Unicondylar Artificial Knee Replacement

Randale Sechrest: Hello, I'm Dr. Randale Sechrest, your host for eOrthopod.TV. Today I have as my guest Dr Ira Kirschenbaum. Dr Kirschenbaum is an orthopedic surgeon who practices in Manhattan, New York. Dr Kirschenbaum did his medical school training at the Albert Einstein College of Medicine. From there he did an orthopedic residency at the Montefiore Hospital also associated with the Albert Einstein College of Medicine. Dr Kirschenbaum did a fellowship in joint replacement and joint reconstruction at the Rothman Institute in Philadelphia, Pennsylvania. Thanks for joining us today Ira.

Ira Kirschenbaum: Thank you. Also I am the Chairman of Orthopedics at Bronx-Lebanon Hospital, in Bronx, New York.

Randale Sechrest: Dr Kirschenbaum, what I thought we would discuss today is a part of a joint reconstruction or joint replacement and that is the Unicondylar knee replacement, that I think that if I understand you are an expert at performing this procedure?

Ira Kirschenbaum: Well I appreciate that, those kind of comments. I’ve done probably over a 600 Unicondylar or partial knee replacements since around 2001. So it spans a ten year history of early intervention and early adoption of this very, very good technology that fits certain patients extraordinarily well.

Randale Sechrest: Well, you know, we probably ought to take patients through what a unicondylar knee replacement is and distinguish that from what people might think of is a total knee replacement, where we replace essentially the whole surface of the knee including the kneecap, the end of the femur or the femoral condyles, and also the top portion of the lower bone, the tibia, in the leg or the tibial plateau. So, that’s what most people think of is a knee replacement. How does a unicondylar differ from that?

Ira Kirschenbaum: Well one of the major differences is - the name says it all, a partial knee replacement. Now some people like to think why should I get something partially replaced, when I should get the whole problem taken care of. And what I tell my patients is that there really is nothing partial about a partial knee replacement. It is a complete replacement of only the part of the knee that’s arthritic. In a way, a total knee replacement as you pointed out, has replacement of three parts of the knee. The inside of the knee between the thigh bone and the leg bone, the outside of the knee between the thigh bone and the leg bone and underneath the knee cap. Those are three compartments of the knee.

But it is very common for patients to only have arthritis in one of the three compartments. Therefore two of the compartments are completely normal. A partial knee replacement replaces only that part of the knee that is arthritic and allows you to keep the parts of your knee that are normal, which include the ligaments in the center of your knee. Total knee replacements remove those ligaments in the knee that are very important for normal functioning. By keeping the ligaments in a unicondylar or partial knee replacement allow you to maintain a high level of function. What I explain to patients frequently is that, think of your three parts of your knee as a part of your home. The kitchen, the living room and the dining room, if your kitchen was destroyed and you replaced your kitchen that would not be a partial home replacement, that would be a complete replacement of a part of your home that’s destroyed. And that’s the concept behind unicondylar or partial knee replacements.

Randale Sechrest: Well I think a lot of patients are going to ask, you know, what’s the benefit of a partial knee replacement? If you are leaving back behind the ligaments, I can understand that, but you are leaving behind surfaces that still might be prone to wearing out in the future, what do I gain by having just a partial knee replacement?

Ira Kirschenbaum: There are two advantages to a partial knee replacement. The first is that the function of a successful partial knee replacement is that at much higher level than the function of a total knee replacement. Patients who have total knee replacement at best 60% or so are extraordinarily satisfied and a higher number of partial knee replacement, not only in my experience, but in the literature have been shown to have a extraordinarily higher level of satisfaction. So your final result of a partial knee replacement is at a higher level of function.

The other advantage is that you don’t burn any bridges, in my opinion for future advances in joint replacement. Once you take out all the surfaces of the knee and replace them with metal and plastic, that is your salvage or your last procedure you can have. But when you do a partial knee replacement with much smaller percentage of the surface replaced, imagine five or six years from now, we start having cartilage replacements you may not burn a bridge in having to replace other parts of your knee. The studies have shown that only 5% of patients who have had partial knee replacements get failure due to the rest of the knee arthritis getting worse. So for a 5% risk of that happening, you get the advantage of a superior functional result.

