Osteochondritis dissecans (OCD) of the knee joint usually occurs on the lateral aspect of the medial femoral condyle or the so called “classical site”. However, it rarely occurs on the lateral femoral condyle. We report 5 cases of 7 knees of OCD on the lateral femoral condyle associated with discoid lateral meniscus. The OCD lesion existed in the posterior portion of the lateral femoral condyle. Existence of the discoid meniscus subjected the lateral femoral condyle to repeated stresses by its thickness and morphology around 45 degrees of knee flexion. This abnormal load may pose as the main cause of OCD of the lateral femoral condyle.
