Hi, this is Dr. Josh Husted and this is a presentation on surgical knee denervation. I'm an orthopedically trained hand upper extremity and peripheral nerve surgeon at the University of Arizona in Phoenix. I have a very unique practice in that when I started, I started practicing general orthopedic surgery and I saw patients with knee pain, but I also have specific training in peripheral nerve surgery and that's what led me to get involved in surgical knee denervation. I realize most of you have never even heard of surgical knee denervation, so I thought it would be good to start with a little bit of background information. When we've traditionally treated knee pain as orthopedic surgeons, we either tried to treat the inflammation with things that reduce inflammation like anti-inflammatory medications or cortisone injections, or we've just done a knee replacement. However, there's a growing need for alternatives to knee replacement, both in patients who can't get a total knee and patients who have a total knee and still have residual pain. A denervation procedure is a procedure that focuses on the nerves instead of replacing the joint or trying to seek to reduce the inflammation. Denervation procedure targets the nerves and interrupts the signal between the joint and the brain. It doesn't change the fact that the patient has arthritis, but it makes it so the patient can't feel it anymore. And we'll get into a little bit later in the presentation how we came about this technique and the current techniques that have been shown to work best. Currently, the American Academy of Orthopedic Surgeons only recommends activity modification, anti-inflammatories, cortisone, and knee replacement for knee osteoarthritis. It's interesting, there used to be recommendation for gel injections. That is no longer recommended, and the recommendation for cortisone injection has been downgraded. So essentially, you have the opportunity to treat patients with a cortisone injection or a total knee replacement. And obviously, there's a large gap in between those two, and therefore, people are seeking alternatives to try to bridge that gap between a cortisone injection and a total knee replacement. I got involved in this research when I was practicing general orthopedic surgery and had a lot of patients who came to me and said, hey, doctor, I'm just too old for a total knee replacement. Isn't there an alternative? And at the time, I was practicing general orthopedic surgery, scoping knees, but not doing knee replacements. And so I started looking for alternatives. Interestingly enough, I found in our highest level of evidence in the JBJS journal, an interesting article out of Harvard looking at cooled radiofrequency ablation compared to single injection of hyaluronic acid. This article didn't get a lot of press because we no longer recommend hyaluronic acid injections, although there are other randomized trials comparing cooled radiofrequency ablation of the nerves in comparison to cortisone injection. This really caught my eye. I also came across another company called Iovera, which has raised a lot of venture capital to support the idea of utilizing a nerve freezing agent in order to reduce the amount of pain that's transmitted along the geniculate nerves to the brain. Because of all these alternatives, I began looking at the possibility of doing a surgical denervation trial to see if we could come up with additional treatment options. Interestingly, all of the trials looking at treatment of knee pain due to nerves targeted the four geniculate nerves, the superior lateral, superior medial geniculate nerve, and the inferior medial and inferior lateral geniculate nerve. There are three treatment options that have arisen, which include radiofrequency ablation. Radiofrequency ablation is done through a needle through the skin, puts the nerve to sleep. Cryotherapy or cryoablation, which utilizes a freezing agent in order to freeze the nerve to go to sleep, or geniculate artery embolization, which is done by the interventional radiologist. All of these have been shown to be very beneficial. However, they're only temporary. All of the treatment options last only about six to 12 months. During the time that I was learning about all of these treatment options, I also met Dr. Lee Dellin, who is an expert in peripheral nerve surgery. He's written a wonderful book called Joint Denervation, and he described to me the history of surgical knee denervation. Because of his experience, I thought it would be very interesting to look into the option of doing something similar to what was being recommended by the pain management doctors and the interventional radiologists, but with the potential to make it a more permanent solution than something that would last six to 12 months. At the same time, I also got involved in targeted muscle reinnervation for lower extremity amputees. For those who aren't familiar with that, what that is, is when you make an amputation, you cut a major peripheral nerve, like the sciatic