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Haddad v. Pagnano: Simultaneous Bilateral TKA: Are They Safe, Effective & Cost-Efficient?

OTW Staff • Wed, May 3rd, 2017

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This week’s Orthopaedic Crossfire® debate was part of the 17th Annual Current Concepts in Joint Replacement® (CCJR), Spring meeting, which took place in Las Vegas this past May. This week’s topic is “Simultaneous Bilateral TKA: Safe, Effective & Cost-Efficient.” For the proposition Fares S. Haddad, M.D., F.R.C.S., University College Hospital, London, United Kingdom. Opposing is Mark W. Pagnano, M.D., Mayo Clinic, Rochester, Minnesota. Moderating is Joshua J. Jacobs, M.D., Rush University Medical Center, Chicago, Illinois.

Mr. Haddad: The real issue here is that about one-fifth of our patients undergoing total knee replacement have severe pain in the other knee and one in ten or more need the other side replaced fairly quickly. I would put it to you that the right patient will benefit greatly from simultaneous bilateral total knee replacement and that it’s an effective and cost efficient procedure.

Mark Pagnano will paint a totally opposite picture, but deep down he will broadly agree with me because the reality here is that the literature is weak and can support either argument. But the world has moved on. With modern screening, optimization techniques, careful patient selection and efficient surgery, bilateral simultaneous arthroplasty is a very viable option. These patients walk into my clinic all the time and they prefer to have both knees done at the same time. They get one admission to the hospital, one anesthetic, they have a faster overall recovery, reduced costs, the same functional gain and overall, because they’re only exposed to one surgery, they have lower risks.

Let’s look at a number of papers. Clinical outcomes across the literature…whichever outcome you look at is positive for simultaneous bilateral TKA. The majority of patients would do the same thing again. More recent papers are more likely to be positive and often when we look at the second knee and compare the outcomes, the bilateral looks better. Survivorship is the same or better at 7 years, 10 years, or 15 years.

Cost is a big issue for us. In reality simultaneous bilateral is cheaper overall. Some good work from Kevin Bozic and others suggest this is a cheap way to go for the healthcare system.

The big concern is complications. In reality, there is a cardiovascular comorbidity associated with it, but we can pick those patients out pretty easily.

The problem is if you’re going to stage bilateral knee replacements, you’re going to have a dilemma because the risk is high for thromboembolic and other complications if you proceed. Some people say within the first three months, other say within the first year.

The literature here is very weak and there is no Level 1 data. So that’s why the argument will live on. But is there consensus? Because when the literature is weak, we tend to go to consensus and the reality is there has been one consensus document, but that hasn’t moved us much further forward.

I thought I would share with you some data from our institution. We’ve traditionally done this procedure in non-ambulators and those with severe fixed deformities or in cases where staging is impractical or the patients have really wanted it for social or professional reasons. We’ve been very cautious in diabetics and those with cardiovascular disease, as you might expect. In reality, there are many good candidates. We did a matched case series looking at 80 bilateral simultaneous and 160 staged and I recognized straight away that there is a selection bias here because we’ve picked the fitter patients for the bilaterals and we’ve compared them at short and medium term.

Demographically they’re pretty similar groups because we’ve matched them from the database. We then started looking at the perioperative data, length of stay is, of course, greater for the bilaterals, but then again they only have one admission and you’ve got to multiply the staged by two. Transfusions are greater…we expect that. And we discharge more of them to inpatient facilities. But the other complications really are not increased significantly and there’s no difference in clinical metrics or radiographic outcomes.

At a minimum of five years, the outcomes are outstanding in the bilateral group and very much the same as the unilaterals. So while this is a screened cohort, we’ve seen comparable perioperative medium term outcomes. We’ve seen high satisfaction rates and low overall costs. I’ll put it to you that there is a continued role for simultaneous bilateral total knee replacement if you select the appropriate patients.

Dr. Pagnano: I’ll make the case against bilateral total knee arthroplasty in 2016. .

Bilateral total knee replacement, as you just heard, certainly has a number of different benefits that are available to patients and to surgeons. The patient and surgeon convenience factors. Thoughts on reduced healthcare costs. Because of these, this topic has been a source of debate for more than three decades. As Mr. Haddad suggested, it will continue probably for the foreseeable future.

The question does focus on the risks. Which patients are at high risk? Are the risks the same in all patients? Can specific selection criteria be appropriately identified and then acted on in a way that minimizes that risk? And finally, who decides bilateral or unilateral? Is it the patient? The surgeon? The healthcare system?

I think what we can do here is maybe think about this problem in a slightly different way than it has been in the past. I think that’s to think about the difference between relative risk and absolute risk. When the data is pooled, there is little doubt that the relative risk of certain complications is 1.5-5 times higher with bilateral simultaneous total knee replacement, than it is with unilateral knee replacement.

At the same time the absolute risk with any complication remains fairly low for the bilateral patients. Probably 96% of patients are going to get through a bilateral knee replacement without any complication.

