Question: Can you explain the choices in grafts for an anterior cruciate ligament (ACL) reconstruction?
Answer: When talking about reconstructing or rebuilding an anterior cruciate ligament after you've torn it there are two graft choices in general. One is called an autograft, in which we are taking the tissue to rebuild the ligament from your own knee or from the opposite knee in some cases. And the other choice is what we call an allograft, which is taking the tissue from a donor -- in most cases from a tissue bank.
The structures that we use to rebuild the ligament can vary from the patellar tendon; in other words, from your own knee or from a donor. We'll take the middle third of your patellar tendon with a little bit of bone on either end to replace your original ligament. Another common tissue that we now use more frequently is hamstring tendons, and that can be two of your hamstring tendons from your inner portion of the thigh and knee -- the so-called semitendinosis and gracilis tendons -- or we can take those, again, from a donor.
From donor tissue we can use other tendons or other ligaments that you obviously couldn't use from your own legs, such as your ankle tendons -- the anterior tibialis or the posterior tibialis. People have used quadriceps tendons, the illiotibial band, a lot of different structures.
But the main choice for you as a patient is to decide whether you want to use tissue from your own body or tissue from a donor. And there's pros and cons to both and different risks.
It turns out that in terms of outcome, all the structures or the tissue options we've talked about end up being about equal. We really can't define a difference in the ultimate outcome -- stability, function, strength of the graft -- after about six months to a year they all end up giving us good results. So the bottom line, the take-home message is that you can get a good result with any of those choices.
The difference between autograft and allograft is pretty much a personal choice. When you take the tissue from your own knee, there's obviously some insult or morbidity to where you're taking the graft from -- the donor site morbidity is what we term that -- but you can imagine that you'd have to let that hamstring or that patellar tendon site where you've harvested from heal; it's an injury. Like the hamstring -- if you take the hamstring tendon, that's like a hamstring tear and you've got to let that heal and recover.
So it does affect you in the first six or eight weeks after the surgery, in that you have a little bit more pain and swelling, maybe some bleeding, you have to let that heal before you start working on your hamstrings- or your quadriceps-strengthening -- when you take it from your own body. The benefit of taking it from your own body is that it is your own tissue. You don't have to worry about rejection or infection or any of those other potential complications.
Speaking of that, if you do use or choose to use tissue from a tissue bank or a donor, then you obviously eliminate the donor site morbidity of your own body. In other words, you don't have to wait for the hamstring or the patellar tendon to heal. So there's a little less pain, a little less swelling, a little quicker recovery in those first six weeks.
The downside to using donor tissue is the potential, the biggest downside is the potential for transmitting disease or infection from the donor.
Now, most reputable tissue banks will screen incredibly well and ultimately carefully to prevent the tissues being infected or transmitting disease. And the way we now test these tissues, they've estimated the risk of transmitting a disease at less than one in a million. In other words, there's a greater chance of getting killed in a car accident than developing a disease or an infection from donor tissue. But again, it can happen, so there's some, always some reluctance in certain individuals. Again, it's a personal thing in terms of using tissue from a donor.
But those are the two main choices you have when deciding on which type of tissue to use rebuilding your ACL.