Total Hip Replacement 101

by Bob Kopac

This is an informational article about total hip replacements. When I learned that I needed to have hip replacements, I researched many options before deciding on a course of action. In case you or someone you know has a need for a hip replacement, I hope this information will help you make decisions on what type of device and what type of operation to get.

My hip replacement history:

November 14, 2002 is the day I went bionic. I had a THR (total hip replacement) of my right hip. I have a genetic birth defect of both hips called "acetabular dysplasia", which means my hips are partially formed. This condition led to severe osteoarthritis. I had my right hip replaced; I will have to have my left hip replaced in a few years.

Update: November 30, 2004

I had my left hip replaced. You can find additional information at the end of this article about that second surgery, including information about the new Fast-Track program at the Hospital for Special Surgery.

Update: June, 2007

Since my hip replacement surgeries, there is now another alternative: hip resurfacing, which I summarize below.

If you need a hip replacement, I recommend you do research and also get several doctor opinions. One doctor's surgery procedure may differ greatly from another doctor's. For example, one doctor told me that he would make a 14-inch incision and cut through my muscles to insert the prosthetic device. He said he would sew the muscles back together again. I decided that I did not want that particular procedure. While searching on the Internet, I learned about a minimally invasive procedure. I then searched for a surgeon who specialized in that procedure. Although the 14-inch incision method most likely would have resulted in a successful surgery, I was more comfortable with the minimally invasive surgery. However, that is a personal preference, and you may decide differently.

There are various hip replacement options:

Traditional

This involves a 12-to-14 inch cut of the thigh and may involve cutting through muscles. Time of surgery is 1.5 hours.

• Advantages: This procedure has been standard practice in the U.S. for years and has been performed on thousands upon thousands of patients. It is easier for the surgeon to operate; thus there are less complications.
• Disadvantages: Recovery time is much longer because of the muscle trauma from the cutting. Someone I know, age 49 and in good health, had the 14-inch cut procedure last year. Six weeks after the surgery, he was still on crutches. A German anesthetist friend of mind was astounded that U.S. doctors were still performing this "barbaric" procedure. She said that German surgeons perform minimally invasive surgery.

Minimally invasive surgery

Some doctors have performed this procedure for several years using traditional medical instruments. This procedure involves one 5-inch cut of the thigh and the spreading of the muscles. The procedure uses the same prosthetic device. Time of surgery is 1.5 hours. This is the procedure I chose, as I felt it was a good compromise between traditional surgery and a technique known as Minimally Invasive Solutions(tm) surgery (see below). The cost of my surgery (excluding anesthesia, hospital bills, etc.) was $15,000.

• Advantages: Minimal recovery time. Four days after the surgery, I left the hospital walking with a cane. I was able to go up and down stairs using a cane.
• Disadvantages: More difficult than the 12-to-14-inch cut, so there is greater chance of complications. Most doctors do not perform this procedure. Although there may be doctors who do this procedure in Poughkeepsie, I had my operation in New York City by Dr. Robert L. Buly at the Hospital for Special Surgery (HSS).

Minimally Invasive Solutions(tm) (MIS) Procedure for Total Hip Replacement.

For more information, see the Pace With Life web site. This is a two-incision, keyhole hip replacement procedure. This is a new style of experimental surgery that is at most a couple of years old. The patient usually walks out of the hospital the day after surgery. The surgery consists of two 2-inch incisions on either side of the leg. Using specialized equipment, the doctor spreads the muscles and inserts the same device as the traditional operation. The web site says time of surgery is 100 minutes, although a non-MIS doctor told me it is 4 hours. Zimmer Holdings, Inc. intends to create the Zimmer Minimally Invasive Solutions(tm) (MIS) Institute to train surgeons on this new process. The operation requires special medical tools and special training.