nerve. Instead of just cutting it and allowing it to stay or retract into muscle, that nerve will continue to try to find another nerve ending. As it reaches out to try to find that other nerve ending, it will form a neuroma, which will cause pain and will also likely be associated with phantom limb pain. Because of this, there's been described technique to cut the nerve, find a motor nerve that is going to muscle, cut that motor nerve to the muscle, and then innervate or reinnervate that muscle by sewing the two nerves together. This has been shown to significantly reduce the amount of phantom limb pain and neuroma pain associated with the amputations. Because I had gotten into targeted muscle reinnervation and because I'd met Dr. Lee Dellin, I wondered if we might be able to combine the two techniques and be able to come up with a permanent nerve transfer around the knee that may benefit the patient with long-term pain relief. I went to the lab and I designed a study where we would identify the superior lateral and superior medial geniculate nerves. We would transect those nerves and then find motor nerves that are going to the vastus lateralis and vastus medialis of the knee and plug those nerves into the muscle. The thought process behind this is that once those nerves are transected, they will then be plugged into the muscle and grow into the muscle. What was once then a sensory nerve will grow in and become a motor nerve. This will cause a cortical response change in the brain and interrupt the pain signal between the joint and the brain, leading to permanent and long-term pain relief. After conducting research in the cadaver lab, I elected to proceed with doing this in human patients. We received permission from the University of Arizona Institutional Review Board to do an investigational research study in humans. I didn't want to go out and sell a procedure that I didn't believe in, so we decided to do this procedure in 25 patients and follow them for two years. This is a picture from one of our patients. All of these patients were non-arthroplasty candidates, meaning they had presented to the Department of Orthopedics at the University of Arizona in Phoenix and were told that they were not candidates for arthroplasty and that they had no other options other than chronic pain medication. We initially did this through an open surgical approach. You can see in the picture on the left, there's a picture with the geniculate nerve running with the geniculate artery. We elevate and isolate those nerves. The middle picture shows me elevating and isolating a nerve off of the knee capsule. And then the picture on the right shows a vastus muscle cuff. There is a motor nerve that runs into the muscle, which goes on the inside of the muscle itself. We then take that nerve and coapt it to the nerve going to the muscle and wrap the muscle around it. We recently published our results from this clinical trial. At two years average follow-up in plastic and reconstructive surgery in July 2024, we're able to show a significant reduction in pain, improvement in function, and improvement in overall quality of life with a reduction of VAS pain scores of 8.8 to 2.9, an improvement in WOMAC scores, which is a functional outcome from 69 to 32, meaning they got better, and an improvement in quality of life score, EQ5D, from 0.18 to 0.65, showing an increase in overall quality of life. All of these were meeting minimally clinically important difference ratios and represented a significant and sustained improvement in quality of life and reduction in pain. Of most importance, these were patients who were told they had no other option, and their only other option was chronic pain medication. We were able to see at two years a reduction from 8.8 to 2.9. We also wanted to make sure that we saw a long-term pain reduction. If we only saw a transient reduction in pain, then it might be better to not undergo the risk of the surgery and just undergo a radiofrequency ablation. However, this seems to be sustained and long-term, if not permanent, leading to the long-term benefit of undergoing the surgical procedure instead of undergoing one of the temporary procedures described before. While we've been really happy with the open surgical denervation and the overall outcomes that we've had, it is a rather large incision, and these are patients often that are at risk for other things. They either have significant obesity, they have high hemoglobin A1Cs, or they have other comorbidities. We did have some patients who had some issues post-operatively with wound complications because of the large incisions. Because of that, we have developed an arthroscopic-assisted approach where the procedure can be done open initially with the nerve transfer into the muscle through a small 3-centimeter incision on either side of the leg, and the remaining portion of the inferior portion of the denervation is done with an arthroscopic-assisted approach, which allows for only a small poke hole and a 3-centimeter incision. This has