The iliotibial band tract or IT band (ITB) is a longitudinal fibrous sheath that runs along the lateral thigh and serves as an important structure involved in lower extremity motion. The ITB is also sometimes known as Maissiat's band. The ITB spans the lower extremity on its lateral aspect before inserting on Gerdy's tubercle on the proximal/lateral tibia.
Proximally in the thigh, the ITB receives fascial contributions from the deep fascia of the thigh, gluteus maximus, and tensor fascia lata (TFL). The TFL is the deep investing fascia of the thigh, encompassing the muscles of the hip and lower extremity around this region. Distally, the ITB becomes a distinct soft tissue layer of the lateral knee.
There are multiple clinical conditions that can present secondary to a spectrum of ITB dysfunction and many of these manifest in physical laborers to recreational or high-level professional athletes. Moreover, these conditions will vary depending on the specific anatomic location of the dysfunction. For example, proximally based ITB conditions include external snapping hip syndrome, which occurs secondary to ITB friction as these fibers rub (or "snap") over the greater trochanter of the femur Distally, ITB pathology most commonly manifests as some form of lateral-based knee pain (commonly ITB syndrome, or ITBS). Athletes affected are often involved in sports heavily reliant on peak lower extremity function and performers, such as runners, skaters, or cyclists.
Regardless of the ITB condition, most patients experience complete resolution of symptoms following nonoperative management modalities alone. However, surgical consideration is a potential option for chronic, recurrent, or recalcitrant cases that continue to persist despite exhausting of all nonoperative management options after several months.