Artificial Hip Replacement: An Overview

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Artificial Hip Replacement: An Overview




Guest:  Dr. Harry Demos – Orthopedic Surgery

Host:  Dr. Linda Austin – Psychiatry


Dr. Linda Austin:  I’m Dr. Linda Austin.  I’m talking today with Dr. Harry Demos who is an orthopedist and Assistant Professor of Orthopedics here at the Medical University of South Carolina.  Dr. Demos, you’re an expert in artificial hip replacement.


Dr. Harry Demos:  Correct.


Dr. Linda Austin:  Let’s talk about that.  Who is a good candidate for that surgery?


Dr. Harry Demos:  It used to be that the ideal candidate for hip replacement was an older sedentary patient, basically, a retired patient who wanted to be able to remain ambulatory and couldn’t because of lifestyle-limiting pain.  We’re now finding that there are more and more younger patients that are good candidates for hip replacement surgery, the young active patient, the mother or father with young children at home who still wants to be able to keep up with their children or still wants to be able to lead a productive life in the workforce, rather than just retired or sedentary patients.


There are two issues that have caused that.  One is that people seem to be getting arthritis at younger ages because of more wear-and-tear on their joints, working harder, playing harder, and other conditions that lead to arthritis.  The other is that joint replacement wasn’t always an option for those patients.  Joint replacement would fail in the younger patient.  The results of joint replacement in younger patients were no where near as good as they were in older patients.  And for that reason, many people avoided doing joint replacements in younger patients, whereas now we’re finding that we can do it in younger patients and keep them active.


Dr. Linda Austin:  I would guess that, in the case of, let’s say, post-auto accident, you might end up doing replacements in very young patients.  But let’s say, the arthritic patient, what’s the youngest age at which folks may start to need to think about a joint replacement?


Dr. Harry Demos:  The only reason to think about a joint replacement is if the pain becomes so severe that you can’t do what you want to do in life.  And that can be from a number of different causes, not just degenerative arthritis, but childhood abnormalities that are manifesting themselves later on in life, the dysplastic hip or the child who had perthes that is now developing arthritis at a relatively young age, several other childhood conditions that lead to early hip arthritis.  The majority of the ones that we see in this part of the country are usually from avascular necrosis, which happens for a variety of reasons, including prednisone use.


Dr. Linda Austin:  Steroid use?


Dr. Harry Demos:  Right, correct, steroid use, or alcohol, or even post-traumatic.  There are many different causes.  It’s also seen very commonly in patients that have lupus or other inflammatory-type autoimmune conditions. 


Dr. Linda Austin:  Now, just to explain a little bit more, avascular, of course, means that there is not good blood supply, right?


Dr. Harry Demos:  Correct.


Dr. Linda Austin:  And necrosis means that the joint starts to actually die as a result?


Dr. Harry Demos:  Correct.  The ball of the femur, the femoral head, loses its blood supply and then collapses, so it’s not a round ball in a round socket anymore.  And that leads to arthritis in the joint because of the weight-bearing forces, the concentrated forces, that are going across it.  So, it becomes very painful.  Avascular necrosis itself is painful.  But, once it collapses and you develop arthritis, it is a painful condition.  And it’s one that is not going to get better on its own. 


My thought on that is, for the young active patient who wants to remain in the workforce, to tell that patient, you’re too young for a joint replacement, come back when you’re 70, and is really not a good option anymore.  We want those patients to continue to do what they want to do.


Dr. Linda Austin:  So, are you doing them, sometimes, for patients in their, say, 30s?


Dr. Harry Demos:  Usually, it starts off in about the 40s.  That’s when we really see people starting to have problems from things that started off earlier.  I have operated on patients in their teens with joint replacement surgery.  And that’s usually for inflammatory conditions, like rheumatoid arthritis.


The majority of the degenerative processes start to happen in the early 40s, usually not in the 30s.  And, obviously, if there’s anything we can do preserve the hip joint, if we can do a correction of whatever problem to preserve it before arthritis starts, we can do that as well.


