Welcome back to the dancer blog. For the past two weeks we’ve been discussing common
injuries that dancers experience. We’ve been focusing mostly on the ankle with our discussions on the Os Trigonum and Ankle Sprains but this week we’re moving up to the knee with a discussion on ACL tears. Just as before, we will be discussing the anatomy, mechanism of injury and contributing factors as well as what to do to prevent and care for such an injury.
ACL tears are the most common injury of the knee. This injury is most common amongst athletic populations, specifically those who regularly perform jumping, twisting and cutting movements. This is because of the role that the ACL plays within the anatomy of the knee joint.
Ok quick run down! The knee is composed of three bones; the Femur (thigh bone), the Tibia
(shin bone) and the Patella (knee cap). Together, these three bones create the knee joint. This joint is held together by six ligaments and two “shock absorbers.” First we have the ligaments running along the lateral side of the knee connecting the Femur and the Tibia. This is called the Lateral Collateral Ligament or LCL. Opposite the LCL on the medial side of the knee is the Medial collateral Ligament or MCL. Together these ligaments prevent inappropriate side to side movement of the Tibia on the Femur. In other words, it stops your knee from bending sideways.
In the middle of your knee and behind your Patella are your cruciate ligaments which cross over one another. Cruciate here meaning cross. You have the Anterior Cruciate Ligament, that’s your ACL, which starts at the back of your Femur and runs to the front of your Tibia as well as your Posterior Cruciate Ligament or PCL which runs from front of the Femur to the back of the Tibia. While the ACL prevents inappropriate forward motion of the Tibia on the Femur, the PCL prevents inappropriate backwards motion.
Additionally we have our medial and lateral menisci that act as shock absorbers for the knee
(more on that next week) and holding the Patella in place is your quadriceps tendon above
running from the quadriceps muscle to the Patella and the patellar tendon below connecting the patella with the front of the Tibia.
Together the MCL, LCL, PCL and ACL work to stabilize the knee joint. Among these, the ACL tends to take the majority of abuse with knee motion. This is why an ACL tear is the most common knee injury. Besides preventing inappropriate forward movement of the Tibia, the ACL also works to prevent inappropriate rotational movement. As dancers, rotation of the Tibia, specifically external rotation in “turn out” positions play a big role in how susceptible dancers are to this injury.
And actually, it plays in our favor. Or rather our training and how our training puts a heavy
emphasis on things like external rotation, jumping and balancing make dancers, as a
population, far more resilient to ACL tears than most other athletic populations. Just think of how much time dancers spend rehearsing the same movements over and over again. So much of our training is spent utilizing external rotation and transitioning into and out of jumps, both of which are risk factors for tearing your ACL. At the end of the day this approach to training makes us far less likely to experience an ACL tear. In fact, one study found that while the average occurrence of ACL tears amongst other athletic populations can be as high as 8%, elite dancers have been found to experience this injury closer to 0.2-0.4% of the time. That’s a big difference!
Another large contributing factor to this statistic is the fact that unlike many other athletic
populations, dance is generally choreographed. This means that there is a known and
predictable sequence of movements. Because of this, dancers know how to approach each
movement as they transition into and out of them. The vast majority of the time, a dancer will not be required to make a sudden and unexpected pivot movement. This means that they can approach otherwise risky movements with proper biomechanics. Compare this to a soccer player who has to make split second decisions all the time as they attempt to out maneuver other players on the field. Their actions are not pre-planned and as a result they have a significantly higher chance of executing twisting or pivoting motions incorrectly.
So dancers are pretty resilient when it comes to ACL tears. This does not mean however, that we don't still have risk factors. Quite the contrary, as dancers there are definitely a few things to be aware of if you’re looking to prevent such an injury from happening to you. Increased flexibility, strength imbalances between your quadriceps and hamstrings and poor biomechanics can very quickly put you at risk of tearing your ACL or any other knee ligament for that matter.
As I’ve talked about before, many dancers experience or outright work towards hyperflexibility. What I mean by this is flexibility that is either not balanced with proper strengthening exercises and control or in the case of true “hyperflexibility,” flexibility that is naturally beyond normal limits. A while ago I wrote a blog about how Oversplits Are Causing More Harm Than Good. This is one example of the sort of dysfunctional flexibility that can greatly increase a dancers risk for experiencing injuries such as ACL tears. Maintaining a balance between strength and flexibility will go a long way towards preventing this injury. Strength building exercises are going to be especially important for dancers who are naturally hyperflexible. I had a friend once who was double jointed in both of his knees. Throughout his career he tore his ACL on both legs and both menisci on the left leg because he never put the work in to balance his flexibility with strengthening and control exercises.
Ok so what should you do if you end up tearing your ACL. There are a few opinions out there on how to approach care and recovery from ACL tears. Now, I want to be very clear here that EVERY injury is unique and when it comes to injuries like a torn ACL there is no one size fits all. There are a lot of different factors that contribute to the decision making process including whether the tear is partial or complete as well as the overall goals of the patient. Treatment and recovery for serious injuries should always be a discussion between your healthcare provider and you. Especially when it comes to injuries that can have a big impact on the quality of life and career of a dancer. All the more reason that it’s important that you have a healthcare provider that truly understands your needs as a dancer.
That said, I do want to outline some of the options out there for ACL tears. Effectively there are two approaches to treating a torn ACL; surgical care and conservative care. Let’s start with surgical care. Surgery for a torn ACL involves taking portions of tendon from somewhere else in the body, usually the patellar tendon or part of one of the hamstring tendons, and using this to construct a new ACL. Alternatively, donor tissue, from a cadaver, can also be used to construct a new ACL. Surgery is followed up with rehabilitation programs to restore and maintain the range of motion in the joint as well as redevelop the strength and stability of the knee. Most surgeons and Medical Doctors will tell you that recovery from ACL surgery will take about 9 months. I want to emphasize that this is really only true for non-dancers. Due to the intense and highly mobile nature of dance, I tell dancers that they’re really looking at a year plus before they feel like their old selves.
Ok so what about the conservative care approach? Well it’s much the same as the surgical
option but you skip the surgery part. Conservative care for a torn ACL is an intense program of rehabilitation exercises to restore the knee’s range of motion and build up strength in the