Section: CME Category: Surgery

Hammered Digit Syndrome

Harold Schoenhaus, DPM

Harold Schoenhaus, DPM discusses basic principles of the various treatment options currently available for hammered digit pathologies and deformities.

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Goals and Objectives
  1. Describe the etiology of hammertoes
  2. List indications for implants
  3. Describe how to prepare a joint for implantation
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    Release Date: 03/16/2018 Expiration Date: 12/31/2020

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    Harold Schoenhaus has nothing to disclose.

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


    Dr. Harold Schoenhaus: Our first speaker is the past president of the American College of Foot & Ankle Surgeons. The surgical editor of present e-Leaning, on the staff of Penn Presbyterian Medical Center, Temple University's School of Podiatric Medicine. Please welcome Dr. Harold Schoenhaus. That was going to be me. [Laughs]

    I thought I would share some thoughts on hammered digit syndrome. And I will tell you after 47 years of being in practice, what is simple in thought, doesn't necessarily always come out on the operating table. And worse yet, after everything is said and done the patient comes back to you and says my toe is still curled or my toe is rotated a little bit. You didn't do exactly what I thought you would do.

    Now for a resident, hammer toe is probably a procedure that either the first year resident is usually involved with. The third or fourth year residents whatever program you're associated with, they don't want to see the hammer toe. Well, it's like it's beyond them already. Well, I will tell you that should never be a philosophy that you espouse. It's never beyond you. These are challenging procedures. I have no conflicts to disclose to you. Learning objectives understand the etiology of hammer toes. Understand indications for implants, which have become probably one of the hotter topics and items that is out there for us. And that describe how to prepare a joint, if you're going to do implantation.

    When one looks at a typical hammer toe, you recognize there's involvement in multiple joints; metatarsophalangeal joint, proximal distal interphalangeal joints and we need to understand and look at each component of that joint complex, if you will, when you're going in to do a hammer toe repair. Some are associated with HAV deformity, as the hallux drips into a lateral direction, impinges upon the second toe and pushes it up.

    Interesting a patient may come into your office or be brought into the hospital for you to evaluate and they're coming in to have a second hammered digit fixed such as what you see on this picture. If you don't do something for the hallux where is that second toe going to go. So you have to be active and educational to the patient to explain to them the influence of the big toe on a hammer toe repair. And if you want that hammer toe to last, you got to get the bully out of the way, which is the big toe.

    So if we look across the metatarsophalangeal joint, I'm sure you all remember the anatomy but recognize these structures influence and participate in maintaining deforming forces. And the deformity that becomes more and more rigid as time goes on. So you look at extensor tendons on the dorsal aspect, whether it's a short extensor, long extensor, we come around the joint, we have interosseous muscles, we have lumbrical muscles, we have the plantar intrinsic, flexor digitorum brevis. Every one of these muscles has a specific function. And when we recognize what the intrinsic do as you pass the metatarsophalangeal joint, you realize the interosseous and lumbrical muscles help to hold this proximal phalanx against the supporting surface as you went to the propulsive phase. The foot comes off the ground, the digits stay on the supporting surface. Something has to stabilize the proximal and the middle and finally the distal. And from a plantar direction the flexor brevis is the next one that holds the middle phalanx down. And then the long flexor goes all the way to stabilize the great toe. There's polls from the side as well as dorsal and planner.

    So we need digital stability in propulsion. In order for that to happen in a normal foot, we need to re-supinate the foot. The rear foot has to come back to a more neutral position, slightly supinated that allows for stability of the extrinsic and intrinsic muscles across the joint complex. We recognize that in a hyperpronated foot and a Cavus foot

    [05:00]

    These are two foot types that develop digital contractures. Each one is different in etiology. When there's intrinsic fatigue usually associated with hyperpronation syndrome, the digits start to dorsiflex because the intrinsic can no longer stabilize because of intrinsic fatigue.

    The Cavus foot is a whole different animal. That’s a higher arch foot with plantar flex metatarsals. We are immediately in a compromised position at the metatarsophalangeal joint. And that is a more challenging type of hammer toe correction. And in cases of that type we may get into flexor tendon transfers to pull down the phalanx against the ground.

