Rodriguez v. Springer: The Anterior Approach: Better, Faster, Safer
OTW Staff • Fri, January 5th, 2018
This week’s Orthopaedic Crossfire® debate was part of the Annual Current Concepts in Joint Replacement® (CCJR), Winter meeting, which took place in Orlando. This week’s topic is “The Anterior Approach: Better, Faster, Safer.” For is Jose A. Rodriguez, M.D., Hospital for Special Surgery, New York, New York. Opposing is Bryan D. Springer, M.D., OrthoCarolina Hip & Knee Center, Charlotte, North Carolina. Moderating is Thomas S. Thornhill, M.D., Harvard Medical School, Boston, Massachusetts.
Dr. Rodriguez: So better, faster, safer…in my hands. I don’t know about you guys, but my decision making is limbic. How we perceive data is how we feel, but how we feel influences how we perceive the data.
I have presented this data from this podium previously on comparing anterior and posterior approaches by two very good surgeons (Clin Orthop Relat Res, 2014), using the objective measures of the Timed-up and Go (TUG) test, Functional Independence Measures, as well as a milestone diary.
We found that in the hospital there was a significant improvement in total score in the Functional Independence Measures and the time to achieve that peak score with the anterior approach. The TUG test was better with the anterior approach.
There was no difference in this study in the length of stay.
By two weeks, most of those measures had normalized. The TUG test remained significantly better for the anterior approach and by six weeks everything was basically the same.
More recently a much better study was presented by the folks at Mayo Clinic (Taunton et al., AAHKS 2016); 100 patients came to all surgeons; they were then randomized to go to either an anterior surgeon or a posterior surgeon, with similar in-hospital assessments.
In all the assessments that were made—discontinued walker, discontinued gait aids, opioids, stairs and walking six blocks, there was a marked improvement in the anterior group. They concluded, obviously in a familiar way, that both approaches provided excellent recovery. The anterior approach was faster at two weeks. How that matters? That’s up to you.
What about gait? We looked at gait analysis in two cohorts pre-operatively and at six months (J Arthroplasty, 2014). Of all the variables that we measured, the only difference that we found was in the range of motion during the gait cycle.
Both groups significantly improved in the frontal and sagittal planes, but there was no improvement with the posterior approach in the transverse plane. That is the amount of internal and external rotation that occurs during gait. This is not surprising given the dislocation precautions we had imposed on these people.
What about muscle strength? We measured muscle strength in the two cohorts using a technique that’s well published (Thorborg et al., Scan J Sci Sports, 2010). And we found that between pre-op and six weeks, the posterior group had a significant external rotation weakness and the anterior group had a notable flexion weakness. By three months, the flexion weakness had resolved in the anterior group. The external rotation weakness had improved with the posterior group, but there were still some clear measurable changes.
Precision. Looking at acetabular component anteversion for my anterior group patients -- as I critically analyze my X-rays-- I got better. I only had two dislocations within the first 100 cases. We then measured muscle volumes.
What we found was that there was relative comparability between the two cohorts in terms of anterior and posterior muscle volumes. For the anterior group, all the muscle volumes improved except for the obturator internus which we routinely release during the procedure. With the posterior approach, in addition to the obturator internus, there was also the obturator externus, piriformis and quadratus, a drop which is sustained post-operatively in the muscle volumes. All other volumes improved.
The question is whether you should use it and I would give you maybe not because there is no free lunch. Everything has downsides.
What are the downsides? First is wound healing. In the cases that we’ve published we’ve documented a 1.9% reoperation rate mostly due to the BMI [body mass index]. There is a dose response curve to their BMI and diabetes has a very significant effect as well.
The other issue is fracture. Very real. We had 13 fractures in 1,000 patients. This is double our posterior approach cohort. And what we found was that 9 of them were over 70 years, under 25 BMI, females. So, we’ve changed our practice and in that age cohort, we only use cemented femoral stems. We eliminated this issue.
The learning curve is real. But the issue is not approach, it is newness and unfamiliarity. The better and more consistent you are with your clinical results, the less benefit you will have to change.
