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Total Hip Replacement 101 Updated 2016 

by Bob Kopac

This is an update to a total hip-replacement (THR) article I wrote many years ago called “Total Hip Replacement 101” that exists on the Mid-Hudson Road Runners Club (MHRRC) website. Unfortunately, due to technical issues, that article containing now-outdated information cannot be modified or removed from the Internet. The purpose of this article called “Total Hip Replacement 101 Updated 2016” is to replace that article with updated information. Please ignore all information in the original article.

In 2015 I had to have 2 hip revision surgeries to replace my original MoM hip devices. Almost all the surgeons at Hospital for Special Surgery (HSS) in New York City no longer use MoM for hip replacements and revisions. Based on personal experience, I no longer recommend metal-on-metal (MoM) hip devices. 

Reason for my MoM THR

I originally had both my hips replaced due to a genetic birth defect called acetabular dysplasia, where my hip sockets did not form completely before birth. I had my first hip replacement in 2002 and my second in 2004.

Every few years after my surgeries, I would see my surgeon Dr. Robert Buly at HSS for a routine checkup, including X-rays and a blood test to check the metal levels in my blood. After a decade, suddenly my cobalt and chromium counts skyrocketed into dangerous numbers. My cobalt level went from 2.9 to 12.8 parts per billion; above 7.0 is reason for concern. 

Dr. Buly then ordered MRIs to determine if flesh necrosis (death of tissue) or bone deterioration had occurred. The MRIs showed there was no flesh necrosis and no bone deterioration. However, the MRIs did reveal metal-induced synovitis and quite a bit of fluid tracking up into the psoas bursa on both sides; that is, I had large cysts on either side of my body filled with "sludge", which was my body's attempt to fight the metal levels. Because of this, I needed hip revision surgery to replace my MoM and to get rid of the synovitis. Note that the titanium femur rods or well-fixed acetabular shells did not have to be replaced, only the acetabular liners and femoral heads.

During all this time, I was asymptomatic; that is, I did not experience any pain or outward symptoms. Only the routine blood tests uncovered the problem.

Dr. Buly performed the left hip revision in May 2015 and the right hip revision in November 2015. He replaced the following cobalt-and-chromium parts: the femoral head (ball) with ceramic and the cup liner with highly cross-linked polyethylene. After the revision, there are no more cobalt-chrome parts in my hips.

My MoM THR system had been Johnson & Johnson Depuy with an S-ROM stem, an Ultamet metal-on-metal bearing with a 36 mm head and a Pinnacle cup. This type of system has not been recalled as of yet. I gave permission for my devices to be examined as part of a study to determine if my THR system should be recalled.

Note that in August 2010 Johnson & Johnson recalled the Depuy ASR XL Acetabular MoM THR system due to a large number of failures in patients. The design flaw was a truncated hemisphere encompassing 160° instead of the standard 180°. This was done to minimize impingement and improve range of motion. However, unfortunately the design created increased edge loading and metal particle generation. In November 2013 Johnson & Johnson agreed to pay $2.5 billion to resolve thousands of defective Depuy ASR hip implant lawsuits.

Hip replacement options

The following information is from Dr. Buly in response to questions during my initial office visit, along with updates from Dr. Buly based on new information.

Traditional

Traditional hip replacement involves a 8-12 inch cut of the thigh and may involve cutting through muscles. Time of surgery is 1.5 hours.

Advantages: 

Disadvantages: 

Minimally invasive surgery (MIS)

Many doctors have performed this procedure for several years using traditional medical instruments, and MIS is becoming standard practice. 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 for all my operations.]

Advantages:

Disadvantages: 

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 cemented into the femur bone. The very short stem preserves more of the femur bone than does a traditional hip replacement stem.

Advantages:

Disadvantages:

Do a Web search for "hip resurfacing" to find sites with detailed information and possible side effects.

Material choices

Dr. Buly provided the following information over various consultations.

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 for sterilization. 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, is that 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. Jack Nicklaus the golfer has one. The advantage of ceramic, just like the metal, you don't have the wear-related plastic particles that can be a problem. One downside of ceramic is there is a very small 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.

[Since the time I wrote the original article, more information has surfaced regarding possible problems with ceramic-on-ceramic hip replacements. Some patients have had audible squeaking of the devices, causing these patients to have revision surgery to replace the ceramic-on-ceramic devices. Severe squeaking of sudden onset may indicate a fracture of a ceramic liner. For more information, do an Internet search for "ceramic hip squeaking" to read dozens of articles about the potential problems.]

3. Metal-on-metal (MoM)

The other option is MoM (ca cobalt-and-chromium bearing surface). Although doctors at other hospitals still use MoM, almost all doctors at HSS no longer use MoM.

[Since my original THRs in 2002 and 2004], this option has fallen out of favor at HSS due to metal particles causing inflammation, soft tissue damage and bone loss in the hip. FYI, metal levels in the blood do not seem to be a problem, as these ions are excreted by the kidneys. It is the metal deposition in the soft tissues and bone around the hip joint that causes the damage.

If you have had an MoM hip replacement, you periodically should have a blood test to check the metal counts in your blood. If you need to replace an MoM device, you could take out the cobalt-and-chromium bearing surface and put in a ceramic or polyethylene. It is pretty simple as long as there is minimal bone loss and the implants have not loosened. You would have to open up the hip joint, but it would be a lot less radical than taking well-fixed implants 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.

