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

By May 6, 2021March 25th, 2022Announcements, Bones of the Bay
Total Joint Replacement

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.

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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.