Episode 148 | Breaking Down ACL Graft Types and The Big 3

What is up guys, and welcome back to another episode on the ACL Athlete Podcast. So today is episode 148 and we are breaking down ACL graft types and the big three. The main goal of this episode is to share a very simple and general overview about the different ACL graft types that exist in current-day ACL surgery and reconstruction. I’m not going to talk about the pros and cons or share any opinions about which one is better than the other.

I’m sure everyone has these questions. And there’s a lot of context around this. This is why I just want today to be focused on breaking these down to understand what are the different types that exist, what are the big three, and what are the categories, to just make this super simple. Especially, any of my ACLers who are going through this process, trying to understand the different graft types and then what is potentially proposed to you. And then for any of my clinical or for any of my coaches out there for anyone who’s listening on the supporting side to be able to just see what are those different options that you might be working with and what’s common in this space. 

To start this off, we’ve got two main categories for ACL graft types. You have your allograft which is a cadaver graft. This is something that comes from, yes, a dead body or a cadaver. And this is something that is usually taken from the patellar tendon, semitendinosus which we will talk about, which is a part of your hamstring muscle group. Same thing with the gracilis, your quadricep tendon or Achilles. And there might be other ones that also exist and are floating out there, but these are usually the most common ones that are used from a cadaver standpoint. This is not taken from your own body and instead is taken from someone else. And then this is what is used as your ACL graft for your ACL reconstruction.

And then there’s autografts. Autografts are taken from your own body and this is where the big three comes in. The big three are the patellar tendon, the hamstring tendon and the quadriceps tendon. For the longest time, the patellar tendon and hamstring tendon were the two major ones. And of recent years, the quadriceps tendon has become involved in a lot of procedures. This all comes back to really surgeon’s backgrounds, the way that they’re trained, and maybe the type of grafts that they just love to harvest. And maybe the results that they’re also seeing. They take all of these things into consideration. A lot of times training and their background is biased based on what it is that they learned in school and residency and into the fellowship and whatnot. But sure, there are a lot of things that change within their practices but these are typically the big three. 

It’s very rare for surgeons to do all of these particular procedures and do a high number of them just because there’s such a variety. Usually, they have the particular ones that they cater to. They might be like, all right, I like to do the quad tendon. There’s a lot of people here in Atlanta, a lot of surgeons who love to do the quad tendon. Maybe they’re more biased towards patellar tendon, maybe they are an older surgeon. So then therefore they might be biased toward the patellar tendon or hamstring tendon, since the quads is a little bit newer. And then maybe they do just cadaver grafts. These are all things to consider with your particular surgeon in terms of graft types. There are episodes and content related to how to best go about choosing your graft type and part of this is also picking your surgeon and part of this is also what graft types they are doing most often. But the big three here are the patellar tendon, hamstring tendon, and quadriceps tendon. 

Let’s break these three down. The patellar tendon is often called the BTB or bone patellar tendon bone. The reason for this is because when you look at the patellar tendon, this is the tendon that is from below your kneecap into this bone called the tibial tuberosity. This is harvested from that middle third, one-third of that patellar tendon. They take the middle portion of that and they’ll take the bone from both ends. They’ll take a little bit of bone from your tibial tuberosity which is just a small protrusion that is sticking out from where the patellar tendon inserts down on the shin bone. And then you have the top piece where that patellar tendon is starting or its origin on that bottom of the patella or your kneecap. And so they’ll take a small piece of bone from each side and these will be bony plugs. And so when they go to put this in for your ACL reconstruction, they will actually anchor these bony plugs in at the end.

And there tends to be a little bit of a quicker formation of bone in terms of that healing and that graft coming into that site. Pros and cons and everything, we’re not going to talk about that today, but this is just something to think about with this surgery. And it’s just what’s most commonly done with the bone patellar tendon bone.

For the hamstring tendon, this is what I had actually for my two ACL reconstructions. I had my first one in high school. That surgeon really didn’t have a choice there. We really didn’t even know that options existed. They were just like, you know, we do hamstring tendons. And so that’s what I got. And then in college toward my other ACL, and this is where the surgeon recommended hamstring tendon. I knew a little bit more, but this is where there was a suggestion based on since I had a previous hamstring tendon on one side to just do that on the other side. That’s a conversation for a different day. But at the time I was in college, I didn’t really know a ton about this world. This is just something where I was just like, all right, this is a reputable surgeon, I’ll just go with their suggestion. 

The hamstring tendon, getting back to it, is harvested from the medial hamstring which is on the inside of the knee. When you think about your muscle group for the hamstrings, you have some that are attached to the outside of your leg of your knee and then you have some that attach on the inside. The inside ones are semitendinosus and semimembranosus. If you guys want to look this up via anatomy, you can. But these are inserted into the medial side or the inside of the knee. This helps to flex your knee and extend your hip. This is something where the semitendinosus is what’s often taken here and possibly part of your adductor which is the gracilis tendon. So that comes to the inside of the knee as well. This is just based on the surgeon’s preferences, and training. It might come back to the size of the person where the tendon might not be long enough where they can bundle it, in order to make it thick enough for an ACL graft. They might take some of the gracilis in order to do that. Essentially, that hamstring tendon is going to be bundled, it’s going to be taken from the medial hamstrings which semitendinosus is the number one, and then maybe combined with gracilis is number two. 

