Iliotibial Band Syndrome (ITBS)

Iliotibial Band Syndrome (ITBS) is a painful inflammation of the iliotibial band, a thick, tendon-like portion of a muscle that travels from the hip down the outer side of the thigh to the knee. ITBS results in pain, aggravated by activity, that is usually felt on the outer side of the knee. 

Iliotibial band syndrome (ITBS) is one of several conditions of the kneecap, or patella, that is commonly referred to as runner's knee.