All right, if everybody can come take their seats, we're going to get started with the next session. This is going to take us up to the lunch break. Our next section is going to be on hand and wrist soft tissue trauma. Our first speaker is going to be Sanj Kakkar from the Mayo Clinic to talk about dislocations and ligament injuries of the hand. Morning, everybody. It's a real honor to be here. And really, this is one of the highlights for me for this year, teaching at this course. Today, what we'll be talking about, we'll talk about hand dislocations. We'll start off with the digits, and then we'll go over to the thumb. So these are my disclosures. None are really relevant for this. I would like to acknowledge my partner, Dave Dennison, for some of the expert in terms of the pro sections that he did a while ago in the anatomy of this, and we'll be showing some of these. A lot of the references that have come from this are included in your handouts, and I've tried to sort of take from previous exam questions and really hone it in on this. So a lot of this is just basically factual information for passing the test. When you look through your handouts, you'll see those areas where I put asterisks, and that's really what have been emphasized in previous test questions. So that's the sort of areas that you really want to hone in your studying the last minute before the exam. And we'll simply start from proximal to distal. So in terms of the MCP joint, all of these joints are basically boxes, and the roof of the box is the dorsal capsule, the floor is the volar plate, and on the sides you have the collateral ligaments. The MCP joint's a little bit different, so if you imagine a sagittal view, that from a dorsal to volar aspect, it's wider than from a proximal to distal, and as a result of this, the collateral ligaments are taut at 90 degrees of flexion, and that's called the so-called cam effect. And so when you're testing the true collateral ligament and the dorsal capsule, so if you imagine you bend your finger down, what's going to be taut? It's going to be the dorsal capsule and the true collateral ligaments. That's where you're testing at 90 degrees of flexion, and that's why we tend to immobilize in the safe position. Whereas in full extension, what you're testing there is the volar plate and the accessory collateral ligaments. But don't forget this structure, and they sometimes test this, the deep transverse intermetacarpal ligament, and that gives you stability in the axial and the coronal planes, and it attaches to the volar plate, and so sometimes you need to be thinking about that for instability, especially in high-energy traumas. Now most dislocations, if you have to pick dorsal or volar for the hand for the test, most are dorsal in nature. And so the most common are the index and small finger, but what I, you know, your eyes in the test will be drawn to the MCP joint, and you'll see it's dislocated. But as I've asterisked here, there is a common injury pattern where the DIP joint is also dislocated, so don't miss that when you're looking at the x-ray, because that's how they'll try and catch you out in terms of other injuries. And essentially what the key determinant here is can you reduce these open and closed, and what's preventing the reduction? And the number one structure that's preventing the reduction for a dorsal dislocation is the volar plate. Sort of makes sense, proximal phalanx goes dorsal to the metacarpal head, the volar plate gets entrapped. But in addition to this, you also have to appreciate there's some nuances on the index finger and the small finger. So on the index finger, in addition to the volar plate, you have to be worried about a noose effect where the metacarpal head gets entrapped between the flexor tendons ulnarly and the lumbricals radially. And if you're gonna approach this from a Palmer approach, the most common structure at risk is the radial digital nerve, because everything is now more superficial and it's right underneath the skin. Whereas the small finger, in addition to the volar plate, remember that's number one, but if they ask you what's the second most common, it's the abductor digitae minimae on the ulnar side and the flexors and the lumbricals on the radial side. So now in terms of simple and complex, essentially what are we talking about? Well simple dislocations are where you can reduce these. And the reduction maneuver is not traction or hyperextension, because what you'll do then is inadvertently draw the volar plate in and convert a simple dislocation to a complex dislocation, and you can't reduce that in a closed manner. And also remember we talked about the flexor tendons, so here what you have to do is flex the wrist down and you're relaxing the flexor tendons, and in this way you're able to simply pull and push the metacarpal head down. And most of these tend to be stable, so the next treatment option is early range of motion. So what about complex? This is what I'll try and catch you out. And the key determinant here is