Iliotibial band syndrome (ITB) is a common running injury. The ITB runs along the lateral or outside aspect of the thigh and is an important structure that stabilizes the outside of the knee as it flexes and extend. The pathway of ITB is caused by excessive friction and impingement on the lateral femoral epicondyle at approximately 20-30° of knee flexion.
Factors such as leg length differences and increased prominence of the lateral epicondyles have also been noted as possible non-modifiable factors associated with ITB, and factors such as reduced flexibility, excessive pronation, high weekly mileage; time spent walking or running on a track; interval training and muscle weakness of the hip abductor muscles may also be associated with ITB.
Typically a diagnosis is based on the case history and physical examination is local tenderness of the lateral knee inferior to the epicondyle and superior to the joint line. The Ober test for distensibility of the iliotibial band is also frequently a measurement of interest, though in some cases magnetic resonance imaging or computed tomography might be indicated to rule out another disorder in the region.