Melanie Cole, MS (Host): [00:00:00] Welcome to the podcast series from the Specialists at Penn Medicine. I'm Melanie Cole. And today, we're highlighting direct anterior hip replacement. Joining me is Dr. Kimberly Stevenson. She's an orthopaedic surgeon with Penn Medicine.

Dr. Stevenson, thank you so much for joining us today. I'd love for you to start by telling us a little bit about yourself and your role at Penn Medicine Chester County Hospital.

Kimberly Stevenson, MD: Thanks so much, Melanie. I'm Kim Stevenson. I'm an Adult Reconstruction Surgeon at Chester County Hospital with Penn Medicine. That basically means I'm a hip and knee replacement doctor. That's my specialty, is hip and knee replacement. And I also specialize in the hip in terms of trauma work as well. I'm the Section Chief of Orthopaedics at Chester County Hospital. So, I have a leadership position there as well, and I'm very passionate about the work I do, particularly in the field of hip replacement.

Host: Thank you so much for telling us a little bit about yourself now. Can you describe [00:01:00] for us the differences between traditional open hip replacement surgeries versus the minimally invasive options that are available today?

Kimberly Stevenson, MD: The principle of hip replacement is essentially the same regardless of approach. And so, it's important for patients and providers to understand that, at the end of the day, the end result is roughly the same. How I explain it to patients and others is how a surgeon executes the hip replacement can vary greatly.

There are several approaches to the hip, and the direct anterior approach is how I perform the majority of my hip replacements. Other popular approaches include the lateral and posterior approaches. But by no means is that an exhaustive list.

How the direct anterior approach really varies is it's an incision and approach more in the front of the hip. It's considered a muscle-sparing approach. So with several other approaches, including the lateral and posterior [00:02:00] approaches, the glute muscle, the large glute muscle is split in half to gain access to the hip. And in some approaches, sometimes even the smaller glute muscles under the glute max are released or split as well.

The main reason that matters is because this is a large functional muscle. So when that muscle is split, it requires perhaps additional rehab. By approaching the hip in the front or direct anterior, that muscle is not touched. So, we're coming more between muscle planes in the front of the hip and that leads to one of the main advantages of the direct anterior hip replacement, which is faster recovery.

Host: Thank you so much for pointing out those advantages to why you perform hip replacement that way. Now, speak a little bit, Dr. Stevenson, about patient selection. Who is it for and why?

Kimberly Stevenson, MD: I think the easier way to answer that question is who this surgery may not be perfect for. Typically, we select patients who have a smaller soft tissue [00:03:00] distribution around the hip. So, that does not mean a specific BMI or weight cutoff, but it does take into consideration where a patient carries their weight. The reason for that is because where the incision is can abut the groin fold. And so, our concern is that in patients who may have soft tissue overhang in that area, there may be difficulties with wound healing in that area. And that person or patient may not be an ideal candidate for this approach.

Host: So, what do you recommend once you've discussed with your patients in that shared decision-making, which is we know so important. What do you recommend that they do prior to surgery? Is anterior different than preparing for other types? Are we looking at prehab? What is it you want them to do?

Kimberly Stevenson, MD: I think the most important factor when preparing for hip replacement is trying to maintain your overall conditioning mobility as much as possible. I do not think prehab for direct anterior approach is any different than a posterior approach or a [00:04:00] lateral approach. I think maintaining the musculature and strength around the hip is important for overall rehab, but this does not differ between approaches.

Host: Dr. Stevenson, when we think of the hip joint, which as you said, large muscles surround. This is a joint that has a lot of motion. Where do comorbidities fit into your decision to use direct anterior hip replacement, for example, obesity? Or tell us a little bit about how you come to that conclusion. If someone is, for example, obese.

Kimberly Stevenson, MD: Right. So, that gets back to the question about soft tissue distribution. So again, it's not just a number, but where the patient carries their weight. Obesity certainly does increase the risk factors, period, for joint replacement. But specifically for direct anterior hip replacement, I'm worried more about risk of infection, risk of wound healing complications, as well as risk of fracture. And the reason for that is the incision's quite small regardless of the size of the patient. And so, the same amount of [00:05:00] work has to be done through that small incision. And if that patient has a larger soft tissue envelope, it may put extra stress on the bone and increase their risk of fracture. So, that's how obesity weighs in.