looking at that X-ray. So when you look at that X-ray, what you'll see is that that sesamoid is entrapped within the joint, and that's your clue that you're probably not gonna be able to reduce this in a closed manner. You need to open this up. The other determinant in addition to the sesamoids is look at the X-ray, because oftentimes they'll have a metacarpal head fracture. And if they're having a metacarpal head fracture, they're sort of pushing you down the avenue or you're gonna go dorsal and volar. And most of these are easily addressed from a dorsal approach than a volar approach. Sorry, there's a lot to go through, so we're trying to fly through this. But this is all in your handouts as well. I just wanna sort of draw on the salient points for the test. So dorsal approach, the advantage here is that you incise the capsule. You can push the volar plate palmly, and also at the same time you can see here, you can address those metacarpal head fractures, which are harder to get from a volar side. If you do go volar, remember, the number one structure at risk is the radial digital nerve. It's right there, so you need to watch out for that and retract it out of harm's way. You then need to release the A1 pulley, and by doing so, you'll release the flexor tendons. Remember that's a noose around the metacarpal head, and it'll allow you to get your reduction. You can also extract the volar plate, repair it if you want to, you don't have to, and then start early range of motion. Now that was dorsal MCP joint dislocations. Much more rare are volar MCP joint dislocations. I just put this in just for completeness sake. One of the key things to remember is where does the volar plate, believe it or not, they may ask this, is where does the volar plate come off? For volar MCP joint dislocations, the volar plate comes off distally, but for dorsal MCP joint dislocations, the volar plate tends to come off the metacarpal head, so that's why I put that in the asterisk there. The other thing is that they like to ask is what are the other blocking structures, and especially for the border digits, the juncturi tendini, believe it or not, can become a restraint to reducing these dislocations, so that's why I put it in there. PIP joint, they love the PIP joint. If there are any joint that they're gonna ask in the digit, it's most likely the PIP joint. Again, the anatomy is pretty similar, a box construct with a volar plate, dorsal capsule, and collateral ligaments. In terms of flexion, a 30 degrees of flexion, again, you're tightening the dorsal capsule, so you're testing that, as well as the true collateral ligaments, as well as in full extension, it's the volar plate, and what attaches to the volar plate is the accessory collateral ligaments. And this is a nice diagram done by Dick Berger, and I think it highlights it nicely in terms of the anatomy to try and understand this. So if you look at this, if you look at the intact specimen, you can see how the true collateral ligament is dorsal to the accessory collateral ligament, and the true collateral ligament inserts onto the base of the middle phalanx. If you look at the accessory collateral ligament, however, that's more in line with the A3 pulley and the volar plate. There's some confusion about what the check rein ligament is, and simply that's a proximal extension of the volar plate on the proximal phalanx, and that's all the check rein ligament is. So when you see this type of injury, and you'll have commonly seen this in clinic, where you have this avulsion fracture of the base of the PIP joint, essentially you can see that the true collateral ligament is still attached to the volar aspect of the base of the middle phalanx. So that joint is stable. And this is the common sort of x-ray that you will see, and in the test, the number one complication of this injury is not instability, it's actually a flexion contracture, and that's why I put that there. Now what happens if you break it a little bit more and you get a larger fragment? So you can see from this diagram by Dr. Berger how that true collateral ligament is now attached to that fracture fragment. And so there's nothing preventing from that proximal phalanx from going out dorsal, and that's where you get the instability pattern. If there's nothing I teach you today, just remember these two numbers. In terms of instability, when it comes to the test for PIP joint fracture dislocations, 40% tends to be the answer for the PIP joint. For the DIP joint, it's 50%. Sorry, that's not in your handout. I just sort of thought about an easy way to try and put it all together. So I just wanted to show you that. So 40% for the PIP joint and 50% for the DIP joint for fracture dislocations. Okay, so when you're looking at the x-ray, the key thing is the sagittal view or the lateral view of the PIP joint. You want to make sure it's a concentric reduction. And be wary of this. You can see here you have this so-called V sign where you have joint subluxation. It may be subtle, but the joint has to be concentric. And