Iliotibial band syndrome
Iliotibial band syndrome (ITBS), or iliotibial band friction syndrome, is a common cause of lateral knee pain related to intense physical activity resulting in chronic inflammation.
Commonly affect young patients who are physically active, most often long distance runners or cyclists. The exact prevalence is unknown, but one study has found the prevalence among actively training marines to be higher than 20% 5. Iliotibial band syndrome accounts for 12% of running-related overuse injuries 4.
Classically, ITBS is diagnosed by history and physical examination. Pain at the lateral knee joint is the presenting symptom with point tenderness 1-2 cm above the lateral joint line. Pain is usually worse with downhill running and increases throughout an episode of activity 4.
When the knee flexes, the iliotibial band (ITB) moves posteriorly along the lateral femoral epicondyle. When the band is excessively tight or stressed, the ITB rubs against the epicondyle irritating the lateral synovial recess. The histologic analysis demonstrates inflammation and hyperplasia in the synovium. The following physical factors are reported to be associated with the development of the syndrome 4:
- limb length discrepancy
- genu varum
- hip adductor weakness
- myofascial restriction
Allows visualisation of the impingement by assessing dynamic motion of the ITB through knee flexion and extension.
MRI is reserved for when the diagnosis is unclear and to exclude other etiologies of lateral knee pain such as a meniscal tear or lateral collateral ligament injury.
MR findings of ITBS include ill-defined signal abnormality within the fatty soft tissues interposed between the ITB and lateral femoral condyle, that is low signal on T1 and high on T2 weighted sequences, in keeping with oedema/fluid.
Cystic areas representing primary or secondary (adventitious) bursae may be identified.
Chronic MRI findings include thickening of the ITB and increased T2 signal intensity superficial to the ITB are occasionally seen
Lateral synovial recess may mimic as a joint fluid with soft tissue inflammatory changes.This is made easier by understanding that the anterior lateral synovial recess is located anterior to the lateral femoral epicondyle, in contrast to the inflammatory changes of ITBFS, which frequently overlie and extend posteriorly to the epicondyle
Treatment and prognosis
Initial treatment is conservative, consisting of physical therapy, anti-inflammatory medication, and steroid injections 3.
Surgical treatment is reserved only for those who fail conservative treatment and includes resection of the posterior aspect of the ITB 3.
General imaging differential considerations include:
- 1. Haims AH, Medvecky MJ, Pavlovich R et-al. MR imaging of the anatomy of and injuries to the lateral and posterolateral aspects of the knee. AJR Am J Roentgenol. 2003;180 (3): 647-53. AJR Am J Roentgenol (full text) - Pubmed citation
- 2. Muhle C, Ahn JM, Yeh L et-al. Iliotibial band friction syndrome: MR imaging findings in 16 patients and MR arthrographic study of six cadaveric knees. Radiology. 1999;212 (1): 103-10. Radiology (full text) - Pubmed citation
- 3. Khaund R, Flynn SH. Iliotibial band syndrome: a common source of knee pain. Am Fam Physician. 2005;71 (8): 1545-50. Am Fam Physician (link) - Pubmed citation
- 4. Hong JH, Kim JS. Diagnosis of iliotibial band friction syndrome and ultrasound guided steroid injection. Korean J Pain. 2013;26 (4): 387-91. doi:10.3344/kjp.2013.26.4.387 - Free text at pubmed - Pubmed citation
- 5. Linenger JM, West LA. Epidemiology of soft-tissue/musculoskeletal injury among U.S. Marine recruits undergoing basic training. Mil Med. 1992;157 (9): 491-3. - Pubmed citation
- 6. Jelsing EJ, Finnoff JT, Cheville AL et-al. Sonographic evaluation of the iliotibial band at the lateral femoral epicondyle: does the iliotibial band move?. J Ultrasound Med. 2013;32 (7): 1199-206. doi:10.7863/ultra.32.7.1199 - Pubmed citation