Randale Sechrest: Now let’s talk a little bit about that function and you know I think a lot of people think that if they only have a partial knee replacement then perhaps that’s going to allow them to do more strenuous activities, activities like playing tennis for example or perhaps something that causes impact on the knee such as jogging and that sort of stuff. Do you allow your patients who have partial knee replacement to do these activities and where do you draw the line?

Ira Kirschenbaum: I draw the line for a partial knee replacement at exactly the same place I draw the line at a total knee replacement. What I allow them to do and what they feel they can do are two different things. Just like a total knee replacement, a partial knee replacement is metal and plastic. And it is never as strong as the day you put it in. And the only thing that can happen to any metal and plastic over time is wear. So the better you treat it, the less impact you allow it, the longer it’s going to last. It's a trade off. We like to say sometimes don’t do the crime if you can’t pay the time.

If you’re going to start jogging and if you got start playing singles tennis five days a week, you are going to wear down a total knee or a partial knee a and need a second operation. So I actually use the same activity restrictions in a partial knee as I do in the total knee. Now I allow patients to play tennis once a week, I give them some advice, they will play at a higher level meaning more flexibility, more motion and better what we call proprioception, which is the sense of your knee and space while they are playing. But I don’t let them play any harder than I would a total knee. But I think it’s very important for patients to keep in mind that a joint replacement whether partial or a total should have the same activity restrictions especially when related to how long you want it to last.

Randale Sechrest: Well, let’s clarify some other things for patients and I think this is in some ways information that patients maybe hearing out in the marketplace, their friends maybe talking with them. They may be even seeing ads on TV and in the newspapers about minimally invasive surgeries. And I think that this partial knee replacement is in some ways confused with a notion of minimally invasive surgery. Can you clarify that for patients in terms of, is a partial knee replacement, is a unicondylar knee replacement considered minimally invasive? And what are the advantage of minimally invasive knee surgery?

Ira Kirschenbaum: It’s a great question because in my opinion a unicondylar or a partial knee replacement is truly minimally invasive knee replacement surgery. Besides being only a two inch incision, you don’t take out any ligaments and you’re really replacing the surface with a very small amount of metal and plastic. On the other hand, historically people think of minimally invasive surgery as a small incision and less trauma to the tissues. I could make an argument that there is almost no such thing as a minimally invasive total knee replacement. Because even if you do it through a small incision of a knee replacement, you are still replacing the same amount of the knee. So you are completely replacing all the surfaces.

There is nothing particularly minimally invasive about a total knee replacement, but by replacing less of the tissue, a partial knee replacement or unicondylar is truly a minimally invasive knee replacement procedure, while a minimally invasive total knee replacement should really be called a minimal incision or a minimal trauma to the tissue. But it’s still very invasive procedure a total knee replacement, one that is needed for pain relief when all three parts are destroyed, but there is nothing minimally invasive that about any type of total knee replacement, while a partial knee is truly minimally invasive.

Randale Sechrest: Let’s talk a little bit about how you make the decision whether someone is a candidate for a unicondylar knee replacement? And how that differs from the patient that you may look at and say, well this person is not a candidate for the unicondylar they need a total knee replacement. What do you go through as a part of your diagnostic procedures, your evaluation that helps you make that decision? Can you take a patient through it for me?

Ira Kirschenbaum: Sure, I think the first thing is the history, the second part, physical examination, the third part, the X-rays and the last part, a very extensive informed discussion with the patient. Those are the four pieces. So let’s go over them one at a time. First is the history. This is not a procedure, where the physician looks at an X-ray and just decides what you get. This is a procedure that is a discussion and an exploration with your surgeon about what’s best for you. It starts off with a history of where is the pain and what I like to hear for a partial knee replacement is, the pain is only here. Here being one compartment of the knee where that’s underneath the knee cap, whether it’s between the femur and the tibia, on the inside call the medial partial knee or medial unicondylar or on the outside of the knee, which is called the lateral. I like to hear that the pain is only here.

When I start hearing from a patient that the pain is everywhere, it’s in the back, it’s on the side, it’s all throughout the knee, it sometimes doesn’t matter what the X-ray show, because if the patient is having significant pain in two or three parts of the knee, there is no way a procedure that replaces only one part is going to really take care of the pain. So my classic patient for a unicondylar partial knee replacement is someone who is complaining and being able to isolate the pain in one part of the knee. So that’s on the history I like to hear that and I ask a lot of questions about that - going up the down steps, rest pain, where is the pain, where is most of the discomfort? That’s the first part.