Additionally, I take care to examine the groin fold, the pannus, if there's any sign of a yeast infection or a soft tissue breakdown, again, may not be an excellent candidate for this approach. Another comorbidity that I consider greatly before surgery is osteoporosis or osteopenia. Again, getting back to the point that this approach may have an increased risk of fracture and those patients are already at risk for fracture. So, that does not preclude someone from this approach, but it is an extra consideration and a conversation I have with those patients.

Host: Dr. Stevenson, what about recovery? How does that differ from the various approaches for hip replacement? What's recovery like?

Kimberly Stevenson, MD: This is where I feel the direct [00:06:00] anterior approach has the biggest difference between other approaches. Many times patients are told that they have to follow what's called posterior hip precautions after hip replacement where they can't let their leg cross midline, they can't bend forward past a 90-degree angle, and this is typically for six weeks after surgery in addition to rigorous physical therapy.

With direct anterior hip replacement, I do not give my patients any hip precautions starting from day one. So aside from fall prevention, they can sleep how they're comfortable, sit how they're comfortable. They do not need any other alterations to the seats or chairs or couches they have at home. They can sleep in their own bed. And I think this is very liberating and freeing for the patient.

Additionally, many people don't require any additional physical therapy. Again, because this is a muscle-sparing approach. So of course, I'm a big advocate for physical therapy. If that's something both the patient and I feel they would do well with, I support that. But many, many patients do not need that additional formal PT. I [00:07:00] typically give this recovery timeline for patients.

I have them use a walker or a cane for the first week or two purely for fall prevention. And then, they slowly wean from that. And typically, by six weeks, patients are feeling fairly back to normal and ready to progress their activity from where they were even before surgery.

Host: Anterior hip replacement surgery has been described as gaining popularity in recent years, Dr. Stevenson, suggesting that it's not generally widely used yet. Can you explain a little bit what you think, in your own opinion, why this isn't being performed more widely? As you say, there are so many advantages and recovery time. Tell us a little bit about what you think.

Kimberly Stevenson, MD: I think that direct anterior hip replacement is only going to grow in [00:08:00] popularity. It is not new. It has been around since the 1940s. It was introduced as an approach in the 1940s And then, popularized by Joel Matta in the early 2000s, and he’s the one who really brought this approach and these techniques to the United States. He advocated and helped designed the use of a special table that facilitates this approach. And I would say that in the last 10 years, maybe even beyond that, the popularity of this approach has skyrocketed. I would say that the majority of trainees going through residency and fellowship learn this as one, if not the predominant approach they're learning.

So, I think it has just taken that amount of time to see those trends in training, which is then ultimately how many people go on to perform their hip replacements in practice. This approach has a very steep learning curve, meaning it takes a hundred plus cases to see a decrease in complications and a lower [00:09:00] operative time, which is a measure of proficiency with this approach.

And it's hard for surgeons who have been practicing for many years to not only take the time to learn this approach, which is a completely different way of executing a hip replacement, but then also getting those reps ideally with some guidance, when they're busy in their practice already.

So, I think this will only continue to grow because this is how trainees are learning in their residencies and fellowships. But I think that's been the limiting factor to this point.

Host: Finally, Dr. Stevenson, when is it important that providers refer their patients for direct anterior hip replacement at Penn Medicine? And give us some key takeaways, summary why you feel this is such an exciting approach for your patients.

Kimberly Stevenson, MD: Yes. Thank you. So, I really feel like any patient who is limited by their hip pain and/or stiffness is a good patient to consider for hip replacement. Specifically for a direct anterior hip [00:10:00] replacement, I believe anyone who is active, who has goals to become more active, or even patients who are at increased risk of dislocation, this is an excellent option for them because direct anterior hip replacement, again, may be protective against risk of dislocation, particularly in people at higher risks such as people with spinal fusions.

I think that, despite increased learning curve for this approach, the key benefits for a patient far outweigh the risk. Those benefits being faster recovery and potentially a lower risk of dislocation. Faster recovery, I'm typically telling patients within six weeks, they'll feel fairly back to normal, and new normal within three to six months, i.e., essentially forgetting they had a hip replacement. And I think that is the key differentiator between this approach and others.

Host: Thank you so much, Dr. Stevenson, for joining us today and really sharing your incredible expertise for other providers. And to refer your patient to Dr. Stevenson at Penn Medicine, you can call our 24/7 [00:11:00] provider-only line at 877-937-PENN. Or you can submit your referral via our secure online referral forum by visiting our website at pennmedicine.org/refer. I'm Melanie Cole. Thank you so much for joining us today.