Osteochondritis dissecans of the lateral femoral condyle.

Osteochondritis dissecans (OD) is a rare occurrence. In the knee, the most common localization is the lateral region of the internal femoral condyle. Involvement of the external condyle only occurs in 15% of cases, but its features are such that the situation is an entity in itself. The lesion is generally localized in the posterior site, and it is more extensive and more symptomatic as compared to medial localizations; moreover, early and rapid arthritic progression is observed. Reported here are 2 cases of OD of the lateral femoral condyle with atypical features in terms of clinical findings and progression of the disease as compared to more frequently occurring medial localizations.