What is a Kneecap subluxation?
The kneecap (patella) slides on the thighbone (femur) in a bony channel called the trochlear groove. This guides the kneecap as the knee flexes and extends. Movement of the patella is highly influenced by the tension of the quadriceps. Instability of the patella, combined with muscle dysfunction of the quadriceps, can cause the patella to be pulled to the outside of the trochlear groove and to eventually slip over its edge. This is called a patellar subluxation.
The altered position of the patella in the trochlear groove, and recurrent subluxations, will put severe stress on the cartilage and may cause cartilage damage over time. It may also cause creeping sounds (crepitations) and pain. A traumatic displacement of the patella to the outside of the knee is called a patella dislocation. This is an acute injury and should not be confused with patellar subluxation.
How can it occur?
A traumatic displacement of the patella is often the initial cause for chronic instability of the patella and patellar subluxation. Certain anatomical abnormalities contribute to such posttraumatic instability. They include:
- patella alta: the kneecap is positioned higher in the leg than usual
- genu valgum or “knocked knee”: knees angle in and touch one another when the legs are straightened.
- trochlear dysplasia: underdevelopment of the outer (lateral) femoral condyle
Muscle dysfunction of the quadriceps plays an important role with patellar subluxation, as the position of the patella is directly influenced by the tension of the four heads of the quadriceps. Muscle dysfunction can appear as muscle tightness (contraction) or weakness (inhibition). Typically, the outside muscles of the quadriceps (vastus lateralis and rectus femoris) will be tight, whereas the vastus medialis muscle on the inside will be weak in an overuse situation. As a result, the patella will be pulled to the outside of the trochlear groove and might possibly slip over its edge.
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.
What are the typical symptoms of a Kneecap subluxation?
Patellar subluxation is often not painful and may only be noticed by a clicking of the knee with certain movements. Stronger symptoms may arise as leg stabilization gets worse and muscle dysfunction advances. They include pain with weight-bared flexion of the knee, swelling and crepitation – a creepy sound that occurs behind the kneecap.
How can Kneecap subluxation be diagnosed?
Your doctor will examine your knee and review your symptoms as well as your current training activities. He will especially check for pain around the patella and may use specific tests that provoke a subluxation. He will also put a focus on joint range of motion, leg alignment and general knee stability. Correct diagnosis of this issue demands a thorough functional clinical examination, including specific tests to identify joint and muscle dysfunction. Finding out the exact causes of patellar subluxation is sometimes challenging and your doctor may ask a specialist in manual medicine for his opinion. X-rays may be ordered to find out about anatomical abnormalities that contribute to the patellar instability. An MRI scan may reveal structural changes of the patellar cartilage in chronic or very acute cases.
This X-ray shows both knees in a flexed position. You can see both kneecaps (labeled patella) above the trochlear groove, the boney channel they glide in. Both kneecaps are displaced to the side – one a bit more than the other.
What are the treatment options?
If you have severe or constant knee pain, 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 as well as overuse 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.
In order to handle a given overuse situation successfully, its underlying causes – namely muscle dysfunction and muscle dysbalance – have to be addressed specifically in the rehabilitation process. 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. Restriction of the fascia plays a key role in all overuse issues and can be addressed effectively with manual medicine.
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.
Surgery may be recommended if you have severe pain or instability problems and non-operative treatment has failed to improve the situation. There are different surgical methods to address patellar instability. Your doctor and orthopedic surgeon should help you choose the best option for you.
Do you think that you might have an instability problem of your kneecap and want to have it sorted out? 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.
Finding a doctor who is familiar with the specific medical issues faced by dancers is often challenging and you may need to see several different specialists in order to get a full picture of your diagnosis. A good place to start is to ask your friends and fellow dancers for the names of their favorite doctors.
- Find a specialist in manual medicine
Doctors who specialize in manual medicine practice a whole-body approach. They will try to identify and specifically treat the underlying causes of your problem, rather than just the localized symptoms. This approach is important in addressing all aspects of the often very complex overuse problems that dancers experience. A specialist in manual medicine will perform a functional examination on every part of your body and will treat you according to these thorough findings.
To find a physician who specializes in this field, search for “Manual Medicine”, “Osteopathic Manipulative Medicine” or “Osteopathic Physician” on the internet.
- Start working on your problem
There is a lot that you can do to work on your problem after a proper diagnosis has been set. Ultimately, it often comes down to addressing the same fundamental issues. Here are some useful exercises that I recommend to my patients:
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.