Point-Counterpoint: Anterior vs. Posterior Hip Replacement

Surgeons sound off on the best way to tackle THA cases.

Outpatient Surgery Magazine spoke with two pairs of surgeons to debate the most effective technique for performing total hip arthroplasty (THA). Is the anterior approach — where the incision is made at the front of the hip — or the common and traditional posterior approach — where the incision is made in the side of the hip, along the outer buttock area — the safest, most cost-effective way to achieve optimal outcomes on same-day THA patients?

POINT: The anterior approach enables speedier recoveries, more accurate implant placement and reduced dislocation rates.

Ilda Molloy, MD, MS
Primary hip and knee replacement specialist and assistant professor of orthopaedics at Yale School of Medicine in New Haven, Conn.
One of the prime benefits of the anterior approach is the fact that it affords patients a quicker, smoother recovery. When I’m highlighting the pros of this technique, I always tell patients they’ll be able to get back to their day-to-day lives sooner with the anterior approach. A significant amount of the data shows that patients can return to physical activity and their daily activities — especially in those critical first weeks after discharge — more quickly and easily from the anterior approach compared to the posterior one. I also believe the anterior approach makes it easier for me to maintain control in terms of the leg lengths of the patient. One of the most common conversations we have in terms of the risks and benefits of hip replacement centers around leg inequality — whether one leg is longer or shorter than the other. With the anterior approach, the patient is supine, and you can see directly what their leg lengths are. When patients are positioned differently — say, on their side — it’s more difficult because their ankles don’t always line up, and you’re using a little more extrapolation.

Finally, in my opinion, the anterior approach makes it easier for me to gain direct visualization of the implants. I print out the X-ray, and I see where I expect my implant to be. Anatomically, it makes more sense to me as a surgeon to be looking directly at it. If I can put the implant in a better position, then the patient will also have a better result. This is supported by the fact that the dislocation rates with an anterior approach are lower than with a posterior approach.

Lee Rubin, MD
Hip and knee replacement specialist and assistant professor of orthopaedics at Yale School of Medicine in New Haven, Conn.
The anterior approach has been the main driver of outpatient hip arthroplasty in the U.S., and I think a major reason why surgeons are using the anterior approach is because it really works well in the ASC setting. I perform all my cases using the anterior approach except for a small number of primary revisions, fractures and partial hips. The approach allows surgeons to put implants in more reliably and more accurately get leg length, offset correction and dial in what we want to do.

Many surgeons will add fluoroscopy, which is very easy to use when the patient is flat in a supine position, and some surgeons will use navigation or superimposed fluoroscopic guidance. Again, with the anterior approach it’s all very easy to do. The bottom line is all the studies show that the cup is more accurately and reliably placed in the right plane of abduction and anteversion at a very high rate — in the high 90s — with the anterior approach. Plus, as Dr. Molloy points out, the dislocation rates are going to be lower because you’re dialing in the correct parameters for reconstruction more reliably. Finally, according to the data that’s come out from Mayo Clinic, surgeons have shown in a large series of patients they operated on over the last five years that the dislocation rate is five times lower with the anterior approach versus the posterior approach — using the same instruments, the same implant companies and so on. Data out of NYU also showed us that the anterior approach had a lower rate of “failure-to-launch,” which is a planned outpatient procedure where patients failed to go home. That rate was significantly higher in the posterior group and much lower in the anterior group. Ultimately, patients go home more easily, they have less pain, they’re easily walking, and they have fewer narcotic demands overall — especially with the nerve blocks that we’ve been using. There’s so much data that has emerged in the last five to 10 years making a fairly compelling case that the anterior approach leads to better patient outcomes.

COUNTERPOINT: It’s easier to get out of trouble from the posterior approach, a technique that allows surgeons to avoid cutting into the abductor muscles and manage complications more easily.

