Section: CME Category: Surgery

Hemi Implant Great Toe Joint

Harold Schoenhaus, DPM

Harold Schoenhaus, DPM reviews the etiology of hallux rigidus as well as describing the role of the sesamoids apparatus. Dr Schoenhaus also explains the surgical approach to hemi-implantation for the treatment of hallux rigidus.

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Goals and Objectives
  1. Review the etiology of hallux rigidus
  2. Describe the role of sesamoids in hallux rigidus
  3. Explain the surgical approach to implantation
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    Release Date: 10/15/2018 Expiration Date: 12/31/2020

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  • Lecture Transcript
  • TAPE STARTS – [00:00]


    Unidentified Male Speaker: Alright. I thought I would share some thoughts with you on hemi implantation of the great toe joint. It's certainly have been controversial over the years as to should you use an implant in the great toe joint to provide better motion or do you fuse the great toe joint in advanced degenerative joint disease? And I've always been an advocate of the concept of motion is life. You saw that on my other presentation. Big toe joint is probably the most important joint in the front of the foot. The big toe is what I refer to as our propulsive organ in the front.

    You're pushing off with that guy. It's there for a reason. If I can maintain motion in that joint I've always tried to do that. Now certainly, there are exceptions to that and there are times when I will fuse a great toe joint and I would tell you that patients do well with the fusion. Some restrictions and limitations, especially with women, with the need to where heels and how high of a heel they want to wear. You're not going to be able to accomplish that so easily with a fusion. Now, it's not to say that you're going to wear a four or five-inch heel with a hemi implant or an implant in the great toe joint.

    I'm not going to tell you that either. But let's take a look at some of the concepts and thoughts that I've experienced through the years because I've been doing implant to the great toe joint by just as long as I've been in practice. Learning objectives, what's the ideology of hallux rigidus? Understanding the role of the sesamoids in hallux rigidus, which is often neglected in the thought process and then identify the surgical approach to implantation.

    [02:04]

    So what's the criteria indications for implant for hallux rigidus? First of all, definition, what is hallux rigidus? It kind of implies that there's an advance stage of degenerative disease, which destroys the joint. Now, you may see more destruction on the head of the first metatarsal versus the base, but in essence, we are losing the important tissue within the joint, which is hyaline cartilage, which is then lubricated by the synovial lining. Now, you've got a frictionless, almost frictionless environment to allow for motion to take place in this very important joint.

    So when we look at ideology of hallux rigidus, we think of degenerative joint disease. You certainly can have osteoarthritis of the great toe joint. You can have it secondary to trauma. Something could drop on the joint or you kick something, and years later, things start to change within the joint confines. So you have pain with activity. Your range of motion is markedly diminished. The size of the joint actually gets much bigger, the construct of around the first MPJ.

    Age predominantly greater than 50 years and an expectation if you're going to try to use implant is mild to moderate activity post-operatively. So you look at the x-ray and you see a squaring of the joint, you see narrowing of the joint space. That obviously is indicative to you that the cartilage is gone, it's shut and there will degrees of that as you go from the stage of hallux limitus to ultimately hallux rigidus.

    [04:02]

    I always look at hallux limitus as limited motion in the joint more times than not associated with an elevated first metatarsal in the propulsive phase or if it's post-traumatic, it's early stage limitation of motion, which will lead to full-blown degenerative joint disease. There may be an element of elevatus and you could see it on this x-ray where the first metatarsal is actually above the level of the second. When you look from proximal to distal, we're getting higher. We have this hook on the dorsal aspect of the metatarsal head.

    You don't always have it of that size. Some are bigger. Some are smaller. Many physicians go in and say, "Well, the problem of this joint is that big spur on top. Let's just knock it off and do a cheilectomy," which does really nothing other than de-bulk the top, but doesn't do anything for the underlying disease process. When you look at the great toe joint, there are three primary components to it in my mind. One, the base of the proximal phalanx, two, the head of the first metatarsal and three, the sesamoid apparatus, and if you don't approach or appreciate what the sesamoid apparatus is doing, you're going to have poor results no matter what you're trying to do, except the fusion possibly.

    We recognize that the sesamoids are actually encased in the belly of the flexor hallucis brevis, the medial sesamoid is conjoined with the abductor hallucis, the lateral sesamoid with the adductor hallucis. They then proceed forward as a membrane, a member's expansion from the sesamoids to the base of the proximal phalanx and in on to the shaft somewhat plantarly.

