“The anterior approach has a faster recovery and optimizes outcomes when compared with a direct lateral approach, ” says Keith Berend. Hold on, says Tom Sculco. “The posterolateral approach is a common approach that can easily be extended, involves less blood loss, and is expeditious.”
This week’s Orthopaedic Crossfire® debate is “The Mini-Anterior Approach: Optimizes THA Outcomes.” For the proposition is Keith R. Berend, M.D. from Mount Carmel Health System and Joint Implant Surgeons in Ohio; against the proposition is Thomas P. Sculco, M.D. from the Hospital for Special Surgery in New York. Moderating is Robert T. Trousdale, M.D. from Mayo Clinic.
Dr. Berend: “There are results in the literature over the past decade that taught the benefits of the direct anterior approach. Such as: it’s safe and reproducible, there may be less blood loss, less pain, shorter hospital stays, fewer readmissions, perhaps better implant positioning because of visualization or fluoroscopy, less muscle damage, and overall better recovery compared with other approaches.”
“The problem is that there are an equal number of studies that are very well designed and performed and that show that it can be dangerous and difficult to teach…that show a chance of more blood loss, there’s no benefit over more common approaches, there are more outliers in terms of implant positioning because of decreased visualization, perhaps more or different muscle damage, and that there’s no significant difference between recovery with an anterior approach versus some of the other approaches.”
“My JBJS study from 2009 compared the less invasive direct lateral approach with my early experience with the anterior supine intermuscular (ASI) approach. We found that early on there was a slight trend toward picking lighter patients for this approach—although I don’t do that any longer. The OR time was very similar in both of these approaches, but there was more blood loss intraoperatively with the ASI. And there was nearly double the transfusion rate with that approach (although it wasn’t statistically significant).”
“We did see a slightly shorter length of stay, a significantly better discharge deposition (meaning that patients were more likely to go straight home and less likely to need rehab). And we showed that preoperatively their Harris Hip Scores were identical…but that as early as six weeks those scores were already better with the anterior supine compared with a muscle-splitting direct lateral.”
In our initial series—published this year [2013] in Instructional Course Lectures—we had 1, 035 consecutive ASI on 906 patients. The transfusion rate leveled off at around 5%, we had an average 40-month follow-up, and there were only four complaints of lateral femoral cutaneous nerve issues. There was a 2.4% revision/reoperation rate, only four dislocations, and only one deep infection in this unselected series of over 1, 000 patients.”
“So we concluded that the ASI has a faster recovery and optimizes outcomes when compared with a direct lateral approach. In the early postoperative period periprosthetic fracture occurs in 0.86% of cases. This may be an actual increased risk with the anterior approach, but it’s just on the outside of that which has been published in other series and registries. Infection is extremely uncommon with this approach, and it seems to be less than that published in registries and other large series—0.1% as compared to 0.6-3% in certain registries.”
“Neither Dr. Lombardi nor I have done a posterior approach in 25 years. But if we were to randomize our patients, the question is, ‘Having done thousands of anterior approaches and no posterior approaches, which would end better?’ Clearly, the anterior approach in our hands would be much better. Perhaps you could design a study where it’s not surgeons who have no experience, and you randomize patients into the hands of surgeons who do a posterior approach and those who do an anterior approach. The question remains, ‘How many cases must you do to be proficient? How many years of practice do you have to have under your belt in order to say that this is going to be a fair comparison…and that there’s not a learning curve bias, a patient selection bias, or even a surgeon experience/skill bias?”
Dr. Sculco: “The posterolateral approach is a common approach that can easily be extended, involves less blood loss, and is expeditious. Its main disadvantage has been a question of increased dislocation rate.”
“Some years ago we looked at about 1, 500 hips done through this less invasive approach, followed out to 10 years. Radiographically, we found that the position of our stem and socket were quite good. We did have a 1.2% dislocation rate, five femoral fractures, and five neuropraxias (we were pushing this procedure through too small an approach). There were very few wound complications. So last week I looked up Internet searches for the anterior approach, and found over three million sites; there is a tremendous interest in this approach.”
“The claims made are that it’s tissue sparing, involves less pain, and provides faster recovery. But there is not a lot of evidence to support these assumptions. The disadvantages of the anterior approach? You need a special OR table as well as intraoperative fluoroscopy; femoral exposure is more problematic, OR time is increased in many studies, and complications may be greater.”
“Is it more muscle-sparing? In 2006 a cadaveric study came out from Dr. Menghini of the Mayo Clinic. There was significant damage to the tensor (31%) and the conjoined/piriformis tendon through the anterior approach (50%).”
