Hip resurfacing offers bone-saving alternative to total hip replacement

Scripted by Michaela Meaney, animated by Next Media Animation. 

By Michaela Meaney 

At 53 years old, arthritis controlled Timothy Byrne’s life. The pain in his hip affected just about everything he did. He could not sleep. He had trouble getting in and out of the car. Even bending over to start the lawn mower felt like a challenge.

“I really couldn’t pull the pull cord on the lawn mower anymore because of the pain factor,” said Byrne, of Wickliffe, Ohio, now 57 years old. “And, you know, if it takes three of four pulls to get the lawn mower started, I could hardly pull it once without being in excruciating pain, much less walking to mow it once it started.”

Byrne’s job as a butcher also required him to be on his feet nearly 45 hours a week, walking, standing and constantly moving around. So in 2010 Byrne decided the pain was too much to bear. He scheduled what is called a Birmingham hip resurfacing, an alternative procedure to a traditional total hip replacement.

Byrne has since returned to his active lifestyle and said he does not experience any problems with his hip. But the procedure does have its drawbacks and not every patient has a success story like Byrne’s. For older, less active patients and smaller patients, they face an increased risk of a type of fracture that would not occur in a total hip replacement.

WHAT IS A BHR?

A hip resurfacing differs from a total hip replacement in one major way: much of the bone is spared.

The femoral head, or the rounded part of the femur covered in cartilage, is connected to the pelvis by the acetabulum, or the hip socket. In a total hip replacement (THR), the femoral head and neck are removed and a metal implant replacing that part of the bone is inserted into the bone marrow cavity. A metal cup is also placed inside the hip socket, and since the implant’s head is smaller in size than the body’s original femoral head, a liner is also placed inside the cup. In most cases the liner is plastic and the implant’s head is metal, but heads and liners can also be made of ceramic.

In a hip resurfacing, the femoral head and neck are not removed but rather reshaped. The head is essentially smoothed down as areas where it lacked cartilage are cut off and a new surface is created. A mushroom-shaped implant is then cemented over what remains of the patient’s femoral head. In this procedure a cup is also placed into the hip socket, but no liner is inserted since the femoral head remains closer in size to that of the body’s original bone.

“It’s literally like putting on a hat instead of cutting off your head,” said Dr. Peter Brooks, orthopedic surgeon at the Cleveland Clinic.

Brooks (r, back) and his team perform a Birmingham hip resurfacing at the Cleveland Clinic's Euclid Hospital.
Dr. Peter Brooks (r, back) and his team perform a Birmingham hip resurfacing, an alternative to a total hip replacement, at the Cleveland Clinic’s Euclid Hospital.

In addition to hip resurfacing, Brooks also specializes in total hip and knee replacements. Since the FDA approved the procedure in 2006, Brooks has performed over 2,200 Birmingham hip resurfacing procedures (BHR) – more than 300 per year – with a failure rate of less than 0.5 percent.

“Most surgeons don’t do resurfacing,” Brooks said, who is also a consultant for Smith & Nephew, the company that manufactures the BHR device. “Perhaps 1 percent of orthopedic surgeons will even do resurfacing devices, so just statistically you’re very unlikely to meet a surgeon that does resurfacing.” For surgeons to perform the procedure, the FDA requires they go through a special training.

The Birmingham hip resurfacing was developed in Birmingham, England, in the late 1990s by British orthopedic surgeon, Derek McMinn, the surgeon who trained Brooks.

When it comes to hip resurfacing, “Birmingham” is more like a brand name for the device’s design and technique, as there are other resurfacing devices available and ones in the past that were taken off the market. In fact just this year two devices available in the U.S. were taken off the market, Brooks said. According to the 2013 annual report released by the Australian Orthopaedic Association National Joint Replacement Registry, BHR was the most used device with the one of the lowest failure rates in procedures reported to the registry.

A PROCEDURE FOR YOUNGER PATIENTS

Byrne was only 53 when he received his BHR, as is the case with most patients who have the procedure.

“I understood there were greater limitations placed on you after a complete hip replacement as compared with a Birmingham,” said Byrne. “And that’s why I went with the Birmingham, because it was considered, they said, ‘a young person’s hip replacement,’ because after the Birmingham you could get back to doing whatever you wanted to with fewer limitations than a hip replacement.”

