Hammertoes, the "stub"born truth behind the dozens (yes Dozens) of surgical solutions.
Zachary Lamb
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Alright so here we go I'm going to take on the daunting task of hammertoes......
Why so daunting? Just ask your doctor! If you're a podiatrist, foot and ankle surgeon, or any surgeon that deals with this problem you know that there are an innumerable amount of "solutions" and even if you have one that works, it probably only works MOST of the time. (Whatever that means) Not to mention when they go wrong they are always a pain in the you know what! Wouldn't it be nice to have a one sizes fits all option? It would but I will be honest, you wont find it in this article. To explain why lets first talk about what a hammertoe is and then give you "some" options.
What exactly is a hammer toe?
Quite simply a hammertoe is a deformity of the middle joint of the toe that causes your toe to bend downward so that it looks like a hammer from the side. The deformity can be caused by a lot of different things such as poor footwear, trauma, muscle/tendon/ligament imbalances, etc.. Regardless of the reasons, they often are painful and just plain old don’t look right.
Now there are conservative treatment options available and you should speak with your doctor about those however sometimes these conservative options are not enough and if you really want your toe(s) to be straight again you may need surgery. The issues with this surgery however stem from the fact that these joints, in your toes, are IN YOUR TOES, and unless you're an NBA superstar chances are they are SMALL! This means that there is not a lot of room to work with and it and can make for a tricky procedure.
Surgery today
Non-traditional forms of fixation implore typically one of two tactics. Nothing, or K-wires. The first option, while it seems, taboo (no fixation) runs on the idea that since the space is so small and really the bone is longer and calcified anyway that creating a gap in the joint will either allow for a fusion on its own (as if it were a fracture) or the space will alleviate the pain, form its own pseudo cartilage and return to normal function. Not a bad thought but its seems like a lot of "what ifs" which if I'm having surgery I'd want something more definite. So the other option is K-wires. By placing a k-wire through the center of the joint to hold them together this will allow for the joint to fuse.
Again this works the majority of the time however in addition to the fact that you would have a wire sticking out of your foot isn't fun and not to mention that what sometimes can also happen is that these bones "piston or slide back and forth on the wire so they never have the opportunity to fuse which then causes more pain and requirement to go back for another surgery or in a worst-case scenarios amputation
So what's the "solution"
There's really no straight answer to this. Initially one would think that there is a simple implant like a screw to hold things in place. While this is an option, its not always the best. A simple Google search for "hammertoe implants" will bring up dozens of different options! So which one is the best one then? Well that’s ultimately for you and your doctor to decide but far be it from me to not give you SOME info. In my opinion you should know the basics and that means that most all hammertoe implants fall under one of 4 categories:
1. metal
2. Plastic - aka PEEK
3. Bioabsorbable
4. Allograft.
Within each category there are plenty of companies with plenty of implants so what comes next is a brief list of a few of them with there features and benefits, pros and cons, etc. and that way you can have a more informed decision and conversation with your doctor/patient. Having knowledge is better than not right? (I will list the company's in Alphabetical Order)
- Metal
These are the most popular implants by far as they are very strong and secure when they do work. The biggest issue I have seen with pretty much all metal implants is the difficulty of removal when/if they fail or fusion is not obtained. Not a single one of the products below has a simple removal process so lets get that out of the way. That being said, when they work, they are solid.
This implant is essentially 2 screws that face opposite directions so when you put the screw in to the proximal bone the distal fragment is also being screwed into which then closes the gap. This is accomplished using a special drill that is a drill on one end and a screw driver on the other. The technique seems pretty straight forward however there is a possibility that the screw compression finishes too early and you are left with a gap where the bones should be touching.
This cannulated implant is a screw on one side and a staple on the other. Once you implant the screw in distally you push the staple in proximal and then shoot a K-wire through the center to "pop" open the staple. This means you have to hold the compression slightly while the wire is used which could lead to a little gaping but any surgeon who knows what they are doing shouldn't have any trouble with this guy.
This is a 3 piece device that places a screw in each end of the joint, then has a taper locking mechanism that fits in the center of one screw, then press fits and locks into the other. The best way I can imagine this is if you’ve ever played with Lego's? Well it's similar to how Lego wheels used to click tog with that grey plastic tube. If you don’t understand or you never played with Lego's…. Go check out there website!
I just have to say, this is a behemoth of an implant. It looks very secure but without having any experience with it, looks could be deceiving. Essentially this implant is 2 parts and there are 3 levels of "clicking" that can be achieved. You have to stop at one of the 3 clicks depending on when the bones are touching. I would assume this would be click number 3 but perhaps not. The only issue here aside from the size would be the question of what happens if you get to click number 3 and its still not bone on bone contact? Could pose an issue.
This is one of the more unique devices as it is a Nitnol staple that must be kept frozen before use and over time the memory will return to its shape. The only issue I see if that there is no way to control how much this implant expands and if you have poor bone quality, perhaps it could break the bone? Just something to think about.
This is also a cannulated implant that is screw in on one side with a nice little device inserter on one side and press fit on the other. I did not mention it before but cannulated is nice because many of times the toe isn't the only problem and surgeons like to hold the entire to straight, not just one joint. And if you have a solid implant all the way through this can become troublesome because there is not a lot of real-estate to work with here as we have discussed. The only hiccup with this implant isn't so much the implant but that there is a LOT of instrumentation for this tiny implant which can be overwhelming to some when other implants have simple methods.
