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The Impact of Weight on Total Joint Replacement: Part 2- A Surgeon’s Perspective

By | Announcements, Bones of the Bay

By: Katheryne (Kat) Downes, Ph.D., MPH
Director of Health Research, Outcomes & Evaluation
Florida Orthopaedic Institute

NOTE: This post is not a substitute or replacement for professional medical advice. If you have any questions about your medical condition or treatment, please seek your doctor’s advice.

In Part 1 of this post, we talked about what BMI is, how it is interpreted, and the risks during and after surgery.

To dive into this topic a bit more, I met up with Dr. Michael Miranda, who is an Adult Reconstruction (a.k.a. joint replacement) surgeon with Florida Orthopaedic Institute, to talk about how he thinks about weight and joint replacement surgery.

KD: So, first, thank you for agreeing to do this. You are my first Bones of the Bay interview and, therefore, my guinea pig! Today, we are talking about the role that a patient’s weight and BMI play in deciding to do joint replacement surgery. Let us get started: How do you decide whether to operate on a patient when it comes to their weight in particular?

MM: Well, we have a loose cutoff of a BMI under 40. So, if it is under 40, for me, they are a candidate for surgery. If they are over 40, we counsel them on diet, weight loss, activity modification, etc., to try to get to the target BMI of 40. If they are well above that, what is called ‘extreme obesity’ (BMI 50+), we try to get them as close to 40 as possible. Not everyone is going to get all the way down, though. So, if a patient has a BMI of 50, I take the approach of trying to get them to lose 10% of their body weight and see that they are actively trying to get their weight down.

But there are going to be some people who have a BMI that’s just too high- 10% isn’t going to be enough- they are just too high risk for surgical complications. They aren’t going to be candidates for joint replacement surgery. That’s my general approach.

Now, to clarify: the cutoff of a BMI of 40 is for patients who only have a high BMI and don’t have other issues. If they have other risk factors, like uncontrolled diabetes, heart disease, uncontrolled high blood pressure, smoking, etc., we don’t have as much flexibility. We must be strict: patients with multiple conditions need to be under 40.

If they are a smoker and a BMI of 45, I’m not going to do it. If they are an uncontrolled diabetic with a BMI of 45, I’m not going to do it. That is too many things- too much risk for the patient – something is going to go wrong with their surgery or afterward.

A lot of what we talk about is based on science: hemoglobin A1c, BMI, smoking, etc., but it is also based on my experience with patients. Now, if a patient then quits smoking, gets their diabetes under control, and loses 10% of their body weight, but the BMI is still a little over 40, I think they should be rewarded for fixing some of their problems, and I am much more likely to consider surgery for that patient.

KD: So, I have spent a lot of time reading about the relationship between BMI and joint replacement surgery for the blog, but for our readers, I want you to talk to me as if I were a patient: What are the things you are worried about that could go wrong with surgery (or afterward) if my BMI was too high?

MM: The biggest thing that I talk about with patients is infection risk. Your risk goes up a lot with higher BMIs. If you get an infection in the joint that was replaced, you are typically in the hospital multiple times and have multiple surgeries. You have a higher risk of most complications- like blood clots- because you can’t move around much. You have to be on antibiotics for a long time. You can get continuous pain and poor motion in the joint because of scar tissue that develops. And you are out of work for a really long time. Sometimes, the infection is so bad that the implant must be removed entirely and replaced with a new one.

So, infection is the biggest issue because the risk is so high, and the morbidity is so horrible.

The second thing is the role of the patient’s weight on getting arthritis in the joint. The more you weigh, the more pressure you put on your joints, and the faster they wear out. If your weight is high and you have already worn out your natural joint, what do you think will happen to the artificial one that is made of metals and plastics? It will also wear out more quickly, and you will need another joint replacement.

The third would probably be for patients who are both obese and diabetic: We know that having a joint replacement surgery puts a lot of stress on the body. For patients with diabetes, it can send them into an uncontrolled state. Meaning, the patient will start having a hard time keeping their blood sugar and insulin levels normal, even with their regular medications. The combination of obesity and uncontrolled diabetes can then further increase the risk for infection after surgery.