significantly reduced the amount of wound complications and significantly improved the post-operative recovery in our patients. So who's a really good candidate for this type of procedure? We're really targeting what we would call those who don't fall into the normal bucket, so non-arthroplasty candidates are excellent candidates for this. High hemoglobin A1C, high obesity greater than 40 with BMIs above 40, and advanced comorbidities. Patients who don't fall into the normal age range, either they're too young or they're too old, and probably the most important is post-arthroplasty patients who still have knee pain. About, as we talked about before, about 20% of patients still have pain after a procedure like this, and they can be really great candidates for a knee denervation procedure. If you're interested in learning more about knee denervation or joint denervation in general, I founded the Joint Denervation Consortium. We have a website, www.jointdenervation.org. On this website, we have surgical technique videos for surgeons. We have information for medical professionals. This isn't just knee denervation. We have this for hand and wrist denervation, particularly CMC denervation where we've done a lot of research, and for knee denervation where we've done a lot of research. You can also give this to your patients that can provide additional information for them, and most importantly, there's a lot of patient stories and patient testimonials that you can share with patients and people in your community. It's been a pleasure to give you a rundown of what we've been able to do so far. This is a field, I think, that will absolutely change the way we think about pain and absolutely change the way we think about knee pain and knee treatment in the United States as well as around the world. If you have any questions, feel free to reach out to me. I have my cell phone and my email listed here. You can find out more at our website, www.jointdenervation.org, or my personal website, joshuacustedmd.com. Hello, my name is Michiel Zuytem. I'm a plastic surgeon of Rotterdam, the Netherlands, and I'd like to thank Sammy for the invitation to present on denervation of the wrist. I have nothing to disclose, and it was already in 1863 that Hilton described his law, hereby saying that every nerve which crosses a joint innervates this specific joint, and hereby he set sort of the surgical rules. When you're performing a denervation of a joint, you have to follow and check every nerve which crosses this joint. It wasn't until 1933 that a Swedish surgeon named Kamitz was the first to describe a denervation of the joint. He described a denervation of a hip joint by taking out or taking down branches of the obturator nerve. In 1958, so already 30 years later or 25 years later actually, Wilhelm, a German surgeon, first described a denervation of the wrist. He described meticulously the anatomy of the innervation of the wrist, and here you see one of his drawings. When you look closer to the anatomy, the images by Wilhelm are actually very detailed. He described from every nerve crossing the wrist capsule, these precise branches running off it, and all the side branches. This is a little bit too much detail, but it's a really nice image, and that's why in our PRS paper of 2021, we sort of simplified his technical drawings. It's still the same drawing, but we just made them a little bit more easier and gave you less detail. And here you see the dorsal side of the wrist. You see in the middle center the posterior interosseous nerve, which innervates the largest part of the dorsal capsule. You see on the radial side the radial sensory nerve, which innervates the radial dorsal side. You see the dorsal branch of the ulnar nerve, which innervates the dorsal ulnar side, and you also see the deep motor branch or the deep branch of the ulnar nerve on the other side of the wrist, of course, and you see that this deep motor branch gives off minor branches to the carpal, metacarpal joints, thereby also innervating the most distal part of the joint. On the volar side, there are a little bit more branches crossing the volar wrist. In the central part, you see the anterior interosseous nerve, which innervates the largest part of the volar capsule. You see the palmar cutaneous branch of the median nerve running off the median nerve about eight centimeters proximal to the wrist crease, also directly innervating the volar radial capsule. You see the lateral antebrachial cutaneous nerve, which innervates also the volar aspect of the wrist capsule directly. You see also there are sort of interconnections between the palmar cutaneous and the lateral antebrachial cutaneous nerve running onto and right next to the radial artery and the tendon sheet of the flexor carpi radialis. These are actually called Cruvalier's branches or Cruvalier's nerve, and they can give off minor branches to the volar radial capsule as well. You also see the ulnar nerve. We took out the median nerve, and you see that the median nerve and the