Dr. Linda Austin:  Now, if someone is in their 40’s and otherwise they’re pretty healthy and pretty active, how long can a hip replacement last?


Dr. Harry Demos:  That’s a good question and it’s one that we really don’t know, entirely, the answer to.  If we look back at hip replacement from 30 years ago, we knew that hip replacement in the young, under 50, population had about 50 percent survival at 15 to 20 years.  Only about 50 percent of those joints were still good for 15 to 20 years.  But there have been a lot of advances in bearing surfaces.  There have been a lot of advances in bony end-growth of the implants, to the point where, now, even looking back at ones we were doing 15 years ago, we’ve got about 95  to 99 percent survival of the implants at 15 years. 


The problem with joint replacement is it takes a long time to know how good what we’re putting in now is going to last because the latest and greatest thing on the market is not always the best.  It takes 15, 20 years before we know whether that’s better than what we’ve been doing before.  So, we can simulate things in the lab, but it’s hard to know how that transfers from the lab to actual patient survival of the implant.  


Dr. Linda Austin:  What are some of the debates now in the field?  I know surgeons often are kind of a contentious group and everybody wants to figure out the best way.  So, what are some of the debates going on in the field about hip surgery?


Dr. Harry Demos:  There are always a lot of debates about hip surgery.  And, even within a group of surgeons, you’ll find debates of some surgeons who do it through an anterior approach, some who do hip replacement through a posterior approach, some who do it through two incisions.  There are multiple ways of doing things.  I’d say the biggest debates now are the minimally invasive controversies that came out from several years ago, about the two-incision technique with minimally invasive surgery and the complications associated with that.  There are some improved outcomes by being less invasive but we really did find a lot of complication from people trying to alter the technique too much.  So, that’s one of the big debates that’s going on now.


The second is still the ongoing debate about bearing surfaces.  We have several different bearing surfaces that we can do in young active people, whether it’s cross-linked polyethylene, ceramic bearing surfaces, or metal-on-metal bearing surfaces.  There are some surgeons who use all three.  There are some surgeons who stick with just one.  And it’s very controversial as to which one is the best.  I think that all three are much better than what we were doing 20 years ago, and it’s what’s really taken us to the next level of being able to offer this to younger patients.


Dr. Linda Austin:  How long does the procedure take?


Dr. Harry Demos:  The procedure itself takes between one and two hours in the operating room.  The actual OR (operating room) time is a little bit longer than that by the time you get positioned and catheters and lines and anesthesia, and everything else, and then wake up and get turned back onto your bed with your dressing and everything.  But the procedure itself can usually be done in just a little bit over an hour.  We generally keep people in the hospital for about three nights.  That’s our average length of stay, about three nights in the hospital afterwards. 


There have been some studies looking at outpatient total hip replacement and some where people just stay overnight.  But, most complications, if they occur, occur on the second postoperative day.  We feel it’s safer just to keep people in the hospital for three days, just to make sure they’re doing what they should be doing with therapy and make sure there aren’t going to be any complications.


Dr. Linda Austin:  How long before they can start walking again?


Dr. Harry Demos:  We have people walking the day after surgery.  Most patients are full weight-bearing on their joint as soon as they start to recover.  By the end of the third day, by the time they go home on the third day, we usually have people walking down the hall and going up and down stairs.  So, they’re pretty independent by the time they go home.  I usually tell people, it takes about six weeks to get to the point where they’re ready to go back to work, ready to go shopping, and ready to go to church, those kinds of things, drive a car, all that, is about a six-week recovery period.  That’s a little conservative for some people, but for other people who are more debilitated, they make take a little bit longer than that.


Dr. Linda Austin:  Dr. Demos, thanks so much for talking with us today.


Dr. Harry Demos:  Thank you.


If you have any questions about the services or programs offered at the Medical University of South Carolina or if you would like to schedule an appointment with one of our physicians, please call MUSC Health Connection:  (843) 792-1414.


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