Dr. Springer: First I must state that I really have no problem with the anterior surgical approach. I think if we want to say it’s different, then fine, let’s say it’s different. I think what most people and surgeons have a problem with is the sensationalism and the overzealous promotion of this approach. And I would argue that emerging evidence would suggest that this is a high risk, no reward operation.
So, what are the benefits and concerns? Resource utilization, dislocation risk, better function…is it safe? I for one am certainly waiting to be overwhelmed by the literature.
Resource utilization… my operating room during a posterior approach…myself, my PA, my scrub tech…it’s one of the most relaxing operations I do.
Every time I walk by my partner’s operating room, it looks like they were in there separating Siamese twins or something like that much less doing a hip replacement.
And then we have the issues with the X-ray and the table. In our place, fluoro is billed out in one-hour increments, so even if you use it for one minute, it’s a $1,000 charge. Now, I will say I’ve found these tables to be very comfortable between cases for taking a nap and stretching out my tight hamstrings.
What about evidence for better stability? The initial data suggested higher rates of instability with the direct anterior approach, probably somewhat relative to the learning curve. The three prospective randomized studies (Taunton et al. and Barrett et al.) don’t show any difference. The registry data published in the Journal of Arthroplasty this year—out of Michigan (Maratt, et al., 2016)—no difference in dislocation rates. Both approaches less than a half a percent.
What about better functional recovery? Well, I think most people got excited about some of the initial data that came out comparing this to an anterior lateral approach where you take down a third of the abductors. Even in those studies there was no benefit functionally beyond six weeks in those patients.
What about versus the posterior approach? A meta-analysis—17 studies, 2,300 patients (Higgins, et al., 2014)—conclusions: current evidence comparing outcomes following anterior versus posterior total hip does not demonstrate clear superiority of one approach over the other.
And let’s look closely at thes prospective randomized studies, because if you just read the abstracts, you’ll be swooned. If you read the articles, you’ll be more reserved.
Bill Barrett’s study—walks further on day one and day two; did the direct anterior; less pain but took the same amount of pain medicines; stayed three-quarters of a day less in the hospital; and sub-function scores of their HOOS and HSS scores were better at six weeks as Jose demonstrated. No difference in any parameter at three months, and yet they had longer operative times; more blood loss; longer incision; and worse cup inclination—when using fluoro.
A study out of our institution where we looked at 12 different parameters, prospectively randomized by a single surgeon. The only difference was quicker cessation of gait aids with the direct anterior approach. The mental scores favored posterior approach. And there was no difference in any other parameter at any other time point during this study that was measured.
And in the study that Jose brought up at AAHKS I was able to get a hold of the paper…again if you read the abstract you’d have swooned. A hundred patients randomized DA [direct anterior] or posterior approach, but if you look at the numbers only a three to six-day difference in gait aids and walking distance. They did have better advanced activity at two weeks, but no difference in any parameter beyond two weeks.
And I think part of this is that these are expert surgeons doing these cases.
When you read the literature, you have to take into account expertise bias. That’s a surgeon with a higher competency and a higher volume, has better familiarity and is more likely to have better outcomes.
But is this generalizable to the community where 60% of primary total hips are done by surgeons that do less than 25 a year?
We’ve seen concerns in the literature for community surgeons adopting direct anterior approach with, I would argue, extremely high complication rates.
No difference in resource utilization on post-acute care.
No difference in patient-reported outcome measures.
Higher wound and infection complications in the direct anterior approach particularly in the obese patient population.
Early proximal femoral fractures in the total hips with the direct anterior approach.
And I would also argue that I think the femoral side of this approach is a real problem, both with fractures and loosening.
We went back and looked at nearly 7,000 primary total hips. Very low overall revision rate between the two groups—1.5-2%—and these were all patients that had early revisions at less than five years. No difference in the overall revision rate by approach; slightly higher in the direct anterior group. But a dramatically higher rate of femoral failures for aseptic loosening, particularly in the Dorr Type A femurs along with a higher rate of return to the operating room and revisions for other reasons in the anterior approach group.