ulnar nerve itself do not give branches to the volar wrist capsule. So they still comply to the Hilton's law, but they don't give off branches themselves. They give off branches to the volar capsule by the side branches like the AIN or the palmar cutaneous or for the ulnar nerve, the dorsal branch. Of course, what are the indications for wrist innervation? Of course, chronic, painful, radiocarpal or ulnar carpal wrist condition. Of course, conservative management has to fail or at least does not give a sufficient pain reduction. The innervation can be performed as a standalone procedure or it can be combined. They're not really any contraindication, but of course, if there are correctable conditions, you should definitely try to correct them. Like in the case of a scaphoid nonunion, you want to repair the nonunion to prevent osteoarthritis rather than only performing a wrist innervation. The indications for a degenerative wrist already been described by Kurt Watson several years ago. Slack wrist. Here you see the pattern of the slack wrist, the snack wrist, the scaphoid nonunion advanced collapse. They're all pretty good indications for a wrist innervation. So what about the surgical procedure? In his 2001 paper, Wilhelm nicely described his technique and his technique was a total wrist denervation. He described a sort of five incisions approach and he wanted to take down all these branches, all these detailed articular branches, which he described in his previous articles or manuscript. That's why he performed so many incisions. He wants to attack all of them. But actually in 1998, Berger already described a sort of partial denervation, not going at all these minor branches, but just going at two of them, the posterior interosseous nerve and the anterior interosseous nerve. And he described the same results. Here you see a cross-sectional image from his paper, where you see that the posterior interosseous nerve is right onto the interosseous membrane. And on the folar side of this interosseous membrane is the anterior interosseous nerve. So in more detail, the surgical procedure of a partial wrist denervation, it's under local anesthesia or general, but it can be performed on the local anesthesia with or without tourniquet, whatever you prefer. You take a longitudinal incision proximal to the distal radial ulnar joint. You open up the fourth extensor compartment and in the bottom of the fourth extensor compartment, you'll find the posterior interosseous nerve right next to the posterior interosseous artery. You don't have to take down the posterior interosseous artery, of course, but sometimes it can be difficult to divide them properly. And then you take them both out. I'd like to take out at least a centimeter or a centimeter or a half of the posterior interosseous nerve and not giving them any chance of reconnecting while recovering. After you've taken down the posterior interosseous nerve, you open up the interosseous membrane. And when you open up the interosseous membrane, you directly fall onto the pronator quadratus muscle or onto the AIN, the anterior interosseous nerve. You also encounter the anterior interosseous artery, of course, you can take them both down. You can take a part of the pronator quadratus muscle out if you need to. That's not really a problem, but of course you'll be denervating the pronator quadratus muscle. Here again, take out a small piece. Do a proper hemostasis because you've been in an area of these both arteries and then close up with anything you like. Put on a small bandage and let them move around as quickly as possible. So what about results? Professor Wilhelm himself already described in 2001, his sort of 195 cases where he had a almost 80% success rate in pain reduction. Excellent or good results in 80% of the people. And in our paper of 2021 in the PRS, we sort of did sort of, we made a match analysis of all the results which are out there in literature for a total and partial wrist denervation. And we made them into a force plot. And here you see the results. And in more detail, you see that 83% of the people have a pain reduction, regardless if you do a total or a partial denervation. So a partial denervation is just as good, at least in these results as a total denervation. So what about propriocepsis? You're going to take down the propriocepsis of the wrist. Firstly, complications, only minor complications, but the loss of propriocepsis can be a problem. And some say it's not a problem at all. Some say it doesn't really matter, but some say it does. And I think it's still debatable if it is. For me, it's not really a problem, but some people say it's a larger problem. That's why they don't perform a denervation as a standalone procedure. So thank you for the opportunity to present, and I'll hand the word back to the chairman. Thanks. I'm going to talk next about thumb CMC denervation for painful arthritis. Here are my disclosures. Thumb CMC arthritis is a common cause of pain, weakness, and disability. When conservative measures