    [06:04]

    There is a joint that exists between the sesamoids and the head of the first metatarsal inferiorly. There's an active joint with hyaline cartilage available. When you go into the propulsive phase of gait in a normal patient, you're actually rolling up on to the sesamoid apparatus. That's why the first metatarsal is always got to be shorter than the second to enable you to come up. That's where you're obtaining your 65% of dorsiflexion because the first ray is pushed back somewhat by the intrinsic muscles and then you glide on to the head of the – on to the proximal phalanx. So the sesamoid first metatarsal relationship is critically important. You need motion at that site. So now, we take that in consideration in the disease process or entity.

    Here is a great example of elevatus of the first ray. Now, what causes elevatus? It could be post-traumatic that you've injured the proximal portion of the first metatarsal in a sports injury as a youngster, and the epiphyseal plate has been injured or the more common thing we see it is associated with hyper mobility of the first ray. And these don't even have to be in severe flat feet by the way. In the compensated rearfoot varus foot, tibia varum, genu varum, rearfoot varum, the compensation for that deformity only requires the calcaneus to go to perpendicular. So these people often maintain an arch, but when you look distally you begin to realize the metatarsal is elevated.

    [08:01]

    Is it structural, is it functional? If that patient that you see here has a structural elevatus, there's no way the great toe can dorsiflex on to the metatarsal and the metatarsals cannot rotate on to the sesamoid apparatus. So if you were just addressing, maybe there's dorsal prominence if you think there is one here. If you wish to have dorsiflexion occurring at this joint, you've got to drop the first ray. You got to do an osteotomy of the first metatarsal to bring it down if it's structural. What if it's functional? What's the difference?

    Functional means that if I stop the hyperpronation syndrome, engage the activity, the peroneus longus, we can see the first ray coming down overtime. Now, how do you diagnose structural versus functional? Because in the propulsive phase, this is going to be a critical factor in what you're going to be doing and I'll show you this in a minute. What are the goals of surgery? Alleviate pain, improve range of motion, improve the quality of motion and reduce deformity. That's my goal in surgery for implantation of the great toe joint. I don't tell my patient I'm going to give you a new joint.

    Giving you a new part to the joint, but I'm not giving you a new joint that they think it's going to be like brand new, ball and socket type of function just like when I was six or eight years old. That's not going to happen. Don't expect that goal. It's a misleading one. You heard that pretty much this morning in the medical legal talk. Be careful what you identify and what you're telling patients and be sure you put it into the chart so that everybody is on the same page.

    [10:06]

    Misconception, you're going to have normal motion post-op, no. You're going to have improved motion. Able to wear shoes with a heel height greater than two inches, I don't tell them that. Up to an inch and a half and it's going to be as good as new. Those are terms that will get you into trouble all the time, and that's what they'll remember. Complications, poor range of motion post-operatively. Painful range, lesser metatarsalgia, lack of hallux purchase, implant bulldozing and implant stem plantar flexion and here is an example of that in how you actually put a stem – oops, sorry about that, into the base of the proximal phalanx, you could see here that it's pointed down and I'll talk about that in a minute.

    So most of these complications by the way are reactogenic, that's right, we're causing them. There're a number of hemi implants that I like to use. I've used this one that you see here, which is titanium and then there's another implant that's cobalt-chrome. I mean you have one of the exhibitors out here, BioPro will show you that implant if you're so interested in it. My incision, curvilinear over the great toe joint, I do not like straight incisions over the great toe joint. Scars contract along their long access. I don't want to see a big toe being pulled up because of scar contraction. So it's a little bit of an S-shaped curve, minimal dissection.

    [11:59]

    I do not believe in taking soft tissues and going through different planes and retracting and retracting, no. I'm going right down to where the nitty-gritty is and I make a longitudinal cut right over the joint, identify the diseased portion of hypertrophic bone, make a determination if the base is involved primarily or the head of the metatarsal. And you denude all of the junk bone. It's a cheilectomy you're performing on the table to get a better look at the anatomy of what's taking place. If you're going to do a cheilectomy, one of the procedures could be done along with it is a modified stone or a hemi Valenti where you're actually taking off more of the dorsal portion. I never liked that procedure because you're leaving exposed bone and if you have cartilage on the base of the proximal phalanx, it's going to chew it up overtime.

    So initially, it may look better or feel better, long-term, no good. So when you using a hemi implant, the first thing I do is try to make that head spherical as possible, get rid of all the ectopic bone and then I'm going to resect a portion of the base of the phalanx. Now, what's critically important in hemi implantation is you are decompressing the joint. So I have to take out a little bit more bone than what I'm going to replace it with, which is the implant. The flexor mechanism on the bottom has not allowed for dorsiflexion or hasn't been involved with dorsiflexion for years. What happens to muscle tendon complex if you don't stretch it? It contracts. So we have to release some of that. That's the decompression component by doing a hemi implant.

