Shigeru Ehara MD, Presenter: Nothing to Disclose

Fabella is the sasamoid in the lateral head of the gastrocnemius, seen in 10-30%. Fabella syndrome is painful posterolateral knee at the location of the fabella at full extension of the knee, and considered to be chondromalacia. The objective is to elucidate specific MR imaging and other imaging features of fabella syndrome.

Included in this presentation are the frequency of fabella syndrome (chondromalacia in the fabellar region), imaging features of plain radiography, bone scintigraphy, and MR imaging of the fabella syndrome. Localized articular cartilage lesion and osteophyte formation at the fabella are characteristic findings of this syndrome, particularly well demonstrated on MR imaging, and it will be emphacized in the presentation.

Localized degenerative change, or chondromalacia, in the fabellar region is a relatively common finding on MR imaging, and it may be defined as fabella syndrome. In addition to the osteophyte formation of the fabella, MR imaging is particularly useful to reveal localized pure cartilage lesions.

Ehara, S, Fabella Syndrome: MR Imaging Features of This Forgotten Entity.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9008175.html