    A board question that you will typically see by the way about intrinsic, is there's one set of intrinsic that pass below the transverse metatarsal ligament as it goes up on to the proximal phalanx. It's not the planner interosseous, it's not the dorsal interosseous, it's the lumbricals. And you must be very careful to maintain lumbricals stability when you're doing hammer toe repairs.

    Now the dorsal and planner interosseous obviously are arising from contiguous surfaces. It's interesting the lumbricals are arising from the flexor digitorum longus. So when you're simply making an incision, recognize that there are structures you're going to encounter that are going to have to be either lengthened or transected and ultimately repaired. So simply going through approximate to phalangeal joint with a transverse dorsal incision, you’ll recognize that you're probably going to transect the extensor digitorum longus tendon. Now, there are times if you would like you can actually dissect the tendon away and go into the joint without interfering with it at all. More times than not however, you're using that incision to help maintain correction after your bone resection.

    There's a sling mechanism that's talked about. These are the members expansion of the extensor digitorum longus tendon. They almost like surround the metatarsophalangeal joint and you see it when you come back over the MPJ. And I'll tell you if you do hammer toe repair and do not address the contractures at the metatarsophalangeal joint, you're doomed to failure. The collateral ligaments are important in maintaining the formed position of the toes. These need to be dealt with simultaneously.

    So hammered digits syndrome, hyperpronation and cavus. And you can read this just as well as I can read it to you, but in essence these are factors associated with hyperpronation, intrinsic fatigue, fatigue, loss of propulsive stability, secondary contractures EDL EDB, flexion contractures, hallux abducto valgus which I showed you, secondary contractures of the interosseous muscles, bony adaptation, when joints stay in abnormal positions adaptation occurs. If the digit is hammered with dorsiflexion at the MPJ, you can bet the dorsal component of the joint has adapted somewhat to the pressure that's coming across that joint. So you must recognize that that is a component of deformity and you may need to do something but there's an osteotomy of metatarsal head in addition to a hammer toe repair. You need to relax the soft tissue structures of a joint. Though oftentimes I'll do simultaneous osteotomies such as a while of us of a lesser metatarsal when I'm fixing the hammer toe.

    So when we look at what's happening in the pronated foot versus a neutral foot, positions are compromised because of altered function of the tendons. Flexor tendons in a pronated foot will be altered, their pull will be more oblique and you will get some rotational component or at least the third, fourth and fifth digit; second toe usually comes back straight because the tendon is straight going to the digit, unless the hallux starts pushing it over. So if you're doing a repair, it's just as important to identify the fact that the etiology of hyperpronation is going to continue after your surgical approach.

    [10:00]

    So, I'm always treating patients to control the etiology such as an orthotic postoperatively. As digits contract, you get a retrograde force on metatarsals, all component in the hyperpronated foot, so we will often see concomitant keratomas beneath the second metatarsal or callus beneath the second metatarsal because of the retrograde force from the digit. This becomes a compounded problem as the patient continues to ambulate and get older and develop conditions that are going to require debridement from a conservative standpoint, orthotic control or surgical intervention.

    Now you can see that one picture, toes don't always look as simple as they may and they can be very crooked and very difficult to deal with. And we get into other deformities other arthritis such as rheumatoid arthritis or osteoarthritis of joints, individual or collectively and this could become a nightmare for you.

    You're all aware of swing phase substitution and phasic activity a muscle, I'm not going to go into that at this point, but it's important that you understand its influence. And you can see in patients who have equinus deformities, limitation of dorsiflexion at the ankle, the extensors, the anterior crural muscles overworked to try to dorsiflex the foot. And what's the influence of those tendons, it's the distal attachments and you could see how the toes begin to contract over time.

    Cavus is a whole different ballgame because of the component of a high arch. I hate cavus feet. I like to put a cavus foot under the front wheel in my car and run over it so I could flatten a damn thing, so then I could treat a flat foot. Cavus is a monster to deal with, especially with digital contractures because of the abnormal position of the digit on the metatarsal head and then the secondary contractures that take place. So, if you want to go in and do a major cavus reconstruction to get the toes to be straight, that's a choice you could make, not one that I favor.