    [13:59]

    I also angulate to cut a little bit so that I am going to be able to go straight down the central part of the canal on the proximal phalangeal base. I would also tell you, if you're using power equipment, don't cut the entire base off with the power equipment. Go down three quarters, seven eighths through, leave the little plantar cortex, take a little chisel, mallet and just finish the complete cut. I do not want to risk cutting the intrinsic muscles on the bottom. If you cut the intrinsic musculature going to the base, you will end up with a pollux and apropulsive hallux in a patient that's not a happy camper. And I never liked trying to resaw that into the base. There's nothing as strong as the attachment of the original insertion, maintain it.

    If you look down into that surgical site and see the long flexor tendon, you blew it. So when I'm doing this with residents, I do it with a bit of trepidation and I tell them, alright, take the saw, careful on what you're cutting, easy, easy, okay, stop and then we complete the procedure. So as you look into this wound now, this resected area, you see the membrane and its expansion, which is the flexor apparatus going from the sesamoids to the base of the proximal phalanx. Now, I've got my space. Now, the head depending upon how bad it is, you will determine what you may want to do because most of the disease quite frankly is seen on the head. The base, not so much, but metal against denuded cartilage and even some bone functions very nicely.

    [16:03]

    You don't get this detritic synovitis that we used to see with silicon. So the metals have stood the test of time in the great toe joint. If you have spotty areas of cartilage degeneration on the head, drill it. Take a 20 drill bit and put multiple holes through there to try to encourage new cartilage to develop. Now, what typically is done, which my residents always say, "Alright, let's have the McGlamry Elevator." This is what I call the snow shovel and you put it under the first metatarsal and what are you using it for? To break up adhesions between the sesamoid and the head. Anybody in here ever done that? You just realized the sesamoid is not moving things, let's break that up and then you watch the range of motion increase and everybody is happy.

    Oh, great job, except you've just cut through a joint that has degenerative arthritis, the sesamoid first metatarsal apparatus and because you've freed it up you think that's given me great motion. It does at the time, but what's going to happen to that joint? You haven't replaced the cartilage. You haven't done anything for the sesamoid first metatarsal interface. Overtime, what happens to your range of motion? It starts to diminish because the sesamoids will once again attach to the first metatarsal. So here is techniques that you can use for just placing the implant into the base of the proximal phalanx. I try to be sure that I use an appropriate size both in width and height so that enough surface area is covered.

    [18:01]

    The entire cortical component of the base of the proximal phalanx needs to be covered by the implant, not the implant sitting internal to that because you could bulldoze overtime the implant directly into the base. Now, if you take a look at this you'll see something that looks like a little ribbon. Tie a yellow ribbon around the old oak tree. This is GRAFTJACKET, acellular dermis. Now, it's interesting you just heard a whole talk about the use of these materials for stem cells that help heal tissue. When I started using acellular dermis many years ago for tendon ligament repair, "I said wait a minute. Can I use this over the first metatarsal?" I am going to change the shape of the first metatarsal in addition to putting a hemi implant in.

    I'm turning it into a sphere. Not only am I going to take off all the disease cartilage, I'm getting through the subchondral plate, and now going to be looking at beautiful cancellous bone in the form of a sphere and I'm separating the sesamoid apparatus inferiorly. Because what I am about to do is actually cover the entire head of the first metatarsal distally both dorsally, plantarly, medially and laterally with acellular dermis. We now have a membrane sitting between the sesamoid and the inferior aspect of the head of the metatarsal. So I will not develop a sesamoiditis post-operatively. Now, when I first started doing this, some people thought well, that's nuts.

    [20:00]

    Does it make sense? We're not sure. We don't know what's going to happen with acellular dermis on bone. Now, since I did this and we wrote a number of articles about it, [Chris Hyra] [20:14] has written articles about it of resurfacing of the first metatarsal head using acellular dermis. Instrumentation is always a beautiful thing. It makes our life so much easier, sizes, determination of the implant. Shape, there's a thaw car stop type of shape, the other is more of a blade type of shape. And here we are with this acellular dermis and then there it is. If the sesamoids are fibrosed, they're not released from their contractions. Any procedure performed for the arthritic condition will not be successful. So let's just take a look at this.

    So here it is. Here is the acellular dermis. I resurfaced the entire head, I shape it, take off all ectopic bone. I then use one of the instruments for actually a nice ball and socket fusion technique and denude all the excessive cartilage and get through the subchondral plate. So take a look at the head now. You don't see a subchondral plate. There's no cartilage. We see nice cancellous bone and I'm going to place that implant or wrap around the head. It's almost – I hate to use the term, but it's almost like a prophylactic going over the head of the first metatarsal. It has to sit extremely snug and that's why I wrap it usually with fiber wire to hold it in place.