P. Maxwell Courtney, MD
Division chief of adult reconstruction and associate professor of orthopaedic surgery at Rothman Orthopaidic Institute in Philadelphia
I have great success in sending my posterior hips home on the same day from the surgery center, recovering just as quickly as patients undergoing an anterior approach. I think the biggest advantage of the posterior approach is you don’t need to touch the abductor muscles, the big muscle group around the hip. It’s also an extensile approach. If you get into trouble, or you’re performing more complex cases, you can extend the incision and you can fix anything through the posterior approach. I have never seen a hip replacement that needed to be done through an anterior approach. There are, however, plenty of complex hip replacements and revisions that require a posterior approach. I also think some patients see the posterior approach as more cosmetically appealing because the incision is on the side of your hip as opposed to in the groin. I don’t think that matters, though. I also think you can, depending on the surgeon, do the posterior approach through a smaller incision, but I’ll be the first to tell you that the incision size has nothing to do with the patient’s outcome.

Nicholas Bedard, MD
Assistant professor of orthopedic surgery at Mayo Clinic in Rochester, Minn.
I do the posterior approach almost exclusively for hip replacement cases — probably 99% of my first-time hip replacements are done from this approach. In terms of the big picture, the data is clear that the overall complication risk is very similar across approaches. It is more a matter of how the pie chart of complications breaks down.

Certain parts of the total hip replacement procedure are more difficult when performed from an anterior approach, and other parts can be more difficult to perform from a posterior approach. As a result, each approach lends itself to a different complication profile. The major complications we worry about for total hip replacement are dislocation, infection, implant loosening or fracture. The posterior approach has a slightly higher rate of dislocation, but that must be contrasted with a higher rate of femoral-related complications — like a femur fracture or implant loosening — with the anterior approach. Some data also suggests the anterior approach might have a higher rate of wound complications, and possibly infection, by the nature of the incision being closer to the groin and slightly longer operative times.

I’m happy with my low dislocation rate from a posterior approach. I can minimize the risk of other complications associated with the anterior approach and still get my patients home the same day. Additionally, as a surgeon who performs a lot of revision surgery, I do think that when a complication does occur, I can often manage it with less surgery if the patient previously had a posterior approach compared to patients who have complications from an anterior approach. If you have complications from the front, the revision often requires a separate incision, a bigger revision surgery and it can have a magnified impact on a patient.

Crucial caveat to the debate

While each surgeon we spoke with clearly felt very strongly about their preferred protocol for total hips, they were all quick to point out the procedure was generally an extraordinarily successful surgery from any approach with the right surgeon at the helm.

“Hip replacements are so successful overall that we’re comparing rates of a given complication of 1% versus 1.5%,” says Dr. Bedard in reference to the approach. “The procedure is very successful, regardless of how you how you do it.” In fact, the surgeons we spoke with all pointed out that there’s a major marketing component to the anterior-posterior debate, with surgical techniques that have been around forever being portrayed as cutting edge.

For patients, Dr. Molloy argues, the question isn’t about anterior or posterior as much as about the trust and comfort with the surgeon to whom they entrust their care. “What I would say to a patient is that you want a surgeon who is comfortable and skilled at what they do,” she says. “You don’t want to go to a person who is a strictly posterior surgeon and be like, ‘I need an anterior approach.’ You want them to do what they’re best at. If that’s not what you’re looking for, based on your research as a patient, then you find somebody else. Because let me tell you, there are a lot of anterior surgeons who also don’t do a great job and vice versa.”

What I would say to a patient is that you want a surgeon who is comfortable and skilled at what they do.
Ilda Molloy, MD, MS

This type of logic should make sense to patients, and perhaps Dr. Courtney puts it best by comparing the approach of a surgeon to the course-plotting of a pilot. “When you have a patient say, ‘I want my hip done anteriorly,’ I’m more than happy to refer them to my partners,” says Dr. Courtney. “If you’re flying from New York to LA, would you tell your pilot, ‘I want you to take a northerly route over Chicago, then over Wyoming, and then fly your descent southward into LA.’ You would never do that because your pilot is going to take you in the approach with which they’re most comfortable and most familiar — the approach that’s going to give you the best outcome in their particular hands.” OSM