• Advantages: Radically minimal recovery time. Many patients have walked out of the hospital the day after surgery.
• Disadvantages: There are very few doctors trained in this new procedure and, as of 2002, no doctors in New York, Connecticut or Massachusetts. The closest doctors to New York are in Chicago IL (Richard Berger, MD, of Rush Presbyterian St. Luke's Medical Center in Chicago, who was the first doctor to perform the operation), Pittsburgh PA, and Paramus NJ. Concerning insurance coverage, there is a discrepancy between the web site (insurance covers the surgery) and Dr. Berger's voice mail (insurance may not cover the $11,000 surgery). Because it is experimental surgery, insurance may not pay for the procedure if you do not reside in the state where the procedure is performed because it is experimental surgery. In addition, currently the doctors are restricting the operation to candidates who are young, in good health and close to ideal weight.

Hip resurfacing

With hip resurfacing, a cup is inserted into the pelvis. The femur bone surface is smoothed out and then covered with an all-metal implant with a very short stem that is inserted into the femur bone. The very short stem preserves more of the femur bone than does a traditional hip replacement stem.

The FDA recently approved the BIRMINGHAM HIP™ Resurfacing System (BHR™). At this time, other companies are in clinical trials. The Birmington Hip Resurfacing web site allows you to search for doctors. I entered the zip code 10021 (for NYC) and found several doctors, including 2 at the Hospital for Special Surgery.

Advantages:

• Hip resurfacing is more beneficial for younger patients who want to be active.
• The stem of the hip resurfacing device that goes into the femur is much shorter than the stem of a traditional hip replacement, thus preserving more of the femur bone.
• The head of the device can be a 50-millimeter head, as compared to 36-millimeter or 28-millimeter head for a hip replacement. The advantage of a larger head is it is much harder to suffer a hip dislocation.
• A regular hip replacement may wear out sooner than hip resurfacing.
• When hip resurfacing does wear out, it is easier to then do a hip replacement, as opposed to doing a second hip replacement after a first hip replacement.

Disadvantages:

• It is more difficult to perform than a standard hip replacement.
• It is more costly than a regular hip replacement, at least currently.
• Because it is such a new approach, there are no long-term studies.
• There are few doctors trained in this procedure, but that should change over time.
• Certain insurance companies may not cover the procedure.

Note: I obtained the above information from multiple Web sites. Do a Web search for "hip resurfacing" to find sites with detailed information.

Questions and Answers

I suggest you do research beforehand and ask your doctor many questions. The following information came from Dr. Robert L. Buly in response to questions during the initial office visit.

What's removed in a hip replacement?

You keep all your muscles and tendons. The only part that comes out is the upper part of the femur. We clean the soft tissue out of the socket. A cup is placed into the pelvis. The stem goes into the femur. For anybody who is younger and has good bone, I go with an un-cemented replacement. The implants are made out of titanium, so it is pretty light. It has a rough surface on it, so we jam that in [so the bone can grow into the implant]. The way we do it, we ream-in your case it would be about a 52-, 54-millimeter implant. If it were a 52, and we would tell by the reamers, we would ream a 51 and put in a 52 [millimeter cup]. The bone has enough elasticity so that there is a nice tight fit. If need be, some of the cups have screw holes that are optional. If you put it in and then with the inserter go to move it, and if the whole pelvis is moving, you know that thing is really wedged in there and you don't need screws.

What is used to keep the replacement parts in place?

You can use cement. Cement was used for years. I use cement mostly in older people if the bone is not great. Anybody who has reasonable bone, I think it is much better to go with an uncemented implant. Ultimately, once bone grows onto this, it is very hard for this to ever loosen down the road [from the bone]. With uncemented replacements, they really don't loosen unless something makes them lose their bone, something chews away at the bone that is supporting the implant. The patient before you had a hip replacement done in 1985. She had a very thin polyethylene and a great big 32-millimeter head. It wore down the plastic. She is getting bone loss. The implants are still well fixed--both the stem and the cup. But she has lost a lot of bone because of the wear of the polyethylene.

How do you make the hip replacement last the longest?

The strategy right now on having a hip replacement last forever is to minimize the amount of debris that is generated at the articulated surface. That, right now, is the weak link in preventing a hip replacement from lasting forever. What's changed for you compared to the lady who had it done in 1985 is we have much better materials. As time goes on, we are learning more and more about the materials. Three flavors of surfaces: You can have polyethylene, you can have metal on metal [titanium with cobalt-and-chrome bearing surface], and you can have ceramic on ceramic. Those are the 3 choices.

