is better to lose weight before total knee replacement?

Research: overweight patients are at a more than 40% greater risk and obese patients are at more than a 100% increased risk of knee replacement surgery compared to patients with normal weight

Doctors at Oxford University published in the journal Arthritis and Rheumatology (4) found that overweight patients are at more than 40% greater risk and obese patients are at more than a  100% increased risk of knee replacement surgery compared to patients with normal weight. Weight reduction strategies could potentially reduce the need for knee replacement surgery by 31% among patients with knee osteoarthritis.

The vicious cycle: I can’t lose weight because I am not mobile. I am not mobile because of my knee pain. I can’t lose weight

In our more than 30 years of experience helping people with knee pain, we have seen many patients who were overweight and considered obese. If you are reading this article, you know that there is “no magic pill,” there is “no magic formula,” to help you overcome the challenges of weight loss and knee pain. The most simple advice is that a person who desires to lose weight must burn more calories than they take in. This of course is easier said than done and the rationale behind some of the studies that we mentioned above in the tools and team required to help someone make it “easier done than said.”

We do present a lot of information on this website that may help provide an understanding of how one may lose weight with knee pain:

The evidence that cholesterol medication is sending you to knee replacement

Here is the snippet of this article: A patient comes in on a recommendation from a friend. “I am here because I have very bad knee pain . . . here is my story: I went to the doctor for my check-up. My blood work revealed slightly elevated cholesterol and I was advised that I need to take and was given prescriptions for medications that would lower my cholesterol. As a side note, I told my doctor that I did have some knee pain from a new exercise program. I said with confidence that hopefully, I can control my cholesterol with this new exercise program. My doctor said, “go easy on my knee.”

Soon after taking these new cholesterol medications, I felt a sharp pain in my knee. I wasn’t doing anything but walking to my car in the parking lot. My wife drove us home and she got me to the chair and we elevated my leg and got plenty of ice on it.

When your knee pain is coming from your unmanaged or uncontrolled Type 2 diabetes

In this article, we explore the challenges people with unmanaged or uncontrolled type 2 diabetes face with knee pain. If you are someone suffering from type 2 diabetes and knee pain, one challenge you may be facing is a diminished ability to heal your damaged knee. This non-healing will eventually lead to irreversible knee degenerative disease and the eventual recommendation of a knee replacement. Knee replacement complications in Type 2 diabetes are of course another great concern.

What is the best diet for my knee pain?

When people come into our clinic with significant knee pain, they will often ask our clinicians about what type of diet they should be on. Proper weight and proper diet are of course very important elements in healing. But how much can diet realistically do for your knee pain?

The right food stimulates healing, the wrong food can cause inflammatory reactions and make your knees feel worse. A realistic expectation one may have with food choice change is that you will probably look a little better, feel a little better, have a little more energy, and your knees may hurt less. To what degree depends on how aggressive you are with a change of diet and healing.

For more information on the different types of injections for knee pain. Please see our article: What are the different types of knee injections for bone on bone knees

If this article has helped you understand the problems of obesity and joint pain and you would like to explore Prolotherapy as a possible remedy for your joint pain, ask for help and information from our specialists

Research citations:

1 Blankstein M, Browne JA, Sonn KA, Ashkenazi I, Schwarzkopf R. Go Big or Go Home: Obesity and Total Joint Arthroplasty. The Journal of Arthroplasty. 2023 Oct 1;38(10):1928-37. [Google Scholar]
2 Hoffman SA, Ledford G, Cameron KA, Phillips SM, Pellegrini CA. A qualitative exploration of social and environmental factors affecting diet and activity in knee replacement patients. Journal of clinical nursing. 2019 Apr;28(7-8):1156-63. [Google Scholar]
3 Yeh WL, Tsai YF, Hsu KY, Chen DW, Wang JS, Chen CY. Weight control in older adults with knee osteoarthritis: a qualitative study. BMC musculoskeletal disorders. 2020 Dec;21(1):1-8. [Google Scholar]
4 Leyland KM, Judge A, Javaid MK, Diez-Perez A, Carr A, Cooper C, Arden NK, Prieto-Alhambra D. Obesity and the Relative Risk of Knee Replacement Surgery in Patients With Knee Osteoarthritis: A Prospective Cohort Study. Arthritis Rheumatol. 2016 Apr;68(4):817-25. [Google Scholar]

Get Help Now!

You deserve the best possible results from your treatment. Let’s make this happen! Talk to our team about your case to find out if you are a good candidate.