Iliotibial Band Syndrome

Iliotibial band syndrome (ITBS) is an overuse condition causing lateral knee pain at the lateral femoral epicondyle, and is the most common lateral knee injury in runners.

Its incidence in runners is estimated at 5 to 14%, and it also affects cyclists, rowers and military recruits. Pain is provoked by repetitive knee flexion and extension through about 20 to 30° of flexion. Current thinking favours compression of an innervated fat pad beneath the band rather than friction. It is a clinical diagnosis, and most cases settle over weeks to months with load modification and hip-focused rehabilitation.

The iliotibial band (ITB) is a thickening of the fascia lata running from the iliac crest to Gerdy's tubercle on the anterolateral tibia. Proximally it receives fibres from tensor fasciae latae and gluteus maximus. Distally, the Kaplan fibres anchor it to the femur, so the band does not glide back and forth over the epicondyle as the friction model assumed.

Anatomical and MRI work (Fairclough et al.) supports a compression model. A richly innervated, vascular fat pad lies between the deep surface of the ITB and the lateral femoral epicondyle, and the ITB compresses it against the epicondyle at around 30° of knee flexion. Downhill running and longer strides increase the time spent in this zone.

Training error, such as a sudden increase in volume, downhill mileage or cambered surfaces, is a common precipitant. Hip mechanics are also implicated: some studies report greater hip adduction and knee internal rotation, and weaker hip abductors, in runners with ITBS, but the evidence is limited, mostly cross-sectional and may differ between men and women.