if it's not, that's where you're looking at some form of instability and you need to do something about this. Remember, for irreducible dislocations of the PIP joint, the primary offending structure is the volar plate. You can either go dorsal, you can either go volar to reduce this, it's dealer's choice, but that's the number one structure that's preventing reduction. Okay, dorsal PIP joint dislocations tend to be more common than any of the other two. We'll go over the other two in a minute. The volar plate shears off the base of the middle phalanx. This is a palmar dislocation, a PIP joint dislocation. And the number one structure that you worry about here after reduction is injury to the central slip, okay? So that's why I've put that there. And in terms of a lateral PIP joint dislocation, it makes sense. You've injured one of the collateral ligaments, and remember the collateral ligaments also insert into the volar plate, so you may have injured that as well. Treatment principles to get the joint reduced in any way that you can and start early range of motion as much as possible. Okay, so in terms of dorsal PIP joint dislocations, essentially three types. The first one is a subluxation, the joint's not fully dislocated. The second one is when you see this. And so remember that diagram by Dr. Berger. So what you'll see in this one, you see there's true bayonet apposition of the middle phalanx over the metacarpal head, but the true collateral ligament is actually still intact. So if you reduce these, these patients tend to be stable. And a fracture dislocation is one that causes much confusion, and that's why I talked to you about the 40%. If it's less than 40% in general, these tend to be more stable. If it's more than 40%, they tend to be unstable, and you need to do some form of further surgical intervention. Most of the time, you can reduce these, get the patients moving early. The number one complication is not instability. If the fracture fragment is less than 40%, it's stiffness. So read the question carefully. Regular PIP joint dislocation, if they're gonna ask you a question on this, it's what's the injury. So if you imagine the middle phalanx is sheared palmly, what inserts from the dorsum of the middle phalanx? It's the central slip. So that's the one that you need to protect post-operatively or post-treatment. And what you're doing is essentially you reduce the joint, keep the PIP joint in full extension, and start DIP joint range of motion. In this way, it gives a chance for the central slip to heal, but also by doing DIP motion, you're causing the lateral bands to migrate dorsal, and you don't get a boutonniere deformity. If there's a large fracture fragment, then you're gonna fix this, and I'll show you a case example in a second. Lateral PIP joint dislocation, essentially the collateral ligament on one side is injured as well as the volar plate. You wanna get a concentric reduction and start early range of motion, probably buddy taping and getting range of motion, otherwise these patients get stiff. There was one series out there about trying to treat these primarily with operative intervention primarily in athletes, allowing early range of motion. But I think operative indication is rare for the test perspective as long as the joint is well reduced, and then you start doing early range of motion. PIP joint fracture dislocations, they love this, okay. The dorsal lip here, remember, the central slip inserts here, so that's what you need to fix. The volar fracture dislocation where you have, sorry, the dorsal PIP joint fracture dislocation where you have a volar buttress injury, and then you get these pilon fractures, and so we'll go through these sequentially. So in terms of your handout, I think you have this slide in there. I would advocate just putting some of this to memory because it sort of tells you when you can treat these non-operatively and when you need to operate. Okay, so when you get the dorsal lip fracture dislocation, okay. So essentially here, you can see on the x-ray, you have this dorsal avulsion fracture. It's relatively small, and if it's small like this, less than 25%, splint the PIP joint in extension to protect the central slip. Work on early DIP joint range of motion. Otherwise, the number one complication for this is a boutonniere deformity. When it's greater than 25%, however, that's when you're looking to fix this. That's a large fracture fragment. It also involves the articular surface, and so the treatment here is really not non-operative. It's more operative intervention. Volar PIP injuries, okay. So this now is when you're injuring the volar buttress of the base of the middle phalanx. Remember, the volar buttress is there to prevent the middle phalanx from going dorsal. So in general, when it's less than 30%, they're stable. 