Illotibial band syndrome (ITBS) is the most common cause of knee pain in runners. The illio-tibial band (IT band) is a superficial thickening of tissue on the outside of the thigh, extending from the outside of the pelvis/hip region and inserting just below the knee. ITBS occurs when there is a constant rubbing and friction of the IT band on the outside of the knee. The main symptom of ITBS is sharp pain or burning on the outside aspect of the knee. The pain can also travel up the side of the thigh to the hip region.
Runners often note that they start out running pain free but develop symptoms after a reproducible time or distance, which can be made worse by running downhill. Early on, symptoms subside shortly after a run, but return with the next run. If ITBS progresses, pain can persist even during walking, particularly when the patient foes up or down stairs. ITBS tends to come and go but left untreated can be a nagging injury. Contributing factors include an increase in mileage, running on cambered surfaces, over-pronation, and hip abductor weakness.