“Keep it simple, ” says Tom Sculco. Posterolateral is easy, well known, and is relatively atraumatic if done well.” Wolfram Mittelmeier, M.D. notes, “But how exactly do you perform a posterior approach? MIS? It’s important to note that high volume surgeons have better results with this.”
This week’s Orthopaedic Crossfire® debate is “The Posterior Approach: Optimizes THA [total hip arthroplasty] Outcome.” For the proposition is Thomas P. Sculco, M.D. from Hospital for Special Surgery in New York; against the proposition is Wolfram Mittelmeier, M.D., from Rostock University in Germany. Moderating is Clive P. Duncan, M.D., F.R.C.S.(C) of the University of British Columbia.
Dr. Sculco: “There are many surgical approaches to the hip and many are quite good. The most common approaches in North America are anterior and posterolateral. I like the latter because it is commonly used in hip surgery, it can be easily extended, there is less blood loss, and it’s a quick procedure. Its main disadvantage is that it can increase the dislocation rate.”
“We reviewed almost 1, 500 of these hip replacements and followed up for 8.5 years; the skin incision was 8.4cm. We looked at their radiographic criteria and saw that the findings were quite good; the cement technique in those that were good were usually in the A or B category. And the stem was in a neutral position in most patients. The dislocation rate was small (1.2%), femoral fracture was 0.3%, and neuropraxia of the sciatic nerve was 0.3%. The problem there was that we tried to push the envelope and made the incision and approach too small, and we put undue stress on the sciatic nerve. Wound complications were amazingly uncommon. Younger patients can usually come off the cane in two or three weeks, and recovery is expeditious.”
“There are 62, 000 web sites advocating the use of the anterior approach. The claims that have been made are that it’s tissue-sparing, there is less pain, and faster recovery. However, there is little evidence to support these.”
“The disadvantages of the anterior approach are that in the U.S. a special table is often used, as is interoperative fluoroscopy. The femoral exposure can be difficult (particularly in male and heavyset patients); it also increases OR time. Then there is the question of whether complications are higher with this approach.”
“In a cadaveric study of the anterior versus the posterior approach (Meneghini, CORR, 2006) the researchers found muscle damage with both approaches (posterior: 18% versus 8% gluteus med/min; anterior: 31% tensor fascia lata versus 50% transected piriformis/conjoined). But obviously the muscle damage in the anterior approach was significant.”
“In a study by Pilot (Injury, 2006) they looked at another way to look at muscle damage…H-FABP [heart-type fatty acid binding protein], which is a muscle protein. You can evaluate the levels of muscle damage based on the levels of this protein. There was no difference in the posterolateral versus the anterior approach.”
“Regarding dislocation, several large series of anterior approaches to the hip showed roughly the same thing: 0.96% (Siguier et al.), 0.61% (Matta et al.), 1.3% (Kennon et al.), 1.5% (Sariali et al.). My dislocation rate was 1.2% with the posterolateral approach.”
“Joel Matta is the biggest advocate of this approach in the U.S. He has a 2.4 % fracture rate with the anterior approach, which is much greater than we see with the posterior approach. Much of this has to do with the manipulation of the femur to get good femoral exposure with this anterior approach. And the use of a special table puts the limb in a very un-physiologic position, and, I think, leads to potential fracture…especially in older patients.”
“Then there are problems in the anterior approach with lateral femoral cutaneous neuropraxia. In a paper by Goulding (CORR, 2010) as many as 80% of the patients noted numbness in the distribution of that nerve. And not all of those patients fully recovered. In a paper by Woolson et al. (Journal of Arthroplasty, 2009) looking at community surgeons using this technique the complication rate was 9% and the surgical time was at least two thirds that of the posterolateral approach.”
“In conclusion, keep it simple. Posterolateral is easy, well known, and is relatively atraumatic if done well; blood loss is reduced. It is a reasonable way to go.”
Dr. Mittelmeier: “I love the anterolateral approach, but the question is, ‘What is the best approach in which hands?’ You can do different posterior approaches: minimally, maximally, or better or less. The question is, ‘How do you perform it?’”
“Witzleb’s study from 2009 on the posterior versus the lateral approach there was a shorter operating time with the lateral approach (67 minutes versus 76 minutes). And if the implant is positioned incorrectly (cup or stem) the results can’t be good. You must have good orientation, and I think the anterolateral approach has an advantage.”
“Do we need MIS [minimally invasive surgery] approaches? In a 2006 study by Lafosse et al. the complication rate was significantly higher using an MIS approach. As for the learning curve in MIS approaches, they are a big problem in my opinion. A small incision can cause big damage.”
“Looking at complication rates using the registries from England and Wales, we see that the overall seven year rate of revision for any reason was 1.7%. The risk of revision was significantly higher in total hips in smaller head sizes (<28mm). I believe other factors are more important than the approach. The overall risk of revision was independent of surgical approach.”