The second part is the physical examination. And in a classic partial knee replacement patient, their tenderness and their entire deformity of the knee is isolated to one part. For example, when it’s on the inside of the knee, the patient may have some mild bowing or what we call a varus deformity, that’s a medical term and it means a bowing of the knee. And they will classically have the pain on the inside only. And they may have some discomfort in the rest of the knee, but primarily 90 percent of their pain is going to be in that one compartment.

The third part is I need the X-ray confirmation, that the arthritis is first of all present and the cause of the pain and there isn’t another reason non-orthopedic for the pain. But once I look at an X-ray and I see that the arthritis is restricted primarily to that one compartment, that’s my third part of the discussion.

And the last part is, the discussion with the patient once I’ve recommended a partial knee replacement, that they understand the limitations, that five percent of the patients or maybe a little bit more would go on to progress and need to conversion to a total knee replacement. And as they understand the trade-off of a slightly increased failure rate for the benefit of increased satisfaction, decreased pain, quicker recovery, and a better functional result. If they understand that, then all four of my components are met and a patient would be an excellent candidate.

Randale Sechrest: Now at that point, when you have that discussion with the patient and you’ve decided to move forward to doing the unicondylar knee, what do you have the patient do at that point? Is there any sort of preOp evaluation that you want the patient to have? Do they need to see their primary care physician? Do they need to do any special testing? Or are you ready to take them to the operating room at that point?

Ira Kirschenbaum: For me the orthopedic point of view, I am generally ready to take them in. Except for a preoperative patient education session where they would need a nurse practitioner or physician's assistant who would educate them about the hospital stay and what to expect postoperatively. There are many places, we used to do this or don’t do this much anymore who have a preoperative physical therapy appointment and that’s sometimes very helpful, it educates the patient as to the devices like a cane or crutches they would use and what exercises that they’ll be expected to do after surgery.

Probably the most important visit is with the primary care physician - whether that is with the family practitioner or an internist or whoever is their primary specialist, maybe it’s a cardiologist that if they have a cardiology problem. What we have done successfully is the following patient protocol or patient pathway. I ask them to see their primary care physician immediately. Not two weeks before the surgery, not a month before the surgery but right away, where I will have already communicated with the family practitioner or the internist that I plan to do this procedure on this patient.

And that’s important because while the patient may generally be healthy, the question is, are they healthy enough to undergo some type of significant procedure like a knee replacement. My colleagues in primary care may decide someone may have a stable heart problem or high blood pressure they’ve been following. But at this point in time since they will be going through some major surgery, now it’s a good time to get a nuclear stress test or an echocardiogram, which they would not normally have gotten at that time of the year. And some these tests take sometime to get, maybe they have to get insurance authorization or maybe they have to get some other type of wait, to wait for availability for certain tests.

So and we’ll sort of know what they’re going to find on these tests. So its -- interesting in that from the time I decide with the patient that we’re going to move ahead with the surgery, it sometimes takes as long as three to eight weeks to get them to the operating room, because we want to make sure they see their primary care doctor right away, so they have time to take care of certain medical issues and optimize them, get their blood pressure perfectly under control. Diabetes, very important to be completely under control. And this gives the primary care doctor some time to reevaluate some of the medical problems and the context of going forward with surgery. So we ask them to see their primary care doctor within a week after the decision for surgery and once we get a report from the primary care doctor where they stand, then we decide on the reasonable time to get the surgery.

Randale Sechrest: Now let’s talk a little bit about the surgery itself. Are you doing unicondylar knee replacements as an outpatient or is the patient spending one, two, three nights in the hospital?

Ira Kirschenbaum: The patient spend time in the hospital where we are, where I am here. And most of the reason for that is that usually is determined by what is the culture in the community. For example, some places like in Florida or warm weather places, where that everything is on a single ranch level, it’s very common to appropriately have partial knee replacements as an outpatient, meaning you would get the surgery and maybe even go home that day.

I find that in areas where people live in four-story walkups or difficult to reach elevator buildings, it’s a little more difficult to go home and it’s more common to have an average of one to three day hospital stay. And a hospital stay really depends upon the patient’s upper body strength. If they are generally a little weak, they are hard to lift themselves out and they may need the physical therapist to help them with that. From a medical point of view, they can actually go home that night or certainly the next day. Usually it’s from a mobility point of view that they don’t feel that they are able to go home. So I would say, safely a 24 hour stay would be what we shoot for. On average here at least in New York, it has to be two or three days. But an outpatient setting, I believe it’s very appropriate if the patients have good support services at home.