Last, we know that sleep apnea is common for obese patients. Sleep apnea is a super high-risk factor for complications during the surgery: the patient can start having problems breathing during the operation.

KD: Alright, so that is for a patient with a BMI above 40. But, as we saw in the table, a BMI of 30 or higher is considered obese. So, if you have a patient who has a BMI less than 40 but is still above a healthy weight, do you still counsel them about healthy behavior changes?

MM: Yes. I’ll tell them that we will schedule your surgery in the next two months, and anything that you can do to improve your health during that time- losing weight, improving your nutrition, getting more exercise, things like that – will help you get through the surgery with less pain, recover more quickly, and get back to your life faster. I have that conversation with almost everyone, except maybe someone who is a runner or something like that. It is probably good advice no matter what your weight is. Anything that you can do to get yourself in better shape can make a difference: get into a pool, ride a bike, eat healthy, and drink more water. It’s going to make your recovery so much easier and faster.

KD: Yea- getting into a pool is a way to work out that takes a lot of the weight off your joints. Even doing laps by walking from one end of the pool to the other can be good exercise!

I really like what we have talked about so far. In Part 1 of this blog post, I have a lot of content around the science of weight and how it affects your health. But the goal for these types of interviews is to give you a chance to talk to patients about some important things that you just normally don’t have enough time for. A lot of the time, you only get about 5 minutes to talk to a patient at an appointment, and a lot of these things require a LOT more than 5 minutes!

MM: Yea, I’ll definitely refer my patients to this as a resource to read. We know that this is a really hard topic and that a lot of patients get very frustrated with trying to lose weight before a surgery- many give up. We don’t want that.

KD: This was something I was planning to bring up later, but you’ve brought it up now. I found this study (1) that was following patients who had a high BMI and needed joint replacement surgery. The results were depressing. For patients with a BMI of 50 or higher, after being told that they would need to lose weight to be eligible to have a joint replacement surgery, only 20% ended up having the surgery. So, I wanted to ask you: Why do you think this happens?

MM: Pain changes your life. When you are in a lot of pain, as is often the case for knee and hip replacement patients, you don’t want to get up and move around. You want your knee fixed and for the pain to stop. They aren’t thinking of the long-term effects on their health, just the joint that is hurting them. So, I think it’s “my knee hurts, I just want my knee fixed, and then I’ll do what I need to do to lose weight”.

Also, food is often comforting. So, if you are in a lot of pain or you’re in a bad mood, you want to go eat something that will make you feel better. A lot of us do that. I think I probably even do that sometimes. Pain makes you feel miserable.

It’s an awful cycle, and you keep going down this bad path. It snowballs.

KD: Yea, I think most of us were always told: If you want to lose weight, you have to exercise more. The great news is that we know now that that’s not actually true. Eating habits are the primary driver for your weight. This is not to say that exercise isn’t super important for your health- especially for your heart- but it’s not the main way to lose weight.

MM: YES! A huge part of weight loss. People really need help with their nutrition. They’ll say, “I don’t eat that much!” But what you are eating is really important. You may not be eating that much, but it could be the wrong things. I think this is a huge problem.

KD: Oh, yes. This is definitely an issue in the US, as well as in many other countries. The food that is easiest to get (fast food) is calorie-dense and nutrient-poor. Meaning, it is a lot of calories and does not give you any of the good things, like vitamins. If you’re eating a lot of that, it spells disaster. And healthy food is expensive and more difficult to get.

So, we talked about that you won’t operate if a patient has a BMI much above 40 or if they have other diseases in addition to the high BMI.

What do you specifically advise patients to do to lose weight?

MM: We talk to them about surgical and non-surgical options for weight loss. These are the two big avenues. You’re going to need to try non-surgical options first. What I’ve seen be most helpful for patients is a well-organized plan- something like Weight Watchers. You need help, routines, plans, and support. Those have been shown to be the most successful for weight loss.

We’ll refer patients to a couple of physicians that are local that we’ve had a lot of success with too. They typically do non-operative weight loss: either a diet plan or a plan plus medications.

