Knee Replacement: An Overview
Guest: Dr. Harry Demos – Orthopedic Surgery
Host: Dr. Linda Austin –
Dr. Linda Austin: I’m Dr.
Linda Austin. I’m interviewing Dr. Harry
Demos who is Assistant Professor of Orthopedics here at the medical university. Dr. Demos, let’s talk about knee replacement
surgery. Who’s a good candidate for that
Dr. Harry Demos: Knee
replacement is an operation that is designed for people who are having
lifestyle-limiting pain in their knee from arthritis. So, I don’t put age limitations on that. But, in general, if you look at the patient
population that develops arthritis in their knees, usually it’s in the mid-40s
on up. We do see some younger patients
that have rheumatoid arthritis that sometimes need a replacement at a younger
age. But, in general, it’s very commonly
seen in the high school football player who tore his ACL playing football and
limped on his knee for years and then developed arthritis from having an ACL
deficient knee over a 20-year period.
So, we’re seeing them at around 40 years old, for the younger patients.
Now, as patients get older, there are many patients that we don’t
see until they get into their 60s or 70s that developed arthritis just over
time. But there are two distinct
populations, usually in the 40-50 and then in the 60-70 age population, we see
a lot of those patients with arthritis.
Dr. Linda Austin: Are you
ever too old for knee replacement?
Dr. Harry Demos: It really
depends more on physiologic age than chronologic age. I’ve done knee replacements on 90-year-olds
and beyond that have done incredibly well.
A lot of that has to do with what it takes to be 90 years old and still
active and still want to have a knee replacement. Those patients are usually pretty fit, and
they’re much healthier than many of the 60-year-olds that end up needing a knee
replacement. So, I don’t think there’s
an absolute cut-off for being too old.
It really depends on medical co-morbidities and other problems that
people have as to whether or not they’re good candidates for this.
Dr. Linda Austin: How many
of these do you do a year?
Dr. Harry Demos: About
100-150 a year.
Dr. Linda Austin: It must
be a very familiar procedure for you.
Dr. Harry Demos: It
is. It’s something that I do a lot
of. I’m fellowship-trained in hip and
knee replacement surgery, so it is something that I do frequently. It’s the vast majority of my practice.
Dr. Linda Austin: What are
some of the most common concerns patients have going into this surgery? What are the questions you get asked?
Dr. Harry Demos: With knee
replacement, in particular, I always talk to them about the complications and
everything else that can potentially happen, but also about the benefits. Everybody wants to know, what can I do and
when can I do it? And, in general, for
knee replacement, I’d want to get people back to doing what they want to do,
including recreational activities, playing golf, playing some tennis. We do have one patient that has won many
championships, even at the national level, in her bracket playing tennis. And that’s part of the reason why we do joint
replacement surgery, to get people back to an active lifestyle.
Dr. Linda Austin: How about
really physical things, football, soccer, basketball? Are contact sports a problem?
Dr. Harry Demos: I think
that contact sports are probably not appropriate. And most patients who are seeking joint
replacement surgery are past the age of doing contact sports. The things you worry about with contact
sports are fractures around the prosthesis.
I don’t think they’re going to damage the prosthesis or pull the
prosthesis loose. But, these are
artificial implants and they do see wear-and-tear just like any artificial substance
would when it’s put through a tremendous amount of motion, a tremendous amount
I often use the analogy that it’s like the tires on your car. You don’t put a set of new tires on your car
to park it in the driveway. You put a
new set of tires on your car so you can drive your car. And you want to drive your car, and you can
drive it down the highway, and you can do what you need to do in your car, but
it doesn’t mean that you slam on the brakes every time you come to a stoplight
and take every corner at 70 miles an hour.
So, the knee replacement is kind of the same way. I think you need to be reasonable about what
you’re doing. I don’t impose significant
activity limitations on people. I want them
to get back to doing what they want to do, and there are not too many things
that are completely out of the question.
I would say contact sports are not the best idea.
Dr. Linda Austin: How long
is the recovery period after surgery?
Dr. Harry Demos: Knee
replacement takes a little bit longer to recover from than hip replacement, and
that’s one of the frustrations that we’ve had with knee replacement for many
years. I think we’ve improved that a
lot. And a lot of that came out of the
minimally invasive surgery controversies, if you would, that have come around
recently. I think the biggest thing that
came out of minimally invasive surgery is an improvement in perioperative pain
management and an improvement in physical therapy, not necessarily the length
of the incision. And by improving the
level of pain earlier, we’re able to get people back to doing things quicker.
But I tell people that it takes me about two hours to get them in
and out of the operating room and get this procedure done, and it’ll take them
about two months of doing their job, which is the physical therapy and the work
to make this thing as good as it can possibly be.
Dr. Linda Austin: What are
the controversies in knee replacement surgery these days?
Dr. Harry Demos: There have
always been controversies in all types of joint replacement, and knee
replacement. Probably the biggest is minimally
invasive surgery. There was a lot of
marketing around minimally invasive surgery a couple of years ago. The hype has calmed down a little bit as some
complications, problems, and things came out.
I think a lot of surgeons not only altered the surgical technique but
also altered the implants in order to accommodate for minimally invasive
surgery, and that did lead to an increased complication rate in some
studies. So, that’s one controversy. But I think a lot of that has cooled down a
little bit now that there’s not quite as much marketing towards minimally
invasive surgery. I think what’s
important is to do the operation through the smallest incision that we can, but
still do the operation right, that’s going to last the longest period of time.
Other controversies, there are some controversies about whether we
should save the posterior cruciate ligament or sacrifice it. That’s been an ongoing controversy for 15, 20
years. And the reason why it hasn’t been
resolved is that there’s really not that much of a difference. There’s a controversy as to whether the
platform should rotate or not, whether it should be a fixed platform, cement
versus no cement. There are many controversies and many things that some
people are very set on saying that this is the way that it should be and the
only way it should be. But there’s
certainly data to support the other ways of doing things as well.
Austin: Dr. Demos, thanks so much for
talking with us today.
Dr. Harry Demos: Thank you very much.
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