Direct Anterior Approach FAQs
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Why did you change to a Direct Anterior Approach?
I performed posterior approaches for hip replacements for 15 years, as I was trained to do in my residency and total joint fellowship. This is how almost all US surgeons perform the operation today. I made the switch for several reasons. I was not happy that I had a dislocation rate similar to large studies, about 2%, and that I made a few people too long on the operative side. I saw both problems relatively frequently (and still do) on referral from other surgeons. These are both issues in posterior approaches. After exploring other options for “minimally invasive hip approaches” I learned the DA approach in 2005, and haven’t turned back.
Did making the change improve your patients’ outcomes?
Yes, at Sharp HealthCare we keep a very robust database on our outcomes. My hospital stays decreased, my dislocation rate decreased to about1/500, I have a rare mild leg length discrepancy, and my objective patient satisfaction scores are very high. Additionally, I know my personal X-rays results show position of the implants has improved substantially, and there are many studies showing that improved alignment leads to increased longevity of the implants (similar to tires lasting longer if the car is in good alignment).
Why are the dislocation rates reduced?
The most important factor is probably the direction from which we approach the hip. In coming through the front of the hip, the defect is created such that to dislocate the hip one has to extend the hip backwards while rotating the foot out. This is not a position a person puts themselves into normally. This is opposed to the posterior approach, which is unstable in flexion and internal rotation, a position one uses to put on shoes, work in the garden or get in and out of out of chairs, cars, or bed.
The second factor is the fact that no stability muscles are being disrupted, as the complete hip exposure is done by spreading muscles instead of cutting them. Additionally, with availability of real-time X-ray, the implant position is very controlled during the operation, an important variable in dislocation rates and long-term results.
What gives you better ability to control leg lengths?
Leg length discrepancies are a big patient satisfaction downer. In the same way that we can control cup position, we can control leg length. With the OSI table, I can slide a c-arm fluoroscopy unit in and obtain a real time X-ray image of the hip. I can then compare it to the other side, and based on that I can tell if the hip length is as close as I can get it, both in length and offset. That is very hard to do with a posterior approach, and not as accurate or reproducible. I can trial temporary implants multiple times until I get the combination that gives me the ideal result.
Why do you use X-ray in the Operating Room? I’ve heard that you have to use it.
I use the C-arm unit because I can, not because I have to. I am able to provide the patient the best possible position of their implants for stability and leg length possible because I have access to real-time images of their hip during any point in the case. You simply can’t do that with any other hip approach.
Why don’t other surgeons make the change?
To be honest, I’m not sure. I’ve never thought about going back due to the obvious improvement in my results. For some surgeons, they have done it the same way for years, and they feel their results are good, and at the point they are in their careers they don’t want to learn a new way to do hip replacements. Some don’t want to wear lead protection for the C-arm X-ray. Some don’t have the support of their hospital to invest 6 figures in a new table for the OR. Some felt that large head technology was a better answer to avoid dislocations. Nationally, dislocation rates are down with large head metal-metal bearings, but unfortunately the revision rates are higher now due to metal ion reactions and other related complications. Head size is not very important in DA hips due to the inherently low dislocation rates. The surgical time is a little longer as I take multiple Xrays and analyze them, and make changes to the implants and re-image them each time. But, all these things are important to me, and my patients. So, I took the time and effort to retrain after 15 years of doing posterior hips, wear lead clothes, and take more time doing the case because I think the upside is worth it.
Does everyone get a great result?
No. Everyone is different. Some patients are very healthy and athletic and are out of the hospital the next day and back to their jobs and normal activities in a couple of weeks. Others have multiple medical and orthopaedic issues and have a harder time recovering, so are in the hospital and rehab centers longer. This is true for anterior or posterior approaches. My personal experience is that each category of patients does better with the DA approach than they would have done compared with the posterior or antero-lateral approach.
Additionally, there are complications associated with any total hip replacement, as these are major operations. Infection, bleeding, nerve or vessel damage, blood clots in the legs or lungs, and anesthesia reactions can occur. I don’t believe any of these are any more or less frequent with an anterior approach.
Why do patients recover faster with this approach?
I believe it is the muscle splitting approach and the inherent stability of the implants, which enables me to eliminate the “hip precautions” I used with the posterior approach. There is no “negative feedback therapy,” as the therapists and I used to badger the patient to avoid positions of their hips that are inherent to activities of daily living (ADL’s). They just get up and use their legs as they are used to, sleep without special pillows between their legs, get in/out of chairs and on/off toilets without special attention to body position. So, the recovery is just faster because they can do what they want to do without being (correctly) paranoid. And, though it is hard to quantify, the average patient has less pain in my experience, though again every patient is unique in how they respond to surgical pain. Finally, with less muscle disruption, there is less guarding and weakness and in my personal experience the patients just seem to trust the hip more and therefore want to be more active sooner after surgery.
Who is a candidate for an anterior hip approach?
Everyone in my practice is a candidate for an anterior approach. Once I started using this approach for my hip replacements, I haven’t ever gone back to the traditional approach. There are rare congenital anatomic situations that are better performed using other approaches. The patients that have the most risk due to the approach are the obese population, though they are higher risk with posterior approaches as well. Additionally, many revisions (removing old hip replacements) are done posteriorly, though the indications for anterior revisions are increasing.
The Direct Anterior Approach for total hip replacement is a tissue-sparing alternative to traditional hip replacement surgery, providing the potential for less pain, faster recovery, and improved mobility. The technique allows the surgeon to work between the patient’s muscles and tissues in the front of the hip without detaching them from either the hip or thighbones.
Keeping the muscles intact also helps to prevent dislocations. With the Anterior Approach, the surgeon uses one small incision on the front (anterior) of your hip as opposed to the side or back.
The Anterior Approach procedure for total hip replacement has become more popular due to its potential benefits:
- Faster recovery time because key muscles are not detached during the operation. Other procedures require cutting or disturbing the important muscles at the side or back of the leg. The Anterior Approach is known as a tissue-sparing procedure because it minimizes muscle damage.
- Fewer restrictions during recovery. Although each patient responds differently, this procedure seeks to help patients bend their hip more freely and bear their full weight immediately or soon after surgery. Conventional hip replacement surgery restricts the patient’s movement (hip flexion, pivoting, or twisting of the leg) and range of motion for 6–8 weeks following surgery to prevent dislocation of the hip while the soft tissues heal and muscles strengthen. Less restrictions on the patient’s activity leads to faster return to normal activities, with more focus on getting better, rather than the negative focus on preventing dislocations. A patient can sit like they want, sleep like they want, and exercise as much as they want early on without the stress of worrying about dislocating.
- Reduced scarring because the technique allows for a smaller incision and since the incision is in front, the patient avoids the pain of sitting on the incision site.
- A high-tech operating table is used to help improve surgical access and allow intraoperative real-time x-ray. This is a key for the surgeon to confirm implant position and leg length. Leg length discrepancy is not uncommon in standard operative approaches to the hip, and real-time feedback of implant size and position is important in consistency of implant positioning that in turn is known to improve long-term survival of the implants (much as having a car in alignment improves the longevity of tires).
Dr. Hanson has been performing this procedure since 2005 and has been extremely satisfied with his choice to switch from the conventional posterior approach to the Anterior Approach because of the high patient satisfaction he has experienced. He performs about 100 of these operations a year and now only uses the older approach on primary hips when the patient is not a good candidate for the Anterior Approach. Dr. Hanson uses the techniques as taught to him by Dr. Joel Matta in Los Angeles, utilizing the OSI Hana Table.