Iliotibial Band Syndrome
Iliotibial band syndrome is an overuse injury well recognized as a common cause of lateral knee pain. It is particularly common in runners and cyclists, though it also occurs in weightlifters, skiers and soccer players. The incidence is reported to be as high as 12% of all running-related overuse injuries.
The iliotibial band (ITB) is a thickening of soft tissue that envelopes the lateral or outer portion of the thigh. The iliotibial band begins as a muscle near the top of the hip known as the tensor fascia latae (TFL). Other muscles that insert into the upper portion of this band are gluteus maximus and gluteus medius muscles. As the ITB courses towards the lateral portion of the knee, it inserts into the tibia in an area known as Gerdy’s tubercle. The function of the ITB is to assist in stabilization of the hip and knee. The function of the muscles inserting into the ITB are to abduct the leg. The ITB does not have an insertion that offers a favorable mechanical advantage. In fact, it is at a considerable disadvantage for the purpose of hip and leg abduction activity. Therefore when the hip abductors are weak, the tensor fascia lata must contract harder and over a longer period of time thus straining the ITB.
The diagnosis of iliotibial band syndrome is initially based on clinical examination where patients typically present with tenderness over the lateral femoral epicondyle and report a sharp, burning pain when there is pressure over the lateral epicondyle of the femur during knee flexion and extension. The pain is particularly acute when the knee is at 30° of flexion.
Symptoms ITB syndrome include pain or aching on the outer side of the knee. This usually happens in the middle or at the end of a run. A concomitant problem may occur at the hip called greater trochanteric bursitis. During flexion and extension of the knee the iliotibial band has historically been thought to rub over the femoral condyle creating irritation. Iliotibial band syndrome, in most cases, does NOT seem to be a friction syndrome with a “popping” of the tendon over the femoral epicondyle. Some research suggests that the ITB is firmly attached to the femur and is not anatomically capable of moving forward and backwards over the lateral epicondyle of the femur. Recent cadaver and MRI studies have failed to document the expected evidence for friction or for a primary anatomical bursa. Most runners do not report a “popping” feeling. Instead, there is compression in this region that most often affects the fat tissue overlying the femoral epicondyle.
Some factors that may contribute to this syndrome include genu varum (bow legs), excessive pronation of the foot, leg length discrepancy, and running on a crowned surface. Over the past few years an association with weak gluteus medius musculature has been found in many runners with ITB syndrome. The weakness of the gluteal muscles causes more tension to develop in the iliotibial band as the muscles inserting into it have to assist in keeping the hips level. Cyclists also develop iliotibial band syndrome from overuse. Circular track running may also contribute to iliotibial band syndrome, since it stresses the body in a manner similar to that occurring when running on crowned surfaces or in those athletes that present with true leg length differences. Changes in training may also contribute to the development of iliotibial band syndrome. It is always important to examine your training regimen and see what alterations have recently occurred. A rapid increase in training volume, distance, frequency, and intensity often precedes the development of this injury.