Randale Sechrest: Let’s talk a little bit about what to expect after the surgery? Are you allowing your patients to bear weight the very next day? Is this something that they’re going to have to stay on crutches or a walker and not put any weight on the leg that you’ve done the unicondylar replacement on?

Ira Kirschenbaum: In partial knee replacements and in total knee replacements, I have the same protocol, the patient puts all their weight on it the first day. And we allow them to move it as much they can the first day. Interestingly enough, we use a protocol which a number of surgeons around the country use, which is the use of various techniques to decrease the pain on the first day, the first 12 to 24 hours after surgery. And some of these techniques, which we use, and as I said, are used by many of my colleagues across the country, include injections of various long-acting, local anesthetics like long-acting Marcaine, which is an analgesic, like a pain reliever in the joint. Some people have added some steroid injection to that. I don’t, I use just the analgesic. We will use a cocktail with an anti-inflammatory medicine called Toradol mixed in with the Marcaine, some, we also use what’s called the femoral nerve block with the anesthesiologist - when the patient is in the operating room, gives an anesthetic to one of the major nerves going down to the knee, and for 24 hours the patients have very good pain relief from that. Interesting enough some of the pain that occurs after 24 hours is a bit worse than the first 24 hours because of these various techniques we use.

We also get fairly aggressive with analgesics with narcotic pain medicines, because no one should be in pain in the first few days. We allow the patients to walk right away. The pain, no matter what kind of surgery you get is very advanced. I think bone surgery in general is very painful. There is no question we could compare pain from total knee versus a partial knee, but that I find is not a comparison that’s worth doing, because no patient gets both procedures. They are going to get one or the other. The pain you have at the moment is the pain you’re experiencing. I have some patients with partial knee replacements who describe the pain is three out of 10, others describe it is eight or nine out of 10. What I do find remarkable in a partial knee replacement by about five or six days, the pain has diminished to a tremendous level, low level, a very low level and that level allows them to mobilize, to walk even more. And I’ve even had patients, one 86 year old patient of mine, who drove to my office at two weeks after I'd replaced both of her knees with partial knee replacements, she drove with her son in the car- in the passenger seat - to my office at actually 13 days after surgery. So it really, you can’t really do that without the types of knee surgery.

Randale Sechrest: Well that does bring up the question about recovery and as these patients recovery when do you feel that it’s safe enough for them to drive and when do you expect these patients to do certain milestones like further crutches away not need a cane to be able to do essentially all of the activities that they want to do. Can you give me somewhat of a time line that you expect patients to stick to?

Ira Kirschenbaum: Sure. I like to think of healing in three phases. The first is to heal the wound and recover from what is the general trauma that surgery does to the body. The second is motion, flexibility, and early activity and the third is getting back to all your normal activities of life. Those are the three phases. The first phase lasts about two weeks, which is healing the wound, getting your strength back from the incision, you’re going to feel tired, I encourage people to walk and do early motion and bending exercises, but I don’t encourage them to mainstream back into various parts of their life in the first couple of weeks.

From two weeks to six weeks is a time that I allow people to get back to some of their normal activities. Now every patient is different, sometimes either younger or older patients who go into the surgery with more vitality will be able to mainstream back into the activities a bit sooner. So I would say a majority of my patients are driving by about four weeks. They’re using a cane for the first four weeks for sure. Some people can get rid of the cane at two weeks in the home, but I encourage them to use the cane outside for at least one month. It’s not a rule, some people get rid of it. And by six weeks you should be about 90 to 95 percent better, 90 to 95 percent better. And again this is a majority of patients. I do have some patients who will walk into my office after a partial knee replacement at two weeks - not using a cane, walking beautifully. That’s not your average patient, that’s the patient you would show as your best example. The average patient is not doing that until about three to five weeks.

Randale Sechrest: Well, let’s talk about some things that sometimes patients and the surgeons don’t like to think about and that is what could go wrong. So what do you worry about as a surgeon at the time of the surgery? And then as the patient recovers and perhaps years down the road, what are the complications that you’re worried about as a surgeon and you watch for?