Which way of interpreting the data resonates with you or me as a surgeon then, has a key influence on how we make this determination. And it has an influence on the patient as well. When you present relative risk data it seems alarming—1.5 to 5 times higher. When you use absolute risk data, it’s seems like it’s a low risk and an easy decision.

In addition, as you’ve heard, there’s a whole variety of different things over the years that have made discussion of this topic very difficult. Just the definition of bilateral total knee replacement. Does this mean staged operations, or are we only talking about simultaneous? Even if we do simultaneous, is it simultaneous with sequential surgery and monitoring in between? If you stage it is it at the same hospitalization or at various intervals?

Most of the data that is out there compares bilateral simultaneous total knees to unilateral total knees and that is confounding. There are few staged versus simultaneous studies. There are no randomized clinical studies that have done to date. We have to ask, “Are unilateral and bilateral patients really the same?” Is the selection biased for patient entry into any of these studies? The data completeness in many of these reports is sadly lacking.

What is clear is that the elderly, cardiovascular patient is at increased risk with bilateral total knee replacement. That goes back more than 25 years and is not really a subject of debate even in 2016.

We start to then say what age and what other medical comorbidities make a difference? We start to come down—80 years, 75, 70—have we really looked at 65 year olds? In addition to cardiovascular, what about pulmonary disease? What about other factors that might be out there?

If you pool data from huge numbers of studies that are out there, you can start to get a better assessment of the overall risks associated with bilateral total knee replacement. We pooled the data …50,000 bilateral staged operations versus 15,000 simultaneous bilaterals with 2.7 times higher incidence of death in the early post-operative period with simultaneous bilaterals. Again, the absolute risk is quite low, but the relative risk is 2.5 times higher.

We looked at DVT [deep vein thrombosis] and PE [pulmonary embolism], the DVT data is split probably because we use more aggressive pharmacologic agents in the simultaneous bilaterals. If we look at PE, PE is higher in the simultaneous bilateral patients. We look at cardiac events. If we pool the data for cardiac risk factors, they are certainly much higher in simultaneous than staged. Finally, confusion or neurologic issues—again, higher in the simultaneous bilaterals than in the staged ones.

So I think some patients can safely have simultaneous bilateral total knees. That’s the absolute risk issue. The risks are high despite the selection bias and the prognostic risk variables are really not very well determined. This then becomes a personal philosophy issue. There’s a value judgment that goes into how you value the relative risk versus the absolute risk and that can’t be quantified with scientific judgment alone. Some surgeons and patients will decide that the absolute risk is low enough to offset the higher relative risk and be comfortable with simultaneous bilateral knee replacement, and others will not.

I rarely perform simultaneous bilateral total knee arthroplasty in 2016. And only about 10% of total knees done at Mayo Clinic are bilateral. Thank you.

Moderator Jacobs: Thanks Mark. Great arguments. So we’ll turn to Fares. Mark has presented us with what looks like some compelling data about the higher relative risk of a number of systemic complications. How do you respond?

Mr. Haddad: Well, I’m not worried to operate on anyone at all to be honest. In reality there are two key factors there. The first one is that a lot of the data is old data and there is a cohort effect in that we are now much better at optimizing our patients; better at doing the surgery, and those risks should be decreasing. The other real effect is when we’re doing the comparisons, you’re comparing the effect of two operations done at the same time compared to the effect of one operation and people are forgetting to add the fact that the patient will then undergo a second surgery. I accept that it’s not A + B, but there is going to be an additive risk to that second operation, which is never put into the aggregated pooled data. So I would say that in the right patient, relative risk is not that increased.

Moderator Jacobs: Mark, I’ll give you a chance to respond, but I will emphasize a point that Fares made. When you did your forest plots, which is a great way to look at this data, can we rely on cases done in the 1980s and 1990s, which was a number of those since our techniques have changed so dramatically?

Dr. Pagnano: Yes, I think when you look at all of these different risks, particularly the mortality risk, we really haven’t made a huge impact on the mortality risk with knee replacement, even in the last 20 years. So, the risk of mortality is low, but that’s certainly the most dramatic and disconcerting problem for you and me as surgeons, but also obviously for the patients. I don’t think those numbers have changed dramatically. Similarly the PE rates, despite all the things we’ve done and changed since the 1990s, not dramatically different today than 20 years ago. I think the data, particularly when it’s pooled like that, is still reasonable.

Moderator Jacobs: I think I would sum it up by saying that it seems to be a personal philosophy based on the individual surgeon, and we hope we have better data going forward on who we can do this procedure on more safely.

Please visit to register for the 2017 CCJR Spring Meeting, – May 21 - 24 in Las Vegas.

Senior Editor: Jay D. Mabrey, M.D., whose 35 year career in orthopedics included residency at Duke University Medical Center, service in the United States Army Medical Corps, Fellowship at the Hospital for Special Surgery and a long, distinguished career at Baylor University Medical Center where, in addition to his overall leadership at that institution, developed the Joint Wellness Program that helped patients get up after surgery more quickly, developed the first virtual reality surgical simulator for knee arthroscopy and chaired the FDA Orthopaedic Device Panel, is Orthopedics This Week’s newest contributing writer and editor.

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