“Sköldenberg et al. (Acta Orthop, 2010) showed that the posterolateral approach was the only factor associated with an increased risk of dislocation.”
“It’s important to note that high volume surgeons have better results. The biggest problem we have is that many surgeons perform the surgery only a few times per year. ”
Moderator Duncan: “Wolfram, by anterolateral do you mean transgluteal, between the posterior border of tensor fascia, or the anterior border of gluteus medius?”
Dr. Mittelmeier: “The posterior border of tensor fascia…it’s a modified Watson Jones. It’s a typical approach we take in Germany.”
Dr. Sculco: “Wolfram’s points are well taken. The MIS incision is not for everyone. You must be an experienced surgeon before you attempt to do these operations through smaller approaches. You can teach this to residents and faculty—as we do—but you graduate the incision and the approach based on the size of the patient. So I don’t think you should be struggling, and I don’t think you should use a smaller incision just to make the incision smaller. You should be able to visualize everything that you’re doing. I agree that complication rates will be greater if you compromise the approach and visualization with a smaller approach. I also agree with femoral head size. I rarely use a femoral head greater than 32mm. Wolfram, what do you do to the gluteus medius and the minimus? Do you take it down? In the U.S. when the anterolateral approach is used the patients who came to me didn’t walk well…they limped. Is that a problem with your approach?”
Moderator Duncan: “One of the things here is language. ‘Anterolateral is often used by surgeons who take a direct lateral approach. The anterolateral—where care is given to protect the anterior border of the gluteus medius—it isn’t an issue.”
Dr. Mittelmeier: “If we go under the distal part of the gluteus muscle, you can make a small incision of 5mm. The bigger problem with the anterolateral approach is to make a good incision in the capsule. You must resect the anterior part of the capsule…then it’s easy. If you go to the posterior approach you have to think about what to do with the piriformis muscle and with short external rotators.”
Dr. Sculco: “I create a posterior window with a trapezoidal capsulotomy, taking the external rotators down—the piriformis and the conjoined tendon—then I repair them directly back through the greater trochanter at the end of the procedure. So I close that posterior window after the procedure.”
Dr. Mittelmeier: “It’s not necessary to close the window with the approach I mentioned. It’s not necessary to restore and reconstruct the capsule. We resect the anterior half and that is enough…because the posterior dislocations are the biggest problem we have. If you have a good approach to the cup and you see good anteversion of the cup, as well as good lateral inclination it’s not necessary to close the capsule again.”
Moderator Duncan: “I think this is what each of you is saying is, ‘With either the anterolateral or posterolateral approach it is a gluteus sparing approach and if done well the patient will do well.”
“But if you are an A approach surgeon and you are a B approach surgeon you might hear, ‘Listen, I’ve got another approach called the C approach and it’s worth your while to learn it mid-career. That’s your point, Tom, with reference to the pure anterior approach…which is two finger breadths more anterior to what Wolfram is using.”
Dr. Sculco: “Wolfram, I’ve seen surgeons do the anterior/anterolateral approach and they excise that anterior capsule as part of their exposure. And that’s not very anatomic. You have a big hole anteriorly and that could create an instability problem. Is that not the case?”
Dr. Mittelmeier: “Out of the last 1, 200 cases in our hospital after a year, there were two dislocations with this technique. What’s important is what type of implant you use; do you like a straight implant like an Exeter stem? Then it’s important to think of the approach being a bit more posterior. I think the posterior approach is better in the straight stems. If you have a curved stem the anterolateral is easy.”
Dr. Sculco: “I disagree. I can put a curved stem in a posterior approach…or a straight stem. It’s easy to visualize and you could use any stem you want.”
Dr. Mittelmeier: “I agree. It’s about the anterolateral approach…it’s easier to do a curved stem.”
Dr. Sculco: “I think it’s a bit harder in the anterior approach…to expose the femur. Don’t you think?”
Dr. Mittelmeier: “No. Straight stems in these approaches—anterior—is not possible.”
Moderator Duncan: “Tom, now you’re away from North America you may be less reluctant to comment on the market pressure there is on surgeons to consider changing their approach.”
Dr. Sculco: “I think you should do whatever approach you’re trained on and good at. I just feel that the posterolateral approach is so simple and quick, with low blood loss and a fast recovery. But do what you’re trained on and successful with.”
Moderator Duncan: “Wolfram, do you position your patients supine or lateral? Are there any advantages to the supine for accuracy, cup position, and leg length?”
Dr. Mittelmeier: “We put the patient in a flat position, then we turn the leg. We don’t need special tools or instrumentation.”
Moderator Duncan: “Thank you both.”
Please visit www.CCJR.com to register for the 2014 CCJR Spring Meeting, May 18 – 21 in Las Vegas, Nevada.