What material choices are available?

1. Polyethylene

Polyethylene has been around since the early 1960's. The way it differs now is the way you process it makes a huge difference in how it wears. They used to radiate them in air. They found out when they did that it generated a lot of free radicals, and that lowered its wear resistance. What they do now is they radiate it in an inert atmosphere. The higher dosage of radiation increases the cross-linking in the polyethylene. If you take this polyethylene and do this 20 million times [moves it], that is about 20 years of use for somebody who is pretty active, and then you try to measure the wear. The wear is about 1/20th compared to the polyethylene we were using more than a couple of years ago. If you take the cup out after 20 million cycles and weigh it, you can't even measure the amount of wear. Sometimes you still see the machining marks after 20 million cycles, and that is with body weight load. So that is one way to go which is a very good option. That is what we use in most of our patients.

Bone grows into the stem, just as it does into the cup. This is the titanium stem, this is the rough coating, and that is where bone grows into that. You wedge it into the bone. The femur is hollow in the middle. The flutes [on the side of the stem] help to stabilize it for that 6-week period while bone is growing into it. In six weeks, if you try to take this thing out, you would have to chisel the bone off to get it out. So bone really adheres onto the surface.

One downside with this, and we don't know if this will be a problem yet or not. When you radiate it, the wear properties are much better, but the fracture toughness is lowered by about 40 percent. We don't know if that is going to make a difference. Nobody has fractured these yet that we know of. But engineers are a little worried that maybe that in 10 years they may crack or fracture. If that happens, it may be necessary to go in and change the insert. I recently revised some hips that have been in 18, 19 years... They were getting bone loss. We were able to just take out the polyethylene and put in one of the newer processed polyethylene, and that has worked out pretty well.

2. Ceramic-on-ceramic

Ceramic-on-ceramic is another option, where we have a ceramic head and a ceramic liner for the titanium cup. I do not have a ceramic inlay to show you because it is not FDA approved. Jack Nicklaus the golfer has one. The only way you can get ceramic-on-ceramic right now is through an FDA study. Patients who go into that study have to be randomized to get ceramic-on-ceramic or ceramic-on-polyethylene. The advantage of ceramic, just like the metal, you don't have the plastic particles that can be a problem. One downside of ceramic is there is a very low risk of fracture. It is estimated to be about 1 in 20,000. If you hit it hard enough or if you fall, you can crack either the head or the liner. If that happens, you have to re-operate.

3. Metal-on-metal

The other option is metal-on-metal [titanium with cobalt-and-chrome bearing surface]. Here you have a metal head with a metal inlay. You spin it; you feel very little friction. That's dry, so you can imagine the body when it's wet with joint fluid, it is even more slippery. It is a little heavier but you would not notice it. The advantage of this is you do not have the polyethylene. You look at this; it looks almost indestructible because it is entirely metal. The only difference is the bearing surface is cobalt-and-chrome instead of polyethylene. Titanium is great for bone ingrowth, but a poor bearing surface. Cobalt-and-chrome is super hard, and therefore a great bearing surface.

Now this cup that I use, (made by DePuy, a Johnson and Johnson company), will accept all 3 flavors. So you can have polyethylene put in and 10 years down the line it cracks. You can either put a new one in or put a metal-on-metal one or a ceramic-on-ceramic one in without having to take the cup out of the bone. You can just snap the new liner into it and be ready to go.

One downside of metal-on-metal, and the only reason I don't use it in everybody, is if you check blood levels of cobalt and chrome, which are the metals that are used for bearing surfaces, they are definitely higher than somebody who has a regular hip replacement. We're still talking about very low levels, like parts per billion, but they are definitely higher.

Metal-on-metal has been around a long time. It has been used in England and Switzerland going back to the 1960's. One design was very good. It generated almost no debris. If you re-operated on those patients, there was almost no metallic staining of the tissues. The implants look like they are just out of the box, 20 years later. The one made in England was not made very well and generated a lot of metal debris. You would re-operate and it would look like somebody poured motor oil in the joint. It was terrible. Some of them worked well because they had a lot of different manufacturers. Then polyethylene was getting more popular at that point, so almost everybody stopped metal-on-metal. Polyethylene was the workhorse for years and years.

