Age / Sex : 42 / M

Age/Sex: 42/M

Chief complaint: Anterolateral knee pain over the lateral femoral epicondyle, developed three weeks ago after hiking

1) What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

* Send Application Answers to In Sook Lee, MD ([email protected])

Courtesy : Won-Hee Jee, MD, Seoul St. Mary’s Hospital

Iliotibial band friction syndrome

Discussion

Findings: Axial and coronal fat-suppressed intermediate-weighted MR images show ill-defined hyperintense signal localized deep to the iliotibial band where it passes over lateral femoral epicondyle.

Differential Diagnosis: Fluid in Lateral Knee Joint Recess, Lateral collateral ligament complex injury, Direct Blow Contusion, Excessive Lateral Pressure Syndrome.

Diagnosis:  Iliotibial band friction syndrome

Discussion: Iliotibial band friction syndrome (ITBFS) is an overuse syndrome which affects soft tissue interposed between iliotibial band and the lateral femoral condyle. Repetitive flexion and extension of the knee joints causes the ITB to rub on the lateral femoral epicondyle, which gives rise to an inflammatory reaction in the soft tissue deep to the ITB. The contact between ITB and lateral femoral condyle is known to be maximal at 20-30’ of flexion. Although it is often related to intense physical activity as occurs in long-distance runners, cyclists and American football players, non-athletes or amateur athletes can also been afflicted. The diagnosis is often made with clinical symptom and provocation test which reproduces pain during active knee movement while manual pressure is exerted over the lateral femoral epicondyle. However, it is not uncommon for this syndrome to be misdiagnosed clinically to lateral meniscal tear, lateral collateral ligament injury or popliteal tendinitis.

The most common MR finding is poorly defined increased signal in the fatty tissue deep to the ITB, which can propagate proximally and distally from the level of lateral epicondyle. When involved more severely, the abnormal signal further extends superficial to ITB. Thickening of the ITB may represent a chronic stage of ITBFS. The abnormal signal tends to predominate in the posterior aspect of the region beneath the ITB because posterior fibers of the ITB stay in contact with the lateral femoral epicondyle for a longer duration than anterior fibers while active knee movement. Well-demarcated fluid collection deep to the ITB are shown in some cases and regarded as an adventitious bursa formation or lateral synovial recess. Occasional reactive marrow edema in adjacent lateral femoral condyle was reported.

ITBFS responds well to cessation of the inciting activity, local physiotherapy and medication of NSAIDs. For the rare cases recalcitrant to the conservative therapy, local steroid injection or surgical treatment such as focal excision or lengthening of the ITB can be attempted.

References:

1. Renne JW. The iliotibial band friction syndrome. J Bone Joint Surg Am. 1975;57(8):1110-1111.

2. Murphy BJ, Hechtman KS, Uribe JW, Selesnick H, Smith RL, Zlatkin MB. Iliotibial band friction syndrome: MR imaging findings. Radiology. 1992;185(2):569-571.

3. Nishimura G, Yamato M, Tamai K, Takahashi J, Uetani M. MR findings in iliotibial band syndrome. Skeletal Radiol. 1997;26(9):533-537.

4. 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):103-110.

5. Vasilevska V, Szeimies U, Stabler A. Magnetic resonance imaging signs of iliotibial band friction in patients with isolated medial compartment osteoarthritis of the knee. Skeletal Radiol. 2009;38(9):871-875.

6. Sonin A, Manaster B, Andrews C, Crim J, Tuite M, Zoga A. Diagnostic Imaging Musculoskeletal : Trauma. 1st ed, 2010:104-107.