Ira Kirschenbaum: Infection for me would be the worst possible average complication. It’s very important that the physician takes a variety of steps to avoid that complication. First of all, it starts with preparing with the patient before surgery. There are patients where we have to make sure the nutrition is good and all the medical diseases, the diabetes and other chronic diseases are well controlled, because these contribute to an infection rate. The next thing is the use of antibiotics within an hour of the incision of the surgery and the third thing is the use of antibiotics in the cement. That is a little controversial in the sense that we don’t have a lot of evidence, but a lot of surgeons are putting antibiotics in the cement, which attaches the joint replacement to the bone to hopefully decrease infection rate.

The second complication that I worry about, which is not usually thought of as a complication, which is the patient not getting better, not getting the expected pain relief. I know that’s not truly thought of as a complication. But whether it’s a partial knee replacement or a total knee replacement, a certain number of patients just don’t get better and don’t feel the expected pain relief. And that’s why it’s important to do everything you can in motion, decrease the swelling, and educate the patient on how they could improve their result to decrease the pain down the line, because I don’t want a complication such knee stiffness to give them pain and continued pain after the surgery.

So those are the two major things I worry about. Other complications that do happen, people can get blood clots in the legs that can travel to their lungs. Although all patients in a partial knee replacement get their blood thinned with various medications, so that is a much less common complication that we’ve had. In the operating room in good hands, you’re not going to get many complications that people worry about. You’re not going to get the bone fracturing or ligaments cut unnecessarily, those generally should not happen in good hands. So I don’t usually worry about that, but I do discuss it with the patient as possibilities, but they would be extremely rare with an experienced surgeon.

Randale Sechrest: Well I think long-term, what’s the long-term prognosis for a unicondylar knee replacement. You know, I think a lot of people are interested in asking, well doc how long is this going to last me and what are my options when this wears out? Can you give us some enlightment from that standpoint?

Ira Kirschenbaum: Approximately, 10 years after we implant a partial knee replacement, if I did a hundred of them in one year, 10 years from now 80 to 85 should still be around. Now when I say that’s to the patients is interesting they sometimes say, so you’re telling me it last 10 years. I’m saying, no. At 10 years, if I did a 100 partial knee replacements, 80 to 85 would still be around. If you’re in the group that’s still around, you have succeeded and you haven’t failed. If you’re in the group that failed, then there would be other options that we would have to go through. It’s a risk factor. If you smoke, you won’t get lung cancer, but you’re at higher risk.

So you have about an 80 to 85 percent chance of it still being around at 10 years. At about 15 years, it begins to drop to much lower because the metal and plastic tend to accelerate their wear in later years. So that’s the first question I answer, which is the general longevity. You could expect an 80 to 85 percent chance of it lasting approximately 10 years. If your partial knee replacement fails, the first question we have to ask is, how did it failed? Did the plastic wear out? That could be one reason. Did the arthritis in the rest of the knee catch up and advance? That could another reason. Or did the metal implant get lose loose, get lose loose from the bone, did the metal implant loosen in it’s attachment to the bone. So the question is, if the rest of the arthritis or the rest of the knee developed arthritis, then you would have to convert the partial knee replacement to a total knee replacement.

Technically, if just the plastic that wore out and it is what’s called the modular knee replacement you could generally put a new plastic in, although that is not a common mode of failure. Once the plastic wears, chances are that debri would cause the rest of the knee to have failure and it would have to go on to a total knee replacement. And if the metal loosens from the bone then you would certainly have to revise that with some form of a total knee replacement. So in general, failures on partial knee replacement get converted to total knee replacement. You would not replace a partial knee or a unicondylar knee with another unicondylar knee. It just hasn’t been my experience that the failures of partial knee replacements allow you that option.

Randale Sechrest: You know, that brings up an interesting question and the question is this. You know, I think most surgeons feel that when you, like in the old days when you did an artificial knee replacement, a total knee artificial replacement, that the first, the primary artificial replacement that you did was always going to be far better than if you went back in and replaced it with what we would call a revision. The total knee got loose wore out and then you went back and did a second total knee where you revised the old total knee into a new unit. That was always considered far less successful than that first primary total knee.

Can you give me some insight in terms of what the success rate for converting a unicondylar, let’s say the unicondylar knee wore out at the 10th year and you were sitting down with the patient and saying we’re going to convert you to a full total knee replacement. How good is that compared to doing a primary total knee replacement versus what some people would say is a less successful operation at doing that second total knee?

