ACL Injury


What is an ACL injury?

The anterior cruciate ligament (ACL) is one of the major ligaments in the center of the knee. It connects the thighbone (femur) to the shinbone (tibia) and is vital to the stability of the knee joint. The ACL protects the femur from sliding forward on the tibia and limits how far it can rotate. It also helps to prevent hyperextension of the knee.

Sprains are graded I to III depending on the amount of structural damage:

  • grade I sprain: pain, but little damage of the ACL
  • grade II sprain: higher damage of the ACL with mild looseness of the joint
  • grade III sprain: complete rupture of the ACL with instability symptoms

How can it occur?

A forced twisting motion, a sudden stop, or hyperextension of the knee can result in an ACL injury. For dancers, this most often occurs when landing a jump on a turned out leg, with the knees angling inwards. If the knee is hit from the side, the medial meniscus and medial collateral ligament (MCL) often also tear, along with the ACL. This injury is also known as “unhappy triad.” Muscle dysfunction can seriously affect leg alignment and stabilization and is an important contributing factor to knee injury and overuse issues concerning the lower extremities. Muscle overuse often occurs when the body fails to compensate for existing muscle dysbalance. Muscle dysbalances are very common and naturally occur as the body adapts to specific training demands over time. As long as compensation is effective – or, in other words, as long as the dysbalance is well managed by the body – this need not cause any problems. However, with high training loads, insufficient rest or after a minor injury, the body may struggle to compensate, leading to muscle dysfunction in the various muscle groups involved in the compensation. This is why symptoms may simultaneously occur in different parts of the body in an overuse situation.
The psoas muscle is probably the most important muscle involved with dance injuries. Psoas dysfunction leads to tightness of the rectus femoris muscle (a part of the quadriceps) and causes anterior rotation of the pelvic bone (ilium/innominate). As a result, the hamstrings on the back of the thigh will be loaded and a dysbalance between the hamstrings and the quadriceps will build up. This will be seriously affected active knee stabilization and the risk of an ACL injury will raise.

What are the typical symptoms of an ACL injury?

Typically you may experience a popping sensation inside the knee at the moment of the injury. The knee will then swell up over the next few hours. Injuries of the ACL are usually very painful and you may have problems to stretch and bend your knee and to fully weight-bare it.
Instability symptoms are present in grade II and III lesions. You may feel your knee giving way to the front or being instable in rotation.

How can an anterior cruciate ligament sprain be diagnosed?

Your doctor will examine your knee and perform some specific tests to find out if an ACL injury is present. During examination it is very important to relax your knee and thigh muscles as far as pain allows. If an ACL injury is suspected, an MRI scan is usually necessary to verify the lesion and determine its type and grade. It may also help to detect other knee lesions like cartilage or meniscus lesions.


This MRI scan shows a recently torn ACL. Fluids appear white in this picture. Compared to what an ACL normally looks like, this ACL appears significantly thicker and there is liquid inside of it. This is due to a bleeding that has occurred with the tear.

What treatment options are there?

If you had a knee injury, you should take a break from your ballet training immediately. Ignoring the pain can have serious consequences, as the situation will become increasingly complicated the longer you train with pain.
The RICE concept (rest, ice, compression and elevation) is an easy guideline that can be used to initially treat acute knee injuries. Please read my “First Aid” post to obtain some background information that you will need to adapt this concept successfully and learn about the use of painkillers.
Depending on the grade of the ACL injury, there are different treatment options. You may consider having surgical ACL reconstruction. However, a golden rule of ACL surgery says that operation of a torn ACL should either be performed within the first 24hours or after 6 weeks at the earliest.
In most cases you will have ample time to make a well-reflected decision regarding the necessity of an operation. However, there are some cases were a surgical therapy is mandatory. This is mostly the case if other structures as the meniscus or the joint cartilage are hurt. Injured knees that don’t have instability symptoms after a minimum of 6 weeks of intense rehabilitation probably have a chance to remain stable without operation. A torn ACL usually cannot be easily sewn together. An ACL reconstruction is performed by taking ligaments or tendons from other parts of the body and transplanting them to the site of the torn ACL. Rehabilitation after ACL reconstruction will usually last between 9 and 12 months after surgery.
In order to handle a given overuse situation in the course of rehabilitation, its underlying causes – namely muscle dysfunction and muscle dysbalance – have to be addressed specifically. Muscle dysfunction can appear as muscle tightness (contraction) or weakness (inhibition) and the muscles affected have to be treated accordingly in the rehabilitation process. Some muscles will have to be stretched whereas others will rather have to be strengthened. A well-suited training program including corrective exercises as well as a general strengthening and endurance routine is the most effective way to deal with most overuse situations.
Manual medicine and especially deep myofascial release treatment is recommended to address present joint and myofascial dysfunction.
Ensure that you follow your specific training routine after the rehabilitation is finished. Myofascial rollers (Blackroll, Triggerpoint Roll, etc.) as well as Lacrosse balls and resistance bands are easy to use in the studio and will help you remain balanced in the long run.

Next steps

You had a knee accident and suspect a problem with your ACL? These are the next steps:

  • See a doctor

Dancers seek help from various different kinds of therapists, many of whom may employ treatments that are outside of mainstream medicine. Before considering the use of such alternative medicine, you should see a doctor for an evaluation and diagnosis. If surgery is recommended, finding a doctor who is familiar with dancers’ knees is sometimes challenging and you may want to see different specialists. A good place to start is to ask your friends and fellow dancers for the names of their favorite doctors.

  • Start working on the underlying  problems after an operation

As far as rehabilitation allows, there is a lot that you can do to work on the problems that may have contributed to the accident. Ultimately, it often comes down to addressing the same fundamental issues. Here are some useful exercises that I recommend to my patients (most of them can be performed wearing a brace):

Flexibility training: Rectus femoris release, Hamstrings release, Adduktor release, ITB release, Psoas stretch, Lumbar spine releasePiriformis release,

Strength training: Core training – resistance band workout, Core training – Abs crunches, “The clamshell” – Piriformis training, “The monster walk” – Piriformis training

Please refer to your doctor to confirm that the exercises you choose to do are suited to your individual problem, and obtain supervision from a professional trainer to ensure that you are performing them correctly.

  • Talk to your ballet master or dance teacher

Technical issues and faulty dance technique are important predisposing factors of overuse and injury in dancers. Amending dance techniques often plays a crucial role in the treatment and prevention of overuse and injury and you should not hesitate to address any issues, if necessary.



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