Iliotibial Band Syndrome (ITBS) is a frequent cause of pain on the outside of the knee, particularly affecting individuals who participate in endurance activities like running and cycling. This condition is classified as an overuse injury, resulting from repetitive movement of the iliotibial band over the lateral femoral epicondyle, which is the bony prominence on the side of the knee. The friction or compression that occurs during this repetitive motion leads to irritation and inflammation in the underlying fat and connective tissue.
The Standard: Clinical Diagnosis of ITBS
Iliotibial Band Syndrome is primarily diagnosed through a careful review of the patient’s history and a targeted physical examination. A healthcare provider will typically ask about the onset of the pain, its location, and the activities that exacerbate it. Patients often report an insidious onset of pain localized near the lateral femoral epicondyle, which worsens with continued activity, especially downhill running or climbing stairs.
The physical examination focuses on identifying point tenderness and reproducing the patient’s pain through specific movements. Tenderness to palpation is typically found over the lateral femoral epicondyle, usually one to two centimeters above the joint line. Pain can often be elicited when the knee is moved through approximately 30 degrees of flexion, which is considered the “impingement zone” where the band makes contact with the bone.
Two common provocative tests are often used to isolate the iliotibial band as the source of discomfort. The Noble compression test involves applying pressure over the lateral epicondyle while the knee is moved from flexion to extension, which frequently reproduces the sharp pain. The Ober test assesses the flexibility of the iliotibial band, and resistance to hip adduction during this test can indicate tightness of the band, further supporting the diagnosis of ITBS.
What MRI Can Reveal About the Iliotibial Band
The answer to whether ITBS shows up on a Magnetic Resonance Imaging (MRI) scan is yes, but the findings correlate with inflammation rather than a structural tear. An MRI can visualize specific signs of soft tissue irritation that accompany the syndrome.
The most characteristic finding is the presence of an ill-defined area of high signal intensity on T2-weighted images within the fatty tissue deep to the iliotibial band. This increased signal corresponds to edema, or fluid accumulation, indicating inflammation in the fat pad that lies between the band and the lateral femoral condyle.
In some cases, the MRI may show a localized, circumscribed fluid collection, which suggests the formation of an adventitious bursa due to chronic friction. In chronic or long-standing cases of ITBS, the iliotibial band itself may also appear thickened on the MRI scan.
When Imaging is Necessary to Rule Out Other Conditions
While ITBS is commonly diagnosed clinically, imaging like MRI becomes necessary when the diagnosis is uncertain or when symptoms persist despite conservative treatment. The primary function of ordering an MRI in a suspected ITBS case is to perform a robust differential diagnosis. Many other pathologies can cause pain on the lateral side of the knee, and advanced imaging helps to exclude these alternative causes.
Conditions such as lateral meniscal tears, lateral collateral ligament sprains, and stress fractures can present with similar pain patterns to ITBS. An MRI provides detailed images of the bone, cartilage, and other soft tissues, allowing physicians to confirm that the symptoms are not due to an underlying structural injury. Because MRI scans are costly and time-consuming, they are generally reserved for patients who present with atypical symptoms or those who do not respond to a standard course of rest and physical therapy.