Iliotibial band syndrome (ITBS) is an overuse injury. It happens in the soft tissues in the lower thigh, near the outside of the knee. The iliotibial band (ITB) is a thick band of fibrous tissue. It runs from the hip down the outside of the thigh and attaches to the tibia. The tibia is the large bone of the lower leg.

Treatment depends on the severity of the injury.

Tendons of the Lateral Knee
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ITBS is caused by repetitive friction or rubbing of the iliotibial band against the bone on the outer side of the knee. This excessive rubbing can irritate the ITB itself and/or the tissue underneath.

Causes of the excessive friction include:

  • Structural abnormalities, such as a short, tight IT band
  • Problems related to the foot, ankle, or hip
  • Opposing muscle imbalances, such as the quadriceps stronger than hamstrings
  • A very prominent lateral femoral epicondyle, the bony structure on the outer side of the knee
  • Inward rotation of the leg
  • Angle where knee flexes
  • Legs of different lengths
  • Bowlegs