The ITB is a lateral thickening of the fascia latae of the thigh that forms from the coalescence of fascial investments from the tensor fascia latae and gluteus medius and minimus muscles. This forms a tight connective tissue band that inserts on Gerdy's tubercle of the anterior proximal tibia. Tightness of the ITB is implicated in several pain syndromes, but the ITB syndrome refers specifically to friction between the ITB and the lateral femoral condyle as it rubs back and forth when the knee flexes and extends. Risk factors for ITB syn-drome include repetitive knee flexion and extension, making it the most common cause of lateral knee pain in runners and cyclists. Pain over the lateral aspect of the knee initially occurs only during exercise, but with progression can be present at rest as well. Aggravating factors include running outside, downhill, or attempts at lengthening strides.  

The Noble compression test consists of reproduction of pain upon palpation of the ITB over the lateral femoral condyle and flexing the knee to 30. 

MRI can confirm the diagnosis of ITB syndrome. The differential diagnosis includes other common causes of lateral knee pain in athletes, including lateral meniscus pathology, lateral compartment DJD, or tendinopathy of the biceps femoris.  Typical treatments include activity modifications, physical therapy, and injections.