But now we know that polyethylene can wear and can cause bone loss because the particles are irritating. So there has been a resurgence in metal-on-metal. The Swiss started using them again about 1988. In Europe they have a couple hundred thousand in. They looked at cancer rates. In Scandinavia everybody is in a large database because it is all socialized medicine. When they have done studies looking at cancer rates, they are actually lower in the group that has metal-on-metal compared to a regular hip replacement. The only one that was even close to being statistically different was leukemia was slightly higher. However, you are talking about a few cases. So if you change one or two cases, it makes a difference. Nobody linked it to any other problems. However, we don't know. There may be something that pops up 10 years down the road. So I tell people if they have any concerns about metal levels in the body, the ions that are generated are excreted in the urine. So as long as you have working kidneys, it doesn't seem like it builds up at all.

I wouldn't use it in someone who may be getting pregnant because we do not know we don't want to have anything that might hurt a fetus. However, if you wanted something that is the most durable or that you can pound on, that's probably this one. The other advantage is you can use a bigger head. You can use a 36-millimeter head compared to a 28-millimeter head] The advantage of a bigger head is it is much harder to dislocate. You would not feel the difference. Either one that is implanted will feel the same. However, with a 36 you can really go pretty far before the neck wants to impinge on the socket.

If you have concerns about metal levels, I would not use it. However, if you wanted the thing that is the most indestructible, the thing you can really beat on the most, I think this is the way to go. I have a guy I am doing tomorrow who is 22 [years old]. He is a skier and he wants to do flips. He wants one of these.

Now say something comes up 5 years down the road, and they say having elevated metal levels causes lupus or something. You could go in at that point and change it. You could take out the cobalt-and-chrome bearing surface and put in a ceramic or polyethylene. It is pretty simple. You would have to open up the hip joint, but it would be a lot less radical than taking the thing out of the bone. When the bone grows into these, they are hard to get out. We usually have to chisel them out. However, if you are just changing a liner, it is not a huge procedure.

What are the failure rates and re-operation rates?

The rates of failures are extremely low. I have yet to put one in as a primary that has failed. It works very well as long as you have good bone. Revisions are trickier. Revisions you have a lot of bone loss; it is a whole different kettle of fish.

The reasons you may need a re-operation down the road would be if it ever gets infected. The infection rates are pretty low from the surgery, about 2/10s of one percent, so about 2 out of a thousand. But if it ever got infected, we would treat it with antibiotics. If we couldn't get rid of it, we would have to maybe take the implants out and put a new hip back in.

The other would be if the implant ever malfunctioned. If it ever broke, if it ever got loose, that is called a revision. It means we go in and re-operate and fix what is broken. The risk of injuring nerves or blood vessels is very low. The sciatic nerve is in the back. The femoral vessels are in the front. We go in from the side, so the chance of nerve injury is extremely low. You can get blood clots in the legs. We put you either on Coumadin or aspirin after surgery to thin the blood.

What happens after the operation?

The thing that helps best is epidural anesthesia and getting you out of bed the day after surgery. I let patients go full-weight bearing with uncemented hip implants. It used to be we thought you had to be on crutches for 6 weeks because we do not want the implant moving around while the bone is trying to grow into it. These implants are so stable when we put them in, we let you go ahead and put full weight on it, and it doesn't make a difference. It makes your rehab a whole lot easier.

Even if you are feeling good, you need to have X-rays done every 2 years just to make sure nothing is malfunctioning. You would hate to go back in 10 years and see this huge hole in the pelvis from wear debris. There are a lot of problems that are easier to treat early on rather than waiting for a catastrophe.