KD: Are these bariatric surgeons? [bariatric surgeons specialize in weight-loss surgeries like gastric bypass]

MM: No, there is a family practice physician, Dr. Ling, out in Brandon. They do diet and medications. There’s also Dr. Garcia’s family’s company. They do non-operative weight loss too.

KD: They are going to start running a practice in our Telecom North Tampa main location!

MM: Dr. Garcia’s family’s company?

KD: Yes! Vivaliti. And they are going to be up on the second floor. They started seeing patients on April 29th!

MM: That’s great to know! I was just asking Lee [Lee Levanduski – FOI’s COO] about referrals to that group.

KD: Yes. I think everyone is excited to see how this could benefit our patients.
Ok, back to weight-loss recommendations. What else?

MM: Yes, surgical options. If they have a super high BMI and they tell me they’ve already tried diet changes, and they’ve thought about trying surgery, we’ll refer them to bariatric surgery for evaluation. We try hard to make sure we give our patients options and a path forward; that’s really important. You can’t just say, “your BMI is too high, you can’t have surgery, goodbye.” That’s not helping our patients. We try to include that as part of the training for our adult reconstruction fellows. This is something incredibly hard for patients. We want to help them navigate this journey to help them get healthier.

We aren’t saying you can’t have surgery. We are saying that, right now, you are too high of a risk for complications, and we need to get you to a lower risk category. We don’t want anything bad to happen to you. We need to get you tuned up for this. We want you to have a successful surgery, get better quickly, and be able to get you back to being active.

KD: I think that is a great way to think about it, and I wish more surgeons had your attitude.
Well, that is all the time we have today, and a special thanks again to Dr. Michael Miranda for being my first ‘guest’ on the blog. Hopefully, there are some patients out there that will find this blog and conversation interesting and informative.

To learn more about Dr. Miranda, you can visit his provider page.

If you would like to schedule a consultation, you can schedule an appointment online here or call us at 813-978-9797.

Subscribe to this Blog: Email us at and put “SUBSCRIBE” in the subject line.

Questions? Suggestions for a future topic? Please email us at

Reeves RA, Hefter GD, Pellegrini VD Jr, Drew JM, Barfield WR, Demos HA. The Fate of Morbidly Obese Patients With Joint Pain: A Retrospective Study of Patient Outcomes [published online ahead of print, 2021 Mar 2]. J Arthroplasty. 2021;S0883-5403(21)00229-1.

The Impact of Weight on Total Joint Replacement: Part 1- Understanding BMI and Obesity

By | Announcements, Bones of the Bay

By: Katheryne (Kat) Downes, Ph.D., MPH
Director of Health Research, Outcomes & Evaluation
Florida Orthopaedic Institute

NOTE: This post is not a substitute or replacement for professional medical advice. If you have any questions about your medical condition or treatment, please seek your doctor’s advice.

You might be reading this post because you (or a loved one) are thinking about having a joint replaced and wondering whether your current weight will be a problem.

Or maybe you were just told that you need to lose weight before you can get a joint replaced.

Whatever brought you here today- Welcome to FOI’s Bones of the Bay Blog! Here we discuss important medical topics in easy-to-understand language to help patients learn more about their health and healthcare.

Today’s post is all about the role of weight in deciding to have joint replacement surgery and the impact your weight can have on your recovery from surgery. In Part 1, we will talk about what numbers a doctor looks at to evaluate your possible risks, why those numbers are used, and why your weight matters more broadly. In Part 2, we sit down with Dr. Michael Miranda to talk about how he thinks about a patient’s weight when making decisions about whether to operate and his advice for patients who may be struggling with this issue.

So, let us start with the basics.

How does your doctor look at your weight?

When you see most doctors, they usually have you step on a scale to record your weight and ask you for (or measure) your height. They can calculate your Body Mass Index (or BMI, for short) with these two numbers. The BMI is used as a general health screening tool, the same way that taking your temperature and blood pressure are used to watch other parts of your health.

You can use this free calculator from the CDC website to determine your BMI right now.