fail, surgery becomes indicated, and the traditional, most commonly performed approaches involve resection of the painful arthritic joint with a trapeziectomy, which can be performed alone, but is often combined with a suspensionplasty or less commonly with synthetic arthroplasty. And all of these procedures are effective in terms of achieving pain relief, which is the primary goal of any surgery for thumb CMC arthritis. But they come at the expense of a long, painful recovery course and the need for prolonged immobilization. And these surgeries also carry risks that are not insignificant, including the possibility of tendon rupture, subsidence, and weakness. Also, when these surgeries do fail, it's hard to know what to do next. The published outcomes with revision surgery for CMC arthritis are less than favorable. So this raises the question of whether joint denervation can be effectively employed for this problem. Joint denervation has been more extensively used for wrist, elbow, and knee arthritis. There were a few case series published as early as 1998 by Foucher, but for whatever reason, they never really gained much traction, and these procedures never really caught on until more recently. So Dr. Lifshay, Scott Lifshay at Johns Hopkins and colleagues published a preliminary case series about five years ago, which kind of reinvigorated interest in this procedure. And this initial case series included a cadaveric study where the nerves supplying articular branches to the thumb CMC joint were studied in the cadaver lab. And these nerves were found to include the lateral antebrachial cutaneous nerve, the palmar cutaneous branch of the median nerve and the radial sensory nerve. Keep in mind that it doesn't really matter where these articular branches are coming from. You just need to know where they terminate, how to find them, and then address them. So the surgical approach that Dr. Lifshay employed in his case series involves a Wagner incision, first moving dorsally, raising the dorsal skin flap, bringing up the radial sensory nerve and its branches with it. And when you create that dorsal dissection plane, you're looking for articular branches traversing perpendicular across your dissection plane and terminating in the joint. Then you move more proximally to the anatomic snuff box, looking for the termination of the lateral antebrachial cutaneous nerve into the joint. And this nerve will typically travel with the radial vessels. And so what I like to do is actually dissect out the radial vessels, fully mobilize them, often using a vessel loop. And this allows for easy identification of the lateral antebrachial cutaneous nerve. Just by manipulating the whole bundle, you'll see the nerve terminating into the joint, and then you can divide it. And finally, you move volarly, lifting off the origin of the thenar muscles from the volar joint capsule. And you'll find typically one to two terminal nerve branches that have traversed through the muscle and terminated in the joint, either arising from the palmar cutaneous branch of the median nerve, or perhaps from the recurrent thenar motor nerve. An important point to avoid the complication of painful neuroma is that you really wanna interrogate these articular branches before you cut them and make sure that they truly are articulating in the joint capsule and not continuing on to supply the skin. You can see me doing that here. Again, here with a large LAPC branch. So in the initial case series from Lifshay and colleagues, the included 10 females and three males with an average followup of 16 months. And 12 of the 13 patients had complete or near complete resolution of their pain. One of the patients actually came back for a contralateral denervation, which is a good indicator that the patient was satisfied with the first procedure. There was one failure in this initial case series where the patient went on to an LRTI at 17 months post-op. And you can see that there was measurable improvement in grip strength and lateral key pinch strength, minimal complications. Pretty much all of these patients, if you ask them, will endorse some peri-incisional patchy numbness, but it doesn't seem to bother them. And they often won't mention it unless you ask. There was one patient in Lifshay's initial series who he thought had a radio-sensitive neuroma, but this resolved fully with a single steroid injection. So it's hard to say what the actual cause of that pain was. This is the main benefit of this procedure in comparison to trapeziactomy. The very easy post-operative course with one to two weeks in a soft dressing, sutures are at the first appointment and then rapid return to normal activities. So Dr. Lifshay more recently published a follow-up study, including his initial cohort plus additional patients, and compared this to a matched cohort of patients undergoing LRTI. Both patients had significant improvements in pain and there were no statistically significant differences between the groups. There were three patients in the denervation