David Fabi, MD, Orthopedic Surgeon, Chief of Orthopedic Surgery Scripps Mercy Hospital as well as Joint Replacement Specialist talks about the knee replacement he performed on Sister Margaret Castro.
Interview conducted by Ivanhoe Broadcast News in February 2018.
Let’s talk about the Sister and what you did for her.
Dr. Fabi: Sister Margaret came to me in a lot of pain. She had a previous knee replacement on her other knee from one of my retired partners and one of the first things she wanted out of another knee replacement is that she wanted to kneel. She serves the community; she’s obviously a devout catholic, so that’s very important to her. So she tried everything besides surgery and she was ready for a knee replacement. Because she exhausted all conservative measures, she was a perfect candidate for knee replacement. And at that time I had started doing robotic knee replacement surgery. Beyond just doing a knee replacement like we normally do we have added steps using computers, robots to really customize a knee replacement that lends itself to improved accuracy and precision and ultimately excellent results with potentially a long lasting joint replacement. That’s what we did for Sister and she recovered pretty quickly from it.
How old was she when you did the surgery? Seventy seven?
Dr. Fabi: Seventy seven.
Is this typical of the age of your patients?
Dr. Fabi: The ages I treat comprise a wide spectrum. I’d say my demographic is anywhere from early fifties to late eighties. The average age is probably in the range of sixty to sixty five. She is a young seventy seven year old, but yes she is within the normal demographic of the patients that I take care of.
With the robotic part of it, what would be different or unique for her case?
Dr. Fabi: We’ve done countless studies with regards to what are the benefits of robotic or computer assisted technology as it relates to knee replacement. Standard instrumentation is pretty well designed with the instruments that we use, but even with that we’re about anywhere from seventy five to ninety percent accurate because there’s human error involved. No matter what we’re humans; we’re not infallible and we are hitting about a ninety percent target rate at best. What the robotic technology and computer technology provides is that now we’re able to achieve ninety eight to ninety nine percent accuracy. Which is important because a knee replacement is a game of millimeters; it’s a game of degrees and if you’re off by a millimeter or off by a degree, that can lead to a sub-optimal result or not a result we’re looking for.
it’s placement it’s not necessarily usage?
Dr. Fabi: Yes.
That the robot is helping you with?
Dr. Fabi: It does a variety of things. Most importantly: placement. What it allows us to do is essentially customize the knee replacement to that patient’s specific knee, to their specific anatomy. We trace out their knee during the operation and the software formulates a 3-D virtual model that’s presented on the screen and virtually we’re able to fit the implants to their anatomy and also designate specific parameters as to how we want to do that knee replacement. That’s just one part of it. There is an art to knee replacement. It’s not just cutting bone and putting in implants; you’ve got to deal with ligament tightness and ligament looseness. We’ve got to do certain procedures as how we handle the ligaments whether we release them or tighten them to make sure the knee comes out as a balanced knee. Meaning: the pressures are equal throughout the knee so that it moves more like a normal knee. And this technology provides that information which is information we never had before. Usually this art aspect that I talk about was very subjective in nature. Now we have hard core objective data, numbers, and graphs to tell us and validate how well we are doing with this part of the procedure.
Would the way you put in the knees and tighten the ligaments be different for Sister than for someone who is maybe still at fifty and a competitive athlete?
Dr. Fabi: Absolutely. Everybody that comes in for a knee replacement has what we call a soft tissue character to the knee replacement, it’s almost like their knee has its own fingerprint. We want to match that fingerprint and all these programs allow us to do that.
I know you are traveling the world; tell me a little bit about how this technology is spreading right now.
Dr. Fabi: The buzz is out there, people are getting really excited not just here in the United States, not just in San Diego at Scripps Mercy Hospital, but worldwide. I travel to India, I travel to Singapore, to teach and next moth I’m traveling to Dubai and going back to Singapore to train other surgeons. Surgeons in India are super excited about it and they have the robotic technology over there. People are getting behind it. And now Australia, South Africa are instituting this technology.
You said you traced the knee during surgery so is there pre-work or is it all done through the surgery part?
Dr. Fabi: That’s a very good question. This robotic system doesn’t require any preoperative work whereas other systems will require a preoperative CAT scan or even a preoperative MRI to help plan for the surgery. That’s one of the advantages of this technology that you don’t need that.