40% is the answer for the test. Anything more than 40% tends to signify instability, and it comes down to that diagram by Dr. Berger that hopefully now you understand. When it's more than 40%, the true collateral ligament is now no longer associated with the middle phalanx, and that's when you get instability. Okay, so just to hone in on that point. So if you understand that, then you can understand the sort of treatment options, okay. So again, look at the lateral radiograph post-reduction, and ensure that the reduction is concentric and you don't have that V sign. And if you don't have it, you can start early range of motion. However, if there's subluxation, then you're sort of trying to get the PIP joint in the degree of flexion to see when is that joint reduced. And that's where the concept of extension block splinting comes into it. In general, less than 20 to 30% of the volar aspect of the middle phalanx treat non-operatively. Greater than that, think operative intervention. And there's a myriad of different options out there. We're not gonna go through every one, but we'll go through the ones that commonly appear on the exam. Okay, so this was a study out of our institution where it was less than 40%. Remember, 40% for the PIP joint. When it was less than 40%, patients were treated with extension block splinting, and they were gradually, every week came out of it in more extension by 10 to 15 degrees. And you'll see that patients actually had a good range of motion in terms of flexion, but a complication was the extensor lag, i.e. stiffness. Greater than 40%. So now here, that fragment is wanting to come out dorsal, so you have to put something to block it. So you can put an extension block splint, a pin, so essentially you have the joint reduced, and you put a pin in the metacarpal, keep the joint reduced, and start working on range of motion. You can see the outcomes weren't too bad. Mark Vitale presented his outcomes in 2011, and from Steve Vegas' work in 1992, the exam tends to look at what are the complications for extension blocks pinning. Stands to reason, stiffness. Whenever the PIP joint is injured, stiffness. But when you have a pin in there, we all know about pin tract infection. Okay, what about the force couple devices? Many different types of systems out there on the market in terms of the complications. Again, infection. But you need to watch these patients carefully because they can lose their reduction. And what is the concept of this? Essentially, what you're doing is that you're imparting a dorsal to volar force to prevent the middle phalanx from dislocating out the back. So for that to work, you have to have the dorsal lip of the middle phalanx intact. So if you have a pilon fracture, this is probably not gonna work because that dorsal force is now transmitted, and you're gonna get volar instability. So in this case, you can see how the dorsal cortex is intact, and using this force couple device, pushing that middle phalanx from dorsal to volar, the PIP joint is reduced. And just as one series out there, patients generally do pretty well. There is a risk of arthrosis and stiffness, rarely instability. What about open reduction internal fixation? In terms of the test, if you have to pick this, you only pick this if it's greater than 40%, and there's a larger fragment. If it's a one fragment, these are amenable to operative fixation. And the study for this comes out from Hamilton, which basically showed, you can see, if it's highly comminuted, patients didn't do as well as if it was a single fragment. So that's where that comes from. The two other main types are volar plate hemiarthroplasty, and essentially what you're doing is that you're taking the volar plate to act as a checker, and you're putting it into the fracture to hold it down. So if you think about that conceptually, if you're putting the volar plate in, you tend to wanna get a flexion contracture, and that's what the studies sort of bear out. And so a study by Malarich showed that if you treat these acutely, patients do better than if they're treated chronically, but they do have a dislocation rate if it's over 50%. So if it's over 50% for the test, start thinking the next treatment that I'll talk to you about, and that's the hemihemate arthroplasty. I think there's good data out on this treatment by Bill Hastings showing a good treatment option for PIP joint fracture dislocations. And essentially what you're doing is taking the hemihemate, flipping it around, and reconstituting that volar buttress. There was a study basically looking at the size of the defect of the middle phalanx, be that all the way from 40 to 80%, and comparing volar plate arthroplasty to hemihemate. And the conclusion was that the hemihemate was better in terms of resisting that dorsal instability. And the greater the degree of instability, so for example, for a 60% defect, you can see the flexion contracture for volar plate hemiarthroplasty was 80 degrees. Ryan Kalfi presented his work on hemihemates, and basically the take-home point, they did well even in the subacute stage. Acute did better than subacute. So if you have an acute fracture dislocation greater than 50%, probably the answer is hemihemate arthroplasty. And there's