Presentation
A female paient presented with right lateral knee pain.
Patient Data
A focal septated fluid collection is noted between the iliotibial band and lateral femoral condyle, compatible with an adventitial bursa.
The bone marrow signal intensity of the imaged bones is within normal with the normal appearance of the covering cartilages.
Both menisci, both cruciate ligaments, both collateral ligaments appear intact with no evidence of tendinosis or tear. There is chondromalacia patellae. The patellar retinacula appear normal.
The patellar tendon, quadriceps, and Hoffa’s fat pad are normal.
There is minimal knee joint effusion.
The visualized muscles, vessels, and nerves are unremarkable.
Case Discussion
A female athlete (runner) patient presented with right lateral knee pain shows a focal septated fluid collection is noted between the iliotibial band (ITB) and lateral femoral condyle, compatible with an adventitial bursa.
This is one of the friction syndromes, where the ITB glides repeatedly over the lateral femoral condyle of the knee, the other over the greater trochanter of the hip.
Iliotibial band friction syndrome manifests on MR imaging as poorly defined high T2 signal intensity or a circumscribed fluid collection deep to the iliotibial band. The localized fluid collections are more likely caused by inflammation of the adventitious bursa.