This week’s Orthopaedic Crossfire® debate was part of the 16th Annual Current Concepts in Joint Replacement® (CCJR) – Spring meeting, which took place in Las Vegas this past May. This week’s topic is “The Anterior Tabled Approach: First Among Equals.” For the proposition is Paul E. Beaule, M.D., F.R.C.S.(C), Ottawa Hospital, Ottawa, Ontario, Canada. William J. Maloney III, M.D., Stanford Hospital & Clinics, Stanford, California opposing. Moderating is Thomas P. Sculco, M.D., Hospital for Special Surgery, New York, New York.
Dr. Beaule: When you decide on choosing a surgical approach, there are certain principles you need to think about. Proper patient positioning, having access to the involved area for the desired procedure and avoiding damage to functionally important structures. It can be extensile but these principles minimize complications and are cosmetically acceptable.
Now some would argue this is purely basic science with no true impact potential in function, but then you have two randomized trials comparing the direct anterior approach to posterior approach where most of the advantages are known in the first six weeks. You also have two other studies that are matched cohort studies, one involving the same surgeon comparing the direct anterior to the posterior approach where he found the direct anterior to be superior. And the series from the Mayo which involved two different surgeons where the mini-posterior was found to be superior to the anterior approach in terms of recovery time.
I think the anterior approach optimizes patient recovery.
In terms of minimizing complication, dislocation is still a major problem, up to 6.9% following the posterior approach, as well as component orientation. Optimization is difficult. A recent paper in 2001 showed that only 47% of hips were in the acceptable range. And if you look at the paper from Steve Woolson with a community practice, the average number of primary hips per month was quite low. There were no incidences of dislocations and 79% of these hips have the acetabular component in optimal position.
If you look at our first 200 at our center, we had an overall complication rate of about 4% that were directly related to anterior approach. This compares quite favorably to the two incision approach and also from the Jewitt series with the first 800, who had 4% compared to 5.8%.
So in conclusion, I think the anterior approach is first among equals. It does meet your desired outcomes in relieving pain, restoring function and mobility, in terms of proper implant position and quality control, recovery time is minimized. It’s a reproducible technique. Really at the end of the day these surgeons have the happiest smile.
Dr. Maloney: So why the anterior approach and what are we trying to do when we change approach? Well, Paul talked to you about the reduced risk of dislocation. It’s an intermuscular approach, excellent view of the acetabulum, less overlying adipose tissue in an obese patient and the patient is supine so if you’re not using a special table you can get a good look at leg lengths.
But there are disadvantages. It’s difficult to visualize the femur. Lateral femoral cutaneous nerve injury, as Paul talked about in about two-thirds of the patients. The radiation exposure. Leg length equalization if you’re using the fracture table can be a challenge. And there’s a learning curve. The problem that I have with this technology is that it was played out in the marketing data and not in the scientific data.
So people adopted the technology because their practices were suffering.
A paper done by our faculty and fellows (Woolson, et al., 2008) looked at what happens when you introduce new technology into a community practice. Remember in North America, more than 50% of the hips are done by people who do one or two hip replacements a year.
The study was a cohort study that looked at a standard posterior approach in a group of five surgeons and compared that to an anterior approach. It was consecutive. It used the data from hospital charts. Inpatient data as well as data on readmissions.
We asked the surgeons, ‘Why did you do it?’ The #1 reason was competition from minimally invasive surgeons in the community. Four of the five surgeons in this group visited one of the innovators and none of them had cadaver or lab training.
Surgeon #1 increased his volume by 5x. It was a big marketing campaign about being the #1 hospital in the area doing the anterior approach. They also changed other parts of their surgical techniques. They changed the type of fixation. They went from 62% to 83% cementless. They changed their head diameter. They went from 8% to 73% using femoral heads larger than 28mm. And they changed the bearing type. In terms of hard bearings they went from 7% ceramic-on-ceramic/metal-on-metal to 40%. So they changed a lot of things in the operation.
If you look at their data the use of regional anesthesia went up. The use of drains went up. There was a higher chance of a hematoma. Post-op protocols changed but screws and cups stayed the same. If you look at the hospital results in terms of the surgical time for a standard posterior approach the anterior approach took significantly longer. Anesthesia time significantly longer. Length of stay, significantly shorter.
Now I can argue that length of stay is not due to the surgical approach, it’s due to what you tell the patients ahead of time. A lot of that is when you tell the patient they’re going home and how you set up your rehabilitation protocol. I don’t think it’s directly related to the surgical approach.
What about the learning curve? The learning curve did improve from the first 52 cases to the second 52 cases. Time went down. Length of stay went down and estimated blood loss went down.
