Iliotibial band syndrome (ITBS) is a common cause of pain in the outer (lateral) side of the knee. ITBS is also a common overuse injury in runners. In order to better understand ITBS it is important to understand the anatomy and function of the knee. Please review the section on knee anatomy before reviewing this section.
The knee joint is made up of four bones, which are connected by muscles, ligaments, and tendons. The femur is the large bone in the thigh. The tibia is the large shinbone. The fibula is the smaller shinbone, located next to the tibia. The patella, otherwise known as the kneecap, is the small bone in the front of the knee. It slides up and down in a groove in the femur (the femoral groove) as the knee bends and straightens.
What is the iliotibial band?
The iliotibial band is a belt-like band of tissue that runs from a muscle on the outer side of the hip, the tensor fascia lata, down the outer side of the thigh and attaches to the outer side of the patella and the tibia. Other muscles of the hip also attach to the iliotibial band and together with the tensor fascia lata control outward hip movement (abduction). The iliotibial band also provides stability to the lateral side of the knee.
A bursa (pl. bursae) is a small fluid filled sac that decreases the friction between two tissues. Bursae also protect bony structures. There are many different bursae around the knee. There is a bursa that protects the iliotibial band from the underlying femur. Normally, a bursa has very little fluid in it but if it becomes irritated it can fill with fluid and become painful.
The end of the femur has two large projections called epicondyles. When the knee is fully straight (extended) the iliotibial band lies in front of the lateral epicondyle of the femur. As the knee bends (flexes), the iliotibial band slips over the lateral epicondyle and ends up behind it. Friction occurs where the iliotibial band passes over the lateral femoral condyle. This friction can result in inflammation of the bursa that separates the iliotibial band from the underlying bone, or the iliotibial band itself.
What causes iliotibial band syndrome?
ITBS is usually the result of overuse or overtraining. ITBS is found predominantly in runners and is often associated with changes in training such as a sudden increase in distance or intensity. Running on uneven surfaces such as the shoulder of the road may also cause ITBS, most commonly in the “downhill” leg. Other predisposing factors include prominent lateral femoral condyles or tight iliotibial bands.
As mentioned above, the pain from ITBS is felt on the lateral aspect of the knee. The pain may also radiate up the lateral aspect of the thigh or around to the front of the knee. The pain is usually made worse by repetitive flexion and extension movements of the knee. Initially, the pain may only be felt during a run. If training continues, pain may be felt even at rest.
How do you diagnose iliotibial band syndrome?
On examination of the knee the iliotibial band is usually tight. There is often tenderness of the iliotibial band where it passes over the lateral femoral condyle. When pressure is applied to the lateral femoral condyle and the knee is repetitively flexed and extended the pain that is felt during training can often be reproduced. X-rays are usually normal.
What is the treatment for iliotibial band syndrome?
Treatment of ITBS may include relative rest, icing, medications to reduce inflammation and pain, stretching, and strengthening exercises. Doctors and physiotherapists trained in treating this type of overuse injury can outline a treatment plan specific to each individual.
Please visit the links section for additional information on ITBS. Links have been provided to other websites as well as online medical journals. Other knee injury topics can also be accessed.