Questions and Answers

What's removed in a primary THR?

You keep all your muscles and tendons. The only part that comes out is the upper part of the femur (the femoral head). 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 uncemented implants are made out of titanium, which are pretty light. These porous-coated implants have a rough surface coating, which helps to provide immediate press-fit stability and eventual bone ingrowth after several weeks. The implants may be cemented in place with methylmethacrylate if the bone is not sufficiently strong to support uncemented implants. Cemented femoral stems are made of cobalt-chrome, cemented acetabular cups are made of polyethylene. 

The way we do it, we ream; in your case the cup 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] to wedge the cup in. 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 after seating the cup, wiggling the inserter handle causes the whole pelvis to move, you know that the cup 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 as long as possible?

The strategy right now on having a hip replacement last forever is to minimize the amount of debris that is generated at the articulation 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. 

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 on aspirin after surgery to thin the blood. Patients who have an increased risk of deep vein thrombosis or pulmonary embolus may require a more potent anticoagulation drug.

What happens after the operation?

The thing that helps best is epidural anesthesia and getting patients out of bed as quickly as possible, hopefully even the day of surgery. While keeping the epidural catheter in place for 24 hours provides excellent pain control, it may slow down the rehabilitation. Increasingly, we are starting to remove the epidural. 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 now 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 3 years or so 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 if need be, 3 months. If things look good at that point, we see you back in a year. So we are talking about 2-3 visits after the surgery in the first year. If things look good that first year, we see you back every 3 years. [For the surgery] I can put in dissolving stitches, which I use in nearly every case. The wound is closed with Dermabond, similar to Crazy Glue; showering can start immediately. That way you do not have to come back to have the [surgical] staples removed [since I live in Poughkeepsie, and HSS is in New York City]. The dissolving stitches leave a very nice scar.

The same day, or at the latest, 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 1-2 days, you can walk around the whole floor. You can go up and down stairs. You start with a walker the on the first attempt and quickly transition to a cane. Discharge comes after physical therapy goals are met. You use a cane from 1 to 4 weeks, depending on how quickly your muscle strength comes back.

We no longer require autologous blood donation for primary hip replacement. With less invasive incisions, hypotensive anesthesia and the use of tranexamic acid (which decreases surgical incision blood loss), patients rarely need a blood transfusion.

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

What is "Minimally Invasive” Surgery?

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 Hip Replacement history

Based on the information I received, I decided in 2002 to go with minimally invasive surgery and MoM THR. As explained above, this later turned out to have been a mistake due to cobalt and chromium metal fragments a decade later entering my blood stream from metal wear debris, causing synovitis in my case. Again, it is the local deposition of microscopic metal particles in the soft tissues around the hip that causes the damage, not the metal ions in the blood stream. The fact that metal ions get liberated into the bloodstream makes it convenient to monitor how much is actually generated by the hip articulation. The ions that find their way into the bloodstream are passed out of the body in the urine.

November 14, 2002 is the day I first went bionic. I had a THR of my right hip performed by Dr. Robert Buly at HSS. I had a genetic birth defect of both hips called “acetabular dysplasia”, which means my hip sockets were partially formed and shallow. This condition led to severe osteoarthritis.

The following is a description of my progress immediately after my first hip replacement operation. Your progress may be different.

Wednesday November 13, 2002: The night before the surgery, I stayed at the Belaire Guest Facility, which is owned by Hospital for Special Surgery. The facility 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 called hetero-topic ossification or hetero-topic bone. I could have done nothing, taken a non-steroidal anti-inflammatory medication such as Indocin or Naprosyn 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, and 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. For the drive home, I sat on 2 pillows so that my knees were lower than my hips to avoid dislocation of the hip. The long time in the car caused my hip muscles to stiffen, and I had lower back pain. Ironically, I had more pain from the lower back than I did from the surgery. I recommend stopping every half hour and taking a walk break.

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.

Second Hip Replacement

In November 2004, I had my left hip replaced by Dr. Buly at HSS. This time I requested the HSS Fast-Track program, which 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. 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 day.

The patient receives less anesthesia than normal so that the patient is awake as soon as possible after surgery. 

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.

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 my second 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. Buly 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.

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.

Hip Revisions

I had my 1st hip revision in May 2015 and my 2nd hip revision in November 2015. For the 1st revision, I had a very late afternoon surgery and thus was in the hospital for 2 nights. However, the day after surgery I was completely pain free and was able to negotiate the hallways and steps with a cane, and I was home by mid-afternoon 2 days after the surgery. For the 2nd revision, I had an early morning surgery. That afternoon I walked in PACU, first using a walker and then a cane. The next morning, using a cane, I walked the hospital ward floor and walked up and down steps. I left the hospital at 4:00 PM that day, so I was in the hospital for only one night. Since I had been pain-free before the revisions, I had exercised in anticipation of the surgeries, and that training paid off for me.

Traveling with a hip replacement

While traveling, I always set off the security metal detectors at airports. My recommendation 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. Often this is done in an isolated area, and you will not be near your carry-on luggage or any laptop you may be carrying.

Conclusion

I hope this information is helpful for you or someone who might be considering a hip replacement. If you need a hip replacement, do your research, gather as much information as you can, and discuss the various options with your surgeon.