Once your doctor has this number, they compare it to a chart like this to figure out what category your weight is in:

If you just found out that your BMI is above the “healthy” category- you are not alone:

The United States is in an ‘obesity epidemic’ because almost half of the country (42.4%) now has a BMI of 30+, and this number has been rising year after year. (1)

Where did BMI categories come from?

The categories are based on studies that looked at people with different BMIs and how often they were getting different diseases. We have learned that the risks start going up when you have a BMI that is 25 or higher. But the risks increase a lot when you have a BMI of 30 or higher, which is classified as “obesity.” (2-3)

According to the CDC (2-3), obesity increases the risk of Death, Gallbladder disease, Heart blockages, High blood pressure, Osteoarthritis, Stroke, High cholesterol, Sleep apnea, Body pain, Type 2 Diabetes, Some cancers, Chronic inflammation.

*Obesity has also been shown to increase the risk of severe illness with COVID-19 infection. (4)

The risks of all the above diseases tend to increase more as the BMI goes higher. So, risks are higher for BMIs in Class II vs. Class I and higher for Class III vs. Class II.

The fact that almost half of the country is now obese means that our health risks are generally going up as a nation. Not surprisingly, it also means that healthcare costs are going up.

What causes obesity?

You might be tempted to think that the answer is just: eating too much and exercising too little.

The truth is that it is a lot more complicated than that…

Yes, the number of calories you eat daily, minus the amount you burned off will generally determine whether you are losing or gaining weight (or holding steady). But what determines how many calories you eat and how much you burn off each day?

There are a few great resources for this (5-6), but here is a quick summary:

Environment & Behavior:
Do you have access to healthy food? Or do you live in a ‘food desert’, where healthy food is far away, and the nearest food is very bad for you? (junk food, candy, etc.).

Do you have a safe place nearby to walk/exercise?

Is your pantry or fridge stocked with mostly unhealthy options? (It’s harder to make healthy decisions if you are surrounded by junk food!)

Do you tend to go out to eat with friends and family often? If so, peer pressure (both obvious and not so obvious) can make you eat more food than if you were alone. (7)

Do you have a job that has you sitting for 8 hours a day at a desk? That is called a “sedentary” job, and it’s also not good for you! (8)

There is some early evidence that certain people do have genetics that make it easier for them to gain weight and harder to lose weight.

Other diseases and medications:
Certain diseases, like polycystic ovary syndrome (PCOS) and hypothyroidism (where your thyroid is under-performing), are associated with weight gain. Certain medications can also result in weight gain.

Stress & sleep:
Stress has both direct and indirect effects on our bodies. Being stressed for a long time (chronic stress) exposes us to certain hormones (like cortisol), which can harm us if we have high levels for too long. It can throw your body’s function out of whack: it can result in system-wide inflammation and pain. (9)

Indirectly, many people also tend to eat more and sleep less when they are stressed out. Not getting enough sleep can also throw our body “off” and lead to weight gain.

The mind-body connection:
There is also a complex mind-body connection around food, hunger, and feeling full (called “satiety,” pronounced “SAY-shuh-tee”). Some signals happen when we chew and when our stomach stretches from the food going into it. But there is a time delay- it’s not instant. We are supposed to have signals that bounce back to say: “We’re full – don’t eat any more.” For some people, this system doesn’t work correctly. Therefore, they can feel hungry when they aren’t, and might not feel full even though they are stuffed! (10-11)

Eating for comfort and for pleasure is also definitely a thing! (12)

Knowledge about nutrition and exercise:
Did your parents teach you what a healthy portion size is? Did they tell you how many glasses of water you should be drinking daily? Did they teach you about calorie density? Did they teach you how to read a nutritional label on food?

Mine didn’t. And I would guess that most of you didn’t get that information from your family either. And it wasn’t because they didn’t want us to know- it was because they also weren’t taught these healthy habits! Yet, it is incredibly important for being truly healthy.

Did you know that the average American portion served in a restaurant is generally 2-3x the size it used to be? (13) And it’s not just the amount of food that is piled on the plate- it is the size of the food itself. For example, 20 years ago, the average cheeseburger was 4.5oz… today, it is 8oz! This is why there has been a push toward showing calorie information on restaurant menus and making nutrition labels easier to read. (13)

I was personally horrified when I learned how many calories were in one of my favorite frozen dessert treats! The same thing happened with some of my favorite meals at certain restaurants. In some cases, it’s the entire days’ worth of calories (or sometimes 2-3x that amount!).