What about the fracture rate? Well, they had a fairly high fracture rate through a standard posterior approach—about 3%. It was about double that in terms of the prevalence during the learning curve with the anterior approach and calcar fractures were pretty low. The greater trochanteric fractures are a problem.
There are some problems—and this is true of every approach, but I think when you change your approach, it’s more likely to happen.
This is where I have the problem. Surgeons do more cases. Hospitals make more money. But they don’t mention the complications. They don’t talk about the learning curve.
Moderator Sculco: The lines have been drawn, Paul, so let’s turn to you first. Bill raised a lot of questions and maybe you could address some of those. Talk about that learning curve because I debated Keith Berend last year and he said that to be good at this direct anterior approach, you have to do 100 cases. Is that your feeling as well?
Dr. Beaule: I think it’s almost a debate about learning curve and our profession not having the capacity to adopt new techniques after we graduate from residency. I fully agree with Bill that the learning curve is not being approached properly. But I don’t think it’s necessarily because of the anterior approach. The anterior approach illustrates that issue of learning curve and our capacity for our profession to learn new techniques. I think it’s a fine balance. But I don’t think the anterior approach in and of itself leads to higher complication rates overall, if done properly.
Moderator Sculco: Are there any patients you would not use the anterior approach, older patients, particularly where you’re worried about the bone quality. How about male patients who are very muscled?
Dr. Beaule: I think they’re difficult with any approach. I think the osteoporotic bone where you want to do a cemented stem is probably better through the posterior approach. People who have had complex deformities of the femur, the posterior approach is more reliable in that regard because you’re not sure what kind of femoral fixation you’ll have to deal with. These are certainly cases where the posterior approach is preferable.
Moderator Sculco: In your practice, what percent are anterior and what percent would be posterior?
Dr. Beaule: 95% to 98% are anterior.
Moderator Sculco: About trochanteric fractures. So if you get a fracture while you’re doing an anterior approach, do you have tricks about fixing that fracture or do you find that to be an issue or not?
Dr. Beaule: The main issue we’ve had is with the calcar fractures. One trick you can do is to put a 3.5 screw right across and you have nice compression after you do the wires. So that would be one trick I would say has served me well in some cases.
Moderator Sculco: Bill, let’s come to you. The argument against the so-called posterior or mini-posterior approach has been the dislocation rate. If you look at the literature of a lot of the papers, anterior versus posterior, most of them or a lot of them are pretty similar, so you’re dislocation rate at Stanford for mini-posterior is what?
Dr. Maloney: It’s extremely low. I’ve had one hip dislocate in a primary situation since 2006 and it was a 36mm head, actually a physician who fell out of bed. Other than that, I think the dislocation rate should be less than 1%.
Moderator Sculco: I’ve tried the anterior approach. I just thought the “sweat factor” was much greater in terms of the exposure and visualization, therefore I abandoned it. What’s your feeling? Have you tried it?
Dr. Maloney: Allan Gross made a comment, ‘How can we take an operation that’s about as stress-free as it can be, with a success rate as high as it can be, and make it so difficult?’ I can do a pretty nice job with a mini-posterior and I can get it done in a reasonable amount of time and it comes out fine. I think the message is that you can do it with any approach. They’re doing a great study right now at the Mayo Clinic with Rob Trousdale, Mark Pagnano and Michael Taunton and there were no differences. The problem I have with this is that it’s been, again, marketed. There are unsubstantiated claims on the Internet about the superiority of the operation. It’s not a superior operation.
Moderator Sculco: So let’s take that one step further because a lot of people in the audience are sitting there and the patient comes in and says ‘Are you doing to do an anterior approach on me?’ I get this all the time and I’m sure you get it. What’s your response and what would you recommend to the audience in terms of how to handle that question if they don’t feel comfortable attempting the anterior approach?
Dr. Maloney: It’s the most common question I get…First thing is the patient looks at you and thinks you’re stupid because you don’t do the anterior approach. I’m in a fortunate situation, in a group practice. We have one guy who does it and he likes it. He was trained by Joel Matta. I send the patient down the road for that. But if you’re in a private practice it’s a difficult discussion and that’s what’s pushed a lot of people to do it. I just tell the patient this is what I do. This has been my experience and I’m happy with the outcomes, but I’m not doing that technology. You’re going to lose some patients if you don’t do it though.
Moderator Sculco: I think the message to the audience is that you have to educate the patient. The patient who is absolutely adamant that they want a direct anterior approach, I agree with Bill…just send them down the hall and you have people on your staff who will do them. But if you feel really confident and comfortable doing the posterior approach, you should do it. I think it’s been a great discussion. Thank you very much.
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