The iliotibial band is an important piece of the locomotion puzzle via the trigger mechanism and by providing a strong tensile force capacity and “free” energy to minimize the energy cost of locomotion (Bosch, 2006). It also often becomes a pain generator in runners and is perhaps the leading cause of lateral knee pain in this population.
The IT Band is a lateral thickening of the fascia lata that rises from the tensor fascia latae and gluteus maximus, courses down the side of the leg to lateral femoral condyle and ends at Gerdy’s tubercle at the anterio-lateral tibia. The pervasive belief in the manual and movement therapy community is that with flexion and extension of the knee, the IT band glides over the lateral femoral condyle repetitively ultimately leading to local swelling and sharp, burning pain upon movement in the sagittal plane. Some attribute this edema and pain to a bursitis.
Fairclough and colleagues, however, challenge this assertion in their 2006 paper in the Journal of Anatomy. The team examined the gross anatomy of 5 cadavers, performed MRI on 6 healthy volunteers, and 2 runners (an elite track athlete and a recreational marathoner) presenting with IT Band pain.
The findings were fairly consistent across the board demonstrating a strong linkage of dense fibrous connective tissue of the distal end of each band anchoring firmly to the lateral femoral condyle (or just proximal in a fanned pattern) as well as it being continuous with the lateral intermuscular septum and attached to the linea aspera of the femur that was confirmed either in MRI imaging or via dissection. The authors took this finding as evidence that the freedom of movement likely is not available to create “friction” over the lateral condyle.
Equally consistent in the study, subjects presented with highly vascularized and innervated adipose tissue under the distal IT band in the area most commonly labeled painful in ITB syndrome and in both pathological subjects. The adipose contained a significant amount of Pacinian corpuscles.
Images of the knee flexed to 30 degrees demonstrated that the IT band approximates the femur and compresses the fatty tissue beneath it. This is likely due to the accessory joint motion of tibial internal rotation that occurs naturally with knee flexion placing tension on the IT band. It also plays to better understanding of how subtalar abnormalities and atypical hip and knee kinetics associated with IT band pathologies serve to perpetuate pain (Ferber, 2010; Geraci, 2005).
The authors suggest that pain and edema are a result of repetitive impingement or compression of the highly vascularized and innervated adipose citing increased signal deep to the IT band in both pathological subjects, which is evidence of fatty edema.
Research by Benjamin et al (2004) demonstrated that the presence of adipose tissue at entheses is common and anatomically normal. In addition, Benjamin notes that the high quantities of innervation and Pacinian corpuscles add to the proprioception of the joint and can be powerful pain generators.
Taking the available evidence further, it may be best to refer to IT Band “Friction Syndrome” as an “enthesopathy” or at least not a “friction syndrome” (Benjamin, 2006).