We have you back [after the operation] in 6 weeks and 3 months. If things look good at that point, we see you back in a year. So we are talking about 3 visits after the surgery in the first year. If things look good that first year, we see you back every 2 years. [For the surgery] I can put in dissolving stitches, which I am starting to use more and more. That way you do not have to come back to have the [surgical] staples removed [since I live in Poughkeepsie, and Hospital for Special Surgery is in New York City]. We can use either staples or dissolving stitches. The dissolving stitches leave a very nice scar.

The day after surgery you are out of bed. The first day you don't do too much. You go from the bed to the door, maybe to the hallway. By the time you leave in 3 or 4 days, you can walk around the whole floor. You can go up and down stairs. You start with a walker the first 2 days. Sometimes we do someone on a Tuesday, by Friday they are ready to go home, they already are on a cane... Then you use a cane from 3 weeks to 6 weeks, depending on how quickly your muscle strength comes back.

You donate 2 units of blood... You need 1 week before surgery for your last donation. [Note: I donated my blood for my operation in East Fishkill, NY; the blood services sent it to HSS. You can donate 1 pint of blood a week. I donated twice, waiting 2 weeks between donations. Blood can be kept up to 42 days before it goes bad.]

We have a class that you go to [at HSS]. You meet the therapists. They give you a booklet of do's and don'ts. It is much better you come into the hospital with much better knowledge of what is expected.

What is "Minimally Invasive?"

Minimally invasive means you do the same operation, but it's like playing a game into how small we can make the incision and still do the operation... We make it as small as we need to. The thinner the patient, the smaller you can make it. With a male, it's harder to do that because you have more muscle. You need a certain size to be able to put the implants in without tearing muscle.

What are my limitations on physical activity?

You can do just about everything. Although we do not advise it, you can run, but there are so many ways to stay fit without running. You can skate, you can bike, you can swim, you can ski, and you can dance. I have patients who have implants who ski double blacks.

My Experience

Based on the information I received, I decided to go with minimally invasive surgery and metal-on-metal. The implants are titanium, and the bearing surfaces are cobalt-and-chrome. The following is a description of my progress immediately after the operation. Your progress may be different.

Wednesday November 13. The night before the surgery, I stayed at the elleaire Hotel, which is owned by Hospital for Special Surgery. The hotel is connected to the hospital by an overhead passageway.

Thursday November 14. Day of surgery. I had my right hip replaced. For anesthesia, I had an epidural block and a psoas block. I also had a sleeping medication drip so I would be sedated during the surgery. When they stopped the drip, I woke up. I did not have general anesthesia and thus did not have to worry about complications from general anesthesia. I started taking Coumadin (generic name is warfarin) to thin my blood to avoid blood clots.

Friday November 15. I had radiation therapy. My surgeon discovered that I have a condition where my muscles generate calcium deposits-bone spurs. I could have done nothing, taken medication for several months that also would also affect my bones, or do one-time radiation. I chose radiation. I had the procedure performed at New York Presbyterian Hospital, which is connected to the Hospital for Special Surgery by an overhead passageway. That day, I tried a walker for the first time. I walked 3 steps forward and 3 steps back. I felt dizzy, so that was the end of my first physical therapy.

Saturday November 16. They stopped my morphine drip, so I anticipated pain. However, the expected pain never came. Overall, I was very surprised by the lack of pain from the operation. I walked halfway down the hall with a walker, then returned to my room. I felt dizzy. Later that evening, I walked the entire hall with a walker without feeling dizzy.

Sunday November 17. I wanted to try a cane, but the physical therapist had not seen me before, so she had me use the walker again. The therapist did allow me to try stairs using a cane.

Monday November 18. I had 2 physical therapies. Both times I used a cane to walk the halls and to go up and down stairs. The doctor and I decided that I could check out. My spouse Lynne drove with our friend Bob Rother from Poughkeepsie to pick me up. I sat on 2 pillows so that my knees were lower than my hips to avoid dislocation of the hip.

Unfortunately, there was an accident on the Saw Mill River Parkway during rush hour. It took us almost 3 hours to get back to Poughkeepsie. Although we stopped so I could walk around a little, the long time in the car caused my hip to stiffen. I had lower back pain. Ironically, I had more pain from the lower back than I did from the surgery.