Does it add much time to the surgery then?
Dr. Fabi: We always want to get to what we call time neutral. Meaning the length the surgery will equal what we do with standard instrumentation. A knee replacement can be done anywhere from forty to sixty minutes. With this technology, yes it’s added steps. I’ve probably whittled it down to maybe five to ten minutes longer than what my normal knee replacement would be. My normal knee replacement would take me anywhere from forty five, fifty five minutes. This is a little longer but what I tell other surgeons is that my ten minutes in that OR room is nothing compared to the next twenty five years, thirty years of that patient’s life with their knee replacement. I’m not going to be that selfish just so I can get home earlier or I can add on another case.
When you’re measuring success the ninety compared to ninety eight percent with robotic what is that, is that flexion?
Dr. Fabi: That’s a very good question. When I put out those numbers, we’re talking about what we call a mechanical axis. Essentially alignment of the patient’s leg. We start from the center of the hip to the center of the knee to the center of ankle and you want that to be a straight line. You want the pressure going straight through the middle of the knee implant. We consider normal anywhere from zero to three degrees. If you’re going beyond that you’re putting pressures on the knee implant where the implant can’t take that. They can only take it for a certain amount of time. When I’m talking about ninety nine, ninety eight, ninety nine percent accuracy we’re hitting within in zero to three degrees.
What haven’t I asked you about Sister’s case or about the procedure in general that think should be out there?
Dr. Fabi: I think this is just the tip of the iceberg for this technology; it continues to expand. Now currently me and a few surgeons in the country are starting to utilize this for ACL sparing knee replacements. Meaning most of the time most knee replacements either you’ve got to cut the anterior cruciate ligament which is one of the ligaments in your knees as well as plus or minus the posterior cruciate ligament. This technology, this new implant saves both the anterior cruciate ligament ACL and the posterior crucial ligament and the PCL. We want the patient to achieve what we call the forgotten knee. Meaning they don’t notice that it’s a knee replacement anymore. Potentially by saving the ACL we can achieve that and increase their satisfaction, make the knee replacement more functional. This technology has expanded to this and I think using the NAVIO blue belt system and doing ACL sparing knee is a perfect marriage of these two technologies. We’re really excited about this; it’s going to continue to expand in the total hip replacement realm. Also with regards to joint replacement, they don’t last forever, some of them do fail. We see value of this technology utilizing it when you have to redo hip and knee replacements.
You won’t have to take it out and start all over, you can just do a realign?
Dr. Fabi: Potentially, that’s an option. But when we’ve got to take out implants invariably there’s some element of bone loss. What we have to do is we need to manage that bone loss. Either replace it with metal, with bone graft, etc. Using this robotic technology that has robotic tools we can manage that bone loss more accurately with better fixation.
Is it just giving you information or is it actually doing some of the procedure?
Dr. Fabi: That’s another good question. A lot of patients come in to me they’re like, well are you going to be doing the surgery? I’m not going to be sitting in the other room watching a robot doing surgery while I’m drinking coffee. I say ninety five percent of the surgery is still the same. I’m doing surgery and all I have is this robotic tool within my hands to help me do added stuff and prepare the bone safely to give you a homerun knee replacement.
Talk about recovery.
Dr. Fabi: I started doing this in August 2016 and to date I’ve done probably over two hundred fifty. The company tells me that’s the most in the world for this specific robotic technology. And it’s probably competitive with our other big competitor. When I counsel a patient on this technology they get really excited about it. In terms of how it improves their recovery, I’m doing all I can to give that patient the best result possible. I know what the patient’s alignment after the surgery is; I know that I did the art of knee replacement to the best of my ability. After that things are out of my control but I mentioned before it’s a game of degrees, a game of millimeters. If you’re spot on that patient is going to do well. I’ve seen patient’s recovery as early as two weeks. Now that’s the minority that’s not the majority. But I always counsel my patients the brunt of your recovery will be within the two to six weeks’ time frame. Some people take longer we’re just talking averages and that’s okay. But it’s not a four to six month deal like it used to be. We’re starting to really match our recovery to what we see in hip replacement.
END OF INTERVIEW
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