2. Plastic - PEEK
PEEK is a medical grade plastic material what has very solid fixation methods with the added benefit that you can not see them on X-ray. That being said, they are not AS strong as metal implants but have the benefit of not being so difficult to remove in case it is needed.
This implant looks like a spear right out of the roman gladiator era. The barbs are on all 4 sides of the implant and facing in opposite directions to hold the bones in place. The barbs look very sharp and should work very well in holding the joint in place but they might be too sharp, the technique has the proximal side implanted first then the distal, which means if the distal bone is too hard, there is a chance you could push the proximal piece too far and since the bards work well, you might not be able to get it out. If the implant sits well though, the chances of this moving seem slim.
This one could have been a metal implant as well but it has a PEEK core that is cannulated! The metal "wrap" is wider than the implant itself which is supposed to give it grip. Also by having this PEEK core it keeps metal out of the joint but it confuses me how the implant really stays in place. Cool design and I'm sure it works, just different than most other implants that have a "ridged" fixation of some sort
This is very similar to the Wright Medical Phalinx, cannulated, screw in distally however this implant has the added benefit of not only being PEEK and having a nice little depth stop indicator which takes the guess work out of things, but there are 3 "fans" that get press fitted into the proximal bone rather that 2. This also means there is another potential stress riser for the implant to break but it should hold well.
This implant is a combination of screw and press fit and is also cannulated. At first glances the screw in portion looks very solid but the press fit seems a little short. I'm sure the company has tested this and made sure it is long enough but if it fails I would expect it to pop out the proximal phalanx which would make it easier to remove. It also has a square wedge in the center which I'm guessing doesn’t interfere with the bones connecting but something to think about
3. Bio Absorbable
These implants are fading out of style as can be seen by the fact that there are only two companies I could find that carry them. While they have the benefit of being absorbed by the body and not able to be seen on Xray they have the same potential "pistoning" issue that K-wires do. What is better though is that they don’t have to stick out of you foot for removal, and you probably wont need to remove them as they will most likely "disappear" (be remodeled into bone) within 6 months.
Arthrex - Trim it Pin (Image not available)
Have a tapered point that is just like a K-wire which allows for easy implantation. Has a technique for an All inside implant, which means the pin will stay within the joint instead of possibly coming out the tip of the toe.
Biomet - Orthosorb Pin (Image not available)
Are and easy to see dark purple color so there is no confusion in the surgery what is what. They are attached to a k-wire so once the k-wire is outside the bone it can be cut off for a clean implantation.
4. Allograft
In my opinion these are the best implants, while they may not have the best compression to hold the bones together, the benefit is that they ARE bone, so the body will incorporate them and in theory make it its own. And the best part is, if it doesn’t you haven't burned any bridges to potentially try something different. The one potential downside to these implants is that they are not as sturdy as the others so the chances for them to break either post operatively (DON’T WALK ON YOUR FOOT POST OP!) or even during implantation, could be higher.
Arthrex took the design of there very successful suture anchors and put them essentially end to end with this implant. While this implant doesn’t have anything to prevent it from spinning inside the toe, the fixation from pull out should keep everything tight and in place while the body heals.
This implant has a square pattern with indents and fans out to assist with preventing rotation and pullout. It has a nice little inserter that grabs onto the implant securely and claims to be the only implant not gamma irradiated sterilization, it could be true, I couldn’t find any info on the other to say otherwise. That being said, none of us are the Hulk so I don't know how important this is to you.
This implant has an Octagonal design to prevent the implant from spinning inside the toe and also has a nice little depth stop so you don’t go too far into the joint. This would be an issue since it would create a gap in the joint but since its bone I wouldn't expect an issue.
*Side Note* I'm not going to lie Wright medical and Paragon 28's look pretty much identical anyone else?
The bigger issue
As we talked about earlier these joints are very small. Besides the size however is the importance of bone quality and consistency. Every bone has a cortical layer which is the outer layer that is hard like concrete and a cancellous layer that is spongy and not very hard, like a sponge. This is where the real problems lies. You have 2 bones each with varying consistency's of cortical and cancellous bone. If there is too much cancellous bone, chances are no implant will hold because there isn't much to grab onto. Too much cortical bone and the implant may not be able to function properly in bone so hard. Each implant seems to have its optimal bone consistency, and while it would be nice to have 10-20 options available to open during your surgery, it would not be a cost efficient solution of the hospital, not to mention the patient since with these hammertoe procedures its really hard to tell the makeup of cortical and cancellous bone until you start utilizing one implant or the other, and could you imagine opening up 3-4 different implants for just a toe and no guarantee that it will work?
If you are a patient or a surgeon looking into a solution, I feel its important to have your favorite one in each material and hope for the best. These device companies are trying there best to come up with a one sizes fits all option but by seeing multiple companies with multiple options just goes to show you that there just isn't a perfect solution.
There is a lot to unpack in this article but I hope you really got some good information out of it! If you want to learn more about any of the products listed above I have put the links in each of the names just click and you'll be taken there! If you got some value out of this one (and let's be honest, I know you did) please share this with one of your fellow colleagues and let me know what you'd like to see me review next!