But the BHR is not for everyone. Brooks screens patients and normally only selects younger, active patients with large, strong bones. If it is done in an older patient, “you’ve lost two of the most common advantages of hip resurfacing – the increased activity levels and the ability to avoid a revision total hip replacement,” he said.

ACTIVITY LEVELS

One of the reasons why a patient would be able to get back to an active lifestyle with a BHR is because of the device’s design. The average size of a femoral head in a hip resurfacing patient is 52 millimeters, according to Brooks. But in a THR the femoral head and neck are cut off and replaced by an implant. If a patient receives an implant with a head that is 32 millimeters, a liner must compensate the rest of that space, and this opens up the opportunity for the device to pop out of the socket.

With a younger patient the likelihood of an implant popping out of the socket may be greater than with an older patient, since younger patients are usually more active than older patients. And according to Brooks, the most common reason for repeated hip surgery in the U.S. is the device popping out. In more than 2,200 BHR procedures performed by Brooks, not a single device has popped out of a patient’s hip socket.

As younger patients also tend to be more active, they may still continue to do things that would affect their hip implant, such as playing high impact sports. For Dr. Riyaz Jinnah, orthopedic surgeon at Southeastern Health, this is something he would discourage his THR patients from doing.

“What you’re worried about more is the loosening of the component from the bone,” said Jinnah, who has been doing hip resurfacing since the 1980s and Birmingham hip resurfacing since being trained by McMinn in 2006. Since the 80s Jinnah has done over 1,500 hip resurfacing procedures.

Brooks agreed that impact sports are not recommended for THR patients. With resurfacing patients, it’s a different story.

A Birmingham hip resurfacing device, made from a composite of cobalt and chrome, is a small implant used in an alternative procedure to total hip replacement. Michaela Meaney/MEDILL
A Birmingham hip resurfacing device, made from a composite of cobalt and chrome, is a small implant used in the alternative procedure to total hip replacement. Michaela Meaney/MEDILL

“There’s actually a tiny gap in between the ball and the socket, and it’s designed to pull fluid in with movement,” Brooks said. “So your resurfacing device actually does better and lasts longer if you’re active.”

Texas Rangers pitcher Colby Lewis had a hip resurfacing in 2013 and has since returned to playing major league baseball. The only professional athlete who returned to the field with a THR was Bo Jackson, after being injured during a football game in 1991. However he returned to the MLB and not the NFL.

“The big advantage of that type of hip replacement is the recovery of your range of motion, for people like ballerinas, dancers, or people that don’t want their hip to come out of the socket,” said Dr. William Long, orthopedic surgeon at Good Samaritan Hospital in Los Angeles. “If they’re going to put themselves at risk of that, that hip does better than other hips in that area.” Long is also the medical director of Good Samaritan’s Orthopaedic Computer Surgery Institute.

AVOIDING A REVISION SURGERY

The plastic liner in the THR also presents an issue. It wears.

“Many times I go into surgery just to change a plastic, like you would change your breaks,” Brooks said. “Maybe pads this time, another time you might need something more, eventually you just get a new car.”

Brooks also said a ceramic liner may crack.

A Birmingham hip resurfacing device compared to two total hip replacement devices (l to r).
A Birmingham hip resurfacing device compared to two total hip replacement devices (l to r). Michaela Meaney/MEDILL

The THR changes the way weight is distributed throughout the femur, which can have adverse effects on the upper part of the bone. According to Brooks, when the top of the femur is cut off and the implant is placed down the bone marrow cavity, a patient’s body weight is transferred to the end of the implant.

“As a result the remaining bone of the upper femur is not loaded. So it gets weak,” Brooks said. “So you lose bone on the day of surgery, you lose bone through weakening over the next four of five years as the body adapts, and in fact, you gain thicker bone farther down in your leg where the stresses are now being transferred.”

Because the bone has become weak, there is potential for a fracture.

So why would a BHR not be viable for older patients?  A THR works better for them because they generally have a shorter life expectancy.

“The main advantage of resurfacing in younger people is that it gives them another step before they need a revision of a total hip replacement,” Brooks said.

Jinnah explained that in a 60-year-old patient a THR would last on average 15 to 20 years.

“But if you’re 40 and you’re doing a total hip, then you’re going to have to have a revision and then another revision, so really resurfacing started as looking for something less radical as a total hip so that we could, they way that I put it is, add one more bite at the cherry,” Jinnah said.