group who ultimately underwent secondary surgeries. And there was a small number of patients who had initial improvement in symptoms and then subsequent recurrence in the years that followed. So this is worth noting when you counsel your patients that perhaps there is a higher recurrence rate with a denervation as opposed to an LRTI, and this is still an open question. More recently, Josh Husted, who's one of our panelists here, published a great study prospectively evaluating denervations and comparing them to trapeziectomy and suspension plasty. And again, both groups have significant improvement in pain with no differences noted between groups and the outcome measures. And again, importantly, highlighting the most obvious benefit of denervations, he found that the patients who had denervation had returned to function in 3.3 weeks in comparison to 4.5 months with the suspension plasty. So the take-home points here are that dumb CMC denervation does appear to be effective in treating pain, at least in the short to medium term. And there's still a question about the long-term durability and whether there's a higher recurrence rate in comparison to trapeziectomy procedures. I counsel my patients that the goal here is to get them at least a temporary relief in their symptoms, and that they may ultimately require a trapeziectomy in the future, but it would be more ideal to have that more invasive surgery performed when they're in their later years. And the main benefit of the thumb CMC denervation is the easier, faster recovery course post-operatively. And I think the ideal patients to first consider if you're wondering kind of, if you're considering dipping your toe in the water would be the patient with the failed trapeziectomy, the young high demand patient with good range of motion who you hesitate to offer a trapeziectomy to, and those patients who are hesitant to undergo surgery because of the arduous recovery course required for a trapeziectomy. So moving on quickly to cover the MP and the IP joints. I think that my favorite joint to denervate for arthritis is the PIP joint. The surgeries are very satisfying because you will consistently find substantial articular branches with reliable anatomy, and you leave the OR feeling like there's a really good chance that you addressed all of the potential articular branch sites because the joint is relatively small and you can get around it completely. And also importantly, the traditional options for addressing PIP joint innervation surgically are suboptimal at best, including fusion or arthroplasty, synthetic arthroplasty. So the anatomy of the articular branches to find the PIP joint are fairly consistent and reliable. There's always at least one branch arising from each of the proper digital nerves entering the PIP joint at the vulvar border of the vulvar plate or at the proximal border of the vulvar plate. Sometimes you'll find a more distal branch and there are also some more wispy contributions coming from the traversing branches from the dorsal sensory nerves. There are many different surgical approaches that have been described, including two mid laterals, a vulvar brunner or dorsal approach. I personally prefer using two mid laterals to access the PIP joint when I'm doing an isolated PIP joint innervation. When I'm doing a PIP joint plus DIP joint innervation, I'll use a dorsal incision, as you can see there below. And you can see that the branches arising from the proper digital nerves supplying the joint are quite robust. You can't miss them. And they will always be here coming in approximately and sometimes you'll find another one further distally. With regards to the DIP joint, I will rarely perform an isolated DIP joint innervation because I think the option of a fusion for a DIP joint arthritis is pretty good, especially because a lot of these patients have deformity that they want to have addressed in addition to their pain. But that's not to say that a DIP joint innervation in isolation has no role, but at least in my hands, I will typically only be performing this procedure in conjunction with a PIP joint innervation. And lastly, the MP joints are also amenable to the innervation, and this is also an effective, satisfying procedure. The common digital nerves will reliably send branches to the MP joint, as you can see right here. And then there are also robust marticular branches arising from the dorsal sensory branches, which you can see here and here. Also importantly, the deep ulnar motor nerve will send branches to the MP joints. And these can be harder to find and they can kind of sneak by you if you're not looking for them. So make sure to interrogate this when you're performing these procedures. And here's a summary of the reported data thus far. Still somewhat preliminary, but certainly promising. And this is consistent with my own anecdotal experience thus far. Thank you. ♪♪

knee denervation

pain relief

radiofrequency ablation

cryotherapy

geniculate nerves

arthroscopic-assisted

knee pain treatment