Everything You Need to Know About the ACL Tears
Written by Julie Hubbard
Soccer players, and most athletes for that matter, often dread hearing the three letters A-C-L in direct succession. “It looks like you’ve torn your ACL.” Ugh. Those words can pretty much guarantee a bad day for anyone 100% of the time.
Let’s answer your burning questions about ACLs and tears:
What is the ACL? Why is the ACL important?
What happens when you tear your ACL?
How do you know if you’ve torn your ACL?
Should you get an ACL reconstruction?
But what is the ACL and why is it so important?
The anterior cruciate ligament, or ACL, is one of four major ligaments that stabilize the knee. A ligament is a soft tissue that connects two bones – in this case the tibia (or shin bone) and femur (or thigh bone). The ACL is located in the middle of the knee and forms an ‘X’ with the posterior cruciate ligament (PCL). It prevents anterior translation, or forward movement, of the shin bone relative to the thigh bone.
A torn ACL can occur when the ACL is suspect to too much force. This usually happens when an athlete is decelerating (slowing down), cutting/pivoting (changing direction), or landing from a jump. There is usually an audible “pop” and subsequent feeling of instability with walking, running, and/or going up or down stairs. Swelling is often delayed, and other symptoms like clicking, popping, locking, catching, or grinding can occur if there is damage to other adjacent structures like the meniscus.
Okay – so what’s the big deal about a torn ACL?
There are between 125,000 and 250,000 arthroscopic ACL reconstructions in the United States each year, with the majority of these patients falling under the age of 25 participating in high-school, collegiate, or recreational-level sports. Although not everyone elects to have an ACL reconstruction – these people are called ‘copers’ – it is largely accepted in the rehabilitation community that young athletes should have the ACL surgically repaired to ensure the stability of the knee and prevent future complications later on down the road.
Multiple studies have shown that tearing the ACL makes the knee much more susceptible to premature osteoarthritis later in life (ouch!). Not to mention, a torn ACL requires anywhere from 6 to 9 (and sometimes even 12) months of intensive knee rehabilitation, where athletes must first regain range of motion, re-learn how to walk, rebuild strength/endurance, and eventually be reintroduced to sport and other functional activities. (Spoiler alert: Even after extensive rehabilitation, approximately 1 in 5 patients suffer re-injury within 2 years.)
In addition to the physical toll, there are also financial and mental costs! An ACL reconstruction can range anywhere from $10,000 to $30,000, depending on the extent of damage within the knee joint. Luckily, insurance takes care of most of this, but you’re still left with a pretty hefty bill if you haven’t already met your yearly deductible. And don’t forget about your co-pays for physical therapy x number of times a week for x weeks. I won’t even get into the mental side of things. Just know that tearing your ACL is a huge buzz kill. I’ll save the sport psych for a later date.
Shockingly, almost two-thirds of all ACL tears occur without another player even touching you. These are called ‘non-contact’ injuries and happen when your body moves the wrong way. Female athletes are 4-8x more likely to demonstrate these faulty movements due to a number of factors. Let’s call these non-modifiable and modifiable risk factors. Non-modifiable risk factors are things that you cannot change or control. They include things like: joint laxity, hormone levels, femoral notch width, decreased ligament size, increased slope angle, and Q-angle. These are biological and anatomical things that we can not change.
Modifiable variables are things that you can control.
[Paging Hubbsy!] This is where I come in
Length-strength muscle imbalances can predispose the ACL to injury. Meaning, if certain muscles are tight and other muscles are weak, your knee will move into positions that your ACL does not like. This typically includes the knee caving inward (called “valgus” in the rehab community) and usually occurs when the knee is at almost-full extension. Add a little bit of twisting or rotation to the equation and you’ve got yourself the perfect storm. To prevent this, you must have adequate hip flexor, adductor (groin), and gastrocnemius (calf) flexibility, as well as appropriate core, gluteal (hip), and hamstring strength. Female athletes typically exhibit quadriceps dominance after puberty, meaning that the quads are often much stronger than and activate before the hamstrings. When this happens, the quads can expose the knee to higher-than-normal shear forces and translate that tibia forward on the femur. Typical hamstrings to quadriceps ratios are anywhere from 0.5 to 0.8. It has been proven that as this ratio approaches 1.0 (or the hamstrings get stronger), the risk of ACL injury goes down.
Not only must you possess adequate strength – You must also be able to activate and utilize this strength when you are moving functionally. This is where the concept of motor control and proprioception (or body position sense) comes into play. Motor control refers to the communication between your brain and your muscles. Your nervous system must be able to coordinate your muscles and limbs to achieve the desired movement or set of actions – like accelerating, decelerating, cutting, pivoting, jumping, or landing. You can be the strongest person in the world, but if your brain does not know where your knee is in space, or if it does not tell your muscles to fire in the correct sequence, you will overload that ACL and end up on the sidelines. No bueno.
What can you do to prevent a torn ACL?
Now that I’ve got your attention, let’s talk about what you can do to avoid a torn ACL. You can work on the flexibility of the aforementioned muscles and strengthen your core and posterior chain. Seek out a medical professional for neuromuscular re-education, or ask them to teach you how to move properly. Better yet, if you are in the Greater Boston area, contact us and we will teach you how to move properly.
While statistics vary from source to source, research has shown that ACL injury prevention programs can reduce the risk of injury as much as 75%, if executed properly. These programs often include strength training, motor learning, balance/proprioceptive training, and plyometrics. The most important part of these programs is the quality of exercise repetitions. Athletes must not only complete the prescribed exercises, but they must complete the exercises properly. What good is an injury prevention program if you practice jumping the wrong way three times a week? This is why you should seek out a trained medical professional or movement specialist reduce your risk of ACL injury. While the risk of tearing the ACL cannot be completely eliminated, it can certainly be reduced. Not only can players learn to move in a safe and efficient manner, but they will also consequently enhance their performance by getting better, faster, quicker, and stronger.
There are a number of resources available to coaches, parents, and sports practitioners who wish to participate in and/or implement ACL prevention programs in their communities. Below, I’ve included links to three of the best and statistically supported programs currently in existence. They include the PEP, the Sportsmetric Program, and the KIPP. Check them out below and let me know what you think!
Santa Monica Sports Medicine Foundation’s Prevent Injury and Enhance Performance Program (PEP): http://www.aclstudygroup.com/pdf/pep-program.pdf
Cincinnati Sports Medicine Research and Education Foundation’s Sportsmetric ACL Prevention Program: http://sportsmetrics.org/
Lurie Children’s Hospital of Chicago’s Knee Injury Prevention Program (KIPP): http://kipp.instituteforsportsmedicine.org
Thanks for reading and until next time, be well!
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If you are coming back from an ACL injury, we are here to help! Contact us to get back to being stronger and more athletic than before you were injured.
