iliotibial band syndrome

iliotibial band syndrome (ITBS), inflammation of the band of fibrous tissue known as the iliotibial band (or tract), which extends from the ilium of the hip to the tibia (shinbone). Typically, iliotibial band syndrome (ITBS) results from overuse injury, seen most commonly in distance runners and other athletes whose sports require a great degree of knee flexion. The condition has also been described in cyclists, soccer and tennis players, skiers, and even weightlifters (e.g., those doing power-lifting moves, such as squats). ITBS typically causes lateral knee pain that is insidious in onset. It is the most common cause of such knee pain in runners and accounts for approximately one-tenth of running-related injuries. Diagnosis can be relatively straightforward, but ITBS is often very frustrating to treat for both patients and clinicians.

Anatomy

The iliotibial band (ITB or IT band) is a tough, fibrous band of deep fascia (tissue that sheathes muscles and muscle groups) that is extremely strong and thick. It extends from the curve in the upper border of the ilium (the iliac crest) to the top of the tibia, the patella (kneecap), and the biceps femoris tendon (at the back of the thigh). The ITB, therefore, crosses two joints, the hip and the knee, and can be involved in pathology in both areas (e.g., the ITB is implicated in the development of some forms of “snapping hip” and in trochanteric bursitis).

The ITB’s primary function is to control and decelerate the adduction (inward movement) of the thigh on heel strike, as during running. The condition of ITBS is one of knee pain that results from excessive friction of the ITB over the lateral femoral epicondyle (a bony projection of the femur, or thighbone, on the outer side of the knee). As the knee flexes from full extension to about 30°, the ITB moves backward and traverses the femoral epicondyle. With repetitive flexion and the associated friction, irritation of the ITB and underlying soft tissues can ensue. Magnetic resonance imaging (MRI) and examination of the ITB during surgery have revealed both acute and chronic inflammation in patients.

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Risk factors for ITBS

Risk factors for the development of ITBS are often divided into those that are extrinsic to the patient and those that are intrinsic. Some of the extrinsic factors identified from observational studies include athletic techniques, such as track running and interval training, or characteristics of the athletic equipment used. Intrinsic factors may be anatomical issues (such as preexisting ITB tightness) or biomechanics (such as weakness of the knee extensor and hip abductor muscles). Some studies have also noted possible associations with the following: foot supination and compensatory pronation (insufficient inward roll of the foot, followed by abnormal inward roll), running on hills (especially downhill) or on beaches, cycling seat height, anatomical factors (e.g., bowleggedness [genu varus] and deformities of the tibia or varus), tight hamstring and quadriceps muscles, and limb-length discrepancies (ITBS typically develops in the shorter leg). Both extrinsic and intrinsic risk factors should be identified from the history and physical examination of the patient and can be targeted during treatment.

Presentation and diagnosis

During the taking of the patient history, the patient is usually unable to identify an obvious traumatic event. Lateral knee pain will have developed insidiously, and the athlete will typically complain of a sharp or burning pain approximately 2 to 3 cm (0.8 to 1.2 inches) proximal to the joint line that develops after a certain period of time or distance during a run or workout (the joint line sits within the joint, perpendicular to the long axis of the tibia). Runners often specifically notice a worsening of the condition associated with running downhill. As the condition progresses, pain can develop earlier during a workout or may even occur during walking, particularly down stairs.

Any possible contributing extrinsic factors should be identified during the physical examination, which should not only focus on the knee but also include an analysis of the entire kinetic chain (sequence of movements) on the affected side. As always with lower-extremity pathology, the clinician should ideally begin the examination with an inspection of gait for such signs as limb-length discrepancies and pronation or supination of the foot. On examination of the knee, there should be no joint-line tenderness or any significant effusion in isolated ITBS. Normal range of motion should be preserved. Palpation of the ITB, particularly over the lateral femoral epicondyle, may elicit pain. There may be localized swelling in the same area. Further palpation may elicit trigger points throughout the ITB as well as in the vastus lateralis (the largest of the quadriceps muscles), and the distal ITB is often noted to feel ropy and thick. The vastus medialis obliquus (a medial thigh muscle that helps stabilize the patella) is often relatively underdeveloped.

The diagnostic examination may include a number of specialized tests, such as the Ober test, which assesses ITB tightness, and the Noble compression, which determines the presence of pain as the knee approaches 30° of flexion. Plain X-ray films and MRI are occasionally necessary to evaluate other possible diagnoses. For ITBS itself, plain films would be expected to be negative, and MRI can show inflammatory changes in the area where the ITB crosses the lateral femoral epicondyle.

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Treatment

Conservative treatment for ITBS is usually successful, though the condition can recur, and patient compliance is crucial to success. The condition usually improves when the activity that provokes pain is avoided. Inflammation may be controlled with therapeutic dosages of nonsteroidal anti-inflammatory drugs and frequent icing. Occasionally, targeted steroid injections into the area of maximal pain are used. Some patients benefit from the correction of underlying limb-length discrepancies and of foot biomechanics with devices such as heel lifts or orthotics.

Physical therapy is routinely prescribed for ITBS. The goals of physical therapy include targeted increases in flexibility and strength associated with some of the intrinsic factors contributing to the syndrome. Stretching the ITB, the hamstrings, and the quadriceps is vitally important. Strengthening the hip abductors is also important.

Bicyclists can often benefit from a custom fit of their bike; often, lowering the seat slightly is sufficient to avoid critical impingement of the ITB against the femur, which occurs at about 30° of knee flexion. Adjusting the foot position on the cycle pedals may be helpful as well. Runners benefit from avoiding unidirectional running on banked surfaces (e.g., an indoor track, a beach, or a graded roadside) and from avoiding intervals, track workouts, and hills. Runners typically resume training at lower mileages than preinjury.

Surgery is rarely necessary. Success has been achieved with a surgical procedure in which a triangular piece of the ITB is resected from the area overlying the lateral femoral epicondyle when the knee is in the critical position of 30° flexion. In one study, 84 percent of surgically treated patients reported good to excellent results. As with many acute and chronic inflammatory conditions, however, surgery is considered the last resort.