    So let's talk about the proximal interphalangeal joint, which is really the one that we see most of the contractures taking place recognizing, however, the distal joint can also be curled and contracted. Not all toes have a simple dorsiflexion component at the MPJ and then a plantar flexion component at the proximal interphalangeal joint and an extension deformity at the distal joint. That's like your classic hammer toe. But what about the toe that's completely curled with dorsiflexion. Now, the flexor tendon becomes a more deforming force and you're going to elect to either cut that tendon simultaneously when you do the procedure or you're going to transfer it and use it as a force now that can hold down a proximal phalanx as you go into the propulsive phase of gait.

    Those simple resections, you've done these I'm sure. You expose the joint, you make a determination of what do you want to accomplish here. And in order to alleviate the contracture of the PIPJ you're usually removing the proximal head. And what direction should that be done in. Now, ultimately a decision is going to be made by you, what's going to happen after I do the hammer toe. What are you telling the patient? Is this toe going to be flexible when I'm done? Is it going to be able to move like a normal toe did or does move? Or is it going to be stiff? And I don't care what procedure you do in the soft tissue world, more of my hammer toes through the years ended up stiff at the proximal joint, some more so than others. Even just resecting the head, do you think that leaves a nice space, you close the joint, it moves nicely and over time you lose the motion.

    So it's almost like a fusion has taken place or a pseudo orthotic condition occurs at that proximal level. So if that's the case, what should you do? Do you take more bone off and run the risk of a flail toe? A flail toe is almost as bad as a hammer toe. Try to put a sock on their shoe on and the toe is like a floppy thing, piece of spaghetti. Patients don't like that either. So you got to be careful on how much bone you're going to resect.

    [15:00]

    So it's really not a good solution, if you think that's going to leave the space and allow for flexibility.

    So keeping in mind that the fusion is probably going to take place, do you do it primarily? Remove the cartilage off of the base of the middle phalanx and then just attach them? Put it together with a K-wire or do you go into implantation, which has become a very hot topic. And you could see probably eight or ten different hammer toe implants for the proximal interphalangeal joint. Now what we have done as a profession has embraced the concept of an implant. Wow, okay, I'm going to put an implant in that joint. If you compare implant to a K-wire, you could justify it in a sense because the K-wires sticking out the end of the toe. The patient doesn't like the fact that they see this thing, it gets caught on the bed sheets and they know it has to be removed. And we usually remove them around four weeks, three to four weeks. Fusion hasn't occurred at that point. So the K-wire is helpful in maintaining a position for a short period of time. But if there is any transverse plane deforming force on that digit such as from the hallux, you will drift the toe and actually watch it move with the hallux as it goes. You've lost the stability. You can even rotate that toe around the K-wire.

    So the implant has a purpose and we got to keep that in mind. Unfortunately, it costs about - an implant maybe eight to 800 to $1,000 for an implant, and the K-wire is $15, $20. In today's world of cost containment got to be careful. So we obviously do all of the soft tissue resections and we're going to remove the portion of bone and I'll go into that in a little bit more detail shortly.

    All right there are other toes that are hammered, a fifth toe rotational component to deformity. Again, and partially compensated foot types, like a rear foot varus or a forefoot varus, partially compensated, may have a component of a tailor's bunion, you get abducto varus of the fifth toe. That is a deformity in and of itself and you may want to do a procedure such as a Ruiz-Mora, a tacked down soft tissues of the fifth toe to maintain a position in addition to doing osseous work or you're going to do plastic reconstruction at the same time. So your incision, when it closes, will rotate the toe back into a fixed position. If you have a concomitant tailor's bunion you may have to do an osteotomy of the fifth metatarsal head along with the fifth toe correction though the patient has a nice straight digit when you're done.

    Bandaging is important and I will tell you that many times I see my patients come out of the OR and the residents have bandaged the toe in a position that it was worse than when it started. What are you thinking? So splintage, if you will, with Betadine is a great type of dressing to help maintain correct alignment and position. You watch hand surgeons, they are very careful on their bandaging and use a lot of inter digital into the web space bandaging with compression but no constriction to maintain straight position of all the toes. We are a little lacks in that.

    All right there's other procedures that help tacked down toes Ruiz-Mora is nice as a fifth toe procedure but I've also used it effectively on soft tissue of the second, third or even fourth digit. We actually webbed the toe down and use the soft tissues to hold it in a plantar position.