So, this is all to say that there are a lot of different reasons why so many of us are struggling with our weight, but there are definitely some great options out there to help you make the changes if you want to be healthier.

Okay, so now I know a lot more about why obesity happens and the health risks, but what does this have to do with joint replacement surgery?

In addition to increasing the risk of developing other diseases, obesity has also been shown to increase the risk of certain outcomes during and after surgery:

  • Increased use of pain medication after surgery. (14)
  • Having to stay overnight at the hospital when you were supposed to be discharged the same day. (15)
  • Longer surgery time. (16-17)
  • Surgical complications. (16)
  • Longer hospital length of stay (17-18)
  • Needing additional surgeries. (reoperation) (19)
  • Being re-admitted to the hospital due to a problem specifically with your joint replacement. (19)
  • Surgical site infection. (19)
  • Infection of the replaced joint. (called ‘periprosthetic infection’) (20)

In short, your doctor is worried about your weight because a too-high BMI can put you in danger during surgery and make your recovery more difficult.

In Part II of this post, I sat down with Dr. Michael Miranda to talk about how he thinks about weight and total joint surgery.

Click here to read our conversation.

Subscribe to this Blog: Email us at and put “SUBSCRIBE” in the subject line.

Questions? Suggestions for a future topic? Please email us at


  8. Stamatakis E, Gale J, Bauman A, Ekelund U, Hamer M, Ding D. Sitting Time, Physical Activity, and Risk of Mortality in Adults [published correction appears in J Am Coll Cardiol. 2019 Jun 4;73(21):2789]. J Am Coll Cardiol. 2019;73(16):2062-2072. doi:10.1016/j.jacc.2019.02.031
  9. Hannibal KE, Bishop MD. Chronic stress, cortisol dysfunction, and pain: a psychoneuroendocrine rationale for stress management in pain rehabilitation. Phys Ther. 2014;94(12):1816-1825. doi:10.2522/ptj.20130597&lt
  10. Miquel-Kergoat S, Azais-Braesco V, Burton-Freeman B, Hetherington MM. Effects of chewing on appetite, food intake and gut hormones: A systematic review and meta-analysis. Physiol Behav. 2015;151:88-96. doi:10.1016/j.physbeh.2015.07.017
  11. Murphy KG, Bloom SR. Gut hormones and the regulation of energy homeostasis. Nature. 2006;444(7121):854-859. doi:10.1038/nature05484
  12. Kringelbach ML, Stein A, van Hartevelt TJ. The functional human neuroanatomy of food pleasure cycles. Physiol Behav. 2012;106(3):307-316. doi:10.1016/j.physbeh.2012.03.023
  14. Rajamäki TJ, Puolakka PA, Hietaharju A, Moilanen T, Jämsen E. Predictors of the use of analgesic drugs 1 year after joint replacement: a single-center analysis of 13,000 hip and knee replacements. Arthritis Res Ther. 2020;22(1):89. Published 2020 Apr 21. doi:10.1186/s13075-020-02184-1
  15. Crawford DA, Hurst JM, Morris MJ, Hobbs GR, Lombardi AV Jr, Berend KR. Impact of Morbid Obesity on Overnight Stay and Early Complications With Outpatient Arthroplasty. J Arthroplasty. 2020;35(9):2418-2422. doi:10.1016/j.arth.2020.04.098
  16. Hartford JM, Graw BP, Frosch DL. Perioperative Complications Stratified by Body Mass Index for the Direct Anterior Approach to Total Hip Arthroplasty. J Arthroplasty. 2020;35(9):2652-2657. doi:10.1016/j.arth.2020.04.018
  17. Tompkins G, Neighorn C, Li HF, et al. Extremes of body mass index have significant impact on complications, readmissions, and utilization of post-acute services after primary total hip arthroplasty. Bone Joint J. 2020;102-B(7_Supple_B):62-70. doi:10.1302/0301-620X.102B7.BJJ-2019-1527.R1
  18. Mohamed NS, Wilkie WA, Remily EA, et al. The Rise of Obesity among Total Knee Arthroplasty Patients [published online ahead of print, 2020 May 22]. J Knee Surg. 2020;10.1055/s-0040-1710566. doi:10.1055/s-0040-1710566
  19. Heo SM, Harris I, Naylor J, Lewin AM. Complications to 6 months following total hip or knee arthroplasty: observations from an Australian clinical outcomes registry. BMC Musculoskelet Disord. 2020;21(1):602. Published 2020 Sep 10. doi:10.1186/s12891-020-03612-8
  20. Shearer J, Agius L, Burke N, Rahardja R, Young SW. BMI is a Better Predictor of Periprosthetic Joint Infection Risk Than Local Measures of Adipose Tissue After TKA. J Arthroplasty. 2020;35(6S):S313-S318. doi:10.1016/j.arth.2020.01.048
Conservative Treatment Options Before Joint Replacement Surgery