Remember, total hip replacement was deemed the operation of the century and we should not let short-term objectives compromise our long-term performance.
Let’s be honest about a high risk, no reward operation that essentially serves as a great marketing tool. And not forget the principles of total hip, which are long-term fixation; low wear; and be very careful about allowing a small part of the procedure—the approach—to dictate the whole procedure.
Moderator Thornhill: Those were both very good. And Jose, I truly congratulate you. I think you gave a very, very balanced perspective, which I think is wonderful.
Bryan was talking about the problems of using the table, but you don’t use a table, at least not as it showed in your pictures. Tell me about that. If somebody comes to you and says, “I’m going to start anterior hips, should I do this with a table or not a table, and why?”
Dr. Rodriguez: A table gives you a mechanical advantage. People that use the table and don’t know how to do the operation, have complications. So, you must understand the soft tissue aspect before the table becomes truly useful.
Moderator Thornhill: Do you think it is the lack of exposure to the femur or do you think it’s the predilection to use a shorter, stubbier stem because it’s easier to get in? Is it stem-dependent or vision dependent?
Dr. Springer: Jose showed their data about peri-prosthetic fractures and, in our data, our rates of aseptic loosening were increased, but peri-prosthetic fracture wasn’t any different. My suggestion is…you put a bunch in too tight, you break a bunch of femurs, so then you go in the opposite direction. You start putting them in too loose and you have a bunch of them loosening. You’re chasing your tail a little bit. I do think it is somewhat stem-dependent/design-dependent.
Moderator Thornhill: Jose?
Dr. Rodriguez: The exposure of the femur is clearly the greatest challenge and there are certain body morphologies in which it is particularly challenging. As far as the stem, there’s not going to be a lot of bloodshed here because Bryan and I basically believe you should absolutely not change your stem based on your choice of exposure. Learn how to do a stem and learn how to do it with that exposure. There is risk in changing a design that has long years of experience. Shortened stems by themselves are not necessarily good.
Moderator Thornhill: Okay, so why did you change and go to the anterior approach?
Dr. Rodriguez: Both of my mentors—Chit Ranawat and Reinhold Ganz taught me you’ve got to be able to get into the hip every single way. So, because of my work with peri-acetabular osteotomies, I had comfort in the front and I had a board member who said I want this and I couldn’t offer it to him. So, I decided I wanted to learn. That’s my personal answer.
Moderator Thornhill: So would you agree that if you’re happy and your results are good, and you’ve looked at them with a mini-posterior approach, there’s no need to change to anterior?
Dr. Rodriguez: What I stated is the better you are at what you do, the less benefit there will be to change because when you change there will be a definite drop in your clinical outcomes until you understand what you’re doing. It’s like starting all over again.
Moderator Thornhill: Bryan, I’ve got a real problem though. I tend to use a mini-posterior approach. Most of my patients don’t go home with any precautions. Yet, when they come back at four weeks, they’ve been told not to bend more than 90 degrees and sit on the toilet, and one floor up, and not do anything. Do you have that same problem?
Dr. Springer: We have that exact same problem. It’s a cultural issue with the therapist. It’s about not wanting something to occur on their watch. We still fight that exact same issue of the therapist wanting to give them precautions.
Dr. Rodriguez: For what it’s worth, so do I.
Moderator Thornhill: Oh, good. It’s interesting. I want to thank both the speakers.
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Senior Editor: Jay D. Mabrey, M.D., whose 35 year career in orthopedics included residency at Duke University Medical Center, service in the United States Army Medical Corps, Fellowship at the Hospital for Special Surgery and a long, distinguished career at Baylor University Medical Center where, in addition to his overall leadership at that institution, developed the Joint Wellness Program that helped patients get up after surgery more quickly, developed the first virtual reality surgical simulator for knee arthroscopy and chaired the FDA Orthopaedic Device Panel, is Orthopedics This Week’s newest contributing writer and editor.