Wednesday November 20. Besides performing my assigned exercises, I walked outside for 15 minutes with a cane.

Thus, less than one week after surgery, I was mobile and pain free. I continued to do my exercises and walk, making sure I did not do anything stupid that might dislocate the hip. My next appointments with the surgeon were 6 weeks after surgery and then 3 months after surgery. I never used crutches. I was able to drive a car 6 weeks after surgery.

I hope this information is helpful for you or someone who might be considering a hip replacement. You may decide to choose a different procedure or type of material than I did, but hopefully the information will be of benefit to you.

Postscript

While traveling to Italy on vacation in June 2004, I set off the security metal detectors at each and every airport. The first time I went through the metal detector, I had my hand in my pocket holding a card from my doctor stating I had a hip replacement. When I set off the alarm, the security person said to me, "Sir, please take your hand out of your pocket." After that, I did not have my hand in my pocket when I went through security. Sometimes I was electronically wanded, and sometimes I was physically searched. My recommendation when traveling is that you should allow extra time at airport security checkpoints, for you will be searched every time, and sometimes the search will take a long time.

Update - November 30, 2004

I had my left hip replaced on November 30, 2004 by Dr. Robert Buly at the Hospital for Special Surgery. This time I requested the new HSS Fast-Track program. HSS started this program within the past 6 months; it had not been available at the time of my first surgery. The Fast-Track program allows a patient to be discharged from the hospital within 48 hours of surgery.

A person is eligible if he or she is under 60 years of age and in good physical condition. Since I was 52 years old and in good physical shape (except for my defective hip), I requested Fast-Track. HSS schedules a Fast-Track patient's surgery at the beginning of the day so that the patient has more time to recover and begin therapy that first day.

The patient receives less anesthesia than normal so that the patient is awake as soon as possible after surgery. For example, for my first surgery I woke up before 3 PM in the PACU, whereas for my second surgery I woke up before noon. Another difference deals with the epidural anesthesia used for pain mitigation. For a normal hip replacement, the epidural anesthesia line remains attached for 2 days. However, in the Fast-Track program, the epidural comes out the day after surgery.

In the post-anesthetic care unit (PACU) after surgery, the patient sits at the edge of the bed and attempts to stand up after the anesthesia wears off. In my case, I stood up for a short time with the help of a nurse and took one or two steps. However, I became dizzy and had to lie down again. That evening, in my hospital room, I used a walker to walk from my bed to the door and back, a distance of about 40 feet.

According to the HSS Fast-Track Progress Guidelines, on the first day after surgery the patient is to "progress walking using the walker with help from physical therapist or nursing staff. Walk at least 2-3 times." On the second day after surgery, the patient is to "progress walking using a cane, learn and practice how to go up and down stairs."

"You will be ready to go home, when you are able to...

• Walk independently,
• Get in and out of bed independently,
• Manage stair climbing using a cane, and
• Understand and follow all of the precautions."

On the morning of the first day after surgery, I walked the entire hospital ward using a walker. That afternoon I walked the entire ward using only a cane. I then went up and down stairs using a cane. Thus, on the first day after surgery, I had met the criteria for being discharged from the hospital. Dr. uly said he has had a few patients that he discharged after 24 hours, although most are discharged after 48 hours. However, I then had a setback when my left adductor muscle spasmed. I always had problems with my adductor muscle because of my hip problem, and apparently my adductor had been on the edge of being traumatized. Because of the muscle problem, I ended up leaving the hospital on the 3rd day after surgery. However, if it had not been for the muscle, I would have been released earlier.

Although the Fast-Track program is not for everyone, it is a great option for those young enough and in good shape. I highly recommend the program.

P.S. One difference between my first home recovery and my second home recovery was that I used Coumadin (Warfarin) as a blood thinner after my first surgery to prevent blood clots. I had to have my blood analyzed weekly, and I had to have my dosage of Coumadin adjusted based on the blood results. After my second surgery, I used aspirin twice a day as a blood thinner, and I did not have my blood analyzed. This change probably has nothing to do with the Fast-Track program, but I mention it because I much preferred aspirin to Coumadin.