“Dislocation rates…Siguier showed 0.96% in 1, 037 THR [total hip replacements]; Matta found 0.61% among 437 THR; Kennon found 1.3% among 2, 132 THA [total hip arthroplasty]; Sariali found 1.5% among 1, 374 THA; these are similar to the 1.2% I found among 1, 465 THA from my series.”
“Periprosthetic fracture rate…Dr. Matta had a 2.4% fracture rate—significantly greater than the 0.3% posterior fracture rate that I reported.”
“In videos of Keith doing the procedure with Dr. Anderson, I noted what I call the ‘fluoroscopy machine dance.’ This is where the fluoroscope comes in, goes out, comes in, goes out throughout the procedure. Then there was the complete excision of the anterior capsule and much of the superior capsule. That is not tissue-sparing. Then there is this medieval winch that Keith puts on the table…the hook grabs the femur and pulls it up into the wound…a bit primitive.”
“Then there’s what I call the Hobbit—the diminutive femoral prosthesis that you can stick in because you really can’t see very well into that femur. And Keith said that his learning curve is 35 cases, and he certainly is an expert at this approach. So if the average orthopedic surgeon in the U.S. does 25-50 hip replacements a year it’s going to take one to two years before you are comfortable.”
Moderator Trousdale: “Can we agree that both exposures are pretty reliable?”
Dr. Sculco: “Yes.”
Moderator Trousdale: “Can we agree that both cause some muscle damage?”
Dr. Sculco: “Yes.”
Dr. Berend: “Yes.”
Moderator Trousdale: “Can we agree that that the recovery rate may be the same or may favor the direct anterior approach (at least the first six weeks)?”
Dr. Sculco: “It’s about the same.”
Dr. Sculco: “It’s about the same. The only question is, ‘Do you use hip precautions on your posterior approach?’”
Dr. Sculco: “I do, but we’re more conservative than we need to be.”
Moderator Trousdale: “Tom, your precaution may be if you use one to avoid hyperflexion, abduction, leg propulsion for posterior instability. Keith, is it not rational for the direct anteriors to tell them to avoid extension and external rotation of the hip joint?”
Dr. Berend: “The only thing the physical therapists teach them differently is how to get in and out of bed.”
Moderator Trousdale: “Tom, why is blood loss less with a posterior approach than with an anterior approach?”
Dr. Sculco: “I think the suction is less. It’s an atraumatic, clean approach. You don’t cut much muscle; you release piriformus and conjoined tendons. A little bit of the quadratus is released, but not much. And usually there aren’t a lot of big vessels that you can damage. We’ve documented that blood loss is significantly less with this approach.”
Moderator Trousdale: “So where does the blood loss come from? It can’t be the socket or the femur because that should be the same (theoretically), right?”
Dr. Sculco: “It may or may not be. If you hyperextend the table…the leg, could there be some type of venous phenomenon that causes more bleeding from the capsule or the femur during femoral prep. That’s one theory. The other theory is that in any of the studies we’ve done looking at the changes in blood loss, the most important variable is hypotensive anesthesia—Tom’s group pioneered that. If we use this there’s such little blood loss anyway; adding tranexamic acid…blood loss isn’t an issue for me regardless of the approach.”
Moderator Trousdale: “Keith, why would the infection rate be lower with the direct anterior approach?”
Dr. Berend: “There may be a surrogate variable in that dataset I presented. I was selecting out thinner patients. Using any lateral based approach on the obese patient you have a lot more tissue to heal…there’s a lot more fat and a longer incision versus the anterior approach where there’s little fat.”
Moderator Trousdale: “Would you agree that if you have a complex hip that the posterior approach may win out if you need more extensile exposure?”
Dr. Berend: “No question on the femoral side. I will say that I’ve gotten more comfortable with complex acetabulum issues.”
Moderator Trousdale: “Both approaches seem to work well. Why do you think the anterior approach—if it’s so good—hasn’t been more widely adapted?”
Dr. Berend: “Because the posterior approach is outstanding and if you’re happy with your results and you’re not solving a problem there may not be a reason to change.”
Dr. Sculco: “There’s a lot of marketing out there, and patients say to me all the time, ‘I want you to do the anterior approach.’ So a lot of young surgeons going into practice are being pushed to do it.”
Moderator Trousdale: “Thank you gentlemen.”
Please visit www.CCJR.com to register for the 2014 CCJR Spring Meeting, May 18 – 21 in Las Vegas, Nevada.