And then we have our quadriceps tendon, often referred to as the quad tendon graft. This is harvested from the middle one-third, similar to the patellar tendon, but this is on the quadriceps tendon. When you look at your quads or your thigh muscles, it comes down to a point where it connects to your kneecap. This is where the quadriceps tendon is found and this is where they will take that middle one-third of it. Sometimes it will be taken with a bony plug off the patella. Just like that patellar tendon where there are bony plugs on both sides. You can’t get that with a quad tendon just because it’s coming from the muscle itself. Therefore, on one side, there can be bone taken from that patella or that kneecap bone. A lot of times, it’s not taken. Again, coming back to the surgeon’s preferences, I would say, locally here, from what we see, they do not take as much of a bone from your patella, but it just depends. I’ve seen athletes with it before.

These are your big three: you have your patellar tendon, you have your hamstring tendon, and you have the quadriceps tendon. As of right now, this is how we see the autograft for ACL reconstruction. One thing I do want to note with these tissues that are taken from your own body is that that’s where we call this a donor site or where it’s been harvested, where this tendon was taken to be used as your ACL reconstructed graft.

This specifically needs to be treated as a secondary insult or injury and be managed appropriately. I think that this is something that gets missed very often is that we go into the ACL rehab process and this injury itself, or where this has been harvested or that donor site doesn’t get managed very well from the get-go. The way that we need to look at this is essentially that patellar tendon and quad tendon because of where it is taken and their anatomy are forms of tendinopathy or tendonitis in a sense. This is an umbrella term (tendinopathy) and so this is something that we need to manage in that form. Of course, allowing it to heal from that acute trauma and harvesting. But then it needs to be managed and loaded appropriately versus just assuming it’ll just adhere down and it’ll just heal with the process which it will, but it’s something that also needs to be loaded to be built back up, especially after a time of unloading and that graft being taken.

For the hamstring tendon, it’s a Grade III muscle strain or tendinopathy combined, depending on the type of procedure, especially with that gracilis taken. Or is it just the semitendinosus taken and the procedure and the technique? But this is a little different because that muscle directly is implicated versus your quadricep tendon or your patellar tendon. With the patellar tendon, a direct muscle attachment is not impacted. And even with a quad tendon, you still have attachments going with the semitendinosus. They’re actually taking that whole tendon so that muscle — the research is very interesting on what happens to that muscle. Sometimes it just atrophies and goes away, sometimes it attaches to the semimembranosus. That is something that is still out there in terms of the research and what happens to it. This is something that we even looked at with my PT school, a doctorate where we did research and MRIs on this. It was interesting to see just the variety that we saw with people with hamstring tendons and what happened to the remaining semitendinosus. This is something to consider with these donor sites is just making sure that these can be managed and treated as forms of tendinopathy or muscle strain. Attacking those sites early and progressively and listening to those areas can help with managing the donor site, pain, and discomfort that we see a lot of athletes come in with later because it has been mismanaged. 

The last thing I’ll add here is one additional procedure I wanted to take note that can be done is an LET which is a lateral extra-articular tenodesis. This is where they take part of the IT band and anchor it to the outside of the knee. Usually, it’s indicated for rotational instability or maybe an athlete has had possible multiple tears. This is something that a surgeon might recommend. It’s a technique that is done in addition to ACL reconstruction, so not in replacement, but it’s usually an add-on procedure. Someone will get an ACL reconstruction with a certain graft type, and then they’ll get an LET combined with that. And so that is something that has picked up a little bit more steam, if you will, especially more for the right candidates, but just know that this is not the majority of ACL reconstructions.

Before you go and talk to your surgeon about, hey, I want to do an LET, just make sure that they do that. But then the other thing is, it needs to be the right person. This is still not indicated for the majority, as I said. And if they do it, they will likely suggest it based on your case. If they don’t, then it’s something that probably doesn’t need to be relevant to your case. But again, it’s on an individual case-by-case basis. This is also something that we tend to see a little bit more outside of the U.S., but it is still done here in the U.S. It’s just more common that we see, especially in Europe and in other parts of the world. The U.S. is starting to do more and more of it based on training. But again, it just depends on the surgeon’s preferences and the case warrants doing it. 

The reason that I bring this up is that a lot of times we’ll see athletes and they’ll say they had an LET done. I ask them if they know what it is and they don’t. This is something that I think is important because it can help with explaining maybe another area that might be more uncomfortable, maybe their knee is more sensitive or painful. Just something to keep in mind and also something to know about your history, especially with an LET being added. So that’s why I want to bring it up in case these words or letters do come and you know what that looks like. 

And while other procedures do exist in the world of ACL surgeries, the goal here was to discuss the major graft types and understand most importantly where they came from, what are the big three, and being able to just go about making a better-informed decision, which is a big part of this podcast, right? To help educate you on different pieces of the ACL rehab process. This is for you to understand the two main categories which are allograft and autograft. Then from there, the autograft which is taken from your own body, has the patellar tendon, hamstring tendon and quadriceps tendon. One of the things I had mentioned was to just be mindful of that donor site. Maybe it’s something that you are able to talk to your PT about to just make sure that’s being addressed appropriately. And then the additional procedure that has become a bit more common or that is seeing more frequency is the LET with the right cases, so that is just something in addition to being aware of.

Again, this is something that is very general, very simple, no pros and cons here, just laying out the information in terms of what you will see. If you go to see your surgeon and you’re trying to figure out, alright, well, what graft types are available. And then from there, it’s making a decision based on your specific case. 

We will do a podcast episode where we break down the pros and cons of the graft types and procedures. That will definitely be a very filled episode because there’s a lot of nuances to it. There’s no perfect graft type for this. Otherwise, the other ones wouldn’t exist. This is why we have to just go with what makes sense for our goals, what the surgeon does, and what seems to make the most sense for our own ACL journey.

I hope that this was helpful team. If you have any questions, you know where to find us. This is your host, Ravi Patel, signing off.