many series out there. This was a meta-analysis that tried to sort of group all the studies together. And I put the complication rate down there for you because they may ask that. And so the number one complication rate for a hemihemate is not a flexion contracture, it's radiographic arthrosis. Not clinical arthrosis, radiographic arthrosis. Okay, pilon fracture, the take-home point for this is that a force-coupled device won't work because now you're transmitting the force from dorsal to volar, you get volar instability. Essentially, you wanna do some form of skeletal traction. Peter Stern compared three types of treatment, splinting, skeletal traction, and open reduction internal fixation. Those had skeletal traction did better for pilon, so that would be your answer. Okay, DIP joint, quickly moving on. Mallet deformity, we're all aware of this. It's either from a closed force flexion or hyperextension injury. And patients come into the office primarily with the extensor lag. In terms of the most common finger, the answer is the long finger. It's always that finger for some reason. Patients love to come and show you that finger, but it's always that finger. And this is a study of why that is. In terms of the classification, two types of classification, a temporal one, acute or chronic, but I think most people use this classification, which is the Doyle's classification. And essentially, it's a four-stage classification where type one is the most simple one that we see. We have a mallet, extensor tendon injury, all the way to the fracture dislocations that we see. And I'll try and give you some pearls of how to manage the fracture dislocation answer. So in terms of treatments, do you need to immobilize the PIP joint? The answer is no. You can leave the PIP joint alone unless they have a swan neck deformity. If they don't, splinting of the DIP joint is key. And I put this in there. You might think, well, why has he put that? It's an esoteric comment. They actually tested this one year. So when the terminal tendon, the extensor tendon, heals by over a millimeter in length, extra length, you get a 25 degree extensor lag. So you just have to commit that to memory. There's no way of understanding that. A study by Okafor treating patients with a mallet. Some had fractures, some didn't. Take home point is most patients actually did very well with minimal functional impairment if they had a fracture or did not have a fracture. Okay, so what about those that have a fracture? Because that sort of tends to bring up a lot of confusion. So what about this fracture? So this is a Seymour fracture. Okay, this is a pediatric growth plate injury. Don't miss this. This is an open fracture. Needs to have some form of operative intervention. And essentially what's happened is that the nail bed gets entrapped in the fracture fragment. And so you need to go in, remove the nail bed. Actually, if you reduce the fracture, it's relatively stable. You don't really need to put a pin in. But if you miss this, the number one risk factor here is an infection. What about fractures? How do we treat those? So in terms of non-operative treatment, study by Dr. Schneider of mallet fractures, six were treated with just pinning. The majority were treated non-operatively. And what they noticed was that essentially everybody did well, even if there was volar subluxation. So I know that there had been dogma, if you have volar subluxation of the fracture fragment, you need to operate on that. The literature sort of tends to signify that you don't have to operate on those. And for the test, I'd probably argue non-operative treatment. This is another study where they had closed mallet fingers, nine with a simple extensor tendon injury, and 13 who had that volar subluxation. And how did they do? And essentially, they did the same. They treated non-operatively. But those that did have a volar subluxation had these three issues. So they had a higher extensor lag, they had a dorsal bump, and they had radiographic more arthritis. Don't think they'll ask you those complications on the test, but the take-home point was non-operative treatment was the way to go. If you are gonna operate, what's the literature? A study out of our institution, essentially patients did well with pin fixation. But I think this is a take-home point for the treatment of mallet fingers. Study by Dr. Stern. If you're gonna treat them in a splint, complication, number one complication is skin irritation. If you're gonna operate, then there are a myriad of different complications. You can see in their series, one patient needed an amputation. So I would say for the test, even if there's volar subluxation, non-operative treatment is probably the way to go unless it's open. Dorsal DIP joint fracture dislocations are rare. You need to be thinking about an FDP avulsion fracture. Do we have time for questions? Oh, okay, all right. So just next talk, okay.

hand and wrist trauma

ligament injuries

dislocations

surgical techniques

treatment options

complications