    [22:02]

    Here is the preparation for the base for an implant. Here is how I actually use or replace this acellular dermis around the head of the metatarsal. I use a tendon passer, using tendon passer with two drill holes from the top down and take a suture on the acellular dermis, pull it up through the holes. So now, I've got it back far enough behind the sesamoid apparatus between it and the head of the metatarsal. Then, I'm ready to flip it over the head. There we are drilling the holes with two little drill bits. Pick it up, so now I've got that sesamoid separation and now I'm ready to place to this membrane underneath the metatarsal head.

    There we are. It's pulled nice and tight and have my assistant's help in holding that piece plantarly, medially, laterally and dorsally. And then I begin to suture around the acellular dermis, right by the neck of the metatarsal. And then I remove all the excessive amount, I now have a new covered head. There's the base of a proximal phalanx that's been resected. I now have a hemi implant in place. And now we have a nice ball and socket joint that is going to allow for improved motion of the great toe joint gliding, sliding without crepitation. Other cases that I've performed this on, here is another case. This was a hemi implant that somebody had put in.

    [24:01]

    The head was still problematic. You could see that the length of that head is on the longer side versus the second metatarsal. Need to be shortened somewhat. I actually went in and remove the other implant. You could see what that joint looks like. You think that's ever going to move? It's almost vertical, can't get curvilinear motion when both sides are straight up and down. So I just went in and there's that magic shovel underneath the metatarsal, remodeled the head entirely. Resurfaced, and there we are.

    Now, the toe looks a little shorter, the patient knew that because I had to take off bone from the first metatarsal head. I actually put in another hemi implant, same as the one that she had in there, same manufacturer and it worked very well. So we went from there to there. I didn't change the direction of the implant. It wasn't necessary and the patient did nicely. Here is another example. Here is one that I actually used an external fixator to maintain the space. They could even move when you use an external fixator with a joint.

    It can actually allow dorsiflexion and plantar flexion in the early healing stages while maintain the separation. Here is an example of what we see by the way in acellular dermis. When you'd go back and look at histologically, when you put it over bone, you will actually see infiltration of cartilage cells. There they are. Scary, it's almost like the stem cells coming from the metatarsal head area and that's why you got to get through the subchondral plate, the bleeding through becomes involved with the acellular dermis and you get an infiltration and change into cartilage.

    [26:18]

    Now, this is my priced picture of the day for you. The first case I ever did, a patient was an executive, came up from South Carolina. Didn't want a fusion, heard that I put implants in. And I said, "Okay, this is the combination you need." Understood the entire procedure and about two years later she called me and she said, "You know, I have a little bump on the top of my big toe joint area and it bothers me with shoes. I want you to take it off." So she came up, I looked at her, she had a little something in the soft tissue. It looked like more of a suture than anything else and I said to her, "I'll tell you what I'm going to do.

    I don't think you really need it done, but if it bothering you that much I'll do it for you. However, you need to allow me to open up your big toe joint so I can look at what happened to the head of that metatarsal with the acellular dermis." So she said, "No problem, I'd love to let you do that. Go ahead." My residents as residents often can be were skeptic, they were laughing at me and they said, "Sure. Now, we'll see what happened to your acellular dermis." You are now looking at what happens to acellular dermis. Look at this. And it's cartilage on the head of the metatarsal. Back here, the sutures from the original pulling back and suturing over for the acellular dermis.

    [27:57]

    So here, we have a resurfacing of the head of the metatarsal using acellular dermis, maintaining the separation between the sesamoids and the metatarsal and I think that's pretty darn impressive. Of course, I just nod and chill out and I said to my residents, "Of course, I thought that would happen." And they said, "You're full of crap." But the bottom line was I had a good sense that there's a chance that something could happen because as I showed you the histologic pictures of GRAFTJACKET at the time over bone that they show that you could actually infiltrate with cartilage.

    So it's pretty impressive in my opinion and it's something that I do on a regular basis when that head is significantly destroyed and you tell me that's what a disease is and the sesamoids. Good, I've got the answer for you. And why do I do the base? Because I need to decompress the joint at the same time. I don't know what those are, but there again is the histology with the infiltration. So I've always said to my residents get your head out of your – think outside the box, think about what goes on anatomically biomechanically and let's see if we can improve the results we get with our patients. I thank you very much for your time.

    TAPE ENDS [0:29:40]