Why do Partial ACL injuries occur?
Injuries to the ACL or Anterior Cruciate Ligament are becoming more and more common. The normal ACL is made up of two pieces, or bundles. If you injure only one of the bundles then you have a partial ACL tear, as opposed to a complete ACL tear. First we will explore what a partial ACL tear, then we’ll explore how partial ACL tears are treated.
What is the Anterior Cruciate Ligament
The anterior cruciate ligament – ACL –is one of the more vital and more commonly injured ligaments within our knee. Ligaments are generally small, but very tough structures which hold our bones together. The ACL allows us to twist, pivot and rapidly accelerate and decelerate. Most partial ACL injuries are non-contact in nature. With a partial ACL injury or complete ACL injury your knee might feel unstable with those same activities.
If you sustain a pivoting or twisting injury and feel a pop — there is a strong chance the you injured your ACL. Most people who have a partial or complete ACL tear will then notice significant swelling shortly after the injury.
The anterior cruciate ligament or ACL is the most commonly injured of the four major ligaments that exist within our knee. Most patients who have sustained an injury to their ACL will have enough discomfort that they will seek attention either in an emergency room or in orthopedists’ office fairly rapidly. Whether or not an ACL tear exists can be determined by a good physical exam. An MRI can be useful to confirm if a partial ACL tear or a complete ACL tear exists. The MRI will also show if any other structures in the knee were injured.
Complete ACL Tears:
A complete ACL tear involves the complete disruption of all of the ACL tissue that connected both the femur and tibia. You may simply possess discomfort, pain and swelling – – – or you may perceive that the knee is unstable and feels like it wants to buckle or give way. We have covered the treatment of complete ACL tears elsewhere within this website, and whether or not ACL surgery is always necessary.
For the recently injured, or those in the preparation phase for surgery I recently placed two ACL Surgery blog posts on this site.
- The first post will help you determine if ACL Surgery is necessary and it will assist you with questions you should ask your surgeon.
- The follow through post assists you with steps you should take before and after ACL surgery to minimize the risks of complications and improve your overall results following an ACL reconstruction.
Partial ACL Tears: Stable versus Unstable
A partial ACL tear involves an injury to only a portion of the ACL, or one of the bundles. Some partial ACL tears leave you with a stable, functional knee, and some partial tears will result in an unstable knee. With some partial ACL tears, the knee might feel like a knee with a complete ACL tear. Some patients who have a partial ACL tear will be able to return to their prior level of activity without complaints of buckling, instability or giving way. Unfortunately, a fair number of you will not be able to return to your prior level of activity because your knee feels unstable or loose.
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What I’m getting at is simply the fact that we should not look at your ACL tear as being “partial” or “complete”, we look at your KNEE as being “stable” or “unstable”. If you have a stable partial tear of your ACL, that means that you have torn a certain portion of your ACL fibers, however, you are still able to participate in sports without the feeling of the knee giving way or being unstable. On the other hand, If you possess an unstable partial tear of your ACL, that means that you have torn enough of your ACL fibers that your knee no longer feels stable. That means that you are at risk of further injury if you return to your prior level of sports participation. Furthermore, every time your knee buckles or gives way you run the risk of tearing other structures within the knee, such as the medial or lateral meniscus. If you sustain tears of either the medial or lateral meniscus, which are the shock absorbers within the knee, then you are at risk of developing osteoarthritis. You therefore want to eliminate or minimize the risk of buckling, instability or giving way. If you present with a partial ACL tear and complaints of instability we will likely talk about the possibility of undergoing an ACL reconstruction or possibly an ACL augmentation.
Partial ACL tear treatment options: If surgery is necessary:
The difference between an ACL reconstruction and an ACL augmentation is fairly simple. During the process of an ACL reconstruction we will reconstruct or replace the entire ruptured ligament. Anatomically, the ACL is composed of two separate bundles and a complete reconstruction will compensate for both of those bundles. In an ACL augmentation, you have only sustained a partial tear. That means that a portion of your ACL remains intact and might be normal. Many high volume ACL sports medicine orthopedic surgeons are capable of reconstructing only the torn portion of the partial ACL tear. This leaves the normal portion of the ACL alone. There are many advantages to an ACL partial tear augmentation over a full ACL reconstruction. While the discomfort, and the nature of the surgery is virtually identical – – – it is far more likely that someone who undergoes an augmentation will have a much more natural feeling knee when all is said and done. The reason for that is because the normal ACL has certain nerves within it. Those nerves give the brain certain feedback as to the position of the knee joint. It turns out that those nerve fibers are quite important. If we preserve the intact portion of your ACL, then we are preserving those nerve fibers and hopefully preserving the integrity of your knee in the long run.
Do have a question about the treatment of your partial ACL tear?
Have you been told that you require surgery for your partial ACL tear?
Click the blue button and come on in… I would be more than happy to help educate you about the alternatives available for treatment of your knee injury.