The knee is one of the most relied upon joints of the human body and is subjected to a great deal of force every day. During a simple activity like walking, the amount of force placed upon this joint is equal to anywhere from one-third to one-half an individual's body weight. When a person is climbing stairs the force placed upon the joint is equivalent to 3 times the individual's body weight, and when squatting, the knee must manage a force equal to 7 times the individual's body weight. When considering these facts, it is easy to understand that there must be a great amount of stress placed upon the knee in all kinds of dance. When the knee joint is functioning correctly, it is usually able to cope with this stress, however, when something is misaligned, and the knee joint is not functioning efficiently, the stress can be detrimental.
Patellar femoral syndrome is a chronic condition in which the patella, or knee cap, is not correctly aligned. The patella is a triangular shaped bone that lies on top of the femur, or thigh bone. There is a groove in the femur which allows the patella to slide back and forth as the knee bends and extends. When the patella is not in alignment, it does not fit well into this groove, and the friction of the patella against the femur begins to wear away the cartilage found in the joint.
When the knee joint is at rest, the patella is held in place by the capsule surrounding the joint, the ligaments on either side of the patella (the retinaculum), and the patellofemoral ligament, which connects the femur to the patella.
When the knee is actively bending or extending, the joint's stability is provided by the quadriceps (the four muscles located on the front of the thigh), the vastus medialis (which is a muscle that is found on the inner side of the thigh), the vastus lateralis (which is a muscle that runs along the outside of the thigh), and the iliotibial band, which runs from the gluteal muscle of the buttocks down the outside of the thigh.
Dancers with patellar femoral syndrome will experience pain behind and around the kneecap during activities that require the knee to bend like squatting, jumping or climbing stairs. Occasionally, the dancer will also experience the knee buckling, or "giving way" when walking and may also complain of stiffness in the knee after sitting for a while.
Any dancer experiencing these symptoms should rest the joint and use ice and anti-inflammatories to control the discomfort. The dancer should also contact a sports or dance medicine doctor to get a complete diagnosis. In most cases, once the cause is determined, physical therapy can help alleviate the symptoms and help realign the kneecap.
Since an ounce of prevention is worth a pound of cure, my next post will focus upon the causes of patellar femoral syndrome and how to prevent this condition from occurring.