Fig. 4

A grade 2 lesion at the lateral femoral condyles near the intercondyloid fossa, missed by US. a On the US, the diagnosis was normal (grade 0), but on arthroscopy b, the diagnosis was grade 2 (black arrow) cartilage defect, presenting as a velvet-like formation with intact cartilage surface, located at the lateral femoral condyles near the intercondyloid fossa