Ira Kirschenbaum: I agree with you that a revising a total knee into a second total knee, you really go down a number of levels of function, which is actually one of the reasons why I am very strong proponent of partial knee replacements, especially in patients who are expected to possibly wear out a knee replacement in their lifetime. A total knee replacement has about a 1 percent failure rate as well. So at 10 years, 90 percent of them are around. And a revision of a total knee replacement is a very unsatisfying procedure.

A revision of a partial knee replacement into a primary knee replacement. In other words taking a partial unicondylar knee replacement and then taking that out and putting at a total knee replacement, in my experience, they are nearly as good, maybe as good as a primary total knee replacement. Now it’s hard to really compare them because people each person is different. But I have revised some of my own over the last 10 years and people who have failed partial knee replacements from other people who go to me because of my expertise in this, and I have found that it is not a difference, and approaches a primary knee replacement. So I like to think if a person can make a partial knee replacement last 12 years and then convert it to a primary total knee replacement that could last maybe 10 to 14 or 15 years, you’re much better off than a total knee replacement you had to get revised to a revision.

I consider failure of a partial knee replacement because the rest of the knee got arthritis to be equal in success when I convert that to a total knee replacement and compare that to a primary total knee replacement. On the other hand, if a partial knee replacement failed because of a collapse of the metal of the partial knee replacement into the bone causing bone loss, that would not be as satisfying a procedure. So the mode of failure of a partial knee replacement in a lot of ways determines the success of its revision to a total knee replacement. Since a majority of partial knee replacements would fail because of the rest of the knee getting arthritis at 10 or 14 years, that primary knee replacement is equal to a first time knee replacement. But if it failed because of a stress fracture of the bone or a collapse, or a loosening of the cement causing bone loss, you would probably lose some level of function.

Randale Sechrest: Well, I think that’s good information, I think that I really lends sort of evidence to the fact that in some cases we really prefer that partial knee replacement, when it can be done in younger people, because they’re going to have to depend on a longer span of time when that knee replacement needs to work for them. So if they can have a second procedure down the road 10 years 12 years and it’s just good as the first procedure would have been with a complete total knee replacement, that’s good news for younger patients who need a unicondylar knee replacement.

Ira Kirschenbaum: You know, I think it brings up the point that metal and plastic is metal and plastic. It has a certain life expectancy. A total knee replacement is not your total solution. And it has limitations in that when it does fail, revising it can be very complex. So you try to extend the life span and think of the patients entire continuum of life. A 56 year old who generally is healthy could live into their 80s. There is no expectation at that a total knee replacement will last that long. So, sequencing a number of procedures that would be less invasive first and then advancing in your invasiveness would be smarter for a patient’s entire lifespan.

Randale Sechrest: You know, I think that’s excellent advice and I think that’s definitely a huge advance in terms of a total knee replacement or any sort of joint replacement the knee in the last 30 years. That’s a huge advance for these patients. You know, Dr. Kirschenbaum this has been excellent information. I think patients are really going to get a lot of use out of this. Is there anything that we have not covered in this discussion that you feel like patients absolutely should know about unicondylar knee replacements?

Ira Kirschenbaum: Well, the only thing I would add to our whole discussion is that, there are surgeons in this country who do unicondylar and partial knee replacements, but there are a few that really don’t. And if you get an opinion from someone that does partial knee replacements and does total knee replacements both, you would probably get a more balanced opinion than if you went to somebody who just did total knee replacements. And I think patients have to understand to get educated opinions, you have to go to doctors who would do both procedures or have certain amount of experience with both procedures otherwise they won’t get a balanced view. You know, we would like to say sometimes if your only tool is a hammer, then everything starts to look like a nail.

If your surgeon who only does total knee replacements you would not be in a very good position to advice a patient whether or not to get a partial knee replacement. And that doesn’t mean that that surgeon isn’t the surgeon for you - the total knee surgeon. But if you get an opinion from someone that you feel maybe that could be another option, and that person only does totals, you would do well to get an opinion from a person does totals and partials. I do quite a lot of total knee replacements, in fact, a majority of my knee replacements are total knee replacements despite me doing quite a lot of partials. So I would like to feel that giving the patient a balanced view of what their options are is very important.

Randale Sechrest: Well, thanks. I think that is excellent advice and I think people will find that a very useful advice. So I want to thank you for joining us today. I look forward to future discussions on similar topics. Thanks for joining us.

Ira Kirschenbaum: Thank you Dr. Sechrest.