    All right here's a couple of examples of implants. You see one on the left side where an implant has a K-wire passing right through it. That may have advantage if you want to use that type because you correct the proximal interphalangeal joint. You've loosened, lengthened or release the soft tissues at the metatarsophalangeal joint and the K-wire is going to help maintain that toe at the MPJ in a straight position. Then you're going to take that out in three to four weeks. And the proximal interphalangeal joint is stabilized by the implant. And you can see many different types of implants. You can see some out here. You can look at the literature. You can see all the different types that have been introduced.

    [20:00]

    Everyone's got just a little bit different element. And I've always felt I want my procedure to be as simple as possible. I don't want to get into any intricate work on a toe in the operating theater. You have an implant that I can use very easily and very simply. It's a KISS principle, keep it simple stupid. Don't lengthen my OR time especially if I'm doing three or four hammer toes. So here is a couple of different ones that you see.

    Now K-wires can be very effective. There are many surgeons who take the posture, you don't need an implant, leave the damn wire in there and then take it out and you could have an excellent result. You can, as long as everything surrounding that toe is rectus as well. But here you see an example of an implant again with the K-wire going through the distal joint.

    Now if I have a distal contracture, I may want to release the soft tissue. I may even want to do an implant an arthroplasty of the distal interphalangeal joint. So here a K-wire implant is accomplishing both to maintain that toe in a straight position. Now look at the fifth toe on that, on the oblique view you see the amount of bone that was resected from the proximal at the phalangeal joint. Fifth toes, you got to be careful because if you resect too much bone you run the risk of a problem with flopping flail toe. You put your sock on then toe goes off to the right. There's different implants that have been used. There many times will do bunion correction as well as hammer toe correction osteotomy. So here's an example of a lapidus procedure, osteotomy of the second implant arthroplasty of the proximal at the phalangeal joint.

    There are other materials flexible rod types that I've used throughout the years, to maintain that flexibility of the toe. Does they work all the time? No, I've even seen these rods break. It’s silicone, bone doesn't like silicone that much so I really have come away from that. There are flexor stabilization rods. There's a good example of that second toe sticking up and the amount of bone that is anticipated to be resected. But if you don't do something to release the MPJ that toe sticks up in the air. Good, I'll put an implant in there, no good.

    Some implants have a flexion component within them. Fifteen degrees of flexion for example or 10 degrees of flexion, so that the patient's toe doesn't just standout straight, but has some curvature to it, hoping that that will mimic what a normal toe might look like and even function.

    Look at that HAV on that patient, pushing up against the second toe. This toe has maintained stability of the MPJ, but once you resected head of the proximal phalanx that's the site where that toe will deviate a lateral direction.

    Incisional planning is important. You certainly want to know what you're trying to accomplish with your incisions. Obviously the patient who has a keratoma on the digit would like to see that removed and we obviously do that concomitantly and then just go about doing whatever procedure you're going to be doing. And here's an example of it where the lengthy incision for our hammer toe because I'm going down to that MPJ released the hood ligament or release my collaterals if I have to lengthen tendon extensor or transect the brevis, I will do that simultaneously.

    Preparation of the phalanx whether it's the middle or the proximal, these companies have beautiful little brochures for you, so that you go down the central part of the canal. And intraoperative x-rays are helpful if you don't think you could find that canal. And here's one of those flexible rods going in. Then repair the extensor tendon, it still needs to function. We don't just cut it and then hyper load in adjacent digit. Goes through remaining tension coming from the muscle in the leg going through four digitations now changes to three digitations. So you have more of a force of deformity on your other digits. Here's an example with an implant.

    [25:00]

    You see that little ball in the joint. It’s always looked good, but look what's happening at that joint. You got flexible rods; the toe can just be deviated over. Here's another influencing deforming force, though all of that is done simultaneously. So what I try to get across is hammer toe is not such a simple procedure. We like to think of it of all the reconstructions we do, the hammer toe is so simple, it's not. So please use discretion and treat it as a deformity that deals with the rest of the foot as well.

    I thank you for your time.

    TAPE ENDS - [25:42]