Conservative Treatment Options Before Joint Replacement Surgery

By | Bones of the Bay

By Katheryne “Kat” Downes, PhD, MPH
Director of Health Research, Outcomes & Evaluation
Florida Orthopaedic Institute

This post is not a substitute or replacement for professional medical advice. If you have any questions about your medical condition or treatment, please seek the advice of your doctor.

Each year, there are roughly 450,000 total hip replacements and 650,000 total knee replacements in the US. With our aging population, it is estimated that by 2030, there will be 635,000 total hip replacements and 1.28 million total knee replacements yearly, and these numbers are expected to continue to rise over the next few decades. 1

In other words, a LOT of people get joint replacements nowadays!

If you have really bad pain in your hips or knees, a joint replacement can really improve your quality of life, but the timing of seeing an orthopedic surgeon and the timing of the surgery itself are important. Why?

Well, if you are starting to have joint pain, it is a good idea to come in to see an orthopedic doctor sooner, rather than later. You will have more choices when your joints have only a little damage and getting treatment early may give you more time before you will need a joint replacement. (Keep reading to learn more about conservative treatment options).

As for the timing of your surgery, there are a couple of different things to think about:

Your age: If you have your hip or knee replaced, your new joint will likely be made of things like metal, plastics, and/or ceramics. Like any other machine parts, your joint can wear down over time and need to be replaced. Studies show that patients should expect their total hip and total knee replacements to last up to 25 years. 2-3

So, if you are 40 when you have your first surgery, you will probably need another one when you are around 65 years old. This does not mean that you should not have surgery if you are only 40 and in a lot of pain, but your age should be part of the decision.

Planning for time off to recover from surgery and getting the help you will need:
Joint replacement is also not a minor surgery. It takes about 6 months to heal from a total knee replacement. But it will often be a year or more before you feel completely “back to normal.” This means that you must plan ahead to make sure you can take time off. You also need to make sure you will have the help you need at home during your early recovery.

Timing surgery to get the most benefit:

Finally, when it comes to joint replacement, patients seem to feel best after surgery when they wait until their joint is really bothering them a lot. This may seem strange, but it makes sense when you think about it: you are more likely to notice a big change if you go from a painful joint to a brand new one!

So, what can you do now if you are not ready for a joint replacement?

If your doctor thinks you are not yet a good candidate for joint replacement (or you are not ready to get one yet), they will talk to you about “conservative treatment options” such as conservative treatment options before joint replacement surgery. These are things that tend to be lower risk and less invasive and can provide some relief for a while.

It is a good idea to try the easiest things first (like exercise, stretching, hot/cold packs) before trying any sort of medication or injections. Here are some of the options your doctor may talk to you about:

* Glucosamine and chondroitin are common over-the-counter (OTC) supplements for osteoarthritis. The scientific evidence has been mixed as to whether these supplements help or not. Some studies show that chondroitin can reduce pain and improve function better than a placebo and that glucosamine can reduce stiffness. Other studies show the opposite: taking these supplements does not help more than taking anything at all. 4-6 As always, talk to your doctor before starting any new medications (including supplements) to make sure it is safe.

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