NOT FOR EVERYONE

Often times the BHR is marketed as a less invasive procedure, since more of the bone is saved when compared to a THR. However Brooks explained otherwise:

“It’s actually more invasive because these parts are bigger, chunkier parts, you need a somewhat longer incision to get them in, and the dissection – the separation of your muscles and ligaments – is more extensive with a resurfacing. So it is actually a bigger operation than hip replacement,” he said.

And as with any other surgical procedure, the risks of infection and blood clots are also present.

However with the BHR there are two main risks unique to the procedure. The first is too much metal debris in the body.

The BHR device is a composite of cobalt and chrome. Chromium naturally occurs in all humans but it occurs at very low levels. The amount raises with a BHR, but not by that much.

“Right now, un-operated, we have less than a half a part per billion of chromium circulating in our bodies,” Brooks said. “After a properly done Birmingham, you can expect that level to roughly triple to about one and a half parts per billion.”

Brooks explained that too much metal debris could cause pain, swelling, tissue destruction and damage parts of the body like the heart. Metal debris could get into the body through one of three possibilities:

  • The device implanted was not a Birmingham. Brooks noted that some devices spread excess metal debris more than others.
  • The procedure was not done correctly. If the device’s cup is inserted into the socket at an incorrect angle, the head will rest on the rim, or the edge of the socket. Then the entire day the head’s rounded surface will scrape against the flat edge and metal shavings will make their way into the body, said Brooks.
  • The patient is too small. This means patients with smaller bones, usually women, have less of a success rate than those with larger bones. A 2012 study published in The Lancet on behalf of the National Joint Registry for England and Wales looked at hip resurfacings in 31,932 patients. In women, those with smaller resurfaced heads had higher failure rates. With the BHR, Smith & Nephew’s smallest sizes begin at 38 millimeters, but Brooks will not resurface any women that fall under the first three sizes. Brooks also explained that hip dysplasia, which affects more women and causes the femoral head to twist out of the socket, can adversely affect a hip resurfacing as well.

The other risk unique to a hip resurfacing is a femoral neck fracture. Because the femoral head and neck are not removed in a resurfacing when they would be in a THR, the neck is weaker while in recovery from being grinded down during the procedure.

“That femoral neck piece, that piece of bone it could break,” said Long. “And a total hip will never break at the neck, almost never.”

To limit the possibility of that happening, Brooks advises his patients not to do any activity that could put too much pressure on the weak bone for the first year. Jinnah also recommends his patients to do the same, but only during six months of recovery.

“And I tell people it’s like ice cream falling out of your ice cream cone,” Brooks said. “Everybody cries and you have to get another one. Unfortunately the other one with a resurfacing will be a total hip replacement, and that will disappoint you.”

Long, who specializes in revision joint replacement surgery, said he believes it is too much of a risk to leave the femoral neck attached.

“Well if they put a stem in there the patient could be active immediately, and they wouldn’t have to have any year period to hope the bone gets stronger to prevent it from breaking,” Long said. “Why have a fat neck that breaks when you can have a metal neck that will never break?”

Long also explained that even if the neck does not break from being too weak, it does have the possibility of breaking if the resurfacing is not done correctly.

“If you don’t have everything perfect, the neck can hit the cup, and the neck breaks because of that,” he said. Long does not perform hip resurfacing, but he did spend a week in Vietnam learning informally from McMinn.

WHAT IT COMES DOWN TO

Like any surgical procedure, there are benefits and risks to doing a resurfacing. For Brooks it is about picking the right patient, the right device and the right surgeon.

Both Brooks and Jinnah stressed the importance of picking a surgeon who has done a large volume, as it takes more time to learn the complicated procedure.

“I’m doing more than 300 a year, and at that I’m still learning and I’ve been doing it for eight years,” Brooks said.

But Jinnah said that doctors should not deny the patient of the procedure if the patient is a viable candidate.

“If you don’t do them don’t do them, but send them to people who do,” Jinnah said. “Don’t deprive the patient of that thing.”

However most surgeons are more likely to recommend a procedure they do and think is best.

Long, who does over 100 revision joint replacements each year, does believe that the BHR is a good procedure.

“I’m not saying one is bad and one is good, or one is great and one is mediocre, I’m saying that I believe that what I do is better,” he said.

Brooks said, “Really the only way if you’re a patient to know if you’re a candidate for a resurfacing is to speak with someone who does it.”